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Sample records for headspace chromatographic method

  1. A novel headspace gas chromatographic method for in situ monitoring of monomer conversion during polymerization in an emulsion environment.

    Science.gov (United States)

    Chai, Xin-Sheng; Zhong, Jin-Feng; Hu, Hui-Chao

    2012-05-18

    This paper describes a novel multiple-headspace extraction/gas chromatographic (MHE-GC) technique for monitoring monomer conversion during a polymerization reaction in a water-based emulsion environment. The polymerization reaction of methyl methacrylate (MMA) in an aqueous emulsion is used as an example. The reaction was performed in a closed headspace sample vial (as a mini-reactor), with pentane as a tracer. In situ monitoring of the vapor concentration of the tracer, employing a multiple headspace extraction (sampling) scheme, coupled to a GC, makes it possible to quantitatively follow the conversion of MMA during the early stages of polymerization. Data on the integrated amount of the tracer vapor released from the monomer droplet phase during the polymerization is described by a mathematic equation from which the monomer conversion can be calculated. The present method is simple, automated and economical, and provides an efficient tool in the investigation of the reaction kinetics and effects of the reaction conditions on the early stage of polymerization. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Discrimination of different hop varieties using headspace gas chromatographic data

    Directory of Open Access Journals (Sweden)

    Jorge Katia

    2003-01-01

    Full Text Available Methods for characterization of hop varieties include analyses of bitter acids and essential oils, followed by comparison of the chemical composition, particularly chromatographic profiles. In the present work discrimination of different hop varieties was carried out based on their essential oil volatile composition, assessed by headspace gas chromatography, with subsequent statistical treatment of the data. Differences and similarities were determined in samples from USA, New Zealand and Europe, using correlation and cluster analysis. Aroma hops presented low levels of myrcene while bitter samples showed high levels of beta-caryophyllene, aloaromadendrene and also the sum of the marker ratios, independently of being in the form of pellets or extracts. Highly correlated samples with no significant differences have good possibility to substitute each other in the beer manufacture.

  3. Optimization of a novel headspace-solid-phase microextraction-gas chromatographic method by means of a Doehlert uniform shell design for the analysis of trace level ethylene oxide residuals in sterilized medical devices.

    Science.gov (United States)

    DiCicco, Michael P; Lang, Bridget; Harper, Thomas I

    2009-06-01

    Medical devices sterilized by ethylene oxide (EtO) retain trace quantities of EtO residuals, which may irritate patients' tissue. Reliably quantifying trace level EtO residuals in small medical devices requires an extremely sensitive analytical method. In this research, a Doehlert uniform shell design was utilized in obtaining a response surface to optimize a novel headspace-solid-phase microextraction-gas chromatographic (HS-SPME-GC) method developed for analyzing trace levels of EtO residuals in sterilized medical devices, by evaluating sterilized, polymer-coated, drug-eluting cardiovascular stents. The effects of four independent experimental variables (HS-SPME desorption time, extraction temperature, GC inlet temperature and extraction time) on GC peak area response of EtO were investigated simultaneously and the most influential experimental variables determined were extraction temperature and GC inlet temperature, with the fitted model showing no evidence of lack-of-fit. The optimized HS-SPME-GC method demonstrated overall good linearity/linear range, accuracy, repeatability, reproducibility, absolute recovery and high sensitivity. This novel method was successfully applied to analysis of trace levels of EtO residuals in sterilized/aerated cardiovascular stents of various lengths and internal diameter, where, upon heating, trace EtO residuals fully volatilized into HS for extraction, thereby nullifying matrix effects. As an alternative, this novel HS-SPME-GC method can offer higher sensitivity compared with conventional headspace analyzer-based sampling.

  4. Development of an equilibrium headspace gas chromatographic method for the measurement of noncovalent association and partitioning of n-alkylbenzenes at infinite dilution in fulvic acid pseudophase.

    Science.gov (United States)

    Eljack, Mahmoud D; Wilson, Rachael E; Hussam, Abul; Khan, Shahamat U

    2015-02-27

    Fulvic acid (FA), the most important water soluble fraction of humic substances in nature, is known to form aggregate pseudophase and complexes with organic and inorganic species. Here, we report a novel equilibrium headspace gas chromatography (eHSGC) and a two-step reaction model to measure n-alkylbenzene-FA association constant (K11) and n-alkylbenzene-pseudophase FAn association constant (Kn1) without solute concentration and response factor. The K11 and Kn1 values were 2-3 orders of magnitude higher than those for sodium dodecylsulfate. Changes in peak area were used to calculate the critical FA-aggregation concentration (cfc), mole fraction based partition coefficients (Kx), activity coefficients of solute inside the aggregate pseudophase (γm(∞)), and transfer free energies of alkyl CH2 at infinite dilution. The cfc was found to be 10±0.5μM. The Kx values are of the order of 10(7) in the FA-aggregate pseudophase. The data shows that benzene has the lowest (0.0002) and n-butylbenzene has the highest (0.01) γm(∞) values, which are seven orders of magnitude smaller than γw(∞) in water. The transfer free energy of association of a CH2 group, -155cal/mol, compared to that of benzene, -9722cal/mol, indicates that the FA-aggregate pseudophase is more polarizable benzene-like and less n-alkane aliphatic-like. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Headspace

    OpenAIRE

    Dall, Christoffer; Bruun, Lotus Joanne Noamynte; Laybourn, Stine; Tromholt-Richter, Julius

    2016-01-01

    This project is centered around an organization called headspace. Headspace provides young people in the age group 12-25 with someone to talk to about their problems. Their policy is, that all problems can be addressed - minor as well as bigger. During a visit at headspace in Roskilde their volunteers informed us that many of their visitors confuse headspace’s offers with psychological help solely, and many in general are confused about what headspace has to offer their visitors. This project...

  6. A simple headspace equilibration method for measuring dissolved methane

    Science.gov (United States)

    Magen, C; Lapham, L.L.; Pohlman, John W.; Marshall, Kristin N.; Bosman, S.; Casso, Michael; Chanton, J.P.

    2014-01-01

    Dissolved methane concentrations in the ocean are close to equilibrium with the atmosphere. Because methane is only sparingly soluble in seawater, measuring it without contamination is challenging for samples collected and processed in the presence of air. Several methods for analyzing dissolved methane are described in the literature, yet none has conducted a thorough assessment of the method yield, contamination issues during collection, transport and storage, and the effect of temperature changes and preservative. Previous extraction methods transfer methane from water to gas by either a "sparge and trap" or a "headspace equilibration" technique. The gas is then analyzed for methane by gas chromatography. Here, we revisit the headspace equilibration technique and describe a simple, inexpensive, and reliable method to measure methane in fresh and seawater, regardless of concentration. Within the range of concentrations typically found in surface seawaters (2-1000 nmol L-1), the yield of the method nears 100% of what is expected from solubility calculation following the addition of known amount of methane. In addition to being sensitive (detection limit of 0.1 ppmv, or 0.74 nmol L-1), this method requires less than 10 min per sample, and does not use highly toxic chemicals. It can be conducted with minimum materials and does not require the use of a gas chromatograph at the collection site. It can therefore be used in various remote working environments and conditions.

  7. Fast Chromatographic Method for Explosive Profiling

    Directory of Open Access Journals (Sweden)

    Pierre-Hugues Stefanuto

    2015-05-01

    Full Text Available Security control is becoming a major global issue in strategic locations, such as airports, official buildings, and transit stations. The agencies responsible for public security need powerful and sensitive tools to detect warfare agents and explosives. Volatile signature detection is one of the fastest and easiest ways to achieve this task. However, explosive chemicals have low volatility making their detection challenging. In this research, we developed and evaluated fast chromatographic methods to improve the characterization of volatile signatures from explosives samples. The headspace of explosives was sampled with solid phase micro-extraction fiber (SPME. Following this step, classical gas chromatography (GC and comprehensive two-dimensional GC (GC×GC were used for analysis. A fast GC approach allows the elution temperature of each analyte to be decreased, resulting in decreased thermal degradation of sensitive compounds (e.g., nitro explosives. Using fast GC×GC, the limit of detection is further decreased based on the cryo-focusing effect of the modulator. Sampling of explosives and chromatographic separation were optimized, and the methods then applied to commercial explosives samples. Implementation of fast GC methods will be valuable in the future for defense and security forensics applications.

  8. Method for improving accuracy in full evaporation headspace analysis.

    Science.gov (United States)

    Xie, Wei-Qi; Chai, Xin-Sheng

    2017-05-01

    We report a new headspace analytical method in which multiple headspace extraction is incorporated with the full evaporation technique. The pressure uncertainty caused by the solid content change in the samples has a great impact to the measurement accuracy in the conventional full evaporation headspace analysis. The results (using ethanol solution as the model sample) showed that the present technique is effective to minimize such a problem. The proposed full evaporation multiple headspace extraction analysis technique is also automated and practical, and which could greatly broaden the applications of the full-evaporation-based headspace analysis. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Gas chromatographic analysis of volatile sulfur compounds from heated milk using static headspace sampling.

    Science.gov (United States)

    Christensen, K R; Reineccius, G A

    1992-08-01

    An investigation was conducted to test the feasibility of using gas chromatography with static headspace sampling as an objective tool to measure milk flavor quality. Heated milk off-flavor was chosen for study. Different strategies were tried for increasing the sensitivity of a commercially available headspace method, including salting out with sodium sulfate, cryofocusing during injection, and applying backpressure to the sampling loop. With the aid of a sulfur-specific detector, the resulting system was sufficiently sensitive to detect the sulfur volatiles, H2S and dimethyl sulfide, at the concentrations found in pasteurized skim milk. Milk that was heated to varying degrees was analyzed, and the analytical results were compared with the intensity of heated flavor as determined by a sensory panel. For skim milk, correlations were moderately strong: Spearman's correlation coefficients for H2S and dimethyl sulfide were .75 and .60, respectively. Correlations were weak for whole milk.

  10. Rapid headspace solid-phase microextraction-gas chromatographic-time-of-flight mass spectrometric method for qualitative profiling of ice wine volatile fraction. II: Classification of Canadian and Czech ice wines using statistical evaluation of the data.

    Science.gov (United States)

    Setkova, Lucie; Risticevic, Sanja; Pawliszyn, Janusz

    2007-04-20

    The previously developed and optimized headspace solid-phase microextraction (HS-SPME)-GC-time-of-flight (TOF) MS analytical method for the determination of compounds with a wide range of polarities and volatilities was successfully used in this study to characterize and classify a large set of ice wines according to their origin, grape variety and oak or stainless steel fermentation/ageing conditions, based on a statistical evaluation (principal component analysis (PCA)) of the measured data. More than 130 ice wine samples collected directly from Canadian and Czech wine producers were analyzed in this study. The SPME step was beneficially carried out utilizing the new-generation super elastic divinylbenzene/Carboxen/polydimethylsiloxane (DVB/CAR/PDMS) 50 microm/30 microm fiber assembly. One fiber was used for the whole sequence of ice wine samples, control and blank experiments, which consisted of more than 600 individual extraction/injection cycles. Utilizing the high-speed TOF analyzer, full spectral information within the range of 35-450 u was collected for the entire GC run (as short as 4.5 min) without compromising in the detection sensitivity, as compared to other scanning mass analyzers operated in selected ion monitoring or MS(n) mode to achieve similar sensitivity. The identification of analytes was performed by a combination of the linear temperature-programmed retention index (LTPRI) approach with the comparison of the obtained spectra with three libraries included in the ChromaTOF software. A total of 201 peaks were tentatively assigned as ice wine aroma components and 58 of those compounds were evaluated in all of the examined samples.

  11. Analysis of hydrogen and methane in seawater by "Headspace" method: Determination at trace level with an automatic headspace sampler.

    Science.gov (United States)

    Donval, J P; Guyader, V

    2017-01-01

    "Headspace" technique is one of the methods for the onboard measurement of hydrogen (H2) and methane (CH4) in deep seawater. Based on the principle of an automatic headspace commercial sampler, a specific device has been developed to automatically inject gas samples from 300ml syringes (gas phase in equilibrium with seawater). As valves, micro pump, oven and detector are independent, a gas chromatograph is not necessary allowing a reduction of the weight and dimensions of the analytical system. The different steps from seawater sampling to gas injection are described. Accuracy of the method is checked by a comparison with the "purge and trap" technique. The detection limit is estimated to 0.3nM for hydrogen and 0.1nM for methane which is close to the background value in deep seawater. It is also shown that this system can be used to analyze other gases such as Nitrogen (N2), carbon monoxide (CO), carbon dioxide (CO2) and light hydrocarbons. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Application of microwave-assisted desorption/headspace solid-phase microextraction as pretreatment step in the gas chromatographic determination of 1-naphthylamine in silica gel adsorbent.

    Science.gov (United States)

    Yan, Cheing-Tong; Jen, Jen-Fon; Shih, Tung-Sheng

    2007-03-30

    Pretreatment of silica gel sample containing 1-naphthylamine by microwave-assisted desorption (MAD) coupled to in situ headspace solid phase microextraction (HS-SPME) has been investigated as a possible alternative to conventional methods prior to gas chromatographic (GC) analysis. The 1-naphthylamine desorbs from silica gel to headspace under microwave irradiation, and directly absorbs onto a SPME fiber located in a controlled-temperature headspace area. After being collected on the SPME fiber, and desorbed in the GC injection port, 1-naphthylamine is analyzed by GC-FID. Parameters that influence the extraction efficiency of the MAD/HS-SPME, such as the extraction media and its pH, the microwave irradiation power and irradiation time as well as desorption conditions of the GC injector, have been investigated. Experimental results indicate that the extraction of a 150mg silica gel sample by using 0.8ml of 1.0M NaOH solution and a PDMS/DVB fiber under high-powered irradiation (477W) for 5min maximizes the extraction efficiency. Desorption of 1-naphthylamine from the SPME fiber in GC injector is optimal at 250 degrees C held for 3min. The detection limit of method is 8.30ng. The detected quantity of 1-naphthylamine obtained by the proposed method is 33.3 times of that obtained by the conventional solvent extraction method for the silica gel sample containing 100ng of 1-naphthylamine. It provides a simple, fast, sensitive and organic-solvent-free pretreatment procedure prior to the analysis of 1-naphthylamine collected on a silica gel adsorbent.

  13. Headspace Solid Phase Micro Extraction Gas Chromatographic Determination of Fenthion in Human Serum

    OpenAIRE

    Kasiotis, Konstantinos M.; Souki, Helen; Tsakirakis, Angelos N.; Carageorgiou, Haris; Theotokatos, Spiridon A.; Haroutounian, Serkos A.; Machera, Kyriaki

    2008-01-01

    A simple and effective analytical procedure was developed for the determination of fenthion residues in human serum samples. The sample treatment was performed using the headspace solid-phase micro extraction with polyacrylate fiber, which has the advantage to require low amount of serum (1 mL) without tedious pre-treatment. The quantification of fenthion was carried out by gas chromatography-mass spectrometry and the recoveries ranged from 79 to 104% at two spiking levels for 6 replicates. D...

  14. Development of headspace solid-phase microextraction method for ...

    African Journals Online (AJOL)

    A headspace solid-phase microextraction (HS-SPME) method was developed as a preliminary investigation using univariate approach for the analysis of 14 multiclass pesticide residues in fruits and vegetable samples. The gas chromatography mass spectrometry parameters (desorption temperature and time, column flow ...

  15. Headspace Solid Phase Micro Extraction Gas Chromatographic Determination of Fenthion in Human Serum

    Directory of Open Access Journals (Sweden)

    Kyriaki Machera

    2008-05-01

    Full Text Available A simple and effective analytical procedure was developed for the determination of fenthion residues in human serum samples. The sample treatment was performed using the headspace solid-phase micro extraction with polyacrylate fiber, which has the advantage to require low amount of serum (1 mL without tedious pre-treatment. The quantification of fenthion was carried out by gas chromatography-mass spectrometry and the recoveries ranged from 79 to 104% at two spiking levels for 6 replicates. Detection and quantification limits were calculated as 1.51 and 4.54 ng/mL of serum respectively. Two fenthion metabolites − fenoxon and fenthion–sulfoxide − were also identified.

  16. Liquid chromatographic-mass spectrometric method for ...

    African Journals Online (AJOL)

    spectrometer (Agilent Technologies, USA) with an electrospray ionization interface (ESI) and coupled to an Agilent 1200 HPLC (Agilent. Technologies,. USA). Chromatographic ... Technologies, Palo Alto, CA, USA) kept at a constant temp of 25 ± 2 °C. .... precision of the method was represented as the relative standard ...

  17. Time since discharge of 9mm cartridges by headspace analysis, part 1: Comprehensive optimisation and validation of a headspace sorptive extraction (HSSE) method.

    Science.gov (United States)

    Gallidabino, M; Romolo, F S; Weyermann, C

    2017-03-01

    Estimating the time since discharge of spent cartridges can be a valuable tool in the forensic investigation of firearm-related crimes. To reach this aim, it was previously proposed that the decrease of volatile organic compounds released during discharge is monitored over time using non-destructive headspace extraction techniques. While promising results were obtained for large-calibre cartridges (e.g., shotgun shells), handgun calibres yielded unsatisfying results. In addition to the natural complexity of the specimen itself, these can also be attributed to some selective choices in the methods development. Thus, the present series of paper aimed to more systematically evaluate the potential of headspace analysis to estimate the time since discharge of cartridges through the use of more comprehensive analytical and interpretative techniques. Specifically, in this first part, a method based on headspace sorptive extraction (HSSE) was comprehensively optimised and validated, as the latter recently proved to be a more efficient alternative than previous approaches. For this purpose, 29 volatile organic compounds were preliminary selected on the basis of previous works. A multivariate statistical approach based on design of experiments (DOE) was used to optimise variables potentially involved in interaction effects. Introduction of deuterated analogues in sampling vials was also investigated as strategy to account for analytical variations. Analysis was carried out by selected ion mode, gas chromatography coupled to mass spectrometry (GC-MS). Results showed good chromatographic resolution as well as detection limits and peak area repeatability. Application to 9mm spent cartridges confirmed that the use of co-extracted internal standards allowed for improved reproducibility of the measured signals. The validated method will be applied in the second part of this work to estimate the time since discharge of 9mm spent cartridges using multivariate models. Copyright

  18. Gas chromatographic head-space determination of residual acrylonitrile in acrylonitrile-butadiene-styrene resins and migration into a simulated fatty foodstuffs liquid.

    Science.gov (United States)

    Di Pasquale, G; Di Iorio, G; Capaccioli, T

    1978-10-11

    Head-space methods are described for the determination of residual acrylonitrile in acrylonitrile-butadiene-styrene resins and in olive oil, which simulates fatty foodstuffs. Dimethylformamide was used as solvent for the resin, with flame ionization detection. The injection of water into the resin dispersion prior to head-space analysis greatly enhances the detection capabilities. The use of a nitrogen-selective detector required dimethyl sulphoxide as the solvent. The determination of acrylonitrile in olive oil was carried out employing both types of detector. The detection sensitivity was much greater with the nitrogen-selective detector.

  19. [Analytical method and comparison for static and dynamic headspace gas chromatography of anisole in water].

    Science.gov (United States)

    Zhang, Yan; Qian, Jie-feng; Liu, Lan-xia; Zhao, Hui-qin

    2013-01-01

    To establish and compare the method of static headspace gas chromatography hydrogen flame detector (static headspace method) and purge and trap gas chromatography-mass spectrometry (dynamic headspace method) of anisole in water. Nitrogen gas was used as carrier gas in the static headspace method, 5 g NaCl as matrix modifier was added into 10 ml water. The sample was balanced with high speed vibration at 75°C for 30 min, and anisole was detected by gas chromatography and quantified with external standard. Helium was used as carrier gas in dynamic headspace method, 5.0 ml water and 0.004 mg/L internal standard fluorobenzene was purged into the purge and trap apparatus. After purging, trapping and desorption, anisole was detected by the gas chromatography-mass spectrograph, confirmed by the retention time and comparison of mass-spectrogram in spectrum library and quantified with internal standard. The repeatability and sensitivity of assay were evaluated. A good linear range for anisole was observed in static headspace gas chromatography and dynamic headspace gas chromatography-mass spectrometry, within the range of 10 - 500 µg/L and 0.5 - 60.0 µg/L respectively. The linear regression equation was Y = 782.150X + 1.3446 and Y = 0.0358X - 0.0209 respectively, both the correlation coefficient ≥ 0.999. The detection limit (LOD) were 0.002 µg/L and 0.110 µg/L, the lower limit of quantitation (LOQ) were 0.006 µg/L and 0.350 µg/L, the relative standard deviation (RSD) were 1.8% - 2.3% and 2.0% - 3.4%, and the spiking recovery were 93% - 101% and 96% - 101% respectively. The methods of static headspace gas chromatography and dynamic headspace gas chromatography-mass spectrometry are simple and can measure anisole in water quickly, sensitively and accurately.

  20. Influence of fibre coating in headspace solid-phase microextraction-gas chromatographic analysis of aromatic and medicinal plants.

    Science.gov (United States)

    Bicchi, C; Drigo, S; Rubiolo, P

    2000-09-15

    Solid-phase microextraction (SPME) is a solvent-free technique, which is well established in headspace analysis since it is sensitive, because of the concentration factor achieved by the fibres, and selective, because of different coating materials which can be used. The performance of eight commercially available SPME fibres was compared to evaluate the recoveries of some characteristic components with different polarities and structures present in the headspace of four aromatic and medicinal plants: rosemary (Rosmarinus officinalis L.), sage (Salvia officinalis L.), thyme (Thymus vulgaris L.) and valerian (Valeriana officinalis L.). The relative concentration capacity of each fibre on the same components of each plant was also determined by comparing their abundance with that obtained by classical static-headspace GC. The partition coefficient, K1, between the headspace gaseous phase and SPME polymeric coating, and the relative concentration factors, of some of the characteristic components of the plant investigated dissolved in dibutyl phtalate, were also determined, under rigorously standardised analysis conditions. The results showed that the most effective fibres were those consisting of two components, i.e., a liquid phase (polydimethylsiloxane) and a porous solid (carboxen or divinylbenzene, or both).

  1. [Analysis of residual solvents in natural flavorings by headspace GC using the standard addition method].

    Science.gov (United States)

    Sato, Kyoko; Uematsu, Yoko; Isagawa, Satoshi; Tateba, Hideki; Tomizawa, Masahito; Oosaki, Kazuhiko; Hasebe, Akio; Shibuya, Saburo; Nii, Hiromichi; Higashinaka, Ryuji; Watanabe, Ichiro; Yamazaki, Takeshi; Tanamoto, Ken-ichi; Maitani, Tamio

    2004-12-01

    Headspace GC using the standard addition method has been developed for the simultaneous determination of organic solvents in natural flavorings. The procedure can be outlined as follows: an aliquot of the sample is transferred to a 10 mL vial. To each vial, a DMSO solution containing solvents at different concentrations is added as the standard solution. The vials are kept at 50 degrees C (for automatic injection) or 40 degrees C (for hand-operated injection) for 40 minutes. One mL of the vapor phase in each vial is injected into a gas chromatograph equipped with an Aquatic-2 column (0.25 mm i.d. x 60 m). To evaluate this method, we conducted a performance study in collaboration with 10 laboratories, using ginger oleoresin. We analyzed 6 solvents (methanol, 2-propanol, acetone, dichloromethane, hexane, and 1,1,2-trichloroethene) for which the maximum residue limits are established in Japan's Specifications and Standards for Food Additives. Methanol and acetone existed in the ginger oleoresin, so only the other that four kinds of solvents were added to it. Eight of the laboratories used automatic injection, while the remaining two used hand-operated injection. Statistical analyses were conducted on the data obtained from the 8 laboratories. Repeatability standard deviations (RSDr) ranged from 4.3 to 11.4%, and reproducibility standard deviations (RSDR) ranged from 8.4 to 19.0%.

  2. Multiple responses optimization in the development of a headspace gas chromatography method for the determination of residual solvents in pharmaceuticals

    Directory of Open Access Journals (Sweden)

    Carla M. Teglia

    2015-10-01

    Full Text Available An efficient generic static headspace gas chromatography (HSGC method was developed, optimized and validated for the routine determination of several residual solvents (RS in drug substance, using a strategy with two sets of calibration. Dimethylsulfoxide (DMSO was selected as the sample diluent and internal standards were used to minimize signal variations due to the preparative step. A gas chromatograph from Agilent Model 6890 equipped with flame ionization detector (FID and a DB-624 (30 m×0.53 mm i.d., 3.00 µm film thickness column was used. The inlet split ratio was 5:1. The influencing factors in the chromatographic separation of the analytes were determined through a fractional factorial experimental design. Significant variables: the initial temperature (IT, the final temperature (FT of the oven and the carrier gas flow rate (F were optimized using a central composite design. Response transformation and desirability function were applied to find out the optimal combination of the chromatographic variables to achieve an adequate resolution of the analytes and short analysis time. These conditions were 30 °C for IT, 158 °C for FT and 1.90 mL/min for F. The method was proven to be accurate, linear in a wide range and very sensitive for the analyzed solvents through a comprehensive validation according to the ICH guidelines.

  3. An Economical Method for Static Headspace Enrichment for Arson Analysis

    Science.gov (United States)

    Olesen, Bjorn

    2010-01-01

    Static headspace analysis of accelerants from suspected arsons is accomplished by placing an arson sample in a sealed container with a carbon strip suspended above the sample. The sample is heated, cooled to room temperature, and then the organic components are extracted from the carbon strip with carbon disulfide followed by gas chromatography…

  4. Rapid validated liquid chromatographic method coupled with ...

    African Journals Online (AJOL)

    of 2 - 150 ng/mL and determination coefficient of ≥ 0.999. Intra- and inter-day accuracy and precision ... LC/MS (Agilent Technologies, Palo Alto, CA,. USA). Chromatographic separation was .... Table 2: Intra-day and inter-day precision and accuracy of NTB (QC) samples. Day of analysis. NTB measured concentration in ...

  5. Study of the Behaviors of Gunshot Residues from Spent Cartridges by Headspace Solid-Phase Microextraction-Gas Chromatographic Techniques.

    Science.gov (United States)

    Chang, Kah Haw; Yew, Chong Hooi; Abdullah, Ahmad Fahmi Lim

    2015-07-01

    Gunshot residues, produced after shooting activity, have acquired their importance in analysis due to the notoriety of firearms-related crimes. In this study, solid-phase microextraction was performed to extract the headspace composition of spent cartridges using 85-μm polyacrylate fiber at 66°C for 21 min. Organic compounds, that is, naphthalene, 2,6-dinitrotoluene, 2,4-dinitrotoluene, diphenylamine, and dibutyl phthalate were detected and analyzed by gas chromatography-flame ionization detection technique. Evaluation of chromatograms for diphenylamine, dibutyl phthalate, and naphthalene indicates the period after a gunshot was discharged, whether it was 1 days, 2-4 days, <5 days, 10 days, 20 days, or more than 30 days ago. This study revealed the potential effects of environmental factors such as occasional wind blow and direct sunlight on the estimation of time after spent cartridges were discharged. In conclusion, we proposed reliable alternative in analyzing the headspace composition of spent cartridges in a simulated crime scene. © 2015 American Academy of Forensic Sciences.

  6. Chromatographic and electrophoretic methods for nanodisc purification and analysis

    DEFF Research Database (Denmark)

    Justesen, Bo Højen; Günther-Pomorski, Thomas

    2014-01-01

    of proper reconstitution are still major challenges during the sample preparation. This review gives an overview of the methods used for purifying and analyzing nanodiscs and nanodisc-reconstituted membrane proteins, with an emphasis on the chromatographic and electrophoretic approaches....

  7. Comparison of three liquid chromatographic methods with FDA optimized Monier-Williams method for determination of total sulfite in foods.

    Science.gov (United States)

    Lawrence, J F; Chadha, R K; Ménard, C

    1990-01-01

    Three liquid chromatographic (LC) methods employing amperometric detection were compared with the collaboratively studied FDA optimized Monier-Williams distillation method for the determination of total sulfite in 5 food types. The foods included lemon juice, white wine, instant mashed potatoes, golden raisins, and onion flakes. Two of the LC methods (one employing headspace sampling and the other direct injection) used ion-exchange chromatography with a basic mobile phase (pH about 10.8) and a glassy carbon electrode; the third (employing direct injection) used ion-exclusion chromatography with an acidic mobile phase (pH about 2) and a platinum electrode. All 4 methods produced similar results for the wine, lemon juice, and raisins. Results were different for instant mashed potatoes and onion flakes. The headspace-LC method and direct ion-exclusion LC method, both of which employed an alkaline sample extraction, yielded significantly higher values for sulfite in instant potatoes than did the other 2 methods. A large interfering peak with both direct LC methods prevented quantitation of sulfite in the onion flakes. All methods can detect sulfite as low as about 1 microgram/g in 4 of 5 food types examined.

  8. Determination of Odor Release in Hydrocolloid Model Systems Containing Original or Carboxylated Cellulose at Different pH Values Using Static Headspace Gas Chromatographic (SHS-GC) Analysis

    Science.gov (United States)

    Lee, Sang Mi; Shin, Gil-Ok; Park, Kyung Min; Chang, Pahn-Shick; Kim, Young-Suk

    2013-01-01

    Static headspace gas chromatographic (SHS-GC) analysis was performed to determine the release of 13 odorants in hydrocolloid model systems containing original or regio-selectively carboxylated cellulose at different pH values. The release of most odor compounds was decreased in the hydrocolloid solutions compared to control, with the amounts of 2-propanol, 3-methyl-1-butanol, and 2,3-butanedione released into the headspace being less than those of any other odor compound in the hydrocolloid model systems. However, there was no considerable difference between original cellulose-containing and carboxylated-cellulose containing systems in the release of most compounds, except for relatively long-chain esters such as ethyl caprylate and ethyl nonanoate. The release from the original and carboxylated cellulose solutions controlled to pH 10 was significantly higher than that from solutions adjusted to pH 4 and 7 in the case of some esters (ethyl acetate, methyl propionate, ethyl propionate, ethyl butyrate, butyl propionate, ethyl caproate) and alcohols (2-propanol, 3-methyl-1-butanol), in particular, ethyl butyrate and 3-methyl-1-butanol. In contrast, the release of 2,3-butanedione from both the original and carboxylated cellulose solutions was increased at pH 4 and 7 compared to that at pH 10 by about 70% and 130%, respectively. Our study demonstrated that the release of some odorants could be changed significantly by addition of both original and carboxylated cellulose in hydrocolloid model systems, but only minor effect was observed in pH of the solution. PMID:23447013

  9. A method for measuring free CO 2 in upland streamwater using headspace analysis

    Science.gov (United States)

    Hope, Diane; Dawson, Julian J. C.; Cresser, Malcolm S.; Billett, Michael F.

    1995-03-01

    Existing titration-based methods for the measurement of dissolved free CO 2 are indirect and require the measurement of a number of other determinands (e.g. pH); they may underestimate free CO 2 concentrations, because analysis is carried out frequently in an open vessel from which some free CO 2 may be lost prior to measurement. Here, a method of headspace analysis is described; this minimises CO 2 loss and provides a more direct technique for determining free CO 2 in low ionic strength, organic-rich upland streamwaters. A sample of streamwater is collected in a sealed flask and a headspace is created by pumping out a known volume of sample, replacing it with CO 2-scrubbed air. After equilibration of CO 2 between the remaining water and the headspace, the concentration of CO 2 in the headspace is measured using an Infra Red Gas Analyser. The concentration of free CO 2 in the original sample is then calculated using Henry's law. This method measured free CO 2 in standard solutions containing 1-10 mg l -1 free CO 2 to within 0.1 mg l -1. The method was used to measure free CO 2 in streamwater from 19 sites on the River Dee in north-east Scotland and the results were compared with those reported for streams elsewhere. Free CO 2 concentrations measured by headspace analysis were significantly higher than those found using acidimetric titration.

  10. Rapid method for determination of carbonyl groups in lignin compounds by headspace gas chromatography.

    Science.gov (United States)

    Li, Jing; Hu, Hui-Chao; Chai, Xin-Sheng

    2015-07-24

    The paper reports on a novel method for rapid determination of carbonyl in lignins by headspace gas chromatography (HS-GC). The method involves the quantitative carbonyl reduction for aldehydes in 2min at room temperature or for acetones in 30min at 80°C by sodium borohydride solution in a closed headspace sample vial. After the reaction, the solution was acidified by injecting sulfuric acid solution and the hydrogen released to the headspace was determined by GC using thermal-conductivity detector. The results showed that with the addition of SiO2 powder, the reduction reaction of carbonyl groups can be greatly facilitated. The method has a good measurement precision (RSD<7.74%) and accuracy (relative error <10% compared with a reference method) in the carbonyl quantification. It is suitable to be used for rapid determination of carbonyl content in lignin and related materials. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Development of a sensory test method for odor measurement in a package headspace

    DEFF Research Database (Denmark)

    Reinbach, Helene Christine; Allesen-Holm, Bodil Helene; Kristoffersson, Lars

    2011-01-01

    The aim of the present study was to develop a sensory method to evaluate off-odors in a package headspace relative to a reference scale. Selection of panelists was performed with a questionnaire and with the Sniffin' stick test. A 1-butanol reference scale and three types of scales (a 15-cm line...... to a physical intensity scale of 1-butanol and thus provides a valuable reference for comparing different package assessments over time. PRACTICAL APPLICATIONS A method for assessing off-odors in a package headspace is developed. The method development includes everything from selection and monitoring...... scale tended to give a greater accuracy of scored odor intensity. The color-graded brightness scale may strengthen the repeatability of the intensity measures due to the cross-modal support in the judgment processes. The method allows the conversion of intensity judgment of a package headspace...

  12. A Gas Chromatographic Method for the Determination of Bicarbonate and Dissolved Gases

    Directory of Open Access Journals (Sweden)

    John H. Loughrin

    2017-11-01

    Full Text Available A gas chromatographic method for the rapid determination of aqueous carbon dioxide and its speciation into solvated carbon dioxide and bicarbonate is presented. One-half mL samples are injected through a rubber septum into 20-mL vials that are filled with 9.5 mL of 0.1 N HCl. A one mL portion of the headspace is withdrawn and injected onto a gas chromatograph equipped with a thermal conductivity detector. Using the dimensionless Henry's constant for carbon dioxide and an adaptation of the Henderson-Hasselbalch equation, carbon dioxide in the samples can be categorized among solvated, bicarbonate, and carbonate forms. Natural water samples as well as wastewater from a municipal sewage treatment plant and a swine rearing operation were analyzed by this method and the results compared favorably to those obtained by titration. Samples stored for up to 5 weeks showed no significant changes in carbon dioxide concentrations. In addition, using flame ionization and electron capture detectors, methane and nitrous oxide concentrations in the samples were also measured.

  13. Physicochemical and chromatographic method of characterization of Matricaria recutita tinctures

    Directory of Open Access Journals (Sweden)

    Jonathan Parra

    2016-02-01

    Full Text Available Context: The pharmacological activity of medicinal products containing plant materials depends on their specific components. However, these components are not characterized in their entirety in all cases. Therefore, manufacturing processes must be duly characterized and validated. Aims: To characterize a chamomile (Matricaria recutita tincture through chemometric analysis of chromatographic data in order to establish quality parameters for its production. Methods: Various chamomile tinctures were manufactured and the precision and robustness of the production process for each was verified. The physicochemical properties of the tinctures were characterized and their chromatographic digital fingerprints analysed through chemometric methods. Results: A good correlation between the physicochemical characterization and the chromatographic analysis was demonstrated. The preparation methodology was proved to be repeatable as long as the source of the plant material is not altered. Conclusions: The principal component multivariate analysis of chromatograms was a helpful and simple tool for the characterization and traceability of the production method.

  14. Simple and accurate method for determining dissolved inorganic carbon in environmental water by reaction headspace gas chromatography.

    Science.gov (United States)

    Xie, Wei-Qi; Gong, Yi-Xian; Yu, Kong-Xian

    2017-11-29

    We investigate a simple and accurate method for quantitatively analyzing dissolved inorganic carbon in environmental water by reaction headspace gas chromatography. The neutralization reaction between the inorganic carbon species (i.e., bicarbonate ions and carbonate ions) in environmental water and hydrochloric acid is carried out in a sealed headspace vial, and the carbon dioxide formed from the neutralization reaction, the self-decomposition of carbonic acid and dissolved carbon dioxide in environmental water is then analyzed by headspace gas chromatography. The data show that the headspace gas chromatography method has good precision (relative standard deviation ≤ 1.63%) and accuracy (relative differences ≤ 5.81% compared with the coulometric titration technique). The headspace gas chromatography method is simple, reliable and can be well applied in the dissolved inorganic carbon detection in environmental water. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  15. Furan in food: headspace method and product survey.

    Science.gov (United States)

    Zoller, O; Sager, F; Reinhard, H

    2007-01-01

    Headspace gas chromatography-mass spectrometry (GC-MS) has been adapted for the efficient determination of furan in foods. Levels of furan in various foods were measured in order to identify the products that contribute most to the human intake of furan. Highest amounts were found in products that were heat treated in sealed containers such as jarred and canned food products and in crusty and dry products such as snacks, biscuits, bread crust, roasted wheat flour and roasted coffee beans. Of the analysed jarred baby food products those containing only meat and starch from rice and corn had low levels of furan. In addition, the fruit products showed similar low levels. Clearly higher concentrations were found in the vegetable and vegetable-meat products. For the adult population coffee seems to be an important product with respect to furan intake. Coffee brews from espresso-type machines had considerably higher amounts of furan than other coffee brews. This type of coffee is considered by experts to have the best coffee aroma. It is assumed that for regular coffee consumers coffee is the most important source of furan intake.

  16. Evaluation of headspace equilibration methods for quantifying greenhouse gases in groundwater.

    Science.gov (United States)

    Jahangir, M M R; Johnston, P; Khalil, M I; Grant, J; Somers, C; Richards, K G

    2012-11-30

    The objective of the study was to evaluate the different headspace equilibration methods for the quantification of dissolved greenhouse gases in groundwater. Groundwater samples were collected from wells with contrasting hydrogeochemical properties and degassed using the headspace equilibration method. One hundred samples from each well were randomly selected, treatments were applied and headspace gases analysed by gas chromatography. Headspace equilibration treatments varied helium (He):water ratio, shaking time and standing time. Mean groundwater N(2)O, CO(2) and CH(4) concentrations were 0.024 mg N L(-1), 13.71 mg C L(-1) and 1.63 μg C L(-1), respectively. All treatments were found to significantly influence dissolved gas concentrations. Considerable differences in the optimal He:water ratio and standing time were observed between the three gases. For N(2)O, CO(2) and CH(4) the optimum operating points for He:water ratio was 4.4:1, 3:1 and 3.4:1; shaking time was 13, 12 and 13 min; and standing time was 63, 17 and 108 min, respectively. The headspace equilibration method needs to be harmonised to ensure comparability between studies. The experiment reveals that He:water ratio 3:1 and shaking time 13 min give better estimation of dissolved gases than any lower or higher ratios and shaking times. The standing time 63, 17 and 108 min should be applied for N(2)O, CO(2) and CH(4), respectively. Copyright © 2012. Published by Elsevier Ltd.

  17. Sensitive high performance liquid chromatographic method for the ...

    African Journals Online (AJOL)

    A new simple, sensitive, cost-effective and reproducible high performance liquid chromatographic (HPLC) method for the determination of proguanil (PG) and its metabolites, cycloguanil (CG) and 4-chlorophenylbiguanide (4-CPB) in urine and plasma is described. The extraction procedure is a simple three-step process ...

  18. Development and Validation of a Liquid Chromatographic Method ...

    African Journals Online (AJOL)

    A liquid chromatographic method for the simultaneous determination of six human immunodeficiency virus (HIV) protease inhibitors, indinavir, saquinavir, ritonavir, amprenavir, nelfinavir and lopinavir, was developed and validated. Optimal separation was achieved on a PLRP-S 100 Å, 250 x 4.6 mm I.D. column maintained ...

  19. A novel method for the determination of adsorption partition coefficients of minor gases in a shale sample by headspace gas chromatography.

    Science.gov (United States)

    Zhang, Chun-Yun; Hu, Hui-Chao; Chai, Xin-Sheng; Pan, Lei; Xiao, Xian-Ming

    2013-10-04

    A novel method has been developed for the determination of adsorption partition coefficient (Kd) of minor gases in shale. The method uses samples of two different sizes (masses) of the same material, from which the partition coefficient of the gas can be determined from two independent headspace gas chromatographic (HS-GC) measurements. The equilibrium for the model gas (ethane) was achieved in 5h at 120°C. The method also involves establishing an equation based on the Kd at higher equilibrium temperature, from which the Kd at lower temperature can be calculated. Although the HS-GC method requires some time and effort, it is simpler and quicker than the isothermal adsorption method that is in widespread use today. As a result, the method is simple and practical and can be a valuable tool for shale gas-related research and applications. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Method Development for Container Closure Integrity Evaluation via Headspace Gas Ingress by Using Frequency Modulation Spectroscopy.

    Science.gov (United States)

    Victor, Ken G; Levac, Lauren; Timmins, Michael; Veale, James

    2017-01-01

    USP Section 3.5 states that "A deterministic leak test method having the ability to detect leaks at the product's maximum allowable leakage limit is preferred when establishing the inherent integrity of a container-closure system." Ideally, container closure integrity of parenteral packaging would be evaluated by measuring a physical property that is sensitive to the presence of any package defect that breaches package integrity by increasing its leakage above its maximum allowable leakage limit. The primary goals of the work presented herein were to demonstrate the viability of the nondestructive, deterministic method known as laser-based gas headspace analysis for evaluating container closure integrity and to provide a physical model for predicting leak rates for a variety of container volumes, headspace conditions, and defect sizes. The results demonstrate that laser-based headspace analysis provides sensitive, accurate, and reproducible measurements of the gas ingress into glass vial-stopper package assemblies that are under either diffusive or effusive leak conditions. Two different types of positive controls were examined. First, laser-drilled micro-holes in thin metal disks that were crimped on top of 15R glass vials served as positive controls with a well-characterized defect geometry. For these, a strong correlation was observed between the measured ingress parameter and the size of the defect for both diffusive and effusive conditions. Second, laser-drilled holes in the wall of glass vials served as controls that more closely simulate real-world defects. Due to their complex defect geometries, their diffusive and effusive ingress parameters did not necessarily correlate; this is an important observation that has significant implications for standardizing the characterization of container defects. Regardless, laser-based headspace analysis could readily differentiate positive and negative controls for all leak conditions, and the results provide a guide

  1. Multiple headspace extraction for gas detection in ionic liquids.

    Science.gov (United States)

    Müller, D; Fühl, M; Pinkwart, K; Baltes, N

    2014-10-16

    In this study multiple headspace extraction was used for the first time to measure the saturation concentration of carbon monoxide and oxygen in various ionic liquids (ILs). Many processes in ILs involve the reaction of gases so that the reactant solubility is not a mere characteristical parameter, but understanding the solubility of gases in ILs is required for assessing the feasibility of possible applications. Multiple headspace extraction has proofed to be a powerful tool to obtain solubilities in good accordance with literature data. The measured saturation concentration for carbon monoxide and oxygen in ILs based on rarely researched tetracyanoborates and other anions was in the range of 1.5-6.5mmol/L. The great advantage of multiple headspace extraction is that it is a nonexpensive method that can be realised in most analytical laboratories by combination of a simple gas chromatograph and an eligible headspace injector. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Development of a new sorptive extraction method based on simultaneous direct and headspace sampling modes for the screening of polycyclic aromatic hydrocarbons in water samples.

    Science.gov (United States)

    Triñanes, Sara; Pena, Ma Teresa; Casais, Ma Carmen; Mejuto, Ma Carmen

    2015-01-01

    A new straightforward and inexpensive sample screening method for both EPA and EU priority polycyclic aromatic hydrocarbons (PAHs) in water has been developed. The method is based on combined direct immersion and headspace (DIHS) sorptive extraction, using low-cost disposable material, coupled to ultraperformance liquid chromatography with fluorescence and UV detection (UPLC-FD-UV). Extraction parameters, such as the sampling mode, extraction time and ionic strength were investigated in detail and optimized. Under optimized conditions, water samples (16 mL) were concentrated in silicone disks by headspace (HS) and direct immersion (DI) modes simultaneously, at room temperature for 9h for the majority of the 24 studied compounds. Ultrasound-assisted desorption of extracted analytes in acetonitrile was carried out also at room temperature. The optimized chromatographic method provided a good linearity (R≥0.9991) and a broad linear range for all studied PAHs. The proposed analytical procedure exhibited a good precision level with relative standard deviations below 15% for all analytes. Quantification limits between 0.7 and 2.3 µg L(-1) and 0.16 and 3.90 ng L(-1) were obtained for compounds analyzed by UV (acenaphtylene, cyclopenta[c,d]pyrene and benzo[j]fluoranthene) and fluorescence, respectively. Finally, the proposed method was applied to the determination of PAHs in different real tap, river and wastewater samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Development and Validation of a Method for Alcohol Analysis in Brain Tissue by Headspace Gas Chromatography with Flame Ionization Detector.

    Science.gov (United States)

    Chun, Hao-Jung; Poklis, Justin L; Poklis, Alphonse; Wolf, Carl E

    2016-10-01

    Ethanol is the most widely used and abused drug. While blood is the preferred specimen for analysis, tissue specimens such as brain serve as alternative specimens for alcohol analysis in post-mortem cases where blood is unavailable or contaminated. A method was developed using headspace gas chromatography with flame ionization detection (HS-GC-FID) for the detection and quantification of ethanol, acetone, isopropanol, methanol and n-propanol in brain tissue specimens. Unfixed volatile-free brain tissue specimens were obtained from the Department of Pathology at Virginia Commonwealth University. Calibrators and controls were prepared from 4-fold diluted homogenates of these brain tissue specimens, and were analyzed using t-butanol as the internal standard. The chromatographic separation was performed with a Restek BAC2 column. A linear calibration was generated for all analytes (mean r(2) > 0.9992) with the limits of detection and quantification of 100-110 mg/kg. Matrix effect from the brain tissue was determined by comparing the slopes of matrix prepared calibration curves with those of aqueous calibration curves; no significant differences were observed for ethanol, acetone, isopropanol, methanol and n-propanol. The bias and the CVs for all volatile controls were ≤10%. The method was also evaluated for carryover, selectivity, interferences, bench-top stability and freeze-thaw stability. The HS-GC-FID method was determined to be reliable and robust for the analysis of ethanol, acetone, isopropanol, methanol and n-propanol concentrations in brain tissue, effectively expanding the specimen options for post-mortem alcohol analysis. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  4. Method detection limit determination and application of a convenient headspace analysis method for methyl tert-butyl ether in water.

    Science.gov (United States)

    O'Neill, Dennis T; Rochette, Elizabeth A; Ramsey, Philip J

    2002-11-15

    Methyl tert-butyl ether (MTBE) is a common groundwater contaminant, introduced to the environment by leaking petroleum storage tanks, urban runoff, and motorized watercraft. In this study. a simplified (static) headspace analysis method was adapted for determination of MTBE in water samples and soil water extracts. The MDL of the headspace method was calculated to be 2.0 microg L(-1) by the EPA single-concentration design method(1) and 1.2 microg L(-1) by a calibration method developed by Hubaux and Vos (Hubaux, A.; Vos, G. Anal. Chem. 1970,42, 849-855). The MDL calculated with the Hubaux and Vos method was favored because it considers both a true positive and a false positive. The static headspace method was applied to analysis of a tap water sample and a monitoring well sample from a gasoline service station, a river sample, and aqueous extracts from soil excavated during removal of a leaking underground storage tank (LUST). The water samples examined in this study had MTTBE concentrations ranging from 6 to 19 microg L(-1). Aqueous extracts of a soil sample taken from the LUST site had 8 microg L(-1) MTBE.

  5. Development of a method utilizing drum headspace VOC concentration as a waste characterization tool

    Energy Technology Data Exchange (ETDEWEB)

    Liekhus, K.J.; Gresham, G.L.; Peterson, E.S.; Rae, C.; Connolly, M.J.

    1994-12-31

    Pretest waste characterization for the bin-scale tests at the Waste Isolation Pilot Plant (WIPP) required sampling for volatile organic compounds (VOCS) from within transuranic (TRU) waste drums. Although the bin-scale tests have been postponed, the development and demonstration of accurate waste characterization methods continues. The objectives of extensive sampling of waste drums are to obtain a representative sample from each layer of confinement to identify volatile and gaseous constituents, verify process knowledge of the drum contents, and demonstrate compliance with regulatory requirements. A method to estimate the VOC concentration between layers of confinement from a single headspace sample collected beneath the drum filter of a vented waste drum is investigated. This method of characterizing the void space within a drum could eventually lead to a significant reduction in sampling time and cost. A model based on fundamental principles of transport phenomena is developed to estimate the VOC concentration throughout a waste drum based on the knowledge of the transport properties and the measured drum headspace VOC concentration. Model and experimental results are compared.

  6. Liquid Chromatographic Method for Determination of Nisoldipine from Pharmaceutical Samples

    Directory of Open Access Journals (Sweden)

    Amit Gupta

    2010-01-01

    Full Text Available A simple and specific high performance thin layer chromatographic method was developed and validated for the determination of nisoldipine from tablet dosage form. The method was carried out at 320 nm after extraction of drug in methanol. The method uses aluminum plates pre-coated with silica gel 60F-254 as stationary phase and cyclohexane-ethyl acetate-toluene (3:3:4, v/v/v as mobile phase. Linearity was established over a range of 400-2400 ng per zone. Both peak area ratio and peak height ratio showed acceptable correlation coefficient i.e. more than 0.99. However we used peak area for validation purpose. Intra-day and inter-day precision was determined and found to have less than 6.0 % RSD.

  7. Measurement of aqueous Henry's law constants for oxygenates and aromatics found in gasolines by the static headspace method

    Science.gov (United States)

    Miller; Stuart

    2000-02-01

    A simple equilibrium vessel made from a large stopcock was used in conjunction with the static headspace method to measure the aqueous Henry's law constants for methyl tert-butyl ether (MTBE) and other potential oxygenates as well as certain of the aromatics found in gasoline. The present method involves using only one aqueous solution whose concentration is not necessarily known. The only quantity that must be known is the phase ratio. Plotting a series of peak areas of the analyte in the headspace after each equilibrium change against the initial peak area of the analyte found in the headspace leads to a linear relationship whose slope is dependent on the analyte's unitless Henry's law constant and the phase ratio. This new method is found to yield unitless aqueous Henry's law constants in the range from 0.02 to 0.2, which are especially applicable to the oxygenates and aromatics found in gasolines.

  8. Ranking the significance of fermentation conditions on the volatile organic compounds of Tuber melanosporum fermentation system by combination of head-space solid phase microextraction and chromatographic fingerprint similarity analysis.

    Science.gov (United States)

    Li, Dao-Cheng; Liu, Rui-Sang; Li, Hong-Mei; Yuan, Zhan-Peng; Chen, Tao; Tang, Ya-Jie

    2014-03-01

    Tuber melanosporum is highly appreciated in culinary contexts due to its unique and characteristic aroma. T. melanosporum fermentation has been established as a promising alternative for fruiting bodies to produce volatile organic compounds (VOCs). In this work, a technique using a combination of chromatographic fingerprint similarity analysis, head-space solid phase microextraction and gas chromatography was developed to rank the significance of fermentation conditions on the VOCs profile during T. melanosporum fermentation. Omission tests indicated that the absence of major carbon source (i.e., sucrose) in the fermentation media had the most significant effect on the profile of VOCs, followed by the absence of yeast extract or peptone. Consideration of the culture conditions revealed that VOCs produced was the most significantly affected by temperature. These results indicated that it is possible to adjust the aroma of truffles via fermentation process control.

  9. Headspace solid-phase microextraction-gas chromatographic-time-of-flight mass spectrometric methodology for geographical origin verification of coffee.

    Science.gov (United States)

    Risticevic, Sanja; Carasek, Eduardo; Pawliszyn, Janusz

    2008-06-09

    Increasing consumer awareness of food safety issues requires the development of highly sophisticated techniques for the authentication of food commodities. The food products targeted for falsification are either products of high commercial value or those produced in large quantities. For this reason, the present investigation is directed towards the characterization of coffee samples according to the geographical origin. The conducted research involves the development of a rapid headspace solid-phase microextraction (HS-SPME)-gas chromatography-time-of-flight mass spectrometry (GC-TOFMS) method that is utilized for the verification of geographical origin traceability of coffee samples. As opposed to the utilization of traditional univariate optimization methods, the current study employs the application of multivariate experimental designs to the optimization of extraction-influencing parameters. Hence, the two-level full factorial first-order design aided in the identification of two influential variables: extraction time and sample temperature. The optimum set of conditions for the two variables was 12 min and 55 degrees C, respectively, as directed by utilization of Doehlert matrix and response surface methodology. The high-throughput automated SPME procedure was completed by implementing a single divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) 50/30 microm metal fiber with excellent durability properties ensuring the completion of overall sequence of coffee samples. The utilization of high-speed TOFMS instrument ensured the completion of one GC-MS run of a complex coffee sample in 7.9 min and the complete list of benefits provided by ChromaTOF software including fully automated background subtraction, baseline correction, peak find and mass spectral deconvolution algorithms was exploited during the data evaluation procedure. The combination of the retention index (RI) system using C(8)-C(40) alkanes and the mass spectral library search was utilized

  10. Headspace Theater: An Innovative Method for Experiential Learning of Psychiatric Symptomatology Using Modified Role-Playing and Improvisational Theater Techniques

    Science.gov (United States)

    Ballon, Bruce C.; Silver, Ivan; Fidler, Donald

    2007-01-01

    Objective: Headspace Theater has been developed to allow small group learning of psychiatric conditions by creating role-play situations in which participants are placed in a scenario that simulates the experience of the condition. Method: The authors conducted a literature review of role-playing techniques, interactive teaching, and experiential…

  11. Analytical validation applied to simultaneous determination of solvents dichloromethane (DCM), methyl isobutyl ketone (MIBK), tetrahydrofuran (THF) and toluene (TOL) in urine by headspace extraction and injection on chromatographic system with a flame ionization detector

    Science.gov (United States)

    Muna, E. D. M.; Pereira, R. P.

    2016-07-01

    The determination of the volatile organic solvents dichloromethane (DCM), methyl isobutyl ketone (MIBK), tetrahydrofuran (THF) and toluene (TOL) is applied on toxicological monitoring of employees in various industrial activities. The gas chromatography technique with flame ionization detector and headspace injection system has been applied. The analytical procedure developed allows the simultaneous determination of the above-mentioned solvents and the accuracy of the method was tested following the INMETRO guidelines through the DOQ-CGRE 008 Rev.04-July/2011.

  12. Extraction, chromatographic and mass spectrometric methods for lipid analysis.

    Science.gov (United States)

    Pati, Sumitra; Nie, Ben; Arnold, Robert D; Cummings, Brian S

    2016-05-01

    Lipids make up a diverse subset of biomolecules that are responsible for mediating a variety of structural and functional properties as well as modulating cellular functions such as trafficking, regulation of membrane proteins and subcellular compartmentalization. In particular, phospholipids are the main constituents of biological membranes and play major roles in cellular processes like transmembrane signaling and structural dynamics. The chemical and structural variety of lipids makes analysis using a single experimental approach quite challenging. Research in the field relies on the use of multiple techniques to detect and quantify components of cellular lipidomes as well as determine structural features and cellular organization. Understanding these features can allow researchers to elucidate the biochemical mechanisms by which lipid-lipid and/or lipid-protein interactions take place within the conditions of study. Herein, we provide an overview of essential methods for the examination of lipids, including extraction methods, chromatographic techniques and approaches for mass spectrometric analysis. Copyright © 2016 John Wiley & Sons, Ltd.

  13. Comparison of dynamic headspace methods used for the analysis of the volatile composition of Spanish PDO ewe's raw milk cheeses

    OpenAIRE

    Javier R. Barron, Luis; Redondo, Yolanda; Ortigosa, María; Carbonell, María; García, Susana; Torre, Paloma; De Renobales, Mertxe; Fernández-García, Estrella

    2005-01-01

    International audience; Different dynamic headspace (DHS) methods used for determination of volatile compounds in cheeses were compared. Three different laboratories using gas chromatography coupled to mass spectrometry carried out the analyses of volatile compounds of Spanish Protected Designation of Origin ewe's raw milk cheeses. One laboratory used "purge and trap" (P&T) with thermal desorption of the trap by ultrafast microwave heating (MWH) and the other two laboratories used P&T with th...

  14. Development and Validation of a Method for Alcohol Analysis in Brain Tissue by Headspace Gas Chromatography with Flame Ionization Detector

    OpenAIRE

    Chun, Hao-Jung; Poklis, Justin L.; Poklis, Alphonse; Wolf, Carl E.

    2016-01-01

    Ethanol is the most widely used and abused drug. While blood is the preferred specimen for analysis, tissue specimens such as brain serve as alternative specimens for alcohol analysis in post-mortem cases where blood is unavailable or contaminated. A method was developed using headspace gas chromatography with flame ionization detection (HS-GC-FID) for the detection and quantification of ethanol, acetone, isopropanol, methanol and n-propanol in brain tissue specimens. Unfixed volatile-free br...

  15. A headspace SPME-GC-ECD method suitable for determination of chlorophenols in water samples.

    Science.gov (United States)

    de Morais, Paulo; Stoichev, Teodor; Basto, M Clara P; Carvalho, Pedro N; Vasconcelos, M Teresa S D

    2011-03-01

    A headspace solid phase microextraction coupled to gas chromatography with electron capture detector (HS-SPME-GC-ECD) method was optimized for the determination of seven chlorophenols (CPs) with different levels of chlorination. This is the first time that HS-SPME-GC-ECD with acetylation of the analytes is used for the simultaneous determination of CPs in water samples. The influence of fibre type, derivatization conditions, salt addition, temperature and time of extraction and temperature of desorption was checked. Possible sources of contamination and analyte losses were considered. The best results were obtained with the polydimethylsiloxane/divinylbenzene fibre, derivatization by acetylation using 100 μL of acetic anhydride and 0.1 g of anhydrous sodium carbonate per 10 mL of sample, salt addition of 100 g L(-1) sodium chloride, extraction at 70 °C for 60 min and desorption in the GC injector at 260 °C for 6 min. The limits of detection (LOD) for monochlorophenols were 12 and 122 ng L(-1) for 2-chlorophenol and 4-chlorophenol, respectively. For polychlorinated CPs, the LODs were lower than 6 ng L(-1), values similar to the existing methods that use SPME with derivatization for CPs determination in water samples. The method is suitable for the determination of CPs in most environmental aqueous samples. Repeatability and reproducibility were less than 16.8% and 11.7%, respectively. The optimized method was successfully applied for the analysis of waters with complex matrices such as river and estuarine water samples.

  16. Chromatographic Methods for the Analysis of Polyphenols in Wines

    Directory of Open Access Journals (Sweden)

    Medić-Šarić, M.

    2009-03-01

    Full Text Available Wine is an excellent source of various classes of polyphenols, including phenolic acids, flavonoids, and trihydroxystilbene resveratrol (Fig.1. Polyphenols play a major role in wine quality since they contribute to the sensory characteristics of wine, particularly color and astringency. A recent interest in these substances has been stimulated by abundant evidence of their beneficial effects on human health, such as anticarcinogenic, antiinflamatory and antimicrobial activities. Therefore, numerous studies have been performed in the attempt to analyze polyphenols in wine. This paper reviews the current advances in the determination of polyphenols in wine by the major chromatographic techniques such as thin-layer chromatography (TLC and high-performance liquid chromatography (HPLC.The great complexity of the polyphenolic content of wine and the difficulty in obtaining some of the standards usually require sample preparation before analysis. Two methods for sample preparation, liquid-liquid extraction and solid-phase extraction, are most commonly applied. Hydrolysis is applied frequently, but not exclusively, to remove the sugar moieties from glycosides.TLC on silica gel plates is useful for the rapid and low-cost separation and identification of the polyphenols present in wine (Fig. 2. Densitometric quantitative analysis of polyphenols in wine extracts is usually performed by scanning the TLC plates with UV light at wavelengths of 350–365 nm or 250–260 nm (Fig. 3. For the evaluation of the most efficient mobile phase and an optimal choice of the combination of two or more mobile phases, two methods may be applied: information theory and numerical taxonomy. HPLC currently represents the most popular technique for the analysis of polyphenols in wine. For this purpose, a reversed-phase HPLC method that uses gradient elution with binary elution system is usually employed. Routine detection is based on measurement of UV-Vis absorption with a diode

  17. A generic static headspace gas chromatography method for determination of residual solvents in drug substance.

    Science.gov (United States)

    Cheng, Chang; Liu, Shaorong; Mueller, Bradford J; Yan, Zimeng

    2010-10-08

    In order to increase productivity of drug analysis in the pharmaceutical industry, an efficient and sensitive generic static headspace gas chromatography (HSGC) method was successfully developed and validated for the determination of 44 classes 2 and 3 solvents of International Conference of Harmonization (ICH) guideline Q3C, as residual solvents in drug substance. In order to increase the method sensitivity and efficiency in sample equilibration, dimethylsulfoxide (DMSO) was selected as the sample diluent based on its high capacity of dissolving drug substance, stability and high boiling point. The HS sample equilibration temperature and equilibration time are assessed in ranges of 125-150°C and 8-15 min, respectively. The results indicate that the residual solvents in 200mg of drug substance can be equilibrated efficiently in HS sampler at 140°C for 10 min. The GC parameters, e.g. sample split ratio, carrier flow rate and oven temperature gradient are manipulated to enhance the method sensitivity and separation efficiency. The two-stage gradient GC run from 35 to 240°C, using an Agilent DB-624 capillary column (30 m long, 0.32 mm I.D., 1.8 μm film thickness), is suitable to determine 44 ICH classes 2 and 3 solvents in 30 min. The method validation results indicate that the method is accurate, precise, linear and sensitive for solvents assessed. The recoveries of most of these solvents from four drug substances are greater than 80% within the method determination ranges. However, this method is not suitable for the 10 remaining ICH classes 2 and 3 solvents, because they are too polar (e.g. formic acid and acidic acid), or have boiling points higher than 150°C, (e.g. anisol and cumene). In comparison with the previous published methods, this method has a much shorter sample equilibration time, a better separation for many solvents, a higher sensitivity and a broader concentration range. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. Factors controlling headspace pressure in a manual manometric BMP method can be used to produce a methane output comparable to AMPTS.

    Science.gov (United States)

    Himanshu, H; Voelklein, M A; Murphy, J D; Grant, J; O'Kiely, P

    2017-08-01

    The manual manometric biochemical methane potential (mBMP) test uses the increase in pressure to calculate the gas produced. This gas production may be affected by the headspace volume in the incubation bottle and by the overhead pressure measurement and release (OHPMR) frequency. The biogas and methane yields of cellulose, barley, silage and slurry were compared with three incubation bottle headspace volumes (50, 90 and 180ml; constant 70ml total medium) and four OHPMR frequencies (daily, each third day, weekly and solely at the end of experiment). The methane yields of barley, silage and slurry were compared with those from an automated volumetric method (AMPTS). Headspace volume and OHPMR frequency effects on biogas yield were mediated mainly through headspace pressure, with the latter having a negative effect on the biogas yield measured and relatively little effect on methane yield. Two mBMP treatments produced methane yields equivalent to AMPTS. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Determination of chlorinated volatile organic compounds in polyamine epichlorohydrin solution by headspace gas chromatography.

    Science.gov (United States)

    Yan, Ning; Wan, Xiao-Fang; Chai, Xin-Sheng; Chen, Run-Quan

    2017-05-05

    This study demonstrated a headspace gas chromatographic (HS-GC) method for the determination of residual epichlorohydrin (ECH) and the by-product 1,3-dichloro-2-propanol (DCP) in polyamine epichlorohydrin (PAE) solution. It was based on the vapor-liquid phase equilibrium of these analytes at 60°C for 30min in a closed headspace sample vial before GC measurement. It was found that matrix of the PAE solution had the effect on the headspace equilibrium of these species and therefore a standard addition must be applied in the method validation. The results showed that the present method has a good measurement precision (RSD volatile organic compounds in the commercial PAE resin solutions. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Development of a simple analytical method for determining trihalomethanes in beer using a headspace solid-phase microextraction technique

    Directory of Open Access Journals (Sweden)

    Marcel Silveira dos Santos

    2013-01-01

    Full Text Available We developed a simple, rapid, and solventless method for analyzing trihalomethanes in beer samples using headspace solid-phase microextraction. The effects of varying experimental parameters, such as extraction temperature and time, addition of sodium chloride, and agitation speed, on extraction yield were studied using a univariate experimental design. Limits of detection between 0.22 and 0.46 µg L- 1 and wide linear ranges were achieved for trihalomethanes. We measured the trihalomethane recoveries and precision (as the standard deviation of repeat measurements and demonstrated the applicability of the proposed method by analyzing 32 beer samples.

  1. Headspace microdrop analysis--an alternative test method for gasoline diluent and benzene, toluene, ethylbenzene and xylenes in used engine oils.

    Science.gov (United States)

    Kokosa, John M; Przyjazny, Andrzej

    2003-01-03

    The primary standard test method used for the determination of gasoline diluent in used engine oils is method D 3525-93 of the American Society for Testing and Materials (ASTM), which involves direct injection of used oil onto a packed GC column and flame ionization detection. Recently, we have utilized a new headspace sampling method: headspace solvent microextraction (HSM), for GC and GC-MS analysis of gasoline diluent in used engine oils. High resolution capillary columns can be used without the necessity for the use of inlet cryogenic cooling or expensive sampling interfaces. This analytical method, which we generically refer to as headspace microdrop analysis yields results comparable to those obtained using the ASTM method, with the added benefit that it allows the quantification of individual volatile diluent components, including benzene, toluene, ethylbenzene and the xylenes.

  2. A pressure-affected headspace-gas chromatography method for determining calcium carbonate content in paper sample.

    Science.gov (United States)

    Dai, Yi; Yu, Zhen-Hua; Zhan, Jian-Bo; Chai, Xin-Sheng; Zhang, Shu-Xin; Xie, Wei-Qi; He, Liang

    2017-07-21

    The present work reports on the development of a pressure-affected based headspace (HS) analytical technique for the determination of calcium carbonate content in paper samples. By the acidification, the carbonate in the sample was converted to CO2 and released into the headspace of a closed vial and then measured by gas chromatography (GC). When the amount of carbonate in the sample is significant, the pressure created by the CO2 affects the accuracy of the method. However, the pressure also causes a change in the O2 signal in the HS-GC measurement, which is a change that can be used as an indirect measure of the carbonate in the sample. The results show that the present method has a good precision (the relative standard deviation<2.32%), and good accuracy (the relative differences compared to a reference method was<5.76%). Coupled with the fact that the method is simple, rapid, and accurate, it is suitable for a variety of applications that call for the analysis of high carbonate content in paper samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Validation of chromatographic methods: an experiment using HPLC and Green Chemistry in methylxanthines determination

    OpenAIRE

    Nádia Machado de Aragão; Márcia Cristina da Cunha Veloso; Jailson Bittencourt de Andrade

    2009-01-01

    The validation of analytical methods is an important step in quality control. The main objective of this study is to propose an HPLC experiment to verify the parameters of validation of chromatographic methods, based on green chemistry principles, which can be used in experimental courses of chemistry and related areas.

  4. Comparison of high-performance liquid chromatographic and thin-layer chromatographic methods for determination of aloin in herbal products containing Aloe vera.

    Science.gov (United States)

    Ramírez Durón, Rosalba; Ceniceros Almaguer, Lucía; Cavazos Rocha, Norma Cecilia; Silva Flores, Perla Giovanna; De Torres, Noemí Waksman

    2008-01-01

    Aloe vera is a medicinal plant used worldwide to treat a variety of conditions and, as such, has important commercial value. Aloin is a principal component of aloe vera leaves and is used for quality control of products containing it. A semiquantitative thin-layer chromatographic (TLC) method for determining the concentration of aloin in aloe-based products was validated. The results were similar to those of a validated high-performance liquid chromatographic method; therefore, TLC, which is a simple, sensitive, specific, rapid, and cheap method, may be ideal for use in any laboratory for routine analysis of commercial products containing aloe vera.

  5. [A combination of chromatographic analysis methods in determining narcotic analgesics in biological fluids].

    Science.gov (United States)

    Berezentsev, O M; Kliachko, Iu A; Nikulichev, D B; Nikulicheva, S I; Padalkina, V S

    1995-01-01

    A combination of instrumental chromatographic methods high pressure liquid chromatography in the isocratic mode and reverse phase thin-layer chromatography with densitometric ending on Russian Sorbton-RP-2 plates--is conducive to a fuller and more reliable identification of narcotic analgesics in biological fluids (blood and urine).

  6. Evaluation of coverage, retention patterns and selectivity of seven liquid chromatographic methods for metabolomics

    OpenAIRE

    Wernisch, Stefanie; Pennathur, Subramaniam

    2016-01-01

    Liquid chromatography-mass spectrometry (LC-MS)-based metabolomics studies require highly selective and efficient chromatographic techniques. Typically employed reversed-phase (RP) methods fail to target polar metabolites but the introduction of hydrophilic interaction liquid chromatography (HILIC) is slow due to perceived issues of reproducibility and ruggedness and a limited understanding of the complex retention mechanisms.

  7. Simple high-performance liquid chromatographic method to analyse megazol in human and rat plasma

    OpenAIRE

    Enanga, Bertin; Labat, Christian; Boudra, Hamid; Chauvière, G; Keita, M; Bouteille, B.; Dumas, Michel; Houin, Georges

    1997-01-01

    A simple and sensitive high-performance liquid chromatographic method has been developed to measure megazol in human plasma. The method was optimized and validated according to the Washington Concensus Conference on the Validation of Analytical Methods (V.P. Shah et al., Eur. J. Drug Metab. Pharmacokinet., 15 (1991) 249). The criteria of complete validation were specificity, linearity, precision, analytical recovery, dilution and stability. It involved extraction of the plasma with dichlorome...

  8. Comparison of two detection methods in thin layer chromatographic ...

    African Journals Online (AJOL)

    o-tolidine plus potassium iodide and photosynthesis inhibition detection methods were investigated for the analysis of three triazine herbicides (atrazine, ametryne, simazine) and two urea herbicides (diuron, metobromuron) in a coastal savanna soil using thin layer chromatography to compare the suitability of the two ...

  9. CHROMATOGRAPHIC METHODS IN THE ANALYSIS OF CHOLESTEROL AND RELATED LIPIDS

    NARCIS (Netherlands)

    HOVING, EB

    1995-01-01

    Methods using thin-layer chromatography, solid-phase extraction, gas chromatography, high-performance liquid chromatography and supercritical fluid chromatography are described for the analysis of single cholesterol, esterified and sulfated cholesterol, and for cholesterol in the context of other

  10. Development and validation of a thin layer chromatographic method ...

    African Journals Online (AJOL)

    The two drugs were satisfactorily resolved with mean Rf values of 0.04 ± 0.03 and 0.06 ± 0.07 for artesunate and amodiaquine, respectively. The accuracy and reliability of the method was assessed by evaluation of linearity (0.001 – 6.0 and 0.05 – 6.0 mg/ml for artesunate and amodiaquine), precision (intraday RSD 10.68 ...

  11. A novel thermodynamic state recursion method for description of nonideal nonlinear chromatographic process of frontal analysis.

    Science.gov (United States)

    Liu, Qian; OuYang, Liangfei; Liang, Heng; Li, Nan; Geng, Xindu

    2012-06-01

    A novel thermodynamic state recursion (TSR) method, which is based on nonequilibrium thermodynamic path described by the Lagrangian-Eulerian representation, is presented to simulate the whole chromatographic process of frontal analysis using the spatial distribution of solute bands in time series like as a series of images. TSR differs from the current numerical methods using the partial differential equations in Eulerian representation. The novel method is used to simulate the nonideal, nonlinear hydrophobic interaction chromatography (HIC) processes of lysozyme and myoglobin under the discrete complex boundary conditions. The results show that the simulated breakthrough curves agree well with the experimental ones. The apparent diffusion coefficient and the Langmuir isotherm parameters of the two proteins in HIC are obtained by the state recursion inverse method. Due to its the time domain and Markov characteristics, TSR is applicable to the design and online control of the nonlinear multicolumn chromatographic systems. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. A review of the extraction and chromatographic determination methods for the analysis of parabens.

    Science.gov (United States)

    Piao, Chunying; Chen, Ligang; Wang, Yu

    2014-10-15

    Parabens are a family of most widely used antimicrobial preservatives in food ingredients, cosmetic consumer products and pharmaceutical preparations. But several recent studies have cautioned that exposure to parabens may have more harmful consequences on animal and human health than what we realized previously, which made the analysis of parabens necessary. In this paper, we reviewed main sample preparation methods and chromatographic analysis methods proposed in formerly published works dealing with the analysis of parabens in different matrices. The sample preparation methods included ultrasonic assisted extraction, supercritical fluid extraction, pressurized liquid extraction, solid phase extraction, solid phase microextraction, liquid phase microextraction, dispersive liquid-liquid microextraction, stir bar sorptive extraction and matrix solid phase dispersion. The chromatographic analysis methods involved liquid chromatography, gas chromatography, and capillary electrophoresis. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Improved method and apparatus for chromatographic quantitative analysis

    Science.gov (United States)

    Fritz, J.S.; Gjerde, D.T.; Schmuckler, G.

    An improved apparatus and method are described for the quantitative analysis of a solution containing a plurality of anion species by ion exchange chromatography which utilizes a single element and a single ion exchange bed which does not require periodic regeneration. The solution containing the anions is added to an anion exchange resin bed which is a low capacity macroreticular polystyrene-divinylbenzene resin containing quarternary ammonium functional groups, and is eluted therefrom with a dilute solution of a low electrical conductance organic acid salt. As each anion species is eluted from the bed, it is quantitatively sensed by conventional detection means such as a conductivity cell.

  14. Freeze-thaw method improves the detection of volatile compounds in insects using Headspace Solid-Phase Microextraction (HS-SPME)

    Science.gov (United States)

    Headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography–mass spectrometry (GC-MS) is commonly used in analyzing insect volatiles. In order to improve the detection of volatiles in insects, a freeze-thaw method was applied to insect samples before the HS-SPME-GC-MS analysis. ...

