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Sample records for chromatography high pressure liquid

  1. 21 CFR 862.2260 - High pressure liquid chromatography system for clinical use.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false High pressure liquid chromatography system for... Clinical Laboratory Instruments § 862.2260 High pressure liquid chromatography system for clinical use. (a) Identification. A high pressure liquid chromatography system for clinical use is a device intended to...

  2. Isolation of Xanthomegnin from Penicillium viridicatum by Preparative High-Pressure Liquid Chromatography

    OpenAIRE

    Peterson, R E; Grove, M D

    1983-01-01

    A method was developed for the production and purification of xanthomegnin from Penicillium viridicatum (NRRL 6430) cultured on rice at 15°C for 29 days. Liquid-liquid extraction followed by high-pressure liquid chromatography afforded 440 mg of crystalline xanthomegnin per kg of rice.

  3. Muramic Acid Measurements for Bacterial Investigations in Marine Environments by High-Pressure Liquid Chromatography

    OpenAIRE

    Mimura, Toru; Romano, Jean-Claude

    1985-01-01

    Muramic acid, a constituent of procaryotic cell walls, was assayed by high-pressure liquid chromatography in samples from several marine environments (water column, surface microlayer, and sediment) and a bacterial culture. It is used as a microbial biomass indicator. The method gave a good separation of muramic acid from interfering compounds with satisfactory reproducibility. A pseudomonad culture had a muramic acid content of 4.7 × 10−10 to 5.3 × 10−10 μg per cell during growth. In natural...

  4. Muramic Acid Measurements for Bacterial Investigations in Marine Environments by High-Pressure Liquid Chromatography

    Science.gov (United States)

    Mimura, Toru; Romano, Jean-Claude

    1985-01-01

    Muramic acid, a constituent of procaryotic cell walls, was assayed by high-pressure liquid chromatography in samples from several marine environments (water column, surface microlayer, and sediment) and a bacterial culture. It is used as a microbial biomass indicator. The method gave a good separation of muramic acid from interfering compounds with satisfactory reproducibility. A pseudomonad culture had a muramic acid content of 4.7 × 10−10 to 5.3 × 10−10 μg per cell during growth. In natural water samples, highly significant relationships were found between muramic acid concentrations and bacterial numbers for populations of 108 to 1011 cells per liter. The muramic acid content in natural marine water decreased from 5.3 × 10−10 to 1.6 × 10−10 μg per cell with increasing depth. In coastal sediments exposed to sewage pollution, concentrations of muramic acid, ATP, organic carbon, and total amino acids displayed a parallel decrease with increasing distance from the sewage outlet. Advantages of muramic acid measurement by high-pressure liquid chromatography are its high sensitivity and reduction of preparation steps, allowing a short time analysis. PMID:16346848

  5. Adaptation of a High-Pressure Liquid Chromatography System for the Measurement of Viscosity

    Directory of Open Access Journals (Sweden)

    Sonia Gregory

    2014-03-01

    Full Text Available The state-of-the-art instruments for the determination of viscosity of liquids typically require a significant amount of sample, and have relatively low throughput due to manual and sequential measurements. In this study, it was demonstrated that the pressure generated by the flow of viscous fluids through a capillary could be precisely measured employing high-pressure liquid chromatography systems (HPLC using glycerol solutions of moderate viscosity as a mobile phase, and correlated to the dynamic (absolute viscosity. The parameters allowing calculation of the viscosity of glycerol calibration standards as a function of temperature were established. The measurements were made with volumes as small as 10 μL, and the use of an autosampler permitted unattended analysis of a large number samples. The method appears to be particularly well suited for the development of viscous formulations of therapeutic, protein-based macromolecules, where the amount sample is typically limited and relatively wide ranges of conditions are considered in the optimization process. The utility of the methods was illustrated by application to the development of concentrated inactivated virus vaccines.

  6. Determination of boron in nuclear materials at subppm levels by high pressure liquid chromatography (HPLC)

    International Nuclear Information System (INIS)

    Experiments were conducted for the determination of boron in U3O8 powder, aluminium metal and milliQ water using dynamically modified Reversed Phase High Pressure Liquid Chromatography (RP-HPLC) and using two precolumn chromogenic agents viz. chromotropic acid and curcumin for complexing boron. The complex was separated from the excess of reagent and determined by HPLC. When present in subppm levels, chromotropic acid was used successfully only for determination boron in water samples. For determination of boron at subppm levels in uranium and aluminium samples, curcumin was used as the precolumn chromogenic agent. The boron curcumin complex (rosocyanin) was formed after extraction of boron with 2-ethyl-l, 3-hexane diol (EHD). The rosocyanin complex was then separated from excess curcumin by displacement chromatography. Linear calibration curves for boron amounts in the range of 0.02 μg to 0.5 μg were developed with correlation coefficients varying from 0.997 to 0.999 and were used for the determination of boron in aluminium and uranium samples. Precision of about 10% was achieved in samples containing less than 1 ppmw of boron. Detection limit of this method is 0.01 μg boron. (author)

  7. Rapid method for determination of kanamycin and dibekacin in serum by use of high-pressure liquid chromatography.

    OpenAIRE

    Kubo, H.; Kobayashi, Y.; T. Nishikawa

    1985-01-01

    A rapid, simple, and accurate method for the determination of kanamycin and dibekacin in serum by use of high-pressure liquid chromatography is described. The serum proteins were precipitated with 3.5% perchloric acid containing sodium octanesulfonate. After centrifugation, a sample of the supernatant was directly injected into the chromatograph. The determination of kanamycin and dibekacin was performed by a combination of reverse-phase, ion-pair chromatography, postcolumn derivatization wit...

  8. Assessment of radiochemical purity of [{sup 18}F]fludeoxyglucose by high pressure liquid chromatography (HPLC)

    Energy Technology Data Exchange (ETDEWEB)

    Lacerda, Aline E.; Silva, Juliana B.; Silveira, Marina B.; Ferreira, Soraya Z., E-mail: radiofarmacoscdtn@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Unidade de Pesquisa e Producao de Radiofarmacos

    2011-07-01

    The quality control of [{sup 18}F]fludeoxyglucose ({sup 18}FDG) has received attention due to its increasing clinical use. Although the quality requirements of {sup 18}FDG are established in various pharmacopoeia, the suitability of all testing methods used should be verified under actual conditions of use and documented. The aim of this study was to develop a high pressure liquid chromatography (HPLC) method for radiochemical purity evaluation of {sup 18}FDG, based on pharmacopoeia references, and to verify its suitability for routine quality control in our centre. HPLC analysis was performed with an Agilent HPLC. {sup 18}FDG and impurities were separated on an anion-exchange column by isocratic elution with 0.1 M NaOH as the mobile phase. Detection was accomplished with refractive index and NaI (Tl) scintillation detectors. The flow rate of the mobile phase was set at 0.8 mL/min and the column temperature was kept at 35 deg C. Specificity, linearity, precision and robustness were assessed to verify if the method was adequate for its intended purpose. Retention time of {sup 18}FDG was not affected by the presence of other components of the formulation and a good peak resolution was achieved. The analytical curve of {sup 18}FDG was linear, with a correlation coefficient value of 0.9995. Intraday repeatable precision, reported as the relative standard deviation, was 0.11%. Analytical procedure remained unaffected by small variations in mobile phase flow rate. Results evidenced that HPLC is suitable for radiochemical purity evaluation of {sup 18}FDG, considering operational conditions of our laboratory. (author)

  9. High-Pressure Liquid Chromatography of Irradiated Nuclear Fue - Separation of Neodymium for Burn-up Determination

    DEFF Research Database (Denmark)

    Larsen, N. R.

    1979-01-01

    Neodymium is separated from solutions of spent nuclear fuel by high-pressure liquid chromatography in methanol-nitric acid-water media using an anion-exchange column. Chromatograms obtained by monitoring at 280 nm, illustrate the difficulties especially with the fission product ruthenium in nuclear...... chemistry. Preseparation of the rare earths and trivalent actinides using a di(2-ethylhexyl)phosphoric acid/kieselguhr column is described....

  10. Ergot alkaloids in rye flour determined by solid phase cation-exchange and high pressure liquid chromatography with fluorescence detection

    OpenAIRE

    Storm, Ida Drejer; Have Rasmussen, Peter; Strobel, Bjarne W.; Hansen, Hans Christian Bruun

    2008-01-01

    Abstract Ergot alkaloids (EAs) are mycotoxins which are unavoidable contaminants of cereal products, particularly rye. A method was compiled employing clean-up by cation-exchange solid phase extraction, separation by high-pressure liquid chromatography under alkaline conditions and fluorescence detection. It is capable of separating and quantifying both C8-isomers of ergocornine, a-ergocryptine, ergocristine, ergonovine, and ergotamine. The average recovery was 61?10 % with limits ...

  11. Analysis of ochratoxin A in pig tissues using high pressure liquid chromatography (HPLC) and liquid chromatography tandem mass spectrometry (LC/MS/MS) as confirmative methods

    OpenAIRE

    Milićević Dragan R.; Jurić Verica B.; Stefanović Srđan M.; Vesković-Moračanin Slavica M.; Janković Saša I.

    2009-01-01

    Two different analytical methods for the determination and confirmation of ochratoxin A (OTA) in blood serum, kidney and liver of pigs have been compared. Sample clean-up was based on liquid-liquid phase extraction. The detection of OTA was accomplished with high-performance liquid chromatography (HPLC) combined either with fluorescence detection (FL) or electro spray ionization (ESI+) tandem mass spectrometry (MS-MS). Comparative method evaluation was based on the investigation of 82 samples...

  12. Home-made online hyphenation of pressurized liquid extraction, turbulent flow chromatography, and high performance liquid chromatography, Cistanche deserticola as a case study.

    Science.gov (United States)

    Song, Qingqing; Li, Jun; Liu, Xiao; Zhang, Yuan; Guo, Liping; Jiang, Yong; Song, Yuelin; Tu, Pengfei

    2016-03-18

    Incompatibility between the conventional pressurized liquid extraction (PLE) devices and high performance liquid chromatography (HPLC) extensively hinders direct and green chemical analysis of herbal materials. Herein, a facile PLE module was configured, and then it was online hyphenated with HPLC via a turbulent flow chromatography (TFC) column. Regarding PLE module, a long PEEK tube (0.13 × 1000 mm) was employed to generate desired pressure (approximately 13.0 MPa) when warm acidic water (70 °C) was delivered as extraction solvent at a high flow rate (2.5 mL/min), and a hollow guard column (3.0 × 4.0 mm) was implemented to hold crude materials. Effluent was collected from the outlet of PEEK tube, concentrated, and subjected onto HPLC coupled with hybrid ion trap-time of flight mass spectrometer to assess the extraction efficiency and also to profile the chemical composition of Cistanche deserticola (CD) that is honored as "Ginseng of the desert". Afterwards, a TFC column was introduced to accomplish online transmission of low molecule weight components from PLE module to HPLC coupled with diode array detection, and two electronic 6-port/2-channel valves were in charge of alternating the whole system between extraction (0-3.0 min) and elution (3.0-35.0 min) phases. Quantitative method was developed and validated for simultaneous determination of eight primary phenylethanoid glycosides in CD using online PLE-TFC-HPLC. All findings demonstrated that the home-made platform is advantageous at direct chemical analysis, as well as time-, solvent-, and material-savings, suggesting a robust tool for chemical fingerprinting of herbs.

  13. Quantification of antidepressants and antipsychotics in human serum by precipitation and ultra high pressure liquid chromatography-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Hasselstrøm, Jørgen Bo

    2011-01-01

    precipitated with zinc sulphate and methanol containing a stable isotope labelled analog for each analyte. Quantitative analysis was performed by ultra high pressure liquid chromatography combined with a tandem mass spectrometer using a Zorbax SB-C8 column (2.0×50mm; 1.8m) with a mobile phase consisting of 0.......1% formic acid in water and methanol, respectively. The total run time of the chromatography was 4 min. Precision and trueness varied from 2.6% to 14.9% and 87.6% to 103.5%, respectively. At the lower limit of quantification, precision was up to 17.9% and trueness varied from 89.5% to 111.5%. A five point...

  14. Fast and comprehensive analysis of secondary metabolites in cocoa products using ultra high-performance liquid chromatography directly after pressurized liquid extraction.

    Science.gov (United States)

    Damm, Irina; Enger, Eileen; Chrubasik-Hausmann, Sigrun; Schieber, Andreas; Zimmermann, Benno F

    2016-08-01

    Fast methods for the extraction and analysis of various secondary metabolites from cocoa products were developed and optimized regarding speed and separation efficiency. Extraction by pressurized liquid extraction is automated and the extracts are analyzed by rapid reversed-phase ultra high-performance liquid chromatography and normal-phase high-performance liquid chromatography methods. After extraction, no further sample treatment is required before chromatographic analysis. The analytes comprise monomeric and oligomeric flavanols, flavonols, methylxanthins, N-phenylpropenoyl amino acids, and phenolic acids. Polyphenols and N-phenylpropenoyl amino acids are separated in a single run of 33 min, procyanidins are analyzed by normal-phase high-performance liquid chromatography within 16 min, and methylxanthins require only 6 min total run time. A fourth method is suitable for phenolic acids, but only protocatechuic acid was found in relevant quantities. The optimized methods were validated and applied to 27 dark chocolates, one milk chocolate, two cocoa powders and two food supplements based on cocoa extract.

  15. Fast and comprehensive analysis of secondary metabolites in cocoa products using ultra high-performance liquid chromatography directly after pressurized liquid extraction.

    Science.gov (United States)

    Damm, Irina; Enger, Eileen; Chrubasik-Hausmann, Sigrun; Schieber, Andreas; Zimmermann, Benno F

    2016-08-01

    Fast methods for the extraction and analysis of various secondary metabolites from cocoa products were developed and optimized regarding speed and separation efficiency. Extraction by pressurized liquid extraction is automated and the extracts are analyzed by rapid reversed-phase ultra high-performance liquid chromatography and normal-phase high-performance liquid chromatography methods. After extraction, no further sample treatment is required before chromatographic analysis. The analytes comprise monomeric and oligomeric flavanols, flavonols, methylxanthins, N-phenylpropenoyl amino acids, and phenolic acids. Polyphenols and N-phenylpropenoyl amino acids are separated in a single run of 33 min, procyanidins are analyzed by normal-phase high-performance liquid chromatography within 16 min, and methylxanthins require only 6 min total run time. A fourth method is suitable for phenolic acids, but only protocatechuic acid was found in relevant quantities. The optimized methods were validated and applied to 27 dark chocolates, one milk chocolate, two cocoa powders and two food supplements based on cocoa extract. PMID:27418182

  16. Comparative analysis of different plant oils by high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry.

    Science.gov (United States)

    Jakab, Annamaria; Héberger, Károly; Forgács, Esther

    2002-11-01

    Different vegetable oil samples (almond, avocado, corngerm, grapeseed, linseed, olive, peanut, pumpkin seed, soybean, sunflower, walnut, wheatgerm) were analyzed using high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry. A gradient elution technique was applied using acetone-acetonitrile eluent systems on an ODS column (Purospher, RP-18e, 125 x 4 mm, 5 microm). Identification of triacylglycerols (TAGs) was based on the pseudomolecular ion [M+1]+ and the diacylglycerol fragments. The positional isomers of triacylglycerol were identified from the relative intensities of the [M-RCO2]+ fragments. Linear discriminant analysis (LDA) as a common multivariate mathematical-statistical calculation was successfully used to distinguish the oils based on their TAG composition. LDA showed that 97.6% of the samples were classified correctly.