  15. Development of immunoaffinity chromatographic method for Ara h 2 isolation.

    Science.gov (United States)

    Wu, Zhihua; Zhang, Ying; Zhan, Shaode; Lian, Jun; Zhao, Ruifang; Li, Kun; Tong, Ping; Li, Xin; Yang, Anshu; Chen, Hongbing

    2017-03-01

    Ara h 2 is considered a major allergen in peanut. Due to the difficulty of separation, Ara h 2 had not been fully studied. Immunoaffinity chromatography (IAC) column can separate target protein with high selectivity, which made it possible to purify Ara h 2 from different samples. In this study, IAC method was developed to purify Ara h 2 and its effect was evaluated. By coupling polyclonal antibody (pAb) on CNBr-activated Sepharose 4B, the column for specific extraction was constructed. The coupling efficiency of the IAC column was higher than 90%, which made the capacity of column reached 0.56 mg per 0.15 g medium (dry weight). The recovery of Ara h 2 ranged from 93% to 100% for different concentrations of pure Ara h 2 solutions in 15 min. After using a column 10 times, about 88% of the column capacity remained. When applied to extract Ara h 2 from raw peanut protein extract and boiled peanut protein extract, the IAC column could recovery 94% and 88% target protein from the mixture. SDS-PAGE and Western blotting analysis confirmed the purified protein was Ara h 2, its purity reached about 90%. Significantly, the IAC column could capture dimer of Ara h 2, which made it feasible to prepared derivative of protein after processing. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Detection of irradiated fruits and vegetables by gas-chromatographic methods and electron spin-resonance

    Energy Technology Data Exchange (ETDEWEB)

    Farag, S.E.A. (National Centre for Radiation Research and Technology, Cairo (Egypt))

    1993-01-01

    Gas chromatographic methods detected some hydrocarbons esp. 17:1, 16:2, 15:0 and 14:1 in irradiated, Avocado, Papaya, Mangoes with 0.75, 1.5, 3.0 kGy and Apricot with 0.5 and 3.0 kGy. The detection of hydrocarbons was clearly at high doses but the low doses need more sensitive conditions using Liquid-Liquid-Gas chromatographic method as used here. Using Electron Spin-Resonance, produce a specific signal from irradiated onion (dried leaves) as well as apricot (hard coat of kernels) after some weeks of irradiation process but not clear with the other foodstuffs. (orig.)

  17. Methyl bromide determination in selected foods by headspace technique.

    Science.gov (United States)

    Daft, J L

    1993-01-01

    A headspace method used earlier for determining methyl bromide (MB) in assorted nuts and peanut butters has been successfully applied to other foods that could potentially contain traces of this toxic fumigant. The foods tested include 63 off-the-shelf spices and seasonings, 83 table-ready items (grain-based, dried, or highly seasoned), 30 dried fruits and trail mixes, and 38 oil-based items (oil-seeds, cooking oils, or spicy oil-based dressings). Sample headspace gas is produced by blending < or = 50 g sample in 250 +/- 50 mL aqueous solution in a sealed 1000 mL blender cup. After equilibration at 25 degrees C, the headspace is sampled with a gas-tight syringe and injected into a dual column-dual detector gas chromatograph. One determination is made with a 20% OV-101 packed column and a 63Ni electron capture detector (ECD), the other with a GS-Q wide-bore capillary column and a Hall electrolytic conductivity detector (HECD). Of the approximately 200 samples tested, none contained detectable MB residue at a quantitation limit < 100 ng/g sample. All fortified samples yielded MB recovery. Samples were fortified at levels ranging from 78 to 3250 ng MB/g. Recoveries ranged from a mean high of 56% for spices and seasonings to a mean low of 30% for oil-based foods. The overall recovery and CV, including the results from assorted nuts and peanut butters, were 46 and 33%, respectively.

  18. Thermospray liquid chromatographic-mass spectrometric method for the analysis of metribuzin and its metabolites.

    Science.gov (United States)

    Parker, C E; Geeson, A V; Games, D E; Ramsey, E D; Abusteit, E O; Corbin, F T; Tomer, K B

    1988-04-22

    A thermospray liquid chromatographic-mass spectrometric (TSP LC-MS) method has been developed for the analysis of the herbicide metribuzin and its three major metabolites in plant tissue. Metribuzin and its metabolites exhibited widely varying sensitivities in positive-ion TSP, with metribuzin being the most sensitive and deaminated diketo metribuzin being the least sensitive. All four compounds of interest were detected in an extract of a soybean plant which had been treated with metribuzin.

  19. Quantification of anhydride groups in anhydride-based epoxy hardeners by reaction headspace gas chromatography.

    Science.gov (United States)

    Xie, Wei-Qi; Gong, Yi-Xian; Yu, Kong-Xian

    2017-06-01

    We demonstrate a reaction headspace gas chromatographic method for quantifying anhydride groups in anhydride-based epoxy hardeners. In this method, the conversion process of anhydride groups can be realized by two steps. In the first step, anhydride groups in anhydride-based epoxy hardeners completely reacted with water to form carboxyl groups. In the second step, the carboxyl groups reacted with sodium bicarbonate solution in a closed sample vial. After the complete reaction between the carboxyl groups and sodium bicarbonate, the CO2 formed from this reaction was then measured by headspace gas chromatography. The data showed that the reaction in the closed headspace vial can be completed in 15 min at 55°C, the relative standard deviation of the reaction headspace gas chromatography method in the precision test was less than 3.94%, the relative differences between the new method and a reference method were no more than 9.38%. The present reaction method is automated, efficient and can be a reliable tool for quantifying the anhydride groups in anhydride-based epoxy hardeners and related research. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Direct synthesis of nitrogen-doped graphene on platinum wire as a new fiber coating method for the solid-phase microextraction of BXes in water samples: Comparison of headspace and cold-fiber headspace modes.

    Science.gov (United States)

    Memarian, Elham; Hosseiny Davarani, Saied Saeed; Nojavan, Saeed; Movahed, Siyavash Kazemi

    2016-09-07

    In this work, a new solid-phase microextraction fiber was prepared based on nitrogen-doped graphene (N-doped G). Moreover, a new strategy was proposed to solve problems dealt in direct coating of N-doped G. For this purpose, first, Graphene oxide (GO) was coated on Pt wire by electrophoretic deposition method. Then, chemical reduction of coated GO to N-doped G was accomplished by hydrazine and NH3. The prepared fiber showed good mechanical and thermal stabilities. The obtained fiber was used in two different modes (conventional headspace solid-phase microextraction and cold-fiber headspace solid-phase microextraction (CF-HS-SPME)). Both modes were optimized and applied for the extraction of benzene and xylenes from different aqueous samples. All effective parameters including extraction time, salt content, stirring rate, and desorption time were optimized. The optimized CF-HS-SPME combined with GC-FID showed good limit of detections (LODs) (0.3-2.3 μg/L), limit of quantifications (LOQs) (1.0-7.0 μg/L) and linear ranges (1.0-5000 μg/L). The developed method was applied for the analysis of benzene and xylenes in rainwater and some wastewater samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Development and validation of a fast static headspace GC method for determination of residual solvents in permethrin.

    Science.gov (United States)

    Tian, Jingzhi; Rustum, Abu

    2016-09-05

    A fast static headspace gas chromatography (HS-GC) method was developed to separate all residual solvents present in commercial active pharmaceutical ingredient (API) batches of permethrin. A total of six residual solvents namely 2-methylpentane, 3-methylpentane, methylcyclopentane, n-hexane, cyclohexane and toluene were found in typical commercial batches of permethrin; and three of them are not in the list of ICH solvents. All six residual solvents were baseline separated in five minutes by the new method presented in this paper. The method was successfully validated as per International Conference on Harmonisation (ICH) guidelines. Evaluation of this method was conducted to separate 26 commonly used solvents in the manufacturing of various APIs, key intermediates of APIs and pharmaceutical excipients. The results of the evaluation demonstrated that this method can also be used as a general method to determine residual solvents in various APIs, intermediates and excipients that are used in pharmaceutical products. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. [Determination of olive oil content in olive blend oil by headspace gas chromatography-mass spectrometry].

    Science.gov (United States)

    Jiang, Wanfeng; Zhang, Ning; Zhang, Fengyan; Yang, Zhao

    2017-07-08

    A method for the determination of the content of olive oil in olive blend oil by headspace gas chromatography-mass spectrometry (SH-GC/MS) was established. The amount of the sample, the heating temperature, the heating time, the amount of injection, the injection mode and the chromatographic column were optimized. The characteristic compounds of olive oil were found by chemometric method. A sample of 1.0 g was placed in a 20 mL headspace flask, and heated at 180℃ for 2700 s. Then, 1.0 mL headspace gas was taken into the instrument. An HP-88 chromatographic column was used for the separation and the analysis was performed by GC/MS. The results showed that the linear range was 0-100%(olive oil content). The linear correlation coefficient (r2) was more than 0.995, and the limits of detection were 1.26%-2.13%. The deviations of olive oil contents in the olive blend oil were from -0.65% to 1.02%, with the relative deviations from -1.3% to 6.8% and the relative standard deviations from 1.18% to 4.26% (n=6). The method is simple, rapid, environment friendly, sensitive and accurate. It is suitable for the determination of the content of olive oil in olive blend oil.

  3. A rapid chromatographic method for quality control of technetium-99m-bicisate.

    Science.gov (United States)

    Amin, K C; Saha, G B; Go, R T

    1997-03-01

    The purpose of this work was to develop a simple and rapid method to determine the radiochemical purity of 99mTc-bicisate. A rapid paper chromatographic (PC) method was developed to determine the radiochemical purity of 99mTc-bicisate and compare the results with those of the manufacturer's recommended method. The present PC method included Whatman 3MM paper as the solid phase and ethyl acetate as the solvent. The time for chromatography by this technique was 4-5 min compared to about 23 min by the manufacturer's method. The Rf value of 99mTc-bicisate (Rf = 0.9-1.0) was widely different from those of 99mTcO4- and reduced 99mTc (Rf = 0.0 for both) so the chromatographic strip after development could be readily cut into two segments, in order to determine the labeling yield. No significant difference in labeling yields was found between the present method and the manufacturer's method. The PC method using Whatman 3MM paper and ethyl acetate is a simple and fast technique to determine the radiochemical purity of 99mTc-bicisate and may be substituted for the manufacturer's recommended method to save time.

  4. Development of a Direct Headspace Collection Method from Arabidopsis Seedlings Using HS-SPME-GC-TOF-MS Analysis

    Science.gov (United States)

    Kusano, Miyako; Iizuka, Yumiko; Kobayashi, Makoto; Fukushima, Atsushi; Saito, Kazuki

    2013-01-01

    Plants produce various volatile organic compounds (VOCs), which are thought to be a crucial factor in their interactions with harmful insects, plants and animals. Composition of VOCs may differ when plants are grown under different nutrient conditions, i.e., macronutrient-deficient conditions. However, in plants, relationships between macronutrient assimilation and VOC composition remain unclear. In order to identify the kinds of VOCs that can be emitted when plants are grown under various environmental conditions, we established a conventional method for VOC profiling in Arabidopsis thaliana (Arabidopsis) involving headspace-solid-phase microextraction-gas chromatography-time-of-flight-mass spectrometry (HS-SPME-GC-TOF-MS). We grew Arabidopsis seedlings in an HS vial to directly perform HS analysis. To maximize the analytical performance of VOCs, we optimized the extraction method and the analytical conditions of HP-SPME-GC-TOF-MS. Using the optimized method, we conducted VOC profiling of Arabidopsis seedlings, which were grown under two different nutrition conditions, nutrition-rich and nutrition-deficient conditions. The VOC profiles clearly showed a distinct pattern with respect to each condition. This study suggests that HS-SPME-GC-TOF-MS analysis has immense potential to detect changes in the levels of VOCs in not only Arabidopsis, but other plants grown under various environmental conditions. PMID:24957989

  5. Development of a Direct Headspace Collection Method from Arabidopsis Seedlings Using HS-SPME-GC-TOF-MS Analysis

    Directory of Open Access Journals (Sweden)

    Kazuki Saito

    2013-04-01

    Full Text Available Plants produce various volatile organic compounds (VOCs, which are thought to be a crucial factor in their interactions with harmful insects, plants and animals. Composition of VOCs may differ when plants are grown under different nutrient conditions, i.e., macronutrient-deficient conditions. However, in plants, relationships between macronutrient assimilation and VOC composition remain unclear. In order to identify the kinds of VOCs that can be emitted when plants are grown under various environmental conditions, we established a conventional method for VOC profiling in Arabidopsis thaliana (Arabidopsis involving headspace-solid-phase microextraction-gas chromatography-time-of-flight-mass spectrometry (HS-SPME-GC-TOF-MS. We grew Arabidopsis seedlings in an HS vial to directly perform HS analysis. To maximize the analytical performance of VOCs, we optimized the extraction method and the analytical conditions of HP-SPME-GC-TOF-MS. Using the optimized method, we conducted VOC profiling of Arabidopsis seedlings, which were grown under two different nutrition conditions, nutrition-rich and nutrition-deficient conditions. The VOC profiles clearly showed a distinct pattern with respect to each condition. This study suggests that HS-SPME-GC-TOF-MS analysis has immense potential to detect changes in the levels of VOCs in not only Arabidopsis, but other plants grown under various environmental conditions.

  6. Validated chromatographic and spectrophotometric methods for analysis of some amoebicide drugs in their combined pharmaceutical preparation.

    Science.gov (United States)

    Abdelaleem, Eglal Adelhamid; Abdelwahab, Nada Sayed

    2013-01-01

    This work is concerned with development and validation of chromatographic and spectrophotometric methods for analysis of mebeverine HCl (MEH), diloxanide furoate (DF) and metronidazole (MET) in Dimetrol® tablets - spectrophotometric and RP-HPLC methods using UV detection. The developed spectrophotometric methods depend on determination of MEH and DF in the combined dosage form using the successive derivative ratio spectra method which depends on derivatization of the obtained ratio spectra in two steps using methanol as a solvent and measuring MEH at 226.4-232.2 nm (peak to peak) and DF at 260.6-264.8 nm (peak to peak). While MET concentrations were determined using first derivative (1D) at λ = 327 nm using the same solvent. The chromatographic method depends on HPLC separation on ODS column and elution with a mobile phase consisting water: methanol: triethylamine (25: 75: 0.5, by volume, orthophosphoric acid to pH =4). Pumping the mobile phase at 0.7 ml min-1 with UV at 230 nm. Factors affecting the developed methods were studied and optimized, moreover, they have been validated as per ICH guideline and the results demonstrated that the suggested methods are reproducible, reliable and can be applied for routine use with short time of analysis. Statistical analysis of the two developed methods with each other using F and student's-t tests showed no significant difference.

  7. Validation of a headspace trap gas chromatography and mass spectrometry method for the quantitative analysis of volatile compounds from degraded rapeseed oil.

    Science.gov (United States)

    Sghaier, Lilia; Cordella, Christophe B Y; Rutledge, Douglas N; Watiez, Mickaël; Breton, Sylvie; Sassiat, Patrick; Thiebaut, Didier; Vial, Jérôme

    2016-05-01

    Due to lipid oxidation, off-flavors, characterized by a fishy odor, are emitted during the heating of rapeseed oil in a fryer and affect the flavor of rapeseed oil even at low concentrations. Thus, there is a need for analytical methods to identify and quantify these products. To study the headspace composition of degraded rapeseed oil, and more specifically the compounds responsible for the fishy odor, a headspace trap gas chromatography with mass spectrometry method was developed and validated. Six volatile compounds formed during the degradation of rapeseed oil were quantified: 1-penten-3-one, (Z)-4-heptenal, hexanal, nonanal, (E,E)-heptadienal, and (E)-2-heptenal. Validation using accuracy profiles allowed us to determine the valid ranges of concentrations for each compound, with acceptance limits of 40% and tolerance limits of 80%. This method was then successfully applied to real samples of degraded oils. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Validation of a headspace GC method for the analysis of a pyrolytic product of methamphetamine in urine.

    Science.gov (United States)

    Shakleya, Diaa M; Kraner, James C; Clay, David J; Callery, Patrick S; Bell, Suzanne C

    2006-10-01

    A method has been developed and validated using headspace GC-FID for the identification of 1-phenylpropene in urine. This compound is a pyrolytic product of methamphetamine that has been previously proposed as a marker for smoked methamphetamine. The instrumentation used is the same as employed for blood alcohol determination. The extraction-free procedure is rapid, simple, and quantitative using 2-phenylpropene as the internal standard. The method was validated for linearity over a range of 0.1-20 microg/mL with a limit of detection of 0.05 microg/mL, limit of quantification of 0.1 microg/mL, interday accuracy within 3.2 to -5.3%, intraday accuracy better than 7.5%, interday precision of 7.5 to 10.7%, intraday precision of 2 to 8.6%, and recovery above 80%. For the robustness determination in urine, the accuracy of four different sources of urine at the mid control level (1 microg/mL) ranged from 1.6 to 19% error. The % relative standard deviation of the different urine sources ranged from 3.1 to 11%. Urine samples from nine methamphetamine-positive cases investigated by the Office of the Chief Medical Examiner of West Virginia were included in the study. 1-Phenylpropene was found in two methamphetamine-positive cases (0.25 and 0.44 microg/mL).

  9. Liquid chromatographic and spectrophotometric methods for the determination of erythromycin stearate and trimethoprim in tablets

    Directory of Open Access Journals (Sweden)

    Sonia T. Hassib

    2011-12-01

    Full Text Available Simple, accurate and precise reversed-phase liquid chromatographic (LC and spectrophotometric methods have been developed and validated for the determination of erythromycin stearate (ERS and trimethoprim (TMP in mixture. In LC method, chromatographic separation was achieved on a Symmetry® Waters C18 column (150 × 4.6 mm, 5 μm based on isocratic elution using a mobile phase consisting of potassium dihydrogen phosphate buffer pH (9:acetonitrile:water (25:100:50, v/v/v at a flow rate of 1.6 ml min−1 with UV detection at 210 nm for ERS and 280 nm for TMP. Besides, two spectrophotometric methods were applied after reaction with perchloric acid (12 M which gives a colored product with ERS. Then, the spectral interference between the colored product of ERS and TMP was resolved by either ratio spectra derivative spectrophotometry in the first spectrophotometric method or chemometric techniques, namely classical least-squares (CLS, principal component regression (PCR and partial least-squares regression (PLS in the second spectrophotometric method. The results were statistically compared using one-way analysis of variance (ANOVA. The methods developed were satisfactorily applied to the analysis of the pharmaceutical preparation containing the two drugs and proved to be specific and accurate for the quality control of the cited drugs in pharmaceutical dosage forms.

  10. Comparison of the ion exclusion chromatographic method with the Monier-Williams method for determination of total sulfite in foods.

    Science.gov (United States)

    Kim, H J

    1989-01-01

    Experimental data comparing the alkali extraction/ion exclusion chromatographic method with the Monier-Williams method for determination of total sulfite are presented in (a) enzymatic and nonenzymatic browning systems, (b) vegetables containing naturally occurring sulfite, and (c) a carbohydrate-type food additive, erythorbic acid. Excellent agreement, with a linear correlation coefficient of 0.99, was observed in fresh potato samples homogenized with sulfite and allowed to react for different time intervals (enzymatic browning system). A good overall correlation was observed in dehydrated, sulfited apple samples heated for different times (nonenzymatic browning system); however, as heating time increased, higher results were obtained by the Monier-Williams method than by the alkali extraction/ion exclusion chromatographic method. The results of determining sulfite in the alkali trapping solution following acid distillation or acid treatment without heat suggested that this deviation was due to a fraction of sulfite bound to the browning reaction products in such a way that it was released by acid distillation but not by alkali extraction or acid treatment without heat. Similar behavior was demonstrated in cabbage with naturally occurring sulfite, which was released by acid distillation but not by alkali extraction or acid treatment without heat. The ion exclusion chromatographic method could overcome interference by the volatile caramelization reaction products in the Monier-Williams determination of erythorbic acid.

  11. Nuclear Magnetic Resonance and Headspace Solid-Phase Microextraction Gas Chromatography as Complementary Methods for the Analysis of Beer Samples

    Directory of Open Access Journals (Sweden)

    Sarah R. Johnson

    2017-04-01

    Full Text Available Chemical analysis of the organic components in beer has applications to quality control, authenticity and improvements to the flavor characteristics and brewing process. This study aims to show the complementary nature of two instrumental techniques which, in combination, can identify and quantify a number of organic components in a beer sample. Nuclear Magnetic Resonance (NMR was used to provide concentrations of 26 different organic compounds including alcohols, organic acids, carbohydrates, and amino acids. Calorie content was also estimated for the samples. NMR data for ethanol concentrations were validated by comparison to a Fourier Transform Infrared Spectrometry (FTIR method. Headspace Solid-Phase Microextraction (SPME Gas Chromatography Mass Spectrometry (GCMS was used to identify a range of volatile compounds such as alcohols, esters and hop-derived aroma compounds. A simple and inexpensive conversion of a Gas Chromatography Flame Ionization Detector (GC FID instrument to allow the use of Solid-Phase Microextraction was found to be useful for the quantification of volatile esters.

  12. High-Performance Liquid Chromatographic and High-Performance Thin-Layer Chromatographic Method for Quantitative Estimation of Dolutegravir Sodium in Bulk Drug and Pharmaceutical Dosage Form

    OpenAIRE

    Bhavar, Girija B.; Sanjay S. Pekamwar; Aher, Kiran B.; Thorat, Ravindra S.; Chaudhari, Sanjay R.

    2015-01-01

    Simple, sensitive, precise, and specific high-performance liquid chromategraphic (HPLC) and high-performance thin-layer chromatographic (HPTLC) methods for the determination of dolutegravir sodium in bulk drug and pharmaceutical dosage form were developed and validated. In the HPLC method, analysis of the drug was carried out on the ODS C18 column (150 ? 4.6 mm, 5 ?m particle size) using a mixture of acetonitrile: water (pH 7.5) in the ratio of 80:20 v/v as the mobile phase at the flow rate 1...

  13. Headspace profiling of cocaine samples for intelligence purposes.

    Science.gov (United States)

    Dujourdy, Laurence; Besacier, Fabrice

    2008-08-06

    A method for determination of residual solvents in illicit hydrochloride cocaine samples using static headspace-gas chromatography (HS-GC) associated with a storage computerized procedure is described for the profiling and comparison of seizures. The system involves a gas chromatographic separation of 18 occluded solvents followed by fully automatic data analysis and transfer to a PHP/MySQL database. First, a fractional factorial design was used to evaluate the main effects of some critical method parameters (salt choice, vial agitation intensity, oven temperature, pressurization and loop equilibration) on the results with a minimum of experiments. The method was then validated for tactical intelligence purposes (batch comparison) via several studies: selection of solvents and mathematical comparison tool, reproducibility and "cutting" influence studies. The decision threshold to determine the similarity of two samples was set and false positives and negatives evaluated. Finally, application of the method to distinguish geographical origins is discussed.

  14. Development and validation of a reversed phase liquid chromatographic method for analysis of griseofulvin and impurities.

    Science.gov (United States)

    Kahsay, Getu; Adegoke, Aremu Olajire; Van Schepdael, Ann; Adams, Erwin

    2013-06-01

    A simple and robust reversed phase liquid chromatographic method was developed and validated for the quantitative determination of griseofulvin (GF) and its impurities in drug substances and drug products (tablets). Chromatographic separation was achieved on a Discovery C18 (250mm×4.6mm, 5μm) column kept at 30°C. The mobile phase consisted of a gradient mixture of mobile phase A (water-0.1% formic acid pH 4.5, 80:20, v/v) and B (ACN-water-0.1% formic acid pH 4.5, 65:15:20, v/v/v) pumped at a flow rate of 1.0mL/min. UV detection was performed at 290nm. The method was validated for its robustness, sensitivity, precision, accuracy and linearity based on ICH guidelines. The robustness study was performed by means of an experimental design and multivariate analysis. Satisfactory results were obtained from the validation studies. The use of volatile mobile phases allowed for the identification of three main impurities present above the identification threshold using mass spectrometry (MS). The developed LC method has been applied for the assay and impurity determination of GF drug substances and tablets. The method could be very useful for the quality control of GF and its impurities in bulk and formulated dosage forms. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Volatile profile of yellow passion fruit juice by static headspace and solid phase microextraction techniques

    Directory of Open Access Journals (Sweden)

    Gilberto Costa Braga

    2015-02-01

    Full Text Available The profile of volatile compounds of yellow passion fruit juice was analyzed by solid phase microextraction headspace (HS-SPME and optimized static headspace (S-HS extraction techniques. Time, temperature, NaCl concentration and sample volume headspace equilibrium parameters was adjusted to the S-HS technique. The gaseous phase in the headspace of samples was collected and injected into a gas chromatograph coupled to a mass spectrometer. In the HS-SPME technique was identified 44 volatile compounds from the yellow passion fruit juice, but with S-HS only 30 compounds were identified. Volatile esters were majority in both techniques, being identified ethyl butanoate, ethyl hexanoate, (3z-3-hexenyl acetate, hexyl acetate, hexyl butanoate and hexyl hexanoate. Aldehydes and ketones were not identified in S-HS, but were in HS-SPME. β-Pinene, p-cymene, limonene, (Z-β-ocimene, (E-β-ocimene, γ-terpinene, α-terpinolene and (E -4,8-dimethyl-1, 3,7 - nonatriene terpenes were identified in both techniques. This study showed that the S-HS optimized extraction technique was effective to recovery high concentrations of the major volatile characteristics compounds in the passion fruit, such as ethyl butanoate and ethyl hexanoate, which can be advantageous due to the simplicity of the method.

  16. Liquid Chromatographic Method for the Determination of Caffeoylquinic Acid Derivates in Hieracium pilosella L.

    Science.gov (United States)

    Borisova-Jan, Larisa; Fransson, Dick; Claeson, Per; Burman, Robert

    2017-11-01

    Hieracium pilosella L. is a medicinal plant encountered in Europe in traditional herbal medicinal products. Caffeoylquinic (ortho-dihydroxycinnamic) acid derivatives are characteristic constituents used as analytical markers in the quality control of the herbal material. Until now, the caffeoylquinic acid derivatives have been assayed using a colorimetric method according to the French Pharmacopoeia. To develop an HPLC-method for quantification of caffeoylquinic acid derivatives in H. pilosella. Samples were prepared by methanol extraction of H. pilosella, dried herb. An HPLC method suitable for analysis was developed and validated. The content of caffeoylquinic acid derivatives was determined and expressed as chlorogenic acid. Individual substances in the samples were identified by analyses of UV-MS/MS spectra and by comparisons with spectra and chromatographic retention times of authentic reference substances. Validation showed that the chromatographic method has good selectivity with no interfering peaks. Sensitivity, linearity, repeatability and accuracy were shown to be adequate. In analyses of several batches of H. pilosella, contents of caffeoylquinic acids ranging from 0.7 to 1.9% were found. Compared to the colorimetric method, this newly developed HPLC method is more specific and results in detection of nominally lower amounts of caffeoylquinic acid derivatives. A new acceptance limit of 1.0% instead of 2.5% caffeoylquinic acid, expressed as chlorogenic acid, for H. pilosella, is proposed when using this HPLC-method. A newly developed HPLC method is shown to be appropriate for quantitative determination of caffeoylquinic acid derivatives in H. pilosella. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  17. Headspace solid phase microextraction (HSSPME) for the determination of volatile and semivolatile pollutants in soils

    Energy Technology Data Exchange (ETDEWEB)

    Llompart, Maria [Departamento de Quimica Analitica Nutricion y Bromatologia, Facultad de Quimica, Universidad de Santiago de Compostela, E-15706 Santiago de Compostela (Spain); Li, Ken; Fingas, Merv [Emergencies Science Division, Environment Canada, Environmental Technology Centre, 3439 River Road, Ottawa, ON (Canada)

    1999-02-08

    We have investigated the use of headspace solid phase microextraction (HSSPME) as a sample concentration and preparation technique for the analysis of volatile and semivolatile pollutants in soil samples. Soil samples were suspended in solvent and the SPME fibre suspended in the headspace above the slurry. Finally, the fibre was desorbed in the Gas Chromatograph (GC) injection port and the analysis of the samples was carried out. Since the transfer of contaminants from the soil to the SPME fibre involves four separate phases (soil-solvent-headspace and fibre coating), parameters affecting the distribution of the analytes were investigated. Using a well-aged artificially spiked garden soil, different solvents (both organic and aqueous) were used to enhance the release of the contaminants from the solid matrix to the headspace. It was found that simple addition of water is adequate for the purpose of analysing the target volatile organic chemicals (VOCs) in soil. The addition of 1 ml of water to 1 g of soil yielded maximum response. Without water addition, the target VOCs were almost not released from the matrix and a poor response was observed. The effect of headspace volume on response as well as the addition of salt were also investigated. Comparison studies between conventional static headspace (HS) at high temperature (95C) and the new technology HSSPME at room temperature (=20C) were performed. The results obtained with both techniques were in good agreement. HSSPME precision and linearity were found to be better than automated headspace method and HSSPME also produced a significant enhancement in response. The detection and quantification limits for the target VOCs in soils were in the sub-ng g{sup -1} level. Finally, we tried to extend the applicability of the method to the analysis of semivolatiles. For these studies, two natural soils contaminated with diesel fuel and wood preservative, as well as a standard urban dust contaminated with polyaromatic

  18. Analysis of aroma compounds of Roselle by Dynamic Headspace Sampling using different preparation methods

    DEFF Research Database (Denmark)

    Juhari, Nurul Hanisah Binti; Varming, Camilla; Petersen, Mikael Agerlin

    2015-01-01

    The influence of different methods of sample preparation on the aroma profiles of dried Roselle (Hibiscus sabdariffa) was studied. Least amounts of aroma compounds were recovered by analysis of whole dry calyxes (WD) followed by ground dry (GD), blended together with water (BTW), and ground...... and then mixed with water (GMW). The highest number of aroma compounds was found in Roselle treated in water bath (2hr/40°C) (GMWKB). GMW was chosen as the preparation method because it was shown to be an efficient extraction method without the possibility of excessive chemical changes of the sample....

  19. Current Applications of Chromatographic Methods in the Study of Human Body Fluids for Diagnosing Disorders.

    Science.gov (United States)

    Jóźwik, Jagoda; Kałużna-Czaplińska, Joanna

    2016-01-01

    Currently, analysis of various human body fluids is one of the most essential and promising approaches to enable the discovery of biomarkers or pathophysiological mechanisms for disorders and diseases. Analysis of these fluids is challenging due to their complex composition and unique characteristics. Development of new analytical methods in this field has made it possible to analyze body fluids with higher selectivity, sensitivity, and precision. The composition and concentration of analytes in body fluids are most often determined by chromatography-based techniques. There is no doubt that proper use of knowledge that comes from a better understanding of the role of body fluids requires the cooperation of scientists of diverse specializations, including analytical chemists, biologists, and physicians. This article summarizes current knowledge about the application of different chromatographic methods in analyses of a wide range of compounds in human body fluids in order to diagnose certain diseases and disorders.

  20. Low-temperature headspace-trap gas chromatography with mass spectrometry for the determination of trace volatile compounds from the fruit of Lycium barbarum L.

    Science.gov (United States)

    Chen, Fangjiao; Su, Yue; Zhang, Fang; Guo, Yinlong

    2015-02-01

    The total saccharides content of Lycium barbarum L. is very high, and a high temperature would result in saccharide decomposition and the emergence of a large amount of water. Moreover, the volatile compounds from the fruit of L. barbarum L. are rather low in concentration. Hence, it is difficult for a conventional headspace method to study the volatile compounds from the fruit of L. barbarum L. Since headspace-trap gas chromatography with mass spectrometry is an excellent method for trace analysis, a headspace-trap gas chromatography with mass spectrometry method based on low-temperature (30°C) enrichment and multiple headspace extraction was developed to explore the volatile compounds from the fruit of L. barbarum L. The headspace of the sample was extracted in 17 cycles at 30°C. Each time, the compounds extracted were concentrated in the trap (Tenax TA and Tenax GR, 1:1). Finally, all the volatile compounds were delivered into the gas chromatograph after thermal desorption. With the method described above, a total of 57 compounds were identified. The identification was completed by mass spectral search, retention index, and accurate mass measurement. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Chromatographic Fingerprints Combined with Chemometric Methods Reveal the Chemical Features of Authentic Radix Polygalae.

    Science.gov (United States)

    Xin, Zhongquan; Ren, Dabing; Zhang, Xiaojuan; Yi, Zhibiao; Yi, Lunzhao

    2017-01-01

    GC-MS fingerprints of Radix Polygalae (RP) were measured for deliberately collected samples. A total of 88 volatile components were identified and quantified by subwindow factor analysis, heuristic evolving latent projection, and retention index. Next, an efficient discrimination model based on partial least-squares (PLS) discriminant analysis (DA) was developed to distinguish the superior RP samples from the inferior ones, and the reliability and predictive ability of the model was evaluated by cross-validation and permutation tests. Furthermore, four components (1-octanol, shyobunone, isobornyl acetate, and α-asarone) were screened by coefficient β of PLS-DA. They represented the important chemical features of authentic RP and could be applied to the accurate discrimination and QC of RP in the future. Our results suggest that chromatographic fingerprints coupled with chemometric methods provide an effective and convenient strategy for QC of RP and are helpful for revealing the chemical features of a complex analytical sample.

  2. Liquid chromatographic method for the determination of enantiomeric composition of amphetamine and methamphetamine in hair samples.

    Science.gov (United States)

    Phinney, Karen W; Sander, Lane C

    2004-01-01

    Interest in hair analysis as an alternative or complementary approach to urinalysis for drug abuse detection has grown in recent years. Hair analysis can be particularly advantageous for drugs such as amphetamine and methamphetamine that are rapidly excreted. Confirmation of abuse of these stimulants is complicated by the fact that some forms are found in legitimate medications. Examination of the enantiomeric composition of amphetamine and methamphetamine in hair samples can provide valuable assistance in interpreting drug testing results. In this work, we developed a liquid chromatographic method for the separation of amphetamine and methamphetamine enantiomers isolated from human hair samples. The drug enantiomers were separated on a chiral stationary phase after derivatization with an achiral fluorescent agent. The methodology was evaluated with a Standard Reference Material that contained several drugs of abuse including amphetamine and methamphetamine.

  3. Development of a New Calibration Method for an Ambient Ion Monitor Ion Chromatograph (AIM-IC)

    Science.gov (United States)

    Markovic, M.; Vandenboer, T.; Murphy, J. G.

    2009-05-01

    Fine atmospheric aerosols play an important role in the atmosphere as they alter the radiative balance of the Earth through direct and indirect climate effects, reduce visibility, participate in acid rain formation and affect human health. The motivation for chemically and temporally resolved measurements of fine aerosol composition has lead to the development of the Ambient Ion Monitor Ion Chromatograph (AIM-IC) system by Dionex/URG. This instrument is capable of simultaneously monitoring fine aerosols (acids and amines. Standard calibration of the AIM-IC is carried out by injecting a series of mixed standards directly onto the ion chromatographs, bypassing the sampling component of the instrument. This results in calculated detection limits on the order of 10-200 pptv for gases and 10-500 of ng/m3 for individual particle constituents when collecting at 3 L/min for 55 minutes. In this work, we present a new method for the calibration of the AIM-IC for both gas and particle collection that enables us to evaluate the entire system from size-selection to detection. This external calibration method is assessed for the gases HNO3(g), SO2(g), and NH3(g), and for particles containing (NH4)2SO4, NH4NO3, and Na2SO4. Quantitative collection of SO2 is found to require careful optimization of the H2O2 concentration of the denuder liquid, while the replacement of a cyclone with an impactor improves the sampling efficiency of NH3 and HNO3.

  4. Efficient determination of average valence of manganese in manganese oxides by reaction headspace gas chromatography.

    Science.gov (United States)

    Xie, Wei-Qi; Gong, Yi-Xian; Yu, Kong-Xian

    2017-08-18

    This work investigates a new reaction headspace gas chromatographic (HS-GC) technique for efficient quantifying average valence of manganese (Mn) in manganese oxides. This method is on the basis of the oxidation reaction between manganese oxides and sodium oxalate under the acidic condition. The carbon dioxide (CO2) formed from the oxidation reaction can be quantitatively analyzed by headspace gas chromatography. The data showed that the reaction in the closed headspace vial can be completed in 20min at 80°C. The relative standard deviation of this reaction HS-GC method in the precision testing was within 1.08%, the relative differences between the new method and the reference method (titration method) were no more than 5.71%. The new HS-GC method is automated, efficient, and can be a reliable tool for the quantitative analysis of average valence of manganese in the manganese oxide related research and applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Development and comparison of chromatographic methods for the analysis of long chain diols and alkenones in biological materials and sediment

    NARCIS (Netherlands)

    de Bar, M.W.; Hopmans, E.C.; Verweij, M.; Dorhout, D.J.C.; Sinninghe Damsté, J.S.; Schouten, S.

    2017-01-01

    We have compared and assessed the suitability of several chromatographic methods for the analysis of long chain alkenones and long chain diols and the associated paleotemperature proxies (UK’37 and LDI). We evaluated the traditional methods for the analysis of the UK’37 and the LDI, gas

  6. Magnetic ionic liquids as extraction solvents in vacuum headspace single-drop microextraction.

    Science.gov (United States)

    Trujillo-Rodríguez, María J; Pino, Verónica; Anderson, Jared L

    2017-09-01

    A vacuum headspace single-drop microextraction method based on the use of magnetic ionic liquids (vacuum MIL-HS-SDME) for the determination of short chain free fatty acids is described for the first time. The basis of the method involves the use of a rod magnet to aid in maintaining a small microdroplet of magnetic ionic liquid (MIL) during headspace single-drop microextraction (HS-SDME). The application favors reduced pressure conditions inside the sampling vial while maintaining the MIL droplet in the headspace. After extraction, the MIL microdroplet containing extracted FFAs is transferred to a headspace vial where static headspace desorption is performed, followed by gas chromatographic-mass spectrometry (GC-MS) analysis. A number of MILs were studied and the trihexyl(tetradecyl)phosphonium tris(hexafluoroacetylaceto)manganate(II) MIL was found to be the most suitable for the proposed method. A comparison with atmospheric pressure MIL-HS-SDME revealed that analytes reached equilibrium faster when reduced pressure conditions were applied and that an enhancement in the extraction efficiency of analytes under these vacuum conditions was observed at any extraction time. Under optimum conditions, the method requires only 20µL of MIL placed at the end of a rod magnet and the evacuation of air using a modified extraction vial and a vacuum pump. Afterwards, 10mL of sample containing 30% (w/v) of NaCl is injected in the vial and the vacuum MIL-HS-SDME is performed at 45°C and 600rpm for 60min. The MIL microdroplet can easily be transferred to a 4.2mL modified headspace vial for the headspace desorption and GC-MS analysis. The entire method is characterized by wide linearity ranges, low limits of detection for analytes (down to 14.5µgL-1), good reproducibility (with relative standard deviation lower than 13%), and relative recoveries ranging from 79.5% to 111%. The proposed vacuum MIL-HS-SDME was applied towards the analysis of two different milk samples with the

  7. Development of syringe pump assisted headspace sampler.

    Science.gov (United States)

    Go, Un Jeong; Eom, In-Yong

    2014-09-26

    This report describes a new platform for headspace sampling technique, i.e. a syringe pump assisted headspace sampler (SPHS). The stand type pump's syringe itself was used as a sealed sample vial and a needle trap device (NTD) was adopted as a miniaturized sorbent tube. The NTD was directly used to inject trapped VOCs into a gas chromatograph. The proposed sampler was designed to take a whole headspace volume instead of a portion of it so as to enhance easily the extraction efficiency. The performance of the SPHS-NTD system was evaluated and compared with the solid-phase microextraction (SPME) with a static headspace (HS) sampling technique. Calibration curves were obtained for aqueous TEX (toluene, ethylbenzene, and o-xylene) solutions in the concentration range of ∼0.1-45 ng/mL. The calculated limit of detections (LOD, S/N=3) for TEX were 0.13 ng/mL or less. This SPHS-NTD was successfully applied to analyze aqueous TEX in river water samples and showed highly good recovery ranged from 97.2% to 105.8% for all tested VOCs. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Alternative non-chromatographic method for alcohols determination in Clostridium acetobutylicum fermentations.

    Science.gov (United States)

    Noriega-Medrano, Laura J; Vega-Estrada, Jesús; Ortega-López, Jaime; Ruiz-Medrano, Roberto; Cristiani-Urbina, Eliseo; Montes-Horcasitas, Maria Del Carmen

    2016-07-01

    An economic, simple, quantitative, and non-chromatographic method for the determination of alcohols using microdiffusion principle has been adapted and validated for acetone-butanol-ethanol (ABE) fermentation samples. This method, based on alcohols oxidation using potassium dichromate in acid medium, and detection by spectrophotometry, was evaluated varying, both, temperature (35°C, 45°C, and 55°C) and reaction time (0 to 125min). With a sample analysis time of 90min at 45°C, a limit of detection (LOD), and a limit of quantification (LOQ) of 0.10, and 0.40g/L, respectively. The proposed method has been successfully applied to determine butanol and ethanol concentrations in ABE fermentation samples with the advantage that multiple samples can be analyzed simultaneously. The measurements obtained with the proposed method were in good agreement with those obtained with the Gas Chromatography Method (GCM). This proposed method is useful for routine analysis of alcohols and screening samples in laboratories and industries. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Ion Chromatographic Method with Post-Column Fuchsin Reaction for Measurement of Bromate in Chlorinated Water

    Directory of Open Access Journals (Sweden)

    Homer C. Genuino

    2009-06-01

    Full Text Available An ion chromatographic method that employs a post-column reaction with fuchsin and spectrophotometric detection was optimized for measuring bromate (BrO3- in water. BrO3- is converted to Br2 by sodium metabisulfite and then reacted with acidic fuchsin to form a red-colored product that strongly absorbs at 530 nm. The reaction of BrO3- and fuchsin reagent is optimum at pH 3.5 and 65 oC. The method has a limit of quantitation of 4.5 µg L-1 and is linear up to 150 µg L-1 BrO3-. Recoveries from spiked samples were high ranging from 95 to 102 % using external standard calibration and 87 to 103 % using standard addition method. Intra-batch and inter-batch reproducibility studies of the method resulted to RSD values ranging from 0.62 to 2.01 % and percent relative error of 0.12 to 2.94 % for BrO3- concentrations of 10 µg L-1 and 50 µg L-1. This method is free of interferences from common inorganic anions at levels typically found in chlorinated tap drinking water without preconcentration. The optimized method can be applied to trace analysis of bromate in chlorinated tap drinking water samples.

  10. Improvement of a headspace solid phase microextraction-gas chromatography/mass spectrometry method for the analysis of wheat bread volatile compounds.

    Science.gov (United States)

    Raffo, Antonio; Carcea, Marina; Castagna, Claudia; Magrì, Andrea

    2015-08-07

    An improved method based on headspace solid phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME/GC-MS) was proposed for the semi-quantitative determination of wheat bread volatile compounds isolated from both whole slice and crust samples. A DVB/CAR/PDMS fibre was used to extract volatiles from the headspace of a bread powdered sample dispersed in a sodium chloride (20%) aqueous solution and kept for 60min at 50°C under controlled stirring. Thirty-nine out of all the extracted volatiles were fully identified, whereas for 95 other volatiles a tentative identification was proposed, to give a complete as possible profile of wheat bread volatile compounds. The use of an array of ten structurally and physicochemically similar internal standards allowed to markedly improve method precision with respect to previous HS-SPME/GC-MS methods for bread volatiles. Good linearity of the method was verified for a selection of volatiles from several chemical groups by calibration with matrix-matched extraction solutions. This simple, rapid, precise and sensitive method could represent a valuable tool to obtain semi-quantitative information when investigating the influence of technological factors on volatiles formation in wheat bread and other bakery products. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Simple high-performance liquid chromatographic method to analyse megazol in human and rat plasma.

    Science.gov (United States)

    Enanga, B; Labat, C; Boudra, H; Chauvière, G; Keita, M; Bouteille, B; Dumas, M; Houin, G

    1997-08-29

    A simple and sensitive high-performance liquid chromatographic method has been developed to measure megazol in human plasma. The method was optimized and validated according to the Washington Concensus Conference on the Validation of Analytical Methods (V.P. Shah et al., Eur. J. Drug Metab. Pharmacokinet., 15 (1991) 249). The criteria of complete validation were specificity, linearity, precision, analytical recovery, dilution and stability. It involved extraction of the plasma with dichloromethane, followed by reversed-phase high-performance liquid chromatography using a Kromasil C8 column and UV detection at 360 nm. The retention times of the internal standard (tinidazol) and megazol were 6.10 and 9.60 min, respectively. The standard curve was linear from 2 ng ml-1 (limit of quantification) to 2000 ng ml-1. The coefficients of variation for all the criteria of validation were less than 6%; 85 to 92% extraction efficiencies were obtained. Megazol was stable during the storage period (one month at -20 degrees C) in plasma and for two months at 25 degrees C in standard solution. The method was tested by measuring the plasma concentration following oral administration to rat and was shown to be suitable for pharmacokinetic studies.

  12. A purge-and-trap capillary column gas chromatographic method for the measurement of halocarbons in water and air

    Energy Technology Data Exchange (ETDEWEB)

    Happell, J.D.; Wallace, D.W.R.; Wills, K.D.; Wilke, R.J.; Neill, C.C.

    1996-06-01

    This report describes an automated, accurate, precise and sensitive capillary column purge- and -trap method capable of quantifying CFC-12, CFC-11, CFC-113, CH{sub 3}CCL{sub 3}, and CCL{sub 4} during a single chromatographic analysis in either water or gas phase samples.

  13. Liquid chromatographic method for determination of water in soils and the optimization of anion separations by capillary zone electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Benz, Nancy [Iowa State Univ., Ames, IA (United States)

    1994-01-01

    A liquid chromatographic method for the determination of water in soil or clay samples is presented. In a separate study, the optimization of electrophoretic separation of alkylated phenolate ions was optimized by varying the pH and acetonitrile concentration of the buffer solutions.

  14. Validation of a liquid chromatographic method for the pharmaceutical quality control of products containing elacridar

    Directory of Open Access Journals (Sweden)

    Emilia Sawicki

    2016-08-01

    Full Text Available Many anticancer drugs have an impaired bioavailability and poor brain penetration because they are substrates to drug efflux pumps such as P-glycoprotein and Breast Cancer Resistance Protein. Elacridar is a strong inhibitor of these two drug efflux pumps and therefore has great potential to improve oral absorption and brain penetration of many anticancer drugs. Currently, a clinical formulation of elacridar is unavailable and therefore the pharmaceutical development of a drug product is highly warranted. This also necessitates the availability of an analytical method for its quality control. A reverse-phase high-performance liquid chromatographic method with ultraviolet detection was developed for the pharmaceutical quality control of products containing elacridar as the active pharmaceutical ingredient. The analytical method was validated for linearity, accuracy, precision, selectivity, carry-over, stability of stock and reference solutions, stability of the final extract, stability-indicating capability and impurity testing. We found that elacridar is unstable in aqueous solutions that are exposed to light because a hydroxylation product of elacridar is formed. Therefore, sample solutions with elacridar must be protected from light.

  15. Comparison of Aurantii Fructus Immaturus and Aurantii Fructus based on multiple chromatographic analysis and chemometrics methods.

    Science.gov (United States)

    Li, Pei; Zeng, Su-Ling; Duan, Li; Ma, Xiao-Dong; Dou, Li-Li; Wang, Lan-Jin; Li, Ping; Bi, Zhi-Ming; Liu, E-Hu

    2016-10-21

    To get a better understanding of the bioactive constituents in Aurantii Fructus Immaturus (AFI) and Aurantii Fructus (AF), in the present study, a comprehensive strategy integrating multiple chromatographic analysis and chemometrics methods was firstly proposed. Based on segmental monitoring, a high-performance liquid chromatography (HPLC)-variable wavelength detection method was established for simultaneous quantification of ten major flavonoids, and the quantitative data were further analyzed by hierarchical cluster analysis (HCA) and principal component analysis (PCA). A strong cation exchange-high performance liquid chromatography (SCX-HPLC) method combined with t-test and one-way analysis of variance (ANOVA) was developed to determine synephrine, the major alkaloid in AFI and AF. The essential oils were analyzed by gas chromatography-mass spectrometry (GC-MS) and further processed by partial least squares discrimination analysis (PLS-DA). The results indicated that the contents of ten flavonoids and synephrine in AFI were significantly higher than those in AF, and significant difference existed in samples from different geographical origins. Also, 9 differential volatile constituents detected could be used as chemical markers for discrimination of AFI and AF. Collectively, the proposed comprehensive analysis might be a well-acceptable strategy to evaluate the quality of traditional citrus herbs. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Stability-indicating high-performance liquid chromatographic assay method and photostability of carprofen.

    Science.gov (United States)

    Wu, A B; Chen, C Y; Chu, S D; Tsai, Y C; Chen, F A

    2001-01-01

    A rapid, sensitive, and accurate stability-indicating high-performance liquid chromatographic assay method for determining the degradation of carprofen (CPF) is developed and validated under acidic, basic, or photo-irradiated conditions. The analysis is monitored with a Cosmosil 5C18-AR column using a mobile phase of CH3CN-H2O-AcOH (50:49:1, v/v/v) at 260 nm. The developed method satisfies the system suitability criteria, peak integrity, and resolution among the parent drug and its degradation products. The results indicate that the established assay method shows good selectivity and specificity suitable for stability measurements of CPF. CPF is found to be more sensitive to exposure to light and in acidic conditions, but it is stable in a basic medium. The kinetic study of the photodegradation of CPF follows an apparent first-order reaction in a variety of solvents. The solvent effects on the rates of degradation are in the decreasing order of chloroform > dichloromethane > methanol > ethanol > 2-propanol, which is irrelevant to the dielectric constant epsilon. However, the hydrogen-donating ability of the solvents is essential to the photochemical decomposition of CPF. A plot of log k versus the Kirkwood function exhibits a linear relationship in aqueous ethanolic solutions, which implies that degradation proceeds via an ionic mechanism.

  17. Determination of the content of alkyl ketene dimer in its latex by an ionic-liquid assisted headspace gas chromatography.

    Science.gov (United States)

    Yan, Ning; Wan, Xiao-Fang; Chai, Xin-Sheng; Chen, Run-Quan; Chen, Chun-Xia

    2017-12-29

    This paper reports on an ionic-liquid assisted headspace gas chromatographic (HS-GC) for the determination of the content of alkyl ketene dimer (AKD) in its latex samples, in which the GC system was equipped with a thermal conductivity detector (TCD). The method was based on the AKD hydrolysis conducted in 1-butyl-3-methylimidazolium chloride (ionic-liquid) added medium at 100°C for 10min in a closed headspace sample vial, and the measured CO 2 (the resulting product of the hydrolysis) by HS-GC. The results showed that the present method has a good measurement precision (RSD latex sample in mill applications. The study also showed that the content of AKD in the tested commercial latex samples were in the range of 3.5-12%. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Development and Validation of Liquid Chromatographic Method for Estimation of Naringin in Nanoformulation

    Directory of Open Access Journals (Sweden)

    Kranti P. Musmade

    2014-01-01

    Full Text Available A simple, precise, accurate, rapid, and sensitive reverse phase high performance liquid chromatography (RP-HPLC method with UV detection has been developed and validated for quantification of naringin (NAR in novel pharmaceutical formulation. NAR is a polyphenolic flavonoid present in most of the citrus plants having variety of pharmacological activities. Method optimization was carried out by considering the various parameters such as effect of pH and column. The analyte was separated by employing a C18 (250.0 × 4.6 mm, 5 μm column at ambient temperature in isocratic conditions using phosphate buffer pH 3.5: acetonitrile (75 : 25% v/v as mobile phase pumped at a flow rate of 1.0 mL/min. UV detection was carried out at 282 nm. The developed method was validated according to ICH guidelines Q2(R1. The method was found to be precise and accurate on statistical evaluation with a linearity range of 0.1 to 20.0 μg/mL for NAR. The intra- and interday precision studies showed good reproducibility with coefficients of variation (CV less than 1.0%. The mean recovery of NAR was found to be 99.33 ± 0.16%. The proposed method was found to be highly accurate, sensitive, and robust. The proposed liquid chromatographic method was successfully employed for the routine analysis of said compound in developed novel nanopharmaceuticals. The presence of excipients did not show any interference on the determination of NAR, indicating method specificity.

  19. Multiresidue liquid chromatographic method for determining residues of mono- and dibasic penicillins in bovine muscle tissues.

    Science.gov (United States)

    Boison, J O; Keng, L J

    1998-01-01

    A liquid chromatographic method with UV detection at 325 nm was developed for simultaneous determination of amoxicillin, ampicillin, penicillin G, and cloxacillin residues in bovine muscle tissue as their mercaptide derivatives. The penicillins are extracted from bovine tissues with 0.1 M phosphate buffer (pH 8.5), cleaned up on a t-C18 Sep-Pak cartridge, and eluted with 2 mL acetonitrile. After the acetonitrile in the eluate is evaporated to dryness, the residue is dissolved in 200 microL (40 + 60, v/v) acetonitrile-phosphate buffer (pH 6.5) and derivatized with acetic anhydride and mercuric chloride in the presence of 1,2,4-triazole at 65 degrees C for 30 min. Gradient analysis on a Spherisorb 5 microns ODS(2) (octadecyl silane) analytical column using a binary mobile phase consisting of acetonitrile and 0.10 M phosphate buffer (pH 6.5) in the presence of 0.0157 M sodium thiosulfate at 1 mL/min permits determination of each intact penicillin in bovine muscle tissue at > or = 10 ppb with recoveries > or = 72%. This laboratory method provides detection sensitivities equivalent to those of rapid tests used for screening beta-lactam drug residues in bovine tissue samples for regulatory enforcement.

  20. A chromatographic method for the production of a human immunoglobulin G solution for intravenous use

    Directory of Open Access Journals (Sweden)

    K. Tanaka

    1998-11-01

    Full Text Available Immunoglobulin G (IgG of excellent quality for intravenous use was obtained from the cryosupernatant of human plasma by a chromatographic method based on a mixture of ion-exchange, DEAE-Sepharose FF and arginine Sepharose 4B affinity chromatography and a final purification step by Sephacryl S-300 HR gel filtration. The yield of 10 experimental batches produced was 3.5 g IgG per liter of plasma. A solvent/detergent combination of 1% Tri (n-butyl phosphate and 1% Triton X-100 was used to inactivate lipid-coated viruses. Analysis of the final product (5% liquid IgG based on the mean for 10 batches showed 94% monomers, 5.5% dimers and 0.5% polymers and aggregates. Anticomplementary activity was 0.3 CH50/mg IgG and prekallikrein activator levels were less than 5 IU/ml. Stability at 37ºC for 30 days in the liquid state was satisfactory. IgG was stored in flasks (2.5 g/flask at 4 to 8ºC. All the characteristics of the product were consistent with the requirements of the 1997 Pharmacopée Européenne.

  1. Determination of competitive adsorption isotherm of enantiomers on preparative chromatographic columns using inverse method.

    Science.gov (United States)

    Xu, Jin; Zhu, Lei; Xu, Guoqian; Yu, Weifang; Ray, Ajar K

    2013-01-18

    Precise determination of competitive adsorption isotherm is of great importance for model-based optimization and scale-up of chromatographic separation processes, particularly for the simulated moving bed (SMB) systems due to its intrinsic complexity. In this study, five parameters of a bi-Langmuir model for adsorption of ketoprofen enantiomers on a preparative Chiralpak AD column at 25°C were determined by the application of inverse method (IM). Transport-dispersive (TD) model parameters, axial dispersion and mass transfer coefficients were independently estimated first by tuning a series of linear pulse experiments. Competitive adsorption isotherm model parameters were then determined independently by fitting the experimental data. A new numerical scheme that couples non-dominated sorting genetic algorithm (NSGA) and Levenberg-Marquardt algorithm (LMA) was proposed for the data fitting. NSGA was capable of rapidly locating the optimal solution in the parametric space while LGA allowed speedy convergence given a good initial guess. Independently measured band profiles and simulated moving bed (SMB) experiments were later used to validate the model parameters. The experimental results were in good agreement with the model predictions. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. GC/MS method for the determination of volatile organic compounds in waste container headspace using SUMMA{reg_sign} passivated canisters

    Energy Technology Data Exchange (ETDEWEB)

    Crowder, C.A.; Arbon, R.E.; Connolly, M.J.; Evans, R.E. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

    1994-12-31

    The analysis of waste container headspace for volatile organic compounds (VOCs) is required for the eventual storage of mixed hazardous waste, i.e. waste containing a radioactive component and a chemical component, at the Waste Isolation Pilot Plant (WIPP) near Carlsbad, New Mexico. The amount of sample that can be extracted from a waste drum is limited to approximately 250 mL or less, with concentrations of VOCs ranging from parts per billion (volume/volume) to volume percent levels. GC/MS analytical methods available at the inception of this project did not address the analysis of highly concentrated gas samples. Consequently, a method was developed by this lab to deal with the unique problems associated with this type of analysis. This method uses varying sample volumes and combines novel sample preparation techniques along with selected procedures from existing EPA ambient air and waste water methods to quantitate for 23 VOCs.

  3. High-Performance Liquid Chromatographic and High-Performance Thin-Layer Chromatographic Method for the Quantitative Estimation of Dolutegravir Sodium in Bulk Drug and Pharmaceutical Dosage Form.

    Science.gov (United States)

    Bhavar, Girija B; Pekamwar, Sanjay S; Aher, Kiran B; Thorat, Ravindra S; Chaudhari, Sanjay R

    2016-01-01

    Simple, sensitive, precise, and specific high-performance liquid chromategraphic (HPLC) and high-performance thin-layer chromatographic (HPTLC) methods for the determination of dolutegravir sodium in bulk drug and pharmaceutical dosage form were developed and validated. In the HPLC method, analysis of the drug was carried out on the ODS C18 column (150 × 4.6 mm, 5 μm particle size) using a mixture of acetonitrile: water (pH 7.5) in the ratio of 80:20 v/v as the mobile phase at the flow rate 1 mL/min at 260 nm. This method was found to be linear in the concentration range of 5-35 μg/mL. The peak for dolutegravir sodium was observed at 3.0 ± 0.1 minutes. In the HPTLC method, analysis was performed on aluminum-backed plates pre-coated with silica gel G60 F254 using methanol: chloroform: formic acid in the proportion of 8:2:0.5 v/v/v as the mobile phase. This solvent system was found to give compact spots for dolutegravir sodium with the Rf value 0.77 ± 0.01. Densitometric analysis of dolutegravir sodium was carried out in the absorbance mode at 265 nm. Linear regression analysis showed good linearity with respect to peak area in the concentration range of 200-900 ng/spot. The methods were validated for precision, limit of detection (LOD), limit of quantitation (LOQ), accuracy, and specificity. Statistical analysis showed that both of the methods are repeatable and specific for the estimation of the said drug. The methods can be used for routine quality control analysis of dolutegravir sodium.

  4. A method for the analysis of tabun in multisol using gas chromatographic flame photometric detection.

    Science.gov (United States)

    Logan, Thomas P; Allen, Edward D; Way, Mark R; Swift, Austin T; Soni, Sunil-Datta; Koplovitz, Irwin

    2006-01-01

    Preparation and analysis of tabun (GA) solutions are necessary for the continued development of countermeasures to this nerve agent. GA solutions must be stable and compatible for use in the test systems chosen for study; however, GA is very unstable in saline solutions. In the past we have found GA in saline at 2 mg/mL to be stable for a month or less at -70 degrees C, whereas saline solutions of sarin (GB), soman (GD), and cyclosarin (GF) were stable for many months. Previous studies have shown that Multisol (48.5% H(2)O, 40% propylene glycol, 10% ethanol, and 1.5% benzyl alcohol) provides stable solutions of GA. We confirmed the stability of GA in Multisol with phosphorus nuclear magnetic resonance (P horizontal line NMR) and developed a method for the analysis of GA in Multisol using gas chromatographic flame photometric detection (GCFPD) in the phosphorus mode. The GC method used acetonitrile (CH(3)CN) for a dilution solvent because of its miscibility with GA in chloroform (CHCl(3)) standards and GA in Multisol samples at 1% (v/v). Furthermore, the dilutions with CH(3)CN made the phosphorus mode interference peak present in CHCl(3) analytically manageable, reduced the interferences of Multisol in the GC separation, and contributed to a safe and reliable analysis of GA at 20 mug/mL. We demonstrated the stability of GA in Multisol stored for more than a year at 70 degrees C. This method contributes a suitable technique for the preparation and analysis of reliable solutions of GA in nerve agent medical research and demonstrates the extended stability of GA in Multisol.

  5. Development of a dynamic headspace gas chromatography-mass spectrometry method for on-site analysis of sulfur mustard degradation products in sediments.

    Science.gov (United States)

    Magnusson, R; Nordlander, T; Östin, A

    2016-01-15

    Sampling teams performing work at sea in areas where chemical munitions may have been dumped require rapid and reliable analytical methods for verifying sulfur mustard leakage from suspected objects. Here we present such an on-site analysis method based on dynamic headspace GC-MS for analysis of five cyclic sulfur mustard degradation products that have previously been detected in sediments from chemical weapon dumping sites: 1,4-oxathiane, 1,3-dithiolane, 1,4-dithiane, 1,4,5-oxadithiephane, and 1,2,5-trithiephane. An experimental design involving authentic Baltic Sea sediments spiked with the target analytes was used to develop an optimized protocol for sample preparation, headspace extraction and analysis that afforded recoveries of up to 60-90%. The optimized method needs no organic solvents, uses only two grams of sediment on a dry weight basis and involves a unique sample presentation whereby sediment is spread uniformly as a thin layer inside the walls of a glass headspace vial. The method showed good linearity for analyte concentrations of 5-200 ng/g dw, good repeatability, and acceptable carry-over. The method's limits of detection for spiked sediment samples ranged from 2.5 to 11 μg/kg dw, with matrix interference being the main limiting factor. The instrumental detection limits were one to two orders of magnitude lower. Full-scan GC-MS analysis enabled the use of automated mass spectral deconvolution for rapid identification of target analytes. Using this approach, analytes could be identified in spiked sediment samples at concentrations down to 13-65 μg/kg dw. On-site validation experiments conducted aboard the research vessel R/V Oceania demonstrated the method's practical applicability, enabling the successful identification of four cyclic sulfur mustard degradation products at concentrations of 15-308μg/kg in sediments immediately after being collected near a wreck at the Bornholm Deep dumpsite in the Baltic Sea. Copyright © 2015 Elsevier B.V. All

  6. Headspace mass spectrometry methodology: application to oil spill identification in soils

    Energy Technology Data Exchange (ETDEWEB)

    Perez Pavon, J.L.; Garcia Pinto, C.; Moreno Cordero, B. [Universidad de Salamanca, Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias Quimicas, Salamanca (Spain); Guerrero Pena, A. [Universidad de Salamanca, Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias Quimicas, Salamanca (Spain); Laboratorio de Suelos, Plantas y Aguas, Campus Tabasco, Colegio de Postgraduados, Cardenas, Tabasco (Mexico)

    2008-05-15

    In the present work we report the results obtained with a methodology based on direct coupling of a headspace generator to a mass spectrometer for the identification of different types of petroleum crudes in polluted soils. With no prior treatment, the samples are subjected to the headspace generation process and the volatiles generated are introduced directly into the mass spectrometer, thereby obtaining a fingerprint of volatiles in the sample analysed. The mass spectrum corresponding to the mass/charge ratios (m/z) contains the information related to the composition of the headspace and is used as the analytical signal for the characterization of the samples. The signals obtained for the different samples were treated by chemometric techniques to obtain the desired information. The main advantage of the proposed methodology is that no prior chromatographic separation and no sample manipulation are required. The method is rapid, simple and, in view of the results, highly promising for the implementation of a new approach for oil spill identification in soils. (orig.)

  7. Separation and identification of various vulcanization agents and antioxidants in two types of rubber by chromatographic and spectrometric methods.

    Science.gov (United States)

    Chauveau, S; Hamon, M; Leleu, E

    1991-11-01

    The aim of this study was to separate and identify by chromatographic and spectrometric methods, the various allergenic vulcanization agents and antioxidants used in the manufacture of industrial rubber. Specimens of elastomers were manufactured specially for this study. The specificity of the gas chromatographic method developed allows separation of all the manufacturing additives in the selected rubber types after one injection only, even though they belong to extremely varied chemical categories. The GLC method was coupled with mass spectrometry, which permitted identification of the peaks obtained and the study of the fragmentation of the 4 reference products under various conditions. Separation by TLC was performed in parallel on the same extracts, allowing rapid identification of the products tested for, and showed new spots after vulcanization.

  8. Polyphenolic characterization and chromatographic methods for fast assessment of culinary Salvia species from South East Europe.

    Science.gov (United States)

    Cvetkovikj, I; Stefkov, G; Acevska, J; Stanoeva, J Petreska; Karapandzova, M; Stefova, M; Dimitrovska, A; Kulevanova, S

    2013-03-22

    Although the knowledge and use of several Salvia species (Salvia officinalis, Salvia fruticosa, and Salvia pomifera) can be dated back to Greek Era and have a long history of culinary and effective medicinal use, still there is a remarkable interest concerning their chemistry and especially the polyphenolic composition. Despite the demand in the food and pharmaceutical industry for methods for fast quality assessment of the herbs and spices, even now there are no official requirements for the minimum content of polyphenols in sage covered by current regulations neither the European Pharmacopoeia monographs nor the ISO 11165 standard. In this work a rapid analytical method for extraction, characterization and quantification of the major polyphenolic constituents in Sage was developed. Various extractions (infusion - IE; ultrasound-assisted extraction - USE and microwave-assisted extraction - MWE) were performed and evaluated for their effectiveness. Along with the optimization of the mass-detector and chromatographic parameters, the applicability of three different reverse C18 stationary phases (extra-density bonded, core-shell technology and monolith column) for polyphenolics characterization was evaluated. A comprehensive overview of the very variable polyphenolic composition of 118 different plant samples of 68 populations of wild growing culinary Salvia species (S. officinalis: 101; S. fruticosa: 15; S. pomifera: 2) collected from South East Europe (SEE) was performed using HPLC-DAD-ESI-MS(n) and more than 50 different compounds were identified and quantified. With this work the knowledge about polyphenols of culinary Sage was expanded thus the possibility for gaining an insight into the chemodiversity of culinary Salvia species in South East Europe was unlocked. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. A reversed phase liquid chromatographic method for the simultaneous determination of several common penicillins in human serum.

    Science.gov (United States)

    Mendez-Alvarez, E; Soto-Otero, R; Sierra-Paredes, G; Aguilar-Veiga, E; Galan-Valiente, J; Sierra-Marcuño, G

    1991-03-01

    A rapid and sensitive high performance liquid chromatographic method is described for the simultaneous determination of benzylpenicillin, ampicillin, phenoxymethylpenicillin, cloxacillin, dicloxacillin and nafcillin in small samples of human serum. The chromatographic system involves the use of a Spherisorb ODS reversed phase column and a gradient elution with 1 mM ammonium acetate buffer/acetonitrile (from 90:10 to 75:25 in 15 min). Detection and quantification are monitored by UV absorption at 208 nm. The compounds are extracted with dichloromethane, using tetrabutylammonium hydrogen sulfate neutralized with sodium hydroxide and buffered with borate as an ion pairing reagent; beta-hydroxyethyltheophylline is added as an internal standard. Our results show that the method is accurate and reproducible, allowing quantification of serum levels of assayed penicillins (0.5-50 micrograms/mL) without interference from other drugs commonly used in therapy. Recoveries were generally greater than 79.4%.

  10. Microminiature gas chromatographic column

    Science.gov (United States)

    Donaldson, R. W., Jr.

    1972-01-01

    Techniques commonly used for fabrication of integrated circuits are utilized to produce long capillary tubes for microminiature chromatographs. Method involves bonding of flat silicon plate to top of spirally grooved silicon chip to close groove and form capillary column.

  11. A validated liquid chromatographic method for determining folates in vegetables, milk powder, liver, and flour.

    Science.gov (United States)

    Konings, E J

    1999-01-01

    A liquid chromatographic (LC) method was elaborated for determining folates in foods. Folates were extracted by homogenizing in buffer and heat treatment. A portion was incubated with an enzyme preparation containing conjugase, amylase, and protease. After purification by affinity chromatography, folate monoglutamates were determined by reversed-phase LC with fluorescence and diode array detection. Gradient elution with phosphate buffer and acetonitrile was used to separate vitamers. The most abundant folate forms naturally present in foods were detected, including tetrahydrofolic acid, 5-methyltetrahydrofolic acid, and 5-formyltetrahydrofolic acid. 10-Formylfolic acid could be detected by applying a second fluorescence detector. Folic acid, used for fortification, might also be quantitated with this system. The difference between folate concentrations in sample extracts, with and without treatment of conjugase, is a measure of the quantity of polyglutamates in the food matrixes. An additional treatment with conjugase, amylase, and protease reflects the amount of matrix-bound folates. The LC system gave a linear response over the range 0-100 ng/mL. Detection limit for these compounds were 7 pg/mL for tetrahydrofolic acid and 5-methyltetrahydrofolic acid and 59 pg/mL for 10-formylfolic acid (signal-to-noise ratio > or = 3) when 100 microL was injected. Detection limits for 5-formyltetrahydrofolic acid and folic acid were 1 ng/mL. Repeatability relative standard deviation values for separate folates in 3 candidate Certified Reference Materials (CRMs)--mixed vegetables (CRM 485), pig liver (CRM 487), and whole-meal flour (CRM 121)--and a Certified Reference Material milk powder (CRM 421) varied from 3.3 to 21.0% for the concentration range 1.8-1440 micrograms/100 g. Recoveries ranged from 73 to 109%. Use of amylase and protease was advantageous. Use of a commercially available folate-binding protein for cleanup saved time and money and was effective. Results for 5

  12. Diagnosis of bacteraemia by automated head-space capillary gas chromatography.

    OpenAIRE

    Larsson, L; Mårdh, P A; Odham, G; Carlsson, M L

    1982-01-01

    Blood cultures from 196 patients with suspected bacteraemia or septicaemia were analysed by automated head-space gas chromatography, using a 25 m fused silica capillary column, when turbidity indicated growth. Gas chromatography correctly identified 105 cultures as positive and 71 correctly as negative. No false-positive results were obtained. Of the 20 false-negative chromatographic results, Staphylococcus spp accounted for 14. Automated head-space gas chromatography is quicker, easier and m...

  13. Development of a headspace-solid phase microextraction-gas chromatography method to determine organohalogen contamination in drinking water.

    Science.gov (United States)

    Mariani, Maurizio Boccacci; Giannetti, Vanessa; Testani, Elena; D'Aiuto, Virginia

    2012-01-01

    The formation of organohalogen compounds in waters treated by chlorination has drawn increasing scientific attention due to the potentially hazardous health effects of this class of substances. Today, chlorination is the most widely used technology for civil water disinfection. In this study, headspace-solid phase microextraction coupled with GC-electron capture detector was used to determine organohalogen compounds in drinking water sampled from aqueducts and artesian wells in Italy. Experimental parameters, such as sample volume, stirring, salting out, extraction temperature, and extraction time, were evaluated and optimized. The LODs ranged from 1 to 10 ng/L and LOQs from 5 to 50 ng/L. A linear response was confirmed by correlation coefficients ranging from 0.9443 to 0.9999. Quantifiable organohalogen residues were found in 11 water samples, with concentration up to 11.3 +/- 0.5 microg/L for the sum of all trihalomethanes and 0.66 +/- 0.03 microg/L for the sum of trichloroethylene and tetrachloroethylene. These concentrations are lower than the current regulatory limits in Italy.

  14. Gas Chromatograph Method Optimization Trade Study for RESOLVE: 20-meter Column v. 8-meter Column

    Science.gov (United States)

    Huz, Kateryna

    2014-01-01

    RESOLVE is the payload on a Class D mission, Resource Prospector, which will prospect for water and other volatile resources at a lunar pole. The RESOLVE payload's primary scientific purpose includes determining the presence of water on the moon in the lunar regolith. In order to detect the water, a gas chromatograph (GC) will be used in conjunction with a mass spectrometer (MS). The goal of the experiment was to compare two GC column lengths and recommend which would be best for RESOLVE's purposes. Throughout the experiment, an Inficon Fusion GC and an Inficon Micro GC 3000 were used. The Fusion had a 20m long column with 0.25mm internal diameter (Id). The Micro GC 3000 had an 8m long column with a 0.32mm Id. By varying the column temperature and column pressure while holding all other parameters constant, the ideal conditions for testing with each column length in their individual instrument configurations were determined. The criteria used for determining the optimal method parameters included (in no particular order) (1) quickest run time, (2) peak sharpness, and (3) peak separation. After testing numerous combinations of temperature and pressure, the parameters for each column length that resulted in the most optimal data given my three criteria were selected. The ideal temperature and pressure for the 20m column were 95 C and 50psig. At this temperature and pressure, the peaks were separated and the retention times were shorter compared to other combinations. The Inficon Micro GC 3000 operated better at lower temperature mainly due to the shorter 8m column. The optimal column temperature and pressure were 70 C and 30psig. The Inficon Micro GC 3000 8m column had worse separation than the Inficon Fusion 20m column, but was able to separate water within a shorter run time. Therefore, the most significant tradeoff between the two column lengths was peak separation of the sample versus run time. After performing several tests, it was concluded that better

  15. Development and validation of a high performance thin layer chromatographic method for determination of 1, 8-Cineole in Callistemon Citrinus

    OpenAIRE

    Shaha, Archana; Salunkhe, Vijay R

    2014-01-01

    A new, simple, precise, rapid, and selective high performance thin layer chromatographic (HPTLC) method has been developed and validated for the estimation of 1, 8-cineole in volatile oil of leaves of Callistemon citrinus obtained by hydro distillation. The method was validated as per ICH guidelines and can be utilized for routine analysis. The retention factor for 1, 8-cineole was found to be 0.52. The linearity was found to be in the range of 3 μg-12 μg. The recovery obtained for 1, 8-cineo...

  16. Sample Preparation for Headspace GC Analysis of Residual Solvents in Hyaluronic Acid Derivative Fiber

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hoon Joo; Kim, Dong Min; Yang, Jeong Soo [LG life Sciences, Ltd./R and D Park, Daejeon (Korea, Republic of); Kim, Chan Wha [Korea University, Seoul (Korea, Republic of)

    2006-02-15

    The aim of this study is to develop efficient sample preparation method for HS-GC analysis of residual solvents in HA derivative fiber. Compared to direct extraction of residual solvents from HA derivative fiber, the extraction through the hydrolysis of HA derivative fiber by HAse gave more complete and higher reproducible quantification of residual solvent. To validate HS-GC analysis method of residual solvents, specificity, limits of detection and quantification, linearity, accuracy and precision are investigated in the study. HA derivative fiber was hydrolyzed using HAse for headspace gas chromatographic analysis of residual solvents of ethanol, acetone and isopropanol in HA derivative fiber. This study showed that the developed method had specificity, linearity, accuracy and precision. In addition, it demonstrated that HS-GC coupled with matrix-breaking method such as hydrolysis was available for the determination of residual solvents in a matrix like HA derivative fiber.

  17. Efficient quantification of water content in edible oils by headspace gas chromatography with vapour phase calibration.

    Science.gov (United States)

    Xie, Wei-Qi; Gong, Yi-Xian; Yu, Kong-Xian

    2017-11-24

    An automated and accurate headspace gas chromatographic (HS-GC) technique was investigated for rapidly quantifying water content in edible oils. In this method, multiple headspace extraction (MHE) procedures were used to analyse the integrated water content from the edible oil sample. A simple vapour phase calibration technique with an external vapour standard was used to calibrate both the water content in the gas phase and the total weight of water in edible oil sample. After that the water in edible oils can be quantified. The data showed that the relative standard deviation of the present HS-GC method in the precision test was less than 1.13%, the relative differences between the new method and a reference method (i.e. the oven-drying method) were no more than 1.62%. The present HS-GC method is automated, accurate, efficient, and can be a reliable tool for quantifying water content in edible oil related products and research. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  18. Quantitative analysis of total starch content in wheat flour by reaction headspace gas chromatography.

    Science.gov (United States)

    Xie, Wei-Qi; Gong, Yi-Xian; Yu, Kong-Xian

    2017-09-01

    This paper proposed a new reaction headspace gas chromatographic (HS-GC) method for efficiently quantifying the total starch content in wheat flours. A certain weight of wheat flour was oxidized by potassium dichromate in an acidic condition in a sealed headspace vial. The results show that the starch in wheat flour can be completely transferred to carbon dioxide at the given conditions (at 100 °C for 40 min) and the total starch content in wheat flour sample can be indirectly quantified by detecting the CO2 formed from the oxidation reaction. The data showed that the relative standard deviation of the reaction HS-GC method in the precision test was less than 3.06%, and the relative differences between the new method and the reference method (titration method) were no more than 8.90%. The new reaction HS-GC method is automated, accurate, and can be a reliable tool for determining the total starch content in wheat flours in both laboratory and industrial applications. Graphical abstract The total starch content in wheat flour can be indirectly quantified by the GC detection of the CO2 formed from the oxidation reaction between wheat flour and potassium dichromate in an acidic condition.

  19. Molecular Weights of Bovine and Porcine Heparin Samples: Comparison of Chromatographic Methods and Results of a Collaborative Survey

    Directory of Open Access Journals (Sweden)

    Sabrina Bertini

    2017-07-01

    Full Text Available In a collaborative study involving six laboratories in the USA, Europe, and India the molecular weight distributions of a panel of heparin sodium samples were determined, in order to compare heparin sodium of bovine intestinal origin with that of bovine lung and porcine intestinal origin. Porcine samples met the current criteria as laid out in the USP Heparin Sodium monograph. Bovine lung heparin samples had consistently lower average molecular weights. Bovine intestinal heparin was variable in molecular weight; some samples fell below the USP limits, some fell within these limits and others fell above the upper limits. These data will inform the establishment of pharmacopeial acceptance criteria for heparin sodium derived from bovine intestinal mucosa. The method for MW determination as described in the USP monograph uses a single, broad standard calibrant to characterize the chromatographic profile of heparin sodium on high-resolution silica-based GPC columns. These columns may be short-lived in some laboratories. Using the panel of samples described above, methods based on the use of robust polymer-based columns have been developed. In addition to the use of the USP’s broad standard calibrant for heparin sodium with these columns, a set of conditions have been devised that allow light-scattering detected molecular weight characterization of heparin sodium, giving results that agree well with the monograph method. These findings may facilitate the validation of variant chromatographic methods with some practical advantages over the USP monograph method.

  20. A Sensitive Liquid Chromatographic Method for the Analysis of Clarithromycin with Pre-Column Derivatization: Application to a Bioequivalence Study

    Directory of Open Access Journals (Sweden)

    Amir Farshchi

    2009-03-01

    Full Text Available Objective(sA sensitive liquid chromatographic method for the analysis of clarithromycin- a macrolide antibiotic- in human serum, using pre-column derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl is described. Materials and MethodsThe method involved liquid–liquid extraction of the drug and an internal standard (amantadine followed by pre-column derivatization of the analytes with FMOC-Cl. A mixture of 0.05 M phosphate buffer containing triethylamine (2 ml/l; pH 3.8 and methanol (17:83, v/v was used as mobile phase and chromatographic separation was achieved on a Shimpack CLC-ODS column. The eluate was monitored by a fluorescence detector with respective excitation and emission wavelengths of 265 and 315 nm. ResultsThe analytical method was linear over the concentration range of 0.025-10 μg/ml of clarithromycin in human serum with a limit of quantification of 0.025 μg/ml. The assay is sensitive enough to measure drug levels obtained in human single dose studies.ConclusionIn the present method, sensitivity and the running time of analysis have been improved and successfully applied in a bioequivalence study of three different clarithromycin preparations in 12 healthy volunteers.

  1. A review of chromatographic methods for the determination of water- and fat-soluble vitamins in biological fluids.

    Science.gov (United States)

    Karaźniewicz-Łada, Marta; Główka, Anna

    2016-01-01

    Vitamins are an essential element of nutrition and thus contribute to human health. Vitamins catalyze many biochemical reactions and their lack or excess can cause health problems. Therefore, monitoring vitamin concentrations in plasma or other biological fluids may be useful in the diagnosis of various disorders as well as in the treatment process. Several chromatographic methods have been developed for the determination of these compounds in biological samples, including high-performance liquid chromatography with UV and fluorescence detection. Recently, high-performance liquid chromatography with tandem mass spectrometry methods have been widely used for the determination of vitamins in complex matrices because of their high sensitivity and selectivity. This method requires preconditioning of samples for analysis, including protein precipitation and/or various extraction techniques. The choice of method may depend on the desired cost, convenience, turnaround time, specificity, and accuracy of the information to be obtained. This article reviews the recently reported chromatographic methods used for determination of vitamins in biological fluids. Relevant papers published mostly during the last 5 years were identified by an extensive PubMed search using appropriate keywords. Particular attention was given to the preparation steps and extraction techniques. This report may be helpful in the selection of procedures that are appropriate for certain types of biological materials and analytes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Headspace thin-film microextraction coupled with surface-enhanced Raman scattering as a facile method for reproducible and specific detection of sulfur dioxide in wine.

    Science.gov (United States)

    Deng, Zhuo; Chen, Xuexu; Wang, Yiru; Fang, Enhua; Zhang, Zhigang; Chen, Xi

    2015-01-06

    By coupling thin-film microextraction (TFME) with surface-enhanced Raman scattering (SERS), a facile method was developed for the determination of sulfur dioxide (SO2), the most effective food additive in winemaking technology. The TFME substrate was made by free settling of sea urchin-like ZnO nanomaterials on a glass sheet. The headspace sampling (HS) procedure for SO2 was performed in a simple homemade device, and then the SO2 was determined using SERS after uniformly dropping or spraying a SERS-active substrate (gold nanoparticles, AuNPs) onto the surface of the TFME substrate. A reproducible and strong SERS response of the SO2 absorbed onto the ZnO substrate was obtained. After condition optimization, the SERS signal intensity at a shift of 600 cm(-1) and the SO2 concentration showed a good linearity in the range of 1-200 μg/mL, and the linear correlation coefficient was 0.992. The detection limit for SO2 was found to be 0.1 μg/mL. The HS-TFME-SERS method was applied for the determination of SO2 in wine, and the results obtained agreed very well with those obtained using the traditional distillation and titration method. Analysis of variance and Student t test show that there is no significant difference between the two methods, indicating that the newly developed method is fast, convenient, sensitive and has selective characteristics in the determination of SO2 in wine.

  3. Ultrasensitive determination of highly polar trimethyl phosphate in environmental water by molecularly imprinted polymeric fiber headspace solid-phase microextraction.

    Science.gov (United States)

    Cai, Cuicui; Zhang, Pengcheng; Deng, Jiali; Zhou, Hongbin; Cheng, Jing

    2017-12-14

    A sensitive, accurate and cost effective method for the quantification of trimethyl phosphate, which is highly polar and volatile, in environmental water is presented. Trimethyl phosphate was headspace solid-phase microextracted on a molecularly imprinted polymeric fiber, and then the fiber was thermally desorbed in the gas chromatograph injector, and the compound was determined. The trimethyl phosphate imprinted polymeric fiber was prepared by copolymerization in a fused silica capillary tube and obtained by removal of the wall of fused silica capillary tube. The monolithic fiber displayed good selectivity toward trimethyl phosphate among its structural analogues. It was thermally stable up to 320°C so that it can withstand the high temperature of the gas chromatograph injector for desorption. The factors influencing the performance of its headspace solid phase microextraction were studied. Under the optimal conditions, the method for quantification of trimethyl phosphate in environmental water was well developed. It exhibited significant linearity, the lowest limit of quantification to date and good recoveries. Using this method, trimethyl phosphate was detected out in five out of seven environmental water samples at concentration levels from 0.28 to 1.22 μg L-1 , illustrating the heavy pollution of trimethyl phosphate in environmental water. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  4. Solvent-free microwave extraction coupled with headspace single-drop microextraction of essential oils from flower of Eugenia caryophyllata Thunb.

    Science.gov (United States)

    Jiang, Chunzhu; Sun, Ying; Zhu, Xiaonan; Gao, Yan; Wang, Liying; Wang, Jian; Wu, Liwei; Song, Daqian

    2010-09-01

    Solvent-free microwave extraction coupled with headspace single-drop microextraction was developed for extracting the essential oils from Eugenia caryophyllata Thunb. Carbonyl iron powders were mixed with the sample to extract essential oils from the dried plant materials and single-drop solvent was used to simultaneously extract essential oils from the headspace. The single-drop of decane was suspended from the tip of a microsyringe and exposed to the headspace above the sample. After the extraction was finished, the single-drop was injected into gas chromatographic system and analyzed by GC-MS. The effects of the experimental parameters, including microwave power, microwave irradiation time, the ratio of carbonyl iron powder to sample, extraction solvent, single-drop volume and extraction time, were investigated. Sixteen compounds in the essential oils of E. caryophyllata T. were obtained and identified. The constituents of essential oils obtained by hydro-distillation and solvent-free microwave extraction-headspace single-drop microextraction were not obviously different. Compared with hydro-distillation, the proposed method required shorter extraction time and less amount of the sample.

  5. Simple and rapid high-performance liquid chromatographic method for the determination of aspartame and its metabolites in foods.

    Science.gov (United States)

    Gibbs, B F; Alli, I; Mulligan, C N

    1996-02-23

    A method for the determination of aspartame (N-L-alpha-aspartyl-L-phenylalanine methyl ester) and its metabolites, applicable on a routine quality assurance basis, is described. Liquid samples (diet Coke, 7-Up, Pepsi, etc.) were injected directly onto a mini-cartridge reversed-phase column on a high-performance liquid chromatographic system, whereas solid samples (Equal, hot chocolate powder, pudding, etc.) were extracted with water. Optimising chromatographic conditions resulted in resolved components of interest within 12 min. The by-products were confirmed by mass spectrometry. Although the method was developed on a two-pump HPLC system fitted with a diode-array detector, it is straightforward and can be transformed to the simplest HPLC configuration. Using a single-piston pump (with damper), a fixed-wavelength detector and a recorder/integrator, the degradation of products can be monitored as they decompose. The results obtained were in harmony with previously reported tedious methods. The method is simple, rapid, quantitative and does not involve complex, hazardous or toxic chemistry.

  6. An innovative, simple, fast, and less toxic high-performance liquid chromatographic method for determination of prednisone in capsules

    Directory of Open Access Journals (Sweden)

    Pedro Henrique Reis da Silva

    2017-06-01

    Full Text Available ABSTRACT Prednisone is an anti-inflammatory steroid drug widely used in clinical practice. However, no high-performance liquid chromatographic (HPLC method has been described in the literature for the determination of prednisone in capsules until now. Thus, an HPLC method was developed using a C18 (250x4.0, 5 µm column, with methanol:water (70:30 as mobile phase at a flow rate of 1 mL/min and detection at 240 nm. The developed method was validated following current Brazilian legislation. Additionally, linearity was assessed by evaluating the assumptions of normality, homoscedasticity, and independency of residuals, and the fit to the linear model. The method showed linearity (r2>0.99 over the range of 14.0-26.0 µg/mL, selectivity, precision (RSD<2.0%, robustness, and accuracy (average recovery of 100.05%. The chromatographic procedure was applied for assay and uniformity content determination of three different batches of prednisone capsules, showing to be suitable for their quality control.

  7. An accurate method for microanalysis of carbon monoxide in putrid postmortem blood by head-space gas chromatography-mass spectrometry (HS/GC/MS).

    Science.gov (United States)

    Hao, Hongxia; Zhou, Hong; Liu, Xiaopei; Zhang, Zhong; Yu, Zhongshan

    2013-06-10

    Carbon monoxide (CO) may be the cause of more than half the fatal poisonings reported in many countries, with some of these cases under-reported or misdiagnosed by medical professionals. Therefore, an accurate and reliable analytical method to measure blood carboxyhemoglobin level (COHb%), in the 1% to lethal range, is essential for correct diagnosis. Herein a method was established, i.e. head-space gas chromatography-mass spectrometry (HS/GC/MS) that has numerous advantages over other techniques, such as UV spectrometry, for determination of COHb%. There was a linear relationship (R(2)=0. 9995) between the peak area for CO and the COHb% in blood. Using a molecular sieve-packed column, CO levels in the air down to 0.01% and COHb% levels in small blood samples down to 0.2% could be quantitated rapidly and accurately. Furthermore, this method showed good reproducibility with a relative standard deviation for COHb% of <1%. Therefore, this technique provides an accurate and reliable method for determining CO and COHb% levels and may prove useful for investigation of deaths potentially related to CO exposure. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  8. Determination of Cyanide in Biological and Non-biological Matrices by Headspace Gas Chromatography coupled to Flame- Ionization Detector

    Directory of Open Access Journals (Sweden)

    Humera Shafi

    2015-05-01

    Full Text Available A simple, rapid and reliable method for quantitation of cyanide was developed on a headspace gas chromatograph coupled to a flame ionization detector using a HP-Innovax (Polyethylene glycol bonded column on an Agilent 7890A GC. Cyanide in blood or other matrices was liberated by conversion of potassium cyanide to the volatile hydrogen cyanide (HCN through addition of 5N sulfuric acid in a headspace vial and analyzed using an Agilent G1888 headspace auto-sampler. HCN gas diffuses into the headspace above the specimen in a sealed vial based on Henry’s Law of partial pressure. This method showed good linearity (r2= 0.9996 in the range of 8.0-60.0 μg/mL with 1.0 μg/mL of HCN as the limit of detection. The accuracy of the method at three different concentrations (8.0, 16.0, 50.0 μg/ mL of HCN was in the range of 95.0% to 101.9% and inter-day precision (%CV ranged from 1.3% to 3.8%. Identical calibration curves with a coefficient of correlation above 0.990 were obtained when blood, gastric contents, liver tissue homogenate, urine and water were used as calibration standard matrices. Therefore, a single calibration curve is sufficient for diverse matrices and preparation of matrix-matched standards is not required. The method showed successful quantitation of Hydrogen cyanide in gastric contents, which is one of the most variable matrices in forensic toxicology. The method is well adopted for postmortem specimens because of its wide linear range, adaptability to various matrices, ease and rapidity of use.

  9. Determination of losartan potassium, quinapril hydrochloride and hydrochlorothiazide in pharmaceutical preparations using derivative spectrophotometry and chromatographic-densitometric method.

    Science.gov (United States)

    Stolarczyk, Mariusz; Maślanka, Anna; Apola, Anna; Krzek, Jan

    2013-01-01

    Two methods, spectrophotometric and chromatographic-densitometric ones, were developed for determination of losartan potassium, quinapril hydrochloride and hydrochlorothiazide in pharmaceutical preparations. Spectrophotometric method involved derivative spectrophotometry and zero order spectrophotometry. The measurements were carried out at lambda = 224.0 nm for quinapril, lambda = 261.0 nm for hydrochlorothiazide and lambda = 270.0 nm for losartan when the derivative spectrophotometry was applied and lambda = 317.0 nm when zero order spectrophotometry was applied for the determination of hydrochlorothiazide. In chromatographic-densitometric studies high performance thin layer chromatography (HPTLC) plates were used as stationary phase and a mixture of solvents n-butanol : acetic acid : water (15 : 5 : 1, v/v/v) as mobile phase. Under the established conditions good resolution of examined constituents was obtained. Retardation factor for quinapril hydrochloride was R(f) - 0.70, for losartan potassium R(f) - 0.85 and for hydrochlorothiazide R(f) - 0.78. The developed methods are characterized by high sensitivity and accuracy. For quantitative analysis, densitometric measurements were carried out at lambda = 218.0 nm for quinapril, lambda = 275.0 nm for hydrochlorothiazide and = 232.0 nm for losartan.

  10. Innovative method for carbon dioxide determination in human postmortem cardiac gas samples using headspace-gas chromatography-mass spectrometry and stable labeled isotope as internal standard.

    Science.gov (United States)

    Varlet, V; Smith, F; de Froidmont, S; Dominguez, A; Rinaldi, A; Augsburger, M; Mangin, P; Grabherr, S

    2013-06-19

    A novel approach to measure carbon dioxide (CO2) in gaseous samples, based on a precise and accurate quantification by (13)CO2 internal standard generated in situ is presented. The main goal of this study was to provide an innovative headspace-gas chromatography-mass spectrometry (HS-GC-MS) method applicable in the routine determination of CO2. The main drawback of the GC methods discussed in the literature for CO2 measurement is the lack of a specific internal standard necessary to perform quantification. CO2 measurement is still quantified by external calibration without taking into account analytical problems which can often occur considering gaseous samples. To avoid the manipulation of a stable isotope-labeled gas, we have chosen to generate in situ an internal labeled standard gas ((13)CO2) on the basis of the stoichiometric formation of CO2 by the reaction of hydrochloric acid (HCl) with sodium hydrogen carbonate (NaH(13)CO3). This method allows a precise measurement of CO2 concentration and was validated on various human postmortem gas samples in order to study its efficiency. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Analysis of n-alkanes in water samples by means of headspace solvent microextraction and gas chromatography.

    Science.gov (United States)

    Zanjani, Mohammadreza Khalili; Yamini, Yadollah; Shariati, Shahab

    2006-08-25

    A simple and efficient headspace solvent microextraction (HSME) was developed for the simultaneous determination of the trace concentrations of some n-alkanes in water samples. Therefore, a microdrop of an organic solvent was extruded from the needle tip of a gas chromatographic syringe to the headspace above the surface of the solution in a sealed vial. Then the volatile organic compounds are extracted and concentrated in the microdrop. Next, the microdrop was retracted into the microsyringe and injected directly into the gas chromatograph. Experimental parameters which control the performance of HSME such as the type of microextraction solvent, organic drop and sample volume, sample stirring rate, sample solution and microsyringe needle temperatures, salt addition and exposure time profiles were investigated and optimized. Finally, the enrichment factor, dynamic linear range (DLR), limit of detection (LOD) and precision of the method were evaluated. Using optimum extraction conditions, good linearity with correlation coefficients in the range of 0.995alkanes in different types of natural water samples and acceptable recoveries were obtained. The results demonstrated that HSME is a rapid, accurate and effective sample preparation method and could be successfully applied for the determination of n-alkanes in water samples.

  12. Determination of dissolved methane in natural waters using headspace analysis with cavity ring-down spectroscopy.

    Science.gov (United States)

    Roberts, Hannah M; Shiller, Alan M

    2015-01-26

    Methane (CH4) is the third most abundant greenhouse gas (GHG) but is vastly understudied in comparison to carbon dioxide. Sources and sinks to the atmosphere vary considerably in estimation, including sources such as fresh and marine water systems. A new method to determine dissolved methane concentrations in discrete water samples has been evaluated. By analyzing an equilibrated headspace using laser cavity ring-down spectroscopy (CRDS), low nanomolar dissolved methane concentrations can be determined with high reproducibility (i.e., 0.13 nM detection limit and typical 4% RSD). While CRDS instruments cost roughly twice that of gas chromatographs (GC) usually used for methane determination, the process presented herein is substantially simpler, faster, and requires fewer materials than GC methods. Typically, 70-mL water samples are equilibrated with an equivalent amount of zero air in plastic syringes. The equilibrated headspace is transferred to a clean, dry syringe and then drawn into a Picarro G2301 CRDS analyzer via the instrument's pump. We demonstrate that this instrument holds a linear calibration into the sub-ppmv methane concentration range and holds a stable calibration for at least two years. Application of the method to shipboard dissolved methane determination in the northern Gulf of Mexico as well as river water is shown. Concentrations spanning nearly six orders of magnitude have been determined with this method. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Liquid chromatographic methods for the quantification of catecholamines and their metabolites in several biological samples--a review.

    Science.gov (United States)

    Bicker, Joana; Fortuna, Ana; Alves, Gilberto; Falcão, Amílcar

    2013-03-20

    The measurement of catecholamines and their metabolites in biological samples remains a current analytical challenge, in spite of the great diversity of methodologies that have been developed throughout the years. High-performance liquid chromatography is the standard method for their separation and quantification in biological samples, either coupled with electrochemical, fluorescence, chemiluminescence or mass spectrometry detection. This review summarizes the most important physicochemical properties of catecholamines, the wide panoply of sample preparation techniques and the main issues to consider during the development of chromatographic methods. The major difficulties encountered during the optimization of these procedures are related with the high tendency of catecholamines to oxidize and the very low quantities at which they exist in biological matrices. Herein, the most important aspects that ought to be considered during collection, treatment and storage of fluid and tissue samples intended for catecholamine analysis are underlined, the chromatographic conditions are compared and the technical advantages and limitations of each detection system are discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. A New Method for the Fast Analysis of Trihalomethanes in Tap and Recycled Waters Using Headspace Gas Chromatography with Micro-Electron Capture Detection

    Science.gov (United States)

    Alexandrou, Lydon D.; Meehan, Barry J.; Morrison, Paul D.; Jones, Oliver A. H.

    2017-01-01

    Chemical disinfection of water supplies brings significant public health benefits by reducing microbial contamination. The process can however, result in the formation of toxic compounds through interactions between disinfectants and organic material in the source water. These new compounds are termed disinfection by-products (DBPs). The most common are the trihalomethanes (THMs) such as trichloromethane (chloroform), dichlorobromomethane, chlorodibromomethane and tribromomethane (bromoform); these are commonly reported as a single value for total trihalomethanes (TTHMs). Analysis of DBPs is commonly performed via time- and solvent-intensive sample preparation techniques such as liquid–liquid and solid phase extraction. In this study, a method using headspace gas chromatography with micro-electron capture detection was developed and applied for the analysis of THMs in drinking and recycled waters from across Melbourne (Victoria, Australia). The method allowed almost complete removal of the sample preparation step whilst maintaining trace level detection limits (>1 ppb). All drinking water samples had TTHM concentrations below the Australian regulatory limit of 250 µg/L but some were above the U.S. EPA limit of 60 µg/L. The highest TTHM concentration was 67.2 µg/L and lowest 22.9 µg/L. For recycled water, samples taken directly from treatment plants held significantly higher concentrations (153.2 µg/L TTHM) compared to samples from final use locations (4.9–9.3 µg/L). PMID:28505068

  15. A comparative study of three tissue-cultured Dendrobium species and their wild correspondences by headspace gas chromatography–mass spectrometry combined with chemometric methods

    Directory of Open Access Journals (Sweden)

    Nai-Dong Chen

    2016-10-01

    Full Text Available Plant tissue culture technique is widely used in the conservation and utilization of rare and endangered medicinal plants and it is crucial for tissue culture stocks to obtain the ability to produce similar bioactive components as their wild correspondences. In this paper, a headspace gas chromatography–mass spectrometry method combined with chemometric methods was applied to analyze and evaluate the volatile compounds in tissue-cultured and wild Dendrobium huoshanense Cheng and Tang, Dendrobium officinale Kimura et Migo and Dendrobium moniliforme (Linn. Sw. In total, 63 volatile compounds were separated, with 53 being identified from the three Dendrobium spp. samples. Different provenances of Dendrobiums had characteristic chemicals and showed remarkable quantity discrepancy of common compositions. The similarity evaluation disclosed that the accumulation of volatile compounds in Dendrobium samples might be affected by their provenance. Principal component analysis showed that the first three components explained 85.9% of data variance, demonstrating a good discrimination between samples. Gas chromatography–mass spectrometry techniques, combined with chemometrics, might be an effective strategy for identifying the species and their provenance, especially in the assessment of tissue-cultured Dendrobium quality for use in raw herbal medicines.

  16. A New Method for the Fast Analysis of Trihalomethanes in Tap and Recycled Waters Using Headspace Gas Chromatography with Micro-Electron Capture Detection

    Directory of Open Access Journals (Sweden)

    Lydon D. Alexandrou

    2017-05-01

    Full Text Available Chemical disinfection of water supplies brings significant public health benefits by reducing microbial contamination. The process can however, result in the formation of toxic compounds through interactions between disinfectants and organic material in the source water. These new compounds are termed disinfection by-products (DBPs. The most common are the trihalomethanes (THMs such as trichloromethane (chloroform, dichlorobromomethane, chlorodibromomethane and tribromomethane (bromoform; these are commonly reported as a single value for total trihalomethanes (TTHMs. Analysis of DBPs is commonly performed via time- and solvent-intensive sample preparation techniques such as liquid–liquid and solid phase extraction. In this study, a method using headspace gas chromatography with micro-electron capture detection was developed and applied for the analysis of THMs in drinking and recycled waters from across Melbourne (Victoria, Australia. The method allowed almost complete removal of the sample preparation step whilst maintaining trace level detection limits (>1 ppb. All drinking water samples had TTHM concentrations below the Australian regulatory limit of 250 µg/L but some were above the U.S. EPA limit of 60 µg/L. The highest TTHM concentration was 67.2 µg/L and lowest 22.9 µg/L. For recycled water, samples taken directly from treatment plants held significantly higher concentrations (153.2 µg/L TTHM compared to samples from final use locations (4.9–9.3 µg/L.

  17. A New Method for the Fast Analysis of Trihalomethanes in Tap and Recycled Waters Using Headspace Gas Chromatography with Micro-Electron Capture Detection.

    Science.gov (United States)

    Alexandrou, Lydon D; Meehan, Barry J; Morrison, Paul D; Jones, Oliver A H

    2017-05-15

    Chemical disinfection of water supplies brings significant public health benefits by reducing microbial contamination. The process can however, result in the formation of toxic compounds through interactions between disinfectants and organic material in the source water. These new compounds are termed disinfection by-products (DBPs). The most common are the trihalomethanes (THMs) such as trichloromethane (chloroform), dichlorobromomethane, chlorodibromomethane and tribromomethane (bromoform); these are commonly reported as a single value for total trihalomethanes (TTHMs). Analysis of DBPs is commonly performed via time- and solvent-intensive sample preparation techniques such as liquid-liquid and solid phase extraction. In this study, a method using headspace gas chromatography with micro-electron capture detection was developed and applied for the analysis of THMs in drinking and recycled waters from across Melbourne (Victoria, Australia). The method allowed almost complete removal of the sample preparation step whilst maintaining trace level detection limits (>1 ppb). All drinking water samples had TTHM concentrations below the Australian regulatory limit of 250 µg/L but some were above the U.S. EPA limit of 60 µg/L. The highest TTHM concentration was 67.2 µg/L and lowest 22.9 µg/L. For recycled water, samples taken directly from treatment plants held significantly higher concentrations (153.2 µg/L TTHM) compared to samples from final use locations (4.9-9.3 µg/L).

  18. Headspace solid-phase microextraction gas chromatography-mass spectrometry method for the identification of cosmetic ingredients causing delamination of packagings.

    Science.gov (United States)

    Ortiz, Gustavo; Tena, María Teresa

    2006-01-06

    A headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) method using a 75 microm Carboxen polydimethylsiloxane fibre was used to identify volatile compounds of cosmetic formulations responsible for causing loss of adhesion between layers of multilayer packagings. To obtain the sample, the sachet with the product was kept in an oven at 40 degrees C in order to favour the migration of the aggressive compounds to the inner layers. Then the sachet was manually delaminated and the aluminium/polyester and polyethylene layers were analysed. The cosmetic product was also analysed by HS-SPME-GC-MS. Several compounds used in the cosmetic industry such as perfumes or fixing agents were detected in the inner layers of the laminated material, showing the migration of them through the layer in contact with the product (polyethylene). Phenoxy ethanol, beta-linalool, menthol and p-propenylanisole are suspected to be responsible for the loss of adhesion. In order to provide a complete overview of the cause of the aforementioned phenomenon, the packaging material was exposed to the cosmetic products in order to measure the decrease of the adhesion strength with time. It was observed that the product with a higher phenoxy ethanol concentration caused a higher loss of adhesion strength. The results obtained showed that this method is suitable for identifying aggressive compounds in cosmetic products, as well as for giving prior information about which products may be problematic for packaging in sachets.

  19. Development and validation of a high performance thin layer chromatographic method for determination of 1, 8-Cineole in Callistemon Citrinus.

    Science.gov (United States)

    Shaha, Archana; Salunkhe, Vijay R

    2014-04-01

    A new, simple, precise, rapid, and selective high performance thin layer chromatographic (HPTLC) method has been developed and validated for the estimation of 1, 8-cineole in volatile oil of leaves of Callistemon Citrinus obtained by hydro distillation. The method was validated as per ICH guidelines and can be utilized for routine analysis. The retention factor for 1, 8-cineole was found to be 0.52. The linearity was found to be in the range of 3 μg-12 μg. The recovery obtained for 1, 8-cineole was 98%, which is satisfactory. The result obtained in validation indicate the accuracy, reproducibility, and reliability of the developed HPTLC method for determination of 1, 8-cineole.

  20. Microwave-assisted headspace single-drop microextration of chlorobenzenes from water samples

    Energy Technology Data Exchange (ETDEWEB)

    Vidal, Lorena [Departamento de Quimica Analitica, Nutricion y Bromatologia, Universidad de Alicante, P.O. Box 99, E-03080 Alicante (Spain); Domini, Claudia E. [Departamento de Quimica Analitica, Nutricion y Bromatologia, Universidad de Alicante, P.O. Box 99, E-03080 Alicante (Spain); Grane, Nuria [Departamento de Quimica Analitica, Nutricion y Bromatologia, Universidad de Alicante, P.O. Box 99, E-03080 Alicante (Spain); Psillakis, Elefteria [Department of Environmental Engineering, Technical University of Crete, Polytechneioupolis, GR-73100 Chania, Crete (Greece); Canals, Antonio [Departamento de Quimica Analitica, Nutricion y Bromatologia, Universidad de Alicante, P.O. Box 99, E-03080 Alicante (Spain)]. E-mail: a.canals@ua.es

    2007-05-29

    A one-step and in-situ sample preparation method used for quantifying chlorobenzene compounds in water samples has been developed, coupling microwave and headspace single-drop microextraction (MW-HS-SDME). The chlorobenzenes in water samples were extracted directly onto an ionic liquid single-drop in headspace mode under the aid of microwave radiation. For optimization, a Plackett-Burman screening design was initially used, followed by a mixed-level factorial design. The factors considered were: drop volume, aqueous sample volume, stirring speed, ionic strength, extraction time, ionic liquid type, microwave power and length of the Y-shaped glass-tube. The optimum experimental conditions found from this statistical evaluation were: a 5 {mu}L microdrop of 1-hexyl-3-methylimidazolium hexafluorophosphate exposed for 20 min to the headspace of a 30 mL aqueous sample, irradiated by microwaves at 200 W and placed in a 50 mL spherical flask connected to a 25 cm Y-shaped glass-tube. Under the optimised experimental conditions, the response of a high performance liquid chromatographic system was found to be linear over the range studied and with correlation coefficients ranging between 0.9995 and 0.9999. The method showed a good level of repeatability, with relative standard deviations varying between 2.3 and 8.3% (n = 5). Detection limits were found in the low {mu}g L{sup -1} range varying between 0.016 and 0.039 {mu}g L{sup -1}. Overall, the performance of the proposed method demonstrated the favourable effect of microwave sample irradiation upon HS-SDME. Finally, recovery studies from different types of environmental water samples revealed that matrix had little effect upon extraction.

  1. A gas/liquid chromatographic-mass spectrometric method for the rapid screening of 250 pesticides in aqueous matrices

    Energy Technology Data Exchange (ETDEWEB)

    Chandramouli, B.; Harvan, D.; Brittain, S.; Hass, R. [Eno River Labs, LLC. Durham, NC (United States)

    2004-09-15

    Pesticide residues in food present a potentially serious and significant cause for concern. Many pesticides have been associated with significant health effects to the nervous and endocrine systems and some have been deemed carcinogenic. There are many well-established techniques for pesticide analysis. However, commercial pesticide methods have traditionally only been available for specific pesticide families, such as chlorinated pesticides or herbicides, and at detection limits ranging from 0.05 ppb to 1 ppm in aqueous matrices. Techniques that can quickly screen for the presence/absence of pesticide residues in food matrices are critical in ensuring the safety of food and water. This paper outlines a combined Gas Chromatographic-High Resolution Mass Spectrometric (GC-HRMS) and Liquid Chromatographic Tandem Mass Spectrometric (LC-MS/MS) screening assay for 250 pesticides that was developed for use in water, and soda samples at screening levels ranging from 0.1-5 ppb. The pesticides selected have been identified by the European Union as being of concern and the target of possible legislation. The list encompasses a variety of pesticide classes and compound groupings.

  2. Multivariate optimization of a headspace solid-phase microextraction method followed by gas chromatography with mass spectrometry for the determination of terpenes in Nicotiana langsdorffii.

    Science.gov (United States)

    Ardini, Francisco; Carro, Marina Di; Abelmoschi, Maria Luisa; Grotti, Marco; Magi, Emanuele

    2014-07-01

    A simple and sensitive procedure based on headspace solid-phase microextraction and gas chromatography with mass spectrometry was developed for the determination of five terpenes (α-pinene, limonene, linalool, α-terpineol, and geraniol) in the leaves of Nicotiana langsdorffii. The microextraction conditions (extraction temperature, equilibration time, and extraction time) were optimized by means of a Doehlert design. The experimental design showed that, for α-pinene and limonene, a low temperature and a long extraction time were needed for optimal extraction, while linalool, α-terpineol, and geraniol required a high temperature and a long extraction time. The chosen compromise conditions were temperature 60°C, equilibration time 15 min and extraction time 50 min. The main analytical figures of the optimized method were evaluated; LODs ranged from 0.07 ng/g (α-pinene) to 8.0 ng/g (geraniol), while intraday and interday repeatability were in the range 10-17% and 9-13%, respectively. Finally, the procedure was applied to in vitro wild-type and transgenic specimens of N. langsdorffii subjected to abiotic stresses (chemical and heat stress). With the exception of geraniol (75-374 ng/g), low concentration levels of terpenes were measured (ng/g level or lower); some interesting variations in terpene concentration induced by abiotic stress were observed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Optimisation of a headspace solid-phase microextraction method for the direct determination of chloroanisoles related to cork taint in red wine.

    Science.gov (United States)

    Martínez-Uruñuela, Almudena; González-Sáiz, José María; Pizarro, Consuelo

    2004-11-12

    One of the most critical problems in the enological industry is associated with cork taint. The main compounds responsible for this off-flavour are some chloroanisoles: 2,4,6-trichloroanisole (TCA), 2,3,4,6-tetrachloroanisole (TECA) and pentachloroanisole (PCA). Headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography-electron capture detection has been used for the direct determination of these chloroanisoles in wine samples. After the evaluation of some parameters (desorption conditions and salt addition) that affect extraction efficiency, a screening study of six types of fibres and five extraction temperatures was performed. Then, a Doehlert matrix including the exposure time, temperature and Vs (sample volume)/Vt (total volume) ratio as experimental factors was proposed. According to the results of this design and the kinetic profiles evaluated, an analytical procedure based on HS-SPME was optimised and validated. This method can be used for the simultaneous determination at the low ng/l level of all chloroanisoles involved in cork taint, and not only TCA, which is the only compound found in the literature when SPME is proposed as the analytical technique.

  4. Determination of aliphatic amines in water by gas chromatography using headspace solvent microextraction.

    Science.gov (United States)

    Kaykhaii, Massoud; Nazari, Saeed; Chamsaz, Mahmood

    2005-01-15

    The possibility of applying headspace microextraction into a single drop for the determination of amines in aqueous solutions is demonstrated. A 1mul drop of benzyl alcohol containing 2-butanone as an internal standard was suspended from the tip of a micro syringe needle over the headspace of stirred sample solutions for extraction. The drop was then injected directly into a GC. The total chromatographic determination was less than 10min. Optimization of experimental conditions (sampling time, sampling temperature, stirring rate, ionic strength of the solution, concentration of reagents, time of extraction and organic drop volume) with respect to the extraction efficiency were investigated and the linear range and the precision were also examined. Calibration curves yielded good linearity and concentrations down to 2.5ngml(-1) were detectable with R.S.D. values ranging from 6.0 to 12.0%. Finally, the method was successfully applied to the extraction and determination of amines in tap and river water samples. This system represents an inexpensive, fast, simple and precise sample cleanup and preconcentration method for the determination of volatile organic compounds at trace levels.

  5. Development of liquid chromatographic methods for the determination of phytosterols in Standard Reference Materials containing saw palmetto.

    Science.gov (United States)

    Bedner, Mary; Schantz, Michele M; Sander, Lane C; Sharpless, Katherine E

    2008-05-23

    Liquid chromatographic (LC) methods using atmospheric pressure chemical ionization/mass spectrometric (APCI-MS) detection were developed for the separation and analysis of the phytosterols campesterol, cycloartenol, lupenone, lupeol, beta-sitosterol, and stigmasterol. Brassicasterol and cholesterol were also included for investigation as internal standards. The methods were used to identify and quantify the phytosterols in each of two Serenoa repens (saw palmetto) Standard Reference Materials (SRMs) developed by the National Institute of Standards and Technology (NIST). Values obtained by LC-MS were compared to those obtained using the more traditional approach of gas chromatography with flame ionization detection. This is the first reported use of LC-MS to determine phytosterols in saw palmetto dietary supplement materials.

  6. Development and validation of a rapid ultra high pressure liquid chromatographic method for the determination of methylxanthines in herbal infusions.

    Science.gov (United States)

    Zacharis, Constantinos K; Kika, Fotini S; Tzanavaras, Paraskevas D; Fytianos, Konstantinos

    2013-05-15

    An ultra high pressure liquid chromatographic method coupled with diode array detector (UHPLC-DAD) has been developed and validated for the fast separation and determination of three major methylxanthines, i.e., caffeine, theophylline and theobromine, in various herbal beverages. Isocratic elution using 0.1vol% formic acid/CH3OH (92.5:7.5, v/v) enabled the completion of the separation cycle in less than 3min using a flow rate of 0.7mL/min and a column temperature of 50°C. Validation of the method included linearity (0.5-50mg/L), limits of detection (12-35μg/L) and quantification (40-120μg/L), precision, matrix effect and accuracy. The percent recoveries ranged between 90 and 108%. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Validation of an analytical method for analysis of cannabinoids in hair by headspace solid-phase microextraction and gas chromatography-ion trap tandem mass spectrometry.

    Science.gov (United States)

    Emídio, Elissandro Soares; Prata, Vanessa de Menezes; Dórea, Haroldo Silveira

    2010-06-18

    The development of an analytical method for the determination of Delta(9)-tetrahydrocannabinol (THC), cannabidiol (CBD) and cannabinol (CBN) in samples of human hair is described. Samples were subjected to a procedure based on the combination of headspace solid-phase microextraction (HS-SPME) with gas chromatography linked with mass spectrometry operating in tandem mode (GC-MS/MS). A 10 mg aliquot of sample was firstly decontaminated using petroleum ether, deionized water and dichloromethane (2 mL of each solvent), for 10 min under sonication, and then digested in alkaline solution (1 mol L(-1) NaOH). The method variables evaluated were pH, mass of hair, fiber type, extraction temperature, desorption time, ionic strength, pre-equilibrium time and extraction time. Parameters concerning operation of the tandem mode MS/MS were also assessed and optimized. Validation of the method demonstrated excellent linearity in the range 0.1-8.0 ng mg(-1), with regression coefficients better than 0.994. Precision was determined using two different concentrations (upper and lower limits of the linear range), and RSD values were between 6.6 and 16.4%. Absolute recoveries (measured in triplicate) were in the range 1.1-8.7%, and limits of detection and quantification were 0.007-0.031 ng mg(-1) and 0.012-0.062 ng mg(-1), respectively. The LOQ for THC (0.062 ng mg(-1)) was below the cut-off value (LOQ Toxicologie Analytique (SFTA). The optimized SPME method was applied in analysis of hair samples from Cannabis drug users, showing that CBN and CBD were present in all samples analyzed. 2010 Elsevier B.V. All rights reserved.

  8. Extension of a dynamic headspace multi-volatile method to milliliter injection volumes with full sample evaporation: Application to green tea.

    Science.gov (United States)

    Ochiai, Nobuo; Sasamoto, Kikuo; Tsunokawa, Jun; Hoffmann, Andreas; Okanoya, Kazunori; MacNamara, Kevin

    2015-11-20

    An extension of multi-volatile method (MVM) technology using the combination of a standard dynamic headspace (DHS) configuration, and a modified DHS configuration incorporating an additional vacuum module, was developed for milliliter injection volume of aqueous sample with full sample evaporation. A prior step involved investigation of water management by weighing of the water residue in the adsorbent trap. The extended MVM for 1 mL aqueous sample consists of five different DHS method parameter sets including choice of the replaceable adsorbent trap. An initial two DHS sampling sets at 25°C with the standard DHS configuration using a carbon-based adsorbent trap target very volatile solutes with high vapor pressure (>10 kPa) and volatile solutes with moderate vapor pressure (1-10 kPa). Subsequent three DHS sampling sets at 80°C with the modified DHS configuration using a Tenax TA trap target solutes with low vapor pressure (88%) for 17 test aroma compounds and moderate recoveries (44-71%) for 4 test compounds. The method showed good linearity (r(2)>0.9913) and high sensitivity (limit of detection: 0.1-0.5 ng mL(-1)) even with MS scan mode. The improved sensitivity of the method was demonstrated with analysis of a wide variety of aroma compounds in brewed green tea. Compared to the original 100 μL MVM procedure, this extension to 1 mL MVM allowed detection of nearly twice the number of aroma compounds, including 18 potent aroma compounds from top-note to base-note (e.g. 2,3-butanedione, coumarin, furaneol, guaiacol, cis-3-hexenol, linalool, maltol, methional, 3-methyl butanal, 2,3,5-trimethyl pyrazine, and vanillin). Sensitivity for 23 compounds improved by a factor of 3.4-15 under 1 mL MVM conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Practical Implication of Chromatographic Method for Estimation of Aceclofenac and Pregabalin in Bulk and Pharmaceutical Dosage Forms

    Directory of Open Access Journals (Sweden)

    Hitendrakumar D. Gelani

    2014-01-01

    Full Text Available Background. Aceclofenac and Pregabalin in combination significantly reduce pain as compared to individual drug in chronic low back pain. Literature reveals that all the reported spectrophotometric methods either need tedious extraction procedures, do not offer high sensitivity, use nonspecific reagent, or recommend the measurement of absorbance in the near UV region where interference most probably occurs that does not offer suitable linearity range. Result. A selective, sensitive, accurate, and precise, high performance liquid chromatographic method with UV detector analysis of Aceclofenac and Pregabalin was investigated. Good chromatographic separation was achieved using an ODS-BP hypersil C18 column (250 mm × 4.6 mm, i.d., 5 μm and a mobile phase consisting of 0.05 M phosphate buffer (KH2PO4 (pH 6.0 : methanol (60 : 40, v/v at a flow rate 1 mL/min. The ultraviolet detector was set at wavelength 218 nm. Retention time for Aceclofenac and Pregabalin was found to be 3.220 and 5.910 min, respectively. Rectilinear relationship with good regression coefficients 0.999 and 0.999 was found over the concentration ranges of 5–25 μg/mL and 3.75–18.75 μg/mL for ACF and PGB, respectively, with detection limits 0.64 and 0.35 μg/mL and quantitation limits 1.95 and 1.06 μg/mL. Conclusion. The mean percentage recoveries were in the range of 98.45–100.08 and 99.69–100.48 for ACF and PGB, respectively. The developed method was successfully applied to the analysis of the drugs in their commercial tablets.

  10. The use of chromatographic methods coupled to mass spectrometry for the study of emerging pollutants in the environment.

    Science.gov (United States)

    Carmona, Eric; Picó, Yolanda

    2018-01-25

    The consumption of compounds that improve the human health and wellness is increasing, and as a result, the residues of these substances reach the environment or food chain. For this reason, the scientific community is looking for new analytical methods that are more accurate and can detect the greatest number of compounds in different matrices. This manuscript compares different studies in abiotic and biotic matrices, where most of them (92%) uses Liquid Chromatography to separate the compounds. For the detection, most of the studies for both matrices uses, coupled to the chromatograph, a triple quadrupole mass spectrometer (50%) due to the precision to quantify the concentration of these compounds. Time of Flight (QToF) mass spectrometer is used in 24% of the manuscripts reviewed, in both matrices. It is possible to quantify the concentration of these compounds with the instrument but do not provide as high accuracy as the triple quadrupole.

  11. Development and validation of a fast chromatographic method for screening and quantification of legal and illegal skin whitening agents.

    Science.gov (United States)

    Desmedt, B; Rogiers, V; Courselle, P; De Beer, J O; De Paepe, K; Deconinck, E

    2013-09-01

    During the last years, the EU market is flooded by illegal cosmetics via the Internet and a so-called "black market". Among these, skin-bleaching products represent an important group. They contain, according to the current European cosmetic legislation (Directive 76/768/EEC), a number of illegal active substances including hydroquinone, tretinoin and corticosteroids. These may provoke as well local as systemic toxic effects, being the reason for their banning from the EU market. To control this market there is a need for a fast screening method capable of detecting illegal ingredients in the wide variety of existing bleaching cosmetic formulations. In this paper the development and validation of an ultra high pressure liquid chromatographic (UHPLC) method is described. The proposed method makes use of a Waters Acquity BEH shield RP18 column with a gradient using 25 mM ammonium borate buffer (pH 10) and acetonitrile. This method is not only able to detect the major illegal (hydroquinone, tretinoin and six dermatologic active corticosteroids) and legal whitening agents, the latter having restrictions with respect to concentration and application (kojic acid, arbutin, nicotinamide and salicylic acid), but can also quantify these in a run time of 12 min. The method was successfully validated using the "total error" approach in accordance with the validation requirements of ISO-17025. During the validation a variety of cosmetic matrices including creams, lotions and soaps were taken into consideration. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Accuracy profile validation of a new analytical method for butane measurement using headspace-gas chromatography-mass spectrometry.

    Science.gov (United States)

    Varlet, V; Smith, F; Augsburger, M

    2013-01-15

    The aim of our study was to provide an innovative HS-GC/MS method applicable to the routine determination of butane concentration in forensic toxicology laboratories. The main drawback of the GC/MS methods discussed in literature concerning butane measurement was the absence of a specific butane internal standard necessary to perform quantification. Because no stable isotope of butane is commercially available, it is essential to develop a new approach by an in situ generation of standards. To avoid the manipulation of a stable isotope-labelled gas, we have chosen to generate in situ an internal labelled standard gas (C(4)H(9)D) following the basis of the stoichiometric formation of butane by the reaction of deuterated water (D(2)O) with Grignard reagent butylmagnesium chloride (C(4)H(9)MgCl). This method allows a precise measurement of butane concentration and therefore, a full validation by accuracy profile was presented. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Detection of arecoline by simple high-performance thin-layer chromatographic method in Indian nontobacco pan masala.

    Science.gov (United States)

    Adhikari, Anjan; Hazra, Alok Kumar; Sur, Tapas Kumar

    2015-01-01

    Chewing the habit of blended pan masala containing areca nut with or without tobacco is a common practice in the Indian subcontinent. Arecoline, a pyridine alkaloid presence in areca nut alarmed for oral carcinogenesis and strictly prohibited in the western world. However, in India using blended pan masala is very popular among young and old individuals. In this context, we aimed to detect arecoline in Indian blended nontobacco pan masala sold in Kolkata using a simple densitometric high-performance thin-layer chromatographic (HPTLC) method and for alarming their use in common people. Eleven popularly Indian blended nontobacco pan masala were collected from the territory of Kolkata and isolated arecoline, following solvent extraction method derived for pyridine alkaloid. The quantitative analysis of arecoline was measured using automated software-based HPTLC instruments and validated the method according to International Conference on Harmonization guidelines. Arecoline was detected in all 11 blended nontobacco pan masala samples in a range of minimum 130 to maximum 415 μg/g dry samples. Arecoline is hazardous carcinogenic compound, so the use of Indian blended nontobacco pan masala should be restricted. Further, the method was found suitable for routine quantitative analysis of arecoline in areca nut containing substances.

  14. Application of Analytical Quality by Design concept for bilastine and its degradation impurities determination by hydrophilic interaction liquid chromatographic method.

    Science.gov (United States)

    Terzić, Jelena; Popović, Igor; Stajić, Ana; Tumpa, Anja; Jančić-Stojanović, Biljana

    2016-06-05

    This paper deals with the development of hydrophilic interaction liquid chromatographic (HILIC) method for the analysis of bilastine and its degradation impurities following Analytical Quality by Design approach. It is the first time that the method for bilastine and its impurities is proposed. The main objective was to identify the conditions where an adequate separation in minimal analysis duration could be achieved within a robust region. Critical process parameters which have the most influence on method performance were defined as acetonitrile content in the mobile phase, pH of the aqueous phase and ammonium acetate concentration in the aqueous phase. Box-Behnken design was applied for establishing a relationship between critical process parameters and critical quality attributes. The defined mathematical models and Monte Carlo simulations were used to identify the design space. Fractional factorial design was applied for experimental robustness testing and the method is validated to verify the adequacy of selected optimal conditions: the analytical column Luna(®) HILIC (100mm×4.6mm, 5μm particle size); mobile phase consisted of acetonitrile-aqueous phase (50mM ammonium acetate, pH adjusted to 5.3 with glacial acetic acid) (90.5:9.5, v/v); column temperature 30°C, mobile phase flow rate 1mLmin(-1), wavelength of detection 275nm. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Stability indicating high performance thin layer chromatographic method for quantitation of venlafaxine in bulk and pharmaceutical dosage form

    Directory of Open Access Journals (Sweden)

    Sunil K Dubey

    2015-01-01

    Full Text Available Background: Venlafaxine (VEN is a phenethylamine bicyclic compound, chemically, 1-(2-[dimethyl amino]-1-[4-methoxy phenyl] ethyl cyclo-hexan-1ol hydrochloride. It is a antidepressant. It inhibits the reuptake of serotonin, nor adrenaline and dopamine to a lesser extent at the presynaptic membrane. Aim: A simple, rapid, precise, accurate, and economical high performance thin layer chromatographic (HPTLC method has been developed and validated for the determination of VEN both as a bulk drug and in formulation. Materials and Methods: The method uses aluminum plates precoated with silica gel 60 F254 as the stationary phase and dichloromethane:acetonitrile:N-hexane:triethylamine: 0.5:0.5:4:0.7 (v/v/v/v as mobile phase. Results: This system gave compact spots for VEN (R f = 0.46 ± 0.05. Forced degradation studies were done by subjecting VEN to acid and alkali hydrolysis, oxidation, and reduction. The peak of the degradation product was well resolved from that of the pure drug and had significant different R f values. Analysis of VEN was performed in the absorbance mode at 225 nm. The limit of detection and quantification were 12.48 and 37.81 ng/spot respectively. Conclusions: The developed method was validated and found to be simple, specific, accurate and precise and can be used for routine quality control analysis of VEN in bulk and pharmaceutical formulation.

  16. Validation of a QuEChERS-based gas chromatographic method for analysis of pesticide residues in Cassia angustifolia (senna).

    Science.gov (United States)

    Tripathy, Vandana; Saha, Ajoy; Patel, Dilipkumar J; Basak, B B; Shah, Paresh G; Kumar, Jitendra

    2016-08-02

    A simple multi-residue method based on modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) approach was established for the determination of 17 organochlorine (OC), 15 organophosphorous (OP) and 7 synthetic pyrethroid (SP) pesticides in an economically important medicinal plant of India, Senna (Cassia angustifolia), by gas chromatography coupled to electron capture and flame thermionic detectors (GC/ECD/FTD) and confirmation of residues was done on gas chromatograph coupled with mass spectrometry (GC-MS). The developed method was validated by testing the following parameters: linearity, limit of detection (LOD), limit of quantification (LOQ), matrix effect, accuracy-precision and measurement uncertainty; the validation study clearly demonstrated the suitability of the method for its intended application. All pesticides showed good linearity in the range 0.01-1.0 μg mL(-1) for OCs and OPs and 0.05-2.5 μg mL(-1) for SPs with correlation coefficients higher than 0.98. The method gave good recoveries for most of the pesticides (70-120%) with intra-day and inter-day precision pesticide residues in 12 commercial market samples obtained from different locations in India.

  17. Development of off-line layer chromatographic and total reflection X-ray fluorescence spectrometric methods for arsenic speciation

    Energy Technology Data Exchange (ETDEWEB)

    Mihucz, Victor G. [Joint Research Group of Environmental Chemistry of Hungarian Academy of Sciences and L. Eoetvoes University, P. O. Box 32, H-1518 Budapest (Hungary); Hungarian Satellite Centre of Trace Elements Institute to UNESCO, P. O. Box 32, H-1518 Budapest (Hungary); Moricz, Agnes M. [L. Eoetvoes University, Department of Chemical Technology and Environmental Chemistry, P.O. Box 32, H-1518 Budapest (Hungary); Kroepfl, Krisztina [Joint Research Group of Environmental Chemistry of Hungarian Academy of Sciences and L. Eoetvoes University, P. O. Box 32, H-1518 Budapest (Hungary); Szikora, Szilvia [Joint Research Group of Environmental Chemistry of Hungarian Academy of Sciences and L. Eoetvoes University, P. O. Box 32, H-1518 Budapest (Hungary); Tatar, Eniko [Hungarian Satellite Centre of Trace Elements Institute to UNESCO, P. O. Box 32, H-1518 Budapest (Hungary); L. Eoetvoes University, Department of Inorganic and Analytical Chemistry, P.O. Box 32, H-1518 Budapest (Hungary); Parra, Lue Meru Marco [Universidad Centro-occidental Lisandro Alvarado, Decanato de Agronomia, Departamento de Quimica y Suelos Unidad de Analisis Instrumental, Apartado Postal 4076, Cabudare 3023 (Venezuela); Zaray, Gyula [Joint Research Group of Environmental Chemistry of Hungarian Academy of Sciences and L. Eoetvoes University, P. O. Box 32, H-1518 Budapest (Hungary) and Hungarian Satellite Centre of Trace Elements Institute to UNESCO, P. O. Box 32, H-1518 Budapest (Hungary) and L. Eoetvoes University, Department of Inorganic and Analytical Chemistry, P.O. Box 32, H-1518 Budapest (Hungary)]. E-mail: zaray@ludens.elte.hu

    2006-11-15

    Rapid and low cost off-line thin layer chromatography-total reflection X-ray fluorescence spectrometry and overpressured thin layer chromatography-total reflection X-ray fluorescence spectrometry methods have been developed for separation of 25 ng of each As(III), As(V), monomethyl arsonic acid and dimethylarsinic acid applying a PEI cellulose stationary phase on plastic sheets and a mixture of acetone/acetic acid/water = 2:1:1 (v/v/v) as eluent system. The type of eluent systems, the amounts (25-1000 ng) of As species applied to PEI cellulose plates, injection volume, development distance, and flow rate (in case of overpressured thin layer chromatography) were taken into consideration for the development of the chromatographic separation. Moreover, a microdigestion method employing nitric acid for the As spots containing PEI cellulose scratched from the developed plates divided into segments was developed for the subsequent total reflection X-ray fluorescence spectrometry analysis. The method was applied for analysis of root extracts of cucumber plants grown in As(III) containing modified Hoagland nutrient solution. Both As(III) and As(V) were detected by applying the proposed thin layer chromatography/overpressured thin layer chromatography-total reflection X-ray fluorescence spectrometry methods.

  18. QbD-oriented development and validation of a bioanalytical method for nevirapine with enhanced liquid-liquid extraction and chromatographic separation.

    Science.gov (United States)

    Beg, Sarwar; Chaudhary, Vandna; Sharma, Gajanand; Garg, Babita; Panda, Sagar Suman; Singh, Bhupinder

    2016-06-01

    The present studies describe the systematic quality by design (QbD)-oriented development and validation of a simple, rapid, sensitive and cost-effective reversed-phase HPLC bioanalytical method for nevirapine in rat plasma. Chromatographic separation was carried out on a C18 column using isocratic 68:9:23% v/v elution of methanol, acetonitrile and water (pH 3, adjusted by orthophosphoric acid) at a flow rate of 1.0 mL/min using UV detection at 230 nm. A Box-Behnken design was applied for chromatographic method optimization taking mobile phase ratio, pH and flow rate as the critical method parameters (CMPs) from screening studies. Peak area, retention time, theoretical plates and peak tailing were measured as the critical analytical attributes (CAAs). Further, the bioanalytical liquid-liquid extraction process was optimized using an optimal design by selecting extraction time, centrifugation speed and temperature as the CMPs for percentage recovery of nevirapine as the CAA. The search for an optimum chromatographic solution was conducted through numerical desirability function. Validation studies performed as per the US Food and Drug Administration requirements revealed results within the acceptance limit. In a nutshell, the studies successfully demonstrate the utility of analytical QbD approach for the rational development of a bioanalytical method with enhanced chromatographic separation and recovery of nevirapine in rat plasma. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  19. Improved liquid chromatographic method for determination of organic acids in leaves, pulp, fruits, and rinds of Garcinia.

    Science.gov (United States)

    Jayaprakasha, Guddadarangavvanahally K; Jena, Bhabani S; Sakariah, Kunnumpurath K

    2003-01-01

    An improved liquid chromatographic (LC) method was developed for determination of organic acids in leaves, pulp, fruits, and rinds of Garcinia. At present, the commonly used LC method for analysis of organic acids in Garcinia extracts uses direct application of the extracts on the column. This practice gradually reduces efficiency of the column and shortens its life. In the improved method, the interfering substances such as pigments and xanthones were effectively removed by passing the aqueous extract through an ODS cartridge. With subsequent injection on a C18 reversed-phase column, using 6.0 mM phosphoric acid as the mobile phase with a flow rate of 1.0 mL/min and UV detection at 210 nm, the organic acids were determined in the extracts. The major organic acid was (-)-hydroxycitric acid at the level of 2.5, 0.8, 3.0, and 20.1% in leaf, pulp, fresh fruit, and dried rinds, respectively. Minor quantities of hydroxycitric acid lactone, oxalic acid, and citric acid were also identified. Limits of detection and recoveries were 0.9-1.5 microg and 93.9-99.8%, respectively. This is the first report on the composition of organic acids from Garcinia pedunculata.

  20. Comparison of various extraction methods for policosanol from rice bran wax and establishment of chromatographic fingerprint of policosanol.

    Science.gov (United States)

    Wang, Mei-Fei; Lian, Hong-Zhen; Mao, Li; Zhou, Jing-Ping; Gong, Hui-Juan; Qian, Bao-Yong; Fang, Yan; Li, Jie

    2007-07-11

    A capillary gas chromatographic (GC) method has been developed for the separation and determination of policosanol components extracted from rice bran wax. A Varian CP-sil 8 CB column was employed, and an oven temperature was programmed. Gas chromatography-mass spectrometry (GC-MS) was used to identify the composition of policosanol. Quantitative analysis was carried out by means of hydrogen flame ionization detector (FID) with dinonyl phthalate (DNP) as internal standard. The results indicated that the extract obtained by dry saponification has the highest contents of octacosanol and triacontanol among extracts by all used extraction methods including dry saponification, saponification in alcohol, saponification in water (neutralized and non-neutralized), and transesterification. Meanwhile, the GC-MS fingerprint of policosanol extracted by dry saponification has been established. Euclidean distance similarity calculation showed remarkable consistency of compositions and contents among 12 batches of policosanol from a rice bran wax variety. This protocol provided a rapid and feasible method for quality control of policosanol products.

  1. Rapid gas chromatographic method for the determination of famoxadone, trifloxystrobin and fenhexamid residues in tomato, grape and wine samples.

    Science.gov (United States)

    Likas, D T; Tsiropoulos, N G; Miliadis, G E

    2007-05-25

    Trifloxystrobin, fenhexamid and famoxadone belong to the generation of fungicides acting against a broad spectrum of fungi and widely used in Integrated Pest Management strategies in different agricultural crops but mainly in viticulture. In the present work, a gas chromatographic (GC) method for their determination was developed and validated on tomato, grape and wine matrices. The method was based on a simple one step liquid-liquid microextraction with cyclohexane/dichloromethane (9+1, v/v) and determination of fungicides by gas chromatography with nitrogen phosphorous (NP-) and electron capture (EC-) detection, and ion trap mass spectrometry (ITMS) for confirmation. The method was validated by recovery experiments, assessment of matrix effect and calculation of the associated uncertainty. Recoveries for GC-NPD and GC-ECD were found in the range of 81-102% with RSD trifloxystrobin being the most sensitive. The expanded uncertainty, calculated for a sample concentration of 0.10 mg/kg, ranged from 4.8 to 13% for the GC-ECD and from 5.4 to 29% for the GC-NPD. The concentration levels for famoxadone residues found in tomato and grape samples from field experiments were clearly below the EU established MRL values, thus causing no problems in terms of food safety.

  2. Modified Gas Chromatographic Method to Determine Monoacylglycerol and Diacylglycerol Contents in Edible Fats and Oils.

    Science.gov (United States)

    Satou, Chiemi; Goto, Hirofumi; Yamazaki, Yuya; Saitou, Katsuyoshi; Matsumoto, Shoji; Takahashi, Ou; Miyazaki, Yosuke; Ikuta, Keiichi; Yajima, Yosuke

    2017-06-01

    Monoacylglycerol (MAG) and diacylglycerol (DAG) are minor components of edible fats and oils, and they relate to the quality of these foods. The AOCS official method Cd 11b-91 has been used to determine MAG and DAG contents in fats and oils. There are, however, difficulties in the determination of MAG and DAG using this analytical procedure. Therefore, we improved this method by modifying the trimethylsilyl derivatization procedure and replacing the internal standard (IS) material. In our modified method, TMS-HT (mixture of hexamethyldisilazane and trimethylchlorosilane) was used for derivatization of MAG and DAG, which was followed by liquid-liquid extraction with water and n-hexane solution containing the IS, tricaprin. Using the modified method, we demonstrated superior repeatability in comparison with that of the AOCS method by reducing procedural difficulties. The relative standard deviation of distearin peak areas was 1.8% or 2.9% in the modified method, while it was 5.6% in the AOCS method. In addition, capillary columns, such as DB-1ht and DB-5ht could be used in this method.

  3. Application of a validated stability-indicating chromatographic method to evaluate the reproducibility between batches of small peptides in solution.

    Science.gov (United States)

    Oliva, Alexis; Llabrés, Matías; Fariña, José B

    2010-08-18

    A stability-indicating reversed-phase high-performance liquid chromatographic method was developed and validated as per the International Conference on Harmonization (ICH) guidelines to evaluate the reproducibility of batches of synthetic peptides included in a stability program, in particular cholecystokinin (CCK-4) peptide. Both isothermal and nonisothermal approaches were used to determine stability under experimental conditions and the resulting degradation products were identified by liquid chromatography-mass spectrometry (LC-MS). The principal degradation product was the cyclic dimer, although another two products derived from it were also detected, due to the loss of one or two Phe-NH(2) residues. The dimerization follows first-order kinetics, whereas the hydrolytic cleavage implies both consecutive and in-parallel processes. The linear Arrhenius plot indicates that the degradation mechanism and kinetics do not change with temperature or the batch, but the degradation rate does depend on the batch, for example, the shelf-life at 25 degrees C was 2.54 days for batch 3, which is 13-times lower than batch 2. This variability is caused by a change in the synthesis process introduced by the manufacturer. The combination of these two elements: the analytical and stability-evaluating methods provide enough data to establish a stability-indicating profile, as required by the guideline ICH-Q6B for biotechnological/biological products. Copyright 2010 Elsevier B.V. All rights reserved.

  4. Simple and sensitive high performance liquid chromatographic method for the simultaneous quantitation of the phenylalanine in human plasma

    Directory of Open Access Journals (Sweden)

    Hossein Danafar

    2015-09-01

    Full Text Available Phenylalanine (Phe is the most reliable indicator for the diagnosis of phenylketonuria (PKU. The purpose of this study is to establish a reliable and quick method for the assignment of Phe in peripheral capillary blood from newborns and children by high performance liquid chromatography with ultraviolet detection (HPLC-UV. PKU is an inborn error of metabolism characterized by the inability of the body to use Phe. A rapid and sensitive high performance liquid chromatographic (HPLC method has been developed for determination of Phe in plasma. The method uses a protein precipitation step with sulfosalicilic acid for sample preparation by separation on a Nova-pack C18 column using sodium acetate buffer and acetonitrile (94: 6 v/v adjusted to pH 6.5 with glacial acetic acid. The eluted peaks detected by a UV detector was set at wavelength of 215 nm. The method was validated in the range of Phe concentrations from 0.1 to 20 µg/ml. The limits of detection (LOD and quantitation (LOQ of the method were 0.05 and 0.1 µg/ml, respectively. The average drug recovery from plasma was 88.60 percent throughout the linear concentration range., with the average within-run and between-run accuracy values of 103.3 and 115.350, respectively. The method is quick, easy, very steady and precise for the screen, assignment, and evaluation of Phe in human plasma by HPLC, which is particularly a useful way for screening and diagnosis of PKU and monitoring of a diet therapy.

  5. High performance liquid chromatographic method for determination of ezetimibe in pharmaceutical formulation tablets

    Directory of Open Access Journals (Sweden)

    Hossein Danafar

    2016-09-01

    Full Text Available Ezetimide belongs to a class of lipid lowering    compounds    that    selectively    inhibits intestinal   absorption   of   cholesterol   and   related phytosterols. The purpose of this study is to establish a reliable and quick method for the assignment of ezetimibe in tablets form by high performance liquid chromatography with ultraviolet detection (HPLC-UV. A rapid  and  sensitive  HPLC  method  has  been developed  for  determination  of  ezetimibe in tablets formulation.  Mobile phase was composed of acetonitrile-ammonium acetate (10 mM, pH 3.0, 75:25 (v/v with a flow rate of 1 ml/min. The eluted peaks were detected by a UV detector was set at wavelength of 240 nm. The method results in excellent separation with good resolution of analyte. Standard curves were linear (r = 0.996 over the wide ezetimibe concentration range of 10-60.0 µg mL-1 with acceptable accuracy and precision. The limits of detection (LOD and quantitation (LOQ of the method were 5 and 10 µg/ml, respectively. The average drug recovery was 95.3% throughout the linear concentration range. Statistical  assessment  of  various  in  vitro  dissolution  parameters  and  assay  results was  also  conducted  to  establish  if  there were  any significant difference among them. The validated HPLC method has been used successfully to study ezetimibe. Due to simplicity, rapidity and accuracy of the method, we believe that the method will be useful for routine quality control analysis.

  6. Spectrophotometric and high performance liquid chromatographic methods for sensitive determination of bisphenol A.

    Science.gov (United States)

    Zhuang, Yafeng; Zhou, Meng; Gu, Jia; Li, Xiangmei

    2014-03-25

    A new spectrophotometric method for the determination of trace amounts of bisphenol A based on a diazotization-coupling reaction was developed. In acidic solution, clenbuterol was first diazotized with sodium nitrite, then coupled with bisphenol A to from an azo-compound [I] in NH3-NH4Cl buffer, which shows a maximum absorption at 410 nm. The effects of the amount of sodium nitrite, diazo reaction time, the amount of clenbuterol, coupling reaction time and coupling reaction temperature have been examined. Under the optional conditions, the determination of the linear range of bisphenol A is 0.24-8.4 μg/mL, correlation coefficient is 0.9905 and detection limit of this method is 0.15 μg/mL. The spectrophotometric method is simple, rapid, high sensitivity with better accuracy. High performance liquid chromatography (HPLC) technique combined with this new spectrophotometric method has been also developed for the measurement of bisphenol A. The analysis was achieved on a C18 column using water and methanol as a mobile phase and the detection was done spectrophotometrically at 410 nm. These reported methods were applied to the determination of bisphenol A in hot water in contact with commercially available table-water bottle samples. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Chromatographic method for determination of the free amino acid content of chamomile flowers.

    Science.gov (United States)

    Ma, Xiaoli; Zhao, Dongsheng; Li, Xinxia; Meng, Lei

    2015-01-01

    To determine the free amino acid contents of chamomile flowers using reverse-phase high-performance column chromatography preceded by pre-column derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC), and to determine the reliability of this method. Derivatization with reconstituted AQC was used to prepare the samples and standards for injection into the chromatography column. The peaks were analyzed by fluorescence detection (λ excitation, 250 nm; λ emission, 395 nm. Alanine, proline, and leucine were the most abundant amino acids, whereas tyrosine and methionine were the least abundant. The linearity of the method was found to be good with amino acid concentrations of 0.012-0.36 μM. The precision was 0.05-1.36%; average recovery, 91.12-129.41%; and limit of detection, 0.006-0.058 μM. The method is reliable for determining the free amino acid content of different types of chamomile flowers.

  8. A fast and accurate numerical method for solving simulated moving bed (SMB) chromatographic separation problems

    DEFF Research Database (Denmark)

    Lim, Young-il; Jørgensen, Sten Bay

    2003-01-01

    numerical solutions are obtained. Stable solutions are guaranteed if the Courant-Friedrichs-Lewy (CFL) condition is satisfied. The boundary condition and recycle flow treatments are much simpler than for the time integrator in the framework of the method of lines. Applying the CE/SE method for SMB......Solving simulated moving bed (SMB) chromatography models requires fast and accurate numerical techniques, since their system size computed is large due to multi-columns and multi-components, in addition the axial solution profiles contain steep moving fronts. The space-time conservation element....../solution element (CE/SE) method addressed in this study enforces both local and global flux conservation in space and time, and uses a simple stencil structure (two points at the previous time level and one point at the present time level) on staggered space-time grids. Thus, accurate and computationally efficient...

  9. Development and Assessment of a Gas Chromatographic Based Method for the Quantification of Thymol from Cream Based Formulation.

    Science.gov (United States)

    Samani, Soliman Mohammadi; Moein, Mahmoodreza; Petramfar, Peyman; Zarshenas, Mohammad M

    2016-01-01

    Herbal medicines have been used for different illnesses. However, standardization of these medicaments should be done before introducing for treatment purposes. Ajwain an essential oil, is traditionally used for neuropathic pain. To develop and assess a gas chromatographic-based method for the quantification of thymol in Ajwain essential oil, current work was performed. Both pure thymol and Ajwain creams were prepared and subjected to hydrodistillation method under temperature-controlled procedure to re-extract the applied essential oil and pure thymol. Previously, Ajwain seeds essential oil composition was analyzed and identified using GC/MS. After re-extraction, GC/FID was applied quantitatively to determine the thymol content in the Ajwain and thymol creams. The parameters represented in International Conference on Harmonization (ICH) guidelines were considered for the determination. Thymol content in a 50 g laminated tube of Ajwain cream was calculated as 2.34 g ± 0.02. Regarding the total thymol content of a 50 g laminated tube of Thymol cream (2.43 g), recovery percent for Ajwain cream was calculated as 96.29 %. Using hydrodistillation for an essential oil- containing cream sample via Clevenger proved to be a simple and convenient method to work up and extract active volatile components of such semisolid formulation. However, the extraction yield was profoundly related to the condenser temperature. The current employed determination method is introduced as a rapid and reliable method and thus, can be suggested for the quality control assessment of phytopharmaceutical semisolid preparations containing thymol and similar volatile constituents.

  10. Rigorous evaluation of chemical measurement uncertainty: liquid chromatographic analysis methods using detector response factor calibration

    Science.gov (United States)

    Toman, Blaza; Nelson, Michael A.; Bedner, Mary

    2017-06-01

    Chemical measurement methods are designed to promote accurate knowledge of a measurand or system. As such, these methods often allow elicitation of latent sources of variability and correlation in experimental data. They typically implement measurement equations that support quantification of effects associated with calibration standards and other known or observed parametric variables. Additionally, multiple samples and calibrants are usually analyzed to assess accuracy of the measurement procedure and repeatability by the analyst. Thus, a realistic assessment of uncertainty for most chemical measurement methods is not purely bottom-up (based on the measurement equation) or top-down (based on the experimental design), but inherently contains elements of both. Confidence in results must be rigorously evaluated for the sources of variability in all of the bottom-up and top-down elements. This type of analysis presents unique challenges due to various statistical correlations among the outputs of measurement equations. One approach is to use a Bayesian hierarchical (BH) model which is intrinsically rigorous, thus making it a straightforward method for use with complex experimental designs, particularly when correlations among data are numerous and difficult to elucidate or explicitly quantify. In simpler cases, careful analysis using GUM Supplement 1 (MC) methods augmented with random effects meta analysis yields similar results to a full BH model analysis. In this article we describe both approaches to rigorous uncertainty evaluation using as examples measurements of 25-hydroxyvitamin D3 in solution reference materials via liquid chromatography with UV absorbance detection (LC-UV) and liquid chromatography mass spectrometric detection using isotope dilution (LC-IDMS).

  11. Rigorous evaluation of chemical measurement uncertainty: Liquid chromatographic analysis methods using detector response factor calibration.

    Science.gov (United States)

    Toman, Blaza; Nelson, Michael A; Bedner, Mary

    2017-06-01

    Chemical measurement methods are designed to promote accurate knowledge of a measurand or system. As such, these methods often allow elicitation of latent sources of variability and correlation in experimental data. They typically implement measurement equations that support quantification of effects associated with calibration standards and other known or observed parametric variables. Additionally, multiple samples and calibrants are usually analyzed to assess accuracy of the measurement procedure and repeatability by the analyst. Thus, a realistic assessment of uncertainty for most chemical measurement methods is not purely bottom-up (based on the measurement equation) or top-down (based on the experimental design), but inherently contains elements of both. Confidence in results must be rigorously evaluated for the sources of variability in all of the bottom-up and top-down elements. This type of analysis presents unique challenges due to various statistical correlations among the outputs of measurement equations. One approach is to use a Bayesian hierarchical (BH) model which is intrinsically rigorous, thus making it a straightforward method for use with complex experimental designs, particularly when correlations among data are numerous and difficult to elucidate or explicitly quantify. In simpler cases, careful analysis using GUM Supplement 1 (MC) methods augmented with random effects meta analysis yields similar results to a full BH model analysis. In this article we describe both approaches to rigorous uncertainty evaluation using as examples measurements of 25-hydroxyvitamin D3 in solution reference materials via liquid chromatography with UV absorbance detection (LC-UV) and liquid chromatography mass spectrometric detection using isotope dilution (LC-IDMS).

  12. Rapid, sensitive liquid chromatographic method for determination of zearalenone and alpha- and beta-zearalenol in wheat.

    Science.gov (United States)

    Trenholm, H L; Warner, R M; Fitzpatrick, D W

    1984-01-01

    A rapid, sensitive liquid chromatographic (LC) method is described for quantitative determination of zearalenone and alpha- and beta-zearalenol in wheat. The procedure incorporates an internal standard, zearalenone oxime, to facilitate quantitation and automated analysis. A sample, buffered with pH 7.8 phosphate, is extracted with water-ethanol-chloroform (2 + 50 + 75) and cleaned up. The final residue is dissolved in LC mobile phase and injected onto a reverse phase RP-18 column under the following conditions: water-methanol-acetonitrile (5 + 3 + 2) mobile phase; fluorescence (excitation wavelength 236 nm, 418 nm cut-off emission filter) and UV (254 nm, range 0.0025 AU) detectors. The limit of detectability (twice background) is 0.5 ng for zearalenone and alpha-zearalenol standards on the fluorescence detector and 4 ng for beta-zearalenol on the UV detector, which is equivalent to 20 micrograms zearalenone and 20 micrograms alpha-zearalenol/kg, and 160 micrograms beta-zearalenol/kg feed. Standard curves are linear over the range 0-35 ng zearalenone and alpha-zearalenol on the fluorescence detector and 0-50 ng beta-zearalenol on the UV detector. Recoveries of all compounds are 87.5-101% in the range 0.1-3.0 mg/kg (ppm).