  17. Comparative analysis of different plant oils by high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry.

    Science.gov (United States)

    Jakab, Annamaria; Héberger, Károly; Forgács, Esther

    2002-11-01

    Different vegetable oil samples (almond, avocado, corngerm, grapeseed, linseed, olive, peanut, pumpkin seed, soybean, sunflower, walnut, wheatgerm) were analyzed using high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry. A gradient elution technique was applied using acetone-acetonitrile eluent systems on an ODS column (Purospher, RP-18e, 125 x 4 mm, 5 microm). Identification of triacylglycerols (TAGs) was based on the pseudomolecular ion [M+1]+ and the diacylglycerol fragments. The positional isomers of triacylglycerol were identified from the relative intensities of the [M-RCO2]+ fragments. Linear discriminant analysis (LDA) as a common multivariate mathematical-statistical calculation was successfully used to distinguish the oils based on their TAG composition. LDA showed that 97.6% of the samples were classified correctly. PMID:12462617

  18. Panax ginseng Adventitious Root Suspension Culture: Protocol for Biomass Production and Analysis of Ginsenosides by High Pressure Liquid Chromatography.

    Science.gov (United States)

    Murthy, Hosakatte Niranjana; Paek, Kee Yoeup

    2016-01-01

    Panax ginseng C.A. Meyer (Korean ginseng) is a popular herbal medicine. It has been used in Chinese and Oriental medicines since thousands of years. Ginseng products are generally used as a tonic and an adaptogen to resist the adverse influence of a wide range of physical, chemical and biological factors, and to restore homeostasis. Ginsenosides or ginseng saponins are the principal active ingredients of ginseng. Since ginseng cultivation process is very slow and needs specific environment for field cultivation, cell and tissue cultures are sought as alternatives for the production of ginseng biomass and bioactive compounds. In this chapter, we focus on methods of induction of adventitious roots from ginseng roots, establishment of adventitious root suspension cultures using bioreactors, procedures for processing of adventitious roots, and analysis of ginsenosides by high pressure liquid chromatography. PMID:27108314

  19. Determination of the rodenticide difenacoum in biological materials by high-pressure liquid chromatography with confirmation of identity by mass spectrometry.

    Science.gov (United States)

    Mundy, D E; Machin, A F

    1977-09-21

    A method for determining difenacoum in liver, plasma, urine and feedingstuffs by high-pressure liquid chromatography is described. Samples are cleaned up by molecular exclusion chromatography on porous glass. In some cases this also serves for determination; if not, the separated difenacoum is determined on an adsorption column. Identity is confirmed by chemical ionisation mass spectrometry. Recoveries at levels of 0.025-5 ppm from plasma were 101-113% by exclusion chromatography alone and 93-101% after adsorption chromatography. Recoveries from liver after both chromatographic steps were 62-86%. Reasons for the lower recoveries from liver are suggested. PMID:893620

  20. High-Pressure Open-Channel On-Chip Electroosmotic Pump for Nanoflow High Performance Liquid Chromatography

    OpenAIRE

    Wang, Wei; Gu, Congying; Lynch, Kyle B.; Lu, Joann J.; Zhang, Zhengyu; Pu, Qiaosheng; Liu, Shaorong

    2014-01-01

    Here, we construct an open-channel on-chip electroosmotic pump capable of generating pressures up to ∼170 bar and flow rates up to ∼500 nL/min, adequate for high performance liquid chromatographic (HPLC) separations. A great feature of this pump is that a number of its basic pump units can be connected in series to enhance its pumping power; the output pressure is directly proportional to the number of pump units connected. This additive nature is excellent and useful, and no other pumps can ...

  1. Development of a method for quantitation of retinol and retinyl palmitate in human serum using high-performance liquid chromatography atmospheric pressure chemical ionization mass spectrometry.

    NARCIS (Netherlands)

    Breemen, van R.B.; Nikolic, D.; Xu, X.Y.; Xiong, Y.S.; Lieshout, van M.; West, C.E.; Schilling, A.B.

    1998-01-01

    A method for the quantitative analysis of the vitamin A compounds all-trans-retinol and all-trans-retinyl palmitate was developed using high-performance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (APCI-LC-MS). Unlike previous quantitative mass spectrometric meth

  2. Intrinsic advantages of packed capillaries over narrow-bore columns in very high-pressure gradient liquid chromatography.

    Science.gov (United States)

    Gritti, Fabrice; McDonald, Thomas; Gilar, Martin

    2016-06-17

    250μm×100mm fused silica glass capillaries were packed with 1.8μm high-strength silica (HSS) fully porous particles. They were prepared without bulky stainless steel endfittings and metal frits, which both generate significant sample dispersion. The isocratic efficiencies and gradient peak capacities of these prototype capillary columns were measured for small molecules (n-alkanophenones) using a home-made ultra-low dispersive micro-HPLC instrument. Their resolution power was compared to that of standard 2.1mm×100mm very high-pressure liquid chromatography (vHPLC) narrow-bore columns packed with the same particles. The results show that, for the same column efficiency (25000 plates) and gradient steepness (0.04min(-1)), the peak capacity of the 250μm i.d. capillary columns is systematically 15-20% higher than that of the 2.1mm i.d. narrow-bore columns. A validated model of gradient chromatography enabled one to predict accurately the observed peak capacities of the capillary columns for non-linear solvation strength retention behavior and under isothermal conditions. Thermodynamics applied to the eluent quantified the temperature difference for the thermal gradients in both capillary and narrow-bore columns. Experimental data revealed that the gradient peak capacity is more affected by viscous heating than the column efficiency. Unlike across 2.1mm i.d. columns, the changes in eluent composition across the 250μm i.d. columns during the gradient is rapidly relaxed by transverse dispersion. The combination of (1) the absence of viscous heating and (2) the high uniformity of the eluent composition across the diameter of capillary columns explains the intrinsic advantage of capillary over narrow-bore columns in gradient vHPLC.

  3. Analysis of wax ester molecular species by high performance liquid chromatography/atmospheric pressure chemical ionisation mass spectrometry.

    Science.gov (United States)

    Vrkoslav, Vladimír; Urbanová, Klára; Cvacka, Josef

    2010-06-18

    High chromatographic resolution of wax esters (WEs) was achieved by non-aqueous reversed-phase liquid chromatography on a Nova-Pak C18 column by optimising the acetonitrile/ethyl acetate mobile phase gradient. The retention behaviour of WEs was studied in this chromatographic system. The WEs eluted according to their equivalent carbon number (ECN) values; within the group of WEs with the identical ECN, the most unsaturated species tended to elute first. The isobaric WEs with different positions of the ester moiety were separated from each other whenever the lengths of the chains were sufficiently different. The methyl-branched esters eluted at shorter retention times than the straight-chained analogues, and the resolution among methyl-branched WEs depended on the position of the branching. The analytes were detected by atmospheric pressure chemical ionisation mass spectrometry (APCI-MS) using data-dependent scanning. WEs provided simple full-scan spectra with abundant protonated molecules and low-intensity fragments. Collision-induced dissociation (CID) promoted identification of the WE molecular species. The responses of WEs were found to be dependent on the number of double bonds and on the alkyl-chain length; the limits of the detection ranged from 20micromol/L to 200nmol/L. The HPLC/APCI-MS was applied for the analysis of the WEs isolated from honeycomb beeswax, jojoba oil and human hair. Good agreement between reported results and the literature data was achieved, with several novel polyunsaturated WEs also being found.

  4. Quasi-adiabatic vacuum-based column housing for very high-pressure liquid chromatography.

    Science.gov (United States)

    Gritti, Fabrice; Gilar, Martin; Jarrell, Joseph A

    2016-07-22

    A prototype vacuum-based (10(-6)Torr) column housing was built to thermally isolate the chromatographic column from the external air environment. The heat transfer mechanism is solely controlled by surface radiation, which was minimized by wrapping the column with low-emissivity aluminum tape. The adiabaticity of the column housing was quantitatively assessed from the measurement of the operational pressure and fluid temperature at the outlet of a 2.1mm×100mm column (sub-2 μm particles). The pressure drop along the column was raised up to 1kbar. The enthalpy balance of the eluent (water, acetonitrile, and one water/acetonitrile mixture, 70/30, v/v) showed that less than 1% of the viscous heat generated by friction of the fluid against the packed bed was lost to the external air environment. Such a vacuum-based column oven minimizes the amplitude of the radial temperature gradients across the column diameter and maximizes its resolving power.

  5. Quasi-adiabatic vacuum-based column housing for very high-pressure liquid chromatography.

    Science.gov (United States)

    Gritti, Fabrice; Gilar, Martin; Jarrell, Joseph A

    2016-07-22

    A prototype vacuum-based (10(-6)Torr) column housing was built to thermally isolate the chromatographic column from the external air environment. The heat transfer mechanism is solely controlled by surface radiation, which was minimized by wrapping the column with low-emissivity aluminum tape. The adiabaticity of the column housing was quantitatively assessed from the measurement of the operational pressure and fluid temperature at the outlet of a 2.1mm×100mm column (sub-2 μm particles). The pressure drop along the column was raised up to 1kbar. The enthalpy balance of the eluent (water, acetonitrile, and one water/acetonitrile mixture, 70/30, v/v) showed that less than 1% of the viscous heat generated by friction of the fluid against the packed bed was lost to the external air environment. Such a vacuum-based column oven minimizes the amplitude of the radial temperature gradients across the column diameter and maximizes its resolving power. PMID:27324623

  6. High-performance liquid chromatography of biopolymers

    Energy Technology Data Exchange (ETDEWEB)

    Regnier, F.E.

    1983-10-21

    The ability to separate biological macromolecules with good resolution on liquid chromatographic columns has depended on the development of suitable packing materials. In size exclusion chromatography, molecules are separated by size on the basis of differential permeation of the packing. Ion exchange, hydrophobic interaction (or reversed-phase), and affinity chromatography are all surface-mediated separation methods, although they depend on different retention mechanisms. High-performance liquid chromatographic columns designed for biopolymers offer major advantages over conventional columns in both speed and resolving power. The exponential growth of literature on the high-performance separation of peptides and proteins in particular indicates that the techniques will become the dominant form of column liquid chromatography. 92 refs., 4 figs.

  7. Determination of potato glycoalkaloids using high-pressure liquid chromatography-electrospray ionisation/mass spectrometry.

    Science.gov (United States)

    Matsuda, Fumio; Morino, Keiko; Miyazawa, Haruna; Miyashita, Masahiro; Miyagawa, Hisashi

    2004-01-01

    A method for quantifying two toxic glycoalkaloids, alpha-solanine and alpha-chaconine, in potato (Solanum tuberosum) tuber tissue was developed using HPLC-electrospray ionisation (ESI)/MS. Potato samples were extracted with 5% aqueous acetic acid, and the extracts were subjected directly to HPLC-ESI/MS after filtration. By determining the intensities of the protonated molecules of alpha-solanine (m/z 868) and alpha-chaconine (m/z 852) using selected ion monitoring (positive ion mode), a sensitive assay was attained with detection limits of 38 and 14 ppb for the two glycoalkaloids, respectively. The high sensitivity and selectivity of MS detection effectively reduced the time of analysis thus enabling a high throughput assay of glycoalkaloids in potato tubers.

  8. Determination of glucosinolates in 19 Chinese medicinal plants with spectrophotometry and high-pressure liquid chromatography.

    Science.gov (United States)

    Hu, Ye; Liang, Hao; Yuan, Qipeng; Hong, Yuancheng

    2010-08-01

    Glucosinolates were evaluated in 19 traditional Chinese medicinal plants involved in seven different families: Brassicaceae, Capparaceae, Euphorbiaceae, Phytolaccaceae, Tropaeolaceae, Caricaceae and Rubiaceae. The total glucosinolate contents were determined by spectrophotometry. Results showed that the high contents of total glucosinolates were found in some herbs of Brassicaceae, Capparaceae and Euphorbiaceae families, while low total glucosinolate contents were observed in two Rubiaceae herbs. In addition, eight glucosinolates (glucoraphanin, glucoraphenin, sinalbin, sinigrin, progoitrin, 4-hydroglucobrassicin, glucoiberin and glucoibervirin) in these herbs were measured using HPLC, and the data showed that individual glucosinolates and their contents varied at different degrees among the distinct species. The highest contents of cancer-protective compounds were found in the seeds of Raphanus sativus L. (glucoraphenin), Sinapis alba (sinalbin) and Phyllanthus emblica L. (sinigrin). PMID:20645206

  9. Development of a high performance liquid chromatography method and a liquid chromatography-tandem mass spectrometry method with pressurized liquid extraction for simultaneous quantification and confirmation of cyromazine, melamine and its metabolites in foods of animal origin

    Energy Technology Data Exchange (ETDEWEB)

    Yu Huan; Tao Yanfei; Chen Dongmei; Wang Yulian; Liu Zhaoying; Pan Yuanhu; Huang Lingli; Peng Dapeng; Dai Menghong; Liu Zhenli [MOA Key Laboratory of Food Safety Evaluation/National Reference Laboratory of Veterinary Drug Residues (HZAU), Huazhong Agricultural University, Wuhan, Hubei 430070 (China); Yuan Zonghui, E-mail: yuan5802@mail.hzau.edu.cn [MOA Key Laboratory of Food Safety Evaluation/National Reference Laboratory of Veterinary Drug Residues (HZAU), Huazhong Agricultural University, Wuhan, Hubei 430070 (China)

    2010-12-03

    Simple and sensitive methods have been developed for simultaneous detection of cyromazine, melamine and their metabolites (ammeline, ammelide and cyanuric acid) in samples of animal origins. These include a high performance liquid chromatography (HPLC) method and a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method and are useful in regular monitoring and in toxicity studies of these molecules. Representative samples used in this study include muscles and livers of swine, bovine, sheep and chicken, kidneys of swine, bovine and sheep, and milk powder. A new sample preparation procedure with pressurized liquid extraction (PLE) at 1400 psi and 70 deg. C was investigated. Quantification of these five compounds by HPLC was achieved using an APS-2 column with UV detection at 230 nm. Limit of detection (LOD) was at 10 {mu}g kg{sup -1}, and limit of quantification (LOQ) was at 40 {mu}g kg{sup -1}. Recoveries of the five analytes in spiked samples ranged from 72.2% to 115.4% with RSD less than 12%. Confirmatory analysis of the analytes was performed using LC-MS/MS in selected reaction monitoring (SRM) mode. The LOD and LOQ were 5 {mu}g kg{sup -1} and 15 {mu}g kg{sup -1}, respectively. This is the first simultaneous analysis of cyromazine, melamine, ammeline, ammelide and cyanuric acid residues in complex tissue samples using PLE and HPLC. It is expected that these methods will find many practical applications in evaluating the safety of cyromazine, melamine and their metabolites.

  10. Implementation of high slurry concentration and sonication to pack high-efficiency, meter-long capillary ultrahigh pressure liquid chromatography columns.