  13. Gas chromatographic flow method for the preconcentration and simultaneous determination of antioxidant and preservative additives in fatty foods.

    Science.gov (United States)

    González, M; Gallego, M; Valcárcel, M

    1999-07-02

    A partially automated gas chromatographic method for the simultaneous determination of antioxidants (tert.-butyl-4-hydroxyanisole, 2,6-di-tert.-butyl-p-hydroxytoluene, tert.-butylhydroquinone, alpha-tocopherol and alpha-tocopheryl acetate) and preservatives (sorbic acid, benzoic acid and their esters) in fatty foods without derivatization is reported. About 95% of triglycerides from lipid material are avoided by manually extracting the samples with a mixture of solvents and the remaining by using a continuous solid-phase extraction system. By using aqueous sample solutions (in 0.1 M HNO3), XAD-2 sorbent and selective elution with 200 microliters of 2-propanol, only ca. 0.03% of total triglycerides present in the original sample remains in the final extract. Manual injection of the extract into a GC-flame ionization detection allows the additives to be determine at concentrations in the range 0.5-100 micrograms/ml with a high precision (ca. 3%). Mass spectrometry in the conventional electron impact mode, in conjunction with library search, permits the unequivocal identification of all the additives. Margarine, oil, cheese, pâté and sauce samples were analysed in this way, all with good results.

  14. Estimation of pioglitazone hydrochloride and metformin hydrochloride in tablets by derivative spectrophotometry and liquid chromatographic methods.

    Science.gov (United States)

    Shankar, Madhira B; Modi, Vaibhav D; Shah, Dimal A; Bhatt, Kashyap K; Mehta, Rajendra S; Geetha, Madhira; Patel, Binita J

    2005-01-01

    Two simple and accurate methods of analysis to determine pioglitazone hydrochloride (PIO) and mefformin hydrochloride (MET) in combined dosage forms were developed using second-derivative spectrophotometry and reversed-phase liquid chromatography (LC). PIO and MET in combined preparations (tablets) were quantified using the second-derivative responses at 227.55 nm for PIO and 257.25 nm for MET in spectra of their solutions in a mixture of methanol and acetonitrile (30 + 70). The calibration curves were linear [correlation coefficient (r) = 0.9984 for PIO and 0.9986 for MET] in the concentration range of 8-40 microg/mL for PIO and 4-12 microg/mL for MET. In the LC method, analysis was performed on a Hypersil ODS-C18 column with 5 microm particle size using the mobile phase acetonitrile-water-acetic acid (75 + 25 + 0.3), adjusted to pH 5.5 with liquor ammonia, at a flow rate of 0.5 mL/min. Measurement was made at a wavelength of 230 nm. Both the drugs were well resolved on the stationary phase, and the retention times were 8.5 min for PIO and 16.0 min for MET. The calibration curves were linear (r = 0.9933 for PIO and 0.9958 for MET) in the concentration range of 4-20 microg/mL for PIO and MET. Both methods were validated, and the results were compared statistically. They were found to be accurate, precise, and specific. The methods were successfully applied to the estimation of PIO and MET in combined tablet formulations.

  15. Study of organosulfurous compounds of oils by chromatographic method with help of flame-photometric detector

    Energy Technology Data Exchange (ETDEWEB)

    Yershov, V.A.; Nosova, V.S.; Shakirova, A.Kh.; Zhil' tsov, N.I.

    1979-01-01

    The possibility is indicated of determining in the gasoline fractions of oils of organosulfuric compounds by the method of gas-liquid chromatography with flame-photometric detector without their preliminary isolation. It was found that the organosulfuric compounds in gasoline fractions of the studied oils of West Siberia are missing and appear in petroleum products in the boiling point interval of 230-250/sup 0/C.

  16. Identification and quantification of adulteration in Garcinia cambogia commercial products by chromatographic and spectrometric methods.

    Science.gov (United States)

    Jamila, Nargis; Choi, Ji Yeon; Hong, Joon Ho; Nho, Eun Yeong; Khan, Naeem; Jo, Cheon Ho; Chun, Hyang Sook; Kim, Kyong Su

    2016-12-01

    Species of genus Garcinia are rich sources of bioactive constituents with antimicrobial, anticancer, anti-inflammatory, hepatoprotective and anti-HIV activities. Commercial products of Garcinia cambogia are used as anti-obesity drugs with increasing market demand. Because of the high price of its products, it can be adulterated with similar lower-priced species. This study was designed to develop and validate an accurate and efficient method for the detection of any adulteration (G. indica) in G. cambogia products. For this purpose, high performance liquid chromatography (HPLC) was used to analyse the ethanolic fruit rind extracts of G. cambogia and G. indica, their formulations of 0.5, 1, 2, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90 and 95% G. indica with G. cambogia, and 11 G. cambogia commercial products. The analytical methods were validated by quality assurance parameters of linearity, sensitivity, precision and accuracy. Two marker peaks were detected in G. indica fruit extract, whereas G. cambogia did not show these peaks. The detected peaks were identified as anthocyanins; cyanidin-3-O-sambubioside and cyanidin-3-O-glucoside. In the study to determine the effect of pH and temperature on the stability of its anthocyanin content, HPLC analysis of G. indica extract showed the highest content at pH 1 and 50°C. Using two different mobile phases, the limits of detection (LOD) for cyanidin-3-O-sambubioside and cyanidin-3-O-glucoside were 0.036 and 0.059, and 0.022 and 0.033 mg kg-1, respectively. Furthermore, the inter-day precision (analytical method fulfils the required criteria of Association of Official Analytical Chemists (AOAC). From this study, it was found that the HPLC method used for the detection of adulteration in G. cambogia products is rapid and accurate.

  17. Validation of high-performance liquid chromatographic method for analysis of fluconazole in microemulsions and liquid crystals

    Directory of Open Access Journals (Sweden)

    Hilris Rocha e Silva

    2014-04-01

    Full Text Available In recent decades, there has been a significant increase in the incidence of fungal diseases. Certain fungal diseases cause cutaneous lesions and in the usual treatment, generally administred orally, the drug reaches the site of action with difficulty and its concentration is too low. An approach much explored in recent years is the development of nanotechnology-based drug delivery systems, and microemulsions (ME and liquid crystals (LC are promising. ME and LC were developed with oleic acid or copaiba oil as the oil phase, propoxyl (5OP ethoxyl (20 OE cetyl alcohol as surfactant and water. An analytical method to assess the incorporation of fluconazole (FLU in the systems under study was validated according to guidelines of the International Conference on Harmonization (ICH guidelines and the Brazilian Food, Drug and Sanitation Agency (ANVISA. The method was conducted on a C18-RP column (250 × 4.6 mm i.d., maintained at room temperature. The mobile phase consisted of acetonitrile and water (50:50, v/v, run at a flow rate of 1.0mL/min and using ultraviolet detection at 210nm. The chromatographic separation was obtained with a retention time of 6.3min, and was linear in the range of 20-400 µg/mL (r2=0.9999. The specificity showed no interference of the excipients. The accuracy was 100.76%. The limits of detection and quantitation were 0.057 and 0.172 µg.mL-1, respectively. Moreover, method validation demonstrated satisfactory results for precision and robustness. The proposed method was applied for the analysis of the incorporation of FLU in ME and LC, contributing to improve the quality control and to assure the therapeutic efficacy.

  18. A non-chromatographic method for the removal of endotoxins from bacteriophages.

    Science.gov (United States)

    Branston, Steven D; Wright, Jason; Keshavarz-Moore, Eli

    2015-08-01

    The Ff filamentous bacteriophages show potential as a new class of therapeutics, displaying utility in materials science as well as pharmaceutical applications. These phages are produced by the infection of E. coli, a Gram-negative bacterium which unavoidably sheds endotoxins into the extracellular space during growth. Since endotoxin molecules are highly immunoreactive, separation from the phage product is of critical importance, particularly those developed for human therapeutic use. The properties of M13, one of the Ff group, present a purification challenge chiefly because the standard scalable method for endotoxin removal from proteins-anion exchange chromatography-is not applicable due to pI similarity between the particles. This article examines the potential of polyethylene glycol (PEG)-NaCl precipitation as a scalable method for the separation of endotoxins from phage M13. Precipitation of M13 by 2% (w/v) PEG 6 000, 500 mM NaCl reduced endotoxin contamination of the phage product by 88%, but additional precipitation rounds did not maintain this proportional decrease. Dynamic light scattering was subsequently used to determine the effectiveness of a detergent to disassociate endotoxin molecules from M13. As a result, PEG-NaCl precipitation was supplemented with up to 2% (v/v) Triton X-100 to improve separation. A 5.7 log10 reduction in endotoxin concentration was achieved over three rounds of precipitation whilst retaining over 97% of the phage. This method compares favorably with the well-known ATPS (Triton X-114) technique for endotoxin removal from protein solutions. © 2015 Wiley Periodicals, Inc.

  19. Pharmacokinetic-pharmacodynamic correlation of imipenem in pediatric burn patients using a bioanalytical liquid chromatographic method

    Directory of Open Access Journals (Sweden)

    Silvia Regina Cavani Jorge Santos

    2015-06-01

    Full Text Available A bioanalytical method was developed and applied to quantify the free imipenem concentrations for pharmacokinetics and PK/PD correlation studies of the dose adjustments required to maintain antimicrobial effectiveness in pediatric burn patients. A reverse-phase Supelcosil LC18 column (250 x 4.6 mm 5 micra, binary mobile phase consisting of 0.01 M, pH 7.0 phosphate buffer and acetonitrile (99:1, v/v, flow rate of 0.8 mL/min, was applied. The method showed good absolute recovery (above 90%, good linearity (0.25-100.0 µg/mL, r2=0.999, good sensitivity (LLOQ: 0.25 µg/mL; LLOD: 0.12 µg/mL and acceptable stability. Inter/intraday precision values were 7.3/5.9%, and mean accuracy was 92.9%. A bioanalytical method was applied to quantify free drug concentrations in children with burns. Six pediatric burn patients (median 7.0 years old, 27.5 kg, normal renal function, and 33% total burn surface area were prospectively investigated; inhalation injuries were present in 4/6 (67% of the patients. Plasma monitoring and PK assessments were performed using a serial blood sample collection for each set, totaling 10 sets. The PK/PD target attained (40%T>MIC for each minimum inhibitory concentration (MIC: 0.5, 1.0, 2.0, 4.0 mg/L occurred at a percentage higher than 80% of the sets investigated and 100% after dose adjustment. In conclusion, the purification of plasma samples using an ultrafiltration technique followed by quantification of imipenem plasma measurements using the LC method is quite simple, useful, and requires small volumes for blood sampling. In addition, a small amount of plasma (0.25 mL is needed to guarantee drug effectiveness in pediatric burn patients. There is also a low risk of neurotoxicity, which is important because pharmacokinetics are unpredictable in these critical patients with severe hospital infection. Finally, the PK/PD target was attained for imipenem in the control of sepsis in pediatric patients with burns.

  20. The application of HP-GFC chromatographic method for the analysis of oligosaccharides in bioactive complexes

    Directory of Open Access Journals (Sweden)

    Savić Ivan

    2009-01-01

    Full Text Available The aim of this work was to optimize a GFC method for the analysis of bioactive metal (Cu, Co and Fe complexes with olygosaccharides (dextran and pullulan. Bioactive metal complexes with olygosaccharides were synthesized by original procedure. GFC was used to study the molecular weight distribution, polymerization degree of oligosaccharides and bioactive metal complexes. The metal bounding in complexes depends on the ligand polymerization degree and the presence of OH groups in coordinative sphere of the central metal ion. The interaction between oligosaccharide and metal ions are very important in veterinary medicine, agriculture, pharmacy and medicine.

  1. Determination of volatile organic compounds in eucalyptus fast pyrolysis bio-oil by full evaporation headspace gas chromatography.

    Science.gov (United States)

    Kosinski Lima, Nathalya; Romualdo Lopes, André; Gimenes Guerrero, Palimecio; Itsuo Yamamoto, Carlos; Augusto Hansel, Fabricio

    2018-01-01

    This paper reports a full evaporation (FE) headspace gas chromatographic (HS-GC) method for the determination of the volatile organic compounds (VOCs) in bio-oil (i.e. methanol, ethanol, acetone, acetic acid and furfural). The method uses a 4μL sample of bio-oil in a headspace vial (ca. 20mL). Complete evaporation of the compounds was achieved after seven minutes at 90°C. The method showed good precision and accuracy for methanol, ethanol, acetone and acetic acid. The recovery of furfural was low (74.3%). The results showed that the protocol can be applied for the determination of methanol, ethanol, acetone and acetic acid in bio-oil. Detection limits ranged from 0.13 to 0.16μg. Acetic acid was the dominant analyte in the heavy bio-oil and light bio-oil analysis (113. 3 and 85.1µgmg(-1), respectively), followed by methanol, ethanol, and acetone. The polymerisation of furfural was suspected as the cause of its poor quantification. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Liquid Chromatographic Method for the Analysis of Brimonidine in Ophthalmic Formulations

    Directory of Open Access Journals (Sweden)

    A. Narendra

    2012-01-01

    Full Text Available A reverse phase LC method was developed for the determination of Brimonidine in eye drops. Chromatography was carried on an Inertsil ODS 3V column (C18 using a mixture of Octane 1- sulfonic acid sodium salt (0.02M (pH 3.5 ± 0.05 and acetonitrile (64:36 v/v as mobile phase at a flow rate of 1 mL/min with UV detection at 254 nm. The drug was eluted at 4.636 min. The detector response was linear in the concentration range of 0.4–72 μg/mL. The limit of detection and limit of quantification were found to be 0.0561 and 0.1848 μg/mL respectively. The proposed method was validated as per the ICH guidelines and can be applied for the routine analysis of Brimonidine in eye drops.

  3. Chromatographic method for diaminopimelic acid detection in calcareous rocks. Presence of a bacterial biomarker in stromatolites.

    Science.gov (United States)

    Borruat, G; Roten, C A; Marchant, R; Fay, L B; Karamata, D

    2001-07-13

    The presence in the environment of diaminopimelic acid (DAP), a specific eubacterial marker, can be attributed to that of bacteria. We report a reliable and highly sensitive method for the quantification of DAP in calcareous rocks. It consists of acid hydrolysis of rock powder, purification of DAP by chromatography on Dowex 50W and Spherogel AA-NA+ columns, and quantitative analysis by high-performance liquid chromatography. Addition of tritiated DAP, the internal standard, allows one to follow the relevant fractions throughout the purification procedure and to determine their yield. The analytical step consists in pre-column derivatization with ortho-phthaldialdehyde of purified samples, and separation through a reversed-phase C18 column. Chemical controls, i.e., oxidation of samples to rule out the presence of co-eluting lanthionine and cystathionine, as well as mass spectrometry, confirm the presence of DAP in analyzed samples. Our method allows the separation of meso- from L- and/or D-stereoisomers of DAP, and reveals their presence in the examined rocks, two stromatolites of different age and geographic origin.

  4. Aqueous size-exclusion chromatographic method for the quantification of cyanobacterial native glycogen.

    Science.gov (United States)

    Izumi, Yoshihiro; Aikawa, Shimpei; Matsuda, Fumio; Hasunuma, Tomohisa; Kondo, Akihiko

    2013-07-01

    Cyanobacterial glycogen has gained interest as a valuable biomass feedstock for biofuel production. However, an ideal method for native glycogen quantification has not been developed. Here, we have proposed a simple methodology that enables the quantitative determination of cyanobacterial glycogen concentration with high repeatability using aqueous size-exclusion chromatography with a differential refractive index detector (SEC/RID). Our SEC/RID system also allows size distributions for native glycogen based on hydrodynamic volumes (Vh), which is proportional to the product of the molecular mass (M) and intrinsic viscosity [η], obtained by universal calibration using linear homopolymers of known M with Mark-Houwink-Sakurada parameters. The universal calibration curve achieved a broad linear range (Vh parameter [η]M=2×10(2)-8×10(8)mLg(-1)) with a high correlation coefficient (R(2)=0.9942), because the developed system is equipped with an OHpak SB-806M HQ aqueous column containing four types of polyhydroxy methacrylate-based particles with different particle and pore sizes. Based on the SEC/RID system, response of molecular size distribution of glycogen in microalgae to the cultivation condition was first observed. Our established SEC/RID method has several advantages over conventional techniques, including the simultaneous quantitative and size distribution analyses of glycogen, and represents a potentially useful tool to elucidate the relationship between structural properties and the roles of glycogen in metabolism. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Evaluation of gas chromatographic methods for the determination of trans fat.

    Science.gov (United States)

    Delmonte, Pierluigi; Rader, Jeanne I

    2007-09-01

    Consumption of trans fat has been associated with increased risk of coronary heart disease. For nutrition labeling purposes, the US Food and Drug Administration (FDA) defines trans fat as the sum of all the fatty acids with at least one nonconjugated double bond in the trans configuration. The FDA regulation states that label declarations of trans fat are not required for products that contain less than 0.5 g of trans fat per serving if no claims are made about fat, fatty acids or cholesterol. While attenuated total reflection Fourier-transformed infrared spectroscopy (ATR-FT-IR) provides reproducible measurements for samples containing more than 5% trans fat, methods based on gas chromatography (GC) are needed to measure lower trans fat levels. Trans fat quantitation by GC has recently been updated by considering more fatty acids, focusing more attention on fatty acids present in low amounts, and by using 100-m high-polarity capillary columns for optimal separation. The consistently high interlaboratory relative standard deviations (RSD, e.g., 21% at 1% trans fatty acids (TFA), 60% at 0.17% TFA), and intralaboratory RSD values (e.g., 10% at 1% TFA, 16% at 0.17% TFA) for trans fat at 1% or less of total fat reported in the collaborative study data for American Oil Chemists Society Official Method Ce 1h-05 suggest the need to carefully define the parameters associated with GC analysis of fatty acids.

  6. An atmospheric pressure chemical ionisation liquid chromatographic-tandem mass spectrometry method for the analysis of benzodiazepines in urine.

    Science.gov (United States)

    Dunlop, S; Hayes, K; Leavy, P; Cusack, D; Maguire, R

    2017-10-01

    The objective of this work was to establish an analytical method for the analysis of 7 Benzodiazepines (diazepam, oxazepam, temazepam, nordiazepam, desalkylflurazepam, alprazolam and α-hydroxyalprazolam) in urine specimens taken from drivers suspected of driving under the influence of drugs. The specimen, calibrator and control preparation involved hydrolysis of conjugated benzodiazepines using β-glucuronidase in sodium acetate buffer, with incubation at 60°C for 2h. Specimens were then centrifuged, before being diluted 1 in 5 (total dilution 1 in 10), with 10% acetonitrile in water. Specimens were analysed using a Shimadzu Prominence UPLC coupled to an AB Sciex 4000 QTrap LC-MS-MS. The chromatographic column was a Shim-pack XR ODS 2.2μm. 3.0×50mm column and the mobile phase was a binary gradient system comprising of mobile phase A which was an ammonium formate/formic acid buffer dissolved in water and mobile phase B which was an ammonium formate/formic acid buffer dissolved in Acetonitrile. APCI was selected as the ionisation technique and the MS was operated in MRM mode, monitoring 2 transitions per analyte. The validation of the method is described. The method was found to be linear, accurate and precise (within day and between day) for diazepam, oxazepam, temazepam, nordiazepam, desalkylflurazepam, alprazolam and α-hydroxyalprazolam. The results of 480 cases are reviewed and show that alprazolam use was found in 35% of cases. Use of benzodiazepines resulting in oxazepam, nordiazepam or temazepam were found ca. 70% of cases analysed. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Stability Indicating Liquid Chromatographic Method for Estimation of Trihexyphenidyl Hydrochloride and Risperidone in Tablet Formulation: Development and Validation Consideration

    Directory of Open Access Journals (Sweden)

    Patel Bhaumik

    2014-01-01

    Full Text Available This paper describes validated reverse phase high-performance liquid chromatographic (RP-HPLC method for simultaneous estimation of trihexyphenidyl hydrochloride (THP and risperidone (RSP in the pure powder form and in combined tablet dosage form. The HPLC separation was achieved on a core shell C18 (100 mm length × 4.6 mm, 2.6 μm particle size using methanol : ammonium acetate buffer 1% (85 : 15 v/v; pH-6.5 as mobile phase and delivered at flow rate of 0.8 mL/min. The calibration plot showed good linear relationship with r2 = 0.997 ± 0.001 for THP and r2 = 0.998 ± 0.001 for RSP in concentration range of 50–175 μg/mL and 50–175 μg/mL, respectively. LOD and LOQ were found to be 0.40 and 1.29 μg/mL for THP and 1.24 and 3.92 μg/mL for RSP. Assay of THP and RSP was found to be 100.16 ± 0.03% and 99.83 ± 0.02%, respectively. THP and RSP were subjected to different stress conditions (acidic, basic, oxidative, thermal, and photolytic degradation. The degraded product peaks were well resolved from the pure drug peak. The method was successfully validated as per the ICH guidelines. The developed RP-HPLC method was successfully applied for the estimation of THP and RSP in tablet dosage form.

  8. An ecofriendly green liquid chromatographic method for simultaneous determination of nicotinamide and clindamycin phosphate in pharmaceutical gel for acne treatment

    Directory of Open Access Journals (Sweden)

    Fawzia Ibrahim

    2017-07-01

    Full Text Available A new green micellar liquid chromatographic method was developed and validated for the quantitative estimation of nicotinamide (NICO and clindamycin phosphate (CLD in bulk and pharmaceutical gel formulation. The analytes are well resolved in less than 6.0 minutes using micellar mobile phase consisting of 0.10M sodium dodecyl sulfate (SDS, 0.3% triethylamine, and 10% 2-propanol in 0.02M orthophosphoric acid at pH 3.0, running through an Eclipse XDB-C8 column (150 mm×4.6 mm, 5 μm particle size with flow rate 1.0 mL/min. The effluent was monitored with diode array detection at 210 nm. The retention times of NICO and CLD were 3.8 minutes and 5.6 minutes, respectively. The method was validated according to the International Conference on Harmonisation (ICH guidelines in terms of linearity, limit of detection, limit of quantification, accuracy, precision, robustness, and specificity to prove its reliability. Linear correlation was achieved by plotting the peak area of each drug against its concentration. It was found to be rectilinear in the ranges of 1.0–40.0 μg/mL and 0.5–15.0 μg/mL with limits of detection of 0.06 μg/mL and 0.03 μg/mL and limits of quantification of 0.19 μg/mL and 0.09 μg/mL for NICO and CLD, respectively. The method was successfully implemented for the simultaneous determination of the analytes in their bulk powder and combined gel formulation with high % recoveries. The ease of sample treatment facilitates and greatly expedites the treatment with reduced cost and improved accuracy of the procedure.

  9. IUPAC gas chromatographic method for determination of fatty acid composition: collaborative study.

    Science.gov (United States)

    Firestone, D; Horwitz, W

    1979-07-01

    An international collaborative study of IUPAC methods II.D.19 and II.D.25 for preparation and GLC analysis of fatty acid methyl esters was begun in 1976. The IUPAC methodology, applicable to animal and vegetable oils and fats and fatty acids from all sources, contains special instructions for preparation and analysis of methyl esters of fatty acids containing 4 or more carbon atoms (analysis of milk fat). Twenty-three collaborators participated in the analysis of 5 known mixtures, 4 vegetable oils, 1 fish oil, and 2 butterfats. Several blind duplicate samples were included. The experimental data were subjected to statistical analysis to examine intra- and interlaboratory variation. Reproducibility and accuracy data for the higher fatty acid (14:0-22:1) mixtures and fish and vegetable oils were satisfactory and were in good agreement with results from an AOCS Smalley Committee check sample program involving analysis of the same samples. Typical coefficients of variation (%) at various concentrations were 15 (2% level), 8.5 (5% level), 7 (10% level), and 3 (50% level). Low recoveries and poor reproducibility were characteristics of results obtained for butyric acid in the butterfat and related known mixtures. A coefficient of variation of about 19% was found for analysis of butyric acid in butterfat, vs coefficients of variation in the range of 4-13% for similar levels of other components in butterfat and other samples. The IUPAC methodology for GLC analysis of fats and oils other than milk fats has been adopted by the AOAC as official first action to replace the current GLC method, 28.063-28.067.

  10. Gas Chromatographic Method for the Analysis of Organic Acids in the Bio-Catalytic Conversion Process.

    Science.gov (United States)

    Kim, Byoung-Hyoun; Cho, Hye Sung

    2015-07-01

    An analytical method for the quantification of acrylic acid (AA), 1,3-propanediol (1,3-PD) and 3-hydroxypropionic acid (3-HP) in the bio-catalytic conversion process has been developed by gas chromatography. A simple liquid-liquid extraction (LLE) procedure was used in the sample preparation. Organic acid additives such as trifluoroacetic acid were used to improve the extraction efficiency in the LLE procedure. Under optimum analysis conditions, all analytes were satisfactorily separated with no interference. In standard calibration, all correlation coefficients (r(2)) were better than or equal to 0.994. In culture media, the intra-batch precision (% relative standard deviation) and recovery (%) as the average value of the quality control samples were 2.3 and 102.4%, respectively. In addition, the inter-batch precision and recovery as the average value of the quality control samples were 5.0 and 104.0%, respectively. In phosphate buffer, the intra-batch precision and recovery as the average value of the quality control samples were 2.7 and 101.6%, respectively. In addition, the inter-batch precision and recovery as the average value of the quality control samples were 2.9 and 101.7%, respectively. The limit of detection (S/N ratio: 3) and limit of quantification (S/N ratio: 10) were 1.0 and 3.5 µg/mL, 3.0 and 10.0 µg/mL, and 9.0 and 30.0 µg/mL, respectively, for AA, 1,3-PD and 3-HP. Consequently, this method was demonstrated to be acceptable for the quantitative analysis of AA, 1,3-PD and 3-HP in culture media and phosphate buffer. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Liquid chromatographic method for the quantification of zearalenone in baby food and animal feed: interlaboratory study.

    Science.gov (United States)

    Arranz, Isabel; Mischke, Carsten; Stroka, Joerg; Sizoo, Eric; van Egmond, Hans; Neugebauer, Michael

    2007-01-01

    An interlaboratory trial for determination of zearalenone (ZON) in baby food and animal feed was conducted. The study involved 39 participants in 16 European Union member states, as well as Turkey, Uruguay, and China, representing a cross-section of industry, and official food control and research institutes. The method is based on immunoaffinity column cleanup followed by high-performance liquid chromatography using fluorimetry (HPLC-FI). The test portion of the sample is extracted with methanol-water (75 + 25, v/v). The sample extract is filtered, diluted, and passed over an immunoaffinity column. ZON is eluted with methanol. The separation and determination of ZON is performed by reversed-phase HPLC-FI with an excitation wavelength of 274 nm and an emission wavelength of 446 nm. Test portions of the samples were spiked at levels of 20 and 30 microg/kg ZON in baby food and at levels of 100 and 150 microg/kg ZON in animal feed. Mean recoveries from each participant ranged from 78 to 119% with an average value of 92% for baby food and from 51 to 122% with an average value of 74% for animal feed. Based on results for spiked samples (blind duplicates at 2 levels), as well as naturally contaminated samples (blind duplicates at 3 levels), the relative standard deviation for repeatability (RSDr) in baby food ranged from 2.8 to 9.0%. For animal feed, this value ranged from 5.7 to 9.5%. The relative standard deviation for reproducibility (RSDR) in baby food ranged from 8.2 to 13.3%, and for animal feed this value ranged from 15.5 to 21.4%. The Horwitz ratio (HorRat) in baby food ranged from 0.3 to 0.4, and for animal feed this value ranged from 0.6 to 0.9. The method showed acceptable within- and between-laboratory precision for each matrix, as required by European legislation.

  12. New Micellar Electrokinetic Chromatographic Method for Analyzing Idebenone in Pediatric Formulations.

    Science.gov (United States)

    Contin, Mario; Buontempo, Fabián; García Becerra, Cristian; Dobrecky, Cecilia; Lucangioli, Silvia; Tripodi, Valeria

    2017-03-01

    A novel, simple and reliable method based on micellar electrokinetic chromatography with ultraviolet detection was developed to analyze idebenone in a pediatric formulation. Idebenone is a synthetic short chain benzoquinone that acts as an electron carrier in the mitochondrial electron transport chain facilitating the production of adenosine triphosphate. It can be found in two different redox states that differ in their physiological properties. Idebenone has been investigated as a treatment in several neurological disorders like Friedreich's ataxia, Leber's hereditary optic neuropathy, mitochondrial encephalomyopathies and senile dementia. Accordingly, a micellar electrokinetic chromatography was employed to discriminate both redox forms. The final optimized system was validated in terms of selectivity, linearity (r2 0.992), limit of detection (0.5 µg/mL), limit of quantification (1.8 µg/mL), intra- and inter-day precision (RSD ≤ 2) and accuracy in terms of recovery studies (99.3-100.5%). Robustness was studied following a Plackett-Burman design. Finally, the validated system was applied to the analysis of idebenone in a pediatric formulation. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. Determination of Profenofos Pesticidal Residue in Lettuce (Lactuca sativa L. by Gas Chromatographic Method

    Directory of Open Access Journals (Sweden)

    Yohannes Alen

    2015-05-01

    Full Text Available The determination of profenofos pesticidal residue in the lettuce (Lactuca sativa L. by using gas chromatography using flame photometric detector (FPD had been investigated. The lettuce was collected from Padang Luar area, Agam distric, West Sumatera. Sample for determination of profenofos residue divided into three groups: unwashed (A, washed with water (B, and washed with detergent (C. Maceration with sonication was used for the extraction using ethylacetateas a solvent. The results showed that profenofos pesticide residue in sample A, B and C were 0.204, 0.080 and 0.061 ppm, respectively. These profenofos pesticidal residue are over than the Maximum Residue Limits (MRL that established by The Japan Food Chemical Research Foundation (0.05 ppm even though World Health Organization (WHO has not established Maximum Residue Limits (MRL profenofos on lettuce. Based on the statistical analysis one-way method (Anova using SPSS 20.0 showed that there was a significant concentrations difference between lettuce A from lettuce B and lettuce C with p < 0.05.

  14. A new method for total OH reactivity measurements using a fast Gas Chromatographic Photo-Ionization Detector (GC-PID)

    Science.gov (United States)

    Nölscher, A. C.; Sinha, V.; Bockisch, S.; Klüpfel, T.; Williams, J.

    2012-05-01

    The primary and most important oxidant in the atmosphere is the hydroxyl radical (OH). Currently OH sinks, particularly gas phase reactions, are poorly constrained. One way to characterize the overall sink of OH is to measure directly the ambient loss rate of OH, the total OH reactivity. To date direct measurements of total OH reactivity have been either performed using a Laser Induced Fluorescence (LIF) system ("pump-and-probe" or "flow reactor") or the Comparative Reactivity Method (CRM) with a Proton Transfer Reaction Mass Spectrometer (PTR-MS). Both techniques require large, complex and expensive detection systems. This study presents a feasibility assessment for CRM total OH reactivity measurements using a new detector, a Gas Chromatographic Photo-Ionization Detector (GC-PID). Such a system is smaller, more portable, less power consuming and less expensive than other total OH reactivity measurement techniques. Total OH reactivity is measured by the CRM using a competitive reaction between a reagent (here pyrrole) with OH alone and in the presence of atmospheric reactive molecules. The new CRM method for total OH reactivity has been tested with parallel measurements of the GC-PID and the previously validated PTR-MS as detector for the reagent pyrrole during laboratory experiments, plant chamber and boreal field studies. Excellent agreement of both detectors was found when the GC-PID was operated under optimum conditions. Time resolution (60-70 s), sensitivity (LOD 3-6 s-1) and overall uncertainty (25% in optimum conditions) for total OH reactivity were equivalent to PTR-MS based total OH reactivity measurements. One drawback of the GC-PID system was the steady loss of sensitivity and accuracy during intensive measurements lasting several weeks, and a possible toluene interference. Generally, the GC-PID system has been shown to produce closely comparable results to the PTR-MS and thus in suitable environments (e.g. forests) it presents a viably economical

  15. Determination of residual acetone and acetone related impurities in drug product intermediates prepared as Spray Dried Dispersions (SDD) using gas chromatography with headspace autosampling (GCHS).

    Science.gov (United States)

    Quirk, Emma; Doggett, Adrian; Bretnall, Alison

    2014-08-05

    Spray Dried Dispersions (SDD) are uniform mixtures of a specific ratio of amorphous active pharmaceutical ingredient (API) and polymer prepared via a spray drying process. Volatile solvents are employed during spray drying to facilitate the formation of the SDD material. Following manufacture, analytical methodology is required to determine residual levels of the spray drying solvent and its associated impurities. Due to the high level of polymer in the SDD samples, direct liquid injection with Gas Chromatography (GC) is not a viable option for analysis. This work describes the development and validation of an analytical approach to determine residual levels of acetone and acetone related impurities, mesityl oxide (MO) and diacetone alcohol (DAA), in drug product intermediates prepared as SDDs using GC with headspace (HS) autosampling. The method development for these analytes presented a number of analytical challenges which had to be overcome before the levels of the volatiles of interest could be accurately quantified. GCHS could be used after two critical factors were implemented; (1) calculation and application of conversion factors to 'correct' for the reactions occurring between acetone, MO and DAA during generation of the headspace volume for analysis, and the addition of an equivalent amount of polymer into all reference solutions used for quantitation to ensure comparability between the headspace volumes generated for both samples and external standards. This work describes the method development and optimisation of the standard preparation, the headspace autosampler operating parameters and the chromatographic conditions, together with a summary of the validation of the methodology. The approach has been demonstrated to be robust and suitable to accurately determine levels of acetone, MO and DAA in SDD materials over the linear concentration range 0.008-0.4μL/mL, with minimum quantitation limits of 20ppm for acetone and MO, and 80ppm for DAA. Copyright

  16. Optimization of chromatographic conditions and comparison of extraction efficiencies of four different methods for determination and quantification of pesticide content in bovine milk by UFLC-MS/MS

    Directory of Open Access Journals (Sweden)

    Fabiano A. S. Oliveira

    2014-01-01

    Full Text Available This paper describes the optimization of a multiresidue chromatographic analysis for the identification and quantification of 20 pesticides in bovine milk, including three carbamates, a carbamate oxime, six organophosphates, two strobilurins, a pyrethroid, an oxazolidinedione, an aryloxyphenoxypropionate acid/ester, a neonicotinoid, a dicarboximide, and three triazoles. The influences of different chromatographic columns and gradients were evaluated. Furthermore, four different extraction methods were evaluated; each utilized both different solvents, including ethyl acetate, methanol, and acetonitrile, and different workup steps. The best results were obtained by a modified QuEChERS method that lacked a workup step, and that included freezing the sample for 2 hours at -20 ºC. The results were satisfactory, yielding coefficients of variation of less than 20%, with the exception of the 50 µg L-1 sample of famoxadone, and recoveries between 70 and 120%, with the exception of acephate and bifenthrin; however, both analytes exhibited coefficients of variation of less than 20%.

  17. Bepaling van tetrachloor- en trichloorethyleen in olijfolie met behulp van headspace - gaschromatografie

    NARCIS (Netherlands)

    Roos, A.H.; Mazijk, van R.J.; Tuinstra, L.G.M.Th.

    1990-01-01

    De resultaten van de EEG headspace methode wijzen uit dat de herhaalbaarheid en nauwkeurigheid voldoende zijn om tetrachloor- en trichloorethyleen in olijfolie te bepalen tot een niveau van 0,01 mg/kg op produkt. De headspace techniek is door de eenvoudige procedure zeer geschikt voor routine

  18. Simplex Optimization of Headspace-Enrichment Conditions of Residual Petroleum Distillates Used by Arsonists

    Science.gov (United States)

    Warnke, Molly M.; Erickson, Angela E.; Smith, Eugene T.

    2005-01-01

    A forensic project is described that is suitable for an undergraduate instrumental methods lab. Accelerants commonly used by arsonists are analyzed by static headspace enrichment followed by gas chromatography. The conditions used for headspace enrichment (e.g., time and temperature) are known to influence the distribution of hydrocarbons…

  19. DISSOLVED OXYGEN AND METHANE IN WATER BY A GC HEADSPACE EQUILIBRATION TECHNIQUE

    Science.gov (United States)

    An analytical procedure is described for the determination of dissolved oxygen and methane in groundwater samples. The method consists of generating a helium gas headspace in a water filled bottle, and analysis of the headspace by gas chromatography. Other permanent gases such as...

  20. Bepaling van tetrachloor- en trichloorethyleen in olijfolie met behulp van headspace - gaschromatografie

    OpenAIRE

    Roos, A.H.; Mazijk, van, R.J.; Tuinstra, L. G M Th

    1990-01-01

    De resultaten van de EEG headspace methode wijzen uit dat de herhaalbaarheid en nauwkeurigheid voldoende zijn om tetrachloor- en trichloorethyleen in olijfolie te bepalen tot een niveau van 0,01 mg/kg op produkt. De headspace techniek is door de eenvoudige procedure zeer geschikt voor routine analyse.

  1. VALIDATION OF AN EPA METHOD FOR THE ION CHROMATOGRAPHIC DETERMINATION OF PERCHLORATE IN FERTILIZERS USING A POLYVINYL ALCOHOL GEL RESIN.

    Science.gov (United States)

    This paper summarizes the key points of a joint study between the EPA and Metrohm-Peak, Inc., on the use of polyvinyl alcohol [PVA] columns for the ion chromatographic determination of percholorate in aqueous leachates or solutions of fertilizers. A series of fertilizer samples ...

  2. A validated high performance liquid chromatograph-photodiode array method for simultaneous determination of 10 bioactive components in compound hongdoushan capsule.

    Science.gov (United States)

    Zhu, Liancai; Yang, Xian; Tan, Jun; Wang, Bochu; Zhang, Xue

    2014-01-01

    The compound Hongdoushan capsule (CHC) is widely known as compound herbal preparation and is often used to treat ovarian cancer and breast cancer, and to enhance the body immunity, etc., in clinical practice. To determine simultaneously 10 bioactive components from CHC, namely glycyrrhetinic acid, liquiritin, glycyrrhizin, baccatin III, 10-deacetylbaccatin III, cephalomannine, taxol, ginsenoside Rg1, ginsenoside Re, and ginsenoside Rb1. A high performance liquid chromatograph method coupled with photodiode array detector was developed and validated for the 1(st) time. Chromatographic analysis was performed on a SHIMADZU C18 by utilizing a gradient elution program. The mobile phase was acetonitrile (A)-water (B) at a flow rate of 0.8 mL/min. The calibration curve was linear over the investigated concentration ranges with the values of r (2) higher than 0.9993 for all the 10 bioactive components. The average recovery rates range from 98.4% to 100.5% with relative standard deviations ≤2.9%. The developed method was successfully applied to analyze 10 compounds in six CHC samples from different batches. In addition, the herbal sources of 32 chromatographic peaks were identified through comparative studying on chromatograms of standard, the respective extracts of Hongdoushan, RenShen, GanCao, and CHC. All the results imply that the accurate and reproducible method developed has high separation rate and enables the determination of 10 bioactive components in a single run for the quality control of CHC.

  3. Liquid chromatographic determination of ampicillin residues in porcine muscle tissue by a multipenicillin analytical method: European Collaborative Study.

    Science.gov (United States)

    Verdon, Eric; Couëdor, Pierrick; Maris, Pierre; Laurentie, Michel

    2002-01-01

    A collaborative study involving 14 laboratories was conducted to determine residues of ampicillin in porcine muscle tissue by using a liquid chromatographic method developed for multipenicillin analysis that can quantitate 8 penicillin compounds (benzylpenicillin, phenoxymethylpenicillin, ampicillin, amoxicillin, nafcillin, oxacillin, cloxacillin, and dicloxacillin) at trace levels in muscle tissue. This method involves extraction of the penicillins with phosphate buffer, pH 9, followed by cleanup and concentration on a C18 solid-phase extraction column and reaction with benzoic anhydride at 50 degrees C and with 1,2,4-triazole and mercury(II) chloride solution, pH 9.0, at 65 degrees C. The derivatized compounds are eluted isocratically on a C8 column with a mobile phase of acetonitrile and phosphate buffer (pH 6; 0.1 M) containing sodium thiosulfate and the ion-pair reagent tetrabutylammonium hydrogen sulfate. The penicillins are detected by UV absorption at 325 nm. The limit of detection and the limit of determination (quantitation) of the method were calculated to be approximately 3-5 and 25 microg/kg, respectively, in accordance with the criteria of European Union (EU) Decision No. 93/256/EEC. In this first interlaboratory study, collaborators were instructed to monitor 4 different penicillin compounds (benzylpenicillin, phenoxymethylpenicillin, ampicillin, and amoxicillin) by analyzing 8 blind samples of muscle tissue in triplicate. These samples were prepared from 2 materials containing different concentrations of incurred ampicillin (63.5 microg/kg for material No. 1 and 358.1 microg/kg for material No. 2) and 1 blank material. The repeatability relative standard deviation and the reproducibility relative standard deviation were 10.2 and 17.4%, respectively, for material No. 1 and 7.0 and 16.0%, respectively, for material No. 2. These results demonstrate that the method is suitable for the determination of ampicillin residues in muscle tissue at the EU

  4. Validation of liquid chromatographic method for analysis of lidocaine hydrochloride, dexamethasone acetate, calcium dobesilate, buthylhydroxyanisol and degradation product hydroquinone in suppositories and ointment.

    Science.gov (United States)

    Zivanovic, Lj; Zecevic, M; Markovic, S; Petrovic, S; Ivanovic, I

    2005-09-23

    In this paper, there was developed a sensitive, precise and accurate reversed-phase liquid chromatographic (RP-HPLC) method and validated for simultaneous determination of lidocaine hydrochloride, dexamethasone acetate (DA) and calcium dobesilate (CD) in suppositories and ointment. Also there was achieved a parallel analysis of buthylhydroxyanisol, as a preservative, and hydroquinone, as a degradation product of calcium dobesilate, present in these dosage forms. The relative standard deviation (RSD) values for all five compounds indicated a good precision and accuracy of the RP-HPLC method. Method is selective, sensitive and reproducible with good recovery values and can be applied in simultaneous determination of all mentioned compounds.

  5. Determination of sulfur dioxide in grapes: comparison of the Monier-Williams method and two ion exclusion chromatographic methods.

    Science.gov (United States)

    Kim, H J; Conca, K R; Richardson, M J

    1990-01-01

    Results for determination of sulfur dioxide in grapes were compared by 3 methods: the modified Monier-Williams method, acid distillation/ion exclusion chromatography with electrochemical detection (AD/IEC-EC), and alkali extraction/ion exclusion chromatography with electrochemical detection (AE/IEC-EC). An unusual positive response was observed during the later stage of the Monier-Williams distillation of both control grapes and sulfited grapes. Development of volatile acidic compounds in parallel with this Monier-Williams response and darkening of sample was also observed by collection in an alkali trap and analysis using anion exclusion chromatography and photodiode array detection. No parallel increase in sulfite was observed by the more selective AD/IEC-EC method, which clearly demonstrated that the response observed during the later stage of the Monier-Williams method is a false positive, probably due to caramelization reaction products. Monier-Williams results for grapes containing ca 10 ppm sulfite were in reasonably good agreement with those by either the AD/IEC-EC or AE/IEC-EC methods, presumably because the false positive response in the Monier-Williams analysis compensated for the somewhat incomplete recovery of sulfite. The AE/IEC-EC method is recommended because it is rapid, sensitive, straightforward, and free from interference. Accurate results by Monier-Williams analysis could be obtained by limiting distillation to 60 min and correcting for recovery.

  6. Optimisation of a headspace-solid-phase micro-extraction method for simultaneous determination of organometallic compounds of mercury, lead and tin in water by gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Beceiro-González, E; Guimaraes, A; Alpendurada, M F

    2009-07-17

    In this work, a headspace-solid-phase micro-extraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS) method for multielemental speciation of organometallic compounds of mercury, lead and tin in water samples was upgraded by the introduction of tandem mass spectrometry (MS/MS) as detection technique. The analytical method is based on the ethylation with NaBEt(4) and simultaneous headspace-solid-phase micro-extraction of the derivative compounds followed by GC-MS/MS analysis. The main experimental parameters influencing the extraction efficiency such as derivatisation time, extraction time and extraction temperature were optimized. The overall optimum extraction conditions were the following: a 50 microm/30 microm divinyl-benzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) SPME fibre, 150 min derivatisation time, 15 min extraction time, sample agitation at 250 rpm and 40 degrees C extraction temperature. The analytical characteristics of the HS-SPME method combined with GC-MS and GC-MS/MS were evaluated. The combination of both techniques HS-SPME and GC-MS/MS allowed to attain lower limits of detection (4-33 ng l(-1)) than those obtained by HS-SPME-GC-MS (17-45 ng l(-1)). The proposed method presented good linear regression coefficients (r(2)>0.9970) and repeatability (4.8-21.0%) for all the compounds under study. The accuracy of the method measured as the average percentage recovery of the compounds in spiked river water and seawater samples was higher than 80% for all the compounds studied, except for monobutyltin in the river water sample. A study of the uncertainty associated with the analytical results was also carried out.

  7. Extraction chromatographic method of preconcentration, estimation and concomitant separation of vanadium (IV) with silica gel-versatic 10 composite.

    Science.gov (United States)

    Mandal, Bhabatosh; Barman, Milan K; Srivastava, Bhavya

    2014-10-01

    A selective method has been developed for the extraction chromatographic separation of V(IV) with SSG-V-10 composite. V(IV) was quantitatively extracted at pH 5.0-6.0, and its loading has been confirmed by EDAX. XRD studies indicate that the SSG network does not get influenced by impregnation with V-10 or by the sorption of V(IV) on the surface of SSG-V-10 composite. The binding between SSG and V-10 is a hydrophobic interaction only, and it takes place at the surface of the hydrophobic SSG. TGA-DTA analysis indicates its thermal stability up to 45°C. The exchange capacity (1.65 meq of H(+) g(-1)), break-through capacity (34.5 mg g(-1)) and column efficiency (360) of the extractor have been rationalized by Brunauer-Emmett-Teller analysis (SA = 149.46 m(2) g(-1) and PV = 0.2001 mL g(-1) at a relative pressure of 0.9-1.0). The sorption process was endothermic (ΔH = 12.63 kJ mol(-1)), entropy gaining (ΔS = 0.271 kJ mol(-1) K(-1)) and spontaneous (ΔG = -68.241 kJ mol(-1)) in nature. Preconcentration factor has been optimized at 182.3 ± 0.2. Formation constants (Kf) of the metal centers [Zn(II) (0.6 × 10(3)), Cd(II) (0.9 × 10(4)), Pb(II) (0.6 × 10(5)), Cu(II) (0.2 × 10(5)), Al(III) (6.2 × 10(5)), Ga(III) (4.2 × 10(5)), Hg(II) (2.2 × 10(6)), Bi(III) (6.2 × 10(6)), Tl(III) (8.9 × 10(6)), Zr(IV) (6.8 × 10(9)), Fe(III) (0.9 × 10(9)) and V(IV) (0.8 × 10(6))] have been determined. The desorption constants Kdesorption (1.9 × 10(-2)) and [Formula: see text] have been determined. Rf values and selectivity factors for diverse metal ions have been determined. V(IV) has been separated from the synthetic and real samples containing its congeners. A plausible mechanism for the extraction of V(IV) has been suggested. © The Author [2013]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Response-to-comments about: "Is it really the method for carbon dioxide determination in human postmortem cardiac gas samples using Headspace-Gas Chromatography-Mass Spectrometry valid?" from T. Saffaj and B. Ihssane.

    Science.gov (United States)

    Varlet, Vincent

    2014-01-31

    Saffaj et al. recently criticized our method of monitoring carbon dioxide in human postmortem cardiac gas samples using Headspace-Gas Chromatography-Mass Spectrometry. According to the authors, their demonstration, based on the latest SFSTP guidelines (established after 2007) fitted for the validation of drug monitoring bioanalytical methods, has put in evidence potential errors. However, our validation approach was built using SFSTP guidelines established before 2007. We justify the use of these guidelines because of the post-mortem context of the study (and not clinical) and the gaseous state of the sample (and not solid or liquid). Using these guidelines, our validation remains correct. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. An Effective Method to Detect Volatile Intermediates Generated in the Bioconversion of Coal to Methane by Gas Chromatography-Mass Spectrometry after In-Situ Extraction Using Headspace Solid-Phase Micro-Extraction under Strict Anaerobic Conditions

    Science.gov (United States)

    Liu, Jianmin; Wang, Baoyu; Tai, Chao; Wu, Li; Zhao, Han; Guan, Jiadong; Chen, Linyong

    2016-01-01

    Bioconversion of coal to methane has gained increased attention in recent decades because of its economic and environmental advantages. However, the mechanism of this process is difficult to study in depth, partly because of difficulties associated with the analysis of intermediates generated in coal bioconversion. In this investigation, we report on an effective method to analyze volatile intermediates generated in the bioconversion of coal under strict anaerobic conditions. We conduct in-situ extraction of intermediates using headspace solid-phase micro-extraction followed by detection by gas chromatography-mass spectrometry. Bioconversion simulation equipment was modified and combined with a solid-phase micro-extraction device. In-situ extraction could be achieved by using the combined units, to avoid a breakdown in anaerobic conditions and to maintain the experiment continuity. More than 30 intermediates were identified qualitatively in the conversion process, and the variation in trends of some typical intermediates has been discussed. Volatile organic acids (C2–C7) were chosen for a quantitative study of the intermediates because of their importance during coal bioconversion to methane. Fiber coating, extraction time, and solution acidity were optimized in the solid-phase micro-extraction procedure. The pressure was enhanced during the bioconversion process to investigate the influence of headspace pressure on analyte extraction. The detection limits of the method ranged from 0.0006 to 0.02 mmol/L for the volatile organic acids and the relative standard deviations were between 4.6% and 11.5%. The volatile organic acids (C2–C7) generated in the bioconversion process were 0.01–1.15 mmol/L with a recovery range from 80% to 105%. The developed method is useful for further in-depth research on the bioconversion of coal to methane. PMID:27695055

  10. Effect of Subcritical Fluid Extraction on the High Quality of Headspace Oil from Jasminum sambac (L.) Aiton.

    Science.gov (United States)

    Ye, Qiuping; Jin, Xinyi; Wei, Shiqin; Zheng, Gongyu; Li, Xinlei

    2016-05-01

    Subcritical fluid extraction (SFE), as a novel method, was applied to investigate the yield, quality, and sensory evaluation of headspace oil from Jasminum sambac (L.) Aiton in comparison with petroleum ether extraction (PEE). The results indicated that the yield of the headspace oil using SFE was significantly higher (P headspace oil. The contents of linalool (21.90%) and benzyl acetate (16.31%) were higher via SFE than PEE. In addition, the sensory evaluation of SFE was superior to PEE, indicating a fresh, jasmine-like odor and green-yellow color. Thus, SFE is an improved method for obtaining natural headspace oil from jasmine flowers.

  11. Effect of Subcritical Fluid Extraction on the High Quality of Headspace Oil from Jasminum sambac (L.) Aiton.

    Science.gov (United States)

    2016-04-22

    Subcritical fluid extraction (SFE), as a novel method, was applied to investigate the yield, quality, and sensory evaluation of headspace oil from Jasminum sambac (L.) Aiton in comparison with petroleum ether extraction (PEE). The results indicated that the yield of the headspace oil using SFE was significantly higher (P headspace oil. The contents of linalool (21.90%) and benzyl acetate (16.31%) were higher via SFE than PEE. In addition, the sensory evaluation of SFE was superior to PEE, indicating a fresh, jasmine-like odor and green-yellow color. Thus, SFE is an improved method for obtaining natural headspace oil from jasmine flowers.

  12. Development and validation of a stability-indicating high performance liquid chromatographic (HPLC) method for the determination of related substances of micafungin sodium in drug substances.

    Science.gov (United States)

    Zhu, Shengsheng; Meng, Xiang; Su, Xin; Luo, Yongwei; Sun, Zuyue

    2013-10-24

    An isocratic, sensitive and stability-indicating high performance liquid chromatographic (HPLC) method for separation and determination of the related substances of micafungin sodium was developed. The chromatographic separation was achieved on Agilent Zorbax SB-C18 column (250 × 4.6 mm, 5 μm). Forced degradation study confirmed that the newly developed method was specific and selective to the degradation products. The performance of the method was validated according to the present ICH guidelines for specificity, linearity, accuracy, precision and robustness. Regression analysis showed correlation coefficient value greater than 0.999 for micafungin sodium and its six impurities. Limit of detection of impurities was in the range of 0.006%-0.013% indicating the high sensitivity of the newly developed method. Accuracy of the method was established based on the recovery obtained between 98.2% and 102.0% for all impurities. RSD obtained for the repeatability and intermediate precision experiments, was less than 1.0%. The method was successfully applied to quantify related substances of micafungin sodium in bulk drugs.

  13. Ethanol analysis by headspace gas chromatography with simultaneous flame-ionization and mass spectrometry detection.

    Science.gov (United States)

    Tiscione, Nicholas B; Alford, Ilene; Yeatman, Dustin Tate; Shan, Xiaoqin

    2011-09-01

    Ethanol is the most frequently identified compound in forensic toxicology. Although confirmation involving mass spectrometry is desirable, relatively few methods have been published to date. A novel technique utilizing a Dean's Switch to simultaneously quantitate and confirm ethyl alcohol by flame-ionization (FID) and mass spectrometric (MS) detection after headspace sampling and gas chromatographic separation is presented. Using 100 μL of sample, the limits of detection and quantitation were 0.005 and 0.010 g/dL, respectively. The zero-order linear range (r(2) > 0.990) was determined to span the concentrations of 0.010 to 1.000 g/dL. The coefficient of variation of replicate analyses was less than 3.1%. Quantitative accuracy was within ±8%, ±6%, ±3%, and ±1.5% at concentrations of 0.010, 0.025, 0.080, and 0.300 g/dL, respectively. In addition, 1,1-difluoroethane was validated for qualitative identification by this method. The validated FID-MS method provides a procedure for the quantitation of ethyl alcohol in blood by FID with simultaneous confirmation by MS and can also be utilized as an identification method for inhalants such as 1,1-difluoroethane.

  14. [Simultaneous determination of seven residual solvents in bovis calculus artifactus by headspace gas chromatography].

    Science.gov (United States)

    Chi, Shuyao; Wu, Dike; Sun, Jinhong; Ye, Ruhan; Wang, Xiaoyan

    2014-05-01

    A headspace gas chromatography (HS-GC) method was developed for the simultaneous determination of seven residual solvents (petroleum ether (60-90 degrees C), acetone, ethyl acetate, methanol, methylene chloride, ethanol and butyl acetate) in bovis calculus artifactus. The DB-WAX capillary column and flame ionization detector (FID) were used for the separation and detection of the residual solvents, and the internal standard method was used for the quantification. The chromatographic conditions, such as equilibrium temperature and equilibrium time, were optimized. Under the optimized conditions, all of the seven residual solvents showed good linear relationships with good correlation coefficients (not less than 0.999 3) in the prescribed concentration range. At three spiked levels, the recoveries for the seven residual solvents were 94.7%-105.2% with the relative standard deviations (RSDs) less than 3.5%. The limits of detection (LODs) of the method were 0.43-5.23 mg/L, and the limits of quantification (LOQs) were 1.25-16.67 mg/L. The method is simple, rapid, sensitive and accurate, and is suitable for the simultaneous determination of the seven residual solvents in bovis calculus artifactus.

  15. Headspace solid-phase microextraction and gas chromatography ...

    African Journals Online (AJOL)

    Purpose: To extract and analyze the volatile components of Chrysanthemum morifolium Ramat. 'huaiju' by headspace solid-phase microextraction (HS-SPME) and gas chromatography–mass spectrometry (GC–MS). Methods: Volatile components were extracted by HS-SPME and identified by GC–MS. The relative contents ...

  16. Headspace solid-phase microextraction and gas chromatography ...

    African Journals Online (AJOL)

    Purpose: To extract and analyze the volatile components of Chrysanthemum morifolium Ramat. 'huaiju' by headspace solid-phase microextraction (HS-SPME) and gas chromatography–mass spectrometry. (GC–MS). Methods: Volatile components were extracted by HS-SPME and identified by GC–MS. The relative contents ...

  17. Measurement of Fluoride in Human Urine by Headspace Gas Chromatography-Mass Spectrometer

    National Research Council Canada - National Science Library

    Tsuda, Yoko; Otsuka, Takao; Tsukahara, Teruomi; Nomiyama, Tetsuo

    2016-01-01

    Objective: The aim of this study is to establish a simple sample preparation method for analysis of fluoride in biological materials with headspace gas chromatography-mass spectrometer (HS GC-MS).Methods...

  18. Disposable remote zero headspace extractor

    Science.gov (United States)

    Hand, Julie J.; Roberts, Mark P.

    2006-03-21

    The remote zero headspace extractor uses a sampling container inside a stainless steel vessel to perform toxicity characteristics leaching procedure to analyze volatile organic compounds. The system uses an in line filter for ease of replacement. This eliminates cleaning and disassembly of the extractor. All connections are made with quick connect fittings which can be easily replaced. After use, the bag can be removed and disposed of, and a new sampling container is inserted for the next extraction.

  19. Study and ICH validation of a reverse-phase liquid chromatographic method for the quantification of the intact monoclonal antibody cetuximab

    Directory of Open Access Journals (Sweden)

    Antonio Martínez-Ortega

    2016-04-01

    Full Text Available Cetuximab (CTX is a potent chimeric mouse/human monoclonal antibody (mAb approved worldwide for treatment of metastatic colorectal cancer. Among the various biological and physical analyses performed for full study on this biopharmaceutic, the determination of the concentration preparations throughout manufacturing and subsequent handling in hospital is particularly relevant. In the present work, the study and validation of a method for quantifying intact CTX by reverse-phase high-performance liquid chromatography with diode array detection ((RPHPLC/DAD is presented. With that end, we checked the performance of a chromatographic method for quantifying CTX and conducted a study to validate the method as stability-indicating in accordance with the International Conference on Harmonization guidelines (ICH for biotechnological drugs; therefore, we evaluated linearity, accuracy, precision, detection and quantification limits, robustness and system suitability. The specificity of the method and the robustness of the mAb formulation against external stress factors were estimated by comprehensive chromatographic analysis by subjecting CTX to several informative stress conditions. As demonstrated, the method is rapid, accurate, and reproducible for CTX quantification. It was also successfully used to quantify CTX in a long-term stability study performed under hospital conditions.

  20. Development and validation of an high-performance liquid chromatographic, and a ultraviolet spectrophotometric method for determination of Ambroxol hydrochloride in pharmaceutical preparations

    Science.gov (United States)

    Muralidharan, Selvadurai; Kumar, Jaya Raja; Dhanara, Sokkalingam Arumugam

    2013-01-01

    A high-performance liquid chromatographic (HPLC) and ultraviolet (UV) methods were developed and validated for the quantitative determination of Ambroxol hydrochloride (AMH) in pharmaceutical dosage form. HPLC was carried out by reversed phase (RP) technique on an RP-18 column with a mobile phase composed of acetonitrile and water (pH 3.5 adjusted with orthophosphoric acid [60:40, v/v]). UV method was performed with the λmax at 250 nm. Both the methods showed good linearity, reproducibility, and precision. No spectral or chromatographic interferences from the tablet excipients were found in UV and HPLC. The method was successfully applied to commercial tablets. Validation parameters such as linearity, precision, accuracy, and specificity were determined. The HPLC Limit of detection (LOD) and Limit of quantification (LOQ) for Ambroxol were found to be 1 and 5 ng/ml, respectively. The UV LOD and LOQ for Ambroxol were found to be 1 and 4 μg/ml, respectively. The results were statistically compared using one-way analysis of variance. The proposed economical method could be applicable for routine analysis of AMH and monitoring of the quality of marketed drugs. PMID:23662284

  1. Development and validation of an high-performance liquid chromatographic, and a ultraviolet spectrophotometric method for determination of Ambroxol hydrochloride in pharmaceutical preparations

    Directory of Open Access Journals (Sweden)

    Selvadurai Muralidharan

    2013-01-01

    Full Text Available A high-performance liquid chromatographic (HPLC and ultraviolet (UV methods were developed and validated for the quantitative determination of Ambroxol hydrochloride (AMH in pharmaceutical dosage form. HPLC was carried out by reversed phase (RP technique on an RP-18 column with a mobile phase composed of acetonitrile and water (pH 3.5 adjusted with orthophosphoric acid [60:40, v/v]. UV method was performed with the λmax at 250 nm. Both the methods showed good linearity, reproducibility, and precision. No spectral or chromatographic interferences from the tablet excipients were found in UV and HPLC. The method was successfully applied to commercial tablets. Validation parameters such as linearity, precision, accuracy, and specificity were determined. The HPLC Limit of detection (LOD and Limit of quantification (LOQ for Ambroxol were found to be 1 and 5 ng/ml, respectively. The UV LOD and LOQ for Ambroxol were found to be 1 and 4 μg/ml, respectively. The results were statistically compared using one-way analysis of variance. The proposed economical method could be applicable for routine analysis of AMH and monitoring of the quality of marketed drugs.

  2. Methods to assess secondary volatile lipid oxidation products in complex food matrices

    DEFF Research Database (Denmark)

    Jacobsen, Charlotte; Yesiltas, Betül

    and hexanal. Different extraction methods for extracting volatiles before GC analysis can be used, e.g static headspace, dynamic headspace and solid phase microextraction. Traditionally, dynamic headspace extraction has been performed manually. However, recently automated dynamic headspace methods have become...... headspace methods on the same food matrices will be presented....

  3. Headspace solid-phase microextraction gas chromatography-mass spectrometry analysis of volatiles in orujo spirits from a defined geographical origin.

    Science.gov (United States)

    Peña, Rosa M; Barciela, Julia; Herrero, Carlos; García-Martín, Sagrario

    2008-04-23

    A headspace solid-phase microextraction (HS-SPME) and gas chromatography-selective ion monitoring/mass spectrometry (GC-SIM/MS) method was optimized for analysis of 22 volatile compounds in orujo spirit samples from the Geographic Denomination "Orujo de Galicia/Augardente de Galicia". HS-SPME experimental conditions, such as fiber coating, extraction temperature, extraction and pre-equilibrium time, sample volume, and the presence of salt, were studied to improve the extraction process. The best results were obtained using a 65 microm Carbowax-divinylbenzene fiber during a headspace extraction at 40 degrees C with constant magnetic stirring for 15 min and after a 5 min period of pre-equilibrium time. The sample volume was 6 mL of orujo containing 25% of NaCl, placed in 12 mL glass vials equipped with a screw cap and PTFE/silicone septum. Desorption was performed directly in the gas chromatograph injector port for 5 min at 250 degrees C using the splitless mode. The proposed method is sensible (with detection limits between 0.0045 and 0.2399 mg/L), precise (with coefficients of variation in the range 0.99-8.18%), and linear over more than 1 order of magnitude. The developed method presented recoveries comprised between 76.0 and 112.4%. The applicability of the new method was demonstrated by determining the considered 22 volatile compounds in nine orujo commercial samples with quality and origin brands.

  4. A rapid gas chromatographic injection-port derivatization method for the tandem mass spectrometric determination of patulin and 5-hydroxymethylfurfural in fruit juices.

    Science.gov (United States)

    Marsol-Vall, Alexis; Balcells, Mercè; Eras, Jordi; Canela-Garayoa, Ramon

    2016-07-01

    A novel method consisting of injection-port derivatization coupled to gas chromatography-tandem mass spectrometry is described. The method allows the rapid assessment of 5-hydroxymethylfurfural (HMF) and patulin content in apple and pear derivatives. The chromatographic separation of the compounds was achieved in a short chromatographic run (12.2min) suitable for routine controls of these compounds in the fruit juice industry. The optimal conditions for the injection-port derivatization were at 270°C, 0.5min purge-off, and a 1:2 sample:derivatization reagent ratio (v/v). These conditions represent an important saving in terms of derivatization reagent consumption and sample preparation time. Quality parameters were assessed for the target compounds, giving LOD of 0.7 and 1.6μg/kg and LOQ of 2 and 5μg/kg for patulin and HMF, respectively. These values are below the maximum patulin concentration in food products intended for infants and young children. Repeatability (%RSD n=5) was below 12% for both compounds. In addition, the method linearity ranged between 25 and 1000μg/kg and between 5 and 192μg/kg for HMF and patulin, respectively. Finally, the method was applied to study HMF and patulin content in various fruit juice samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Development and validation of reverse phase-high performance liquid chromatographic method for simultaneous estimation of naproxen sodium and esomeprazole magnesium trihydrate

    Directory of Open Access Journals (Sweden)

    Sampath Saravanan

    2014-01-01

    Full Text Available Background: Naproxen sodium (NAP is a non steroidal anti-inflammatory drug and Esomeprazole magnesium trihydrate (ESO is a proton pump inhibitor. Aim: A high performance liquid chromatographic method was developed and validated for the quantitative determination of naproxen (NAP sodium and esomeprazole (ESO magnesium trihydrate. The different analytical parameters such as linearity, precision, accuracy, limit of detection and limit of quantification were determined according to the International conference harmonization (ICH Q2B guidelines. Materials: Chromatography was carried out by isocratic technique on a reversed phase C18 base deactivated silanol hypersil column with mobile phase and optimized depending upon the polarity of the molecules. Results: The calibration curves were linear (r2 > 0.9997 over the concentrations 20-120 μg/mL for NAP sodium and 0.8-4.8 μg/mL for ESO magnesium trihydrate. The method was accurate and precise with recoveries in the range of 99.48-99.98% for the two drugs and relative standard deviation less than 2%. No chromatographic interferences from the tablet excipients were found. Conclusion: The proposed method was highly sensitive, precise and accurate. Hence the method was successfully applied for the reliable quantification of active pharmaceutical ingredients content in house prepared tablet formulation of NAP sodium and EOS magnesium trihydrate.

  6. Optimization and validation of liquid chromatography and headspace-gas chromatography based methods for the quantitative determination of capsaicinoids, salicylic acid, glycol monosalicylate, methyl salicylate, ethyl salicylate, camphor and l-menthol in a topical formulation.

    Science.gov (United States)

    Pauwels, Jochen; D'Autry, Ward; Van den Bossche, Larissa; Dewever, Cédric; Forier, Michel; Vandenwaeyenberg, Stephanie; Wolfs, Kris; Hoogmartens, Jos; Van Schepdael, Ann; Adams, Erwin

    2012-02-23

    Capsaicinoids, salicylic acid, methyl and ethyl salicylate, glycol monosalicylate, camphor and l-menthol are widely used in topical formulations to relieve local pain. For each separate compound or simple mixtures, quantitative analysis methods are reported. However, for a mixture containing all above mentioned active compounds, no assay methods were found. Due to the differing physicochemical characteristics, two methods were developed and optimized simultaneously. The non-volatile capsaicinoids, salicylic acid and glycol monosalicylate were analyzed with liquid chromatography following liquid-liquid extraction, whereas the volatile compounds were analyzed with static headspace-gas chromatography. For the latter method, liquid paraffin was selected as compatible dilution solvent. The optimized methods were validated in terms of specificity, linearity, accuracy and precision in a range of 80% to 120% of the expected concentrations. For both methods, peaks were well separated without interference of other compounds. Linear relationships were demonstrated with R² values higher than 0.996 for all compounds. Accuracy was assessed by performing replicate recovery experiments with spiked blank samples. Mean recovery values were all between 98% and 102%. Precision was checked at three levels: system repeatability, method precision and intermediate precision. Both methods were found to be acceptably precise at all three levels. Finally, the method was successfully applied to the analysis of some real samples (cutaneous sticks). Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Validated high-performance thin-layer chromatographic (HPTLC method for simultaneous determination of nadifloxacin, mometasone furoate, and miconazole nitrate cream using fractional factorial design

    Directory of Open Access Journals (Sweden)

    Kalpana G. Patel

    2016-07-01

    Full Text Available A high-performance thin-layer chromatographic method for simultaneous determination of nadifloxacin, mometasone furoate, and miconazole nitrate was developed and validated as per International Conference on Harmonization guidelines. High-performance thin-layer chromatographic separation was performed on aluminum plates precoated with silica gel 60F254 and methanol:ethyl acetate:toluene: acetonitrile:3M ammonium formate in water (1:2.5:6.0:0.3:0.2, % v/v as optimized mobile phase at detection wavelength of 224 nm. The retardation factor (Rf values for nadifloxacin, mometasone furoate, and miconazole nitrate were 0.23, 0.70, and 0.59, respectively. Percent recoveries in terms of accuracy for the marketed formulation were found to be 98.35–99.76%, 99.36–99.65%, and 99.16–100.25% for nadifloxacin, mometasone furoate, and miconazole nitrate, respectively. The pooled percent relative standard deviation for repeatability and intermediate precision studies was found to be < 2% for three target analytes. The effect of four independent variables, methanol content in total mobile phase, wavelength, chamber saturation time, and solvent front, was evaluated by fractional factorial design for robustness testing. Amongst all four factors, volume of methanol in mobile phase appeared to have a possibly significant effect on retention factor of miconazole nitrate compared with the other two drugs nadifloxacin and mometasone furoate, and therefore it was important to be carefully controlled. In summary, a novel, simple, accurate, reproducible, and robust high-performance thin-layer chromatographic method was developed, which would be of use in quality control of these cream formulations.

  8. Non-parametric linear regression of discrete Fourier transform convoluted chromatographic peak responses under non-ideal conditions of internal standard method.

    Science.gov (United States)

    Korany, Mohamed A; Maher, Hadir M; Galal, Shereen M; Fahmy, Ossama T; Ragab, Marwa A A

    2010-11-15

    This manuscript discusses the application of chemometrics to the handling of HPLC response data using the internal standard method (ISM). This was performed on a model mixture containing terbutaline sulphate, guaiphenesin, bromhexine HCl, sodium benzoate and propylparaben as an internal standard. Derivative treatment of chromatographic response data of analyte and internal standard was followed by convolution of the resulting derivative curves using 8-points sin x(i) polynomials (discrete Fourier functions). The response of each analyte signal, its corresponding derivative and convoluted derivative data were divided by that of the internal standard to obtain the corresponding ratio data. This was found beneficial in eliminating different types of interferences. It was successfully applied to handle some of the most common chromatographic problems and non-ideal conditions, namely: overlapping chromatographic peaks and very low analyte concentrations. For example, a significant change in the correlation coefficient of sodium benzoate, in case of overlapping peaks, went from 0.9975 to 0.9998 on applying normal conventional peak area and first derivative under Fourier functions methods, respectively. Also a significant improvement in the precision and accuracy for the determination of synthetic mixtures and dosage forms in non-ideal cases was achieved. For example, in the case of overlapping peaks guaiphenesin mean recovery% and RSD% went from 91.57, 9.83 to 100.04, 0.78 on applying normal conventional peak area and first derivative under Fourier functions methods, respectively. This work also compares the application of Theil's method, a non-parametric regression method, in handling the response ratio data, with the least squares parametric regression method, which is considered the de facto standard method used for regression. Theil's method was found to be superior to the method of least squares as it assumes that errors could occur in both x- and y-directions and

  9. Multiwalled carbon nanotubes-doped polymeric ionic liquids coating for multiple headspace solid-phase microextraction.

    Science.gov (United States)

    Feng, Juanjuan; Sun, Min; Li, Leilei; Wang, Xiaojiao; Duan, Huimin; Luo, Chuannan

    2014-06-01

    Multiple headspace solid-phase microextraction (SPME) has proved high efficiency in analysis of volatile compounds in complex samples. Fibers used in multiple headspace SPME must provide a logarithm relationship between peak areas and extraction times. The aim of this work was to investigate the potential of a carbon nanotube doped-polymeric ionic liquid (PILs) fiber for multiple headspace SPME of 2-naphthol in fruit samples, using gas chromatography (GC) for analysis. Based on theory of multiple headspace SPME, β parameters of fruit and aqueous samples were obtained and used for quantitation. The interference effects of sample matrix on proposed multiple headspace SPME method were investigated and compared with that of headspace SPME by determination of significant differences (P) of peak areas. It showed high independence from matrix effects. The proposed multiple headspace SPME-GC method also exhibited high repeatability (relative standard deviation of 2.56%) and recoveries (81.9-110%) for the analysis of real samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Development and validation of high-perfomance liquid chromatographic method for determination of ofloxacin and lomefloxacin in human plasma

    Directory of Open Access Journals (Sweden)

    DRAGICA ZENDELOVSKA

    2005-12-01

    Full Text Available Ahigh-performance liquid chromatographicmethod for the determination of ofloxacin and lomefloxacin in human plasma has been developed and validated. The effect of organic modifiers on the retention of the investigated drugs was investigated. Asimple isocratic chromatographic assay with UV-detection at 280 nm was performed on a Hibar Lichrospher 100 RP 8 column (250×4.6 mm, 5 mm. Merck, Germany using a mixture of acetonitrile and 0.5 % triethylamine in water (pH adjusted to 2.5 with H3PO4 (15:85, V/V as the mobile phase at flow rate of 1.2 mL min-1. The calibration curves were linear in the concentration ragne of 0.5 – 6.0 mg mL-1 for ofloxacin and 0.2-4.5 mg mL-1 for lomefloxacin.

  11. [Application of robustness test for assessment of the measurement uncertainty at the end of development phase of a chromatographic method for quantification of water-soluble vitamins].

    Science.gov (United States)

    Ihssane, B; Bouchafra, H; El Karbane, M; Azougagh, M; Saffaj, T

    2016-05-01

    We propose in this work an efficient way to evaluate the measurement of uncertainty at the end of the development step of an analytical method, since this assessment provides an indication of the performance of the optimization process. The estimation of the uncertainty is done through a robustness test by applying a Placquett-Burman design, investigating six parameters influencing the simultaneous chromatographic assay of five water-soluble vitamins. The estimated effects of the variation of each parameter are translated into standard uncertainty value at each concentration level. The values obtained of the relative uncertainty do not exceed the acceptance limit of 5%, showing that the procedure development was well done. In addition, a statistical comparison conducted to compare standard uncertainty after the development stage and those of the validation step indicates that the estimated uncertainty are equivalent. The results obtained show clearly the performance and capacity of the chromatographic method to simultaneously assay the five vitamins and suitability for use in routine application. Copyright © 2015 Académie Nationale de Pharmacie. Published by Elsevier Masson SAS. All rights reserved.

  12. A rapid analysis of plasma/serum ethylene and propylene glycol by headspace gas chromatography

    National Research Council Canada - National Science Library

    Ehlers, Alexandra; Morris, Cory; Krasowski, Matthew D

    2013-01-01

    A rapid headspace-gas chromatography (HS-GC) method was developed for the analysis of ethylene glycol and propylene glycol in plasma and serum specimens using 1,3-propanediol as the internal standard...

  13. Comments on “innovative method for carbon dioxide determination in human postmortem cardiac gas samples using headspace-gas chromatography–mass spectrometry and stable labeled isotope as internal standard” by Varlet et al

    Energy Technology Data Exchange (ETDEWEB)

    Saffaj, T., E-mail: taoufiq.saffaj@usmba.ac.ma [Centre Universitaire Régional d’Interface, Université Sidi Mohamed Ben Abdellah, BP 2626, route d’Imouzzer, Fes Morocco (Morocco); Laboratoire de Chimie Organique Appliquée, Faculté des Sciences et Techniques, BP 2202, route d’Imouzzer, Fes Morocco (Morocco); Ihssane, B. [Laboratoire de Chimie Organique Appliquée, Faculté des Sciences et Techniques, BP 2202, route d’Imouzzer, Fes Morocco (Morocco)

    2014-01-31

    Graphical abstract: -- Highlights: •We comment on the validation results of the method for CO{sub 2} analysis in cardiac samples. •We demonstrate that the total error of the method exceeds the acceptance limits. •We show that the method is not valid according to the new SFSTP guideline. -- Abstract: Varlet et al. recently proposed a headspace-gas chromatography–mass spectrometry (HS-GC–MS) method applicable for the routine determination of CO{sub 2} in gaseous biologic matrices. This developed bioanalytical method was fully validated according to the SFSTP 1997 guidelines using the accuracy profile as a graphical decision-making tool.In this letter, we discuss the validity of HS-GC–MS method based on the newest SFSTP guideline. In particular, we demonstrate by the estimation of the β-expectation tolerance interval that the error total exceeds the acceptance limits (30%) for the second concentration level (0.5 μmol mL{sup −1} vial HS). Furthermore, we show through the risk profile that the probability to have future results inside the ±30% acceptance limits is smaller than 95%.

  14. Determination of marker pteridins and biopterin reduced forms, tetrahydrobiopterin and dihydrobiopterin, in human urine, using a post-column photoinduced fluorescence liquid chromatographic derivatization method

    Energy Technology Data Exchange (ETDEWEB)

    Canada-Canada, Florentina, E-mail: floricanada@gmail.com [Department of Analytical Chemistry, University of Extremadura, 06071 Badajoz (Spain); Espinosa-Mansilla, Anunciacion; Munoz de la Pena, Arsenio; Mancha de Llanos, Alicia [Department of Analytical Chemistry, University of Extremadura, 06071 Badajoz (Spain)

    2009-08-19

    A liquid chromatographic method for the simultaneous analysis of marker pteridins and biopterin reduced forms, in urine samples is proposed. A Zorbax Eclipse XDB-C18 column was used for the chromatographic separation, using a 98/2 (v/v), citrate buffer (pH 5.5)-acetonitrile mobile phase, in isocratic mode. A post-column photoderivatization was carried out with an on-line photoreactor, located between a diode array detector (DAD) and a fast scanning fluorescence detector (FSFD). Neopterin (NEO), biopterin (BIO), pterin (PT) and dihydrobiopterin (BH2) were determined by measuring native fluorescence, using the photoreactor in OFF-mode, and tetrahydrobiopterin (BH4) was determined by measuring of the induced fluorescence of the generated photoproducts, using the photoreactor in ON-mode. In addition, Creatinine (CREA), as a reference of metabolites excrection in urine, was simultaneously determined using the DAD detector. Detection limits were 0.2, 13.0, 0.3, 0.3 and 3.5 ng mL{sup -1}, for NEO, BH2, BIO, PT and BH4, respectively, and 0.4 {mu}g mL{sup -1} for CREA. Ratio values for NEO/CREA, PT/CREA, BH4/CREA, BH2/CREA, NEO/BIO and BIO{sub total}/CREA, in urine samples, of healthy children and adults, phenylketonuric children and infected mononucleosis children, are reported. A comparative study, about the mean values obtained for each of the compounds, by the present procedure and by the classical iodine oxidation method (Fukushimas method), has been performed, in urine samples belonging to healthy volunteers. The values obtained were BH4/CREA: 0.41, BH2/CREA: 0.31 and BIO{sub total}/CREA: 0.73, by the proposed method, and BH4/CREA: 0.35, BH2/CREA: 0.20 and BIO{sub total}/CREA: 0.48, by iodine oxidation method.

  15. On the Development of a Very Rapid Gas Chromatographic Method for the Analysis of High Molecular Weight Hydrocarbons in Cigarette Smoke

    Directory of Open Access Journals (Sweden)

    Coleman III WM

    2014-12-01

    Full Text Available A very rapid, flash-gas chromatographic (GC, quantitative method for the analysis of high molecular weight saturated hydrocarbons in cigarette smoke has been developed. The method was fast, accurate and precise. Sample turn around times were approximately six minutes, with an accompanying average percent relative standard deviation (%RSD of less than 10%. Four linear saturated hydrocarbons with 27, 29, 31 and 33 carbon atoms were quantitated in an array of reference cigarettes ranging in “tar” deliveries from approximately 2 to approximately 20 mg. By use of a cyclohexane extraction of cigarette smoke captured on Cambridge filter pads, the extraction efficiency was determined to be greater than 95% for each hydrocarbon. The approach represents a significant advance over current analytical procedures that require, on average, greater than 30-min sample turn around times.

  16. A validated stability-indicating liquid chromatographic method for determination of process related impurities and degradation behavior of Irbesartan in solid oral dosage

    Directory of Open Access Journals (Sweden)

    Nishant Goswami

    2014-01-01

    Full Text Available The present work describes the development and validation of a stability-indicating RP-HPLC method for the estimation of degradation and process related impurities of Irbesartan, namely Impurity-1, Impurity-2, Impurity-3 and Impurity-4. The developed LC method was validated with respect to specificity, limit of detection and quantification, linearity, precision, accuracy and robustness. The chromatographic separation was achieved on Hypersil Octadecylsilyl (4.6 mm Χ 150 mm, 3 ΅m column by using mobile phase containing a gradient mixture of solvent A (0.55% v/v ortho-phosphoric acid, pH adjusted to 3.2 with triethyl amine and B (95:5 v/v mixture of acetonitrile and solvent A at a flow rate of 1.2 mL/min. The detection was carried out at a wavelength of 220 nm. During method validation parameter such as precision, linearity, accuracy, specificity, limit of detection and quantification were evaluated, which remained within acceptable limits. HPLC analytical method is linear, accurate, precise, robust and specific, being able to separate the main drug from its degradation products. The degradation products were well-resolved from the main peak and its impurities, thus proving the stability-indicating power of the method. The method is stability-indicating in nature and can be used for routine analysis of production samples and to check the stability of the Irbesartan HCl tablets.

  17. Development and Validation of a Specific Stability Indicating High Performance Liquid Chromatographic Methods for Related Compounds and Assay of Solifenacin Succinate

    Directory of Open Access Journals (Sweden)

    B. V. Rami Reddy

    2013-01-01

    Full Text Available Gradient, reverse phase liquid chromatographic methods were developed separately for the related compounds and solifenacin succinate, an active pharmaceutical ingredient used for the treatment of overactive bladder. Gradient LC method was employed for related compounds. The mobile phase-A contains a 0.01 M phosphate buffer pH: 3.5±0.05 with orthophosphoric acid (88% and mobile phase-B contains a mixture of acetonitrile and water in the ratio of 90 : 10(v/v. The flow rate was 1.0 mL/minute, column temperature was kept at 35°C, and detection was monitored at 220 nm. In the developed HPLC method the resolution between solifenacin succinate and its closely eluting impurity, that is, solifenacin N-oxide was found to be greater than 3.0. The drug was subjected to stress conditions such as hydrolysis, oxidation, photolysis, and thermal degradation. Considerable degradation was found to occur in only oxidative stress condition. Degradation product formed during oxidative stress condition was found to be impurity-C and it can be identified by LC-MS. The stress samples were assayed against a qualified reference standard and the mass balance was found close to 99.5%. The developed RP-LC method was validated as per ICH guidelines. We also developed LC-MS/MS method for determination and identification of these impurities in solifenacin succinate.

  18. A rapid analysis of plasma/serum ethylene and propylene glycol by headspace gas chromatography.

    Science.gov (United States)

    Ehlers, Alexandra; Morris, Cory; Krasowski, Matthew D

    2013-12-01

    A rapid headspace-gas chromatography (HS-GC) method was developed for the analysis of ethylene glycol and propylene glycol in plasma and serum specimens using 1,3-propanediol as the internal standard. The method employed a single-step derivitization using phenylboronic acid, was linear to 200 mg/dL and had a lower limit of quantitation of 1 mg/dL suitable for clinical analyses. The analytical method described allows for laboratories with HS-GC instrumentation to analyze ethanol, methanol, isopropanol, ethylene glycol, and propylene glycol on a single instrument with rapid switch-over from alcohols to glycols analysis. In addition to the novel HS-GC method, a retrospective analysis of patient specimens containing ethylene glycol and propylene glycol was also described. A total of 36 patients ingested ethylene glycol, including 3 patients who presented with two separate admissions for ethylene glycol toxicity. Laboratory studies on presentation to hospital for these patients showed both osmolal and anion gap in 13 patients, osmolal but not anion gap in 13 patients, anion but not osmolal gap in 8 patients, and 1 patient with neither an osmolal nor anion gap. Acidosis on arterial blood gas was present in 13 cases. Only one fatality was seen; this was a patient with initial serum ethylene glycol concentration of 1282 mg/dL who died on third day of hospitalization. Propylene glycol was common in patients being managed for toxic ingestions, and was often attributed to iatrogenic administration of propylene glycol-containing medications such as activated charcoal and intravenous lorazepam. In six patients, propylene glycol contributed to an abnormally high osmolal gap. The common presence of propylene glycol in hospitalized patients emphasizes the importance of being able to identify both ethylene glycol and propylene glycol by chromatographic methods.

  19. Validation of a high-performance liquid chromatographic method with UV detection for the determination of ethopabate residues in poultry liver.

    Science.gov (United States)

    Granja, Rodrigo H M M; Niño, Alfredo M Montes; Zucchetti, Roberto A M; Niño, Rosario E Montes; Salerno, Alessandro G

    2008-01-01

    Ethopabate is frequently used in the prophylaxis and treatment of coccidiosis in poultry. Residues of this drug in food present a potential risk to consumers. A simple, rapid, and sensitive column high-performance liquid chromatographic (HPLC) method with UV detection for determination of ethopabate in poultry liver is presented. The drug is extracted with acetonitrile. After evaporation, the residue is dissolved with an acetone-hexane mixture and cleaned up by solid-phase extraction using Florisil columns. The analyte is then eluted with methanol. LC analysis is carried out on a C18 5 microm Gemini column, 15 cm x 4.6 mm. Ethopabate is quantified by means of UV detection at 270 nm. Parameters such as decision limit, detection capability, precision, recovery, ruggedness, and measurement uncertainty were calculated according to method validation guidelines provided in 2002/657/EC and ISO/IEC 17025:2005. Decision limit and detection capability were determined to be 2 and 3 microg/kg, respectively. Average recoveries from poultry samples fortified with 10, 15, and 20 microg/kg levels of ethopabate were 100-105%. A complete statistical analysis was performed on the results obtained, including an estimation of the method uncertainty. The method is to be implemented into Brazil's residue monitoring and control program for ethopabate.

  20. A bridging study for oxytetracycline in the edible fillet of rainbow trout: Analysis by a liquid chromatographic method and the official microbial inhibition assay

    Science.gov (United States)

    Stehly, G.R.; Gingerich, W.H.; Kiessling, C.R.; Cutting, J.H.

    1999-01-01

    Oxytetracycline (OTC) is a drug approved by the U.S. Food and Drug Administration (FDA) to control certain diseases in salmonids and catfish. OTC is also a likely control agent for diseases of other fish species and for other diseases of salmonids and catfish not currently on the label. One requirement for FDA to extend and expand the approval of this antibacterial agent to other fish species is residue depletion studies. The current regulatory method for OTC in fish tissue, based on microbial inhibition, lacks sensitivity and specificity. To conduct residue depletion studies for OTC in fish with a liquid chromatographic method, a bridging study was required to determine its relationship with the official microbial inhibition assay. Triplicate samples of rainbow trout fillet tissue fortified with OTC at 0.3, 0.6, 1.2, 2.4, 4.8, and 9.6 ppm and fillet tissue with incurred OTC at approximately 0.75, 1.5, and 3.75 ppm were analyzed by high-performance liquid chromatography (HPLC) and the microbial inhibition assay. The results indicated that the 2 methods are essentially identical in the tested range, with mean coefficients of variation of 1.05% for the HPLC method and 3.94% for the microbial inhibition assay.

  1. Quantification of Neural Ethanol and Acetaldehyde Using Headspace GC-MS.

    Science.gov (United States)

    Heit, Claire; Eriksson, Peter; Thompson, David C; Charkoftaki, Georgia; Fritz, Kristofer S; Vasiliou, Vasilis

    2016-09-01

    There is controversy regarding the active agent responsible for alcohol addiction. The theory that ethanol (EtOH) itself was the agent in alcohol drinking behavior was widely accepted until acetaldehyde (AcH) was found in the brain. The importance of AcH formation in the brain is still subject to speculation due to the lack of a method to accurately assay the AcH levels directly. A highly sensitive gas chromatography mass spectrometry (GC-MS) method to reliably determine AcH concentration with certainty is needed to address whether neural AcH is indeed responsible for increased alcohol consumption. A headspace gas chromatograph coupled to selected-ion monitoring MS was utilized to develop a quantitative assay for AcH and EtOH. Our GC-MS approach was carried out using a Bruker Scion 436-GC SQ MS. Our approach yields limits of detection of AcH in the nanomolar range and limits of quantification in the low micromolar range. Our linear calibration includes 5 concentrations with a least-square regression greater than 0.99 for both AcH and EtOH. Tissue analyses using this method revealed the capacity to quantify EtOH and AcH in blood, brain, and liver tissue from mice. By allowing quantification of very low concentrations, this method may be used to examine the formation of EtOH metabolites, specifically AcH, in murine brain tissue in alcohol research. Copyright © 2016 by the Research Society on Alcoholism.

  2. One step ultrasound extraction and pruification method for the gas chromatographic analysis of hydrocarbons from marine sediments. Application to the monitoring of Italian coasts

    Energy Technology Data Exchange (ETDEWEB)

    Pietroletti, Marco; Mattiello, Serena; Moscato, Francesca; Oteri, Federico; Mecozzi, Mauro [ISPRA, Rome (Italy). Lab. of Chemometrics and Environmental Applications

    2012-09-15

    In this study, we describe the development of an ultrasound-assisted method for the simultaneous extraction and purification of hydrocarbons from marine sediments and then its application to the gas chromatographic analysis for the estimation of the biogenic anthropogenic and petrogenic sources of hydrocarbons present in marine sediments. The extraction of hydrocarbons and their simultaneous purification from other organic compounds present in sediments was performed by sonication of a three phase system consisting of sediment, hexane and a HCl medium at pH 2. This method allowed accurate recoveries of the hydrocarbon content in samples. In the following GC-FID analysis, we examined the hydrocarbon distribution in four different areas of the Italian seas determining the pristane to phytane ratio, the total odd n-alkanes to even n-alkanes ratio (carbon preference index), the low molecular weight to high molecular weight ratio, perylene content and the presence of the so called unresolved complex mixture; according to recent studies, these parameters support the identification of the biogenic, anthropogenic and petrogenic hydrocarbon sources present in environmental samples. GC chromatograms were then re-examined by means of two different statistical multivariate methods: two-dimensional mapping (2DMAP) and independent component analysis (ICA). 2DMAP showed the presence of a significant heterogeneity in the hydrocarbon composition of different areas and within samples of a same area. ICA confirmed the general heterogeneity evidenced by 2DMAP allowing in addition to characterise the hydrocarbon composition of one of the investigated areas. (orig.)

  3. Development and validation of a stability-indicating gas chromatographic method for quality control of residual solvents in blonanserin: a novel atypical antipsychotic agent.

    Science.gov (United States)

    Peng, Ming; Liu, Jin; Lu, Dan; Yang, Yong-Jian

    2012-09-01

    Blonanserin is a novel atypical antipsychotic agent for the treatment of schizophrenia. Ethyl alcohol, isopropyl alcohol and toluene are utilized in the synthesis route of this bulk drug. A new validated gas chromatographic (GC) method for the simultaneous determination of residual solvents in blonanserin is described in this paper. Blonanserin was dissolved in N, N-dimethylformamide to make a sample solution that was directly injected into a DB-624 column. A postrun oven temperature at 240°C for approximately 2 h after the analysis cycle was performed to wash out blonanserin residue in the GC column. Quantitation was performed by external standard analyses and the validation was carried out according to International Conference on Harmonization validation guidelines Q2A and Q2B. The method was shown to be specific (no interference in the blank solution), linear (correlation coefficients ≥0.99998, n = 10), accurate (average recoveries between 94.1 and 101.7%), precise (intra-day and inter-day precision ≤2.6%), sensitive (limit of detection ≤0.2 ng, and limit of quantitation ≤0.7 ng), robust (small variations of carrier gas flow, initial oven temperature, temperature ramping rate, injector and detector temperatures did not significantly affect the system suitability test parameters and peak areas) and stable (reference standard and sample solutions were stable over 48 h). This extensively validated method is ready to be used for the quality control of blonanserin.

  4. Determination of Lactones in Wines by Headspace Solid-Phase Microextraction and Gas Chromatography Coupled with Mass Spectrometry

    Science.gov (United States)

    Pérez-Olivero, S. J.; Pérez-Pont, M. L.; Conde, J. E.; Pérez-Trujillo, J. P.

    2014-01-01

    Application of headspace solid-phase microextraction (HS-SPME) coupled with high-resolution gas chromatographic (HRGC) analysis was studied for determining lactones in wines. Six different SPME fibers were tested, and the influence of different factors such as temperature and time of desorption, ionic strength, time of extraction, content of sugar, ethanol, tannins and anthocyanins, and pH and influence of SO2 were studied. The proposed HS-SPME-GC method is an appropriate technique for the quantitative analysis of γ-butyrolactone, γ-hexalactone, trans-whiskey lactone, γ-octalactone, cis-whiskey lactone, γ-nonalactone, γ-decalactone, δ-decalactone, and γ-undecalactone in wines. Method reproducibility and repeatability ranged between 0.6 and 5.2% for all compounds. Detection limit for γ-butyrolactone was 0.17 mg/L and a few μg/L for the rest of the compounds. The optimized method has been applied to several wine samples. PMID:24782943

  5. Determination of Lactones in Wines by Headspace Solid-Phase Microextraction and Gas Chromatography Coupled with Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    S. J. Pérez-Olivero

    2014-01-01

    Full Text Available Application of headspace solid-phase microextraction (HS-SPME coupled with high-resolution gas chromatographic (HRGC analysis was studied for determining lactones in wines. Six different SPME fibers were tested, and the influence of different factors such as temperature and time of desorption, ionic strength, time of extraction, content of sugar, ethanol, tannins and anthocyanins, and pH and influence of SO2 were studied. The proposed HS-SPME-GC method is an appropriate technique for the quantitative analysis of γ-butyrolactone, γ-hexalactone, trans-whiskey lactone, γ-octalactone, cis-whiskey lactone, γ-nonalactone, γ-decalactone, δ-decalactone, and γ-undecalactone in wines. Method reproducibility and repeatability ranged between 0.6 and 5.2% for all compounds. Detection limit for γ-butyrolactone was 0.17 mg/L and a few μg/L for the rest of the compounds. The optimized method has been applied to several wine samples.

  6. Validation of high performance liquid chromatographic and spectrophotometric methods for the determination of the antiparkinson agent pramipexole dihydrochloride monohydrate in pharmaceutical products

    Directory of Open Access Journals (Sweden)

    Serpil Sevim

    2015-12-01

    Full Text Available abstract The antiparkinson agent pramipexole dihydrochloride monohydrate was quantified in pharmaceutical products by high performance liquid chromatography (HPLC and derivative spectrophotometry. The first method was based on HPLC using tamsulosin HCl as an internal standard. In this method, chromatographic separation was achieved using a LiChrospher 60 RP column at 25°C, with a flow rate of 1.0 mL/min at 263 nm. The eluent comprised 0.01 mol/L ammonium acetate (pH 4.4 and acetonitrile (35:65 by volume. The linearity range was found to be 10.0-30.0 µg/mL with a mean recovery of 100.5 ± 1.10. The limit of detection (8 ng/mL and limit of quantification (50 ng/mL were calculated. In the second method, the first derivative spectrophotometric technique for the determination of pramipexole dihydrochloride monohydrate was performed by measuring the amplitude at 249 and 280 nm. In the first derivative technique, the absorbance and concentration plot was rectilinear over the 5.0-35.0 µg/mL range with a lower detection limit of 1.5 ng/mL and quantification limit of 4.5 ng/mL. The typical excipients included in the pharmaceutical product do not interfere with the selectivity of either method. The developed methods were validated for robustness, selectivity, specificity, linearity, precision, and accuracy as per the ICH and FDA guidelines (ICH Q2B, 1996; FDA,2000. In conclusion, the developed methods were successful in determining the quantity of the antiparkinson agent pramipexole dihydrochloride monohydrate in pharmaceutical products. The RSD values for the pharmaceutical product used in this study were found to be 0.97% for the HPLC method and 0.00% for the first derivative spectrophotometric method.

  7. Synthesis of chromatographic standards and establishment of a method for the quantification of the fatty ester composition of biodiesel from babassu oil; Sintese de padroes cromatograficos e estabelecimento de metodo para dosagem da composicao de esteres de acidos graxos presentes no biodiesel a partir do oleo de babacu

    Energy Technology Data Exchange (ETDEWEB)

    Urioste, Daniele; Castro, Matheus B.A.; Biaggio, Francisco C.; Castro, Heizir F. de [Universidade de Sao Paulo (USP), Lorena, SP (Brazil). Escola de Engenharia]. E-mail: heizir@dequi.eel.usp.br

    2008-07-01

    Several alkyl esters were synthesized, purified, characterized by {sup 1}H NMR and employed as standards for establishing chromatographic methods to monitor their formation in the synthesis of biodiesel. The efficiency of the chromatographic methods was confirmed with the products of enzymatic transesterification of babassu oil with different alcohols (C{sub 2} to C{sub 4}), using Lipozyme as catalyst. (author)

  8. Chaotropic salts in liquid chromatographic method development for the determination of pramipexole and its impurities following quality-by-design principles.

    Science.gov (United States)

    Vemić, Ana; Rakić, Tijana; Malenović, Anđelija; Medenica, Mirjana

    2015-01-01

    The aim of this paper is to present a development of liquid chromatographic method when chaotropic salts are used as mobile phase additives following the QbD principles. The effect of critical process parameters (column chemistry, salt nature and concentration, acetonitrile content and column temperature) on the critical quality attributes (retention of the first and last eluting peak and separation of the critical peak pairs) was studied applying the design of experiments-design space methodology (DoE-DS). D-optimal design is chosen in order to simultaneously examine both categorical and numerical factors in minimal number of experiments. Two ways for the achievement of quality assurance were performed and compared. Namely, the uncertainty originating from the models was assessed by Monte Carlo simulations propagating the error equal to the variance of the model residuals and propagating the error originating from the model coefficients' calculation. The baseline separation of pramipexole and its five impurities is achieved fulfilling all the required criteria while the method validation proved its reliability. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Development and validation of a simple thin-layer chromatographic method for the analysis of p-chlorophenol in treated wastewater

    Directory of Open Access Journals (Sweden)

    Tešić Živoslav

    2012-01-01

    Full Text Available A thin-layer chromatographic method with densitometric detection was established for quantification of p-chlorophenol in waste water. Degradation efficiency of p-chlorophenol was monitored after each treatment of the wastewater samples. Degradation of p-chlorophenol was performed with advanced oxidation processes (AOPs, using UV, H2O2/UV, O3/H2O2/UV, O3 and O3/UV. Developed TLC procedure has been found to be simple, rapid and precise. The method was characterized by high sensitivity (limit of detection was 11 ng per band and limit of quantification 35 ng per band, linear range (from 75 to 500 ng per band, r = 0.9965, and high precision, accuracy (mean percentage recovery 98.6%, and specificity. Additionally, the efficiency of degradation was monitored using HPLC giving comparable results with RP TLC measurements. [Acknowledgement. This work was performed within the framework of the research project No. 172017 supported by the Ministry of Education and Science of Serbia.

  10. Comparing different gas chromatographic methods for the quantification of bisphenol A (BPA) trace levels in paper and cardboard products from the market.

    Science.gov (United States)

    Jurek, A; Leitner, E

    2015-01-01

    Bisphenol A (BPA; 4,4'-(propane-2,2-diyl)diphenol), a suspected endocrine disruptor with weak estrogenic activity, is used in a variety of consumer products, including paper and cardboard products used as food contact materials. The present study compared four different gas chromatographic methods for the analysis of BPA in paper and cardboard food packages. Eighteen different food packages were extracted and BPA was determined using two different derivatisation reactions--trimethylsilylation with N,O-bis(trimethylsilyl) trifluoroacetamide (BSTFA) and halide alkylation with pentafluorobenzoyl chloride (PFBOCl)--and four different separation and detection techniques. The BSTFA derivatives were quantified with (1) GC-MS in single-ion monitoring (SIM) mode with electron ionisation (EI-GC-MS) and (2) GC-MS/MS in multiple reaction monitoring (MRM) mode using electron ionisation (EI-GC-MS/MS); while the PFBOCl derivatives were quantified with (3) GC-MS using electron ionisation (EI-GC-MS) as well as (4) GC-MS with negative chemical ionisation (NCI-GC-MS). All developed methods showed good linearity (R(2) > 0.9938), precision (CV food products was calculated for all tested paper and cardboard samples, assuming a 'worst case' scenario of 100% migration.

  11. A rapid high-performance liquid chromatographic method for the simultaneous quantitation of aspirin, salicylic acid, and caffeine in effervescent tablets.

    Science.gov (United States)

    Sawyer, MaryJean; Kumar, Vimal

    2003-09-01

    A rapid reversed-phase high-performance liquid chromatographic procedure is developed and validated for the simultaneous quantitation of aspirin, salicylic acid, and caffeine extracted from an effervescent tablet. The method uses a Hypersil C18 column (5 micro m, 15 cm x 4.6 mm) for an isocratic elution in a water-methanol-acetic acid mobile phase at a wavelength of 275 nm. The tablets' buffering effects and acid neutralizing capacity require an extraction solvent of methanol-formic acid. The range of linearity for aspirin is 0.5-1.25 mg/mL, caffeine 0.065-0.195 mg/mL, and salicylic acid 0.4-6.0% of aspirin. The overall recovery is 100.2%, 100.7%, and 99.2% for aspirin, caffeine, and salicylic acid, respectively. Under the conditions of the method, aspirin, caffeine, and salicylic acid are adequately resolved with proper peak symmetry in less than 7 min.

  12. Development and validation of a High Performance Liquid Chromatographic method for determination of etoposide in biodegradable polymeric implants

    Directory of Open Access Journals (Sweden)

    Ana Gabriela Reis Solano

    2012-01-01

    Full Text Available A method using HPLC-UV was developed and validated for the determination of etoposide incorporated into polycaprolactone implants. The method was carried out in isocratic mode using a C18 column (250 x 4.6 mm; 5 µm, at 25 ºC, with acetonitrile and acetic acid 4% (70:30 as mobile phase, a flow rate of 2 mL/min, and UV detection at 285 nm. The method was linear (r² > 0.99 over the range of 5 to 65 µg/mL, precise (RSD < 5%, accurate (recovery of 98.7%, robust, selective regarding excipient of the sample, and had a quantitation limit equal to 1.76 µg/mL. The validated method can be successfully employed for routine quality control analyses.

  13. A new gas chromatographic method for the determination of succinic acid and other di-basic acids in tissue

    National Research Council Canada - National Science Library

    Miyahara, S; Tabatam, Y

    1965-01-01

    The authors have devised a method whereby succinic acid and other di-basic acids can be determined through gas chromatography, by converting the succinic acid contained in the tissue and other acids...

  14. Stability indicating high performance thin-layer chromatographic method for simultaneous estimation of pantoprazole sodium and itopride hydrochloride in combined dosage form

    Directory of Open Access Journals (Sweden)

    Deepak Bageshwar

    2011-11-01

    Full Text Available A specific, precise and stability indicating high-performance thin-layer chromatographic method for simultaneous estimation of pantoprazole sodium and itopride hydrochloride in pharmaceutical formulations was developed and validated. The method employed TLC aluminium plates precoated with silica gel 60F254 as the stationary phase. The solvent system consisted of methanol:water:ammonium acetate; 4.0:1.0:0.5 (v/v/v. This system was found to give compact and dense spots for both itopride hydrochloride (Rf value of 0.55±0.02 and pantoprazole sodium (Rf value of 0.85±0.04. Densitometric analysis of both drugs was carried out in the reflectance–absorbance mode at 289 nm. The linear regression analysis data for the calibration plots showed a good linear relationship with R2=0.9988±0.0012 in the concentration range of 100–400 ng for pantoprazole sodium. Also, the linear regression analysis data for the calibration plots showed a good linear relationship with R2=0.9990±0.0008 in the concentration range of 200–1200 ng for itopride hydrochloride. The method was validated for specificity, precision, robustness and recovery. Statistical analysis proves that the method is repeatable and selective for the estimation of both the said drugs. As the method could effectively separate the drug from its degradation products, it can be employed as a stability indicating method. Keywords: Gastroesophageal reflux disease (GERD, Itopride hydrochloride, Pantoprazole sodium, High performance thin layer chromatography (HPTLC, Stability indicating, Forced degradation

  15. Determination of polycyclic aromatic hydrocarbons (PAHs). gas chromatographic method; Determinazione degli idrocarburi policiclici aromatici (IPA). Metodo gascaromatografico

    Energy Technology Data Exchange (ETDEWEB)

    Menichini, E.; Viviano, G. [Istituto Superiore di Sanita`, Rome (Italy). Lab. di Igiene Ambientale

    1997-12-01

    The method enables the determination of 4- to 6- ring PAHs and particularly of carcinogenic PAHs regulated in Italy. This revision is based on the results of a national collaborative study. Sample extract, obtained by a method described in a previous report (Rapporto ISTISAN: 90/33) is cleaned up by thin layer chromatography and analysed by gas chromatography; identification is confirmed by mass spectrometry. An intralaboratory quality control program is described.

  16. Chromatographic hydrogen isotope separation

    Science.gov (United States)

    Aldridge, Frederick T.

    1981-01-01

    Intermetallic compounds with the CaCu.sub.5 type of crystal structure, particularly LaNiCo.sub.4 and CaNi.sub.5, exhibit high separation factors and fast equilibrium times and therefore are useful for packing a chromatographic hydrogen isotope separation colum. The addition of an inert metal to dilute the hydride improves performance of the column. A large scale mutli-stage chromatographic separation process run as a secondary process off a hydrogen feedstream from an industrial plant which uses large volumes of hydrogen can produce large quantities of heavy water at an effective cost for use in heavy water reactors.

  17. Micellar liquid chromatographic method for the simultaneous determination of Levofloxacin and Ambroxol in combined tablets: Application to biological fluids

    Science.gov (United States)

    2013-01-01

    Background Levofloxacin hemihydrate (LEV) and ambroxol HCl (AMB) are available for the treatment of upper and lower respiratory tract infections. A survey of the literature reveals that two reversed phase HPLC methods were e reported for the simultaneous determination of LEV and AMB in pharmaceutical preparations. However the reported methods suffers from the low sensitivity, no application of the method in the combined tablets and no application to biological fluids. Also the toxic effects of the used solvents which are harmful to human beings. For this reason, our target was to develop a simple sensitive, less hazardous micellar HPLC method for the simultaneous determination of LEV and AMB in their combined dosage forms and plasma. Results The method showed good linearity over the ranges of 1–44 μg/mL and 1–20 μg/mL with limits of detection 0.26 and 0.07 μg/mL and limits of quantification 0.80 and 0.20 μg/mL for LEV and AMB, respectively. The method was further extended to the determination of LEV in spiked human plasma with mean percentage recoveries of 100.10% ± 1.14 as well as determination of LEV in real human plasma without prior extraction. Statistical evaluation of the data was performed according to ICH Guidelines. Conclusion The suggested method was successfully applied for the simultaneous analysis of the studied drugs in their co-formulated tablets and human plasma. The mean percentage recoveries in combined tablets were 100.20 ± 1.64 and 100.72 ± 1.11 for LEV and AMB, respectively and 100.10 ± 1.14 for LEV in spiked human plasma. Statistical comparison of the results with those of the comparison method revealed good agreement and proved that there were no significant difference in the accuracy and precision between the two methods respectively. PMID:24079576

  18. Interlaboratory study of a multiresidue gas chromatographic method for determination of organochlorine and pyrethroid pesticides and polychlorobiphenyls in milk, fish, eggs, and beef fat.

    Science.gov (United States)

    Bordet, François; Inthavong, Dary; Fremy, Jean-Marc

    2002-01-01

    An interlaboratory study was conducted to validate a gas chromatographic (GC) method for determination of 21 organochlorine pesticides, 6 pyrethroid pesticides, and 7 polychlorobiphenyl (PCB) congeners in milk, beef fat, fish, and eggs. The method was performed at low contamination levels, which represent relevant contents in food, and is an extension of the European standard (method NF-EN-1528, Parts 1-4). It enlarges the applicable scope of the reference EN method to pyrethroid pesticides and proposes the use of solid-phase extraction (SPE) as a cleanup procedure. Cryogenic extraction was made, and SPE cleanup was performed with 2 successive SPE cartridges: C18 and Florisil. After injection of the purified extract onto a GC column, residues were measured by electron capture detection. Food samples (liquid milk, beef fat, mixed fish, and mixed eggs) were prepared, tested for homogeneity, and sent to 17 laboratories in France. Test portions were spiked with 27 pesticides and 7 PCBs at levels from 26 to 45, 4 to 27, 31 to 67, and 19 to 127 ng/g into milk, eggs, fish, and fat, respectively. Based on results for spiked samples, the relative standard deviation for repeatability ranged from 1.5 to 6.8% in milk, 3 to 39% in eggs, 4.5 to 12.2% in fish, and 7 to 13% in fat. The relative standard deviation for reproducibility ranged from 33 to 50% in milk, 29 to 59% in eggs, 31 to 57% in fish, and 30 to 62% in fat. This method showed acceptable intra- and interlaboratory precision data, as corroborated by HORRAT values at low levels of pesticide and PCB contamination. The statistical evaluation of the results was performed according to the International Organization for Standardization (ISO; ISO 3534 standard) and 5725-2 Guideline.

  19. Stability-indicating reversed-phase liquid chromatographic method for simultaneous determination of atorvastatin and ezetimibe from their combination drug products.

    Science.gov (United States)

    Chaudhari, Bharat G; Patel, Natvarlal M; Shah, Paresh B; Patel, Laxman J; Patel, Vipul P

    2007-01-01

    A simple, precise, and rapid stability-indicating reversed-phase column liquid chromatographic (RP-LC) method has been developed and subsequently validated for simultaneous estimation of atorvastatin (ATV) and ezetimibe (EZE) from their combination drug product. The proposed RP-LC method utilizes a LiChrospher 100 C18, 5 microm, 250 x 4.0 mm id column at ambient temperature; the optimum mobile phase consists of acetonitrile-water-methanol (45 + 40 + 15, v/v/v) with apparent pH adjusted to 4.0 +/- 0.1; mobile phase flow rate of 1.0 mL/min; and UV detection at 250 nm. ATV, EZE, and their combination drug product were exposed to thermal, photolytic, hydrolytic, and oxidative stress conditions, and the stressed samples were analyzed by the proposed method. There were no other coeluting, interfering peaks from excipients, impurities, or degradation products due to variable stress conditions, and the method is specific for the estimation of ATV and EZE in the presence of degradation products. The response was linear over the concentration range of 1-80 microg/mL for ATV and EZE. The mean recoveries were 99.27 and 98.5% for ATV and EZE, respectively. The intermediate precision data were obtained under different experimental conditions, and the calculated value of the coefficient of variation was found to be less than the critical value. The proposed method can be useful in the quality control of bulk manufacturing and pharmaceutical dosage forms.

  20. Validated stability-indicating high performance thin layer chromatographic method for determination of Ivabradine hydrochloride in bulk and marketed formulation: An application to kinetic study

    Directory of Open Access Journals (Sweden)

    Mitesh H. Motisariya

    2013-12-01

    Full Text Available A sensitive, selective, precise and accurate stability-indicating high-performance thin layer chromatographic method for analysis of Ivabradine hydrochloride (IH an anti anginal agent, both as a bulk drug and in formulations was developed and validated according to ICH guideline. Densitometric analysis of IH was carried out in the absorbance mode at 287 nm using ethyl acetate: 0.389 M ammonium acetate in methanol (1:5, v/v as solvent system. This system was found to give compact spots for IH at an Rf value of 0.36 ± 0.01. Moreover, IH was subjected to acid and alkali hydrolysis, oxidation, accelerated humidity/temperature, wet heat treatment, and photo degradation. The drug undergoes degradation under mainly acidic and basic conditions. Also the degraded products were well resolved from the pure drug with significantly different Rf values. Linearity was found to be in the range of 1200–2800 ng/band. The LOD and LOQ for IH were 255.86 ng/band and 775.33 ng/band, respectively. “Bartlett’s test” and “Lack of fit” applied on peak area for linearity, additionally proved validity of the developed method. Good accuracy and precision were obtained as revealed from %RSD value less than 2. Similarly, no interference was observed from common excipients in tablet formulation as well as degradation product, indicating specificity of the method. As the method could effectively separate the drug from its degradation product, it can be employed as a stability-indicating one. Moreover, proposed method was also utilized to investigate the kinetics of acidic degradation process at different temperatures and first order rate constant, half-life, shelf-life and activation energy were calculated.

  1. Analysis of anti-neoplastic drug in bacterial ghost matrix, w/o/w double nanoemulsion and w/o nanoemulsion by a validated 'green' liquid chromatographic method.

    Science.gov (United States)

    Youssof, Abdullah M E; Salem-Bekhit, Mounir M; Shakeel, Faiyaz; Alanazi, Fars K; Haq, Nazrul

    2016-07-01

    The objective of the present investigation was to develop and validate a 'green' reversed phase high-performance liquid chromatography (RP-HPLC) method for rapid analysis of a cytotoxic drug 5-fluorouracil (5-FU) in bulk drug, marketed injection, water-in-oil (w/o) nanoemulsion, double water-in-oil-in-water (w/o/w) nanoemulsion and bacterial ghost (BG) matrix. The chromatography study was carried out at room temperature (25±1°C) using an HPLC system with the help of ultraviolet (UV)-visible detector. The chromatographic performance was achieved with a Nucleodur 150mm×4.6mm RP C8 column filled with 5µm filler as a static phase. The mobile phase consisted of ethyl acetate: methanol (7:3% v/v) which was delivered at a flow rate of 1.0mLmin(-1) and the drug was detected in UV mode at 254nm. The developed method was validated in terms of linearity (r(2)=0.998), accuracy (98.19-102.09%), precision (% RSD=0.58-1.17), robustness (% RSD=0.12-0.53) and sensitivity with satisfactory results. The efficiency of the method was demonstrated by the assay of the drug in marketed injection, w/o nanoemulsion, w/o/w nanoemulsion and BG with satisfactory results. The successful resolution of the drug along with its degradation products clearly established the stability-indicating nature of the proposed method. Overall, these results suggested that the proposed analytical method could be effectively applied to the routine analysis of 5-FU in bulk drug, various pharmaceutical dosage forms and BG. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Quality by Design approach in the development of hydrophilic interaction liquid chromatographic method for the analysis of iohexol and its impurities.

    Science.gov (United States)

    Jovanović, Marko; Rakić, Tijana; Tumpa, Anja; Jančić Stojanović, Biljana

    2015-06-10

    This study presents the development of hydrophilic interaction liquid chromatographic method for the analysis of iohexol, its endo-isomer and three impurities following Quality by Design (QbD) approach. The main objective of the method was to identify the conditions where adequate separation quality in minimal analysis duration could be achieved within a robust region that guarantees the stability of method performance. The relationship between critical process parameters (acetonitrile content in the mobile phase, pH of the water phase and ammonium acetate concentration in the water phase) and critical quality attributes is created applying design of experiments methodology. The defined mathematical models and Monte Carlo simulation are used to evaluate the risk of uncertainty in models prediction and incertitude in adjusting the process parameters and to identify the design space. The borders of the design space are experimentally verified and confirmed that the quality of the method is preserved in this region. Moreover, Plackett-Burman design is applied for experimental robustness testing and method is fully validated to verify the adequacy of selected optimal conditions: the analytical column ZIC HILIC (100 mm × 4.6 mm, 5 μm particle size); mobile phase consisted of acetonitrile-water phase (72 mM ammonium acetate, pH adjusted to 6.5 with glacial acetic acid) (86.7:13.3) v/v; column temperature 25 °C, mobile phase flow rate 1 mL min(-1), wavelength of detection 254 nm. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Liquid chromatographic-mass spectrometric analysis of glucuronide-conjugated anabolic steroid metabolites: method validation and interlaboratory comparison

    NARCIS (Netherlands)

    Hintikka, L.; Kuuranne, T.; Leinonen, A.; Thevis, M.; Schanzer, W.; Halket, J.; Cowan, D.; Grosse, J.; Hemmersbach, P.; Nielen, M.W.F.; Kostiainen, R.

    2008-01-01

    Liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method for simultaneous and direct detection of 12 glucuronide-conjugated anabolic androgenic steroid (AAS) metabolites in human urine is described. The compounds selected were the main metabolites detected in

  4. A validated Ultra High Pressure Liquid Chromatographic method for the characterisation of confiscated illegal slimming products containing anorexics.

    Science.gov (United States)

    Deconinck, E; Verlinde, K; Courselle, P; Beer, J O De

    2012-02-05

    A fully validated UHPLC-DAD method for the identification and quantification of pharmaceutical preparations, containing molecules frequently found in illegal slimming products (sibutramine, modafinil, ephedrine, nor-ephedrine, metformin, theophyllin, caffeine, diethylpropion and orlistat) was developed. The proposed method uses a Vision HT C18-B column (2 mm × 100 mm, 1.5 μm) with a gradient using an ammonium acetate buffer pH 5.0 as aqueous phase and acetonitrile as organic modifier. The obtained method was fully validated based on its measurement uncertainty (accuracy profile). Calibration lines for all components were linear within the studied ranges. The relative bias and the relative standard deviations for all components were respectively smaller than 3.0% and 1.5%, the β-expectation tolerance limits did not exceed the acceptance limits of 10% and the relative expanded uncertainties were smaller than 3% for all of the considered components. A UHPLC-DAD method was obtained for the identification and quantification of these kind of pharmaceutical preparations, which will significantly reduce analysis times and workload for the laboratories charged with the quality control of these preparations and which can, if necessary, be coupled to a MS-detector for a more thorough characterisation. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Simultaneous measurement of serotonin and 5-hydroxyindoleacetic acid in rat brain using a liquid chromatographic method with electrochemical detection

    NARCIS (Netherlands)

    Vries, M. de; Odink, J.

    1991-01-01

    A simple and sensitive method for the simultaneous measurement of 5-hydroxytryptamine and its main metabolite 5-hydroxyindoleacetic acid in rat brain is described. Brain tissue samples were only deproteinated and, without further extraction, were injected directly onto a high-performance liquid

  6. The portable gas chromatograph OralChroma (TM) : a method of choice to detect oral and extra-oral halitosis

    NARCIS (Netherlands)

    Tangerman, A.; Winkel, E. G.

    It is now generally accepted that the volatile sulfur compounds (VSCs) hydrogen sulfide, methyl mercaptan and dimethyl sulfide are the main contributors to halitosis when of oropharyngeal origin. Gas chromatography using a specific sulfur detector is the most appropriate method to detect halitosis

  7. The co-feature ratio, a novel method for the measurement of chromatographic and signal selectivity in LC-MS-based metabolomics

    Energy Technology Data Exchange (ETDEWEB)

    Elmsjö, Albert, E-mail: Albert.Elmsjo@farmkemi.uu.se [Department of Medicinal Chemistry, Division of Analytical Pharmaceutical Chemistry, Uppsala University (Sweden); Haglöf, Jakob; Engskog, Mikael K.R. [Department of Medicinal Chemistry, Division of Analytical Pharmaceutical Chemistry, Uppsala University (Sweden); Nestor, Marika [Department of Immunology, Genetics and Pathology, Uppsala University (Sweden); Arvidsson, Torbjörn [Department of Medicinal Chemistry, Division of Analytical Pharmaceutical Chemistry, Uppsala University (Sweden); Medical Product Agency, Uppsala (Sweden); Pettersson, Curt [Department of Medicinal Chemistry, Division of Analytical Pharmaceutical Chemistry, Uppsala University (Sweden)

    2017-03-01

    Evaluation of analytical procedures, especially in regards to measuring chromatographic and signal selectivity, is highly challenging in untargeted metabolomics. The aim of this study was to suggest a new straightforward approach for a systematic examination of chromatographic and signal selectivity in LC-MS-based metabolomics. By calculating the ratio between each feature and its co-eluting features (the co-features), a measurement of the chromatographic selectivity (i.e. extent of co-elution) as well as the signal selectivity (e.g. amount of adduct formation) of each feature could be acquired, the co-feature ratio. This approach was used to examine possible differences in chromatographic and signal selectivity present in samples exposed to three different sample preparation procedures. The capability of the co-feature ratio was evaluated both in a classical targeted setting using isotope labelled standards as well as without standards in an untargeted setting. For the targeted analysis, several metabolites showed a skewed quantitative signal due to poor chromatographic selectivity and/or poor signal selectivity. Moreover, evaluation of the untargeted approach through multivariate analysis of the co-feature ratios demonstrated the possibility to screen for metabolites displaying poor chromatographic and/or signal selectivity characteristics. We conclude that the co-feature ratio can be a useful tool in the development and evaluation of analytical procedures in LC-MS-based metabolomics investigations. Increased selectivity through proper choice of analytical procedures may decrease the false positive and false negative discovery rate and thereby increase the validity of any metabolomic investigation. - Highlights: • The co-feature ratio (CFR) is introduced. • CFR measures chromatographic and signal selectivity of a feature. • CFR can be used for evaluating experimental procedures in metabolomics. • CFR can aid in locating features with poor selectivity.

  8. Determination of aldehydes in drinking water and river water by headspace GC/negative-ion chemical-ionization MS

    National Research Council Canada - National Science Library

    Minako HADA; Masahiko TAKINO; Shigeki DAISHIMA

    2000-01-01

      A method for the analysis of 7 aldehydes in drinking water and river water was developed using an headspace sampler in combination with a GC/MS with negative-ion chemical ionization(NICI).A sample(15ml...

  9. Simultaneous determination of seven penicillins in muscle, liver and kidney tissues from cattle and pigs by a multiresidue high-performance liquid chromatographic method.

    Science.gov (United States)

    Sørensen, L K; Snor, L K; Elkaer, T; Hansen, H

    1999-11-12

    A high-performance liquid chromatographic (HPLC) method based on solid-phase extraction (SPE) was developed for determination of amoxicillin, penicillin G (benzylpenicillin), ampicillin, oxacillin, cloxacillin, nafcillin and dicloxacillin in muscle, liver and kidney tissues of pigs and cattle. The compounds were extracted in aqueous solution by precipitation of organic materials with a mixture of sulphuric acid and sodium tungstate. The extract was cleaned up by SPE on a divinylbenzene-co-N-vinylpyrrolidone polymeric sorbent. Further clean-up was performed by liquid-liquid partition with diethyl ether. The extract was derivatised with benzoic anhydride and 1,2,4-triazole mercury (II) reagent. Chromatography was performed by reversed-phase gradient HPLC on a C18 column with ultraviolet detection at 323 nm. The limits of detection estimated by a conservative model were in the range 8.9-11.1 microg/kg for amoxicillin, penicillin G, ampicillin, oxacillin, cloxacillin and nafcillin and 18.3-20.9 microg/kg for dicloxacillin. The mean recovery range was 66-77% for amoxicillin, 73-75% for penicillin G, 81-82% for ampicillin, 73-76% for oxacillin, 74-75% for cloxacillin, 66-72% for nafcillin and 58-65% for dicloxacillin.

  10. Study of the complexation of different methacrylates with cyclodextrins employing a combination of electrophoretic, chromatographic, and NMR-spectroscopic methods.

    Science.gov (United States)

    Al-Rimawi, Fuad; Pyell, Ute

    2007-03-01

    The present study describes the application of capillary electromigration techniques; CEC and micellar EKC (MEKC), and the application of spectroscopic methods; 1H NMR and 1H NOESY spectroscopy to investigate interactions between CDs (alpha-CD, statistically methylated beta-CD, hydroxypropyl-beta-CD, and 2-hydroxypropyl-gamma-CD) and different methacrylates (adamantyl, isobornyl, cyclohexyl, and phenyl methacrylate). It is shown that these methods complement each other. While CD-mediated MEKC is a rapid screening technique for comparing complex stabilities in aqueous media, 1H NMR chemical shift analysis provides quantitative data for very strong methacrylate-CD complexes and CD-mediated CEC provides quantitative data for complexes with lower complex forming constants. CD-mediated MEKC did not prove to be suitable for the calculation of complex forming constants. Reasons are discussed. 1H NOESY spectra were used to study spatial relationships between host and guest atoms.

  11. Development and validation of a high performance liquid chromatographic method for determination of cyclosporine-A from biodegradable intraocular implants

    Directory of Open Access Journals (Sweden)

    Juliana Barbosa Saliba

    2011-01-01

    Full Text Available An HPLC method was developed and validated aiming to quantify the cyclosporine-A incorporated into intraocular implants, released from them; and in direct contact with the degradation products of PLGA. The separation was carried out in isocratic mode using acetonitrile/water (70:30 as mobile phase, a C18 column at 80 ºC and UV detection at 210 nm. The method provided selectivity based on resolution among peaks. It was linear over the range of 2.5-40.0 µg/mL. The quantitation and detection limits were 0.8 and 1.2 µg/mL, respectively. The recovery was 101.8% and intra-day and inter-day precision was close to 2%.

  12. A simple and rapid chromatographic method to determine unauthorized basic colorants (rhodamine B, auramine O, and pararosaniline) in processed foods

    Science.gov (United States)

    Tatebe, Chiye; Zhong, Xining; Ohtsuki, Takashi; Kubota, Hiroki; Sato, Kyoko; Akiyama, Hiroshi

    2014-01-01

    A simple and rapid high-performance liquid chromatography (HPLC) method to determine basic colorants such as pararosaniline (PA), auramine O (AO), and rhodamine B (RB) in various processed foods was developed. Linearity of the calibration curves ranged from 0.05 to 50 μg/mL for PA and 0.05–100 μg/mL for AO and RB. The detection and quantification limits (LOD and LOQ) of the basic colorants, which were evaluated as signal-to-noise ratios of 3 for LOD and 10 for LOQ, ranged from 0.0125 to 0.05 and 0.025 to 0.125 μg/g, respectively. The recoveries and relative standard deviations of three basic colorants in six processed foods, namely, chili sauce, curry paste, gochujang (hot pepper paste), tandoori chicken (roasted chicken prepared with yogurt and spices), powder soup, and shrimp powder ranged from 70.2% to 102.8% and 0.8% to 8.0%, respectively. The intraday precision of the recovery test ranged from 1.7% to 4.5%, whereas the interday precision ranged from 3.7% to 7.7%. The reported method has been successfully applied to basic colorant determination in various processed foods such as fat-based food matrices (curry paste and tandoori chicken), chili products (gochujang and chili sauce), and protein-based products (shrimp powder and powder soup). Thin layer chromatography and liquid chromatography/mass spectrometry methods for the determination of basic colorants in processed foods were also developed for rapid analysis and identification, respectively. These methods are very useful for monitoring unauthorized basic colorants in inspection centers or quarantine laboratories in many countries. PMID:25473512

  13. A solid-phase microextraction method for the chromatographic determination of organophosphorus pesticides in fish, water, potatoes, guava and coffee

    OpenAIRE

    Capobiango,Helena L. V.; Cardeal, Zenilda L.

    2005-01-01

    This paper describes a Solid Phase Microextraction method (SPME-CG) to the determination of organophosphorus pesticides in samples of fresh-water fish, water, potatoes, guava and coffee by capillary gas chromatography with nitrogen phosphorus detector. The samples were collected from October 2002 to April 2003 in the tributaries and sub-tributaries of the Paranaiba River, which supplies the city of Patos de Minas, Minas Gerais, Brazil. The determination of the pesticides: co-ral (O,O-diethyl ...

  14. Application of Chromatographic and Electrophoretic Methods for the Analysis of Imidazolium and Pyridinium Cations as Used in Ionic Liquids

    Directory of Open Access Journals (Sweden)

    P. Stepnowski

    2006-11-01

    Full Text Available Interest in ionic liquids for their potential in different chemical processes isconstantly increasing, as they are claimed to be environmentally benign – excellent, non-volatile solvents for a wide range of applications. The wide applicability of thesecompounds also demands reliable, relatively simple and reproducible analytical techniques.These methods must be applicable not only to different technical or natural matrices but alsoto the very low concentrations that are likely to be present in biological and environmentalsystems. In this review, therefore, methods for separating and analysing imidazolium- andpyridinium-type ionic liquids in aqueous matrices using high performance liquidchromatography (HPLC and capillary electrophoresis (CE are examined. The techniquesfor identifying ionic liquids are meant primarily to track the concentrations of ionic liquidsas residues not only in products and wastes but also in biological or environmental samples.The application of hyphenated techniques in this field is intended to selectively separate thequaternary entity from other cationic and non-ionic species present in the matrix, and toenable its fine-scale quantification. Nowadays, methods developed for cation analysis arebased mostly on reversed-phase high-performance liquid chromatography, ionchromatography, ion-pair chromatography and capillary electrophoresis, where variousbuffered mobile phases are used.

  15. Automated high-performance liquid chromatographic method with precolumn reduction for the determination of ubiquinol and ubiquinone in human plasma.

    Science.gov (United States)

    Wang, Q; Lee, B L; Ong, C N

    1999-04-16

    We developed a gradient HPLC method with automated precolumn reduction for direct electrochemical detection of ubiquinol-10 (CoQ10H2) and total coenzyme Q10 (TQ10) in human plasma. The concentration of ubiquinone-10 (CoQ10) was calculated by subtraction of CoQ10H2 from TQ10. Preparation of reducing agent and precolumn reduction was performed by a programmable auto-injector. The two mobile phases used were: A, 100% of methanol containing 50 mM sodium perchlorate and 10 mM perchloric acid; and B, a mixture of ethanol and tert.-butanol (80:20, v/v). Sample preparation was simply a deproteinisation process with 10-fold ethanol. A good linear relationship was obtained for CoQ10H2 concentration from 0.1 to 3 micromol/l. The detection limit was 2.5 nmol/l with an injection volume of 20 microl. The analytical recovery and reproduciblity were generally >90%. To validate the method, 18 freshly collected plasma samples of normal healthy subjects were analysed. The mean ratio of CoQ10H2/CoQ10 was 93:7. The proposed method is sensitive, reliable and can be used for clinical investigation.

  16. Optimization, validation and application of a method for the determination of trichloroethylene in rat plasma by headspace solid-phase microextraction gas chromatography mass spectrometry.

    Science.gov (United States)

    Liu, Yongzhen; Muralidhara, Srinivasa; Bruckner, James V; Bartlett, Michael G

    2008-09-01

    Trichloroethylene (TCE) is a small halogenated compound that has been used extensively as a metal degreaser and a solvent for the past 100 years. As a result of its widespread use, TCE can be found in the groundwater of about one-third of the hazardous waste sites on the United States Environmental Protection Agency's National Priorities List. Human exposure to TCE in the environmental media is of concern because TCE has been found to be carcinogenic in laboratory animals. This paper describes the development and validation of a HS-SPME-GC/MS method for determination of TCE in rat plasma. The effects of different parameters such as sample volume, extraction and desorption conditions, fiber positions and salt addition were investigated and optimized. The method is rapid, simple, sensitive and requires a very small sample volume. The lower limit of quantitation was 0.25 ng/mL and correlation coefficient (r(2)) values for the linear range of 0.25-100 ng/mL were 0.996 or greater. The precision and accuracy for intra-day and inter-day were better than 8.0%. This validated method was successfully applied to study the toxicokinetic behavior of TCE following low levels of oral administration.

  17. A new analytical method for quantification of olive and palm oil in blends with other vegetable edible oils based on the chromatographic fingerprints from the methyl-transesterified fraction.

    Science.gov (United States)

    Jiménez-Carvelo, Ana M; González-Casado, Antonio; Cuadros-Rodríguez, Luis

    2017-03-01

    A new analytical method for the quantification of olive oil and palm oil in blends with other vegetable edible oils (canola, safflower, corn, peanut, seeds, grapeseed, linseed, sesame and soybean) using normal phase liquid chromatography, and applying chemometric tools was developed. The procedure for obtaining of chromatographic fingerprint from the methyl-transesterified fraction from each blend is described. The multivariate quantification methods used were Partial Least Square-Regression (PLS-R) and Support Vector Regression (SVR). The quantification results were evaluated by several parameters as the Root Mean Square Error of Validation (RMSEV), Mean Absolute Error of Validation (MAEV) and Median Absolute Error of Validation (MdAEV). It has to be highlighted that the new proposed analytical method, the chromatographic analysis takes only eight minutes and the results obtained showed the potential of this method and allowed quantification of mixtures of olive oil and palm oil with other vegetable oils. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. MICROSCOPIC, PHYSICOCHEMICAL AND CHROMATOGRAPHIC ...

    African Journals Online (AJOL)

    Peters

    sulphated ash 19.6%, water-soluble ash 6.8%, alcohol-soluble extractive 9.5% and water-soluble extractive 24.1%. Chromatographic fingerprints of ... chloral hydrate, mounted in dilute glycerol on a microscope slide and viewed at different ... was washed off in water and the sample mounted on a slide with glycerin.

  19. A short review of headspace extraction and ultrasonic solvent extraction for honey volatiles fingerprinting

    Directory of Open Access Journals (Sweden)

    Z. Marijanović

    2009-01-01

    Full Text Available Honey volatiles exhibit a potential role in distinguishing honeys as a function of botanical origin, but heating of honey generates artefacts such as compounds of Strecker degradation and Maillard reaction products. This short review is focused on the most recently applied methods for honey volatiles fingerprinting (without generation of thermal artefacts: headspace extraction (dynamic headspace extraction (DHE, headspace solid-phase microextraction (HS-SPME and ultrasonic solvent extraction (USE. These methods display a varying degree of selectivity and effectiveness depending upon the compounds involved and the extraction conditions. Recent developments of these methods are discussed, with application examples drawn from the literature as well from our own research. Flavour qualities of the honey are very much dependent on the volatile and semivolatile organic compounds present in both the sample matrix and the headspace aroma. Therefore the use of one single technique is not adequate for reliable honey volatiles profiling, but combined use of headspace extraction and ultrasonic solvent extraction could be a useful tool for the characterization of the honey and identification of its botanical source through typical volatile marker compounds.

  20. Determination of residues of sulfonylurea herbicides in soil by using microwave-assisted extraction and high performance liquid chromatographic method

    Directory of Open Access Journals (Sweden)

    Grahovac Nada L.

    2017-01-01

    Full Text Available A modified method for the analysis of nicosulfuron, rimsulfuron and prosulfuron was developed and validated by using microwave-assisted extraction (MAE and ultra-performance liquid chromatography with diode array detection in the ultraviolet region (HPLC-UV-DAD. The most important experimental parameters of extraction procedure and HPLC-UV-DAD technique were optimised in respect to those sulfonylurea herbicides. High recoveries of the microwave-assisted extraction were obtained by using a dichloromethane–acetonitrile mixture (2:1 volume ratio acidified with acetic acid (0.8 vol.% with the addition of urea. The mean recoveries at three spiking levels ranged from 97.47 to 98.76% for nicosulfuron, 97.88 to 99.17% for rimsulfuron and from 97.91 to 99.83% for prosulfuron. The limits of detection of nicosulfuron, rimsulfuron and prosulfuron were 0.95, 0.91 and 0.89 μg kg–1, respectively. The accuracy of the developed method was confirmed by HPLC coupled with tandem mass spectrometry parallel analyses. The developed method was used to investigate the dissipation dynamics of sulfonylurea herbicides in the real field trials in Vojvodina Province, Serbia. The obtained half-lives were 0.05, 0.23 and 0.15 days for recommended dose application of nicosulfuron, rimsulfuron and prosulfuron, respectively. Low residues and short half-life in soil suggested that the risk to sensitive rotational crops after application of those sulfonylurea herbicides is low when they are used in the appropriate dosages. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR 31072

  1. Microemulsion liquid chromatographic method for simultaneous separation and determination of six flavonoids of Apocynum venetum leaf extract.

    Science.gov (United States)

    Song, Rui juan; Zhou, Jun

    2015-07-15

    A simple, cost-effective, and efficient method was developed for the rapid simultaneous separation and determination of six flavonoids (rutin, hyperoside, quercetin-3-O-sophoroside, isoquercitrin, astragalin and quercetin) of Apocynum venetum leaf extract by reversed phase high performance liquid chromatography using a microemulsion system mixture as the mobile phase. Separations were performed on the Zorbax Extend-C18 column with UV detection at 360nm. The flow rate was 0.8mLmin(-1). The optimized microemulsion mobile phase consisted of 2.5% (v/v) n-butanol, 1.2% (v/v) of Genapol X-080, 0.5% (v/v) ethyl acetate and 95.8% (w/v) of aqueous 20mM phosphoric acid, pH adjusted to 6.0 with 0.3% triethylamine. Under the optimized conditions, the calibration curve for six flavonoids was linear in the range of 5-1000μgmL(-1) with the correlation coefficients greater than 0.9994. The intra-day and inter-day precision (RSD) were below 8.11% and the limits of detection (LOD) for the six flavonoids were 1.7-6.0μgmL(-1) (S/N=3). The microemulsion liquid chromatography (MELC) method was successfully applied to separate and determine the six flavonoids of A. venetum leaf extract. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Quantification of main bioactive metabolites from saffron (Crocus sativus) stigmas by a micellar electrokinetic chromatographic (MEKC) method.

    Science.gov (United States)

    Gonda, Sándor; Parizsa, Péter; Surányi, Gyula; Gyémánt, Gyöngyi; Vasas, Gábor

    2012-07-01

    Saffron is an expensive spice, cultivated in many regions of the world. Its chief metabolites include crocins, which are responsible for the coloring ability, safranal, which is the main essential oil constituent, and picrocrocin which is the main bitter constituent of the spice. A simple micellar capillary electrochromatographic (MEKC) method capable of quantifying all three types of main constituents was established. The pH, sodium dodecyl sulphate (SDS) content and electrolyte concentration of the background electrolyte was optimized. A simple extraction protocol was developed which can extract all metabolites of different polarity from the saffron stigmas. Optimal background electrolyte composed of 20 mM disodium phosphate, 5mM sodium tetraborate, 100 mM SDS, pH was set 9.5. Optimal extracting solvent was the background electrolyte, incubated with the sample for 60 min. The proposed method allows quantification of picrocrocin, safranal, crocetin- Di-(β-D-gentiobiosyl) ester and crocetin (β-D-glycosyl)-(β-D-gentiobiosyl) ester within 17.5 min, with limit of detection values ranging from 0.006 to 0.04 mg/ml, from a single stigma. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Analysis and stability of sucralose in a milk-based confection by a simple planar chromatographic method.

    Science.gov (United States)

    Morlock, Gertrud E; Prabha, Shashi

    2007-09-05

    Sucralose used as high potency sweetener in foods was determined in burfi, a milk-based confection produced in-house. Therefore planar chromatography was employed as a preferred method because of a reagent-free derivatization step. Sucralose was determined on HPTLC amino plates whose amino groups reacted with sucralose to fluorescent zones by just heating the plate after chromatography. Thus derivatization was simultaneously performed for 22 separations per plate, and with ease, over 300 runs can be performed within a day of labor. The within-run precision (%RSD) of sucralose determination in milk-based confection was 4.2% (n = 5), and the mean recovery 88% +/- 4.7% (n = 6). LOD via fluorescence measurement was 6 ng/band for standard solutions and 1 mg/kg for the milk-based matrix. According to European legislation, the limits for sucralose addition ranged between 10 and 3000 mg/kg for various foods and thus were fully met with this method. The fluorescence measurement at 366/>400 nm turned out to be slightly more robust and intense than the absorbance measurement at UV 254 nm. The stability of sucralose in milk-based confection was proved under the usual storage conditions at 5, 30, and 45 degrees C for up to 28 days. Potential hydrolysis products of sucralose caused by various modes of storing the confection were not observed up to 28 days.

  4. Validated high-performance liquid chromatographic method for the standardisation of Ptychopetalum olacoides Benth., Olacaceae, commercial extracts

    Directory of Open Access Journals (Sweden)

    Renata Colombo

    2010-10-01

    Full Text Available Ptychopetalum olacoides Benth., Olacaceae, popularly known as marapuama or muirapuama or miriantã, is a species native to the Amazonian region of Brazil. Extracts of the bark of the plant have been used traditionally for its stimulating and aphrodisiac properties and currently commercialised by the herbal industry as constituents in a wide range of phytomedicines. Fractionation by open column chromatography followed by preparative HPLC-UV/PAD of the stem bark and of three commercial extracts of P. olacoides allowed the isolation of three components that were common to all extracts analysed, and these were identified by NMR to be vanillic acid, protocatechuic acid and theobromine. Vanillic acid, which has been proposed as a phytochemical marker for P. olacoides, was employed as an external standard in the development and validation of a rapid qualitative and quantitative HPLC assay for the analyte. The recoveries values of the developed method were 99.02% and the LOD and LOQ values were 0.033 and 0.11 mg.L-1, respectively. The described method may be applied to the standardisation of herbs, extracts or phytomedicines commercialised as marapuama.

  5. Evaluation of Pentachlorophenol Residues in Some Hygienic Papers Prepared from Virgin and Secondary Pulp by Electron Capture Gas Chromatographic Method

    Directory of Open Access Journals (Sweden)

    Behrouz Akbari-adergani

    2016-01-01

    Full Text Available In this study, residual amount of pentachlorophenol (PCP as the most important paper preservative, which is extremely hazardous pollutant, was determined in some tissue papers and napkins. Twenty-five samples of two producing hygienic paper factories prepared from virgin and secondary pulp were analyzed for the presence of trace amount of PCP. The analytical procedure involved direct extraction of PCP from hygienic paper and its determination by gas chromatography with electron capture detection. The statistical results for the analysis of all samples revealed that there were significant differences between mean of PCP in hygienic papers prepared from virgin and secondary pulp (P<0.05. This method gave recoveries of 86-98% for hygienic paper made from virgin pulp and 79-92% for hygienic paper made from secondary pulp. The limit of detection (LOD and limit of quantification (LOQ for PCP were 6.3 and 21.0 mg/kg, respectively. The analytical method has the requisite sensitivity, accuracy, precision and specificity to assay PCP in hygienic papers. This study demonstrates a concern with exposition to PCP considering that hygienic paper is largely consumed in the society.

  6. A simple chromatographic method for determining norfloxacin and enoxacin in pharmacokinetic study assessing CYP1A2 inhibition.

    Science.gov (United States)

    Kobayashi, Toshimi; Homma, Masato; Momo, Kenji; Kobayashi, Daisuke; Kohda, Yukinao

    2011-04-01

    We developed a simple assay method for the determination of serum and urine norfloxacin and enoxacin using reversed-phase high-performance liquid chromatography and perchloric acid precipitation for sample pre-treatment. Optimized conditions can permit detection of norfloxacin and enoxacin in the same chromatogram, so either compound can be used as an internal standard for another determinant. Supernatants of the precipitated samples were analyzed by the octadecylsilyl silica-gel column under ambient temperature and an ultraviolet wavelength of 272  nm. A mobile phase solvent consisting of 20 mm sodium dihydrogenphosphate (pH 3.0) and acetonitrile (85:15, v/v) was pumped at a flow rate of 1.0 mL/min. The calibration curves for norfloxacin and enoxacin at a concentration of 62.5-1000 ng/mL for serum and 250-4000 ng/mL for urine were linear (r > 0.9997). The recoveries of norfloxacin and enoxacin from serum and urine were >94% with the coefficient of variations (CV) <5%. The CVs for intra- and inter-day assay of norfloxacin and enoxacin were <4.2 and <5.5%, respectively. This method can be applied to the pharmacokinetic study of norfloxacin and enoxacin after repeated administration to assess changes in CYP1A2 activity in healthy subjects. Copyright © 2010 John Wiley & Sons, Ltd.

  7. Gas chromatographic sulphur speciation in heavy crude oil using a modified standard D5623 method and microfluidic Deans switching.

    Science.gov (United States)

    Heshka, Nicole E; Choy, Joanne M; Chen, Jinwen

    2017-12-29

    A modification to American Society for Testing and Materials (ASTM) method D5623 is proposed to enable successful and repeatable analysis of heavy crude oil samples. A two-dimensional gas chromatography configuration was implemented, with separation of sulphur compounds occurring on two columns. A Deans switch is used to enable heart-cutting of volatile sulphur compounds onto a DB-Sulfur stationary phase, and separation occurs concurrently with the backflushing of the primary column. The use of a sulphur-selective detector increases selectivity, and 22 volatile sulphur species are quantified in less than 15min, which is almost half the time of the original ASTM method. Samples ranging from light distillation cuts to whole crudes (boiling from 100°C to >750°C) were analyzed with minimal sample preparation. The calculated limit of detection was 0.7mg/kg, repeatability was 3% relative standard deviation (RSD), and a linear range of 1-250mg/kg was obtained, with an R2 value of 0.994 or better, depending on the compound. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  8. Development and validation of a rapid chromatographic method for the analysis of flunarizine and its main production impurities

    Directory of Open Access Journals (Sweden)

    Niamh O’Connor

    2013-06-01

    Full Text Available A rapid selective method for the analysis of flunarizine and its associated impurities was developed and validated according to ICH guidelines. The separation was carried out using a Thermo Scientific Hypersil Gold C18 column (50mm×4.6mm i.d., 1.9μm particle size with a gradient mobile phase of acetonitrile–ammonium acetate–tetrabutylammoniumhydrogen sulfate buffer, at a flow rate of 1.8mL/min and UV detection at 230nm. Naturally aged samples were also tested to determine sample stability. A profile of sample and impurity breakdown was also presented. Keywords: Flunarizine, Sub 2μm column, Active pharmaceutical ingredient, HPLC

  9. Radioenzymatic assay of catecholamines in plasma after a preliminary solvent extraction compared with an analogous liquid-chromatographic method

    Energy Technology Data Exchange (ETDEWEB)

    Feoli, J.; Bijault, C.; Dehennin, L.

    1988-02-01

    Catechol-borate complexation and ion-pair formation combined with organic solvent extraction as preliminaries to radioenzymatic assay (REA) with catechol-O-methyltransferase-catalyzed methylation allows the quantification of catecholamines in plasma samples of any volume. We attained improved detection limits for 1-mL samples: 9 ng/L for norepinephrine (NE), 8 ng/L for epinephrine (E), and 11 ng/L for dopamine (DA). Precision data resemble those obtained by REA for small-volume samples. Comparison with a liquid chromatography-electrochemical detection (LCEC) technique showed the two methods to be equivalent for NE and E determinations, but DA estimations were lower by REA than by LCEC.

  10. Application of a liquid chromatographic/tandem mass spectrometric method to a urinary excretion study of rabeprazole and two of its metabolites in healthy human urine.

    Science.gov (United States)

    Lu, Chengtao; Jia, Yanyan; Song, Ying; Li, Xueqing; Sun, Yuan; Zhao, Jinyi; Wang, Shan; Shi, Lei; Wen, Aidong; Ding, Li

    2015-04-15

    To study urinary excretion properties of rabeprazole and two of its metabolites, i.e. rabeprazole thioether and desmethyl rabeprazole thioether in human urine, a sensitive, selective, accurate and precise method for the quantification of rabeprazole and two of its metabolites using a liquid chromatographic/tandem mass spectrometric method has been developed and validated. Starting with a 200 μL urine aliquot, a general sample preparation was performed using protein precipitation with methanol. Analytes were separated on a Dikma Inspire™ C18 column (150 mm × 2.1mm, 5 μm) using a mixture of methanol and aqueous 10mM ammonium acetate buffer containing 0.05% formic acid (55:45, v/v) as mobile phase. Linearity was obtained over the concentration range of 0.1446-96.38 ng/mL, 0.3198-319.8 ng/mL and 0.05160-82.53 ng/mL for rabeprazole, rabeprazole thioether, desmethyl rabeprazole thioether in human urine, respectively. The fully validated method was applied to a urine excretion study of rabeprazole sodium administered as a 30 min intravenous infusion for the first time. The calculated cumulative urinary recovery just reached 0.04745‰, 1.272‰ and 0.1631‰ of dose within 24h post-dose for rabeprazole, rabeprazole thioether, and desmethyl rabeprazole thioether, respectively, after intravenous infusion administration, indicating that rabeprazole and its two main metabolites undergo substantial non-renal elimination in healthy Chinese volunteers. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. An efficient hydrophilic interaction liquid chromatographic method for the simultaneous determination of metformin and pioglitazone using high-purity silica column.

    Science.gov (United States)

    Mohamed, Abdel-Maaboud Ismail; Mohamed, Fardous Abdel-Fattah; Ahmed, Sameh; Mohamed, Yahya Abduh Salim

    2015-08-01

    Hydrophilic interaction liquid chromatography (HILIC) provides a feasible approach to effectively separate polar compounds in complex matrices. Herein, a simple, reproducible and efficient HILIC method was developed for the simultaneous determination of pioglitazone. HCl (PIO) and metformin HCl (MET) in rabbit plasma. High-purity silica column was used for rapid and efficient separation of these co-administered drugs. The chromatographic parameters were optimized for best separation. The proposed HILIC system provides high separation efficiency with good peak shape compared to reversed phase (RP) chromatography. Additionally, a simple isocratic elution mode with a mobile phase composed of a mixture of methanol and 10mM phosphate buffer (pH 3.0) (94:6, v/v) was used and the effluent was monitored at 230nm. The method was validated in accordance with the requirements of US-FDA guidelines and was found to behave efficiently for the intended purpose. The correlation coefficient of 0.9992 was obtained in the concentration ranges of 0.5-100μgmL(-1). The limits of detection (S/N=3) and quantification (S/N=10) were 0.16 and 0.5ngmL(-1), respectively. The retention times were 3.4 and 5.0min for PIO and MET, respectively. Plasma levels were successfully determined in rabbit with satisfactory precision and accuracy. In addition, the stability tests in rabbit plasma proved reliable stability under the experimental conditions. The developed HILIC method was applied successfully to study the pharmacokinetic behaviors of the studied analytes in rabbit plasma after a single oral dose containing PIO and MET. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Development of validated stability-indicating chromatographic method for the determination of fexofenadine hydrochloride and its related impurities in pharmaceutical tablets

    Science.gov (United States)

    2011-01-01

    A simple reversed phase high performance liquid chromatographic method with diode array detector (HPLC-DAD) has been developed and subsequently validated for the determination of fexofenadine hydrochloride (FEX) and its related compounds; keto fexofenadine (Impurity A), meta isomer of fexofenadine (Impurity B), methyl ester of fexofenadine (Impurity C) in addition to the methyl ester of ketofexofenadine (Impurity D). The separation was based on the use of a Hypersil BDS C-18 analytical column (250 × 4.6 mm, i.d., 5 μm). The mobile phase consisted of a mixture of phosphate buffer containing 0.1 gm% of 1-octane sulphonic acid sodium salt monohydrate and 1% (v/v) of triethylamine, pH 2.7 and methanol (60:40, v/v). The separation was carried out at ambient temperature with a flow rate of 1.5 ml/min. Quantitation was achieved with UV detection at 215 nm using lisinopril as internal standard, with linear calibration curves at concentration ranges 0.1-50 μg/ml for FEX and its related compounds. The optimized conditions were used to develop a stability-indicating HPLC-DAD method for the quantitative determination of FEX and its related compounds in tablet dosage forms. The drugs were subjected to oxidation, hydrolysis, photolysis and heat to apply stress conditions. Complete separation was achieved for the parent compounds and all degradation products. The method was validated according to ICH guidelines in terms of accuracy, precision, robustness, limits of detection and quantitation and other aspects of analytical validation. PMID:22136482

  13. Development of a quantitative high-performance thin-layer chromatographic method for sucralose in sewage effluent, surface water, and drinking water.