    Science.gov (United States)

    Godinho, Justin M; Reising, Arved E; Tallarek, Ulrich; Jorgenson, James W

    2016-09-01

    Slurry packing capillary columns for ultrahigh pressure liquid chromatography is complicated by many interdependent experimental variables. Previous results have suggested that combination of high slurry concentration and sonication during packing would create homogeneous bed microstructures and yield highly efficient capillary columns. Herein, the effect of sonication while packing very high slurry concentrations is presented. A series of six, 1m×75μm internal diameter columns were packed with 200mg/mL slurries of 2.02μm bridged-ethyl hybrid silica particles. Three of the columns underwent sonication during packing and yielded highly efficient separations with reduced plate heights as low as 1.05. PMID:27499108

  11. High perfomance liquid chromatography in pharmaceutical analyses.

    Science.gov (United States)

    Nikolin, Branko; Imamović, Belma; Medanhodzić-Vuk, Saira; Sober, Miroslav

    2004-05-01

    In testing the pre-sale procedure the marketing of drugs and their control in the last ten years, high performance liquid chromatography replaced numerous spectroscopic methods and gas chromatography in the quantitative and qualitative analysis. In the first period of HPLC application it was thought that it would become a complementary method of gas chromatography, however, today it has nearly completely replaced gas chromatography in pharmaceutical analysis. The application of the liquid mobile phase with the possibility of transformation of mobilized polarity during chromatography and all other modifications of mobile phase depending upon the characteristics of substance which are being tested, is a great advantage in the process of separation in comparison to other methods. The greater choice of stationary phase is the next factor which enables realization of good separation. The separation line is connected to specific and sensitive detector systems, spectrafluorimeter, diode detector, electrochemical detector as other hyphernated systems HPLC-MS and HPLC-NMR, are the basic elements on which is based such wide and effective application of the HPLC method. The purpose high performance liquid chromatography (HPLC) analysis of any drugs is to confirm the identity of a drug and provide quantitative results and also to monitor the progress of the therapy of a disease.1) Measuring presented on the Fig. 1. is chromatogram obtained for the plasma of depressed patients 12 h before oral administration of dexamethasone. It may also be used to further our understanding of the normal and disease process in the human body trough biomedical and therapeutically research during investigation before of the drugs registration. The analyses of drugs and metabolites in biological fluids, particularly plasma, serum or urine is one of the most demanding but one of the most common uses of high performance of liquid chromatography. Blood, plasma or serum contains numerous endogenous

  12. Determination of Essential Fatty Acid Composition among Mutant Lines of Canola (Brassica napus), through High Pressure Liquid Chromatography

    Institute of Scientific and Technical Information of China (English)

    Ghulam Raza; Aquil Siddique; Imtiaz Ahmad Khan; Muhammed Yasin Ashraf; Abdullah Khatri

    2009-01-01

    The present study aimed to quantify the methyl esters of lenoleic acid (LA), γ-lenolenic acid (LNA) and oleic acid (OL) in the oil of Brassica napus mutants. Five stable mutants (ROO-75/1, ROO-100/6, ROO-125/12, ROO-125/14, and ROO-125/17)of B. napus cv. 'Rainbow' (P) and three mutants (W97-95116, W97-0.75/11 and W97-.075/13) of B. napus cv. 'Westar' (P) at M6 stage, exhibiting better yield and yield components, were analyzed for essential fatty acids. The highest seed yield was observed in the mutant (ROO-100/6) followed by ROO-125/14 of Rainbow, that is, 34% and 32% higher than their parent plants, respectively. Westar mutant W97-75/11 also showed 30% higher seed yield than its parent plant. High performance liquid chromatography analysis of the composition of fatty acids indicated that OL was the most dominant fatty acid, ranging from 39.1 to 66.3%; LA was second (15.3-41.6%) and LNA was third (18.1-28.9%). Mutant ROO-125/14 showed higher OL contents than parent (Rainbow). These results are expected to support the approval of ROO-125/14 in the National Uniform Varietal Yield Trials (NUVYT) as a new variety based on high oil quality.

  13. The use of ultra-high pressure liquid chromatography with tandem mass spectrometric detection in the analysis of agrochemical residues and mycotoxins in food - challenges and applications.

    Science.gov (United States)

    O'Mahony, John; Clarke, Lesa; Whelan, Michelle; O'Kennedy, Richard; Lehotay, Steven J; Danaher, Martin

    2013-05-31

    In the field of food contaminant analysis, the most significant development of recent years has been the integration of ultra-high pressure liquid chromatography (UHPLC), coupled to tandem quadrupole mass spectrometry (MS/MS), into analytical applications. In this review, we describe the emergence of UHPLC through technological advances. The implications of this new chromatographic technology for MS detection are discussed, as well as some of the remaining challenges in exploiting it for chemical residue applications. Finally, a comprehensive overview of published applications of UHPLC-MS in food contaminant analysis is presented, with a particular focus on veterinary drug residues.

  14. The use of ultra-high pressure liquid chromatography with tandem mass spectrometric detection in the analysis of agrochemical residues and mycotoxins in food - challenges and applications.

    Science.gov (United States)

    O'Mahony, John; Clarke, Lesa; Whelan, Michelle; O'Kennedy, Richard; Lehotay, Steven J; Danaher, Martin

    2013-05-31

    In the field of food contaminant analysis, the most significant development of recent years has been the integration of ultra-high pressure liquid chromatography (UHPLC), coupled to tandem quadrupole mass spectrometry (MS/MS), into analytical applications. In this review, we describe the emergence of UHPLC through technological advances. The implications of this new chromatographic technology for MS detection are discussed, as well as some of the remaining challenges in exploiting it for chemical residue applications. Finally, a comprehensive overview of published applications of UHPLC-MS in food contaminant analysis is presented, with a particular focus on veterinary drug residues. PMID:23352828

  15. Multicomponent mixed dopant optimization for rapid screening of polycyclic aromatic hydrocarbons using ultra high performance liquid chromatography coupled to atmospheric pressure photoionization high-resolution mass spectrometry

    KAUST Repository

    Sioud, Salim

    2012-05-04

    RATIONALE To enhance the ionization efficiencies in atmospheric pressure photoionization mass spectrometry a dopant with favorable ionization energy such as chlorobenzene is typically used. These dopants are typically toxic and difficult to mix with water-soluble organic solvents. In order to achieve a more efficient and less toxic dopant, a multicomponent mixed dopant was explored. METHODS A multicomponent mixed dopant for non-targeted rapid screening of polycyclic aromatic hydrocarbons (PAHs) was developed and optimized using ultra high performance liquid chromatography (UPLC) coupled to atmospheric pressure photoionization high-resolution mass spectrometry. Various single and multicomponent mixed dopants consisting of ethanol, chlorobenzene, bromobenzene, anisole and toluene were evaluated. RESULTS Fourteen out of eighteen PAHs were successfully separated and detected at low pg/μL levels within 5 min with high mass accuracy ≤4 ppm. The optimal mixed multicomponent dopant consisted of ethanol/chlorobenzene/bromobenzene/anisole (98.975:0.1:0.9:0.025, v/v %) and it improved the limit of detection (LOD) by 2- to 10-fold for the tested PAHs compared to those obtained with pure chlorobenzene. CONCLUSIONS A novel multicomponent dopant that contains 99% ethanol and 1% mixture of chlorobenzene, bromobenzene and anisole was found to be an effective dopant mixture to ionize PAHs. The developed UPLC multicomponent dopant assisted atmospheric pressure photoionization high-resolution mass spectrometry offered a rapid non targeted screening method for detecting the PAHs at low pg/;μL levels within a 5 min run time with high mass accuracy a;circ4 ppm. Copyright © 2012 John Wiley & Sons, Ltd.

  16. A fully automated method for simultaneous determination of aflatoxins and ochratoxin A in dried fruits by pressurized liquid extraction and online solid-phase extraction cleanup coupled to ultra-high-pressure liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Campone, Luca; Piccinelli, Anna Lisa; Celano, Rita; Russo, Mariateresa; Valdés, Alberto; Ibáñez, Clara; Rastrelli, Luca

    2015-04-01

    According to current demands and future perspectives in food safety, this study reports a fast and fully automated analytical method for the simultaneous analysis of the mycotoxins with high toxicity and wide spread, aflatoxins (AFs) and ochratoxin A (OTA) in dried fruits, a high-risk foodstuff. The method is based on pressurized liquid extraction (PLE), with aqueous methanol (30%) at 110 °C, of the slurried dried fruit and online solid-phase extraction (online SPE) cleanup of the PLE extracts with a C18 cartridge. The purified sample was directly analysed by ultra-high-pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) for sensitive and selective determination of AFs and OTA. The proposed analytical procedure was validated for different dried fruits (vine fruit, fig and apricot), providing method detection and quantification limits much lower than the AFs and OTA maximum levels imposed by EU regulation in dried fruit for direct human consumption. Also, recoveries (83-103%) and repeatability (RSD < 8, n = 3) meet the performance criteria required by EU regulation for the determination of the levels of mycotoxins in foodstuffs. The main advantage of the proposed method is full automation of the whole analytical procedure that reduces the time and cost of the analysis, sample manipulation and solvent consumption, enabling high-throughput analysis and highly accurate and precise results.

  17. Analysis of oxysterols and vitamin D metabolites in mouse brain and cell line samples by ultra-high-performance liquid chromatography-atmospheric pressure photoionization-mass spectrometry.

    Science.gov (United States)

    Ahonen, Linda; Maire, Florian B R; Savolainen, Mari; Kopra, Jaakko; Vreeken, Rob J; Hankemeier, Thomas; Myöhänen, Timo; Kylli, Petri; Kostiainen, Risto

    2014-10-17

    We have developed an ultra-high-performance liquid chromatography-atmospheric pressure photoionization-tandem mass spectrometric (UHPLC-APPI-MS/MS) method for the simultaneous quantitative analyses of several oxysterols and vitamin D metabolites in mouse brain and cell line samples. An UHPLC-APPI-high resolution mass spectrometric (UHPLC-APPI-HRMS) method that uses a quadrupole-time of flight mass spectrometer was also developed for confirmatory analysis and for the identification of non-targeted oxysterols. Both methods showed good quantitative performance. Furthermore, APPI provides high ionization efficiency for determining oxysterols and vitamin D related compounds without the time consuming derivatization step needed in the conventionally used electrospray ionization method to achieve acceptable sensitivity. Several oxysterols were quantified in mouse brain and cell line samples. Additionally, 25-hydroxyvitamin D3 was detected in mouse brain samples for the first time.

  18. Screening of lake sediments for emerging contaminants by liquid chromatography atmospheric pressure photoionization and electrospray ionization coupled to high resolution mass spectrometry.

    Science.gov (United States)

    Chiaia-Hernandez, Aurea C; Krauss, Martin; Hollender, Juliane

    2013-01-15

    We developed a multiresidue method for the target and suspect screening of more than 180 pharmaceuticals, personal care products, pesticides, biocides, additives, corrosion inhibitors, musk fragrances, UV light stabilizers, and industrial chemicals in sediments. Sediment samples were freeze-dried, extracted by pressurized liquid extraction, and cleaned up by liquid-liquid partitioning. The quantification and identification of target compounds with a broad range of physicochemical properties (log K(ow) 0-12) was carried out by liquid chromatography followed by electrospray ionization (ESI) and atmospheric pressure photoionization (APPI) coupled to high resolution Orbitrap mass spectrometry (HRMS/MS). The overall method average recoveries and precision are 103% and 9% (RSD), respectively. The method detection limits range from 0.010 to 4 ng/g(dw), while limits of quantification range from 0.030 to 14 ng/g(dw). The use of APPI as an alternative ionization source helped to distinguish two isomeric musk fragrances by means of different ionization behavior. The method was demonstrated on sediment cores from Lake Greifensee located in northeastern Switzerland. The results show that biocides, musk fragrances, and other personal care products were the most frequently detected compounds with concentrations ranging from pg/g(dw) to ng/g(dw), whereas none of the targeted pharmaceuticals were found. The concentrations of many urban contaminants originating from wastewater correlate with the highest phosphorus input into the lake as a proxy for treatment efficiency. HRMS enabled a retrospective analysis of the full-scan data acquisition allowing the detection of suspected compounds like quaternary ammonium surfactants, the biocide triclocarban, and the tentative identification of further compounds without reference standards, among others transformation products of triclosan and triclocarban. PMID:23215447

  19. Ergot alkaloids in rye flour determined by solid-phase cation-exchange and high-pressure liquid chromatography with fluorescence detection

    DEFF Research Database (Denmark)

    Storm, Ida Marie Lindhardt Drejer; Rasmussen, Peter Have; Strobel, B.W.;

    2008-01-01

    Ergot alkaloids are mycotoxins that are undesirable contaminants of cereal products, particularly rye. A method was developed employing clean-up by cation-exchange solid-phase extraction, separation by high-performance liquid chromatography under alkaline conditions and fluorescence detection...

  20. Nontarget analysis of polar contaminants in freshwater sediments influenced by pharmaceutical industry using ultra-high-pressure liquid chromatography-quadrupole time-of-flight mass spectrometry

    International Nuclear Information System (INIS)

    A comprehensive analytical procedure for a reliable identification of nontarget polar contaminants in aquatic sediments was developed, based on the application of ultra-high-pressure liquid chromatography (UHPLC) coupled to hybrid quadrupole time-of-flight mass spectrometry (QTOFMS). The procedure was applied for the analysis of freshwater sediment that was highly impacted by wastewater discharges from the pharmaceutical industry. A number of different contaminants were successfully identified owing to the high mass accuracy of the QTOFMS system, used in combination with high chromatographic resolution of UHPLC. The major compounds, identified in investigated sediment, included a series of polypropylene glycols (n = 3-16), alkylbenzene sulfonate and benzalkonium surfactants as well as a number of various pharmaceuticals (chlorthalidone, warfarin, terbinafine, torsemide, zolpidem and macrolide antibiotics). The particular advantage of the applied technique is its capability to detect less known pharmaceutical intermediates and/or transformation products, which have not been previously reported in freshwater sediments. - Research highlights: → UHPLC-QTOFMS coupling was applied for nontarget analysis of polar contaminants. → Wide spectrum of polar contaminants was identified in polluted sediments. → Pharmaceuticals and their intermediates were present in high concentrations. - Comprehensive analysis of freshwater sediments by UPLC/QTOF indicated importance of pharmaceutically-derived polar contaminants.

  1. Trends in High Performance Liquid Chromatography for Cultural Heritage.

    Science.gov (United States)

    Degano, Ilaria; La Nasa, Jacopo

    2016-04-01

    The separation, detection and quantitation of specific species contained in a sample in the field of Cultural Heritage requires selective, sensitive and reliable methods. Procedures based on liquid chromatography fulfil these requirements and offer a wide range of applicability in terms of analyte types and concentration range. The main applications of High Performance Liquid Chromatography in this field are related to the separation and detection of dyestuffs in archaeological materials and paint samples by reversed-phase liquid chromatography with suitable detectors. The relevant literature will be revised, with particular attention to sample treatment strategies and future developments. Reversed phase chromatography has also recently gained increasing importance in the analysis of lipid binders and lipid materials in archaeological residues: the main advantages and disadvantages of the new approaches will be discussed. Finally, the main applications of ion chromatography and size exclusion chromatography in the field of Cultural Heritage will be revised in this chapter.

  2. Simultaneous pressurized enzymatic hydrolysis extraction and clean up for arsenic speciation in seafood samples before high performance liquid chromatography-inductively coupled plasma-mass spectrometry determination.

    Science.gov (United States)

    Moreda-Piñeiro, Jorge; Alonso-Rodríguez, Elia; Moreda-Piñeiro, Antonio; Moscoso-Pérez, Carmen; Muniategui-Lorenzo, Soledad; López-Mahía, Purificación; Prada-Rodríguez, Darío; Bermejo-Barrera, Pilar

    2010-10-29

    The feasibility of pressurized conditions to assist enzymatic hydrolysis of seafood tissues for arsenic speciation was novelty studied. A simultaneous in situ (in cell) clean-up procedure was also optimized, which speeds up the whole sample treatment. Arsenic species (As(III), MMA, DMA, As(V), AsB and AsC) were released from dried seafood tissues using pepsin as a protease, and the arsenic species were separated/quantified by anion exchange high performance liquid chromatography (HPLC) coupled to inductively coupled plasma-mass spectrometry (ICP-MS). Variables inherent to the enzymatic activity (pH, temperature and ionic strength), the amount of enzyme (pepsin), and factors affecting pressurization (pressure, static time, number of cycles and amount of dispersing agent, C-18) were fully evaluated. Pressurized assisted enzymatic hydrolysis (PAEH) with pepsin can be finished after few minutes (two cycles of 2 min each one plus 3 min to reach the hydrolysis temperature of 50 °C). A total sample solubilisation is not achieved after the procedure, however it is efficient enough for breaking down certain bonds of bio-molecules and for releasing arsenic species. The developed method has been found to be precise (RSDs lower than 6% for As(III), DMA and As(V); and 3% for AsB) and sensitive (LOQs of 18.1, 36.2, 35.7, 28.6, 20.6 and 22.5 ng/g for As(III), MMA, DMA, As(V), AsB and AsC, respectively). The optimized methodology was successfully applied to different certified reference materials (DORM-2 and BCR 627) which offer certified AsB and DMA contents, and also to different seafood products (mollusks, white fishes and cold water fishes).