    Science.gov (United States)

    Morlock, Gertrud E; Schuele, Leonard; Grashorn, Sebastian

    2011-05-13

    Sucralose, a persistent chlorinated substance used as sweetener, can already be found in waste water, and various countries focused on the release of sucralose into the aquatic environment. A quantitative high-performance thin-layer chromatography (HPTLC) method, which is orthogonal to existing methods, was developed to analyze sucralose in water. After sample preparation, separation of up to 17 samples was performed in parallel on a HPTLC plate silica gel 60 F(254) with a mixture of isopropyl acetate, methanol and water (15:3:1, v/v/v) within 15 min. Due to the weak native UV absorption of sucralose (≤200 nm), various post-chromatographic derivatization reactions were compared to selectively detect sucralose in effluent and surface water matrices. Thereby p-aminobenzoic acid reagent was discovered as a new derivatization reagent for sucralose. Compared to the latter and to β-naphthol, derivatization with aniline diphenylamine o-phosphoric acid reagent was slightly preferred and densitometry was performed by absorbance measurement at 400 nm. The limit of quantification (LOQ) of sucralose in drinking and surface water was calculated to be 100 ng/L for a given recovery rate of 80% and the extraction of a 0.5 L water sample. The sucralose content determined in four water samples obtained during an interlaboratory trial in 2008 was in good agreement to the mean laboratory values of that trial. According to the t-test, which compares the results with the target value, the means obtained by HPTLC were not significantly different from the respective means of six laboratories, analyzed by HPLC-MS/MS or HPLC-TOF-MS with the use of mostly isotopically labeled standards. The good accuracy and high sample throughput capacity proved HPTLC as a well suited method regarding quantification of sucralose in various aqueous matrices. Copyright © 2010 Elsevier B.V. All rights reserved.

  14. Vibrational Spectroscopy of Chromatographic Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Jeanne E. Pemberton

    2011-03-10

    Chromatographic separations play a central role in DOE-supported fundamental research related to energy, biological systems, the environment, and nuclear science. The overall portfolio of research activities in the Separations and Analysis Program within the DOE Office of Basic Energy Sciences includes support for activities designed to develop a molecular-level understanding of the chemical processes that underlie separations for both large-scale and analytical-scale purposes. The research effort funded by this grant award was a continuation of DOE-supported research to develop vibrational spectroscopic methods to characterize the interfacial details of separations processes at a molecular level.

  15. Unintended compositional changes in transgenic rice seeds ( Oryza sativa L.) studied by spectral and chromatographic analysis coupled with chemometrics methods.

    Science.gov (United States)

    Jiao, Zhe; Si, Xiao-xi; Li, Gong-ke; Zhang, Zhuo-min; Xu, Xin-ping

    2010-02-10

    Unintended compositional changes in transgenic rice seeds were studied by near-infrared reflectance, GC-MS, HPLC, and ICP-AES coupled with chemometrics strategies. Three kinds of transgenic rice with resistance to fungal diseases or insect pests were comparatively studied with the nontransgenic counterparts in terms of key nutrients such as protein, amino acids, fatty acids, vitamins, elements, and antinutrient phytic acid recommended by the Organization for Economic Co-operation and Development (OECD). The compositional profiles were discriminated by chemometrics methods, and the discriminatory compounds were protein, three amino acids, two fatty acids, two vitamins, and several elements. Significance of differences for these compounds was proved by analysis of variance, and the variation extent ranged from 20 to 74% for amino acids, from 19 to 38% for fatty acids, from 25 to 57% for vitamins, from 20 to 50% for elements, and 25% for protein, whereas phytic acid content did not change significantly. The unintended compositional alterations as well as unintended change of physical characteristic in transgenic rice compared with nontransgenic rice might be related to the genetic transformation, the effect of which needs to be elucidated by additional studies.

  16. Development and Validation of High Performance Thin-Layer Chromatographic Method for Determination of α-Mangostin in Fruit Pericarp of Mangosteen Plant (Garcinia mangostana L. using Ultraviolet – Visible Detection

    Directory of Open Access Journals (Sweden)

    Himanshu Misra

    2009-10-01

    Full Text Available A simple, fast and precise quantitative high performance thin-layer chromatographic method has been developed for quantitative estimation of α-mangostin in fruit pericarp of Garcinia mangostana L. (Hypericaceae. Best solvent for extraction of a-mangostin optimized after screening with five solvents under same conditions using hot solid-liquid extraction through soxhlet apparatus. Methanol and chloroform gave highest and second highest recovery of a-mangostin, respectively. Plates were developed in chloroform-methanol in the ratio of 27-3 (v/v. Post-chromatographic derivatization performed using anisaldehyde-sulphuric acid reagent and scanned at 382 nm in ultraviolet-visible mode. The developed method was found to be linear in the range 1.0 to 5.0 mg spot-1, limits of detection and quantitation were 150 and 450 ng spot-1. The developed method was validated in terms of system suitability, specificity and robustness.

  17. Validated thin-layer chromatographic method for the identification and monitoring of the effect of the extraction method on the yield and phytochemical constituents of Egyptian Withania somnifera leaves.

    Science.gov (United States)

    Mahrous, Rahma S R; Fathy, Hoda M; Abu El-Khair, Rasha M; Omar, Abdallah A

    2018-01-01

    A sensitive, reliable, simple and rapid thin-layer chromatographic method has been developed for routine analysis of withanolide S content for the purpose of quality control assessment of chemotype III of Withania somnifera. The new method was used first to compare the accumulation of withanolide S in different parts of the plant, which was found to be the highest in the leaves extract (0.21% w/w). Second, to investigate different extraction parameters that improve the extraction efficiency of withanolides from the leaves using conventional and ultrasound-assisted extraction methods. The extraction efficiency was expressed via total withanolide content and withanolide S content. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Determination of cyanide in blood by reaction head-space gas chromatography.

    Science.gov (United States)

    Felby, Søren

    2009-01-01

    A method describing determination of cyanide in blood by head-space gas chromatography with electron capture detector was reported. The method involves transformation of cyanide into cyanogen chloride by reacting hydrogen cyanide with chloramine-T on a stick of filter paper in the space above the blood in the head-space vial. The recovery was 84-96% and the coefficient of variation was 3.3-7.2%. The limit of quantitation was about 0.01 mg cyanide/l.

  19. Influence of headspace pressure on methane production in Biochemical Methane Potential (BMP) tests.

    Science.gov (United States)

    Valero, David; Montes, Jesús A; Rico, José Luis; Rico, Carlos

    2016-02-01

    The biochemical methane potential test is the most commonly applied method to determine methane production from organic wastes. One of the parameters measured is the volume of biogas produced which can be determined manometrically by keeping the volume constant and measuring increases in pressure. In the present study, the effect of pressure accumulation in the headspace of the reactors has been studied. Triplicate batch trials employing cocoa shell, waste coffee grounds and dairy manure as substrates have been performed under two headspace pressure conditions. The results obtained in the study showed that headspace overpressures higher than 600mbar affected methane production for waste coffee grounds. On the contrary, headspace overpressures within a range of 600-1000mbar did not affect methane production for cocoa shell and dairy manure. With the analyses performed in the present work it has not been possible to determine the reasons for the lower methane yield value obtained for the waste coffee grounds under high headspace pressures. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Liquid Chromatographic Separation of Isoniazid, Pyrazinamide and ...

    African Journals Online (AJOL)

    A gradient liquid chromatographic method which can separate isoniazid, pyrazinamide and rifampicin is described. A Hypersil Cis, 5 pm, 250 mm x 4.6 mm internal diameter column was maintained at 40°C. The method was developed by systematic evaluation of the influence of the buffer concentration, column temperature ...

  1. Liquid Chromatographic Separation of Isoniazid, Pyrazinamide and ...

    African Journals Online (AJOL)

    A gradient liquid chromatographic method which can separate isoniazid, pyrazinamide and rifampicin is described. A Hypersil C18, 5 mm, 250 mm x 4.6 mm internal diameter column was maintained at 40°C. The method was developed by systematic evaluation of the influence of the buffer concentration, column ...

  2. Liquid chromatographic analysis of phenobarbitone, ethosuximide ...

    African Journals Online (AJOL)

    A liquid chromatographic method for the simultaneous assay of four anticonvulsant drugs, phenobarbitone, ethosuximide, phenytoin and carbamazepine on a polystyrene-divinyl benzene column is described. The method was developed by the systematic study of different types of co-polymer materials, type and ...

  3. High Performance Liquid Chromatographic Determination of ...

    African Journals Online (AJOL)

    Purpose: To develop a simple, precise and rapid high-performance liquid chromatographic technique coupled with photodiode array detection (DAD) method for the simultaneous determination of rutin, quercetin, luteolin, genistein, galangin and curcumin in propolis. Methods: Ultrasound-assisted extraction was applied to ...

  4. Dynamic Cluster Analysis: An Unbiased Method for Identifying A+2 Element Containing Compounds in Liquid Chromatographic High-Resolution TOF Mass Spectrometric Data

    DEFF Research Database (Denmark)

    Andersen, Aaron John Christian; Hansen, Per Juel; Jørgensen, Kevin

    2016-01-01

    Dynamic Cluster Analysis (DCA) is an automated, unbiased technique which can identify Cl, Br, S, and other A+2 element containing metabolites in liquid chromatographic high resolution mass spectrometric data. DCA is based on three features, primarily the previously unutilised A+1 to A+2 isotope c...

  5. An high-performance liquid chromatographic method for the simultaneous analysis of acetylcarnitine taurinate, carnosine, asparagine and potassium aspartate and for the analysis of phosphoserine in alimentary supplements.

    Science.gov (United States)

    Gatti, R; Andreatta, P; Boschetti, S

    2013-07-12

    A RP-HPLC method with pre-column derivatization was developed and validated for the simultaneous quantification of carnosine (Carn), acetylcarnitine taurinate (AC-Tau), asparagine (Asn), potassium aspartate (Asp) and for the determination of phosphoserine (p-Ser) in new and commercial alimentary supplements. The effect of complex matrices was evaluated by the study of the amino acid derivatization reaction with 2,4-dinitrofluorobenzene (DNFB) both in standard and placebo solutions. The reaction was carried out for 20 min at 70 °C in alkaline medium (pH10) for p-Ser analysis, whereas for 60 min in the case of Carn, AC-Tau, Asn and Asp analysis. The adducts have been separated on a Discovery RP Amide C16 (250 mm×4.6mm, i.d.) column using a mobile phase consisting of acetonitrile (ACN) and triethylammonium (TEA) phosphate buffer (pH 3, 0.05 M) under gradient elution conditions at a flow-rate of 0.8 mL/min. Detection was set at λ=360 nm. The validation parameters such as linearity, sensitivity, accuracy, precision and specificity were found to be highly satisfactory. Linear responses were observed by placebo solutions (determination coefficient ≤0.9996). Intra-day precision (relative standard deviation, RSD) was ≤1.06% for corrected peak area and ≤0.99% for retention times (tR) without significant differences between intra- and inter-day data. Recovery studies showed good results for all examined compounds (from 97.7% to 101.5%) with RSD ranging from 0.5% to 1.3%). The high stability of derivatized compound solutions at room temperature means an undoubted advantage of the method allowing the simultaneous preparation of a large number of samples and consecutive chromatographic analyses by the use of an autosampler. The developed method can be considered suitable for the quality control of new and commercial products. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Primary Polymer Aging Processes Identified from Weapon Headspace Chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Chambers, D M; Bazan, J M; Ithaca, J G

    2002-03-25

    A current focus of our weapon headspace sampling work is the interpretation of the volatile chemical signatures that we are collecting. To help validate our interpretation we have been developing a laboratory-based material aging capability to simulate material decomposition chemistries identified. Key to establishing this capability has been the development of an automated approach to process, analyze, and quantify arrays of material combinations as a function of time and temperature. Our initial approach involves monitoring the formation and migration of volatile compounds produced when a material decomposes. This approach is advantageous in that it is nondestructive and provides a direct comparison with our weapon headspace surveillance initiative. Nevertheless, this approach requires us to identify volatile material residue and decomposition byproducts that are not typically monitored and reported in material aging studies. Similar to our weapon monitoring method, our principle laboratory-based method involves static headspace collection by solid phase microextraction (SPME) followed by gas chromatography/mass spectrometry (GC/MS). SPME is a sorbent collection technique that is ideally suited for preconcentration and delivery of trace gas-phase compounds for analysis by GC. When combined with MS, detection limits are routinely in the low- and sub-ppb ranges, even for semivolatile and polar compounds. To automate this process we incorporated a robotic sample processor configured for SPME collection. The completed system will thermally process, sample, and analyze a material sample. Quantification of the instrument response is another process that has been integrated into the system. The current system screens low-milligram quantities of material for the formation or outgas of small compounds as initial indicators of chemical decomposition. This emerging capability offers us a new approach to identify and non-intrusively monitor decomposition mechanisms that are

  7. Headspace analysis of Italian and New Zealand parmesan cheeses.

    Science.gov (United States)

    Langford, Vaughan S; Reed, Christine J; Milligan, Daniel B; McEwan, Murray J; Barringer, Sheryl A; Harper, W James

    2012-06-01

    New Zealand is a leader in the global dairy industry. Milk powder is the principal export product, but there is also a prominent cheese manufacturing industry, catering more for the domestic market. The Selected Ion Flow Tube-Mass Spectrometric (SIFT-MS) technique was used to compare 4 New Zealand cheeses marketed as "parmesan" with 4 Italian Parmigiano Reggiano and Grana Padano cheeses. The cheese headspace was analyzed in real time without any sample preconcentration. Total of 38 volatile compounds in the cheese headspace were monitored with headspace concentrations varying between single digit parts per billion (ppb) to tens of parts per million (ppm). When the results were subjected to multivariate statistical analysis, a clear discrimination was found between the New Zealand "parmesan" and Italian cheeses based solely on the measured concentrations of these volatile compounds. If the volatile compounds used in the analyses were restricted to known odor-active compounds in Parmigiano Reggiano cheese, the ability to discriminate between the cheeses was maintained. The analyses also showed that it was possible to clearly differentiate between the different processing plants in individual countries. Important discriminatory volatiles in the samples tested were butanoic acid and phenylacetaldehyde for discriminating between Italian cheeses and ethyl butyrate, acetaldehyde and methylbutanals between New Zealand cheeses. We conclude that the New Zealand "parmesans" do not provide a good representation of the aroma of Italian "parmesans." SIFT-MS has been shown to clearly differentiate both country of origin and the manufacturer of "parmesan" cheeses made in Italy and New Zealand based on differences in volatile organic compounds. Thus this method will have benefit for use in the quality control of "parmesan" and other cheese varieties. © 2012 Institute of Food Technologists®

  8. Liquid chromatographic analysis of nitration of diphenylamine stabilizer in explosives. [PBX-9404

    Energy Technology Data Exchange (ETDEWEB)

    MacDougall, C.S.

    1975-12-01

    A high speed liquid chromatographic method was developed for the quantitative analysis of nitrated diphenylamines in PBX-9404. The procedure included extraction of the nitrated diphenylamines into methylene chloride, followed by chromatographic separation and examination of the various species. The method requires a 10-g sample of high explosive in order to provide a sample of nitro DPA suitably concentrated for chromatographic analysis. (auth)

  9. Analysis of hexachlorocyclohexanes in aquatic samples by one-step microwave-assisted headspace controlled-temperature liquid-phase microextraction and gas chromatography with electron capture detection.

    Science.gov (United States)

    Tsai, Ming-Yuen; Kumar, Ponnusamy Vinoth; Li, Hong-Ping; Jen, Jen-Fon

    2010-03-19

    A microwave-assisted headspace controlled-temperature liquid-phase microextraction (HS-CT-LPME) technique was applied for the one-step sample extraction of hexachlorocyclohexanes (HCHs) from aqueous samples with complicate matrices, followed by gas chromatographic (GC) analysis with electron capture detector (ECD). Microwave heating was applied to accelerate the evaporation of HCHs into the headspace and an external-cooling system was used to control the temperature in the sampling zone for HS-LPME. Parameters affecting extraction efficiency, such as LPME solvent, sampling position and temperature, microwave power and irradiation time (the same as sampling time), sample pH, and salt addition were thoroughly investigated. From experimental results, the following conditions were selected for the extraction of HCHs from 10-mL water sample (pH 2.0) by using 1-octanol as the LPME solvent, with sampling done at 38 degrees C for 6 min under 167 W of microwave irradiation. The detections were linear in the concentration of 0.1-10 microg/L for alpha-HCH and gamma-HCH, and 1-100 microg/L for beta-HCH and delta-HCH. Detection limits were 0.05, 0.4, 0.03 and 0.1 microg/L for alpha-, beta-, gamma- and delta-HCH, respectively. Environmental water samples were analyzed with recovery between 86.4% and 102.4% for farm-field water, and between 92.2% and 98.6% for river water. The proposed method proved to serve as a simple, rapid, sensitive, inexpensive, and eco-friendly procedure for the determination of HCHs in aqueous samples. Copyright 2010 Elsevier B.V. All rights reserved.

  10. Liquid chromatographic determination of pyrethroid insecticide ...

    African Journals Online (AJOL)

    A new high performance liquid chromatography (HPLC) method for the quantitative analysis of cypermethrin in vegetable samples has been described. The determination of cypermethrin was carried out on Kromosil C18 analytical column (250 mm × 4.6 mm I.D., 5 μm particle size), under reversed phase chromatographic ...

  11. Antidiarrhoeal Activity of Chromatographic Fractions of ...

    African Journals Online (AJOL)

    Purpose: The present study was undertaken in order to evaluate the antidiarrhoeal activity of three chromatographic fractions (L, S and Y) of Stereospermum kunthianum stem bark in mice. Methods: Vacuum liquid/column chromatography (VLC/ CC) were used to obtain three fractions (L,S and Y) of Stereospermum ...

  12. Differentiating organically and conventionally grown oregano using ultraperformance liquid chromatography mass spectrometry (UPLC-MS), headspace gas chromatography with flame ionization detection (headspace-GC-FID), and flow injection mass spectrum (FIMS) fingerprints combined with multivariate data analysis.

    Science.gov (United States)

    Gao, Boyan; Qin, Fang; Ding, Tingting; Chen, Yineng; Lu, Weiying; Yu, Liangli Lucy

    2014-08-13

    Ultraperformance liquid chromatography mass spectrometry (UPLC-MS), flow injection mass spectrometry (FIMS), and headspace gas chromatography (headspace-GC) combined with multivariate data analysis techniques were examined and compared in differentiating organically grown oregano from that grown conventionally. It is the first time that headspace-GC fingerprinting technology is reported in differentiating organically and conventionally grown spice samples. The results also indicated that UPLC-MS, FIMS, and headspace-GC-FID fingerprints with OPLS-DA were able to effectively distinguish oreganos under different growing conditions, whereas with PCA, only FIMS fingerprint could differentiate the organically and conventionally grown oregano samples. UPLC fingerprinting provided detailed information about the chemical composition of oregano with a longer analysis time, whereas FIMS finished a sample analysis within 1 min. On the other hand, headspace GC-FID fingerprinting required no sample pretreatment, suggesting its potential as a high-throughput method in distinguishing organically and conventionally grown oregano samples. In addition, chemical components in oregano were identified by their molecular weight using QTOF-MS and headspace-GC-MS.

  13. Dynamic headspace time-extended helix liquid-phase microextraction.

    Science.gov (United States)

    Huang, Shih-Pin; Chen, Pai-Shan; Huang, Shang-Da

    2009-05-15

    Liquid-phase microextraction (LPME) has been proved to be a fast, inexpensive and effective sample pre-treatment technique for the analyses of pesticides and many other compounds. In this investigation, a new headspace microextraction technique, dynamic headspace time-extended helix liquid-phase microextraction (DHS-TEH-LPME), is presented. In this work, use of a solvent cooling system, permits the temperature of the extraction solvent to be lowered. Lowering the temperature of the extraction solvent not only reduces solvent loss but also extends the feasible extraction time, thereby improving extraction efficiency. Use of a larger volume of the solvent not only extends the feasible extraction time but also, after extraction, leaves a larger volume to be directly injected into the gas chromatography (GC) to increase extraction efficiency and instrument signal. The DHS-TEH-LPME technique was used to extract six organochlorine pesticides (OCPs) from 110ml water samples that had been spiked with the analytes at ng/l levels, and stirred for 60min. The proposed method attained enrichments up to 2121 fold. The effects of extraction solvent identity, sample agitation, extraction time, extraction temperature, and salt concentration on extraction performance were also investigated. The method detection limits (MDLs) varied from 0.2 to 25ng/l. The calibration curves were linear for at least 2 orders of magnitude with R(2)>==0.996. Relative recoveries in river water were more than 86%.

  14. Serum 25-hydroxyvitamin D assay. Evalution of chromatographic and non-chromatographic procedures.

    Science.gov (United States)

    Skinner, R K; Wills, M R

    1977-11-01

    A competitive protein binding assay for serum 25-hydroxyvitamin D is described in which normal human serum is used as the source of binding protein. A serum sample is extracted with diethyl ether/methanol and then chromatographed using silica gel. Validation of the method is reported. Silica gel chromatography is compared with LH20 chromatography. The method is also compared with extraction techniques using diethyl ether and ethanol without subsequent chromatography. It is concluded that chromatography with either silica gel or LH20 is essential. The non-chromatographic methods investigated, in addition to giving much higher values than chromatographic methods, did not meet validation requirements with respect to accuracy and behaviour of samples on dilution.

  15. Reversed-phase ion-pair liquid chromatographic method for determination of reaction equilibria involving ionic species: exemplification of the method using ligand substitution reactions of ethylenediaminetetraacetatochromium(III) ion with acetate and phosphate ions.

    Science.gov (United States)

    Sato, Emiko; Miya, Seiko; Saitoh, Kazunori; Saito, Shingo; Shibukawa, Masami

    2011-02-18

    A reversed-phase ion-pair liquid chromatographic method is presented for the determination of reaction equilibria involving ionic species of the same charge sign as reactant and product compounds. It has been demonstrated that ion-exchange chromatography or reversed-phase ion-pair chromatography is a useful tool for the determination of equilibrium constants of chemical reactions involving ionic species such as metal complexation reactions. Previous work with these methods has been based on the assumption that the limiting retention factors of the reactant and product species are constant independent of concentration of the chemical species (X) in the mobile phase, which reacts with the analyte compound. However, when all the reactant and product species are ions of the same charge sign as that of the species X, it is virtually impossible to apply these methods to the equilibrium constant determination because the retention factors of both the reactant and product species may depend on the concentration of X. In this study, an alternative approach was developed that estimates the limiting retention factors of ionic species from the dependence of the retention factor on the ionic strength of the mobile phase. Ligand substitution reactions of ethylenediaminetetraacetatochromium(III) ion with acetate and phosphate ions were used as model reactions to test this method. The equilibrium constants determined by this method are in good agreement with those obtained by a UV-visible spectrophotometric method. Copyright © 2010 Elsevier B.V. All rights reserved.

  16. Multielemental speciation analysis of organometallic compounds of mercury, lead and tin in natural water samples by headspace-solid phase microextraction followed by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Centineo, Giuseppe; González, Elisa Blanco; Sanz-Medel, Alfredo

    2004-04-23

    The development of a simple and rapid multielemental speciation method is described with the ultimate goal to simultaneously determine various organometallic compounds of mercury, lead and tin (inorganic mercury, methylmercury, trimethyllead, triethyllead, monobutyl-, dibutyl- and tributyltin) in natural water samples. The analytical method consists on the ethylation with NaBEt4, simultaneous headspace-solid phase microextraction (HS-SPME) of the derivatives and final gas chromatographic-mass spectrometric (GC-MS) analysis. After optimization of important process parameters, like SPME fiber coating, extraction time and extraction temperature, the analytical characteristics were evaluated. Detection limits in the low ng l(-1) level, linearity over three orders of magnitude and repeatability in the range of 3-20% were achieved for all compounds under study. The accuracy of the method in terms of average percentage recovery of the compounds in spiked river water and seawater samples was better than 90%. Finally, application of the proposed method to real natural aqueous samples enabled the simultaneous determination of all the compounds under study in seawater samples obtained from the marina area of Gijón (Asturias, Spain).

  17. High performance liquid chromatographic method for the determination of cetirizine and ambroxol in human plasma and urine--a boxcar approach.

    Science.gov (United States)

    Dharuman, J; Vasudhevan, M; Ajithlal, T

    2011-09-01

    A column switching high performance liquid chromatographic method with estimable sensitivity and accuracy was developed for the determination of cetirizine and ambroxol in human plasma using nebivolol as the internal standard. Plasma samples were prepared by liquid-liquid extraction in methylene chloride and a mixture of diethylether (80:20, v/v). The extracted samples were injected into a multifunctional clean-up column Supelcosil LCABZ (50 mm × 4.6 mm, 5 μm particle size) using mobile phase 1 comprising acetonitrile-phosphate buffer (pH 3.5; 20 mM) (20:80, v/v). The eluate of cetirizine and ambroxol were separated to an analytical Kromasil C(8) micro bore column (50 mm × 0.3 mm, 5 μm particle size) via a column switching device. A Kromasil C(18) analytical column (250 mm × 2.1 mm, 5 μm particle size) was used as a separation column. Mobile phase 2 consisting acetonitrile-triethylamine (0.5%) in phosphate buffer (pH 3.5; 20mM) (55:45, v/v) was used for the compound elution. The eluents were detected at 230 nm with photodiode array detector. An aliquot of 150 μl of plasma sample was introduced into the pretreatment column via the auto sampler using mobile phase 1 at a flow rate of 0.5 ml/min, column switching valve being positioned at A. The pretreatment column retained cetirizine, ambroxol and nebivolol (IS) in the column leaving the residual proteins of plasma eluted in void volume and drained out. The switching valve was shifted to position B at 7.5 min. Cetirizine, ambroxol and IS were eluted from the pretreatment column between 7. 5 and 11.5 min and introduced to the concentration column. Finally, cetirizine, ambroxol and IS were introduced to the separation column by switching valve using mobile phase 2 at a flow rate of 0.4 ml/min. During the analysis the pretreatment column was washed for the next analysis and resume to the position A. The total run time was 25 min for a sample. The procedure was repeated for urine analysis also. The method was

  18. Use of headspace gas chromatographic/FTIR for the monitoring of volatiles in commercial brand coffees

    Science.gov (United States)

    Compton, Senja V.; Compton, David A.

    1989-12-01

    Recently, the area of food analysis and product safety has become of major concern to consumers. Therefore, companies involved in the quality assurance of theirproducts have been encouraged to perform extensive analyses to guarantee safety and satisfaction. One of the largest consumer products in the beverage marketplace is coffee. Much emphasis has been placed upon the safety of the decaffeination processes used by various manufacturers; these involve extraction of the caffeine by a solvent system that may be aqueous or organic, and is sometimes,super-critical. Additionally, aroma (fragrance) of brewing coffee has been found to be of major concern to the individual by the marketing departments of the coffee companies. The heads ace analysis of coffees can be used to discover the species retained after the decaffeination of coffee, as well as to distinguish the volatile species released upon treatment of the coffee at boiling water temperatures.

  19. Solvent desorption dynamic headspace sampling of fermented dairy product volatiles.

    Science.gov (United States)

    Rankin, S A

    2001-01-01

    A method was developed based on solvent desorption dynamic headspace analysis for the identification and relative quantification of volatiles significant to the study of fermented dairy product aroma. Descriptions of applications of this method are presented including the measurement of diacetyl and acetoin in fermented milk, the evaluation of volatile-hydrocolloid interactions in dairy-based matrices, and the identification of volatiles in cheeses for canonical discriminative analysis. Advantages of this method include rapid analysis, minimal equipment investment, and the ability to analyze samples with traditional GC split/splitless inlet systems. Limitations of this method are that the sample must be in the liquid state and the inherent analytical limitation to those compounds that do not coelute with the solvent or solvent impurity peaks.

  20. Non-Chromatographic Purification of Endohedral Metallofullerenes.

    Science.gov (United States)

    Wang, Zhiyong; Omachi, Haruka; Shinohara, Hisanori

    2017-04-29

    The purification of endohedral metallofullerenes by high performance liquid chromatography is very time-consuming and expensive. A number of rapid and inexpensive non-chromatographic methods have thus been developed for large-scale purification of metallofullerenes. In this review, we summarize recent advances in non-chromatographic purification methods of metallofullerenes. Lewis acid-based complexation is one of the most efficient and powerful methods for separation of metallofullerenes from empty fullerenes. The first oxidation potential of metallofullerenes is a critical factor that affects the separation efficiency of the Lewis acid-based method. Supramolecular methods are effective for separation of fullerenes and metallofullerenes that are different in size and shape. Chemical/electrochemical reduction and exohedral functionalization are also utilized to separate and purify metallofullerenes on a large scale.

  1. Pharmacognostic and chromatographic standardization of ...

    African Journals Online (AJOL)

    Pharmacognostic and chromatographic evaluation of Calyptrochilum emarginatum (SW.) a potential drug plant belonging to the orchid family was carried out. High performance liquid chromatographic standardization of the methanol extract revealed sixteen compounds one of which had the same retention time 6.8 minutes ...

  2. Microminiature gas chromatograph

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Conrad M. (Antioch, CA)

    1996-01-01

    A microminiature gas chromatograph (.mu.GC) comprising a least one silicon wafer, a gas injector, a column, and a detector. The gas injector has a normally closed valve for introducing a mobile phase including a sample gas in a carrier gas. The valve is fully disposed in the silicon wafer(s). The column is a microcapillary in silicon crystal with a stationary phase and is mechanically connected to receive the mobile phase from the gas injector for the molecular separation of compounds in the sample gas. The detector is mechanically connected to the column for the analysis of the separated compounds of sample gas with electronic means, e.g., ion cell, field emitter and PIN diode.

  3. Microminiature gas chromatograph

    Energy Technology Data Exchange (ETDEWEB)

    Yu, C.M.

    1996-12-10

    A microminiature gas chromatograph ({mu}GC) comprising a least one silicon wafer, a gas injector, a column, and a detector. The gas injector has a normally closed valve for introducing a mobile phase including a sample gas in a carrier gas. The valve is fully disposed in the silicon wafer(s). The column is a microcapillary in silicon crystal with a stationary phase and is mechanically connected to receive the mobile phase from the gas injector for the molecular separation of compounds in the sample gas. The detector is mechanically connected to the column for the analysis of the separated compounds of sample gas with electronic means, e.g., ion cell, field emitter and PIN diode. 7 figs.

  4. Fast analysis of volatile components of Achillea tenuifolia Lam with microwave distillation followed by headspace single-drop microextraction coupled to gas chromatography-mass spectrometry (GC-MS).

    Science.gov (United States)

    Piryaei, Marzieh; Nazemiyeh, Hossein

    2016-01-01

    This article investigates the effect of microwaves on the amount of volatile compounds Achillea tenuifolia Lam with two methods, headspace single-drop microextraction and microwave-assisted headspace single-drop microextraction (MA-SDME), for the analysis of essential oil. Solvent selection, solvent volume, microwave power, irradiation time and sample mass were optimised by the simplex method.

  5. Floral scent of brazilian Passiflora: five species analised by dynamic headspace

    Directory of Open Access Journals (Sweden)

    DANIEL A.V. MONTERO

    2016-01-01

    Full Text Available ABSTRACT This study describes for the first time the chemical composition and olfactive description of floral scent from Brazilian Passiflora (Passiflora edulis Sim, Passiflora alata Curtis, Passiflora cincinnata Mast., Passiflora coccinea Aubl. and Passiflora quadrangularis L.. Five species were grown in greenhouse at the Agronomic Institute (IAC, São Paulo, Brazil. Volatile compounds were collected using dynamic headspace. Analyses of scent composition were performed by gas chromatograph coupled to mass spectrometer. Identification of chemical constituents was conducted through of retention index followed by comparative analysis of mass spectra with specialized databases. The olfactive descriptions of floral scent from each species was evaluated for a professional perfumer. High interspecific diversity was found between chemical compositions of floral scent within Passiflora and different bouquets were observed amount the studied species. Mayor constituents were linalool (P. alata, geraniol (P. quadrangularis, 1,4-dimethoxybenzene (P. edulis, benzaldehyde (P. cincinnata and 2-methyl-3-pentanone (P. coccinea.

  6. QuEChERS Method Followed by Solid Phase Extraction Method for Gas Chromatographic-Mass Spectrometric Determination of Polycyclic Aromatic Hydrocarbons in Fish

    Directory of Open Access Journals (Sweden)

    Mona Khorshid

    2015-01-01

    Full Text Available A gas chromatography equipped with mass spectrometer (GCMS method was developed and validated for determination of 16 polycyclic aromatic hydrocarbons (PAHs in fish using modified quick, easy, cheap, effective, rugged, and safe (QuEChERS method for extraction and solid phase extraction for sample cleanup to remove most of the coextract combined with GCMS for determination of low concentration of selected group of PAHs in homogenized fish samples. PAHs were separated on a GCMS with HP-5ms Ultra Inert GC Column (30 m, 0.25 mm, and 0.25 µm. Mean recovery ranged from 56 to 115%. The extraction efficiency was consistent over the entire range where indeno(1,2,3-cdpyrene and benzo(g,h,iperylene showed recovery (65, 69%, respectively, at 2 µg/kg. No significant dispersion of results was observed for the other remaining PAHs and recovery did not differ substantially, and at the lowest and the highest concentrations mean recovery and RSD% showed that most of PAHs were between 70% and 120% with RSD less than 10%. The measurement uncertainty is expressed as expanded uncertainty and in terms of relative standard deviation (at 95% confidence level is ±12%. This method is suitable for laboratories engaged daily in routine analysis of a large number of samples.

  7. 32-Week Holding-Time Study of SUMMA Polished Canisters and Triple Sorbent Traps Used To Sample Organic Constituents in Radioactive Waste Tank Vapor Headspace

    Energy Technology Data Exchange (ETDEWEB)

    Evans, John C.(BATTELLE (PACIFIC NW LAB)); Huckaby, James L.(BATTELLE (PACIFIC NW LAB)); Mitroshkov, Alexandre V.(BATTELLE (PACIFIC NW LAB)); Julya, Janet L.(BATTELLE (PACIFIC NW LAB)); Hayes, James C.(BATTELLE (PACIFIC NW LAB)); Edwards, Jeffrey A.(LOS ALAMOS TECH ASSOC); Sasaki, Leela M.(CH2M HILL HANF GROUP INC)

    1997-11-01

    Two sampling methods[SUMMA polished canisters and triple sorbent traps (TSTs)] were compared for long-term storage of trace organic vapor samples collected from the headspaces of high-level radioactive waste tanks at the U.S. Department of Energy's Hanford Site in Washington State. Because safety, quality assurance, radiological controls, the long-term stability of the sampling media during storage needed to be addressed. Samples were analyzed with a gas chromatograph/mass spectrometer (GC/MS) using cryogenic reconcentration or thermal desorption sample introduction techniques. SUMMA canister samples were also analyzed for total non-methane organic compounds (TNMOC) by GC/flame ionization detector (FID) using EPA Compendium Method TO-12 . To verify the long-term stability of the sampling media, multiple samples were collected in parallel from a typical passively ventilated radioactive waste tank known to contain moderately high concentrations of both polar and nonpolar organic compounds. Analyses for organic analytes and TNMOC were conducted at increasing intervals over a 32-week period to determine whether any systematic degradation of sample integrity occurred. Analytes collected in the SUMMA polished canisters generally showed good stability over the full 32 weeks with recoveries at the 80% level or better for all compounds studied. The TST data showed some loss (50-80% recovery) for a few high-volatility compounds even in the refrigerated samples; losses for unrefrigerated samples were far more pronounced with recoveries as low as 20% observed in a few cases.

  8. Application of headspace and direct immersion solid-phase microextraction in the analysis of organothiophosphates related to the Chemical Weapons Convention from water and complex matrices.

    Science.gov (United States)

    Althoff, Marc André; Bertsch, Andreas; Metzulat, Manfred; Klapötke, Thomas M; Karaghiosoff, Konstantin L

    2017-11-01

    The successful application of headspace (HS) and direct immersion (DI) solid phase microextraction (SPME) for the unambiguous identification and characterization of a series of toxic thiophosphate esters, such as Amiton (I), from aqueous phases and complex matrices (e.g. grass and foliage) has been demonstrated. A Thermo Scientific gas chromatograph (GC) - tandem mass spectrometer (MS/MS) system with a TriPlus RSH® autosampler and a SPME tool was used to investigate the effect of different parameters that influence the extraction efficiency: e.g. pH of the sample matrix and extraction temperature. The developed methods were employed for the detection of several Amiton derivatives (Schedule II of the CWC) that are structurally closely related to each other; some of which are new and have not been reported in literature previously. In addition, a novel DI SPME method from complex matrices for the analysis of organophosphates related to the CWC was developed. The studies clearly show that DI SPME for complex matrices is superior to HS extraction and can potentially be applied to other related compounds controlled under the CWC. Copyright © 2017. Published by Elsevier B.V.

  9. Measurement of H2S in Crude Oil and Crude Oil Headspace Using Multidimensional Gas Chromatography, Deans Switching and Sulfur-selective Detection.

    Science.gov (United States)

    Heshka, Nicole E; Hager, Darcy B

    2015-12-10

    A method for the analysis of dissolved hydrogen sulfide in crude oil samples is demonstrated using gas chromatography. In order to effectively eliminate interferences, a two dimensional column configuration is used, with a Deans switch employed to transfer hydrogen sulfide from the first to the second column (heart-cutting). Liquid crude samples are first separated on a dimethylpolysiloxane column, and light gases are heart-cut and further separated on a bonded porous layer open tubular (PLOT) column that is able to separate hydrogen sulfide from other light sulfur species. Hydrogen sulfide is then detected with a sulfur chemiluminescence detector, adding an additional layer of selectivity. Following separation and detection of hydrogen sulfide, the system is backflushed to remove the high-boiling hydrocarbons present in the crude samples and to preserve chromatographic integrity. Dissolved hydrogen sulfide has been quantified in liquid samples from 1.1 to 500 ppm, demonstrating wide applicability to a range of samples. The method has also been successfully applied for the analysis of gas samples from crude oil headspace and process gas bags, with measurement from 0.7 to 9,700 ppm hydrogen sulfide.

  10. Grains colonised by moulds: fungal identification and headspace analysis of produced volatile metabolites

    Directory of Open Access Journals (Sweden)

    Maria Paola Tampieri

    2010-01-01

    Full Text Available The aim of this work was to verify if the headspace analysis of fungal volatile compounds produced by some species of Fusarium can be used as a marker of mould presence on maize. Eight samples of maize (four yellow maize from North Italy and four white maize from Hungary, naturally contaminated by Fusarium and positive for the presence of fumonisins, were analyzed to detect moisture content, Aw, volatile metabolites and an enumeration of viable moulds was performed by means of a colony count technique. Headspace samples were analysed using a gas-chromatograph equipped with a capillary column TR-WAX to detect volatile metabolites of moulds. Furthermore macro and microscopic examination of the colonies was performed in order to distinguish, according to their morphology, the genera of the prevalent present moulds. Prevalent mould of eight samples was Fusarium, but other fungi, like Aspergillus, Penicillum and Mucoraceae, were observed. The metabolites produced by F.graminearum and F. moniliforme were Isobutyl-acetate, 3-Methyl-1-butanol and, only at 8 days, 3-Octanone. The incubation time can affect off flavour production in consequence of the presence of other moulds. Further studies on maize samples under different conditions are needed in order to establish the presence of moulds using the count technique and through the identification of volatile compounds.

  11. Static and dynamic headspace analysis of instant coffee blends by proton-transfer-reaction mass spectrometry.

    Science.gov (United States)

    Romano, Andrea; Gaysinsky, Sylvia; Czepa, Andreas; Del Pulgar, José Sanchez; Cappellin, Luca; Biasioli, Franco

    2015-09-01

    Instant coffee is a widespread product, generally related to a high consumer acceptability, also because of its ease of preparation. The present work addresses the characterization of the headspace of freshly brewed instant coffees resulting from different blends, during and immediately after preparation. The sample set consisted of 10 coffees, obtained by mixing three different blends in different proportions. The employment of Proton Transfer Reaction-Mass Spectrometry (PTR-MS) allowed for direct and real-time sampling from the headspace, under conditions that mimic those that are encountered above the cup during and right after brewing. Different coffee brews were separated on the basis of the respective volatile profiles, and data showed good consistency with the respective blend compositions. When the headspace evolution was monitored during preparation, similar results were obtained in terms of blend separation; moreover, different blends displayed different and reproducible 'signatures' in terms of time evolution. A straightforward method for the prediction of headspace composition is proposed, allowing to predict the volatile profiles of two-component and three-component blends on the basis of the respective parent components. Overall, the results constitute a successful example of the applicability of PTR-MS as a tool for product development in food science. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  12. Headspace Fourier transform infrared spectroscopy for the differentiation of Pandanus species.

    Science.gov (United States)

    Aganda, Kim Christopher C; Nonato, Maribel G; Sevilla, Fortunato; Santiago, Karen S

    2017-03-01

    Headspace Fourier Transform Infrared Spectroscopy (HS-FTIR) in tandem with chemometrics was applied to differentiate several species of the genus Pandanus. The headspace was generated from each Pandanus sample after incubation in a tightly sealed sample chamber. The resulting FTIR spectra of the headspace samples were found to be almost similar, but the application of principal component analysis (PCA) effectively differentiated the species. The unique spectral features for some samples were highlighted in the second-derivative FTIR spectra. A higher variance was exhibited in the PCA bi-plot of the 2nd derivative spectral data. The principal components differentiated not only the species, but also the cultivars or varieties, which formed distinct but proximate clusters. The manner of clustering obtained in this study resembled the behavior reported in a Random Amplified Polymorphic DNA analysis conducted on the Pandanus samples. The results demonstrate the potential of headspace FTIR spectroscopy as a simple, rapid, non-destructive, and relatively inexpensive method to discriminate between plant species and varieties. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Technical note: Headspace analysis of explosive compounds using a novel sampling chamber.

    Science.gov (United States)

    DeGreeff, Lauryn; Rogers, Duane A; Katilie, Christopher; Johnson, Kevin; Rose-Pehrsson, Susan

    2015-03-01

    The development of instruments and methods for explosive vapor detection is a continually evolving field of interest. A thorough understanding of the characteristic vapor signatures of explosive material is imperative for the development and testing of new and current detectors. In this research a headspace sampling chamber was designed to contain explosive materials for the controlled, reproducible sampling and characterization of vapors associated with these materials. In a detonation test, the chamber was shown to contain an explosion equivalent to three grams of trinitrotoluene (TNT) without damage to the chamber. The efficacy of the chamber in controlled headspace sampling was evaluated in laboratory tests with bulk explosive materials. Small quantities of TNT, triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD) were separately placed in the sampling chamber, and the headspace of each material was analyzed by gas chromatography/mass spectrometry (GC/MS) with online cryogenic trapping to yield characteristic vapor signatures for each explosive compound. Chamber sampling conditions, temperature and sampling time, were varied to demonstrate suitability for precise headspace analysis. Published by Elsevier Ireland Ltd.

  14. Determination of isocyanate groups in the organic intermediates by reaction-based headspace gas chromatography.

    Science.gov (United States)

    Xie, Wei-Qi; Chai, Xin-Sheng

    2016-10-14

    This work reports on a novel method for the determination of isocyanate groups in the related organic intermediates by a reaction-based headspace gas chromatography. The method is based on measuring the CO2 formed from the reaction between the isocyanate groups in the organic intermediates and water in a closed headspace sample vial at 45°C for 20min. The results showed that the method has a good precision and accuracy, in which the relative standard deviation in the repeatability measurement was 5.26%, and the relative differences between the data obtained by the HS-GC method and the reference back-titration method were within 9.42%. The present method is simple and efficient and is particularly suitable to be used for determining the isocyanate groups in the batch sample analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Contemporary Sample Preparation Methods for the Detection of Ignitable Liquids in Suspect Arson Cases.

    Science.gov (United States)

    Bertsch, W; Ren, Q

    1999-12-01

    The isolation of ignitable liquid components, usually petroleum-based distillates from fire debris, is an important step in deciding whether a fire is of natural or incendiary origin. Steady progress has been made to develop sample preparation methods capable of enriching target analytes in high yield and within a short period of time. Heated headspace enrichment methods are currently most widely used. There are several variations of this basic technique. Carbon-based adsorbents are most popular. They come in different forms and shapes, including a flat sheet of polymer, impregnated with carbon particles. The analyst cuts a small strip from this sheet and suspends it in the heated headspace above the debris sample. The volatiles adsorb onto the carbon surface, eventually reaching an equilibrium condition. The process is usually carried out in an oven. This convenient method, called the static method, has largely replaced the dynamic method, which uses a granular charcoal adsorbent. In the latter, the heated headspace is drawn over a short trap packed with charcoal, using a source of vacuum such as a pump or pushed along using pressurized nitrogen. The headspace volatiles in both the static and dynamic method are recovered by elution with a solvent, usually carbon disulfide. Recently, a promising variation of the static headspace method has been introduced. It is based on the use of a tiny amount of a polysiloxane polymer which has been coated onto the tip of a thin silica fiber. The fiber can be retracted into a syringe-type needle and the adsorbed headspace vapor can be conveniently introduced into the heated injector port of a gas chromatograph. No solvent is required. This technique, abbreviated SPME (for solid-phase microextraction) has many attractive advantages but it is not without some problems. Low boiling range accelerants, including water-soluble polar substances such as ethanol, are poorly retained on methylsiloxane type polymers. The recent

  16. GNS Castor V/21 Headspace Gas Sampling 2014

    Energy Technology Data Exchange (ETDEWEB)

    Winston, Philip Lon [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-01-01

    Prior to performing an internal visual inspection, samples of the headspace gas of the GNS Castor V/21 cask were taken on June 12, 2014. These samples were taken in support of the CREIPI/Japanese nuclear industry effort to validate fuel integrity without visual inspection by measuring the 85Kr content of the cask headspace

  17. Fingerprinting of the volatile fraction from selected thyme species by means of headspace gas chromatography with mass spectrometric detection.

    Science.gov (United States)

    Staszek, Dorota; Orłowska, Marta; Rzepa, Józef; Wróbel, Michał S; Kowalska, Teresa; Szymczak, Grażyna; Waksmundzka-Hajnos, Monika

    2014-01-01

    The Thymus genus has a firm position in Mediterranean folk medicine and culinary tradition, and yet certain confusion is observed in its botanical taxonomy. Therefore, chemical analysis of secondary metabolites and selection of reliable chemotaxonomic markers can prove helpful. In this study, the volatile fraction derived from 20 different thyme specimens was analyzed by means of headspace GC with MS detection. From the obtained chromatographic fingerprints, the diversity of the volatile fraction originating from the different thyme species clearly emerged. Identification of volatile components was based on a software library of mass spectra. There was only one common component derived from all 20 investigated thyme species, i.e., ß-linalool. For three different Thymus species, a comparison was made of the performance of the headspace extraction and hydrodistillation. Characteristic differences in composition of the volatile fraction obtained with use of these two techniques were discussed. Finally, the obtained chromatographic fingerprints of the volatile fraction were analyzed by means of a chemometric approach (principal component analysis), in order to trace similarities in their chemical composition.

  18. Dynamic Cluster Analysis: An Unbiased Method for Identifying A+2 Element Containing Compounds in Liquid Chromatographic High-Resolution TOF Mass Spectrometric Data

    DEFF Research Database (Denmark)

    Andersen, Aaron John Christian; Hansen, Per Juel; Jørgensen, Kevin

    2016-01-01

    over 2800 u or metabolites which contained other A+2 elements, such as Cu, Ni, Mg, and Zn. It was determined that with an inter-isotopic mass accuracy of 1 ppm, in a fully automated process, using all three parameters, it is possible to specifically filter a chromatogram for S containing metabolites......Dynamic Cluster Analysis (DCA) is an automated, unbiased technique which can identify Cl, Br, S, and other A+2 element containing metabolites in liquid chromatographic high resolution mass spectrometric data. DCA is based on three features, primarily the previously unutilised A+1 to A+2 isotope...... cluster spacing which is a strong classifier in itself, but improved with the addition of the monoisotopic mass, and the well-known A:A+2 intensity ratio. Utilizing only the A+1 to A+2 isotope cluster spacing and the monoisotopic mass it was possible to filter a chromatogram for metabolites which contain...

  19. Chromatographic fingerprint analysis of Pycnogenol dietary supplements.

    Science.gov (United States)

    Chen, Pei; Song, Fenhong; Lin, Long-Ze

    2009-01-01

    The bark of maritime pine (Pinus pinaster Aiton) has been widely used as a remedy for various degenerative diseases. A standard high-performance liquid chromatographic (HPLC) procedure for Pycnogenol analysis is a method specified in the United States Pharmacopeia (USP) monograph, which requires measurement of peak areas and identification of four components of the extract: caffeic acid, catechin, ferulic acid, and taxifolin. In this study, a fingerprint analysis using an HPLC method based on the USP monograph has been developed to provide additional qualitative information for the analysis of Pycnogenol-containing dietary supplements (PDS). Twelve commercially available PDS samples were purchased and analyzed along with a standard Pycnogenol extract. Their chromatographic fingerprints were analyzed using principal component analysis. The results showed that two of the samples were not consistent with the standard reference Pycnogenol extract. One contained other active ingredients in addition to Pycnogenol, and the other may have resulted from a quality control issue in manufacturing.

  20. Inhibiting sorbent stripping by designing a sorbent-packed porous probe for headspace solid-phase microextraction.

    Science.gov (United States)

    Qin, Shuai; Tao, Gu; Yunjie, Huang; Shuangshuang, Xu; Luyan, Li; Hongyan, Xiao

    2015-10-01

    To prevent the stripping of coating sorbents in headspace solid-phase microextraction, a porous extraction probe with packed sorbent was introduced by using a porous stainless steel needle tube and homemade sol-gel sorbents. The traditional stainless-steel needle tube was punched by a laser to obtain two rows of holes, which supply a passageway for analyte vapor during extraction and desorption. The sorbent was prepared by a traditional sol-gel method with both poly(ethylene glycol) and hydroxy-terminated silicone oil as coating ingredients. Eight polycyclic aromatic hydrocarbons and six benzene series compounds were used as illustrative semi-volatile and volatile organic compounds in sequence to verify the extraction performance of this porous headspace solid-phase microextraction probe. It was found that the analysis method combining a headspace solid-phase microextraction probe and gas chromatography with mass spectrometry yielded determination coefficients of no less than 0.985 and relative standard deviations of 4.3-12.4%. The porous headspace solid-phase microextraction probe showed no decrease of extraction ability after 200 uses. These results demonstrate that the packed extraction probe with porous structure can be used for headspace solid-phase microextraction. This novel design may overcome both the stripping and breakage problems of the conventional coating fiber. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. The application of headspace gas chromatography coupled to tandem quadrupole mass spectrometry for the analysis of furan in baby food samples.

    Science.gov (United States)

    Pugajeva, Iveta; Rozentale, Irina; Viksna, Arturs; Bartkiene, Elena; Bartkevics, Vadims

    2016-12-01

    Selective methodology employing a tandem quadrupole mass spectrometer coupled to a gas chromatograph with headspace autosampler (HS-GC-MS/MS) was elaborated in this study. Application of the elaborated procedure resulted in a limit of detection of 0.021μgkg(-1) and a limit of quantification of 0.071μgkg(-1). The mean recoveries during in-house validation ranged from 89% to 109%, and coefficients of variation for repeatability ranged from 4% to 11%. The proposed analytical method was applied for monitoring the furan content of 30 commercial baby food samples available on the Latvian retail market. The level of furan found in these samples varied from 0.45 to 81.9μgkg(-1), indicating that infants whose sole diet comprises baby food sold in jars and cans are exposed constantly to furan. Samples containing vegetables and meat had higher levels of furan than those containing only fruits. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Reconstitution of L-Asparaginase in Siliconized Syringes with Shaking and Headspace Air Induces Protein Aggregation.

    Science.gov (United States)

    Uchino, Tomonobu; Miyazaki, Yasunori; Ohkawa, Tomoyo; Yamazaki, Takuto; Yanagihara, Yoshitsugu; Yoshimori, Takayuki; Komatsu, Mamoru; Suzuki, Hiroshi; Kagawa, Yoshiyuki

    2015-01-01

    The aim of this study was to characterize protein aggregation during reconstitution of a highly concentrated solution of lyophilized L-asparaginase (L-ASP). The effect of the preparation method on L-ASP aggregation using siliconized or non-siliconized syringes and the effect of storage after preparation were evaluated by far-UV circular dichroism spectroscopy, Raman microscopy, flow cytometry, and flow particle image analysis. To investigate the effect of syringe type in combination with shaking and headspace air on L-ASP aggregation, four kinds of L-ASP in 5% glucose solutions were prepared (in the presence or absence of silicon oil and headspace air). Slight differences in L-ASP secondary structure were observed between the siliconized and non-siliconized syringe systems before shaking. Large numbers of sub-visible (0.1-100 µm) and submicron (0.1-1 µm) particles were formed by preparation with siliconized syringes and the combination of shaking and headspace air. The number of aggregated particles was not decreased with increased storage time. The Raman microscopy, flow cytometry and flow particle image results suggested that L-ASP interacted with silicone oil, which induced aggregation. Nevertheless, sub-visible and submicron particles were also formed with non-siliconized syringes. However, using non-siliconized syringes, the number of aggregated particles decreased with storage. No changes in particle character were observed before or after shaking with headspace air in non-siliconized syringes, indicating that soluble aggregates formed and dissolved with storage. Silicone oil in syringes, in combination with shaking and headspace air, strongly affected the aggregation of lyophilized L-ASP formulations during preparation.

  3. Novel proton-type ionic liquid doped polyaniline for the headspace solid-phase microextraction of amines

    Energy Technology Data Exchange (ETDEWEB)

    Ai, Youhong [Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Key Laboratory for the Synthesis and Application of Organic Functional Molecules (Ministry of Education), College of Chemistry & Chemical Engineering, Hubei University, Wuhan 430062 (China); Zhao, Faqiong [Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Zeng, Baizhao, E-mail: bzzeng@whu.edu.cn [Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China)

    2015-06-23

    Graphical abstract: The novel proton-type ionic liquid (1-sulfobutyl-3-methylimidazolium hydrosulfate) doped polyaniline coating showed granular porous nanostructure and it had high self-EF values and extraction efficiency for amines. - Highlights: • A proton-type ionic liquid-doped polyaniline was fabricated by electrodeposition. • It showed porous granular nanostructure and had large specific surface. • It had high extraction capacity to aromatic amines. • A reasonable self-enrichment factor of SPME fiber has been proposed. - Abstract: A novel proton-type ionic liquid doped polyaniline (HIL-doped PANI) coating was presented, which was prepared on a stainless steel wire by electrodeposition in an aqueous solution containing aniline and 1-sulfobutyl-3-methylimidazolium hydrosulfate. The HIL-doped PANI coating showed granular nanostructure and had large specific surface. When it was applied to the headspace solid-phase microextraction of several amines (i.e., aniline, N-methylaniline, 3-methylaniline, 2-chloroaniline and 3-chloroaniline), it showed high extraction efficiency. The enrichment factors were 191.8–343.9 for different amines, much higher than those of common PANI and commercial polydimethylsiloxane/divinylbenzene coatings. Coupled with gas chromatographic analysis, the linear ranges were 0.097–100 μg/L with correlation coefficients above 0.9942, and the detection limits were 0.012–0.048 μg/L (S/N = 3) for different amines. The relative standard deviations (RSD) were smaller than 8.1% for five successive measurements with single fiber and the fiber-to-fiber RSDs were 8.6–13.8% (n = 5) for these amines. The proposed method was successfully applied to the extraction and determination of amines in organic waste water samples, and the recoveries were 78.3–112.8% for different analytes.

  4. Headspace analysis of foams and fixatives

    Energy Technology Data Exchange (ETDEWEB)

    Harper, Kyle [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Truong, Thanh-Tam [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Magwood, Leroy [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Peters, Brent [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Nicholson, James [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Washington, II, Aaron L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-07-27

    In the process of decontaminating and decommissioning (D&D) older nuclear facilities, special precautions must be taken with removable or airborne contamination. One possible strategy utilizes foams and fixatives to affix these loose contaminants. Many foams and fixatives are already commercially available, either generically or sold specifically for D&D. However, due to a lack of revelant testing in a radioactive environment, additional verification is needed to confirm that these products not only affix contamination to their surfaces, but also will function in a D&D environment. Several significant safety factors, including flammability and worker safety, can be analyzed through the process of headspace analysis, a technique that analyzes the off gas formed before or during the curing process of the foam/fixative, usually using gas chromatography-mass spectrometry (GC-MS). This process focuses on the volatile components of a chemical, which move freely between the solid/liquid form within the sample and the gaseous form in the area above the sample (the headspace). Between possibly hot conditions in a D&D situation and heat created in a foaming reaction, the volatility of many chemicals can change, and thus different gasses can be released at different times throughout the reaction. This project focused on analysis of volatile chemicals involved in the process of using foams and fixatives to identify any potential hazardous or flammable compounds.

  5. The Application of Noninvasive Headspace Analysis to Media Fill Inspection.

    Science.gov (United States)

    Duncan, Derek; Cundell, Tony; Levac, Lauren; Veale, James; Kuiper, Suzanne; Rao, Ravi

    2016-01-01

    The results of a proof-of-principle study demonstrating a new analytical technique for detecting microbial growth directly in pharmaceutical containers are described. This analytical technique, laser-based headspace analysis, uses tunable diode laser absorption spectroscopy to nondestructively determine gas concentrations in the headspace of a media-filled pharmaceutical container. For detecting microbial growth, the levels of headspace oxygen and carbon dioxide are measured. Once aerobic microorganisms begin to divide after the lag phase and enter the exponential growth phase, there will be significant consumption of oxygen and concomitant production of carbon dioxide in the sealed container. Laser-based headspace analysis can accurately measure these changes in the headspace gas composition. The carbon dioxide and oxygen measurement data for the representative microorganisms Staphylococcus aureus, Bacillus subtilis, Candida albicans, and Aspergillus brasiliensis were modeled using the Baranyi-Roberts equation. The mathematical modeling allowed quantitative comparisons to be made between the data from the different microorganisms as well as to the known growth curves based on microbial count. Because laser-based headspace analysis is noninvasive and can be automated to analyze the headspace of pharmaceutical containers at inspection speeds of several hundred containers per minute on-line, some potential new applications are enabled. These include replacing the current manual human visual inspection with an automated analytical inspection machine to determine microbial contamination of media fill and pharmaceutical drug product vials. A novel analytical technique has been demonstrated for detecting microbial growth in media-filled pharmaceutical containers. This analytical technique, laser-based headspace analysis, uses tunable diode laser absorption spectroscopy to determine gas concentrations in the headspace of a pharmaceutical container. For detecting microbial

  6. Quantitative analysis of perfumes in talcum powder by using headspace sorptive extraction.

    Science.gov (United States)

    Ng, Khim Hui; Heng, Audrey; Osborne, Murray

    2012-03-01

    Quantitative analysis of perfume dosage in talcum powder has been a challenge due to interference of the matrix and has so far not been widely reported. In this study, headspace sorptive extraction (HSSE) was validated as a solventless sample preparation method for the extraction and enrichment of perfume raw materials from talcum powder. Sample enrichment is performed on a thick film of poly(dimethylsiloxane) (PDMS) coated onto a magnetic stir bar incorporated in a glass jacket. Sampling is done by placing the PDMS stir bar in the headspace vial by using a holder. The stir bar is then thermally desorbed online with capillary gas chromatography-mass spectrometry. The HSSE method is based on the same principles as headspace solid-phase microextraction (HS-SPME). Nevertheless, a relatively larger amount of extracting phase is coated on the stir bar as compared to SPME. Sample amount and extraction time were optimized in this study. The method has shown good repeatability (with relative standard deviation no higher than 12.5%) and excellent linearity with correlation coefficients above 0.99 for all analytes. The method was also successfully applied in the quantitative analysis of talcum powder spiked with perfume at different dosages. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Fast liquid chromatographic-tandem mass spectrometric method using mixed-mode phase chromatography and solid phase extraction for the determination of 12 mono-hydroxylated brominated diphenyl ethers in human serum.

    Science.gov (United States)

    Petropoulou, Syrago-Styliani E; Duong, Wendy; Petreas, Myrto; Park, June-Soo

    2014-08-22

    Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) are formed from the oxidative metabolism of polybrominated diphenyl ethers (PBDEs) in humans, rats and mice, but their quantitation in human blood and other matrices with liquid chromatography-mass spectrometric techniques has been a challenge. In this study, a novel analytical method was developed and validated using only 250 μL of human serum for the quantitation of twelve OH-PBDEs, fully chromatographically separated in a 15 min analytical run. This method includes two novel approaches: an enzymatic hydrolysis procedure and a chromatographic separation using a mixed mode chromatography column. The enzymatic hydrolysis (EH) was found critical for 4'-OH-BDE17, which was not detectable without it. For the sample clean up, a solid phase extraction protocol was developed and validated for the extraction of the 12 congeners from human serum. In addition, for the first time baseline resolution of two components was achieved that correspond to a single peak previously identified as 6'-OH-BDE99. The method was validated for linearity, accuracy, precision, matrix effects, limit of quantification, limit of detection, sample stability and overall efficiency. Recoveries (absolute and relative) ranged from 66 to 130% with relative standard deviations human serum samples from the general US population. The mean values of the congeners detected in all samples are 4'-OH-BDE17 (34.2 pg mL(-1)), 4-OH-BDE42 (33.9 pg mL(-1)), 5-OH-BDE47 (17.5 pg mL(-1)) and 4'-OH-BDE49 (12.4 pg mL(-1)). Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Influence of headspace pressure on methane production in Biochemical Methane Potential (BMP) tests

    OpenAIRE

    Valero Morales, David; Montes Casaus, Jesús A.; Rico Gutiérrez, José Luis; Rico de la Hera, Carlos

    2016-01-01

    ABSTRACT:The biochemical methane potential test is the most commonly applied method to determine methane production from organic wastes. One of the parameters measured is the volume of biogas produced which can be determined manometrically by keeping the volume constant and measuring increases in pressure. In the present study, the effect of pressure accumulation in the headspace of the reactors has been studied. Triplicate batch trials employing cocoa shell, waste coffee grounds and dairy ma...

  9. Uncertainty of Blood Alcohol Concentration (BAC Results as Related to Instrumental Conditions: Optimization and Robustness of BAC Analysis Headspace Parameters

    Directory of Open Access Journals (Sweden)

    Haleigh A. Boswell

    2015-12-01

    Full Text Available Analysis of blood alcohol concentration is a routine analysis performed in many forensic laboratories. This analysis commonly utilizes static headspace sampling, followed by gas chromatography combined with flame ionization detection (GC-FID. Studies have shown several “optimal” methods for instrumental operating conditions, which are intended to yield accurate and precise data. Given that different instruments, sampling methods, application specific columns and parameters are often utilized, it is much less common to find information on the robustness of these reported conditions. A major problem can arise when these “optimal” conditions may not also be robust, thus producing data with higher than desired uncertainty or potentially inaccurate results. The goal of this research was to incorporate the principles of quality by design (QBD in the adjustment and determination of BAC (blood alcohol concentration instrumental headspace parameters, thereby ensuring that minor instrumental variations, which occur as a matter of normal work, do not appreciably affect the final results of this analysis. This study discusses both the QBD principles as well as the results of the experiments, which allow for determination of more favorable instrumental headspace conditions. Additionally, method detection limits will also be reported in order to determine a reporting threshold and the degree of uncertainty at the common threshold value of 0.08 g/dL. Furthermore, the comparison of two internal standards, n-propanol and t-butanol, will be investigated. The study showed that an altered parameter of 85 °C headspace oven temperature and 15 psi headspace vial pressurization produces the lowest percent relative standard deviation of 1.3% when t-butanol is implemented as an internal standard, at least for one very common platform. The study also showed that an altered parameter of 100 °C headspace oven temperature and 15-psi headspace vial pressurization

  10. Headspace liquid-phase microextraction of methamphetamine and amphetamine in urine by an aqueous drop

    Energy Technology Data Exchange (ETDEWEB)

    He Yi [Department of Sciences, John Jay College of Criminal Justice, City University of New York, 445 W 59th Street, New York, NY 10019 (United States)]. E-mail: yhe@jjay.cuny.edu; Vargas, Angelica [Department of Sciences, John Jay College of Criminal Justice, City University of New York, 445 W 59th Street, New York, NY 10019 (United States); Kang, Youn-Jung [Department of Sciences, John Jay College of Criminal Justice, City University of New York, 445 W 59th Street, New York, NY 10019 (United States)

    2007-04-25

    This study developed a headspace liquid-phase microextraction (LPME) method by using a single aqueous drop in combination with high performance liquid chromatography (HPLC)-UV detection for the determination of methamphetamine (MAP) and amphetamine (AP) in urine samples. The analytes, volatile and basic, were released from sample matrix into the headspace first, and then protonated and dissolved in an aqueous H{sub 3}PO{sub 4} drop hanging in the headspace by a HPLC syringe. After extraction, this drop was directly injected into HPLC. Parameters affecting extraction efficiency were investigated and optimized. This method showed good linearity in the investigated concentration range of 1.0-1500 {mu}g L{sup -1}, repeatability of the extraction (R.S.D. < 5%, n = 6), and low detection limits (0.3 {mu}g L{sup -1} for both analytes). Enrichment factors of about 400-fold and 220-fold were achieved for MAP and AP, respectively, at optimum conditions. The feasibility of the method was demonstrated by analyzing human urine samples.

  11. Determination of oxadiazon residues by headspace solid-phase microextraction and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Navalón, Alberto; Prieto, Avismelsi; Araujo, Lilia; Vílchez, José Luis

    2002-02-08

    A method for the determination of trace amounts of the herbicide oxadiazon was developed using headspace solid-phase microextraction (HS-SPME), gas chromatography-mass spectrometry (GC-MS) and selected ion monitoring. It was applied to determine oxadiazon in ground water, agricultural soil, must, wine and human urine samples. To determine oxadiazon in liquid samples, a response surface methodology generated with a Doehlert design was applied to optimize the HS-SPME conditions using a 100 microm polydimethylsiloxane fibre. For the analysis of soil samples, they were mixed with water and the SPME fibre suspended in the headspace above the slurry. Ground water, human urine and must show linear concentration range of application of 0.5-50 ng ml(-1)' with detection limits matrix samples. The developed analytical procedure is solvent free, cost effective and fast.

  12. Analytical method for the identification and assay of 12 phthalates in cosmetic products: application of the ISO 12787 international standard "Cosmetics-Analytical methods-Validation criteria for analytical results using chromatographic techniques".

    Science.gov (United States)

    Gimeno, Pascal; Maggio, Annie-Françoise; Bousquet, Claudine; Quoirez, Audrey; Civade, Corinne; Bonnet, Pierre-Antoine

    2012-08-31

    Esters of phthalic acid, more commonly named phthalates, may be present in cosmetic products as ingredients or contaminants. Their presence as contaminant can be due to the manufacturing process, to raw materials used or to the migration of phthalates from packaging when plastic (polyvinyl chloride--PVC) is used. 8 phthalates (DBP, DEHP, BBP, DMEP, DnPP, DiPP, DPP, and DiBP), classified H360 or H361, are forbidden in cosmetics according to the European regulation on cosmetics 1223/2009. A GC/MS method was developed for the assay of 12 phthalates in cosmetics, including the 8 phthalates regulated. Analyses are carried out on a GC/MS system with electron impact ionization mode (EI). The separation of phthalates is obtained on a cross-linked 5%-phenyl/95%-dimethylpolysiloxane capillary column 30 m × 0.25 mm (i.d.) × 0.25 mm film thickness using a temperature gradient. Phthalate quantification is performed by external calibration using an internal standard. Validation elements obtained on standard solutions, highlight a satisfactory system conformity (resolution>1.5), a common quantification limit at 0.25 ng injected, an acceptable linearity between 0.5 μg mL⁻¹ and 5.0 μg mL⁻¹ as well as a precision and an accuracy in agreement with in-house specifications. Cosmetic samples ready for analytical injection are analyzed after a dilution in ethanol whereas more complex cosmetic matrices, like milks and creams, are assayed after a liquid/liquid extraction using ter-butyl methyl ether (TBME). Depending on the type of cosmetics analyzed, the common limits of quantification for the 12 phthalates were set at 0.5 or 2.5 μg g⁻¹. All samples were assayed using the analytical approach described in the ISO 12787 international standard "Cosmetics-Analytical methods-Validation criteria for analytical results using chromatographic techniques". This analytical protocol is particularly adapted when it is not possible to make reconstituted sample matrices. Copyright © 2012

  13. Potential Waste Tank Headspace Concentrations of DDE and 1-Naphthylamine

    Energy Technology Data Exchange (ETDEWEB)

    Mahoney, Lenna A.

    2006-02-15

    Recent studies conducted for the Hanford Waste Treatment Plant (WTP) found that the centrifuged solids from tanks 241-AW-101, 241-AN-107, and 241-C-104 contained two carcinogenic chemicals, 1-naphthylamine and 2,2-bis(4-chlorophenyl)-1,1-dichloroethene (DDE), that had never been detected in tank headspaces. This report estimates the potential headspace concentrations associated with these two compounds. The calculation was based on a comparison of headspace concentrations and waste concentrations for sixteen other organic compounds in the passively-ventilated tank 241-C-104. An approximate relation was found between the compounds? solubilities in water and their headspace concentrations. The relation was used to estimate the 241-C-104 headspace concentration that would result from the maximum measured waste concentrations of DDE and 1-naphthylamine. On the basis of the assumptions made in this report about organic compound transport and equilibration, the DDE concentration was estimated at well below one part per trillion, below standard analytical detection limits. However, 1-naphthylamine could potentially be present in the headspace of a passively ventilated tank at the 30 ppb level.

  14. Simultaneous Determination of Benzene and Toluene in Pesticide Emulsifiable Concentrate by Headspace GC-MS

    Science.gov (United States)

    Jiang, Hua; Yang, Jing; Fan, Li; Li, Fengmin; Huang, Qiliang

    2013-01-01

    The toxic inert ingredients in pesticide formulations are strictly regulated in many countries. In this paper, a simple and efficient headspace-gas chromatography-mass spectrometry (HSGC-MS) method using fluorobenzene as an internal standard (IS) for rapid simultaneous determination of benzene and toluene in pesticide emulsifiable concentrate (EC) was established. The headspace and GC-MS conditions were investigated and developed. A nonpolar fused silica Rtx-5 capillary column (30 m × 0.20 mm i.d. and 0.25 μm film thickness) with temperature programming was used. Under optimized headspace conditions, equilibration temperature of 120°C, equilibration time of 5 min, and sample size of 50 μL, the regression of the peak area ratios of benzene and toluene to IS on the concentrations of analytes fitted a linear relationship well at the concentration levels ranging from 3.2 g/L to 16.0 g/L. Standard additions of benzene and toluene to blank different matrix solutions 1ead to recoveries of 100.1%–109.5% with a relative standard deviation (RSD) of 0.3%–8.1%. The method presented here stands out as simple and easily applicable, which provides a way for the determination of toxic volatile adjuvant in liquid pesticide formulations. PMID:23607048

  15. Dynamic headspace-gas-chromatography-olfactometry analysis of different anatomical parts of lovage (Levisticum officinale Koch.) at eight growing stages

    NARCIS (Netherlands)

    Bylaite, E.; Roozen, J.P.; Legger, A.; Venskutonis, R.P.; Posthumus, M.A.

    2000-01-01

    Volatiles of five different parts of lovage (leaves, stems, flowers, seeds, and roots) were isolated by dynamic headspace (DHS) method and analyzed by GC-FID and GC-olfactometry (GC-O) techniques. In total, 98 compounds were identified in the samples, of which 41 are reported as lovage volatiles for

  16. Rapid determination of the volatile components in tobacco by ultrasound-microwave synergistic extraction coupled to headspace solid-phase microextraction with gas chromatography-mass spectrometry.

    Science.gov (United States)

    Yang, Yanqin; Chu, Guohai; Zhou, Guojun; Jiang, Jian; Yuan, Kailong; Pan, Yuanjiang; Song, Zhiyu; Li, Zuguang; Xia, Qian; Lu, Xinbo; Xiao, Weiqiang

    2016-03-01

    An ultrasound-microwave synergistic extraction coupled to headspace solid-phase microextraction was first employed to determine the volatile components in tobacco samples. The method combined the advantages of ultrasound, microwave, and headspace solid-phase microextraction. The extraction, separation, and enrichment were performed in a single step, which could greatly simplify the operation and reduce the whole pretreatment time. In the developed method, several experimental parameters, such as fiber type, ultrasound power, and irradiation time, were optimized to improve sampling efficiency. Under the optimal conditions, there were 37, 36, 34, and 36 components identified in tobacco from Guizhou, Hunan, Yunnan, and Zimbabwe, respectively, including esters, heterocycles, alkanes, ketones, terpenoids, acids, phenols, and alcohols. The compound types were roughly the same while the contents were varied from different origins due to the disparity of their growing conditions, such as soil, water, and climate. In addition, the ultrasound-microwave synergistic extraction coupled to headspace solid-phase microextraction method was compared with the microwave-assisted extraction coupled to headspace solid-phase microextraction and headspace solid-phase microextraction methods. More types of volatile components were obtained by using the ultrasound-microwave synergistic extraction coupled to headspace solid-phase microextraction method, moreover, the contents were high. The results indicated that the ultrasound-microwave synergistic extraction coupled to headspace solid-phase microextraction technique was a simple, time-saving and highly efficient approach, which was especially suitable for analysis of the volatile components in tobacco. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Poly(o-anisidine)/graphene oxide nanosheets composite as a coating for the headspace solid-phase microextraction of benzene, toluene, ethylbenzene and xylenes.

    Science.gov (United States)

    Behzadi, Mansoureh; Mirzaei, Mohammad

    2016-04-22

    A poly(o-anisidine)/graphene oxide nanosheets (PoA/GONSs) coating is fabricated by a simple and efficient electrochemical deposition method on steel wire. The incorporation of PoA and GONSs allows preparing a nanocomposite that can successfully integrate the advantages of both. Then, the prepared fiber is applied to the headspace solid-phase microextraction (HS-SPME) and gas chromatographic analysis of benzene, toluene, ethylbenzene and xylenes. In order to obtain an adherent, stable and efficient fiber to extract target analytes, experimental parameters related to the coating process such as deposition potential, deposition time, concentration of the monomer and concentration of GONSs were studied. The prepared composite fiber were characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction and scanning electron microscopy. The effect of various parameters on the efficiency of HS-SPME process consisting of desorption temperature and time, extraction temperature and time and ionic strength were also optimized. Under the optimal conditions, the method was linear for orders of magnitude with correlation coefficients varying from 0.9888 to 0.9993. Intra- and inter-day precisions of the method were determined from mixed aqueous solutions containing 5.0 ng mL(-1) of each BTEX. The intra-day precisions varied from 3.1% for toluene to 5.7% for ethylbenzene, while the inter-day precisions varied from 4.9% for o-xylene to 7.3% for m,p-xylene. Limits of detection were in the range 0.01-0.06 ng mL(-1). The proposed method was applied to monitor BTEX compounds in some water samples and the accuracies found through spiking river water samples showed high recoveries between 92.0 and 101.2%. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Accurate identification and quantification of 11-nor-delta(9)-tetrahydrocannabinol-9-carboxylic acid in urine drug testing: evaluation of a direct high efficiency liquid chromatographic-mass spectrometric method.

    Science.gov (United States)

    Stephanson, Nikolai; Josefsson, Martin; Kronstrand, Robert; Beck, Olof

    2008-08-01

    A direct liquid chromatographic-tandem mass spectrometric (LC-MS/MS) method for measurement of urinary Delta(9)-tetrahydrocannabinol carboxylic acid (THCA) was developed. The method involved dilution of the urine sample with water containing (2)H(9)-deuterated analogue as internal standard, hydrolysis with ammonia, reversed phase chromatography using a Waters ultra-performance liquid chromatography (UPLC) equipment with gradient elution, negative electrospray ionization, and monitoring of two product ions in selected reaction monitoring mode. The measuring range was 2-1000 ng/mL for THCA, and the intra- and inter-assay imprecision, expressed as the coefficient of variation, was below 5%. Influence from urine matrix on ionization efficiency was noted in infusion experiments, but was compensated for by the internal standard. Comparison with established gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry methods in authentic patient samples demonstrated accuracy in both qualitative and quantitative results. A small difference in mean ratios (~15%) may be explained by the use of different hydrolysis procedures between methods. In conclusion, the high efficiency LC-MS/MS method was capable of accurately identify and quantify THCA in urine with a capacity of 14 samples per hour.

  19. Gram-negative and -positive bacteria differentiation in blood culture samples by headspace volatile compound analysis.

    Science.gov (United States)

    Dolch, Michael E; Janitza, Silke; Boulesteix, Anne-Laure; Graßmann-Lichtenauer, Carola; Praun, Siegfried; Denzer, Wolfgang; Schelling, Gustav; Schubert, Sören

    2016-12-01

    Identification of microorganisms in positive blood cultures still relies on standard techniques such as Gram staining followed by culturing with definite microorganism identification. Alternatively, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry or the analysis of headspace volatile compound (VC) composition produced by cultures can help to differentiate between microorganisms under experimental conditions. This study assessed the efficacy of volatile compound based microorganism differentiation into Gram-negatives and -positives in unselected positive blood culture samples from patients. Headspace gas samples of positive blood culture samples were transferred to sterilized, sealed, and evacuated 20 ml glass vials and stored at -30 °C until batch analysis. Headspace gas VC content analysis was carried out via an auto sampler connected to an ion-molecule reaction mass spectrometer (IMR-MS). Measurements covered a mass range from 16 to 135 u including CO2, H2, N2, and O2. Prediction rules for microorganism identification based on VC composition were derived using a training data set and evaluated using a validation data set within a random split validation procedure. One-hundred-fifty-two aerobic samples growing 27 Gram-negatives, 106 Gram-positives, and 19 fungi and 130 anaerobic samples growing 37 Gram-negatives, 91 Gram-positives, and two fungi were analysed. In anaerobic samples, ten discriminators were identified by the random forest method allowing for bacteria differentiation into Gram-negative and -positive (error rate: 16.7 % in validation data set). For aerobic samples the error rate was not better than random. In anaerobic blood culture samples of patients IMR-MS based headspace VC composition analysis facilitates bacteria differentiation into Gram-negative and -positive.

  20. Validated column high-performance liquid chromatographic method for determination of aspirin and clopidogrel in combined tablets in the presence of degradation products formed under ICH-recommended stress conditions.

    Science.gov (United States)

    Kachhadia, Pankaj K; Doshi, Ashish S; Joshi, Hitendra S

    2009-01-01

    The development and validation of a column high-performance liquid chromatographic assay method for the determination of aspirin and clopidogrel in tablet formulation are described. The combination formulation was subjected to International Conference on Harmonization-recommended stress conditions. Separation of the drugs from the degradation products formed under stress conditions was achieved on an octasilyl (C8) column using 0.3% orthophosphoric acid-acetonitrile (65 + 35, v/v) mobile phase. The method was validated for specificity, linearity, limits of detection and quantification, precision, accuracy, and robustness. The method was found to be specific against placebo interference and during the forced degradation. The response was linear in the concentration range of 30.0-120.0 microg/mL for aspirin and 15.0-60.0 microg/mL for clopidogrel, with a correlation coefficient of 0.9999 for both. The relative standard deviation values for intra- and interday precision were aspirin and 98.20 and 100.35% for clopidogrel. Stress testing showed degradation products that were well-separated from the parent compound, confirming the stability-indicating capacity of the method.

  1. Determination of maximal amount of minor gases adsorbed in a shale sample by headspace gas chromatography.

    Science.gov (United States)

    Zhang, Chun-Yun; Hu, Hui-Chao; Chai, Xin-Sheng; Pan, Lei; Xiao, Xian-Ming

    2014-02-07

    In this paper, we present a novel method for determining the maximal amount of ethane, a minor gas species, adsorbed in a shale sample. The method is based on the time-dependent release of ethane from shale samples measured by headspace gas chromatography (HS-GC). The study includes a mathematical model for fitting the experimental data, calculating the maximal amount gas adsorbed, and predicting results at other temperatures. The method is a more efficient alternative to the isothermal adsorption method that is in widespread use today. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Novel polyamide-based nanofibers prepared by electrospinning technique for headspace solid-phase microextraction of phenol and chlorophenols from environmental samples

    Energy Technology Data Exchange (ETDEWEB)

    Bagheri, Habib, E-mail: bagheri@sharif.edu [Environmental and Bio-Analytical Laboratories, Department of Chemistry, Sharif University of Technology, Azadi Av., P.O. Box 11365-9516, Tehran (Iran, Islamic Republic of); Aghakhani, Ali; Baghernejad, Masoud; Akbarinejad, Alireza [Environmental and Bio-Analytical Laboratories, Department of Chemistry, Sharif University of Technology, Azadi Av., P.O. Box 11365-9516, Tehran (Iran, Islamic Republic of)

    2012-02-24

    A novel solid phase microextraction (SPME) fiber was fabricated by electrospinning method in which a polymeric solution was converted to nanofibers using high voltages. A thin stainless steel wire was coated by the network of polymeric nanofibers. The polymeric nanofiber coating on the wire was mechanically stable due to the fine and continuous nanofibers formation around the wire with a three dimensional structure. Polyamide (nylon 6), due to its suitable characteristics was used to prepare the unbreakable SPME nanofiber. The scanning electron microscopy (SEM) images of this new coating showed a diameter range of 100-200 nm for polyamide nanofibers with a homogeneous and porous surface structure. The extraction efficiency of new coating was investigated for headspace solid-phase microextraction (HS-SPME) of some environmentally important chlorophenols from aqueous samples followed by gas chromatography-mass spectrometry (GC-MS) analysis. Effect of different parameters influencing the extraction efficiency including extraction temperature, extraction time, ionic strength and polyamide amount were investigated and optimized. In order to improve the chromatographic behavior of phenolic compounds, all the analytes were derivatized prior to the extraction process using basic acetic anhydride. The detection limits of the method under optimized conditions were in the range of 2-10 ng L{sup -1}. The relative standard deviations (RSD) (n = 3) at the concentration level of 1.7-6.7 ng mL{sup -1} were obtained between 1 and 7.4%. The calibration curves of chlorophenols showed linearity in the range of 27-1330 ng L{sup -1} for phenol and monochlorophenols and 7-1000 ng L{sup -1} for dichloro and trichlorophenols. Also, the proposed method was successfully applied to the extraction of phenol and chlorophenols from real water samples and relative recoveries were between 84 and 98% for all the selected analytes except for 2,4,6 tricholophenol which was between 72 and 74%.

  3. Application of a space-time CE/SE (Conversation Element/Solution Element) method to the numerical solution of chromatographic separation processes

    DEFF Research Database (Denmark)

    For solving partial differential equations (or distributed dynamic systems), the method of lines (MOL) and the space-time conservation element and solution element (CE/SE) method are compared in terms of computational efficiency, solution accuracy and stability. Several representative examples....... It is concluded that the CE/SE method is adequate to capturing shocks in PDEs but for diffusion-dominated stiff PDEs, the MOL with an ODE time integrator is complementary to the CE/SE method....

  4. Referred Air Method 25E: Determination of a Vapor Phase Organic Concentration in Waste Samples

    Science.gov (United States)

    This method is applicable for determining the vapor pressure of waste. The headspace vapor of the sample is analyzed for carbon content by a headspace analyzer, which uses a flame ionization detector (FID).

  5. Green ultra-fast high-performance liquid chromatographic method using a short narrow-bore column packed with fully porous sub-2 μm particles for the simultaneous determination of selected pharmaceuticals as surface water and wastewater pollutants.

    Science.gov (United States)

    Shaaban, Heba; Górecki, Tadeusz

    2013-01-01

    Fast separations are very desirable in laboratories that analyze large numbers of samples per day or those needing short turn-around times. Traditional HPLC methods using conventional stationary phases and standard column dimensions require significant amounts of organic solvents and generate large volumes of waste. With growing awareness about the environment, the development of green technologies has been receiving increasing attention. In this work, a very fast green analytical method based on LC-UV using a short narrow bore column packed with fully porous sub-2 μm particles has been developed for simultaneous determination of nine pharmaceuticals in wastewater and surface water. The chromatographic separation was optimized in order to achieve short analysis time and good resolution for all analytes in a single run. All analytes could be separated in 1 min with good resolution. Sample preparation was executed by solid phase extraction using Oasis HLB cartridges. The method developed was validated based on parameters such as linearity, precision, accuracy, detection, and quantification limits. The recovery ranged from 70.9 to 92.5% with SDs not higher than 5.4%, except for acetaminophen and sulphanilamide. LODs ranged from 0.6-2.5 μg/L, while the LOQs were in the range 2-8 μg/L. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Headspace Gosford data: The local application of a National model.

    Science.gov (United States)

    Howe, Deborah; Coates, Dominiek; Batchelor, Samantha

    2014-08-01

    Despite the high prevalence of mental health problems for young Australians, many do not have ready access to treatment or are reluctant to seek help. Until recently there was a tendency for young Australians to fall between the gap of Child and Adolescent Mental Health Services and Adult Mental Health Services, and this has contributed to low rates of service use for young people. In 2006, the Australian Government sought to redress this gap in service delivery with its establishment of the Australian National Youth Mental Health Foundation, headspace. This paper presents demographic data collected at headspace Gosford over a 5.5-year period. The data presented indicates that headspace Gosford has been successful in improving early access to mental health treatment for young people on the Central Coast, in particular for young people aged 14-18. Headspace Gosford has attracted young people of both sexes, with a higher proportion of females. The majority of young people access headspace for mental health problems, predominantly depression and anxiety; however, a significant proportion report physical health or alcohol and drug-related reasons. The likelihood of these referral reasons is informed by gender and age. © The Royal Australian and New Zealand College of Psychiatrists 2014.

  7. Rapid quantitative detection of glucose content in glucose injection by reaction headspace gas chromatography.

    Science.gov (United States)

    Xie, Wei-Qi; Gong, Yi-Xian; Yu, Kong-Xian

    2017-10-20

    This work investigates an automated technique for rapid detecting the glucose content in glucose injection by reaction headspace gas chromatography (HS-GC). This method is based on the oxidation reaction of glucose in glucose injection with potassium dichromate. The carbon dioxide (CO 2 ) formed from the oxidation reaction can be quantitatively detected by GC. The results show that the relative standard deviation (RSD) of the present method was within 2.91%, and the measured glucose contents in glucose injection closely match those quantified by the reference method (relative differences glucose content in glucose injection related applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Determination of ketone bodies in blood by headspace gas chromatography-mass spectrometry

    DEFF Research Database (Denmark)

    Holm, Karen Marie Dollerup; Linnet, Kristian; Rasmussen, Brian Schou

    2010-01-01

    A gas chromatography-mass spectrometry (GC-MS) method for determination of ketone bodies (ß-hydroxybutyrate, acetone, and acetoacetate) in blood is presented. The method is based on enzymatic oxidation of D-ß-hydroxybutyrate to acetoacetate, followed by decarboxylation to acetone, which...... was quantified by the use of headspace GC-MS using acetone-(13)C(3) as an internal standard. The developed method was found to have intra- and total interday relative standard deviations acetone+acetoacetate levels (~25 to 8300 µM) and D-ß-hydroxybutyrate levels (~30 to 16500 µM). Recovery values varied...

  9. Multi-criteria decision making development of ion chromatographic method for determination of inorganic anions in oilfield waters based on artificial neural networks retention model.

    Science.gov (United States)

    Stefanović, Stefica Cerjan; Bolanča, Tomislav; Luša, Melita; Ukić, Sime; Rogošić, Marko

    2012-02-24

    This paper describes the development of ad hoc methodology for determination of inorganic anions in oilfield water, since their composition often significantly differs from the average (concentration of components and/or matrix). Therefore, fast and reliable method development has to be performed in order to ensure the monitoring of desired properties under new conditions. The method development was based on computer assisted multi-criteria decision making strategy. The used criteria were: maximal value of objective functions used, maximal robustness of the separation method, minimal analysis time, and maximal retention distance between two nearest components. Artificial neural networks were used for modeling of anion retention. The reliability of developed method was extensively tested by the validation of performance characteristics. Based on validation results, the developed method shows satisfactory performance characteristics, proving the successful application of computer assisted methodology in the described case study. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Influence of peak-broadening and interdetector volume error on size-exclusive chromatographic analysis with dual viscometric-concentration detection using the universal calibration method.

    Science.gov (United States)

    Netopilík, M

    2001-04-27

    The effect of peak-broadening and error in interdetector volume on the local calibration curve and experimental molecular-mass averages obtained by size-exclusion chromatography (SEC) with dual concentration/viscosity detection, and determination of molecular mass using the universal calibration (UC) method, is theoretically examined using a polymer sample with a molecular-mass distribution (MMD) approximated by the log-normal function. Although peak-broadening is often neglected, its effect on the slope of the local calibration curve and, consequently, on the experimentally obtained values of the weight-to-number average ratio is large. To obtain the right values of these parameters, a numerical correction is usually recommended. While using the UC method, the relationships between the extent of peak broadening, calibration slopes and interdetector volume are complex and can contribute to the occurrence of undiscovered errors. For this reason, an understanding of this problem, using a model, is necessary. The results of the UC method are compared with those obtained using dual-detection with known Mark-Houwink-Kuhn-Sakurada parameters (MHKS method), light-scattering (LS)/concentration detection as well as with the results obtained using conventional calibration. Due to peak-broadening, the slope of a local calibration curve and the weight-to-number average ratio, (Mw/Mn)", obtained using the UC method, increase compared to the theoretical values, whereas they decrease using the MHKS or LS methods. The increase when using the UC method is even larger compared to evaluation using conventional calibration. The effect of the error in interdetector volume on the slopes of local calibrations and the weight-to-number average ratios is opposite in the UC method to that found using the MHKS and LS methods.

  11. Solvent-assisted headspace sampling using solid phase microextraction for the analysis of phenols in water.

    Science.gov (United States)

    George, Mosotho J; Marjanovic, Ljiljana; Williams, D Bradley G

    2015-10-06

    Headspace analysis is used widely and relies on volatilization of analytes into the headspace above the matrix. We detail the dramatic influence that added solvent can have on headspace analysis of phenols, without the requirement for specialized headspace vials. The use of water-immiscible solvents is key and leads to a 1-3 orders of magnitude enhancement in the volatilization of these analytes and shorter fiber exposure times than are otherwise required.

  12. Performance Demonstration Program Plan for Analysis of Simulated Headspace Gases

    Energy Technology Data Exchange (ETDEWEB)

    Carlsbad Field Office

    2006-04-01

    The Performance Demonstration Program (PDP) for headspace gases distributes sample gases of volatile organic compounds (VOCs) for analysis. Participating measurement facilities (i.e., fixed laboratories, mobile analysis systems, and on-line analytical systems) are located across the United States. Each sample distribution is termed a PDP cycle. These evaluation cycles provide an objective measure of the reliability of measurements performed for transuranic (TRU) waste characterization. The primary documents governing the conduct of the PDP are the Quality Assurance Program Document (QAPD) (DOE/CBFO-94-1012) and the Waste Isolation Pilot Plant (WIPP) Waste Analysis Plan (WAP) contained in the Hazardous Waste Facility Permit (NM4890139088-TSDF) issued by the New Mexico Environment Department (NMED). The WAP requires participation in the PDP; the PDP must comply with the QAPD and the WAP. This plan implements the general requirements of the QAPD and the applicable requirements of the WAP for the Headspace Gas (HSG) PDP. Participating measurement facilities analyze blind audit samples of simulated TRU waste package headspace gases according to the criteria set by this PDP Plan. Blind audit samples (hereafter referred to as PDP samples) are used as an independent means to assess each measurement facility’s compliance with the WAP quality assurance objectives (QAOs). To the extent possible, the concentrations of VOC analytes in the PDP samples encompass the range of concentrations anticipated in actual TRU waste package headspace gas samples. Analyses of headspace gases are required by the WIPP to demonstrate compliance with regulatory requirements. These analyses must be performed by measurement facilities that have demonstrated acceptable performance in this PDP. These analyses are referred to as WIPP analyses and the TRU waste package headspace gas samples on which they are performed are referred to as WIPP samples in this document. Participating measurement

  13. Performance Demonstration Program Plan for Analysis of Simulated Headspace Gases

    Energy Technology Data Exchange (ETDEWEB)

    Carlsbad Field Office

    2007-11-13

    The Performance Demonstration Program (PDP) for headspace gases distributes blind audit samples in a gas matrix for analysis of volatile organic compounds (VOCs). Participating measurement facilities (i.e., fixed laboratories, mobile analysis systems, and on-line analytical systems) are located across the United States. Each sample distribution is termed a PDP cycle. These evaluation cycles provide an objective measure of the reliability of measurements performed for transuranic (TRU) waste characterization. The primary documents governing the conduct of the PDP are the Quality Assurance Program Document (QAPD) (DOE/CBFO-94-1012) and the Waste Isolation Pilot Plant (WIPP) Waste Analysis Plan (WAP) contained in the Hazardous Waste Facility Permit (NM4890139088-TSDF) issued by the New Mexico Environment Department (NMED). The WAP requires participation in the PDP; the PDP must comply with the QAPD and the WAP. This plan implements the general requirements of the QAPD and the applicable requirements of the WAP for the Headspace Gas (HSG) PDP. Participating measurement facilities analyze blind audit samples of simulated TRU waste package headspace gases according to the criteria set by this PDP Plan. Blind audit samples (hereafter referred to as PDP samples) are used as an independent means to assess each measurement facility’s compliance with the WAP quality assurance objectives (QAOs). To the extent possible, the concentrations of VOC analytes in the PDP samples encompass the range of concentrations anticipated in actual TRU waste package headspace gas samples. Analyses of headspace gases are required by the WIPP to demonstrate compliance with regulatory requirements. These analyses must be performed by measurement facilities that have demonstrated acceptable performance in this PDP. These analyses are referred to as WIPP analyses and the TRU waste package headspace gas samples on which they are performed are referred to as WIPP samples in this document

  14. Performance Demonstration Program Plan for Analysis of Simulated Headspace Gases

    Energy Technology Data Exchange (ETDEWEB)

    Carlsbad Field Office

    2007-11-19

    The Performance Demonstration Program (PDP) for headspace gases distributes blind audit samples in a gas matrix for analysis of volatile organic compounds (VOCs). Participating measurement facilities (i.e., fixed laboratories, mobile analysis systems, and on-line analytical systems) are located across the United States. Each sample distribution is termed a PDP cycle. These evaluation cycles provide an objective measure of the reliability of measurements performed for transuranic (TRU) waste characterization. The primary documents governing the conduct of the PDP are the Quality Assurance Program Document (QAPD) (DOE/CBFO-94-1012) and the Waste Isolation Pilot Plant (WIPP) Waste Analysis Plan (WAP) contained in the Hazardous Waste Facility Permit (NM4890139088-TSDF) issued by the New Mexico Environment Department (NMED). The WAP requires participation in the PDP; the PDP must comply with the QAPD and the WAP. This plan implements the general requirements of the QAPD and the applicable requirements of the WAP for the Headspace Gas (HSG) PDP. Participating measurement facilities analyze blind audit samples of simulated TRU waste package headspace gases according to the criteria set by this PDP Plan. Blind audit samples (hereafter referred to as PDP samples) are used as an independent means to assess each measurement facility’s compliance with the WAP quality assurance objectives (QAOs). To the extent possible, the concentrations of VOC analytes in the PDP samples encompass the range of concentrations anticipated in actual TRU waste package headspace gas samples. Analyses of headspace gases are required by the WIPP to demonstrate compliance with regulatory requirements. These analyses must be performed by measurement facilities that have demonstrated acceptable performance in this PDP. These analyses are referred to as WIPP analyses and the TRU waste package headspace gas samples on which they are performed are referred to as WIPP samples in this document

  15. A quantitative structure- property relationship of gas chromatographic/mass spectrometric retention data of 85 volatile organic compounds as air pollutant materials by multivariate methods.

    Science.gov (United States)

    Sarkhosh, Maryam; Ghasemi, Jahan B; Ayati, Mahnaz

    2012-05-02

    A quantitative structure-property relationship (QSPR) study is suggested for the prediction of retention times of volatile organic compounds. Various kinds of molecular descriptors were calculated to represent the molecular structure of compounds. Modeling of retention times of these compounds as a function of the theoretically derived descriptors was established by multiple linear regression (MLR) and artificial neural network (ANN). The stepwise regression was used for the selection of the variables which gives the best-fitted models. After variable selection ANN, MLR methods were used with leave-one-out cross validation for building the regression models. The prediction results are in very good agreement with the experimental values. MLR as the linear regression method shows good ability in the prediction of the retention times of the prediction set. This provided a new and effective method for predicting the chromatography retention index for the volatile organic compounds.

  16. A quantitative structure- property relationship of gas chromatographic/mass spectrometric retention data of 85 volatile organic compounds as air pollutant materials by multivariate methods

    Directory of Open Access Journals (Sweden)

    Sarkhosh Maryam

    2012-05-01

    Full Text Available Abstract A quantitative structure-property relationship (QSPR study is suggested for the prediction of retention times of volatile organic compounds. Various kinds of molecular descriptors were calculated to represent the molecular structure of compounds. Modeling of retention times of these compounds as a function of the theoretically derived descriptors was established by multiple linear regression (MLR and artificial neural network (ANN. The stepwise regression was used for the selection of the variables which gives the best-fitted models. After variable selection ANN, MLR methods were used with leave-one-out cross validation for building the regression models. The prediction results are in very good agreement with the experimental values. MLR as the linear regression method shows good ability in the prediction of the retention times of the prediction set. This provided a new and effective method for predicting the chromatography retention index for the volatile organic compounds.

  17. Chromatographic and electrophoretic approaches in ink analysis.

    Science.gov (United States)

    Zlotnick, J A; Smith, F P

    1999-10-15

    Inks are manufactured from a wide variety of substances that exhibit very different chemical behaviors. Inks designed for use in different writing instruments or printing methods have quite dissimilar components. Since the 1950s chromatographic and electrophoretic methods have played important roles in the analysis of inks, where compositional information may have bearing on the investigation of counterfeiting, fraud, forgery, and other crimes. Techniques such as paper chromatography and electrophoresis, thin-layer chromatography, high-performance liquid chromatography, gas chromatography, gel electrophoresis, and the relatively new technique of capillary electrophoresis have all been explored as possible avenues for the separation of components of inks. This paper reviews the components of different types of inks and applications of the above separation methods are reviewed.

  18. Bioanalytical chromatographic method validation according to current regulations, with a special focus on the non-well defined parameters limit of quantification, robustness and matrix effect.

    Science.gov (United States)

    González, Oskar; Blanco, María Encarnación; Iriarte, Gorka; Bartolomé, Luis; Maguregui, Miren Itxaso; Alonso, Rosa M

    2014-08-01

    Method validation is a mandatory step in bioanalysis, to evaluate the ability of developed methods in providing reliable results for their routine application. Even if some organisations have developed guidelines to define the different parameters to be included in method validation (FDA, EMA); there are still some ambiguous concepts in validation criteria and methodology that need to be clarified. The methodology to calculate fundamental parameters such as the limit of quantification has been defined in several ways without reaching a harmonised definition, which can lead to very different values depending on the applied criterion. Other parameters such as robustness or ruggedness are usually omitted and when defined there is not an established approach to evaluate them. Especially significant is the case of the matrix effect evaluation which is one of the most critical points to be studied in LC-MS methods but has been traditionally overlooked. Due to the increasing importance of bioanalysis this scenario is no longer acceptable and harmonised criteria involving all the concerned parties should be arisen. The objective of this review is thus to discuss and highlight several essential aspects of method validation, focused in bioanalysis. The overall validation process including common validation parameters (selectivity, linearity range, precision, accuracy, stability…) will be reviewed. Furthermore, the most controversial parameters (limit of quantification, robustness and matrix effect) will be carefully studied and the definitions and methodology proposed by the different regulatory bodies will be compared. This review aims to clarify the methodology to be followed in bioanalytical method validation, facilitating this time consuming step. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Simultaneous Determination of Impurities of Atazanavir and Ritonavir in Tablet Dosage Form by Using Reversed-Phase Ultra Performance Liquid Chromatographic Method.

    Science.gov (United States)

    Mantripragada, Murali Krishna V V N; Rao, Sumathi V; Nutulapati, Venugopal V S; Mantena, Bhaskara P V

    2017-12-29

    A simple, rapid, selective and stability indicating reversed phase-ultra performance liquid chromatography method was developed and validated for the simultaneous quantification of process related and degradation impurities present in Atazanavir and Ritonavir tablets. The two proposed drug components and their respective impurities were separated using Acquity BEH C18 (100 mm × 2.1 mm), 1.7 μ column at a flow rate of 0.4 mL/min. Buffer used as Mobile phase-A which consists of 0.01 M monobasic potassium hydrogen phosphate adjusted the pH to 3.6 and acetonitrile is used as organic modifier (mobile phase-B). The detector wavelength of 240 nm was used for quantifying the impurities. Both the drug components along with their impurities were eluted within a runtime of 18 min. The performance of the developed method was checked by validating the method according to the requirements of International Conference on Harmonization for parameters such as specificity, precision, linearity, ruggedness, accuracy, sensitivity (limit of detection (LOD) and limit of quantitation (LOQ)) and robustness. Linearity and range were established from LOQ level to 150% level. Accuracy of the method was demonstrated from LOQ level to 150% level. The developed stability indicating method is capable for determination of impurities of Atazanavir and Ritonavir in combined tablet dosage form as well as individual dosage forms also. The reported method enables lesser solvent consumption and reduces time and cost of the analysis in quality control laboratory. © The Author(s) 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Two multidimensional chromatographic methods for enantiomeric analysis of o,p'-DDT and o,p'-DDD in contaminated soil and air in a malaria area of South Africa.

    Science.gov (United States)

    Naudé, Yvette; Rohwer, Egmont R

    2012-06-12

    In rural parts of South Africa the organochlorine insecticide DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) is still used for malaria vector control where traditional dwellings are sprayed on the inside with small quantities of technical DDT. Since o,p'-DDT may show enantioselective oestrogenicity and biodegradability, it is important to analyse enantiomers of o,p'-DDT and its chiral degradation product, o,p'-DDD, for both health and environmental-forensic considerations. Generally, chiral analysis is performed using heart-cut multidimensional gas chromatography (MDGC) and, more recently, comprehensive two-dimensional gas chromatography (GC×GC). We developed an off-line gas chromatographic fraction collection (heart-cut) procedure for the selective capturing of the appropriate isomers from a first apolar column, followed by reinjection and separation on a second chiral column. Only the o,p'-isomers of DDT and DDD fractions from the first dimension complex chromatogram (achiral apolar GC column separation) were selectively collected onto a polydimethylsiloxane (PDMS) multichannel open tubular silicone rubber trap by simply placing the latter device on the flame tip of an inactivated flame ionisation detector (FID). The multichannel trap containing the o,p'-heart-cuts was then thermally desorbed into a GC with time-of-flight mass spectrometry detection (GC-TOFMS) for second dimension enantioselective separation on a chiral column (β-cyclodextrin-based). By selectively capturing only the o,p'-isomers from the complex sample chromatogram, (1)D separation of ultra-trace level enantiomers could be achieved on the second chiral column without matrix interference. Here, we present solventless concentration techniques for extraction of DDT from contaminated soil and air, and report enantiomeric fraction (EF) values of o,p'-DDT and o,p'-DDD obtained by a new multidimensional approach for heart-cut gas chromatographic fraction collection for off-line second dimension

  1. A volatile tracer-assisted headspace analytical technique for determining the swelling capacity of superabsorbent polymers.

    Science.gov (United States)

    Zhang, Shu-Xin; Jiang, Ran; Chai, Xin-Sheng

    2017-09-01

    This paper reports on a new method for the determination of swelling capacity of superabsorbent polymers by a volatile tracer-assisted headspace gas chromatography (HS-GC). Toluene was used as a tracer and added to the solution for polymers swelling test. Based on the differences of the tracer partitioned between the vapor and hydrogel phase before and after the polymer's swelling capacity, a transition point (corresponding to the material swelling capacity) can be observed when plotting the GC signal of toluene vs. the ratio of solution added to polymers. The present method has good precision (RSDpolymers at the elevated temperatures. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. A comparison of the extraction procedures and quantification methods for the chromatographic determination of polycyclic aromatic hydrocarbons in charcoal grilled meat and fish.

    Science.gov (United States)

    Viegas, O; Novo, P; Pinho, O; Ferreira, I M P L V O

    2012-01-15

    A method for analysis of 15 PAHs in charcoal-grilled meat/fish was established by high performance liquid chromatography and fluorescence detection. Gradient elution was performed with methanol/water/ethyl acetate. Maxima excitation and emission wavelengths were selected for each PAH. Retention times were very stable with coefficients of variation below 0.24% within analytical day and below 0.60% across analytical days. Two different methods of cleanup and pre-concentration steps were compared. Solvent extraction assisted by sonication carried out with n-hexane on 2g of lyophilized meat or 1g of lyophilized fish allowed to obtain high sensitivity, reproducibility and better extraction efficiency. Limits of quantification (LOQs, s/n=10) were lower than 0.01ng/g of meat wet weight and lower than 0.02ng/g of fish wet weight for all PAHs (except for Na, Fl and IP that were lower than 0.1ng/g). Two different quantification methods were compared. Standard addition method compensated PAHs losses due to incomplete extraction and it is recommended for analyses of grilled meat and fish samples that usually contain very low amounts of the eight high molecular weight PAHs (BaA, Ch, BbF, BkF, BaP, IP, BgP, DhA). Copyright © 2011 Elsevier B.V. All rights reserved.

  3. Development and application of a reversed-phase high-performance liquid chromatographic method for quantitation and characterization of a Chikungunya virus-like particle vaccine.

    Science.gov (United States)

    Shytuhina, Anastasija; Pristatsky, Pavlo; He, Jian; Casimiro, Danilo R; Schwartz, Richard M; Hoang, Van M; Ha, Sha

    2014-10-17

    To effectively support the development of a Chikungunya (CHIKV) virus-like particle (VLP) vaccine, a sensitive and robust high-performance liquid chromatography (HPLC) method that can quantitate CHIKV VLPs and monitor product purity throughout the manufacturing process is needed. We developed a sensitive reversed-phase HPLC (RP-HPLC) method that separates capsid, E1, and E2 proteins in CHIKV VLP vaccine with good resolution. Each protein component was verified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-ToF) mass spectrometry (MS). The post-translational modifications on the viral glycoproteins E1 and E2 were further identified by intact protein mass measurements with liquid chromatography-mass spectrometry (LC-MS). The RP-HPLC method has a linear range of 0.51-12 μg protein, an accuracy of 96-106% and a precision of 12% RSD, suitable for vaccine product release testing. In addition, we demonstrated that the RP-HPLC method is useful for characterizing viral glycoprotein post-translational modifications, monitoring product purity during process development and assessing product stability during formulation development. Published by Elsevier B.V.

  4. Testing the suitability of different high-performance liquid chromatographic methods to determine aflatoxin M1 in a soft fresh Italian cheese.

    Science.gov (United States)

    Cattaneo, T M P; Marinoni, L; Barzaghi, S; Cremonesi, K; Monti, L

    2011-07-22

    Aflatoxin M1 (AFM1) is a toxic undesirable compound in milk. AFM1 affinity for caseins causes a concentration effect during milk process for dairy transformation. In spite of this, no official method of analysis, nor maximum tolerance level for aflatoxin M1 in cheese have been established. Thus, the aim of this work was to test the suitability of different HPLC methods for the AFM1 quantification in soft cheese samples at three different contamination levels (low, medium and high, at respectively nearly 30, 100 and 250 ng/kg). Nine participants were selected among Italian laboratories accredited by the Italian accreditation body (ACCREDIA) for HPLC toxin analysis. They were asked to analyze samples applying the method routinely used. The different applied methods were compared, and precision and accuracy parameters were evaluated. The main differences among HPLC procedures were registered at the level of extraction step. The use of an enzymatic digestion for the extraction of the toxin from cheese seemed to be particularly advantageous and the use of immunoaffinity columns seemed to be determinant for the improvement of sensitivity at low contamination levels. In general, the applied methods well discriminated the 3 levels of contamination, even though they performed better at the medium and high concentration levels (100 and 250 ng/kg) than at the low one (30 ng/kg). In fact relative standard deviation for reproducibility at low level was higher (60.1%) than the same value at medium and high levels (22.8% and 28.9%, respectively). Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Development and validation of ultra-performance liquid chromatographic method with tandem mass spectrometry for determination of lenalidomide in rabbit and human plasma

    Directory of Open Access Journals (Sweden)

    Iqbal Muzaffar

    2013-01-01

    Full Text Available Abstract Background Lenalidomide (LND is a potent novel thalidomide analog which demonstrated remarkable clinical activity in treatment of multiple myeloma disease via a multiple-pathways mechanism. Validated sensitive method with high throughput is required for the determination of lenalidomide for pharmacokinetics and toxicokinetic studies. Ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS is a preeminent analytical tool for rapid biomedical analysis. Results A simple, highly sensitive UPLC-MS/MS method was developed and validated for the determination of LND in rabbit and human plasma. After a simple protein precipitation using methanol, LND and carbamazepine (IS were separated on Acquity UPLC BEH™ C18 column (50 × 2.1 mm, i.d. 1.7 μm, Waters, USA using a mobile phase consisted of acetonitrile:water:formic acid (65:35:0.1%, v/v/v pumped at a flow rate of 0.2 mL/min. LND and IS were eluted at 0.71 and 1.92 min, respectively. The mass spectrometric determination was carried out using an electrospray interface operated in the positive mode with multiple reaction monitoring (MRM mode. The precursor to product ion transitions of m/z 260.1 > 149.0 and m/z 237.0 > 179.0 were used to quantify LND and IS, respectively. The method was linear in the concentration range of 0.23–1000 ng/mL with a limit of quantitation of 0.23 ng/mL. All the validation parameters were in the ranges acceptable by the guidelines of analytical method validation. Conclusion The proposed UPLC-MS/MS method is simple, rapid and highly sensitive, and hence it could be reliable for pharmacokinetic and toxicokinetic study in both animals and humans.

  6. Quantity and quality of black carbon molecular markers as obtained by two chromatographic methods (GC-FID and HPLC-DAD) - How do results compare?

    Science.gov (United States)

    Schneider, M. P. W.; Smittenberg, R. H.; Dittmar, T.; Schmidt, M. W. I.

    2009-04-01

    Chars produced by wildfires are an important source of black carbon (BC) in the environment. After their deposition on the soil surface they can be distributed into rivers, marine waters and sediments. The analysis of benzenepolycarboxylic acids (BPCAs) as a quantitative measure for black carbon (BC) in soil and sediment samples is a well-established method (Glaser et al., 1998; Brodowski et al., 2005). Briefly, the nitric acid oxidation of fused aromatic ring systems in BC forms eight molecular markers (BPCAs), which can be assigned to BC, and which subsequently can be quantified by GC-FID (gas chromatography with flame ionization detector). Recently, this method was modified for the quantification of BC in seawater samples using HPLC-DAD (High performance liquid chromatography with diode array detector) for the determination of individual BPCAs (Dittmar, 2008). A direct comparison of both analytical techniques is lacking but would be important for future data comparison aimed at the calculation of global BC budgets. Here we present a systematic comparison of the two BPCA quantification methods. We prepared chars under well-defined laboratory conditions. In order to cover a broad spectrum of char properties we used two sources of biomass and a wide range of pyrolysis temperatures. Chestnut hardwood chips (Castanea sativa) and rice straw (Oryza sativa) were pyrolysed at temperatures between 200 and 1000°C under a constant N2 stream. The maximum temperatures were held constant for 5 hours (Hammes et al., 2006). The BC contents of the chars have been analysed using the BPCA extraction method followed by either GC-FID or HPLC-DAD quantification. Preliminary results suggest that both methods yield similar total quantities of BPCA, and also the proportions of the individual markers are similar. Ongoing experiments will allow for a more detailed comparison of the two methods. The BPCA composition of chars formed at different temperatures and from different precursor

  7. Tank 241-BX-104 fourth temporal study: Headspace gas and vapor characterization results from samples collected on April 7, 1997. Tank vapor characterization project

    Energy Technology Data Exchange (ETDEWEB)

    Mitroshkov, A.V.; Hayes, J.C.; Evans, J.C. [and others

    1997-09-01

    This report presents the results from analyses of samples taken from the headspace of waste storage tank 241-BX-04 (Tank BX-104) at the Hanford Site in Washington State. Tank headspace samples collected by SGN Eurisys Service Corporation (SESC) were analyzed by Pacific Northwest National Laboratory (PNNL) to determine headspace concentrations of selected non-radioactive analytes. Analyses were performed by the Vapor Analytical Laboratory (VAL) at PNNL. Vapor concentrations from sorbent trap samples are based on measured sample volumes provided by SESC. Ammonia was determined to be above the immediate notification limit specified by the sampling and analysis plan (SAP). Hydrogen was the principal flammable constituent of the Tank BX-104 headspace, determined to be present at approximately 0.208% of its lower flammability limit (LFL). Total headspace flammability was estimated to be <0.536% of the LFL. Average measured concentrations of targeted gases, inorganic vapors, and selected organic vapors are provided in Table S.1. A summary of experimental methods, including sampling methodology, analytical procedures, and quality assurance and control methods are presented in Section 2.0. Detailed descriptions of the analytical results are provided in Section 3.0.

  8. Tank Vapor Characterization Project: Tank 241-BX-106 headspace gas and vapor characterization results from samples collected on August 15, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Pool, K.H.; Evans, J.C.; Thomas, B.L.; Edwards, J.A.; Julya, J.L. [and others

    1997-08-01

    This report presents the results from analyses of samples taken from the headspace of waste storage tank 241-BX-106 (Tank BX-106) at the Hanford Site in Washington State. Tank headspace samples collected by Westinghouse Hanford Company (WHC) were analyzed by Pacific Northwest National Laboratory (PNNL) to determine headspace concentrations of selected non-radioactive analytes. Analyses were performed by the Vapor Analytical Laboratory (VAL) at PNNL. Vapor concentrations from sorbent trap samples are based on measured sample volumes provided by WHC. No analytes were determined to be above the immediate notification limits specified by the sampling and analysis plan. Ammonia was the principal flammable constituent of the Tank BX-106 headspace, determined to be present at approximately 0.031% of it lower flammability limit (LFL). Total headspace flammability was estimated to be <0.143% of the LFL. Average measured concentrations of targeted gases, inorganic vapors, and selected organic vapors are provided in Table S.1. A summary of experimental methods, including sampling methodology, analytical procedures, and quality assurance and control methods are presented in Section 2.0. Detailed descriptions of the analytical results are provided in Section 3.0.

  9. Tank 241-BY-108 fourth temporal study: Headspace gas and vapor characterization results from samples collected on November 14, 1997. Tank vapor characterization project

    Energy Technology Data Exchange (ETDEWEB)

    Evans, J.C.; Pool, K.H.; Olsen, K.B. [and others

    1997-07-01

    This report presents the results from analyses of samples taken from the headspace of waste storage tank 241-BY-108 (Tank BY-108) at the Hanford Site in Washington State. Tank headspace samples collected by SGN Eurisys Service Corporation (SESC) were analyzed by Pacific Northwest National Laboratory (PNNL) to determine headspace concentrations of selected nonradioactive analytes. Analyses were performed by the Vapor Analytical Laboratory (VAL) at PNNL. Vapor concentrations from sorbent trap samples are based on measured sample volumes provided by SESC. Ammonia was determined to be above the immediate notification limit of 150 ppm specified by the sampling and analysis plan (SAP). Hydrogen was the principal flammable constituent of the Tank BY-108 headspace, determined to be present at approximately 1.390% of its lower flammability limit (LFL). Total headspace flammability was estimated to be <2.830% of the LFL. Average measured concentrations of targeted gases, inorganic vapors, and selected organic vapors are provided in Table S.1. A summary of experimental methods, including sampling methodology, analytical procedures, and quality assurance and control methods are presented in Section 2.0. Detailed descriptions of the analytical results are provided in Section 3.0.

  10. Application of headspace solid-phase microextraction followed by gas chromatography coupled with mass spectrometry to determine esters of carboxylic acids and other volatile compounds in Dermestes maculatus and Dermestes ater lipids.

    Science.gov (United States)

    Cerkowniak, Magdalena; Boguś, Mieczysława I; Włóka, Emilia; Stepnowski, Piotr; Gołębiowski, Marek

    2017-07-19

    A constant problem in veterinary medicine, human healthcare, agriculture, forestry and horticulture is the large number of pests, and the lack of effective methods to combat them which cause no harm to the rest of the environment. It is recommended and desired to reduce the use of chemicals and increase the use of agents based on knowledge acquired in the fields of biology, chemistry and agrochemicals. To learn the defense mechanisms of insects we should consider not only the site of their physiological ability to protect against external factors (cuticle), but also the possibility of chemical protection, formed by all compounds on the surface and in the body of insects. In this study, a procedure was developed to determine the esters of carboxylic acids in insect lipids. Headspace solid-phase microextraction was followed by gas chromatography coupled with gas spectrometry. First, the best conditions were selected for the analysis to obtain the best chromatographic separation. An RTx-5 column was used for this purpose. Polydimethylsiloxane/divinylbenzene (PDMS/DVB) and polyacrylate fibers were used to isolate acid esters. PDMS/DVB fiber achieved the best conditions for the extraction; the extraction time was 50 min, the extraction temperature was 105°C and the desorption time was 10 min at 230°C. These solid-phase microextraction conditions were used to analyze volatile compounds extracted from insects belonging to the Dermestidae family. Copyright © 2017 John Wiley & Sons, Ltd.

  11. High-performance thin-layer chromatographic methods in the evaluation of the antioxidant and anti-hyperglycemic activity of Myrmecodia platytyrea as a promising opportunity in diabetes treatment.

    Science.gov (United States)

    Agatonovic-Kustrin, S; Morton, D W; Adam, A; Mizaton, H H; Zakaria, H

    2017-12-29

    The steady increase of diabetes is becoming a major burden on health care systems. As diabetic complications arise from oxidative stress, an antioxidant therapy along with anti-diabetic drugs is recommended. Myrmecodia or ant plant is highly valued as a traditional medicine in West Papua. It is used as an alternative treatment for diabetes, as the substances produced by ants can reduce blood sugar levels. The aim of this study was to develop and establish high-performance thin-layer chromatographic (HPTLC)-bioautographic methods to measure the antioxidant and hypoglycemic effects in different extracts from Myrmecodia platytyrea and to compare them with sterol content. Antioxidant activity in methanol, ethanol, dichloromethane (DCM) and ethyl acetate (EA) extracts were measured with a direct HPTLC-2,2-diphenyl-1-picrylhydrazyl free radical (DPPH) assay, while hypoglycemic effects were assessed using a newly developed α-amylase inhibitory activity assay. Stigmasterol is observed, after derivatization with anisaldehyde, as purple colored zones under visible light at hRF values of 0.66. The highest antioxidant activity was observed in the ethanol extract which is rich in polyphenols and flavonoids, while the DCM extract did not show antioxidant activity, but had significant α-amylase inhibitory activity. The highest α-amylase inhibitory activity was observed in the EA and DCM extracts and was related to their stigmasterol content. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  12. A validated stability indicating high-performance liquid chromatographic method for simultaneous estimation of cefuroxime sodium and sulbactam sodium in injection dosage form

    Directory of Open Access Journals (Sweden)

    Falguni M Patel

    2012-01-01

    Full Text Available Background: A fixed dose combination of cefuroxime sodium (β lactam antibiotic and sulbactam sodium (β Lactamase inhibitor is used in ratio of 2:1 as powder for injection for the treatment of resistant lower respiratory tract and other infections. Aims: A simple, precise, and accurate ion-pair reverse-phase high-performance liquid chromatography (RP-HPLC method was developed and validated for determination of cefuroxime Na(CEF and sulbactam Na(SUL in injection. Materials and Methods: Isocratic RP-HPLC separation was achieved on an ACE C 18 column (150×4.6 mm id, 5 μm particle size using the mobile phase 0.002 M tetrabutylammonium hydroxide sulfate (TBAH in 10 mm potassium di-hydrogen phosphate buffer-acetonitrile (86:14 v/v, pH 3.7 at a flow rate of 1.0 ml/min. Results and Conclusion: The retention time of sulbactam Na and cefuroxime Na were 3.2 min and 10.2 min, respectively. The ion-pairing reagent improved the retention of highly polar sulbactam Na on reverse-phase column. The detection was performed at 210 nm. The method was validated for linearity, precision, accuracy, robustness, solution stability, and specificity. The method was validated for linearity, precision, accuracy, robustness, solution stability, and specificity. The method was linear in the concentration range of 10-100 μg/ml for cefuroxime Na and 5-50 μg/ml for sulbactam Na, with a correlation coefficient of 0.9999 and 0.9998 for the respective drugs. The intraday precision was 0.13-0.21% and 0.48-0.65%, and the interday precision was 0.32-0.81% and 0.60-0.83% for cefuroxime Na and sulbactam Na, respectively. The accuracy (recovery was found to be in the range of 98.76-100.61% and 98.99-100.30% for cefuroxime Na and sulbactam Na, respectively. The drugs were found to degrade under hydrolytic and oxidative conditions. The drugs could be effectively separated from different degradation products, and hence the method can be used for stability analysis.

  13. An improved back-flush-to-vent gas chromatographic method for determination of trace permanent gases and carbon dioxide in ultra-high purity ammonia.

    Science.gov (United States)

    Trubyanov, Maxim M; Mochalov, Georgy M; Vorotyntsev, Ilya V; Vorotyntsev, Andrey V; Suvorov, Sergey S; Smirnov, Konstantin Y; Vorotyntsev, Vladimir M

    2016-05-20

    A novel method for rapid, quantitative determination of trace permanent gases and carbon dioxide in ultra-high purity ammonia by dual-channel two-dimensional GC-PDHID is presented. An improved matrix back-flush-to-vent approach combining back-flush column switching technique with auxiliary NaHSO4 ammonia trap is described. The NaHSO4 trap prevents traces of ammonia from entering the analytical column and is shown not to affect the impurity content of the sample. The approach allows shortening the analysis time and increasing the amount of measurements without extensive maintenance of the GC-system. The performance of the configuration has been evaluated utilizing ammonia- and helium-based calibration standards. The method has been applied for the analysis of 99.9999+% ammonia purified by high-pressure distillation at the production site. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Analytical Method for the Detection of Ozone Depleting Chemicals (ODC) in Commercial Products Using a Gas Chromatograph with an Electron Capture Detector (GC-ECD)

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Richard N.; Dockendorff, Brian P.; Wright, Bob W.

    2008-08-01

    This document describes an analytical procedure that was developed for the trace level detection of residual ozone depleting chemicals (ODC) associated with the manufacture of selected commercial products. To ensure the United States meets it obligation under the Montreal Protocol, Congress enacted legislation in 1989 to impose an excise tax on electronic goods imported into the United States that were produced with banned chemicals. This procedure was developed to technically determine if residual ODC chemicals could be detected on electronic circuit boards. The analytical method utilizes a “purge and trap” technique followed by gas chromatography with electron capture detection to capture and analyze the volatile chemicals associated with the matrix. The method describes the procedure, the hardware, operating conditions, calibration, and quality control measures in sufficient detail to allow the capability to be replicated. This document corresponds to internal Standard Operating Procedure (SOP) EFL-130A, Rev 4.

  15. High-performance liquid chromatographic separation of natural and synthetic desulphoglucosinolates and their chemical validation by UV, NMR and chemical ionisation-MS methods.

    Science.gov (United States)

    Kiddle, G; Bennett, R N; Botting, N P; Davidson, N E; Robertson, A A; Wallsgrove, R M

    2001-01-01

    Methods are described for the optimised extraction, desulphation and HPLC separation of desulphoglucosinolates. These methods provide rapid separation, identification and quantitative measurements of glucosinolates extracted from Brassica napus L and related crops, of unusual glucosinolates found in crucifer weed species, and also of synthetic alkylglucosinolates. The desulphoglucosinolates used in these studies were either chemically synthesised (at least one example from each major structural class), or purified from various plant sources. Validation of the identities of the desulphoglucosinolates was by comparison of retention times with standards, and by UV, 1H- and 13C-NMR and chemical ionisation MS analysis. A list of useful species, and the specific tissues, from which high concentrations of standards can be extracted is included.

  16. Validated liquid chromatographic method and analysis of content of tilianin on several extracts obtained from Agastache mexicana and its correlation with vasorelaxant effect.

    Science.gov (United States)

    Hernández-Abreu, Oswaldo; Durán-Gómez, Liliana; Best-Brown, Roberto; Villalobos-Molina, Rafael; Rivera-Leyva, Julio; Estrada-Soto, Samuel

    2011-11-18

    To optimize the obtention of tilianin, an antihypertensive flavonoid isolated from Agastache mexicana (Lamiaceae), a medicinal plant used in Mexico for the treatment of hypertension. Also, a validated HPLC method to quantify tilianin from different extracts, obtained by several extraction methods, was developed. The aerial parts of Agastache mexicana were dried at different temperatures (22, 40, 50, 90, 100 and 180°C) and the dry material was extracted with methanol by maceration to compare the content of the active constituent tilianin in the samples. Furthermore, EtOH:H(2)O (7:3), infusion and decoction extracts were prepared from air-dried samples at room temperature to compare the content and composition of the different extraction methods. Moreover, an ex vivo vasorelaxant test on endothelium-intact aortic rat rings was conducted, in order to correlate the presence of tilianin with the activity of each extract. Higher concentration and amounts of tilianin were determined from chromatograms in the obtained methanolic extracts from plant material dried at 90, 50, 40 and 22°C, followed by 100°C; however, lower concentrations were observed in dried at 180°C and EtOH:H(2)O (7:3). It is worth to notice that methanolic extracts with higher amount of tilianin were the most potent vasorelaxant extracts, even though these extracts were less potent than carbachol, a positive control used. Finally, decoction, infusion and EtOH:H(2)O (7:3) extracts did not show any vasorelaxant effect. Results suggest that extracts with higher concentration of tilianin possess the best vasorelaxant activity, which allowed us to have a HPLC method for future quality control for this medicinal plant. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  17. Reverse phase high performance liquid chromatographic method development based on ultravioletvisible detector for the analysis of 1-hydroxypyrene (PAH biomarker) in human urine.

    Science.gov (United States)

    Kamal, Atif; Gulfraz, Mohammad; Anwar, Mohammad Asad; Malik, Riffat Naseem

    2015-01-01

    1-hydroxypyrene is an important biomarker of exposure to polycyclic aromatic hydrocarbons (PAHs), which appears in the urine of exposed human subjects. In developing countries, where advanced instruments are not available, the importance of this biomarker demands convenient and sensitive methods for determination purposes. This study aimed at developing a methodology to quantify 1-hydroxypyrene (a biomarker of PAHs exposure) based on the UV-visible detector in the reverse phase high pressure liquid chromatography (HPLC). A 20 μl injection of sample was used for manual injection into the HPLC Shimadzu, equipped with the SPD-20 A UV-visible detector, the LC-20AT pump and the DGU-20A5 degasser. The C-18 column was used for the purpose of the analysis. The method showed a good linearity (the range: R2 = 0.979-0.989), and high detectability up to the nmol level. The average retention was 6.37, with the accuracy of 2%, and the percentage of recovery remained 108%. The overall performance of this method was comparable (in terms of detection sensitivity) and relatively better than previously reported studies using the HPLC system equipped with the UV-detector. This method is suitable and reliable for the detection/quantification of the 1-OHP in human urine samples, using the UV-detector, however, it is less sensitive as compared to the results of a florescence detector. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  18. Bioanalytical development and validation of liquid chromatographic-tandem mass spectrometric methods for the quantification of total and free cefazolin in human plasma and cord blood.

    Science.gov (United States)

    Crutchfield, Christopher A; Marzinke, Mark A

    2015-04-01

    Cefazolin is a commonly prescribed β-lactam antibiotic for prophylaxis against skin infections following surgery, including caesarean sections. Assessment of maternal and neonatal exposure is important for correlating drug concentrations to clinical outcomes. Thus, bioanalytical methods for the quantification of both total and free cefazolin in maternal plasma and cord blood can assist in the comprehensive evaluation of cefazolin exposure. Specimen preparation for the measurement of total cefazolin was performed via protein precipitation with acetonitrile containing the internal standard cloxacillin. Ultrafiltration was used to isolate free cefazolin. Processed samples were analyzed on a Prelude SPLC system coupled to a TSQ triple quadrupole Vantage mass spectrometer. Methods were validated following FDA bioanalytical guidelines. The analytical measuring ranges of these methods were 0.48-480 µg/mL and 0.048-48 µg/mL for total and free drug, respectively. Calibration curves were generated using 1/x(2) weighted linear regression analysis. Total cefazolin demonstrated inter- and intra-assay precision of ≤20% at the LLOQ and ≤11.2% at other levels. Free cefazolin demonstrated inter- and intra-assay precision of ≤18.5% at the LLOQ and ≤12.6% at other levels, respectively. Accuracy (%DEV), carryover, matrix effects, recovery and stability studies were also acceptable based on FDA recommendations. Furthermore, it was demonstrated that samples prepared in cord blood can be accurately quantified from an adult plasma calibration curve, with recoveries ≤9.1% DIF and ≤11.9% DIF for total and free cefazolin, respectively. The described LC-MS/MS methods allow for the measurement of total and free cefazolin in both plasma and cord blood.

  19. Simultaneous determination of related substances of telmisartan and hydrochlorothiazide in tablet dosage form by using reversed phase high performance liquid chromatographic method

    Directory of Open Access Journals (Sweden)

    Sutirtho Mukhopadhyay

    2011-01-01

    Full Text Available Objective : Telmisartan is a potent, long-lasting, nonpeptide antagonist of the angiotensin II type-1 (AT 1 receptor that is indicated for the treatment of essential hypertension. Hydrochlorothiazide is a widely prescribed diuretic and it is indicated for the treatment of edema, control of essential hypertension and management of diabetes insipidus. In the current article a new, accurate, sensitive, precise, rapid, reversed phase high performance liquid chromatography (RP-HPLC method was developed for determination of related substances of Telmisartan and Hydrochlorthiazide in tablet dosage form. Materials and Methods : Simultaneous determination of related substances was performed on Kromasil C 18 analytical column (250 × 4.6 mm; 5΅m pertical size column at 40°C employing a gradient elution. Mobile phase consisting of solvent A (solution containing 2.0 g of potassium dihydrogen phosphate anhydrous and 1.04 g of Sodium 1- Hexane sulphonic acid monohydrate per liter of water, adjusted to pH 3.0 with orthophosphoric acid and solvent B (mixture of Acetonitrile: Methanol in the ratio 80:20 v/v was used at a flow rate of 1.0 ml min−1 . UV detection was performed at 270 nm. Results : During method validation parameter such as precision, linearity, accuracy, specificity, limit of detection and quantification were evaluated, which remained within acceptable limits. Conclusions : HPLC analytical method is linear, accurate, precise, robust and specific, being able to separate the main drug from its degradation products. It may find application for the routine analysis of the related substances of both Telmisartan and Hydrochlorthiazide in this combination tablets.

  20. A reverse phased high-pressure liquid chromatographic method for the estimation of a poisonous matter in Strychnos nux-vomica

    Directory of Open Access Journals (Sweden)

    Achu Hashim

    2015-01-01

    Full Text Available Seeds of Strychnos nux-vomica were subjected to preliminary phytochemical tests and its presence was confirmed by thin layer chromatography (TLC method. The TLC profile of the methanolic extract of seeds of S. nux-vomica was developed using the solvent system toluene:chloroform:methanol in the ratio 8:2:1. The plate was observed in visible light after spraying with Dragendorff′s reagent (specific method. High-performance liquid chromatography (HPLC profile of the methanolic extracts of S. nux-vomica was developed, and the amount of strychnine seems to be 0.36% (w/w in the seeds. The TLC and HPLC profiles developed are very valuable for the identification of the original drug from their adulterants. The TLC profile identifies the presence of strychnine in the plant material. The quantification method for the strychnine in the seeds can be used for the quality standardization of the raw drug because the strychnine is reported to have some toxicity.

  1. An Ultra-High Performance Liquid Chromatographic-Tandem Mass Spectrometric Method for the Determination of Sinomenine in Human Plasma after Transdermal Delivery of the Zhengqing Fengtongning Injection

    Directory of Open Access Journals (Sweden)

    Tingbo Chen

    2015-04-01

    Full Text Available A sensitive, precise and selective ultra-high performance liquid chromatography method coupled with triple-quadrupole mass spectrometry was developed and validated for the determination of trace amounts of sinomenine (ng/mL in minute volumes of human plasma. Fifty microliter plasma samples were precipitated using methanol to extract sinomenine. Separation was carried out on a C18 column with a water and acetonitrile mobile phase gradient with formic acid as an additive. The mass spectrometry data were obtained in the positive ion mode, and the transition of multiple reactions was monitored at m/z 330.2→181.0 for sinomenine quantification. The working assay range for sinomenine was linear from 0.1173 to 15.02 ng/mL with the lower limit of quantification of 0.1173 ng/mL. The precision and accuracy of the method was less than 15% in intra-day and inter-day experiments with a matrix effect of less than 6.5%. After validation, the quantitative method was applied to analyze sinomenine levels in human plasma after transdermal delivery of the Zhengqing Fengtongning Injection. The results showed that some samples contained sinomenine within the concentration range 0.4131–4.407 ng/mL.

  2. Development and validation of a robust high-performance liquid chromatographic method for the analysis of monacolins in red yeast rice.

    Science.gov (United States)

    Theunis, Mart; Naessens, Tania; Verhoeven, Veronique; Hermans, Nina; Apers, Sandra

    2017-11-01

    A robust analytical method, using reversed phase high-performance liquid chromatography with diode array detection, was developed and validated for the quantification of monacolins in red yeast rice bulk products. Tests on the composition of the extraction solvent, extraction time and the number of repetitions of extraction were evaluated with the aim of complete extraction of the monacolins and minimal transitions between the monacolins during analysis. Monacolin K (acid form), monacolin K (lactone form) and minor monacolin peaks were separated on a C18 column (250×4.6mm, 5µm) using acetonitrile/0.1% trifluoroacetic acid as the mobile phase. For the calibration curve of monacolin K (lactone form), a linear correlation in the range 6-119µg/mL was found. The precision of the method for time and concentration gave a relative standard deviation of less than 5%, which was deemed acceptable. The recovery of the method was 98.75%. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Single-Laboratory Validation of a High-Performance Liquid Chromatographic-Diode Array Detector-Fluorescence Detector/Mass Spectrometric Method for Simultaneous Determination of Water-Soluble Vitamins in Multivitamin Dietary Tablets

    Science.gov (United States)

    Chen, Pei; Atkinson, Renata; Wolf, Wayne R.

    2014-01-01

    The purpose of this study was to develop a single-laboratory validated (SLV) method using high-performance liquid chromatography with different detectors [diode array detector (DAD); fluorescence detector (FLD); and mass spectrometry (MS)] for determination of 7 B-complex vitamins (B1-thiamin, B2-riboflavin, B3-nicotinamide, B6-pyridoxine, B9-folic acid, pantothenic acid, and biotin) and vitamin C in multivitamin/multimineral dietary supplements. The method involves the use of a reversed-phase octadecylsilyl column (4 µm, 250 × 2.0 mm id) and a gradient mobile phase profile. Gradient elution was performed at a flow rate of 0.25 mL/min. After a 5 min isocratic elution at 100% A (0.1% formic acid in water), a linear gradient to 50% A and 50% B (0.1% formic acid in acetonitrile) at 15 min was employed. Detection was performed with a DAD as well as either an FLD or a triple-quadrupole MS detector in the multiple reaction monitoring mode. SLV was performed using Standard Reference Material (SRM) 3280 Multivitamin/Multimineral Tablets, being developed by the National Institute of Standards and Technology, with support by the Office of Dietary Supplements of the National Institutes of Health. Phosphate buffer (10 mM, pH 2.0) extracts of the NIST SRM 3280 were analyzed by the liquid chromatographic (LC)-DAD-FLD/MS method. Following extraction, the method does not require any sample cleanup/preconcentration steps except centrifugation and filtration. PMID:19485230

  4. Analysis of volatile compounds responsible for kiwifruit aroma by desiccated headspace gas chromatography-mass spectrometry.

    Science.gov (United States)

    Zhang, Chun-Yun; Zhang, Qiong; Zhong, Cai-Hong; Guo, Ming-Quan

    2016-04-01

    A new method for desiccated headspace (DHS) sampling of aqueous sample to GC-MS for the analysis of volatile compounds responsible for kiwifruit aroma in different kiwifruit cultivars has been developed based on the complete hydrate formation between the sample solvent (water) with anhydrous salt (calcium chloride) at an elevated temperature (above the boiling point of the aqueous sample) in a non-contact format, which overcame the water-effect challenge to directly introduce aqueous sample into GC-MS analysis. By means of DHS, the volatile compounds in three different kiwifruit cultivars were analyzed and compared under the optimized operating conditions, mainly time and temperature for headspace equilibration, column temperature program for GC-MS measurement. As a result, 20 peaks of volatile compounds responsible for kiwifruit aroma were detected and remarkable differences were found in the relative contents of three major volatile compounds among the three different kiwifruit cultivars, i.e., acetaldehyde, ethanol and furfural. The DHS sampling technique used in the present method can make the GC-MS analysis of volatile compounds in the aqueous sample within complex matrix possible without contaminating the GC-MS instrument. In terms of the analysis of volatile compounds in kiwifruit, the present method enabled a direct measurement on the filtrate of the aqueous kiwifruit pulp, without intermediate trap phase for the extraction of analytes, which will be more reliable and simpler as compared with any other headspace method in use. Thus, DHS coupled with GC-MS will be a new valuable tool available for the kiwifruit related research and organoleptic quality control. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Development of a High-Performance Liquid Chromatographic Method for Asiaticoside Quantification in Different Skin Layers after Topical Application of a Centella asiatica Extract.

    Science.gov (United States)

    da Rocha, Priscila Bianca Rodrigues; Souza, Bruno Dos Santos; Andrade, Lígia Marquez; Marreto, Ricardo Neves; Lima, Eliana Martins; Taveira, Stephânia Fleury

    2017-12-01

    The topical application of Centella asiatica extract has been commonly used for many different purposes but especially for cosmetic use in the treatment of gynoid lipodystrophy. Asiaticoside, the most active component in this extract, is responsible for its therapeutic activities. However, little is known to date about asiaticoside skin penetration. Thus, an analytical method for asiaticoside quantification in different skin layers after the topical application of C. asiatica extract was developed and skin permeation studies were performed with the plant extract to apply the analytical method developed. An extraction procedure to recover asiaticoside from the biological matrix was also developed. Asiaticoside was assayed by HPLC/UV (high-performance liquid chromatography-ultraviolet detection) using a gradient of ACN (acetonitrile) and 0.2% phosphoric acid (flow rate of 1.0 mL/min). The analytical procedure was validated according to U. S. Food and Drug Administration guidelines. Selectivity was shown, as endogenous skin components did not interfere with the asiaticoside peak. Analytical curve was linear (3 to 60 µg/mL) and the lower limit of quantification was determined (3 µg/mL). Asiaticoside recoveries from skin samples were 95.1% and 66.7% for the stratum corneum and remaining skin, respectively. After 48 h of in vitro permeation studies, a substantial amount of asiaticoside was quantified in the skin layers. The presence of asiaticoside was also detected in the receptor solution of Franz diffusion cells after 48 h (5.81 ± 1.00 µg/mL). The method was reliable and reproducible for asiaticoside quantification in skin samples, thereby making it possible to determine the cutaneous penetration profile of this drug in permeation studies. Georg Thieme Verlag KG Stuttgart · New York.

  6. Liquid Chromatographic Determination of Alternaria Toxins in Carrots

    NARCIS (Netherlands)

    Solfrizzo, M.; Girolamo, De A.; Vitti, C.; Bulk, van den R.W.

    2004-01-01

    A liquid chromatographic (LC) method was developed for the determination of Alternaria radicina and A. alternata toxins in carrots. Toxins were extracted from carrot with an acidified mixture of water¿methanol¿acetonitrile. The filtered extract was divided in 2 parts that were purified by

  7. Liquid chromatographic-tandem mass spectrometric assay for ...

    African Journals Online (AJOL)

    the range -1.85 to 1.22 %) and precision (0.71 - 5.12 %). The method was also validated in terms of .... Technologies,. CA,. USA). Analytes chromatographic elution was accomplished utilizing a mobile phase containing solvents A;. Acetonitrile (ACN) and B; 0.01 M ammonium formate buffer (pH~4.1) pumped binarily at 0.3.

  8. Method to predict gas chromatographic response factors for the trace-level analysis of volatile organic compounds based on the effective carbon number concept.

    Science.gov (United States)

    Szulejko, Jan E; Kim, Yong-Hyun; Kim, Ki-Hyun

    2013-10-01

    A procedure has been developed to estimate GC-MS response factors based on the theory of effective carbon number defined as the sum of the carbon number and carbon number equivalent for each selected molecular descriptor (multiplied by its number of occurrences) in each compound's molecular structure. As a means to validate the effective carbon number procedure for GC-MS analysis, a test suite of 19 volatile organic compounds was analyzed by the sorbent-tube thermal desorption method. In the effective carbon number procedure, the carbon number equivalent for each descriptor was determined to yield the optimal linear plots between response factor versus the effective carbon number with the maximum R(2) (>0.975) and the minimum mean absolute error (analysis is validated as a potent approach to estimate response factor values for most compounds amenable to the sorbent-tube thermal desorption GC-MS method. Overall, it is concluded that the application of response factor versus effective carbon number relationship can produce fairly reliable prediction with reduced errors relative to other comparable procedures such as the response factor versus the carbon number approach. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Rapid method for simultaneous determination of nitrite and nitrate in water samples using short-column ion-pair chromatographic separation, photochemical reaction, and chemiluminescence detection.

    Science.gov (United States)

    Kodamatani, Hitoshi; Yamazaki, Shigeo; Saito, Keiitsu; Komatsu, Yu; Tomiyasu, Takashi

    2011-01-01

    A rapid method has been developed for the simultaneous determination of nitrite and nitrate. The separation of nitrite and nitrate was achieved using an octadecylsilane (ODS) short column (5 µm, 20 × 4.6 mm) with 10 mM of borate buffer-methanol (99.5:0.5, v/v; pH 10.0), containing 5 mM of lauryltrimethylammonium chloride and 50 mM of NaBr. These ions were detected by luminol chemiluminescence following online UV irradiation. The calibration curves of nitrite and nitrate were linear in the range of 1.0 × 10(-7) to 2.0 × 10(-5) M and 1.0 × 10(-6) to 2.0 × 10(-4) M, respectively. The detection limits for nitrite and nitrate were 0.05 and 0.4 µM, respectively (with a signal-to-noise ratio of 3). The precisions of peak heights for 7 identical injections of a standard mixture of 0.50 µM of nitrite and 5.0 µM of nitrate were 2.7 and 2.1%, respectively. Analysis time per sample was less than 2 min, and system pressure was low (2.1 MPa). The proposed method was successfully applied to water samples from various sources.

  10. Determination of several N-methyl-D-aspartate receptor blockers in plasma and brain by a selective high-performance liquid chromatographic method with column switching.

    Science.gov (United States)

    Wyss, R; Bucheli, F; Philipp, W

    1998-02-27

    A general procedure is presented for the determination of several N-methyl-D-aspartate (NMDA) receptor open-channel and subtype-selective blockers, which have been evaluated and developed as neuroprotective drugs for the treatment of brain stroke and trauma. The method involves deproteination of plasma with ethanol, or homogenization of brain samples in ethanol, dilution of the supernatant with ammonium acetate and direct injection into an HPLC column-switching system. Although the investigated NMDA receptor blockers are all tertiary amines, they have quite different structures. However, they are all concentrated on the first column (Purospher RP-18, 125 x 4 mm), whereas polar interfering compounds are washed out with 1% ammonium acetate-acetic acid-acetonitrile (100:1:5, v/v/v). Due to the special selectivity of the Purospher RP-18 material, the analytes and the internal standard are then selectively eluted with 25% acetonitrile (without any buffer in the mobile phase) and transferred to the analytical column (Superspher 60 RP-select B, 250 x 4 mm), where they are separated by gradient elution and detected by UV or fluorescence detection. The low degree of interference allowed the development of sensitive methods with quantification limits of 5 ng/ml for animal plasma (0.4 ml used), 0.5 ng/ml for human plasma (1 ml used) and 50 ng/g for brain tissue (200 mg used).

  11. A rapid method for the chromatographic analysis of volatile organic compounds in exhaled breath of tobacco cigarette and electronic cigarette smokers.

    Science.gov (United States)

    Marco, Esther; Grimalt, Joan O

    2015-09-04

    A method for the rapid analysis of volatile organic compounds (VOCs) in smoke from tobacco and electronic cigarettes and in exhaled breath of users of these smoking systems has been developed. Both disposable and rechargeable e-cigarettes were considered. Smoke or breath were collected in Bio-VOCs. VOCs were then desorbed in Tenax cartridges which were subsequently analyzed by thermal desorption coupled to gas chromatography-mass spectrometry. The method provides consistent results when comparing the VOC compositions from cigarette smoke and the equivalent exhaled breath of the smokers. The differences in composition of these two sample types are useful to ascertain which compounds are retained in the respiratory system after tobacco cigarette or e-cigarette smoking. Strong differences were observed in the VOC composition of tobacco cigarette smoke and exhaled breath when comparing with those of e-cigarette smoking. The former involved transfers of a much larger burden of organic compounds into smokers, including benzene, toluene, naphthalene and other pollutants of general concern. e-Cigarettes led to strong absorptions of propylene glycol and glycerin in the users of these systems. Tobacco cigarettes were also those showing highest concentration differences between nicotine concentrations in smoke and exhaled breath. The results from disposable e-cigarettes were very similar to those from rechargeable e-cigarettes. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Development of new efficient method for isolation of phenolics from sea algae prior to their rapid resolution liquid chromatographic-tandem mass spectrometric determination.

    Science.gov (United States)

    Klejdus, Bořivoj; Plaza, Merichel; Šnóblová, Marie; Lojková, Lea

    2017-02-20

    The extraction of phenolic compounds from 4 different sea algae samples, three brown algae (Cystoseira abies-marina, C. abies-marina grinded under cryogenic conditions with liquid nitrogen, Undaria pinnatifida and Sargassum muticum) and one red algae (Chondrus crispus) via solid phase extraction using micro-elution solid-phase extraction (μ-SPE) plate method was studied. Prior to μ-SPE, 50mg of algae with 80% methanol mixture was extracted in hyphenated series by various extraction techniques, such as pressurized liquid extraction and Ika Ultra-Turrax® Tube Drive, in combination with ultrasound assisted extraction. The μ-SPE plate technique reduced the time of sample pre-treatment thanks to higher sensitivity and pre-concentration effect. Selected groups of benzoic acid derivatives (p-hydroxybenzoic, protocatechuic, gallic, vanillic, and syringic acids), hydroxybenzaldehydes (4-hydroxybenzaldehyde, and 3,4-dihydroxybenzaldehyde), and cinnamic acid derivatives (p-coumaric, caffeic, ferulic, sinapic, and chlorogenic acids) were determined using rapid resolution liquid chromatography coupled to mass spectrometry detection with negative ion electrospray ionization (RRLC-ESI-MS) using multiple reactions monitoring. LOQs of measured samples varied in the range 0.23-1.68ng/mL and LODs in the range 0.07-0.52ng/mL. The applied method allowed a simultaneous determination of phenolics (i.e. free, esters soluble in methanol, glycosides, and esters insoluble in methanol) in less than 5min (including alkaline or acidic hydrolysis of raw extracts) from sea algae extracts. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Analytical strategies based on multiple headspace extraction for the quantitative analysis of aroma components in mushrooms.

    Science.gov (United States)

    San Román, I; Alonso, M L; Bartolomé, L; Alonso, R M; Fañanás, R

    2014-06-01

    Headspace (HS) and headspace solid phase microextraction (HS-SPME) analysis by gas chromatography-mass spectrometry (GC/MS) have been found to be suitable methods for the analysis of volatile organic compounds. The objectives of this paper are to study the possibilities of multiple headspace extraction (MHE) for the quantitative determination of volatile compounds in mushroom samples and to compare the results obtained using three different sample treatment techniques. For this purpose, HS with two different injection techniques (pressure-loop system and gas-tight syringe autosampling system) and HS-SPME have been studied. Three processes were optimized for the analysis of 20 volatile compounds by experimental design technique based on Central Composite Design (CCD) and Full Factorial Design depending on the used methodology. Once the designs were finished, a trade off among optimum conditions for each compound analyzed was reached. At optimum conditions, appropriate extraction time and sample amount for the three techniques used were established. Finally, the methods were validated in terms of linearity, detection and quantitation limits and repeatability. The most suitable method was then applied to the quantitative analysis of seven mushroom samples. A detailed comparison of the analytical performance characteristics of HS and HS-SPME as sample treatment techniques for final GC/MS determination is given. In addition, MHE has been proved to be an adequate technique to avoid matrix effects in complex samples quantitation. Its applicability to the determination of volatile mushroom components, along with its limitations, is discussed in this work. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Vacuum-assisted headspace solid-phase microextraction: A tutorial review.