  3. Dietary butyrylated high-amylose starch reduces azoxymethane-induced colonic O(6)-methylguanine adducts in rats as measured by immunohistochemistry and high-pressure liquid chromatography.

    Science.gov (United States)

    Le Leu, Richard K; Scherer, Benjamin L; Mano, Mark T; Winter, Jean M; Lannagan, Tamsin; Head, Richard J; Lockett, Trevor; Clarke, Julie M

    2016-09-01

    O(6)-methyl guanine (O(6)MeG) adducts are major toxic, promutagenic, and procarcinogenic adducts involved in colorectal carcinogenesis. Resistant starch and its colonic metabolite butyrate are known to protect against oncogenesis in the colon. In this study, we hypothesized that a dietary intervention that specifically delivers butyrate to the large bowel (notably butyrylated high-amylose maize starch [HAMSB]) would reduce colonic levels of O(6)MeG in rats shortly after exposure to the deoxyribonucleic acid (DNA) alkylating agent azoxymethane (AOM) when compared with a low-amylose maize starch (LAMS). A further objective was to validate an immunohistochemistry (IHC) method for quantifying O(6)MeG against a high-performance liquid chromatography method using fluorescence and diode array detection. Rats were fed either LAMS or HAMSB diets for 4 weeks followed by a single injection of AOM or saline and killed 6 hours later. After AOM exposure, both IHC and high-performance liquid chromatography method using fluorescence and diode array detection measured a substantially increased quantity of DNA adducts in the colon (P<.001). Both techniques demonstrated equally that consumption of HAMSB provided a protective effect by reducing colonic adduct load compared with the LAMS diet (P<.05). In addition, IHC allowed visualization of the O(6)MeG distribution, where adduct load was reduced in the lower third of the crypt compartment in HAMSB-fed rats (P=.036). The apoptotic response to AOM was higher in the HAMSB-fed rats (P=.002). In conclusion, the reduction in O(6)MeG levels and enhancement of the apoptotic response to DNA damage in the colonic epithelium through consumption of HAMSB provide mechanistic insights into how HAMSB protects against colorectal tumorigenesis. PMID:27632918

  4. Energy metabolism during microsurgical transfer of human skeletal muscle assessed by high-pressure liquid chromatography and by 31P-nuclear magnetic resonance.

    Science.gov (United States)

    Lundberg, Jonas; Elander, Anna; Rakotonirainy, Olivier; Zetterlund, Therese; Fogdestam, Ingemar; Soussi, Bassam

    2002-01-01

    The effect of ischaemia and reperfusion on human skeletal muscle was studied during free vascularised muscle transfer. Muscle biopsy specimens were taken from patients having microsurgical muscle transfer, 18 cases (17 patients; 12 men, 5 women). The biopsies were taken three times: before transfer of the muscle (control), at maximum ischaemic time, and one hour after revascularisation. The biopsy specimens were analysed for purine nucleotides, by high-pressure liquid chromatography (HPLC), and by nuclear magnetic resonance (NMR) at 500 MHz. Phosphocreatine (PCr) recovered only partially (79%) and adenosine triphosphate (ATP) did not differ significantly from normal control after revascularisation and a mean ischaemic time of 114 minutes. NMR measurements showed an accumulation of glucose-6-phosphate (G-6-P) during the ischaemic period, indicating anaerobic metabolism. After three hours of ischaemia and one hour of reperfusion the PCr recovery was less than 60% (r = 0.7). The results confirm those of previous animal studies, which set three hours normothermic ischaemia as a safe limit for tissue preservation when transferring skeletal muscle. Longer ischaemic times may cause serious postoperative healing problems and reduced muscle function.

  5. Exploring in vitro neurobiological effects and high-pressure liquid chromatography-assisted quantitation of chlorogenic acid in 18 Turkish coffee brands

    Directory of Open Access Journals (Sweden)

    Sinem Aslan Erdem

    2016-01-01

    Full Text Available The hydroalcoholic extracts of the Turkish traditional coffee samples from 18 commercial brands were tested for their neurobiological effects through enzyme inhibition based on enzyme-linked immunosorbance microtiter assays against acetylcholinesterase, butyrylcholinesterase, and tyrosinase, linked to Alzheimer's and Parkinson's diseases. The extracts were also subjected to several antioxidant test systems to define their antiradical, metal-chelation capacity, and reducing power. Total phenol and flavonoid contents in the extracts were delineated by spectrophotometric methods, while chlorogenic acid in the coffee samples was quantified by high-pressure liquid chromatography. The extracts displayed low to moderate inhibition (from 2.13 ± 0.01% to 36.12 ± 1.07% at 200 μg/mL against the tested enzymes, whereas they had notable 2,2′-diphenyl-1-picrylhydrazyl radical scavenging activity up to 56.15 ± 2.03% at 200 μg/mL. The extracts exerted a remarkable ferric-reducing antioxidant power values, while chlorogenic acid was found to range between 0.288 ± 0.005% and 2.335 ± 0.010%.

  6. Profiling of triacylglycerols in plant oils by high-performance liquid chromatography-atmosphere pressure chemical ionization mass spectrometry using a novel mixed-mode column.

    Science.gov (United States)

    Hu, Na; Wei, Fang; Lv, Xin; Wu, Lin; Dong, Xu-Yan; Chen, Hong

    2014-12-01

    In this investigation, a rapid and high-throughput method for profiling of TAGs in plant oils by liquid chromatography using a single column coupled with atmospheric pressure chemical ionization (APCI) mass spectrometry was reported. A novel mixed-mode phenyl-hexyl chromatographic column was employed in this separation system. The phenyl-hexyl column could provide hydrophobic interactions as well as π-π interactions. Compared with two traditionally columns used in TAG separation - the C18 column and silver-ion column, this column exhibited much higher selectivity for the separation of TAGs with great efficiency and rapid speed. By comparison with a novel mix-mode column (Ag-HiSep OTS column), which can also provide both hydrophobic interactions as well as π-π interactions for the separation of TAGs, phenyl-hexyl column exhibited excellent stability. LC method using phenyl-hexyl column coupled with APCI-MS was successfully applied for the profiling of TAGs in soybean oils, peanut oils, corn oils, and sesame oils. 29 TAGs in peanut oils, 22 TAGs in soybean oils, 19 TAGs in corn oils, and 19 TAGs in sesame oils were determined and quantified. The LC-MS data was analyzed by barcodes and principal component analysis (PCA). The resulting barcodes constitute a simple tool to display differences between different plant oils. Results of PCA also enabled a clear identification of different plant oils. This method provided an efficient and convenient chromatographic technology for the fast characterization and quantification of complex TAGs in plant oils at high selectivity. It has great potential as a routine analytical method for analysis of edible oil quality and authenticity control.

  7. Determination of six microcystins and nodularin in surface and drinking waters by on-line solid phase extraction-ultra high pressure liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Beltrán, Eduardo; Ibáñez, María; Sancho, Juan Vicente; Hernández, Félix

    2012-11-30

    Microcystins and nodularin are cyclic peptides hepatotoxins produced by cyanobacterial genera (blue-green algae). Toxic cyanobacterial blooms are a worldwide problem, as reported in several countries, like China, Australia, or the United States. Therefore, it is necessary to develop sensitive and reliable analytical methodology to determine this type of toxins in water at parts per billion levels, or even lower. In this work, the potential of solid-phase extraction coupled on-line to ultra-high-pressure liquid chromatography/electrospray tandem mass spectrometry (SPE-UHPLC-MS/MS) has been investigated for the efficient quantification and confirmation of microcystins LR, RR, YR, LY, LW, LF and nodularin in surface and drinking water samples, at sub-ppb levels. The method developed involves the injection of only 1 mL of water sample into the on-line SPE-UHPLC-MS/MS system and allows the rapid determination of the compounds selected (8 min of chromatographic run), avoiding laborious sample treatment. The method was validated in surface and drinking water by means of recovery experiments at 0.25 and 1 μg L(-1). Average recoveries (n=5) ranged from 71 to 116%, with relative standard deviations (RSDs) lower than 15%. For microcystins LR, RR, YR and nodularin, a third level was also assayed (0.1 μg L(-1)) obtaining satisfactory data too. Limits of detection between 0.002 and 0.0405 μg L(-1) were estimated (0.0005 μg L(-1) for nodularin). The developed method was applied to the analysis of water samples collected in the province of Castellón (Spain). The acquisition of three MS/MS transitions for each compound allowed the unequivocal confirmation of positive samples, which was supported by the accomplishment of ion intensity ratios and retention time when compared with reference standards. PMID:23107121

  8. Determination of Glucosamine in Human Plasma by High-Performance Liquid Chromatography-Atmospheric Pressure Chemical Ionization Source-Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Xingchen Zhou

    2011-01-01

    Full Text Available A sensitive, specific, and rapid high-performance liquid chromatography-atmospheric pressure chemical ionization source-tandem mass spectrometry (HPLC-APCI-MS/MS method for the determination of glucosamine in human plasma was developed and validated. Plasma samples were processed by protein precipitation with dehydrated ethanol, and the chromatographic separation was performed on an Agilent XDB-C18 column with a mobile phase of methanol—0.2% formic acid solution (70 : 30, v/v. Mass spectrometric quantification was carried out in the multiple reaction monitoring (MRM mode, monitoring ion transitions of m/z 180.1 to m/z 162.1 with collision energy (CE of 2 eV for glucosamine and m/z 181.1 to m/z 163.1 with CE of 2 eV for the internal standard (IS in positive ion mode. The linear calibration curves covered a concentration range of 53.27–3409 ng/mL with a lower limit of quantification (LLOQ of 53.27 ng/mL. The extraction recovery of glucosamine was greater than 101.7%. The intra- and interday precisions for glucosamine were less than 10%, and the accuracies were between 93.7% and 102.6%, determined from quality control (QC samples of three representative concentrations. The method has been successfully applied to determining the plasma concentration of glucosamine in a clinical pharmacokinetic study involving 20 healthy Chinese male volunteers.

  9. Ultra-high-pressure liquid chromatography tandem mass spectrometry determination of hallucinogenic drugs in hair of psychedelic plants and mushrooms consumers.

    Science.gov (United States)

    Pichini, Simona; Marchei, Emilia; García-Algar, Oscar; Gomez, Arelis; Di Giovannandrea, Rita; Pacifici, Roberta

    2014-11-01

    A procedure based on ultra-high-pressure liquid chromatography tandem mass spectrometry has been developed for the determination of mescaline, N,N-dimethyltryptamine, psilocin, psilocybin, salvinorin A in hair of consumers of psychedelic vegetal material such peyote or trichocereus cacti, psilocybe mushrooms, Salvia divinorum or psychedelic beverage ayahuasca. After hair washing with methyl alcohol and diethyl ether and subsequent addition of mescaline-d9 and 3,4-methylenedioxypropylamphetamine as internal standards, hair samples were treated with 250μl VMA-T M3 reagent for 1h at 100°C. After cooling, 100μl M3 extract were diluted with 400μl water and a volume of 10μl was injected into chromatographic system. Chromatographic separation was achieved at ambient temperature using a reverse-phase column and a linear gradient elution with two solvents: 0.3% formic acid in acetonitrile and 5mM ammonium formate pH 3. The mass spectrometer was operated in positive ion mode, using multiple reaction monitoring via positive electrospray ionization. The method was linear from the limit of quantification (0.03-0.05ng/mg depending on analyte under investigation) to 10ng/mg hair, with an intra- and inter-assay imprecision and inaccuracy always less than 15% and an analytical recovery between 79.6% and 97.4%, depending on the considered analyte. Using the validated method, mescaline was found in concentration range of 0.08-0.13ng/mg in hair of peyote smokers, 3.2ng salvinorin A per mg hair were determined in hair from a S. divinorum smoker, 5.6ng N,N-dimethyltryptamine per mg hair from an ayahuasca user and finally 0.8ng psilocybin per ng hair of a psilocybe consumer. PMID:25171488

  10. Multi-mycotoxin analysis in eggs using a QuEChERS-based extraction procedure and ultra-high-pressure liquid chromatography coupled to triple quadrupole mass spectrometry.

    Science.gov (United States)

    Frenich, Antonia Garrido; Romero-González, Roberto; Gómez-Pérez, María Luz; Vidal, José Luis Martínez

    2011-07-15

    A reliable and rapid method has been developed for the determination of 10 mycotoxins (beauvericin, enniatin A, A1, B1, citrinin, aflatoxin B1, B2, G1, G2 and ochratoxin A) in eggs at trace levels. Ultra-high-pressure liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) has been used for the analysis of these compounds in less than 7 min. Mycotoxins have been extracted from egg samples using a QuEChERS-based extraction procedure (Quick, Easy, Cheap, Effective, Rugged and Safe) without applying any further clean-up step. Extraction, chromatographic and detection conditions were optimised in order to increase sample throughput and sensitivity. Matrix-matched calibration was used for quantification. Blank samples were fortified at 10, 25, 50 and 100 μg kg(-1), and recoveries ranged from 70% to 110%, except for ochratoxin A and aflatoxin G1 at 10 μg kg(-1), and aflatoxin G2 at 50 μg kg(-1). Relative standard deviations were lower than 25% in all the cases. Limits of detection ranged from 0.5 μg kg(-1) (for aflatoxins B1, B2 and G1) to 5 μg kg(-1) (for enniatin A, citrinin and ochratoxin A) and limits of quantification ranged from 1 μg kg(-1) (for aflatoxins B1, B2 and G1) to 10 μg kg(-1) (for enniatin A, citrinin and ochratoxin A). Seven samples were analyzed and aflatoxins B1, B2, G1, G2, and beauvericin were detected at trace levels. PMID:21621786

  11. Ultra-high-pressure liquid chromatography tandem mass spectrometry determination of antidepressant and anxiolytic drugs in neonatal meconium and maternal hair.

    Science.gov (United States)

    Pichini, Simona; Cortes, Laura; Marchei, Emilia; Solimini, Renata; Pacifici, Roberta; Gomez-Roig, Maria Dolores; García-Algar, Oscar

    2016-01-25

    A procedure based on ultra-high-pressure liquid chromatography tandem mass spectrometry has been developed for the determination of 22 antidepressant and anxiolytic drugs ad metabolites in the three consecutive maternal hair segments representing the pregnancy trimesters and paired neonatal meconium samples. After hair washing with methyl alcohol and diethyl ether and subsequent addition of internal standards, hair samples were treated with 500 μl VMA-T M3 reagent for 1h at 100 °C. After cooling, 100 μl M3 extract were diluted with 400 μl water and a volume of 10 μl was injected into chromatographic system. Meconium samples were firstly treated with 1 ml methyl alcohol and the organic layer back-extracted twice with 1.5 ml of a mixture of ethylacetate:hexane (80:20, v/v). Chromatographic separation was achieved at ambient temperature using a reverse-phase column and a linear gradient elution with two solvents: 0.3% formic acid in acetonitrile and 5mM ammonium formate pH 3. The mass spectrometer was operated in positive ion mode, using multiple reaction monitoring via positive electrospray ionization. The method was linear from the limit of quantification (0.05-1 ng/mg hair and 5-25 ng/g meconium depending on analyte under investigation;) to 10 ng/mg hair and 1000 ng/g meconium, with an intra- and inter-assay imprecision and inaccuracy always less than 20% and an analytical recovery between 66.6% and 95.3%, depending on the considered analyte and biological matrix. Using the validated method, 7 mothers were found positive to one or more hair segments and 5 meconium samples were found positive to one or more antidepressant and anxiolytic drugs, assessing prenatal exposure to these drugs following maternal consumption in one or more pregnancy trimesters.

  12. Ultra-high-pressure liquid chromatography tandem mass spectrometry determination of hallucinogenic drugs in hair of psychedelic plants and mushrooms consumers.

    Science.gov (United States)

    Pichini, Simona; Marchei, Emilia; García-Algar, Oscar; Gomez, Arelis; Di Giovannandrea, Rita; Pacifici, Roberta

    2014-11-01

    A procedure based on ultra-high-pressure liquid chromatography tandem mass spectrometry has been developed for the determination of mescaline, N,N-dimethyltryptamine, psilocin, psilocybin, salvinorin A in hair of consumers of psychedelic vegetal material such peyote or trichocereus cacti, psilocybe mushrooms, Salvia divinorum or psychedelic beverage ayahuasca. After hair washing with methyl alcohol and diethyl ether and subsequent addition of mescaline-d9 and 3,4-methylenedioxypropylamphetamine as internal standards, hair samples were treated with 250μl VMA-T M3 reagent for 1h at 100°C. After cooling, 100μl M3 extract were diluted with 400μl water and a volume of 10μl was injected into chromatographic system. Chromatographic separation was achieved at ambient temperature using a reverse-phase column and a linear gradient elution with two solvents: 0.3% formic acid in acetonitrile and 5mM ammonium formate pH 3. The mass spectrometer was operated in positive ion mode, using multiple reaction monitoring via positive electrospray ionization. The method was linear from the limit of quantification (0.03-0.05ng/mg depending on analyte under investigation) to 10ng/mg hair, with an intra- and inter-assay imprecision and inaccuracy always less than 15% and an analytical recovery between 79.6% and 97.4%, depending on the considered analyte. Using the validated method, mescaline was found in concentration range of 0.08-0.13ng/mg in hair of peyote smokers, 3.2ng salvinorin A per mg hair were determined in hair from a S. divinorum smoker, 5.6ng N,N-dimethyltryptamine per mg hair from an ayahuasca user and finally 0.8ng psilocybin per ng hair of a psilocybe consumer.

  13. High Performance Liquid Chromatography Experiments to Undergraduate Laboratories

    Science.gov (United States)

    Kissinger, Peter T.; And Others

    1977-01-01

    Reviews the principles of liquid chromatography with electrochemical detection (LCEC), an analytical technique that incorporates the advantages of both liquids chromatography and electrochemistry. Also suggests laboratory experiments using this technique. (MLH)

  14. Structures of Liquid Aluminium under High Pressure

    Institute of Scientific and Technical Information of China (English)

    LI Hui; WANG Guang-Hou; BIAN Xiu-Fang; ZHANG Lin

    2001-01-01

    Molecular dynamics simulation has been carried out for melt A1 under constant temperature and constant pressure. The interaction between atoms is described by tight-binding many-body potentials based on the second moment approximation to the electronic density of states. The pair correlation function and the pair analysis technique are used to reveal the structural features of liquid Al under normal and high pressure. High pressure is favourable to the existence of bcc clusters 1661 and 1441, but has no effect on the fcc cluster 1421. The bond pair 1551 and 1541 with fivefold symmetry exists at high pressure. The microstructure of liquid is more similar to the non-crystalline structure than to the crystalline structure. The simulation results are supported by thex-ray experimental results.

  15. Monitoring aged reversed-phase high performance liquid chromatography columns

    NARCIS (Netherlands)

    Bolck, A; Smilde, AK; Bruins, CHP

    1999-01-01

    In this paper, a new approach for the quality assessment of routinely used reversed-phase high performance liquid chromatography columns is presented. A used column is not directly considered deteriorated when changes in retention occur. If attention is paid to the type and magnitude of the changes,

  16. Mallow carotenoids determined by high-performance liquid chromatography

    Science.gov (United States)

    Mallow (corchorus olitorius) is a green vegetable, which is widely consumed either fresh or dry by Middle East population. This study was carried out to determine the contents of major carotenoids quantitatively in mallow, by using a High Performance Liquid Chromatography (HPLC) equipped with a Bis...

  17. High-Performance Liquid Chromatography-Mass Spectrometry.

    Science.gov (United States)

    Vestal, Marvin L.

    1984-01-01

    Reviews techniques for online coupling of high-performance liquid chromatography with mass spectrometry, emphasizing those suitable for application to nonvolatile samples. Also summarizes the present status, strengths, and weaknesses of various techniques and discusses potential applications of recently developed techniques for combined liquid…

  18. Quantification of Tea Flavonoids by High Performance Liquid Chromatography

    Science.gov (United States)

    Freeman, Jessica D.; Niemeyer, Emily D.

    2008-01-01

    We have developed a laboratory experiment that uses high performance liquid chromatography (HPLC) to quantify flavonoid levels in a variety of commercial teas. Specifically, this experiment analyzes a group of flavonoids known as catechins, plant-derived polyphenolic compounds commonly found in many foods and beverages, including green and black…

  19. Profiling of steroid metabolites after transdermal and oral administration of testosterone by ultra-high pressure liquid chromatography coupled to quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Badoud, F; Boccard, J; Schweizer, C; Pralong, F; Saugy, M; Baume, N

    2013-11-01

    The screening of testosterone (T) misuse for doping control is based on the urinary steroid profile, including T, its precursors and metabolites. Modifications of individual levels and ratio between those metabolites are indicators of T misuse. In the context of screening analysis, the most discriminant criterion known to date is based on the T glucuronide (TG) to epitestosterone glucuronide (EG) ratio (TG/EG). Following the World Anti-Doping Agency (WADA) recommendations, there is suspicion of T misuse when the ratio reaches 4 or beyond. While this marker remains very sensitive and specific, it suffers from large inter-individual variability, with important influence of enzyme polymorphisms. Moreover, use of low dose or topical administration forms makes the screening of endogenous steroids difficult while the detection window no longer suits the doping habit. As reference limits are estimated on the basis of population studies, which encompass inter-individual and inter-ethnic variability, new strategies including individual threshold monitoring and alternative biomarkers were proposed to detect T misuse. The purpose of this study was to evaluate the potential of ultra-high pressure liquid chromatography (UHPLC) coupled with a new generation high resolution quadrupole time-of-flight mass spectrometer (QTOF-MS) to investigate the steroid metabolism after transdermal and oral T administration. An approach was developed to quantify 12 targeted urinary steroids as direct glucuro- and sulfo-conjugated metabolites, allowing the conservation of the phase II metabolism information, reflecting genetic and environmental influences. The UHPLC-QTOF-MS(E) platform was applied to clinical study samples from 19 healthy male volunteers, having different genotypes for the UGT2B17 enzyme responsible for the glucuroconjugation of T. Based on reference population ranges, none of the traditional markers of T misuse could detect doping after topical administration of T, while the

  20. Determination of gemcitabine and its metabolite in human plasma using high-pressure liquid chromatography coupled with a diode array detector

    Institute of Scientific and Technical Information of China (English)

    Neng-ming LIN; Su ZENG; Sheng-lin MA; Yun FAN; Hai-jun ZHONG; Luo FANG

    2004-01-01

    AIM: To establish a high pressure liquid chromatography (HPLC) method for determination of the concentration of gemcitabine (dFdC) and its metabolite (dFdU) in human plasma. METHODS: Plasma 1.0mL spiked with floxuridine as an internal standard was extracted with 3.0 mL of methanol-acetonitrile (v/v, 1:9). The supernatant was evaporated at 60 ℃ and the residue was reconstituted with 0.5 mL of the solution used as the mobile phase. After centrifugation, 50 μL of the supernatant was injected into the HPLC system. Separation was achieved on a C18(4.6 mm×250 mm, 5μm) column at 25℃ with the flow rate of the mobile phase set to 0.8 mL/min. The compounds were detected at 268 nm. The mobile phase consisted of 40.0 mmol/L acetate ammonium buffer solution (pH 5.5) and acetonitrile (v/v, 97.5:2.5). RESULTS: The linear range was 0.20-10.0 mg/L (r=0.9999) for dFdC and 0.50-50.0 mg/L (r=0.9999) for dFdU. The limit of detection (LOD) was 0.10 mg/L for dFdC and 0.25mg/L for dFdU, while the limit of quantification (LOQ) was 0.20 mg/L (RSD<10%) for dFdC and 0.50 mg/L (RSD <3%) for dFdU. The average recovery of dFdC and dFdU by this method were 103.3% and 98.7%, respectively.For intra-day and inter-day, the corresponding standard deviations of the measurements of dFdC and dFdU were both less than 5.5%. CONCLUSION: An analytical method was established to measure the concentrations of dFdC and dFdU in human plasma and was effectively applied to the dFdC and dFdU pharmacokinetic studies of 8Chinese patients with malignant tumors.

  1. Determination of benzoylurea insecticide residues in tomatoes by high-performance liquid chromatography with ultraviolet-diode array and atmospheric pressure chemical ionization-mass spectrometry detection.

    Science.gov (United States)

    Markoglou, Anastasios N; Bempelou, Eleftheria D; Liapis, Konstantinos S; Ziogas, Basil N

    2007-01-01

    A simple and sensitive method using high-performance liquid chromatography/ mass spectrometry (LC/MS) was developed and validated for simultaneous determination of 5 benzoylurea insecticides-diflubenzuron, triflumuron, teflubenzuron, lufenuron, and flufenoxuron-in tomatoes. Residues were successfully separated on a C18 column by methanol-water isocratic elution. Detection was carried out by an ultraviolet diode array detector (UV-DAD) coupled with a quadrupole mass spectrometer, using atmospheric pressure chemical ionization (APCI) in negative-ion mode. The main ions were the deprotonated molecules [M-H]- for triflumuron, and the anions formed by elimination of hydrofluoric acid [M-H-HF]- for diflubenzuron and flufenoxuron, and [M-2H-HF] for lufenuron and teflubenzuron. The calibration plots were linear for both detectors over the range 0.05 to 10 microg/mL, and the method presented good quality parameters. The limits of detection for standard solutions were 0.008-0.01 mg/L (equivalent to 0.08-0.1 ng injected) for both detectors, and the limits of quantification (LOQs) were approximately 10 times lower than national maximum residue levels (MRLs). Depending on the compound and the detector, the LOQ values ranged from 0.2 to 0.4 ng injected. The optimum LC-UV-DAD/APCI-MS conditions were applied to the analysis of benzoylureas in tomatoes. The obtained recoveries from fortified tomato samples (50 g), extracted with ethyl acetate and purified by solid-phase extraction on silica sorbent, were 88-100 and 92.9-105% for the UV-DAD and MS detectors, respectively, with precision values (relative standard deviations) of 2.9-11 and 3.7-14%, respectively. The method was applied to 12 tomato samples from local markets, and diflubenzuron and lufenuron were detected in only one sample at concentrations lower than the MRLs. The results indicate that the developed LC/MS method is accurate, precise, and sensitive for quantitative and qualitative analysis at low levels of benzoylureas

  2. High-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry and gas chromatography-flame ionization detection characterization of Delta5-polyenoic fatty acids in triacylglycerols from conifer seed oils.

    Science.gov (United States)

    Lísa, Miroslav; Holcapek, Michal; Rezanka, Tomás; Kabátová, Nadezda

    2007-03-30

    Edible conifer seeds can serve as a source of triacylglycerols (TGs) with unusual Delta5 unsaturated polymethylene interrupted fatty acids (UPIFAs), such as cis-5,9-octadecadienoic (taxoleic), cis-5,9,12-octadecatrienoic (pinolenic), cis-5,11-eicosadienoic (keteleeronic) and cis-5,11,14-eicosatrienoic acids (sciadonic). Conifer seed oils from European Larch (Larix decidua), Norway Spruce (Picea abies) and European Silver Fir (Abies alba) have been analyzed by non-aqueous reversed-phase high-performance liquid chromatography (NARP-HPLC) with atmospheric pressure chemical ionisation (APCI)-MS detection. The influence of different positions of double bonds in Delta5-UPIFAs on the retention and fragmentation behavior is described and used for the successful identification of TGs in each oil. TGs containing Delta5-UPIFAs have a higher retention in comparison with common TGs found in plant oils with single methylene interrupted Delta6(9)-FAs and also significantly changed relative abundances of fragment ions in APCI mass spectra. Results obtained from HPLC/MS analyses are supported by validated GC/FID analyses of fatty acid methyl esters after the transesterification. The total content of Delta5-UPIFAs is about 32% for European Larch, 27% for Norway Spruce and 20% for European Silver Fir. In total, 20 FAs with acyl chain lengths from 16 to 24 carbon atoms and from 0 to 3 double bonds have been identified in 64 triacylglycerols from 3 conifer seed oils. PMID:17307191

  3. Rapid method for simultaneous determination of flavonoid, saponins and polyacetylenes in folium ginseng and radix ginseng by pressurized liquid extraction and high-performance liquid chromatography coupled with diode array detection and mass spectrometry.

    Science.gov (United States)

    Qian, Z M; Lu, J; Gao, Q P; Li, S P

    2009-05-01

    A rapid pressurized liquid extraction (PLE) and high-performance liquid chromatography coupled with diode array detection and mass spectrometry (HPLC-DAD-MS) method for the simultaneous determination of one flavonoid (panasenoside), nine saponins (ginsenoside Rg1, Re, Rf, Rg2, Rb1, Rc, Rb2, Rb3 and Rd) and two polyacetylenes (panaxydol and panaxynol) in folium ginseng and radix ginseng was developed. A Prevail C(18) rocket column (33 mm x 7 mm, 3.0 microm) and gradient elution were used during the analysis. Flavonoid was quantified at 355 nm, and saponins and polyacetylenes were determined at 203 nm. The chromatographic peaks of 12 investigated compounds in samples were unambiguously identified by compared their UV spectra and/or MS data with the related reference compounds. All calibration curves showed good linearity (r>0.999) within the test ranges. The intra- and inter-day variations for 12 analytes were less than 1.17% and 2.17%, respectively. The developed method was successfully applied to determine the investigated compounds in 10 samples of radix ginseng and folium ginseng, respectively. The result showed that PLE combined with rocket column HPLC analysis could provide a rapid method for analysis of compounds in traditional Chinese medicines (TCMs), which is helpful to comprehensive evaluation of quality of radix ginseng and folium ginseng. PMID:19272605

  4. Parallel ultra high pressure liquid chromatography-mass spectrometry for the quantification of HIV protease inhibitors using dried spot sample collection format.

    Science.gov (United States)

    Watanabe, Kyoko; Varesio, Emmanuel; Hopfgartner, Gérard

    2014-08-15

    An assay was developed and validated for the quantification of eight protease inhibitors (indinavir (IDV), ritonavir (RTV), lopinavir (LPV), saquinavir (SQV), amprenavir (APV), nelfinavir (NFV), atazanavir (AZV) and darunavir (DRV)) in dried plasma spots using parallel ultra-high performance liquid chromatography and mass spectrometry detection in the multiple reaction monitoring mode. For each analyte an isotopically labeled internal standard was used and the assay based on liquid-solid extraction the area response ratio (analyte/IS) was found to be linear; from 0.025 μg/ml to 20 μg/ml for IDV, SQV, DRV, AZV, LPV, from 0.025 μg/ml to 10 μg/ml for NFV, APV and from 0.025 μg/ml to 5 μg/ml for RTV using 15 μl of plasma spotted on filter paper placed in a sample tube. The total analysis time was of 4 min and inter-assay accuracies and precisions were in the range of 87.7-109% and 2.5-11.8%, respectively. On dried plasma spots all analytes were found to be stable for at least 7 days. Practicability of the assay to blood was also demonstrated. The sample drying process could be reduced to 5 min using a commercial microwave system without any analyte degradation. Together with quantification, confirmatory analysis was performed on representative clinical samples. PMID:25049214

  5. High-pressure liquid chromatographic gradient mixer

    Science.gov (United States)

    Daughton, C.G.; Sakaji, R.H.