    Science.gov (United States)

    Psillakis, Elefteria

    2017-09-15

    Headspace solid-phase microextraction (HSSPME) sampling under vacuum conditions is a new and effective approach to accelerate the extraction kinetics of analytes with a low affinity for the headspace. Vacuum-assisted HSSPME (Vac-HSSPME) evolved from this approach and the resulting methods were always found to yield high extraction efficiencies and very good sensitivities within short sampling times and at mild temperatures. Vac-HSSPME preserves the simplicity of regular HSSPME and the only extra step required is that of air-evacuating the sample container before or after introducing the sample. Moreover, fast implementation of the technique is possible when using the latest, simplified and easy to construct sample container that can hold constant low-pressure conditions for extended sampling times. The main objective of the current tutorial is to provide a general strategy that can be applied towards the development of new Vac-HSSPME methods. The most important outcomes of past theoretical investigations are highlighted and a simple criterion for predicting the effect of vacuum on HSSPME sampling of water or water-containing samples is outlined. This theoretical discussion is then used as a background to elucidate the combined effects of low sampling pressure and several other experimental parameters on HSSPME sampling. Specific implications unique to Vac-HSSPME are also discussed, providing practical tips and a troubleshooting guide to new users. The great benefits of adopting the Vac-HSSPME approach are further demonstrated by reviewing all past applications reporting the quantitative and/or qualitative determination of compounds with a low tendency to escape to the headspace in a variety of samples. Vacuum is a new experimental parameter to control and exploit during HSSPME method optimization. The potential applications of Vac-HSSPME in areas like food, environmental and biological analysis are numerous and still remain to be explored. Copyright © 2017

  15. Magnetic headspace adsorptive extraction of chlorobenzenes prior to thermal desorption gas chromatography-mass spectrometry.

    Science.gov (United States)

    Vidal, Lorena; Ahmadi, Mazaher; Fernández, Elena; Madrakian, Tayyebeh; Canals, Antonio

    2017-06-08

    This study presents a new, user-friendly, cost-effective and portable headspace solid-phase extraction technique based on graphene oxide decorated with iron oxide magnetic nanoparticles as sorbent, located on one end of a small neodymium magnet. Hence, the new headspace solid-phase extraction technique has been called Magnetic Headspace Adsorptive Extraction (Mag-HSAE). In order to assess Mag-HSAE technique applicability to model analytes, some chlorobenzenes were extracted from water samples prior to gas chromatography-mass spectrometry determination. A multivariate approach was employed to optimize the experimental parameters affecting Mag-HSAE. The method was evaluated under optimized extraction conditions (i.e., sample volume, 20 mL; extraction time, 30 min; sorbent amount, 10 mg; stirring speed, 1500 rpm, and ionic strength, non-significant), obtaining a linear response from 0.5 to 100 ng L-1 for 1,3-DCB, 1,4-DCB, 1,2-DCB, 1,3,5-TCB, 1,2,4-TCB and 1,2,3-TCB; from 0.5 to 75 ng L-1 for 1,2,4,5-TeCB, and PeCB; and from 1 to 75 ng L-1 for 1,2,3,4-TeCB. The repeatability of the proposed method was evaluated at 10 ng L-1 and 50 ng L-1 spiking levels, and coefficients of variation ranged between 1.5 and 9.5% (n = 5). Limits of detection values were found between 93 and 301 pg L-1. Finally, tap, mineral and effluent water were selected as real water samples to assess method applicability. Relative recoveries varied between 86 and 110% showing negligible matrix effects. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. A new method for direct total OH reactivity measurements using a fast Gas Chromatographic Photo-Ionization Detector (GC-PID)

    Science.gov (United States)

    Nölscher, A. C.; Sinha, V.; Bockisch, S.; Klüpfel, T.; Williams, J.

    2012-04-01

    The primary and most important oxidant in the troposphere is the hydroxyl radical (OH). Currently the atmospheric sinks of OH are poorly constrained. One way to characterize the overall sink term of OH is to measure directly the ambient loss rate of OH, the total OH reactivity. The first direct measurements of total OH reactivity were performed using laser induced fluorescence (LIF) [1], [2]. Recently a new method for determining OH reactivity was developed called the comparative reactivity method (CRM) [3]. The measurement principle is based on a competitive reaction between a reactive molecule not normally present in air with OH, and atmospheric OH reactive molecules with OH. The reactive molecule (X), is passed through a Teflon coated glass reactor and its concentration is monitored with a suitable detector. OH radicals are then introduced into the reactor at a constant rate to react with X, first in the presence of zero air and then in the presence of ambient air containing OH reactive species. Comparing the amount of X exiting the reactor with and without the competing ambient air molecules directly provides the atmospheric total OH reactivity. In the first version of this set up, molecule X is pyrrole (C5H4N) and the detector used is a proton transfer reaction mass spectrometer (PTR-MS). In comparison to the original LIF based system, the PTR-MS has the advantage of being smaller, less expensive, and commercially available. However, using the PTR-MS for total OH reactivity measurements prevents it from probing the broad variety of volatile organic compounds in ambient air. Moreover, even smaller, less expensive and more portable detectors are available. This work examines the potential for a GC-PID in order to make the total OH reactivity measurement accessible to more practitioners. This study presents measurements of total OH reactivity with a custom built GC-PID (VOC-Analyzer from IUT-Berlin, now ENIT (Environics-IUT GmbH))[4]. The GC-PID is small (260

  17. High-performance liquid chromatographic method to evaluate the hydrogen atom transfer during reaction between 1,1-diphenyl-2-picryl-hydrazyl radical and antioxidants

    Energy Technology Data Exchange (ETDEWEB)

    Boudier, Ariane; Tournebize, Juliana [CITHEFOR - EA 3452, Faculte de Pharmacie, Nancy-Universite, 5 Rue Albert Lebrun, BP 80403, 54001 Nancy Cedex (France); Bartosz, Grzegorz [Department of Molecular Biophysics, University of Lodz, Lodz (Poland); El Hani, Safae; Bengueddour, Rachid [Laboratoire de Nutrition et Sante, Biology Department, Faculty of Sciences, Ibn Tofail University, Kenitra (Morocco); Sapin-Minet, Anne [CITHEFOR - EA 3452, Faculte de Pharmacie, Nancy-Universite, 5 Rue Albert Lebrun, BP 80403, 54001 Nancy Cedex (France); Leroy, Pierre, E-mail: pierre.leroy@pharma.uhp-nancy.fr [CITHEFOR - EA 3452, Faculte de Pharmacie, Nancy-Universite, 5 Rue Albert Lebrun, BP 80403, 54001 Nancy Cedex (France)

    2012-01-20

    Highlights: Black-Right-Pointing-Pointer Both 1,1-diphenyl-2-picrylhydrazyl radical and its product measurement by HPLC. Black-Right-Pointing-Pointer Lowest limit of detection by monitoring 1,1-diphenyl-2-picryl-hydrazine. Black-Right-Pointing-Pointer Adsorption problem of the radical on HPLC parts have been pointed out. - Abstract: 1,1-Diphenyl-2-picrylhydrazyl (DPPH{center_dot}) is a stable nitrogen centred radical widely used to evaluate direct radical scavenging properties of various synthetic or natural antioxidants (AOs). The bleaching rate of DPPH{center_dot} absorbance at 515 nm is usually monitored for this purpose. In order to avoid the interference of complex coloured natural products used as antioxidant supplements or cosmetics, HPLC systems have been reported as alternative techniques to spectrophotometry. They also rely upon measurement of DPPH{center_dot} quenching rate and none of them permits to identify and measure 1,1-diphenyl-2-picryl-hydrazine (DPPH-H), the reduced product of DPPH{center_dot} resulting from hydrogen atom transfer (HAT), which is the main mechanism of the reaction between DPPH{center_dot} and AOs. We presently report an HPLC method devoted to the simultaneous measurement of DPPH{center_dot} and DPPH-H. Both were fully separated on a C18 column eluted with acetonitrile-10 mM ammonium citrate buffer pH 6.8 (70:30, v/v) and detected at 330 nm. Adsorption process of DPPH{center_dot} onto materials of the HPLC system was pointed out. Consequently, the linearity range observed for DPPH{center_dot} was restricted, thus a much lower limit of detection was obtained for DPPH-H than for DPPH{center_dot} using standards (0.02 and 14 {mu}M, respectively). The method was applied to three commonly used AOs, i.e. Trolox{sup Registered-Sign }, ascorbic acid and GSH, and compared with spectrophotometry. Further application to complex matrices (cell culture media, vegetal extracts) and nanomaterials demonstrated (i) its usefulness because of

  18. Polyaniline-nylon-6 electrospun nanofibers for headspace adsorptive microextraction.

    Science.gov (United States)

    Bagheri, Habib; Aghakhani, Ali

    2012-02-03

    A headspace adsorptive microextraction technique was developed using a novel polyaniline-nylon-6 (PANI-N6) nanofiber sheet, fabricated by electrospinning. The homogeneity and the porosity of the prepared PANI-N6 sheet were studied using the scanning electron microscopy (SEM) and nanofibers diameters were found to be around 200 nm. The novel nanofiber sheet was examined as an extracting medium to isolate some selected chlorobenzenes (CBs), as model compounds, from aquatic media. The extracted analytes were desorbed using μL-amounts of solvent and eventually an aliquot of extractant was injected into gas chromatography-mass spectrometry (GC-MS). Various parameters affecting the extraction and desorption processes were optimized. The developed method proved to be convenient and offers sufficient sensitivity and a good reproducibility. Limits of detection achieved for CBs with the developed analytical procedure ranged from 19 to 33 ng L(-1), while limits of quantification were from 50 to 60 ng L(-1). The relative standard deviations (RSD) at a concentration level of 0.1 ng mL(-1) and 1 ng mL(-1) were in the range of 8-14% and 5-11% (n=3), respectively. The calibration curves of analytes were investigated in the range of 50-1000 ng L(-1) and R(2) between 0.9739 and 0.9932 were obtained. The developed method was successfully applied to the extraction of selected CBs from tap and river water samples. The relative recovery (RR) percentage obtained for the spiked real water samples at 0.1 ng mL(-1) and 1 ng mL(-1) level were 93-103% and 95-104%, respectively. The whole procedure showed to be conveniently applicable and quite easy to handle. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. Dynamic headspace generation and quantitation of triacetone triperoxide vapor.

    Science.gov (United States)

    Giordano, Braden C; Lubrano, Adam L; Field, Christopher R; Collins, Greg E

    2014-02-28

    Two methods for quantitation of triacetone triperoxide (TATP) vapor using a programmable temperature vaporization (PTV) inlet coupled to a gas chromatography/mass spectrometer (GC/MS) have been demonstrated. The dynamic headspace of bulk TATP was mixed with clean humid air to produce a TATP vapor stream. Sampling via a heated transfer line to a PTV inlet with a Tenax-TA™ filled liner allowed for direct injection of the vapor stream to a GC/MS for vapor quantitation. TATP was extracted from the vapor stream and subsequently desorbed from the PTV liner for splitless injection on the GC column. Calibration curves were prepared using solution standards with a standard split/splitless GC inlet for quantitation of the TATP vapor. Alternatively, vapor was sampled onto a Tenax-TA™ sample tube and placed into a thermal desorption system. In this instance, vapor was desorbed from the tube and subsequently trapped on a liquid nitrogen cooled PTV inlet. Calibration curves for this method were prepared from direct liquid injection of standards onto samples tube with the caveat that a vacuum is applied to the tube during deposition to ensure that the volatile TATP penetrates into the tube. Vapor concentration measurements, as determined by either GC/MS analysis or mass gravimetry of the bulk TATP, were statistically indistinguishable. Different approaches to broaden the TATP vapor dynamic range, including diluent air flow, sample chamber temperature, sample vial orifice size, and sample size are discussed. Vapor concentrations between 50 and 5400ngL(-1) are reported, with stable vapor generation observed for as long as 60 consecutive hours. Published by Elsevier B.V.

  20. Systematic interpolation method predicts protein chromatographic elution with salt gradients, pH gradients and combined salt/pH gradients.

    Science.gov (United States)

    Creasy, Arch; Barker, Gregory; Carta, Giorgio

    2017-03-01

    A methodology is presented to predict protein elution behavior from an ion exchange column using both individual or combined pH and salt gradients based on high-throughput batch isotherm data. The buffer compositions are first optimized to generate linear pH gradients from pH 5.5 to 7 with defined concentrations of sodium chloride. Next, high-throughput batch isotherm data are collected for a monoclonal antibody on the cation exchange resin POROS XS over a range of protein concentrations, salt concentrations, and solution pH. Finally, a previously developed empirical interpolation (EI) method is extended to describe protein binding as a function of the protein and salt concentration and solution pH without using an explicit isotherm model. The interpolated isotherm data are then used with a lumped kinetic model to predict the protein elution behavior. Experimental results obtained for laboratory scale columns show excellent agreement with the predicted elution curves for both individual or combined pH and salt gradients at protein loads up to 45 mg/mL of column. Numerical studies show that the model predictions are robust as long as the isotherm data cover the range of mobile phase compositions where the protein actually elutes from the column. Copyright © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Determination of two mebeverine metabolites, mebeverine alcohol and desmethylmebeverine alcohol, in human plasma by a dual stable isotope-based gas chromatographic-mass spectrometric method.

    Science.gov (United States)

    Tulich, L J; Randall, J L; Kelm, G R; Wehmeyer, K R

    1996-07-12

    A dual stable isotope-based GC-MS method was developed for the simultaneous determination of two metabolites of mebeverine, mebeverine alcohol and desmethylmebeverine alcohol, in human plasma. Plasma samples were treated with beta-glucuronidase to cleave the glucuronide conjugates of both compounds prior to analysis. The treated plasma was prepared for analysis by solid-phase extraction using octadecylsilane cartridges. The isolated metabolites were derivatized and analyzed by GC-MS using selected-ion monitoring. Plots of peak-area ratio were linear with metabolite concentration from 2 to 200 ng/ml and the limit of detection for both metabolites was 0.5 ng/ml. The GC-MS methodology was applied to the analysis of plasma from human subjects following peroral administration of mebeverine. Pharmacokinetic parameters for both metabolites were determined and suggest that relative systemic mebeverine exposure may potentially be assessed using metabolite kinetics, if the latter subsequently are demonstrated to be linear with mebeverine dose.

  2. Coal liquefaction process streams characterization and evaluation: Application of liquid chromatographic separation methods to THF-soluble portions of integrated two-stage coal liquefaction resids

    Energy Technology Data Exchange (ETDEWEB)

    Green, J.B.; Pearson, C.D.; Young, L.L.; Green, J.A. (National Inst. for Petroleum and Energy Research, Bartlesville, OK (United States))

    1992-05-01

    This study demonstrated the feasibility of using non-aqueous ion exchange liquid chromatography (NIELC) for the examination of the tetrahydrofuran (THF)-soluble distillation resids and THF-soluble whole oils derived from direct coal liquefaction. The technique can be used to separate the material into a number of acid, base, and neutral fractions. Each of the fractions obtained by NIELC was analyzed and then further fractionated by high-performance liquid chromatography (HPLC). The separation and analysis schemes are given in the accompanying report. With this approach, differences can be distinguished among samples obtained from different process streams in the liquefaction plant and among samples obtained at the same sampling location, but produced from different feed coals. HPLC was directly applied to one THF-soluble whole process oil without the NIELC preparation, with limited success. The direct HPLC technique used was directed toward the elution of the acid species into defined classes. The non-retained neutral and basic components of the oil were not analyzable by the direct HPLC method because of solubility limitations. Sample solubility is a major concern in the application of these techniques.

  3. Multiple chromatographic fingerprinting and its application to the quality control of herbal medicines

    Energy Technology Data Exchange (ETDEWEB)

    Fan Xiaohui [Pharmaceutical Informatics Institute, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310027 (China); Cheng Yiyu [Pharmaceutical Informatics Institute, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310027 (China)]. E-mail: chengyy@zju.edu.cn; Ye Zhengliang [Pharmaceutical Informatics Institute, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310027 (China); Lin Ruichao [National Institute for the Control of Pharmaceutical and Biological Products, Beijing 100050 (China); Qian Zhongzhi [Committee of Chinese Pharmacopoeia, Beijing 100061 (China)

    2006-01-12

    Recently, chromatographic fingerprinting has become one of the most powerful approaches to quality control of herbal medicines. However, the performance of reported chromatographic fingerprinting constructed by single chromatogram sometimes turns out to be inadequate for complex herbal medicines, such as multi-herb botanical drug products. In this study, multiple chromatographic fingerprinting, which consists of more than one chromatographic fingerprint and represents the whole characteristics of chemical constitutions of the complex medicine, is proposed as a potential strategy in this complicated case. As a typical example, a binary chromatographic fingerprinting of 'Danshen Dropping Pill' (DSDP), the best-sold traditional Chinese medicine in China, was developed. First, two HPLC fingerprints that, respectively, represent chemical characteristics of depsides and saponins of DSDP were developed, which were used to construct binary chromatographic fingerprints of DSDP. Moreover, the authentication and validation of the binary fingerprints were performed. Then, a data-level information fusion method was employed to capture the chemical information encoded in two chromatographic fingerprints. Based on the fusion results, the lot-to-lot consistency and frauds can be determined either using similarity measure or by chemometrics approach. The application of binary chromatographic fingerprinting to consistency assessment and frauds detection of DSDP clearly demonstrated that the proposed method was a powerful approach to quality control of complex herbal medicines.

  4. New reversed phase-high performance liquid chromatographic method for selective separation of yttrium from all rare earth elements employing nitrilotriacetate complexes in anion exchange mode.

    Science.gov (United States)

    Dybczyński, Rajmund S; Kulisa, Krzysztof; Pyszynska, Marta; Bojanowska-Czajka, Anna

    2015-03-20

    Separation of Y from other rare earth elements (REE) is difficult because of similarity of its ionic radius to ionic radii of Tb, Dy and Ho. In the new RP-HPLC system with C18 column, tetra-n-butyl ammonium hydroxide (TBAOH) as an ion interaction reagent (IIR), nitrilotriacetic acid (NTA) as a complexing agent at pH=2.8-3.5, and post column derivatization with Arsenazo III, yttrium is eluted in the region of light REE, between Nd and Sm and is base line separated from Nd and Sm and even from promethium. Simple model employing literature data on complex formation of REE with NTA and based on anion exchange mechanism was developed to foresee the order of elution of individual REE. The model correctly predicted that lanthanides up to Tb will be eluted in the order of increasing Atomic Number (At.No.) but all heavier REE will show smaller retention factors than Tb. Concurrent UV/VIS detection at 658nm and the use of radioactive tracers together with γ-ray spectrometric measurements made possible to establish an unique elution order of elution of REE: La, Ce, Pr, Nd, Pm, Y, Sm, Er, Ho, Tm, Yb, Eu, Lu, Dy+Gd, Tb, Sc. The real place of Y however, in this elution series differs from that predicted by the model (Y between Sm and Eu). The method described in this work enables selective separation of Y from La, Ce, Pr, Nd, Pm, Sm and all heavier REE treated as a group. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Using Single Drop Microextraction for Headspace Analysis with Gas Chromatography

    Science.gov (United States)

    Riccio, Daniel; Wood, Derrick C.; Miller, James M.

    2008-01-01

    Headspace (HS) gas chromatography (GC) is commonly used to analyze samples that contain non-volatiles. In 1996, a new sampling technique called single drop microextraction, SDME, was introduced, and in 2001 it was applied to HS analysis. It is a simple technique that uses equipment normally found in the undergraduate laboratory, making it ideal…

  6. Quality control of raw cows' milk by headspace analysis

    NARCIS (Netherlands)

    Hettinga, K.A.; Valenberg, van H.J.F.; Hooijdonk, van A.C.M.

    2008-01-01

    This study investigated whether headspace analysis of volatile components can be used for monitoring the quality of raw cows¿ milk. The detection of different quality defects caused by cows¿ feed, microbiological and chemical contamination, as well as enzymatic deterioration was studied. Fresh raw

  7. Optimization of headspace solid-phase microextraction technique for extraction of volatile smokeless powder compounds in forensic applications.

    Science.gov (United States)

    Chang, Kah Haw; Yew, Chong Hooi; Abdullah, Ahmad Fahmi Lim

    2014-07-01

    Smokeless powders are low explosives and are potentially found in cases involving firearms and improvised explosive devices. Apart from inorganic compound analysis, forensic determination of organic components of these materials appears as a promising alternative, especially the chromatographic techniques. This work describes the optimization of a solid-phase microextraction technique using an 85 μm polyacrylate fiber followed by gas chromatography-flame ionization detection for smokeless powder. A multivariate experimental design was performed to optimize extraction-influencing parameters. A 2(4) factorial first-order design revealed that sample temperature and extraction time were the major influencing parameters. Doehlert matrix design has subsequently selected 66°C and 21 min as the compromised conditions for the two predetermined parameters. This extraction technique has successfully detected the headspace compounds of smokeless powders from different ammunition types and allowed for their differentiation. The novel technique allows more rapid sample preparation for chromatographic detection of smokeless powders. © 2014 American Academy of Forensic Sciences.

  8. Development of a validated liquid chromatographic method for quantification of sorafenib tosylate in the presence of stress-induced degradation products and in biological matrix employing analytical quality by design approach.

    Science.gov (United States)

    Sharma, Teenu; Khurana, Rajneet Kaur; Jain, Atul; Katare, O P; Singh, Bhupinder

    2017-12-15

    The current research work envisages an analytical quality by design-enabled development of a simple, rapid, sensitive, specific, robust and cost-effective stability-indicating reversed-phase high-performance liquid chromatographic method for determining stress-induced forced-degradation products of sorafenib tosylate (SFN). An Ishikawa fishbone diagram was constructed to embark upon analytical target profile and critical analytical attributes, i.e. peak area, theoretical plates, retention time and peak tailing. Factor screening using Taguchi orthogonal arrays and quality risk assessment studies carried out using failure mode effect analysis aided the selection of critical method parameters, i.e. mobile phase ratio and flow rate potentially affecting the chosen critical analytical attributes. Systematic optimization using response surface methodology of the chosen critical method parameters was carried out employing a two-factor-three-level-13-run, face-centered cubic design. A method operable design region was earmarked providing optimum method performance using numerical and graphical optimization. The optimum method employed a mobile phase composition consisting of acetonitrile and water (containing orthophosphoric acid, pH 4.1) at 65:35 v/v at a flow rate of 0.8 mL/min with UV detection at 265 nm using a C 18 column. Response surface methodology validation studies confirmed good efficiency and sensitivity of the developed method for analysis of SFN in mobile phase as well as in human plasma matrix. The forced degradation studies were conducted under different recommended stress conditions as per ICH Q1A (R2). Mass spectroscopy studies showed that SFN degrades in strongly acidic, alkaline and oxidative hydrolytic conditions at elevated temperature, while the drug was per se found to be photostable. Oxidative hydrolysis using 30% H 2 O 2 showed maximum degradation with products at retention times of 3.35, 3.65, 4.20 and 5.67 min. The absence of any

  9. Determination of decamethylcyclopentasiloxane in river water and final effluent by headspace gas chromatography/mass spectrometry.

    Science.gov (United States)

    Sparham, Chris; Van Egmond, Roger; O'Connor, Sean; Hastie, Colin; Whelan, Mick; Kanda, Rakesh; Franklin, Oliver

    2008-11-28

    A method is described for the analysis of decamethylcyclopentasiloxane (D(5)) in river water and treated waste water using headspace gas chromatography/mass spectrometry. Internal standard addition to samples and field blanks was carried out in the field to provide both a measure of recovery and to prevent any exposure of samples to laboratory air, which contained background levels of D(5). Measured levels of D(5) were typically in the range River Great Ouse (UK) with slightly higher levels in the River Nene (UK). The measured concentration of D(5) in treated waste water varied between 31 and 400ngL(-1), depending on the type of treatment process employed.

  10. Determination of volatile marker compounds in raw ham using headspace-trap gas chromatography.

    Science.gov (United States)

    Bosse Née Danz, Ramona; Wirth, Melanie; Konstanz, Annette; Becker, Thomas; Weiss, Jochen; Gibis, Monika

    2017-03-15

    A simple, reliable and automated method was developed and optimized for qualification and quantification of aroma-relevant volatile marker compounds of North European raw ham using a headspace (HS)-Trap gas chromatography-mass spectrometry (GC-MS) and GC-flame ionization detector (FID) analysis. A total of 38 volatile compounds were detected with this HS-Trap GC-MS method amongst which the largest groups were ketones (12), alcohols (8), hydrocarbons (7), aldehydes (6) and esters (3). The HS-Trap GC-FID method was optimized for the parameters: thermostatting time and temperature, vial and desorption pressure, number of extraction cycles and salt addition. A validation for 13 volatile marker compounds with limits of detection in ng/g was carried out. The optimized method can serve as alternative to conventional headspace and solid phase micro extraction methods and allows users to determine volatile compounds in raw hams making it of interest to industrial and academic meat scientists. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Magnetic headspace adsorptive extraction of chlorobenzenes prior to thermal desorption gas chromatography-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Vidal, Lorena, E-mail: lorena.vidal@ua.es [Department of Analytical Chemistry, Nutrition and Food Sciences and University Institute of Materials, University of Alicante, P.O. Box 99, E-03080, Alicante (Spain); Ahmadi, Mazaher [Faculty of Chemistry, Bu-Ali Sina University, Hamedan (Iran, Islamic Republic of); Fernández, Elena [Department of Analytical Chemistry, Nutrition and Food Sciences and University Institute of Materials, University of Alicante, P.O. Box 99, E-03080, Alicante (Spain); Madrakian, Tayyebeh [Faculty of Chemistry, Bu-Ali Sina University, Hamedan (Iran, Islamic Republic of); Canals, Antonio, E-mail: a.canals@ua.es [Department of Analytical Chemistry, Nutrition and Food Sciences and University Institute of Materials, University of Alicante, P.O. Box 99, E-03080, Alicante (Spain)

    2017-06-08

    This study presents a new, user-friendly, cost-effective and portable headspace solid-phase extraction technique based on graphene oxide decorated with iron oxide magnetic nanoparticles as sorbent, located on one end of a small neodymium magnet. Hence, the new headspace solid-phase extraction technique has been called Magnetic Headspace Adsorptive Extraction (Mag-HSAE). In order to assess Mag-HSAE technique applicability to model analytes, some chlorobenzenes were extracted from water samples prior to gas chromatography-mass spectrometry determination. A multivariate approach was employed to optimize the experimental parameters affecting Mag-HSAE. The method was evaluated under optimized extraction conditions (i.e., sample volume, 20 mL; extraction time, 30 min; sorbent amount, 10 mg; stirring speed, 1500 rpm, and ionic strength, non-significant), obtaining a linear response from 0.5 to 100 ng L{sup −1} for 1,3-DCB, 1,4-DCB, 1,2-DCB, 1,3,5-TCB, 1,2,4-TCB and 1,2,3-TCB; from 0.5 to 75 ng L{sup −1} for 1,2,4,5-TeCB, and PeCB; and from 1 to 75 ng L{sup −1} for 1,2,3,4-TeCB. The repeatability of the proposed method was evaluated at 10 ng L{sup −1} and 50 ng L{sup −1} spiking levels, and coefficients of variation ranged between 1.5 and 9.5% (n = 5). Limits of detection values were found between 93 and 301 pg L{sup −1}. Finally, tap, mineral and effluent water were selected as real water samples to assess method applicability. Relative recoveries varied between 86 and 110% showing negligible matrix effects. - Highlights: • A new extraction technique named Magnetic Headspace Adsorptive Extraction is presented. • Graphene oxide/iron oxide composite deposited on a neodymiun magnet as sorbent. • Sorbent of low cost, rapid and simple synthesis, easy manipulation and portability options. • Fast and efficient extraction and sensitive determination of chlorobenzenes in water samples.

  12. Detection system for a gas chromatograph

    Science.gov (United States)

    Hayes, John M.; Small, Gerald J.

    1984-01-01

    A method and apparatus are described for the quantitative analysis of vaporizable compounds, and in particular of polycyclic aromatic hydrocarbons which may be induced to fluoresce. The sample to be analyzed is injected into a gas chromatography column and is eluted through a narrow orifice into a vacuum chamber. The free expansion of the eluted sample into the vacuum chamber creates a supersonic molecular beam in which the sample molecules are cooled to the extent that the excited vibrational and rotational levels are substantially depopulated. The cooled molecules, when induced to fluoresce by laser excitation, give greatly simplified spectra suitable for analytical purposes. The laser induced fluorimetry provides great selectivity, and the gas chromatograph provides quantitative transfer of the sample to the molecular beam.

  13. A polythiophene-silver nanocomposite for headspace needle trap extraction.

    Science.gov (United States)

    Bagheri, Habib; Banihashemi, Solmaz; Jelvani, Samaneh

    2016-08-19

    A nanocomposite consisting of polythiophene-silver was prepared and implemented as a desired sorbent for headspace needle trap extraction. Colloidal silver nanoparticles (Ag NPs) with narrow size distribution and high stability were synthesized in water-in-oil microemulsion. This simple procedure was adapted to prepare highly monodispersed Ag NPs, starting from an initial synthesis in sodium bis(2-ethylhexyl) sulfosuccinate (AOT) reverse micelles. Polythiophene (PT) was synthesized by chemical oxidative polymerization in the presence of anhydrous ferric chloride while its polymeric structure was confirmed by Fourier transform infrared spectrometry (FTIR). Eventually, the prepared PT was dispersed in an AOT/n-decane solution containing Ag NPs for 1h in which the NPs were adsorbed on the polymer surface. The dynamic light scattering (DLS) analysis of NPs solution revealed that the monodisperse Ag NPs have been synthesized successfully with the size distribution below 10nm. Other instrumentations such as scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and atomic absorption spectrometry (AAS) confirmed the fabrication of the PT-Ag nanocomposite. The applicability of the synthesized sorbent was examined by needle trap extraction of some polycyclic aromatic hydrocarbons (PAHs) in aqueous samples in conjunction with gas chromatography-mass spectrometry detection (GC-MS). Important parameters influencing the extraction process were optimized. The linearity for all analytes was in the concentration range of 0.01-10ngmL(-1). The limits of detections were in the range of 0.002-0.01ngmL(-1), using time-scheduled selected ion monitoring (SIM) mode while the RSD% values (n=3) were all below 12%. The developed method was successfully applied to real water samples obtained from different rivers and Persian Gulf, while the relative recovery percentages were in the range of 85-103%. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Liquid chromatographic-mass spectrometric method for ...

    African Journals Online (AJOL)

    All intact and split tablets were individually dissolved in a water: methanol mixture (4:1), sonicated, filtered and further diluted with mobile phase. ... The results showed a good linear fit over the concentration range of 20 - 100 ng mL-1 for both analytes, with a correlation coefficient (r2) ≥ 0.999 and 0.998 for finasteride and ...

  15. Ultraviolet-photodiode array and high-performance liquid chromatographic/mass spectrometric studies on forced degradation behavior of glibenclamide and development of a validated stability-indicating method.

    Science.gov (United States)

    Bansal, Gulshan; Singh, Manjeet; Jindal, Kaur Chand; Singh, Saranjit

    2008-01-01

    A forced degradation study on glibenclamide was performed under conditions of hydrolysis, oxidation, dry heat, and photolysis and a high-performance column liquid chromatographic-ultraviolet (HPLC-UV) method was developed to study degradation behavior of the drug under the forced conditions. The degradation products formed under different forced conditions were characterized through isolation and subsequent infrared/nuclear magnetic resonance/mass spectral analyses, or through HPLC/mass spectrometric (HPLC/MS) studies. The drug degraded in 0.1 M HCI and water at 85 degrees C to a major degradation product, 5-chloro-2-methoxy-N-2-(4-sulfamoylphenyl)ethyl]benzamide (III), and to a minor product, 1-cyclohexyl-3-[[4-(2-aminoethyl)-phenyl]sulfonyl]urea (IV). Upon prolonged heating in the acid, the minor product IV disappeared, resulting in formation of 5-chloro-2-methoxy-benzoic acid (II) and an unidentified product (I). Heating of the drug in 0.1 M NaOH at 85 degrees C yielded II and IV as the major products and I and III as the minor products. The drug and the degradation products formed under different conditions were optimally resolved on a C18 column using ammonium acetate buffer (0.025 M, pH 3.5)-acetonitrile (45 + 55) mobile phase at a flow rate of 0.6 mL/min, with detection at 230 nm. The method was validated for linearity, precision, accuracy, and specificity. Limit of detection (LOD) and limit of quantitation (LOQ) values were also determined. The method could be successfully applied for simultaneous quantification of glibenclamide and the major product, III. The response of the method was linear in a narrow [0.4-10 micro/mL, correlation coefficient (r2) = 0.9982] and a wide (0.4-500 microg/mL, r2 = 0.9993) concentration range for glibenclamide, and in the concentration range of 0.025-50 microg/mL (r2 = 0.9998) for III. The method proved to be precise and accurate for both glibenclamide and III. It was specific for the drug and also selective for each

  16. Application of headspace solid phase microextraction for study of noncovalent interaction of borneol with human serum albumin

    Science.gov (United States)

    Hu, Liang; Chen, Dong-ying

    2009-01-01

    Aim: To investigate noncovalent interactions between borneol and human serum albumin (HSA) under near-physiological conditions. Methods: A 65-μm polydimethylsiloxane (PDMS) fiber was selected for sampling. The extraction temperature was kept at 37 °C, and the extraction time was optimized at 10 min. Borneol solutions of different concentrations were equilibrated in 600 μmol/L HSA and 67 mmol/L phosphate buffer solution (pH 7.4, 37 °C) for 24 h prior to solid phase microextraction (SPME) using headspace mode. The binding properties were obtained based on the calculation of extracted borneol amount using gas chromatography (GC) determination. Results: The headspace SPME extraction method avoided disturbance from the HSA binding matrix. The recovery showed good linearity for the borneol concentrations over the range of 0.4–16.3 μmol/L with a regression coefficient (R2) of 0.9998. The limit of detection and lower limit of quantitation were determined to be 0.01 μmol/L and 0.4 μmol/L, respectively. The binding constant and the percentage binding rate were estimated to be 2.4×103(mol/L)-1 and 59.5%, respectively. Conclusion: Headspace SPME coupled to GC is a simple, sensitive and rapid method for the study of borneol binding to HSA. The method may be applied in the determination of other protein binding properties in human plasma. PMID:19890364

  17. Validation of an analytical method for nitrous oxide (N2O) laughing gas by headspace gas chromatography coupled to mass spectrometry (HS-GC-MS): forensic application to a lethal intoxication.

    Science.gov (United States)

    Giuliani, N; Beyer, J; Augsburger, M; Varlet, V

    2015-03-01

    Drug abuse is a widespread problem affecting both teenagers and adults. Nitrous oxide is becoming increasingly popular as an inhalation drug, causing harmful neurological and hematological effects. Some gas chromatography-mass spectrometry (GC-MS) methods for nitrous oxide measurement have been previously described. The main drawbacks of these methods include a lack of sensitivity for forensic applications; including an inability to quantitatively determine the concentration of gas present. The following study provides a validated method using HS-GC-MS which incorporates hydrogen sulfide as a suitable internal standard allowing the quantification of nitrous oxide. Upon analysis, sample and internal standard have similar retention times and are eluted quickly from the molecular sieve 5Å PLOT capillary column and the Porabond Q column therefore providing rapid data collection whilst preserving well defined peaks. After validation, the method has been applied to a real case of N2O intoxication indicating concentrations in a mono-intoxication. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Simple analysis of naphthalene in human whole blood and urine by headspace capillary gas chromatography with large volume injection

    OpenAIRE

    Watanabe, Kanako; Hasegawa, Koutaro; Yamagishi, Itaru; Nozawa, Hideki; Suzuki, Osamu

    2009-01-01

    Naphthalene is still being sold as a moth repellant; there is a possibility that accidental ingestion of such a product by a small infant causes serious poisoning. In this communication, a very simple method for analysis of naphthalene in human whole blood and urine by headspace gas chromatography (GC) has been presented. It neither needs solid-phase microextraction nor cryogenic trapping devices, but needs only a conventional capillary GC instrument with flame ionization detection. The advan...

  19. Accurate determination of residual acrylic acid in superabsorbent polymer of hygiene products by headspace gas chromatography.

    Science.gov (United States)

    Zhang, Shu-Xin; Chai, Xin-Sheng; Jiang, Ran

    2017-02-17

    This work reports on a method for the determination of residual acrylic acid (AA) in the superabsorbent polymers for hygiene products by headspace analysis. It was based on water extraction for the polymer sample at a room temperature for 50min. Then, the AA in the extractant reacted with bicarbonate solution in a closed headspace sample vial, from which the carbon dioxide generated from the reaction (within 20min at 70°C) was detected by gas chromatography (GC). It was found that there is adsorption partition equilibrium of AA between solid-liquid phases. Therefore, an equation for calculating the total AA content in the original polymers sample was derived based on the above phase equilibrium. The results show that the HS-GC method has good precision (RSD<2.51%) and good accuracy (recoveries from 93 to 105%); the limit of quantification (LOQ) was 373mg/kg. The present method is rapid, accurate, and suitable for determining total residual acrylic acid in a wide variety of applications from processing of superabsorbent polymer to commercial products quality control. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. A liquid chromatographic-mass spectrometric (LC-MS) method for the analysis of the bis-pyridinium oxime ICD-585 in plasma: application in a guinea pig model.

    Science.gov (United States)

    Capacio, B R; Dusick, B; Smith, J R; McDonough, J H; Shih, T-M

    2010-05-15

    In recent animal studies, several novel oxime compounds that are better than 2-PAM as antidotes against selected organophosphate (OP) nerve agents have been identified. The purpose of this study was to develop and validate a liquid chromatographic-mass spectrometric (LC-MS) method for analysis of the bis-pyridinium oxime ICD-585 (1-(2-hydroxyiminomethylpyridinium)-3-(4-carbamoylpyridinium)-propane) in plasma and to establish the utility of the method in a guinea pig model. Calibration curves were prepared using ICD-585-spiked plasma at concentrations from 0.156 to 10 microg/ml. Curves were run over a 1-month time frame and a total of 13 (n=13) were generated. The lower limit of quantification (LLOQ) was determined to be 0.216 microg/ml. Intra- and inter-day variability was assessed by studying precision and accuracy. For intra-day studies, data from the precision determinations indicated that the % CV's ranged from 4.28 to 14.98%. The % error in the accuracy assessments ranged from -8.73 to 4.61%. For inter-day studies, precision data ranged from 3.53 to 13.20%. The % error in the accuracy assessments ranged from 0.39 to 13.77%. Room temperature, freeze-thaw and autosampler stability was also examined. For all 3 stability studies, the compound remained within +/-15% of the initial analysis. Application of the method was demonstrated by analyzing samples from guinea pigs challenged with sarin (GB) or cyclosarin (GF) (1x LD(50)) followed with intramuscular ICD-585 (58 microM/kg, 21.8 mg/kg). At 55 min after oxime administration, mean (+/-SD) plasma concentrations were 15.98 (+/-4.88)microg/ml and 14.57 (+/-3.70) microg/ml in GB- and GF-exposed animals, respectively. In summary, studies have been carried out to verify the sensitivity, precision and accuracy of the assay as well as the stability of the analyte under various conditions. The method has been demonstrated to be applicable to the analysis of plasma from nerve agent-exposed guinea pigs. Published by Elsevier

  1. Ion chromatographic determination of cyanate in saline gold processing samples.

    Science.gov (United States)

    Black, S B; Schulz, R S

    1999-09-03

    An ion chromatographic method was developed for the determination of cyanate (CNO-) in saline gold processing samples. The method is based on the use of a very weak-eluting buffer (5 mM sodium borate) and a Dionex AS4A-SC anion-exchange column. This weak-eluting buffer facilitates the wide chromatographic separation of chloride (Cl-) from CNO-. After CNO- has been eluted, the switch to 1.8 mM Na2CO3-1.7 mM NaHCO3 buffer allows the fast elution of other major inorganic and organic anions. Validation of this method, including identification of interferences, has shown that this method is reliable, accurate, sensitive (detection limit, 0.1 mg/l CNO-) and reproducible.

  2. Determination of total acid content in biomass hydrolysates by solvent-assisted and reaction based headspace gas chromatography.

    Science.gov (United States)

    Huang, Liu-Lian; Hu, Hui-Chao; Chen, Li-Hui

    2015-11-27

    This work reports on a novel method for the determination of total acid (TA) in biomass hydrolysates by a solvent-assisted and reaction-based headspace gas chromatography (HS-GC). The neutralization reaction between the acids in hydrolysates and bicarbonate in an ethanol (50%) aqueous solution was performed in a closed headspace sample vial, from which the carbon dioxide generated from the reaction was detected by HS-GC. It was found that the addition of ethanol can effectively eliminate the precipitation of some organic acids in the biomass hydrolysates. The results showed that the reaction and headspace equilibration can be achieved within 45min at 70°C; the method has a good precision (RSD<3.27%) and accuracy (recovery of 97.4-105%); the limit of quantification is 1.36μmol. The present method is quite suitable to batch analysis of TA content in hydrolysate for the biorefinery related research. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Analysis of ammonium nitrate headspace by on-fiber solid phase microextraction derivatization with gas chromatography mass spectrometry.

    Science.gov (United States)

    Lubrano, Adam L; Andrews, Benjamin; Hammond, Mark; Collins, Greg E; Rose-Pehrsson, Susan

    2016-01-15

    A novel analytical method has been developed for the quantitation of trace levels of ammonia in the headspace of ammonium nitrate (AN) using derivatized solid phase microextraction (SPME) fibers with gas chromatography mass spectrometry (GC-MS). Ammonia is difficult to detect via direct injection into a GC-MS because of its low molecular weight and extreme polarity. To circumvent this issue, ammonia was derivatized directly onto a SPME fiber by the reaction of butyl chloroformate coated fibers with the ammonia to form butyl carbamate. A derivatized externally sampled internal standard (dESIS) method based upon the reactivity of diethylamine with unreacted butyl chloroformate on the SPME fiber to form butyl diethylcarbamate was established for the reproducible quantification of ammonia concentration. Both of these compounds are easily detectable and separable via GC-MS. The optimized method was then used to quantitate the vapor concentration of ammonia in the headspace of two commonly used improvised explosive device (IED) materials, ammonium nitrate fuel oil (ANFO) and ammonium nitrate aluminum powder (Ammonal), as well as identify the presence of additional fuel components within the headspace. Published by Elsevier B.V.

  4. [Determination of five synthetic musks in perfume by headspace solid-phase microextraction and gas chromatography-mass spectrometry].

    Science.gov (United States)

    Wang, Guannan; Tang, Hua; Chen, Dazhou; Feng, Jie; Li, Lei

    2012-02-01

    A method for headspace solid-phase microextraction (HS-SPME), followed by gas chromatography-mass spectrometry (GC-MS) analysis was established for the determination of five commonly used synthetic musks in perfume. Two polycyclic musks (celestolide and tonalide) and three nitro musks (musk ambrette, musk xylene and musk ketone) were used as analytes in the optimization of the analytical method. Six parameters, such as the extraction temperature, equilibrium time, extraction time, desorption time, injector temperature and solution of salting out, were optimized by exposing the 65 microm polydimethylsiloxane-divinyl-benzene (PDMS-DVB) fiber to the headspace of magnetically stirred (600 r/min) sample. According to the results of the optimization experiments, the following conclusion can be drawn: The water-diluted sample in a 10 mL headspace-vial was efficiently extracted for 20 min after the system was equilibrated for 3 min at 60 degrees C. After extraction, the fiber was immediately inserted into the GC injector and desorbed at 250 degrees C for 3 min. The spiked recoveries were in the range of 82.0% - 103.3% and the relative standard deviations (RSDs) were between 1.8% and 9.4%. Meanwhile, the limits of detection (LODs) ranged from 0.6 ng/g to 2.1 ng/g. This method is characterized by rapidity, high sensitivity, good linearity and repeatability for all the target compounds. It is applicable to the analysis of synthetic musks in perfumes.

  5. Evaluation des méthodes chimiques, spectroscopiques et chromatographiques utilisables pour l'identification des polluants pétroliers en mer Evaluation of Chemical, Spectroscopic and Chromatographic Methods Used to Identify Offshore Oil Pollutants

    Directory of Open Access Journals (Sweden)

    Albaigés J.

    2006-11-01

    Full Text Available Dans cet article on passe en revue les différentes méthodes utilisables pour l'identification des principaux polluants pétroliers de la mer par l'analyse quantitativé de leurs « marqueurs passifs x (soufre, azote, nickel, vanadium, paraffine et asphaltènes et la détermination d'autres caractéristiques intrinsèques. II s'agit de méthodes chimiques, spectroscop iques (infrarouge, ultraviolette et chromatographiques (chromatographie en phase gazeuse à haute résolution avec détection par ionisation de flamme, photométrie de flamme et capture d'électrons. Les mesures ont concerné une grande variété de produits susceptibles de polluer la côte méditerranéenne espagnole - pétrole brut des gisements offshore d'Amposta et de Castellôn; - pétroles bruts importés traités dans les raffineries côtières (Boscan, Es Sider, Kuwait, Arabian light, etc.; - fractions lourdes provenant de ces raffineries (fuel-cils, asphaltes, lubrifiants; - polluants réels; - échantillons altérés artificiellement en laboratoire afin de mettre en évidence l'action progressive des éléments naturels. On a trouvé que les méthodes les plus intéressantes étaient : - le dosage chimique du soufre, du nickel et du vanadium; - la spectroscopie infrarouge; - la chromatographie en phase gazeuse à haute résolution avec détection par ionisation et photométrie de flamme. This article reviews the different methods that con be used to identify the leading petroleum pollutants of the sea by quantitative analysis of their a passive markers » (sulfur, nitrogen, nickel, vanadium, paraffin, asphaltenes and by determining other intrinsic properties. These methods are chemical, spectroscopic (infrared, ultraviolet and chromatographic (high-resolution gas chromatography with flame ionization detection, flame photometry and electron capture. Measurements were made of a great variety of products capable of polluting the Spanish Mediterranean coast, including

  6. Quantitative Analysis of Bioactive Compounds from Aromatic Plants by Means of Dynamic Headspace Extraction and Multiple Headspace Extraction-Gas Chromatography-Mass Spectrometry

    NARCIS (Netherlands)

    Omar, Jone; Olivares, Maitane; Alonso, Ibone; Vallejo, Asier; Aizpurua-Olaizola, Oier; Etxebarria, Nestor

    2016-01-01

    Seven monoterpenes in 4 aromatic plants (sage, cardamom, lavender, and rosemary) were quantified in liquid extracts and directly in solid samples by means of dynamic headspace-gas chromatography-mass spectrometry (DHS-GC-MS) and multiple headspace extraction-gas chromatography-mass spectrometry

  7. Métodos de extração e/ou concentração de compostos encontrados em fluidos biológicos para posterior determinação cromatográfica Methods of extraction and/or concentration of compounds found in biological fluids for subsequent chromatographic determination

    Directory of Open Access Journals (Sweden)

    Sonia C. N. Queiroz

    2001-02-01

    Full Text Available When organic compounds present in biological fluids are analysed by chromatographic methods, it is generally necessary to carry out a prior sample preparation due the high complexity of this type of sample, especially when the compounds to be determinated are found in very low concentrations. This article describes some of the principal methods for sample preparation in analyses of substances present in biological fluids. The methods include liquid-liquid extraction, solid phase extraction, supercritical fluid extraction and extraction using solid and liquid membranes. The advantages and disadvantages of these methods are discussed.

  8. Validação de métodos cromatográficos de análise: um experimento de fácil aplicação utilizando cromatografia líquida de alta eficiência (CLAE e os princípios da "Química Verde" na determinação de metilxantinas em bebidas Validation of chromatographic methods: an experiment using HPLC and Green Chemistry in methylxanthines determination

    Directory of Open Access Journals (Sweden)

    Nádia Machado de Aragão

    2009-01-01

    Full Text Available The validation of analytical methods is an important step in quality control. The main objective of this study is to propose an HPLC experiment to verify the parameters of validation of chromatographic methods, based on green chemistry principles, which can be used in experimental courses of chemistry and related areas.

  9. The effect of surfactant on headspace single drop microextraction for the determination of some volatile aroma compounds in citronella grass and lemongrass leaves by gas chromatography

    Science.gov (United States)

    A rapid method for the determination of some volatile aromatic compounds (VACs), including citronellal, citronellol, neral, geranial, geraniol, and eugenol in citronella grass and lemongrass leaves, was developed using surfactant as a surface tension modifier while performing headspace single drop m...

  10. Chromatographic Separation of Vitamin E Enantiomers

    Directory of Open Access Journals (Sweden)

    Ju-Yen Fu

    2017-02-01

    Full Text Available Vitamin E is recognized as an essential vitamin since its discovery in 1922. Most vegetable oils contain a mixture of tocopherols and tocotrienols in the vitamin E composition. Structurally, tocopherols and tocotrienols share a similar chromanol ring and a side chain at the C-2 position. Owing to the three chiral centers in tocopherols, they can appear as eight different stereoisomers. Plant sources of tocopherol are naturally occurring in the form of RRR while synthetic tocopherols are usually in the form of all-racemic mixture. Similarly, with only one chiral center, natural tocotrienols occur as the R-isoform. In this review, we aim to discuss a few chromatographic methods that had been used to separate the stereoisomers of tocopherols and tocotrienols. These methods include high performance liquid chromatography, gas chromatography and combination of both. The review will focus on method development including selection of chiral columns, detection method and choice of elution solvent in the context of separation efficiency, resolution and chiral purity. The applications for separation of enantiomers in vitamin E will also be discussed especially in terms of the distinctive biological potency among the stereoisoforms.

  11. Chromatographic Separations of Enantiomers and Underivatized Oligosaccharides

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ying [Iowa State Univ., Ames, IA (United States)

    2004-01-01

    My graduate research has focused on separation science and bioanalytical analysis, which emphasized in method development. It includes three major areas: enantiomeric separations using high performance liquid chromatography (HPLC), Super/subcritical fluid chromatography (SFC), and capillary electrophoresis (CE); drug-protein binding behavior studies using CE; and carbohydrate analysis using liquid chromatograph-electrospray ionization mass spectrometry (LC-ESI-MS). Enantiomeric separations continue to be extremely important in the pharmaceutical industry. An in-depth evaluation of the enantiomeric separation capabilities of macrocyclic glycopeptides CSPs with SFC mobile phases was investigated using a set of over 100 chiral compounds. It was found that the macrocyclic based CSPs were able to separate enantiomers of various compounds with different polarities and functionalities. Seventy percent of all separations were achieved in less than 4 min due to the high flow rate (4.0 ml/min) that can be used in SFC. Drug-protein binding is an important process in determining the activity and fate of a drug once it enters the body. Two drug/protein systems have been studied using frontal analysis CE method. More sensitive fluorescence detection was introduced in this assay, which overcame the problem of low sensitivity that is common when using UV detection for drug-protein studies. In addition, the first usage of an argon ion laser with 257 nm beam coupled with CCD camera as a frontal analysis detection method enabled the simultaneous observation of drug fluorescence as well as the protein fluorescence. LC-ESI-MS was used for the separation and characterization of underivatized oligosaccharide mixtures. With the limits of detection as low as 50 picograms, all individual components of oligosaccharide mixtures (up to 11 glucose-units long) were baseline resolved on a Cyclobond I 2000 column and detected using ESI-MS. This system is characterized by high chromatographic

  12. Determination of volatile organic compounds in water by headspace solid-phase microextraction gas chromatography coupled to tandem mass spectrometry with triple quadrupole analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Cervera, M.I. [Research Institute for Pesticides and Water, University Jaume I, Avda. Sos Baynat, E-12071 Castellon (Spain); Beltran, J., E-mail: joaquim.beltran@uji.es [Research Institute for Pesticides and Water, University Jaume I, Avda. Sos Baynat, E-12071 Castellon (Spain); Lopez, F.J.; Hernandez, F. [Research Institute for Pesticides and Water, University Jaume I, Avda. Sos Baynat, E-12071 Castellon (Spain)

    2011-10-17

    Highlights: {yields} Employing a statistical optimization improves results reducing experiments. {yields} Use of MS (QqQ) allows high sensitivity determination and improves identification capabilities. {yields} Using Q/q intensity ratios is a powerful tool to ensure compound identification. {yields} HS SPME GC-MS/MS method allows determination of VOCs in complex matrix water samples. - Abstract: In the present work, a rapid method with little sample handling has been developed for determination of 23 selected volatile organic compounds in environmental and wastewater samples. The method is based on headspace solid-phase microextraction (SPME) followed by gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) determination using triple quadrupole analyzer (QqQ) in electron ionization mode. The best conditions for extraction were optimised with a factorial design taking into account the interaction between different parameters and not only individual effects of variables. In the optimized procedure, 4 mL of water sample were extracted using a 10 mL vial and adding 0.4 g NaCl (final NaCl content of 10%). An SPME extraction with carboxen/polydimethylsiloxane 75 {mu}m fiber for 30 min at 50 deg. C (with 5 min of previous equilibration time) with magnetic stirring was applied. Chromatographic determination was carried out by GC-MS/MS working in Selected Reaction Monitoring (SRM) mode. For most analytes, two MS/MS transitions were acquired, although for a few compounds it was difficult to obtain characteristic abundant fragments. In those cases, a pseudo selected reaction monitoring (pseudo-SRM) with three ions was used instead. The intensity ratio between quantitation (Q) and confirmation (q) signals was used as a confirmatory parameter. The method was validated by means of recovery experiments (n = 6) spiking mineral water samples at three concentration levels (0.1, 5 and 50 {mu}g L{sup -1}). Recoveries between 70% and 120% were generally obtained with

  13. Determination of phthalate esters in drinking water and edible vegetable oil samples by headspace solid phase microextraction using graphene/polyvinylchloride nanocomposite coated fiber coupled to gas chromatography-flame ionization detector.

    Science.gov (United States)

    Amanzadeh, Hatam; Yamini, Yadollah; Moradi, Morteza; Asl, Yousef Abdossalmi

    2016-09-23

    In the current study, a graphene/polyvinylchloride nanocomposite was successfully coated on a stainless steel substrate by a simple dip coating process and used as a novel headspace solid phase microextraction (HS-SPME) fiber for the extraction of phthalate esters (PEs) from drinking water and edible vegetable oil samples. The prepared SPME fibers exhibited high extractability for PEs (due to the dominant role of π-π stacking interactions and hydrophobic effects) yielding good sensitivity and precision when followed by a gas chromatograph with a flame ionization detector (GC-FID). The optimization strategy of the extraction process was carried out using the response surface method based on a central composite design. The developed method gave a low limit of detection (0.06-0.08μgL(-1)) and good linearity (0.2-100μgL(-1)) for the determination of the PEs under the optimized conditions (extraction temperature, 70±1°C; extraction time, 35min; salt concentration, 30% w/v; stirring rate, 900rpm; desorption temperature, 230°C; and desorption time, 4min) whereas the repeatability and fiber-to-fiber reproducibility were in the range 6.1-7.8% and 8.9-10.2%, respectively. Finally, the proposed method was successfully applied to the analysis of PEs in drinking water and edible oil samples with good recoveries (87-112%) and satisfactory precisions (RSDs<8.3%), indicating the absence of matrix effects in the proposed HS-SPME method. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. An ionic liquid as a solvent for headspace single drop microextraction of chlorobenzenes from water samples.

    Science.gov (United States)

    Vidal, Lorena; Psillakis, Elefteria; Domini, Claudia E; Grané, Nuria; Marken, Frank; Canals, Antonio

    2007-02-12

    A headspace single-drop microextraction (HS-SDME) procedure using room temperature ionic liquid and coupled to high-performance liquid chromatography capable of quantifying trace amounts of chlorobenzenes in environmental water samples is proposed. A Plackett-Burman design for screening was carried out in order to determine the significant experimental conditions affecting the HS-SDME process (namely drop volume, aqueous sample volume, stirring speed, ionic strength, extraction time and temperature), and then a central composite design was used to optimize the significant conditions. The optimum experimental conditions found from this statistical evaluation were: a 5 microL microdrop of 1-butyl-3-methylimidazolium hexafluorophosphate, exposed for 37 min to the headspace of a 10 mL aqueous sample placed in a 15 mL vial, stirred at 1580 rpm at room temperature and containing 30% (w/v) NaCl. The calculated calibration curves gave a high level of linearity for all target analytes with correlation coefficients ranging between 0.9981 and 0.9997. The repeatability of the proposed method, expressed as relative standard deviation, varied between 1.6 and 5.1% (n=5). The limits of detection ranged between 0.102 and 0.203 microg L(-1). Matrix effects upon extraction were evaluated by analysing spiked tap and river water as well as effluent water samples originating from a municipal wastewater treatment plant.

  15. Recovery of oxygenated ignitable liquids by zeolites, Part II: Dual-mode heated passive headspace extraction.

    Science.gov (United States)

    Rodgers, Corissa L; St Pierre, Kathryne A; Hall, Adam B

    2014-07-01

    Previous studies performed by our research group have suggested that zeolites are a suitable adsorbent for the recovery of oxygenates from fire debris through heated passive headspace extraction. Zeolite 13X, in particular, has been shown to be effective for recovering analytes with molecular diameters smaller than 10Å. The primary aim of this study was to evaluate the addition of zeolite 13X to heated headspace extraction for the recovery of ignitable liquids. Comparative recoveries of petroleum and alcohol-based ignitable liquid mixtures were studied utilizing activated charcoal strips and zeolites, individually and in tandem. In the presence of both adsorption media within the same sample can, activated charcoal strips recovered the majority of gasoline components, while zeolites recovered the majority of oxygenated compounds. This phenomenon was attributed to the size exclusion properties, polarity, and available surface area of zeolites. This research supports the use of zeolites with activated charcoal strips in a "dual-mode" preparation for casework in which the presence of an ignitable liquid is suspected. The described method allows for the recovery and concentration of ignitable liquid residues in a single extraction procedure, whether the ignitable liquid is petroleum-based or oxygenated in nature. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  16. Chromatographic, capillary electrophoretic and capillary electrochromatographic techniques in the analysis of flavonoids.

    Science.gov (United States)

    Molnár-Perl, I; Füzfai, Zs

    2005-05-06

    An overview is presented of chromatographic methods currently in use to determine flavonoids, including free aglycones, their corresponding glycosides, one by one, and, in the presence of each other. As a basis of selection, the following approaches can be distinguished: critical evaluation of the preliminary steps (extraction/isolation and hydrolysis) as well as the separation, identification and quantitation of constituents both on the basic research level and/or subsequently to various work up procedures. Chromatographic techniques were discussed after extraction/isolation of various flavonoids from several natural matrices. Papers were classified and compared from analytical point of view, primarily on the chromatographic, secondly on the detection techniques applied.

  17. Statistical designs and response surface techniques for the optimization of chromatographic systems.

    Science.gov (United States)

    Ferreira, Sergio Luis Costa; Bruns, Roy Edward; da Silva, Erik Galvão Paranhos; Dos Santos, Walter Nei Lopes; Quintella, Cristina Maria; David, Jorge Mauricio; de Andrade, Jailson Bittencourt; Breitkreitz, Marcia Cristina; Jardim, Isabel Cristina Sales Fontes; Neto, Benicio Barros

    2007-07-27

    This paper describes fundamentals and applications of multivariate statistical techniques for the optimization of chromatographic systems. The surface response methodologies: central composite design, Doehlert matrix and Box-Behnken design are discussed and applications of these techniques for optimization of sample preparation steps (extractions) and determination of experimental conditions for chromatographic separations are presented. The use of mixture design for optimization of mobile phases is also related. An optimization example involving a real separation process is exhaustively described. A discussion about model validation is presented. Some applications of other multivariate techniques for optimization of chromatographic methods are also summarized.

  18. Fiber-based solid phase microextraction using fused silica lined bottles to collect, store, and stabilize a multianalyte headspace gas sample for offline analyses.

    Science.gov (United States)

    Harvey, Chris A; Carter, J Chance; Ertel, John R; Alviso, Cindy T; Chinn, Sarah C; Maxwell, Robert S

    2015-07-03

    We have developed a solid phase microextraction (SPME) sampling method using fused silica lined bottles (400 ml) to collect, store, and stabilize a headspace subsample from the source for subsequent offline, repetitive analyses of the gas using fiber-based SPME. The method enables long-term stability for repeated offline analysis of the organic species collected from the source headspace and retains all the advantages of fiber SPME sampling (e.g. rapid extraction, solvent free, simple and inexpensive) while providing additional advantages. Typically, the analytes collected on the SPME fiber must be desorbed and analyzed immediately to mitigate analyte loss or contamination. The new SPME sampling method, conducted offline using carboxen/polydimethylsiloxane (carboxen/PDMS - 85 μm) coated fibers, has been shown to be identical to in situ SPME sampling of a headspace acquired from an 80 component organic matrix with reproducibility demonstrated to be less than %RSD=7.0% for replicate samples measured over a 30-day period. In addition, repetitive samplings from one headspace aliquot are possible using one or more fibers and fiber types as well as quantitative options such as internal standard addition as demonstrated in a feasibility study using a benzene/toluene/xylene (BTX; 1 ppmv) certified gas standard, in which the SPME measurement precision (%RSD) was improved by a factor of 1.5-1.9 compared to the use of an external standard. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Application of headspace analysis to the study of sorption of hydrophobic organic chemicals to α-Al2O3

    Science.gov (United States)

    Pelinger, Judith A.; Eisenreich, Steven J.; Capel, Paul D.

    1993-01-01

    The sorption of hydrophobic organic chemicals (HOCs) to ??-Al2O3 was investigated with a headspace analysis method. The semiautomated headspace analyzer gave rapid, precise, and accurate results for a homologous series alkylbenzenes even at low percentages of solute mass sorbed (3-50%). Sorption experiments carried out with benzene alone indicated weak interactions with well-characterized aluminum oxide, and a solids concentration effect was observed. When the sorption coefficients for benzene alone obtained by headspace analysis were extrapolated up to the solids concentrations typically used in batch sorption experiments, the measured sorption coefficients agreed with reported sorption coefficients for HOCs and sediments of low fractional organic carbon content. Sorbed concentrations increased exponentially with aqueous concentration in isotherms with mixtures of alkylbenzenes, indicating solute-solute interactions at the mineral surface. Sorption was, however, greater than predicted for partitioning of a solute between its pure liquid phase and water, indicating additional influences of the surface and/or the structured liquid near the mineral surface. ?? 1993 American Chemical Society.

  20. Determination of chlorophenols in landfill leachate using headspace sampling with ionic liquid-coated solid-phase microextraction fibers combined with gas chromatography-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Tse-Tsung; Chen, Chung-Yu [Department of Chemistry, National Chung Hsing University, Taichung 40227, Taiwan (China); Li Zuguang [Department of Chemistry, National Chung Hsing University, Taichung 40227, Taiwan (China); College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310014, Zhejiang (China); Yang, Thomas Ching-Cherng [Department of Chemistry, National Kaohsiung Normal University, Kaohsiung 82444, Taiwan (China); Lee, Maw-Rong, E-mail: mrlee@dragon.nchu.edu.tw [Department of Chemistry, National Chung Hsing University, Taichung 40227, Taiwan (China)

    2012-01-27

    Highlights: Black-Right-Pointing-Pointer Ionic liquid (IL), ([C{sub 4}MIM][PF{sub 6}]), was rapid synthesized by microwave radiation. Black-Right-Pointing-Pointer Trace chlorophenols in landfill leachate were extract by SPME coated IL. Black-Right-Pointing-Pointer The IL-coated SPME-GC/MS method is low-cost, solvent-free and sensitive. - Abstract: A new microextraction technique based on ionic liquid solid-phase microextraction (IL-SPME) was developed for determination of trace chlorophenols (CPs) in landfill leachate. The synthesized ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([C{sub 4}MIM][PF{sub 6}]), was coated onto the spent fiber of SPME for extraction of trace CPs. After extraction, the absorbed analytes were desorbed and quantified using gas chromatography-mass spectrometry (GC/MS). The term of the proposed method is as ionic liquid-coated of solid-phase microextraction combined with gas chromatography-mass spectrometry (IL-SPME-GC/MS). No carryover effect was found, and every laboratory-made ionic liquids-coated-fiber could be used for extraction at least eighty times without degradation of efficiency. The chlorophenols studied were 2,4-dichlorophenol (2,4-DP), 2,4,6-trichlorophenol (2,4,6-TCP), 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP), and pentachlorophenol (PCP). The best results of chlorophenols analysis were obtained with landfill leachate at pH 2, headspace extraction for 4 min, and thermal desorption with the gas chromatograph injector at 240 Degree-Sign C for 4 min. Linearity was observed from 0.1 to 1000 {mu}g L{sup -1} with relative standard deviations (RSD) less than 7% and recoveries were over 87%. The limit of detection (LOD) for pentachlorophenol was 0.008 {mu}g L{sup -1}. The proposed method was tested by analyzing landfill leachate from a sewage farm. The concentrations of chlorophenols were detected to range from 1.1 to 1.4 {mu}g L{sup -1}. The results demonstrate that the IL-SPME-GC/MS method is highly effective in

  1. Headspace solid-phase microextraction of higher fatty acid ethyl esters in white rum aroma.

    Science.gov (United States)

    Pino, J; Martí, M P; Mestres, M; Pérez, J; Busto, O; Guasch, J

    2002-04-19

    Fatty acid ethyl esters are the main components of rum aroma and play an important sensorial impact in these distilled alcoholic beverages. Herein, a method for analysing these volatile compounds is described. It involves a separation and concentration step using headspace solid-phase microextraction and determination by capillary gas chromatography using flame ionisation detection. The influence of different parameters related to the isolation and concentration step, such as ethanol concentration, ionic strength, sample volume, time and temperature of extraction, was studied. The developed method enabled recoveries >91% for the analyzed compounds with limits of detection between 0.007 and 0.027 mg/l, all of them lower than the range of concentrations found in rum samples. The method was successfully applied to the analysis of fatty acid ethyl esters in different commercial white rums.

  2. [Measurement of acetonitrile in blood and urine by head-space gas chromatography].

    Science.gov (United States)

    Luo, Ru-Xin; Zhuo, Xian-Yi; Shen, Bao-Hua

    2012-12-01

    To establish the method for measurement of acetonitrile in blood and urine by head-space gas chromatography. DB-ALC1 (30 m x 320 microm x 1.8 microm) and DB-ALC2 (30 m x 320 microm x 1.2 microm) capillary column were used to measure the acetonitrile in blood and urine with the isopropanol as internal standard reference. The limits of detection of acetonitrile in both blood and urine were 0.5 microg/mL, with a linear range of 5-1000 microg/mL (r = 0.999).The accuracy of this method was 93.2%-98.0%. The RSD for the intra-day and inter-day were less than 3.7%. The method is capable for measurement analysis of acetonitrile in blood and urine.

  3. Parameters optimization using experimental design for headspace solid phase micro-extraction analysis of short-chain chlorinated paraffins in waters under the European water framework directive.

    Science.gov (United States)

    Gandolfi, F; Malleret, L; Sergent, M; Doumenq, P

    2015-08-07

    The water framework directives (WFD 2000/60/EC and 2013/39/EU) force European countries to monitor the quality of their aquatic environment. Among the priority hazardous substances targeted by the WFD, short chain chlorinated paraffins C10-C13 (SCCPs), still represent an analytical challenge, because few laboratories are nowadays able to analyze them. Moreover, an annual average quality standards as low as 0.4μgL(-1) was set for SCCPs in surface water. Therefore, to test for compliance, the implementation of sensitive and reliable analysis method of SCCPs in water are required. The aim of this work was to address this issue by evaluating automated solid phase micro-extraction (SPME) combined on line with gas chromatography-electron capture negative ionization mass spectrometry (GC/ECNI-MS). Fiber polymer, extraction mode, ionic strength, extraction temperature and time were the most significant thermodynamic and kinetic parameters studied. To determine the suitable factors working ranges, the study of the extraction conditions was first carried out by using a classical one factor-at-a-time approach. Then a mixed level factorial 3×2(3) design was performed, in order to give rise to the most influent parameters and to estimate potential interactions effects between them. The most influent factors, i.e. extraction temperature and duration, were optimized by using a second experimental design, in order to maximize the chromatographic response. At the close of the study, a method involving headspace SPME (HS-SPME) coupled to GC/ECNI-MS is proposed. The optimum extraction conditions were sample temperature 90°C, extraction time 80min, with the PDMS 100μm fiber and desorption at 250°C during 2min. Linear response from 0.2ngmL(-1) to 10ngmL(-1) with r(2)=0.99 and limits of detection and quantification, respectively of 4pgmL(-1) and 120pgmL(-1) in MilliQ water, were achieved. The method proved to be applicable in different types of waters and show key advantages, such

  4. Chromatographic analysis of penicillins in pharmaceutical formulations and biological fluids.

    Science.gov (United States)

    Samanidou, Victoria F; Evaggelopoulou, Evaggelia N; Papadoyannis, Ioannis N

    2006-08-01

    Natural penicillin (benzylpenicillin) is the oldest antibiotic observed by Alexander Fleming in 1928. To broaden its spectrum of activity, natural penicillin was modified, giving rise to a group of antibiotics under the name 'penicillins'. Although an increasing number of bacteria appear to be resistant to them, penicillins are used to treat a variety of bacterial infections including Gram-positive, Gram-negative aerobic and anaerobic bacteria. Consequently, they are widely used in human and veterinary medicine to prevent and treat diseases. This review covers the analytical methodologies, mainly chromatographic, employed to the penicillins determination in pharmaceutical formulations, biological fluids and in production-scale fermentations reported in the literature. Results of published assays are comparatively presented focusing on sample preparation regarding isolation and purification, chromatographic conditions and method validation. Information on chemical structure, spectrum of activity and action mechanism of common penicillins has also been given.

  5. Development of a chromatographic method for the study of the stability and compatibility of Mexican fuel oils; Desarrollo de un metodo cromatografico para el estudio de estabilidad y compatibilidad de combustoleos mexicanos

    Energy Technology Data Exchange (ETDEWEB)

    Blass Amador, Georgina; Panama Tirado, Luz Angelica [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1992-11-01

    In Mexico, the largest part of the generated electric energy comes from the use of residual heavy oils known as fuel oils which have suffered quality degradation due to a combination of factors, among which stands out the changes in the refining process. It is necessary to develop methods capable of indicating the instability (formation of sediment or viscosity increase during storage or heating) or incompatibility (formation of sediment in mixing two or more fuel oils) of the fuel oils employed in fossil fuel power plants. This work objective was to develop an alternative test for the study of the compatibility and/or stability of Mexican fuel oils using high resolution liquid chromatography (CLAR) and so to determine structural aspects of the fuel oil that determine its stability. Since the formation of sediments occurs when the dissolving ability of the fuel is inadequate to keep the asphaltenes in solution, it is important to know the solvent power degree or aromaticity of the diluent; so, in the first part of this work the attention was centered in the determination of the profile of aromatic compounds of the fuel oil diluents, the other part was dedicated to the determination of the distribution profile the molecular weights of the asphaltenes present in the fuel oils. The profiles of the aromatic fraction, as well as of the molecular weight distribution were determined using liquid chromatography, in which a variety of columns and solvents were used. A combination of routine tests was accomplished, such as asphaltenes content, toluene equivalence, viscosity, etc., in order to obtain correlation with the chromatographic method developed. In this article it is only discussed the section corresponding to the obtainment of the profile of aromatics content in the fuel oils. It has been found a correlation among the asphaltenes content, toluene equivalence, aromaticity profiles and stability. As a direct consequence, it is expected to be able to predict the

  6. Quantitative fingerprinting by headspace--two-dimensional comprehensive gas chromatography-mass spectrometry of solid matrices: some challenging aspects of the exhaustive assessment of food volatiles.

    Science.gov (United States)

    Nicolotti, Luca; Cordero, Chiara; Cagliero, Cecilia; Liberto, Erica; Sgorbini, Barbara; Rubiolo, Patrizia; Bicchi, Carlo

    2013-10-10

    The study proposes an investigation strategy that simultaneously provides detailed profiling and quantitative fingerprinting of food volatiles, through a "comprehensive" analytical platform that includes sample preparation by Headspace Solid Phase Microextraction (HS-SPME), separation by two-dimensional comprehensive gas chromatography coupled with mass spectrometry detection (GC×GC-MS) and data processing using advanced fingerprinting approaches. Experiments were carried out on roasted hazelnuts and on Gianduja pastes (sugar, vegetable oil, hazelnuts, cocoa, nonfat dried milk, vanilla flavorings) and demonstrated that the information potential of each analysis can better be exploited if suitable quantitation methods are applied. Quantitation approaches through Multiple Headspace Extraction and Standard Addition were compared in terms of performance parameters (linearity, precision, accuracy, Limit of Detection and Limit of Quantitation) under headspace linearity conditions. The results on 19 key analytes, potent odorants, and technological markers, and more than 300 fingerprint components, were used for further processing to obtain information concerning the effect of the matrix on volatile release, and to produce an informative chemical blueprint for use in sensomics and flavoromics. The importance of quantitation approaches in headspace analysis of solid matrices of complex composition, and the advantages of MHE, are also critically discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Quality improvements of cell membrane chromatographic column.

    Science.gov (United States)

    Ding, Xuan; Chen, Xiaofei; Cao, Yan; Jia, Dan; Wang, Dongyao; Zhu, Zhenyu; Zhang, Juping; Hong, Zhanying; Chai, Yifeng

    2014-09-12

    Cell Membrane Chromatography (CMC) is a biological affinity chromatographic method using a silica stationary phase covered with specific cell membrane. However, its short life span and poor quality control was highlighted in a lot of research articles. In this study, special attention has been paid to the disruption, cell load and packing procedure in order to improve the quality of the CMC columns. Hereto, two newly established CMC models, HSC-T6/CMC and SMMC-7721/CMC have been developed and used in this research project. The optimization of the abovementioned parameters resulted in a better reproducibility of the retention time of the compound GFT (RSDCMC columns. 3.5×10(7)cells were the optimal cell load for the preparation of the CMC columns, the disruption condition was optimized to 5 cycles (400W and 20s interval per cycle) by an ultrasonic processor reducing the total time of cell disruption to 1.5min and the packing flow rate was optimized by applying a linear gradient program. Additionally, 4% paraformaldehyde (PFA) was employed to improve the column quality and prolong the column life span. The results showed that the retention time was longer with PFA treated columns than the ones obtained with the control groups. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Chromatographic Techniques for Rare Earth Elements Analysis

    Science.gov (United States)

    Chen, Beibei; He, Man; Zhang, Huashan; Jiang, Zucheng; Hu, Bin

    2017-04-01

    The present capability of rare earth element (REE) analysis has been achieved by the development of two instrumental techniques. The efficiency of spectroscopic methods was extraordinarily improved for the detection and determination of REE traces in various materials. On the other hand, the determination of REEs very often depends on the preconcentration and separation of REEs, and chromatographic techniques are very powerful tools for the separation of REEs. By coupling with sensitive detectors, many ambitious analytical tasks can be fulfilled. Liquid chromatography is the most widely used technique. Different combinations of stationary phases and mobile phases could be used in ion exchange chromatography, ion chromatography, ion-pair reverse-phase chromatography and some other techniques. The application of gas chromatography is limited because only volatile compounds of REEs can be separated. Thin-layer and paper chromatography are techniques that cannot be directly coupled with suitable detectors, which limit their applications. For special demands, separations can be performed by capillary electrophoresis, which has very high separation efficiency.

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