    1982-09-08

    A gradient mixer effects the continuous mixing of any two miscible solvents without excessive decay or dispersion of the resultant isocratic effluent or of a linear or exponential gradient. The two solvents are fed under low or high pressure by means of two high performance liquid chromatographic pumps. The mixer comprises a series of ultra-low dead volume stainless steel tubes and low dead volume chambers. The two solvent streams impinge head-on at high fluxes. This initial nonhomogeneous mixture is then passed through a chamber packed with spirally-wound wires which cause turbulent mixing thereby homogenizing the mixture with minimum band-broadening.

  6. High pressure liquid chromatographic gradient mixer

    Science.gov (United States)

    Daughton, Christian G.; Sakaji, Richard H.

    1985-01-01

    A gradient mixer which effects the continuous mixing of any two miscible solvents without excessive decay or dispersion of the resultant isocratic effluent or of a linear or exponential gradient. The two solvents are fed under low or high pressure by means of two high performance liquid chromatographic pumps. The mixer comprises a series of ultra-low dead volume stainless steel tubes and low dead volume chambers. The two solvent streams impinge head-on at high fluxes. This initial nonhomogeneous mixture is then passed through a chamber packed with spirally-wound wires which cause turbulent mixing thereby homogenizing the mixture with minimum "band-broadening".

  7. Characterization of typical chemical background interferences in atmospheric pressure ionization liquid chromatography-mass spectrometry

    NARCIS (Netherlands)

    Guo, Xinghua; Bruins, Andries P.; Covey, Thomas R.

    2006-01-01

    The structures and origins of typical chemical background noise ions in positive atmospheric pressure ionization liquid chromatography/mass spectrometry (API LC/MS) are investigated and summarized in this study. This was done by classifying chemical background ions using precursor and product ion sc

  8. Use of ammonium formate in QuEChERS for high-throughput analysis of pesticides in food by fast, low-pressure gas chromatography and liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    González-Curbelo, Miguel Ángel; Lehotay, Steven J; Hernández-Borges, Javier; Rodríguez-Delgado, Miguel Ángel

    2014-09-01

    The "quick, easy, cheap, effective, rugged, and safe" (QuEChERS) approach to sample preparation is widely applied in pesticide residue analysis, but the use of magnesium sulfate and other nonvolatile compounds for salting out in the method is not ideal for mass spectrometry. In this study, we developed and evaluated three new different versions of the QuEChERS method using more volatile salts (ammonium chloride and ammonium formate and acetate buffers) to induce phase separation and extraction of 43 representative pesticide analytes of different classes. Fast low-pressure gas chromatography tandem mass spectrometry (LPGC-MS/MS) and liquid chromatography (LC)-MS/MS were used for analysis. The QuEChERS AOAC Official Method 2007.01 was also tested for comparison purposes. Of the studied methods, formate buffering using 7.5g of ammonium formate and 15mL of 5% (v/v) formic acid in acetonitrile for the extraction of 15g of sample (5g for wheat grain) provided the best performance and practical considerations. Method validation was carried out with and without the use of dispersive solid-phase extraction for cleanup, and no significant differences were observed for the majority of pesticides. The method was demonstrated in quantitative analysis for GC- and LC-amenable pesticides in 4 representative food matrices (apple, lemon, lettuce, and wheat grain). With the typical exceptions of certain pH-dependent and labile pesticides, 90-110% recoveries and food applications.

  9. Profiling of compounds and degradation products from the postharvest treatment of pears and apples by ultra-high pressure liquid chromatography quadrupole-time-of-flight mass spectrometry.

    Science.gov (United States)

    Picó, Yolanda; la Farré, Marinel; Segarra, Ramon; Barceló, Damià

    2010-04-15

    This study deals with a simple strategy to pinpoint potential unknown compounds in full scan mass spectrometry (MS) experiments. Forty samples of apples and pears intended for human consumption were analyzed by ultra-high performance liquid chromatography quadrupole-time-of-flight (UPLC-QqTOF-MS), after extraction of the possible contaminants by rinsing the peel of the fruit with ethyl acetate. The peaks were visually recognized in the total ion chromatogram (TIC). Two major types of postharvest treatments were detected in this set of samples: imazalil (IMZ)/ethoxyquin (EQ) and thiabendazole (TBZ)/diphenylamine (DPA). The present work also describes the metabolites formed by degradation of EQ (to our knowledge not previously reported) and DPA (there was mass spectral evidence of some of them but full identification was not pursued). Hydroxy-DPA, n-phenyl-4-quinoneimine, methoxy-DPA, demethyl-EQ, demethyldehydro-EQ, EQ-dimer, methyl-EQ, EQ-N-oxyl and 2',2,4,-trimethyl-6-quinolone were unequivocally identified and confirmed. Some relationships between the applied postharvest treatment and the metabolites formed were established. Remarkably, they may constitute a useful fingerprint in further investigations of postharvest treatments. Among other significant results, the study also reveals for the first time the presence of some EQ metabolites in fruits, which are different from those previously reported in animal tissues. There is not information on the occurrence of EQ metabolites in fruits and the DPA ones have not been studied extensively in pears and apples. The levels of the metabolites found exceeded several times those of the parent compounds.

  10. Evaluation of interactions between metal ions and nonionic surfactants in high-concentration HCl using low-pressure high-performance liquid chromatography with low-flow-resistance polystyrene-based monolithic column.

    Science.gov (United States)

    Hirano, Tomohiko; Kitagawa, Shinya; Ohtani, Hajime; Kinoshita, Takehiko; Ishigaki, Yuzo; Shibata, Nobuyuki; Nii, Susumu

    2013-10-01

    A method for evaluating the interactions between metal ions and nonionic surfactants in aqueous solutions containing high-concentration HCl, using gas pressure-driven low-pressure high-performance liquid chromatography (LP-HPLC) as a highly acid-resistant HPLC system, was developed. To construct the LP-HPLC for this purpose, poly(styrene-co-divinylbenzene)-based low-flow-resistance monolithic columns tolerant to highly acidic conditions were prepared using low-conversion thermal polymerization. Thermal polymerization at 65 °C for 1.5 h (monomer conversions, 33% for styrene and 59% for divinylbenzene) allowed preparation of a column with both high separation efficiency (around 60,000 plates m(-1) for alkylbenzenes) and a quite low back pressure of 0.14 MPa at a linear flow rate of 1 mm s(-1) (2.8 × 10(-13) m(2) in permeability). The base column prepared under the above conditions was coated with a nonionic surfactant, polyoxyethylene nonylphenyl ether (PONPE, average oxyethylene unit numbers (n) = 3, 7.5, 15, and 20), and used for evaluation of the interactions between PONPEs and metal ions in 6 M HCl. The interactions between PONPEs and Au(III), Ga(III), Fe(III), Zn(II), and Cu(II) were successfully evaluated using both breakthrough and chromatographic methods. Furthermore, a study of the effect of the polyoxyethylene (POE) chain length revealed that the use of PONPE with the longer POE moiety enhanced the magnitude of the interaction together with the increase in the amount of oxyethylene (OE) units coated on the monolith. Moreover, the interactions of metal ions with a single OE unit were almost constant in the range of n = 7.5-20, whereas the suppression of the interaction between Au(III) with the shortest PONPE chain (n = 3) was also observed. PMID:23884474

  11. Analysis of ganciclovir and its related substances using high performance liquid chromatography and liquid chromatography-mass spectrometry methods

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Objective High performance liquid chromatography(HPLC)and liquid chromatography-mass spectrometry(LC/MS)methods were developed for the determination of ganciclovir and its related substances.Methods A Hypersil ODS2 column(4.6 mm×250 mm,5 μm)was used with a mobile phase of 0.02 M potassium dihydrogen phosphate buffer(pH 6.0)-methanol(92∶8)at a flow rate of 1.0 mL/min,and UV detector set at 254 nm was used for monitoring the eluents.Results The method was simple,rapid,selective and capable of separating all r...

  12. High Performance Liquid Chromatography of Vitamin A: A Quantitative Determination.

    Science.gov (United States)

    Bohman, Ove; And Others

    1982-01-01

    Experimental procedures are provided for the quantitative determination of Vitamin A (retinol) in food products by analytical liquid chromatography. Standard addition and calibration curve extraction methods are outlined. (SK)

  13. Determination of tetracycline residues in soil by pressurized liquid extraction and liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Andreu, Vicente; Vazquez-Roig, Pablo; Blasco, Cristina; Picó, Yolanda

    2009-07-01

    An optimized extraction and cleanup method for the analysis of chlortetracycline (CTC), doxycycline (DC), oxytetracycline (OTC) and tetracycline (TC) in soil is presented. Soil extraction in a pressurized liquid extraction system, followed by extract clean up using solid-phase extraction (SPE) and tetracycline determination by liquid chromatography tandem mass spectrometry (LC-MS/MS) provided appropriate efficiency and reproducibility. Different dispersing agents and solvents for soil extraction and several SPE cartridges for cleanup were compared. The best extraction results were obtained using ethylenediamine tetraacetic acid-treated sand as dispersing agent, and water at 70 degrees C. The most effective cleanup was obtained using Strata-X sorbent in combination with a strong anion exchange cartridge. Recoveries ranged from 71% to 96% and precision, as indicated by the relative standard deviations, was within the range of 8-15%. The limits of quantification (LOQs) by using LC-MS/MS, based on signal-to-noise ratio (S/N) of 10, ranged from 1 microg kg(-1) for TC to 5 microg kg(-1) for CTC. These results pointed out that this technique is appropriate to determine tetracyclines in soils. Analysis of 100 samples taken in the Valencian Community revealed that, in soil, up to 5 microg kg(-1) CTC, 15 microg kg(-1) OTC, 18 microg kg(-1) TC, and 12 microg kg(-1) DC could be detected. Detection of the analytes in several samples, which typify great part of the Spanish agricultural soils, should be outlined as most important result of this study. PMID:19205670

  14. Chemical Investigation of Saponins in Different Parts of Panax notoginseng by Pressurized Liquid Extraction and Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometry

    OpenAIRE

    Si-Jia Hong; Peng Li; Yi-Tao Wang; Shao-Ping Li; Qing-Wen Zhang; Jian-Bo Wan

    2012-01-01

    A pressurized liquid extraction (PLE) and high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) method was developed for the qualitative determination of saponins in different parts of P. notoginseng, including rhizome, root, fibre root, seed, stem, leaf and flower. The samples were extracted using PLE. The analysis was achieved on a Zorbax SB-C18 column with gradient elution of acetonitrile and 8 mM aqueous ammonium acet...

  15. Temperature-controlled ionic liquid dispersive liquid phase microextraction combined with ultra-high-pressure liquid chromatography for the rapid determination of triclosan,triclocarban and methyl-triclosan in aqueous samples

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    As extraction solvents,ionic liquids have green characteristics.In this study,an environmentally benign analytical method termed temperature-controlled ionic liquid dispersive liquid phase microextraction (TIL-DLME) combined with ultra-highpressure liquid chromatography (UHPLC)-tunable ultraviolet detection (TUV) was developed for the pre-concentration and determination of triclosan (TCS),triclocarban (TCC) and methyl-triclosan (M-TCS) in water samples.Significant parameters that may affect extraction efficiencies were examined and optimized,including the types and amount of ionic liquids,volume of the diluent,heating temperature,cooling time,salt effect and pH value.Under the optimum conditions,linearity of the method was observed in the ranges of 0.0100-100 μgL-1 for TCS and M-TCS,and 0.00500-50.0 μgL-1 for TCC with correlation coefficients (r2) > 0.9903.The limits of detection (LODs) ranged from 1.15 to 5.33 ngL-1.TCS in domestic water and TCC in reclaimed water were detected at the concentrations of 1.01 and 0.126 μgL-1,respectively.The spiked recoveries of the three target compounds in reclaimed water,irrigating water,waste water and domestic water samples were obtained in the ranges of 68.4%-71.9%,61.6%-87.8%,58.9%-74.9% and 64.9%-92.4%,respectively.Compared with the previous dispersive liquid-liquid microextraction method (DLLME) about the determination of TCS,TCC and M-TCS,this method is not only more environmentally friendly but also more sensitive.

  16. Improving Liquid Chromatography-Mass Spectrometry Sensitivity Using a Subambient Pressure Ionization with Nanoelectrospray (SPIN) Interface

    Science.gov (United States)

    Tang, Keqi; Page, Jason S.; Marginean, Ioan; Kelly, Ryan T.; Smith, Richard D.

    2011-08-01

    In this work, the subambient pressure ionization with nanoelectrospray (SPIN) ion source and interface, which operates at ~15-30 Torr, is demonstrated to be compatible with gradient reversed-phase liquid chromatography-MS applications, exemplified here with the analysis of complex samples (a protein tryptic digest and a whole cell lysate). A low liquid chromatographic flow rate (100-400 nL/min) allowed stable electrospray to be established while avoiding electrical breakdown. Efforts to increase the operating pressure of the SPIN source relative to previously reported designs prevented solvent freezing and enhanced charged cluster/droplet desolvation. A 5- to 12-fold improvement in sensitivity relative to a conventional atmospheric pressure nanoelectrospray ionization (ESI) source was obtained for detected peptides.

  17. Method development for the determination of 24S-hydroxycholesterol in human plasma without derivatization by high-performance liquid chromatography with tandem mass spectrometry in atmospheric pressure chemical ionization mode.

    Science.gov (United States)

    Sugimoto, Hiroshi; Kakehi, Masaaki; Satomi, Yoshinori; Kamiguchi, Hidenori; Jinno, Fumihiro

    2015-10-01

    We developed a highly sensitive and specific high-performance liquid chromatography with tandem mass spectrometry method with an atmospheric pressure chemical ionization interface to determine 24S-hydroxycholesterol, a major metabolite of cholesterol formed by cytochrome P450 family 46A1, in human plasma without any derivatization step. Phosphate buffered saline including 1% Tween 80 was used as the surrogate matrix for preparation of calibration curves and quality control samples. The saponification process to convert esterified 24S-hydroxycholesterol to free sterols was optimized, followed by liquid-liquid extraction using hexane. Chromatographic separation of 24S-hydroxycholesterol from other isobaric endogenous oxysterols was successfully achieved with gradient mobile phase comprised of 0.1% propionic acid and acetonitrile using L-column2 ODS (2 μm, 2.1 mm id × 150 mm). This assay was capable of determining 24S-hydroxycholesterol in human plasma (200 μL) ranging from 1 to 100 ng/mL with acceptable intra- and inter-day precision and accuracy. The potential risk of in vitro formation of 24S-hydroxycholesterol by oxidation from endogenous cholesterol in human plasma was found to be negligible. The stability of 24S-hydroxycholesterol in relevant solvents and human plasma was confirmed. This method was successfully applied to quantify the plasma concentrations of 24S-hydroxycholesterol in male and female volunteers.

  18. Urinary exposure marker discovery for toxicants using ultra-high pressure liquid chromatography coupled with Orbitrap high resolution mass spectrometry and three untargeted metabolomics approaches.

    Science.gov (United States)

    Hsu, Jen-Yi; Hsu, Jing-Fang; Chen, Yet-Ran; Shih, Chia-Lang; Hsu, Yi-Sheng; Chen, Yi-Jen; Tsai, Shu-Han; Liao, Pao-Chi

    2016-10-01

    Human biomonitoring is the assessment of actual internal contamination of chemicals by measuring exposure markers, chemicals or their metabolites, in human urine, blood, serum, and other body fluids. However, the metabolism of chemicals within an organism is extremely complex. Therefore, the identification of metabolites is often difficult and laborious. Several untargeted metabolomics methods have been developed to perform objective searching/filtering of accurate-mass-based LC-MS data to facilitate metabolite identification. In this study, three metabolomics data processing approaches were used for chemical exposure marker discovery in urine with an LTQ-Orbitrap high-resolution mass spectrometry (HRMS) dataset; di-isononyl phthalate (DINP) was used as an example. The data processing techniques included the SMAIT, mass defect filtering (MDF), and XCMS Online. Sixteen, 83, and 139 probable DINP metabolite signals were obtained using the SMAIT, MDF, and XCMS procedures, respectively. Fourteen probable metabolite signals mined simultaneously by the three metabolomics approaches were confirmed as DINP metabolites by structural information provided by LC-MS/MS. Among them, 13 probable metabolite signals were validated as exposure-related markers in a rat model. Six (m/z 319.155, 361.127, 373.126, 389.157, 437.112 and 443.130) of the 13 exposure-related DINP metabolite signals have not previously been reported in the literature. Our data indicate that SMAIT provided an efficient method to discover effectively and systematically urinary exposure markers of toxicant. The DINP metabolism information can provide valuable information for further investigations of DINP toxicity, toxicokinetics, exposure assessment, and human health effects. PMID:27639145

  19. Analytical capabilities of high performance liquid chromatography - Atmospheric pressure photoionization - Orbitrap mass spectrometry (HPLC-APPI-Orbitrap-MS) for the trace determination of novel and emerging flame retardants in fish.

    Science.gov (United States)

    Zacs, D; Bartkevics, V

    2015-10-22

    A new analytical method was established and validated for the analysis of 27 brominated flame retardants (BFRs), including so called "emerging" and "novel" BFRs (EBFRs and NBFRs) in fish samples. High performance liquid chromatography (HPLC) coupled to Orbitrap mass spectrometry (Orbitrap-MS) employing atmospheric pressure photoionization (APPI) interface operated in negative mode was used for the identification/quantitation of contaminants. HPLC-Orbitrap-MS analysis provided a fast separation of selected analytes within 14 min, thus demonstrating a high throughput processing of samples. The developed methodology was tested by intralaboratory validation in terms of recovery, repeatability, linear calibration ranges, instrumental and method limits of quantitation (i-LOQ and m-LOQ), and where possible, trueness was verified by analysis of certified reference materials (CRMs). Recoveries of analytes were between 80 and 119%, while the repeatability in terms of relative standard deviations (RSDs) was in the range from 1.2 to 15.5%. The measured values for both analyzed CRMs agreed with the provided consensus values, revealing the recovery of reference concentrations in 72-119% range. The elaborated method met the sensitivity criterion according to Commission Recommendation 2014/118/EU on monitoring of BFRs in food products for majority of the compounds. The concentrations of polybrominated diphenyl ethers (PBDEs) in real samples determined by HPLC-APPI-Orbitrap-MS method and validated gas chromatography-high-resolution mass spectrometry (GC-HRMS) method were found to be in a good agreement.

  20. Analytical capabilities of high performance liquid chromatography - Atmospheric pressure photoionization - Orbitrap mass spectrometry (HPLC-APPI-Orbitrap-MS) for the trace determination of novel and emerging flame retardants in fish.

    Science.gov (United States)

    Zacs, D; Bartkevics, V

    2015-10-22

    A new analytical method was established and validated for the analysis of 27 brominated flame retardants (BFRs), including so called "emerging" and "novel" BFRs (EBFRs and NBFRs) in fish samples. High performance liquid chromatography (HPLC) coupled to Orbitrap mass spectrometry (Orbitrap-MS) employing atmospheric pressure photoionization (APPI) interface operated in negative mode was used for the identification/quantitation of contaminants. HPLC-Orbitrap-MS analysis provided a fast separation of selected analytes within 14 min, thus demonstrating a high throughput processing of samples. The developed methodology was tested by intralaboratory validation in terms of recovery, repeatability, linear calibration ranges, instrumental and method limits of quantitation (i-LOQ and m-LOQ), and where possible, trueness was verified by analysis of certified reference materials (CRMs). Recoveries of analytes were between 80 and 119%, while the repeatability in terms of relative standard deviations (RSDs) was in the range from 1.2 to 15.5%. The measured values for both analyzed CRMs agreed with the provided consensus values, revealing the recovery of reference concentrations in 72-119% range. The elaborated method met the sensitivity criterion according to Commission Recommendation 2014/118/EU on monitoring of BFRs in food products for majority of the compounds. The concentrations of polybrominated diphenyl ethers (PBDEs) in real samples determined by HPLC-APPI-Orbitrap-MS method and validated gas chromatography-high-resolution mass spectrometry (GC-HRMS) method were found to be in a good agreement. PMID:26526911

  1. Towards Chip Scale Liquid Chromatography and High Throughput Immunosensing

    Energy Technology Data Exchange (ETDEWEB)

    Ni, J.

    2000-09-21

    This work describes several research projects aimed towards developing new instruments and novel methods for high throughput chemical and biological analysis. Approaches are taken in two directions. The first direction takes advantage of well-established semiconductor fabrication techniques and applies them to miniaturize instruments that are workhorses in analytical laboratories. Specifically, the first part of this work focused on the development of micropumps and microvalves for controlled fluid delivery. The mechanism of these micropumps and microvalves relies on the electrochemically-induced surface tension change at a mercury/electrolyte interface. A miniaturized flow injection analysis device was integrated and flow injection analyses were demonstrated. In the second part of this work, microfluidic chips were also designed, fabricated, and tested. Separations of two fluorescent dyes were demonstrated in microfabricated channels, based on an open-tubular liquid chromatography (OT LC) or an electrochemically-modulated liquid chromatography (EMLC) format. A reduction in instrument size can potentially increase analysis speed, and allow exceedingly small amounts of sample to be analyzed under diverse separation conditions. The second direction explores the surface enhanced Raman spectroscopy (SERS) as a signal transduction method for immunoassay analysis. It takes advantage of the improved detection sensitivity as a result of surface enhancement on colloidal gold, the narrow width of Raman band, and the stability of Raman scattering signals to distinguish several different species simultaneously without exploiting spatially-separated addresses on a biochip. By labeling gold nanoparticles with different Raman reporters in conjunction with different detection antibodies, a simultaneous detection of a dual-analyte immunoassay was demonstrated. Using this scheme for quantitative analysis was also studied and preliminary dose-response curves from an immunoassay of a

  2. Atmospheric pressure photoionisation : An ionization method for liquid chromatography-mass spectrometry

    NARCIS (Netherlands)

    Robb, DB; Covey, TR; Bruins, AP

    2000-01-01

    Atmospheric pressure photoionization (APPI) has been successfully demonstrated to provide high sensitivity to LC-MS analysis. A vacuum-ultraviolet lamp designed for photoionization detection in gas chromatography is used as a source of 10-eV photons. The mixture of samples and solvent eluting from a

  3. Identification of atranorin and related potential allergens in oakmoss absolute by high-performance liquid chromatography-tandem mass spectrometry using negative ion atmospheric pressure chemical ionization.

    Science.gov (United States)

    Hiserodt, R D; Swijter, D F; Mussinan, C J

    2000-08-01

    This paper describes the first high-performance liquid chromatographic-tandem mass spectrometric method for the identification of atranorin and related potential allergens in oakmoss absolute. Oakmoss absolute is ubiquitous in the fragrance industry and is a key component in many fine perfumes. However, oakmoss absolute causes an allergic response in some individuals. Research is focused toward establishing the identity of the compounds causing the allergic response so a quality controlled oakmoss with reduced allergenic potential can be prepared. Consequently a highly selective and specific analytical method is necessary to support this effort. This is not available with the existing HPLC methods using UV detection. PMID:10949477

  4. High Performance Liquid Chromatography at -196 °C.

    Science.gov (United States)

    Motono, Tomohiro; Kitagawa, Shinya; Ohtani, Hajime

    2016-07-01

    Ultralow temperature high-performance liquid chromatography (HPLC) was developed using a liquefied gas as the mobile phase. HPLC separation of low molecular weight alkanes at -196 °C with liquid nitrogen mobile phase was successfully achieved, whereas their GC separation at -196 °C using helium gas mobile phase failed to elute the analytes due to strong adsorption. Prior to the further study of HPLC at -196 °C, the effect of column temperature on the chromatographic behavior was investigated, and it was found that the retention of analytes drastically increased when the column temperature was over the boiling point of the mobile phase. As the study of retention control in HPLC at -196 °C, the mobile phases of nitrogen and methane mixtures were investigated. The addition of methane to the nitrogen mobile phase suppressed the retention of the analytes (tetra-deuterated methane, ethane, and propane), that is, the retention on HPLC at ultralow temperature could be controlled by the mobile phase composition, akin to the typical retention in HPLC. The selectivity toward the n- and iso-alkane in HPLC at -196 °C was altered compared with that in GC separation at room temperature. A significant enhancement of retention of alkanes compared with alkanes were observed in HPLC at -196 °C. PMID:27282809

  5. Optimized determination of polybrominated diphenyl ethers by ultrasound-assisted liquid-liquid extraction and high-performance liquid chromatography.

    Science.gov (United States)

    He, Kuang; Lv, YuanCai; Chen, YuanCai

    2014-10-01

    A method based on ultrasound-assisted liquid-liquid extraction and high-performance liquid chromatography has been optimized for the determination of six polybrominated diphenyl ether congeners. The optimal condition relevant to the extraction was first investigated, more than 98.7 ± 0.7% recovery was achieved with dichloromethane as extractant, 5 min extraction time, and three cycles of ultrasound-assisted liquid-liquid extraction. Then multiple function was employed to optimize polybrominated diphenyl ether detection conditions with overall resolution and chromatography signal area as the responses. The condition chosen in this experiment was methanol/water 93:7 v/v, flow rate 0.80 mL/min, column temperature 30.0°C. The optimized technique revealed good linearity (R(2) > 0.9962 over a concentration range of 1-100 μg/L) and repeatability (relative standard deviation ultrasound-assisted liquid-liquid extraction coupled with high-performance liquid chromatography was effective to identify and quantify the complex polybrominated diphenyl ethers in effluent samples. PMID:25142014

  6. 植物花青苷液质联用方法的分析鉴定%Golden rules of separation and characterization of plant anthocyanins by high pressure liquid chromatography-tandem mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    张洁; 李崇晖; 王亮生; 陈峰

    2013-01-01

      花青苷(anthocyanins)是植物中广泛存在的水溶性色素,在食品加工业中具有重要的地位。花青苷与人体健康密切相关,具有较强的抗氧化、抗炎症、抗微生物、抑制血小板凝聚和抗肿瘤等功效,已作为重要的功能因子而受到广泛的关注。花青苷成分的分析鉴定是花青苷生物活性研究的基础。然而,花青苷种类繁多,结构修饰多样,同时易受环境条件的影响,难以分离鉴定。高压液相色谱-二极管阵列检测-质谱联用技术(HPLC-DAD-MS)是花青苷分析最常规的手段。本文综述了如何利用HPLC-DAD-MS快速有效分离花青苷以及结构解析的一般规律及经验,以期为高附加值资源筛选以及花青苷构效关系的进一步揭示提供重要的化学基础。%  Anthocyanins are important water-soluble pigments, which have significant influence in food processing industry. Anthocyanins have anti-oxidant, anti-inflammatory, anti-antimicrobial, inhibition of platelet aggregation and anticancer activity, and have been the focus as important functional ingredients. Separation and identification of anthocyanins are the base for studying their bioactive effects. However, the complexity and va-riety of anthocyanins make it difficult to characterize the composition of anthocyanins. High pressure liquid chromatography (HPLC) coupled with mass spectrometry has become the standard and most powerful method for routine anthocyanin analysis. This paper reviewed the golden rules for separation and identification of anthocya-nins by high pressure liquid chromatography-tandem mass spectrometry (HPLC-DAD-MS), which might provide the chemical evidence for clarification of structure-activity relationship and screening for high value-added re-sources.

  7. Sheath liquid effects in capillary high-performance liquid chromatography-electrospray mass spectrometry of oligonucleotides.

    Science.gov (United States)

    Huber, C G; Krajete, A

    2000-02-18

    Fused-silica capillary columns of 200 microm inner diameter were packed with micropellicular, octadecylated, 2.3 microm poly(styrene-divinylbenzene) particles and applied to the separation of oligonucleotides by ion-pair reversed-phase high-performance liquid chromatography. Oligonucleotides were eluted at 50 degrees C with gradients of 3-13% acetonitrile in 50 mM triethylammonium bicarbonate. Addition of sheath liquid to the column effluent allowed the detection of oligonucleotides by electrospray ionization mass spectrometry using full-scan data acquisition with a detectability comparable to that obtained with UV detection. The signal-to-noise ratios with different sheath liquids increased in the order isopropanolliquid was found to influence the charge state distribution of oligonucleotides longer than 20 nucleotide units whereas no significant effect was observed with shorter oligonucleotides. Organic acids and bases in the sheath liquid generally deteriorated the signal-to-noise ratios in the chromatograms and mass spectra mainly because of increased background noise. Only a few charge states were observed in the mass spectra of oligonucleotides because of charge state reduction due to the presence of carbonic acid in the eluent. With triethylammonium hydrogencarbonate as chromatographic eluent and acetonitrile as sheath liquid, very few cation adducts of oligonucleotides were observed in the mass spectra. However, the presence of small amounts of monopotassium adducts enabled the calculation of the charge state of multiply charged ions. With acetonitrile as sheath liquid, 710 amol of a 16-mer oligonucleotide were detected using selected ion monitoring data acquisition with a signal-to-noise ratio of 3:1. Finally, capillary ion-pair reversed-phase high-performance liquid chromatography-electrospray ionization mass spectrometry was

  8. Distribution of C16:0, C18:0, C24:1, and C24:0 sulfatides in central nervous system lipid rafts by quantitative ultra-high-pressure liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Moyano, Ana Lis; Li, Guannan; Lopez-Rosas, Aurora; Månsson, Jan-Eric; van Breemen, Richard B; Givogri, Maria Irene

    2014-12-15

    Sulfated galactosylceramides (sulfatides) are glycosphingolipids associated with cholesterol- and sphingolipid-enriched membrane microdomains (lipid rafts) and are highly expressed in brain tissue. Although it is known that sulfatide species show heterogeneity in their fatty acid acyl group composition throughout brain development, their lipid raft distribution and biological relevance is poorly understood. We validated a fast and sensitive ultra-high-pressure liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method to measure developmentally regulated sulfatide species (C16:0, C18:0, C24:1, and C24:0) in central nervous system (CNS) lipid rafts isolated without using detergent. Our UHPLC-MS/MS assay showed good accuracy and precision with a linear range of 5 to 1,000 nM for C18:0 and C24:1 sulfatides and 10 to 1,000 nM for C16:0 and C24:0 sulfatides. We applied this quantitative analysis to detergent-free lipid rafts isolated from wild-type mice and arylsulfatase A-deficient (ASA knockout) mice that accumulate sulfatides. All four sulfatide species were more abundant in raft membranes than in non-raft membranes, with a significant increase in lipid rafts isolated from ASA knockout mice. This is the first description of an analytical method to study these sulfatide species in raft and non-raft membranes and has the potential to be applied to preparations from other tissues.

  9. Microfabricated electrochemical detector for high-performance liquid chromatography.

    Science.gov (United States)

    Ogburn, Evan T; Dziewatkoski, Michael; Moles, Don; Johnson, Jay M; Heineman, William R

    2011-09-15

    A microfabricated electrochemical cell has been developed as a disposable detector for flow injection analysis (FIA) and high-performance liquid chromatography (HPLC). The simplicity of the fabrication process allows this detector to be used as a low-cost, disposable device that can be replaced easily if its performance degrades rather than disassembling the detector and polishing the electrode surface, which is the usual procedure. The detector consists of thin film-metal electrodes-platinum working electrode, platinum auxiliary electrode, and silver/silver chloride coated on Pt reference electrode-deposited on a polyimide substrate with a locking layer of chromium in between. A microfluidic cover made of polyimide directs the solution flow across the electrodes. The detector was evaluated with FIA of ferrocyanide and HPLC of ascorbic acid and acetaminophen and a mixture of two pharmaceutical compounds-dextrorphan and levallorphan-with acetaminophen internal standard. The HPLC calibration curves showed good linearity (R(2) > 0.99). Limits of detection were 1 nM for acetaminophen, 1 nM for ascorbic acid, 50 nM for dextrorphan, and 80 nM for levallorphan. When detected with a commercial detector dextrorphan and levallorphan had lower limits of detection, 3 and 5 nM, respectively. Chromatograms of the mixture were comparable to those obtained with a commercial detector. The detector could be used continuously for about 48 h with FIA and about 10-20 h with HPLC after which performance gradually degraded as the AgCl on the reference electrode dissolved causing loss of potential control. PMID:21598939

  10. A Generalized Equation of State for High-Pressure Liquids

    Institute of Scientific and Technical Information of China (English)

    LIANG Yan-bo; TONG Jing-shan

    2005-01-01

    An equation of state (EOS) for high-pressure liquids, I.e., Tait EOS, is deduced according to isothermal compressibility KT=-1/V·((а)V/(а)p)T·.Based on the equation, a generalized EOS for high pressure-liquids is established by using the reduced state principle and introducing a characteristic parameter-configuration factorξ.Reasonably satisfactory P-V-T data for many organic compounds, including some polar components, were calculated by using the equation.

  11. Comparison of microbial communities in Lake Tahoe surface sample with Tonga Trench water column samples using High Pressure Liquid Chromatography - Electrospray Ionization - Mass Spectroscopy (HPLC - ESI - MS) and Global Natural Products Social Molecular Network (GNPS)

    Science.gov (United States)

    Belmonte, M. A.

    2015-12-01

    Intact polar lipids (IPLs) are lipids composed of a head group, a glycerol, and a fatty acid chain that make up the lipid bilayer of cell membranes in living cells; and the varying head groups can be indicative of the type of microbes present in the environment (Van Mooy 2010). So by distinguishing and identifying the IPL distribution in an environment one can make inferences about the microbial communities in the said environment. In this study, we used High Pressure Liquid Chromatography-Electrospray Ionization- Mass Spectroscopy (HPLC-ESI-MS) and Global Natural Products Social Molecular Networking (GNPS) to compare the IPL distributions of two oligotrophic environments: surface waters of Lake Tahoe in the Sierra Nevada Mountains, and the water column of the Tonga Trench in the South Pacific. We hypothesized that the similar nutrient dynamics of the two oligotrophic environments would result in similar eukaryotic and prokaryotic communities, which would be reflected in the IPL composition of suspended particulate organic matter (POM). For simplicity we focused on the classes of IPLs most commonly observed in the marine environment: phosphotidylglycerol (PG), phosphotidylethanolamine (PE), diacylglyceryl-trimethyl-homoserine (DGTS), diacylglyceryl-hydroxymethyl-trimethylalanine (DGTA), sulfoquinovosyldiacylglycerol (SQDG), monoglycosyldiacylglycerol (MGDG) and diglycosyldiacylglycerol (DGDG). Our results showed that all of the marine IPLs of interest were present in Lake Tahoe which confirms that there are many of the same microbial communities in the fresh waters of Lake Tahoe and the salt waters Tonga Trench.

  12. Fast, rugged and sensitive ultra high pressure liquid chromatography tandem mass spectrometry method for analysis of cyanotoxins in raw water and drinking water--First findings of anatoxins, cylindrospermopsins and microcystin variants in Swedish source waters and infiltration ponds.

    Science.gov (United States)

    Pekar, Heidi; Westerberg, Erik; Bruno, Oscar; Lääne, Ants; Persson, Kenneth M; Sundström, L Fredrik; Thim, Anna-Maria

    2016-01-15

    Freshwater blooms of cyanobacteria (blue-green algae) in source waters are generally composed of several different strains with the capability to produce a variety of toxins. The major exposure routes for humans are direct contact with recreational waters and ingestion of drinking water not efficiently treated. The ultra high pressure liquid chromatography tandem mass spectrometry based analytical method presented here allows simultaneous analysis of 22 cyanotoxins from different toxin groups, including anatoxins, cylindrospermopsins, nodularin and microcystins in raw water and drinking water. The use of reference standards enables correct identification of toxins as well as precision of the quantification and due to matrix effects, recovery correction is required. The multi-toxin group method presented here, does not compromise sensitivity, despite the large number of analytes. The limit of quantification was set to 0.1 μg/L for 75% of the cyanotoxins in drinking water and 0.5 μg/L for all cyanotoxins in raw water, which is compliant with the WHO guidance value for microcystin-LR. The matrix effects experienced during analysis were reasonable for most analytes, considering the large volume injected into the mass spectrometer. The time of analysis, including lysing of cell bound toxins, is less than three hours. Furthermore, the method was tested in Swedish source waters and infiltration ponds resulting in evidence of presence of anatoxin, homo-anatoxin, cylindrospermopsin and several variants of microcystins for the first time in Sweden, proving its usefulness.

  13. A comparative study on analytical method of total alkaloids from cortex Phellodendri amurens by reversed phase high performance liquid chromatography (RP-HPLC and pressurized capillary electrochromatography (pCEC

    Directory of Open Access Journals (Sweden)

    Bo Yang

    2011-02-01

    Full Text Available A pressurized capillary electrochromatography (pCEC method with post-column detection cell has been developed for the analysis of total alkaloids of cortex Phellodendron amurense Rupr., Rutaceae. The separation of total alkaloids (berberine, palmatine, oatrorrhizine, magnoflorine, phellodendrine, candicine, menisperine was optimized by compositions of the mobile phase, ionic strength of buffers, pH value, and applied voltage. Separation of total alkaloids was achieved within 11 min by using a mobile phase of Na2HPO4-citric acid solution-acetonitrile (pH 4.00; 3 mM (60:40, v/v and applying a voltage of -10 kV. This method showed satisfactory retention times and peak shapes. Meanwhile, a reversed phase high performance liquid chromatography (RP-HPLC has also been established for the separation of total alkaloids extracted from cortex Phellodendri amurens. Baseline separation of total alkaloids was achieved within 25 min by using a mobile phase of acetonitrile-0.1% phosphoric acid with 0.1 g sodium dodecanesulphonate per 100 mL (35:65, v/v. Compared to conventional RP-HPLC, pCEC led to higher column efficiency, less consumption of reagent, and shorter analysis time.

  14. Systematic Analysis of Absorbed Anti-Inflammatory Constituents and Metabolites of Sarcandra glabra in Rat Plasma Using Ultra-High-Pressure Liquid Chromatography Coupled with Linear Trap Quadrupole Orbitrap Mass Spectrometry.

    Directory of Open Access Journals (Sweden)

    Xiong Li

    Full Text Available Ultra-high-pressure liquid chromatography (UHPLC was coupled with linear ion trap quadrupole Orbitrap mass spectrometry (LTQ-Orbitrap and was used for the first time to systematically analyze the absorbed components and metabolites in rat plasma after oral administration of the water extract of Sarcandra glabra. This extract is a well-known Chinese herbal medicine for the treatment of inflammation and immunity related diseases. The anti-inflammatory activities of the absorbed components were evaluated by measuring nitric oxide (NO production and proinflammatory genes expression in lipopolysaccharide (LPS-stimulated murine RAW 264.7 macrophages. As a result, 54 components in Sarcandra glabra were detected in dosed rat plasma, and 36 of them were positively identified. Moreover, 23 metabolites were characterized and their originations were traced. Furthermore, 20 of the 24 studied components showed anti-inflammatory activities. These results provide evidence that this method efficiency detected constituents in plasma based on the anti-inflammatory mechanism of multiple components and would be a useful technique for screening multiple targets for natural medicine research.

  15. Pressurized liquid extraction for the determination of cannabinoids and metabolites in hair: Detection of cut-off values by high performance liquid chromatography-high resolution tandem mass spectrometry.

    Science.gov (United States)

    Montesano, Camilla; Simeoni, Maria Chiara; Vannutelli, Gabriele; Gregori, Adolfo; Ripani, Luigi; Sergi, Manuel; Compagnone, Dario; Curini, Roberta

    2015-08-01

    Hair analysis has become a routine procedure in most forensic laboratories since this alternative matrix presents clear advantages over classical matrices; particularly wider time window, non-invasive sampling and good stability of the analytes over time. There are, however, some major challenges for the analysis of cannabinoids in hair, mainly related to the low concentrations of 11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol (THC-COOH), that is the major metabolite. In this study a fast, accurate and sensitive method for the determination of cannabinol, cannabidiol, THC and THC-COOH in hair has been developed. The extraction of analytes from hair (50mg) is based on an automated pressurized liquid extraction (PLE) using water modified with the surfactant sodium dodecyl sulphate as eluent phase. PLE extract is then cleaned up by SPE using polymeric reversed phase cartridges Strata XL before the injection in the HPLC-HRMS/MS system. Chromatographic conditions obtained with a fused-core column allowed a good separation of the analytes in less than 4min. The whole procedure has been validated according to SWGTOX guidelines. The LLOQs obtained for THC-COOH and the other analytes were respectively 0.1 and 2pg/mg. To the best of our knowledge, this is the first LC-MS/MS based method that allows the detection of THC-COOH in hair at values lower than the cut-off. PMID:26118805

  16. Application of High Performance Liquid Chromatography to Separation of Novel Chiral Tetrahedral Heterometal Clusters

    Institute of Scientific and Technical Information of China (English)

    Xin Yi ZHU; Wei Qiang ZHANG; Yu Hua ZHANG; Li Ren CHEN; Yong Min LI

    2003-01-01

    A series of novel chiral tetrahedral heterometal clusters have firstly been separated oncellulose tris-(3,5-dimethylphenylcarbamate) stationary phase by high performance liquid chrom-atography, using hexane as the mobile phase with various alcohols as modifiers.

  17. Achieving quasi-adiabatic thermal environment to maximize resolution power in very high-pressure liquid chromatography: Theory, models, and experiments.

    Science.gov (United States)

    Gritti, Fabrice; Gilar, Martin; Jarrell, Joseph A

    2016-04-29

    A cylindrical vacuum chamber (inner diameter 5 cm) housing a narrow-bore 2.1 mm×100 mm column packed with 1.8 μm HSS-T3 fully porous particles was built in order to isolate thermally the chromatographic column from the external air environment. Consistent with statistical physics and the mean free path of air molecules, the experimental results show that natural air convection and conduction are fully eliminated for housing air pressures smaller than 10(-4) Torr. Heat radiation is minimized by wrapping up the column with low-emissivity aluminum-tape (emissivity coefficient ϵ=0.03 vs. 0.28 for polished stainless steel 316). Overall, the heat flux at the column wall is reduced by 96% with respect to standard still-air ovens. From a practical viewpoint, the efficiency of the column run at a flow rate of 0.6 mL/min at a constant 13,000 psi pressure drop (the viscous heat power is around 9 W/m) is improved by up to 35% irrespective of the analyte retention. Models of heat and mass transfer reveal that (1) the amplitude of the radial temperature gradient is significantly reduced from 0.30 to 0.01 K and (2) the observed improvement in resolution power stems from a more uniform distribution of the flow velocity across the column diameter. The eddy dispersion term in the van Deemter equation is reduced by 0.8±0.1 reduced plate height unit, a significant gain in column performance.

  18. Extraction of 3,4,4'-Trichlorocarbanilide from Rat Fecal Samples for Determination by High Pressure Liquid Chromatography-Tandem Mass Spectrometry.

    Science.gov (United States)

    Kennedy, Rebekah C; Fling, Russell R; Terry, Paul D; Menn, Fu-Min; Chen, Jiangang; Borman, Christopher J

    2015-07-01

    Triclocarban (3,4,4'-Trichlorocarbanilide; TCC) in the environment has been well documented. Methods have been developed to monitor TCC levels from various matrices including water, sediment, biosolids, plants, blood and urine; however, no method has been developed to document the concentration of TCC in fecal content after oral exposure in animal studies. In the present study, we developed and validated a method that uses liquid extraction coupled with HPLC-MS/MS determination to measure TCC in feces. The limit of detection and limit of quantitation in control rats without TCC exposure was 69.0 ng/g and 92.9 ng/g of feces, respectively. The base levels of TCC in feces were lower than LOD. At 12 days of treatment, the fecal TCC concentration increased to 2220 µg/g among 0.2% w/w exposed animals. The concentration in fecal samples decreased over the washout period in 0.2% w/w treated animals to 0.399 µ/g feces after exposure was removed for 28 days. This method required a small amount of sample (0.1 g) with simple sample preparation. Given its sensitivity and efficiency, this method may be useful for monitoring TCC exposure in toxicological studies of animals. PMID:26184276

  19. Equation of state of liquid Indium under high pressure

    International Nuclear Information System (INIS)

    We apply an equation of state of a power law form to liquid Indium to study its thermodynamic properties under high temperature and high pressure. Molar volume of molten indium is calculated along the isothermal line at 710K within good precision as compared with the experimental data in an externally heated diamond anvil cell. Bulk modulus, thermal expansion and internal pressure are obtained for isothermal compression. Other thermodynamic properties are also calculated along the fitted high pressure melting line. While our results suggest that the power law form may be a better choice for the equation of state of liquids, these detailed predictions are yet to be confirmed by further experiment

  20. Equation of state of liquid Indium under high pressure

    Science.gov (United States)

    Li, Huaming; Sun, Yongli; Li, Mo

    2015-09-01

    We apply an equation of state of a power law form to liquid Indium to study its thermodynamic properties under high temperature and high pressure. Molar volume of molten indium is calculated along the isothermal line at 710K within good precision as compared with the experimental data in an externally heated diamond anvil cell. Bulk modulus, thermal expansion and internal pressure are obtained for isothermal compression. Other thermodynamic properties are also calculated along the fitted high pressure melting line. While our results suggest that the power law form may be a better choice for the equation of state of liquids, these detailed predictions are yet to be confirmed by further experiment.

  1. Equation of state of liquid Indium under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Li, Huaming, E-mail: huamingli@gatech.edu, E-mail: mo.li@gatech.edu; Li, Mo, E-mail: huamingli@gatech.edu, E-mail: mo.li@gatech.edu [College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024 (China); School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Sun, Yongli [College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024 (China)

    2015-09-15

    We apply an equation of state of a power law form to liquid Indium to study its thermodynamic properties under high temperature and high pressure. Molar volume of molten indium is calculated along the isothermal line at 710K within good precision as compared with the experimental data in an externally heated diamond anvil cell. Bulk modulus, thermal expansion and internal pressure are obtained for isothermal compression. Other thermodynamic properties are also calculated along the fitted high pressure melting line. While our results suggest that the power law form may be a better choice for the equation of state of liquids, these detailed predictions are yet to be confirmed by further experiment.

  2. Determination of the mycotoxin moniliformin in cultures of Fusarium subglutinans and in naturally contaminated maize by high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry.

    Science.gov (United States)

    Sewram, V; Nieuwoudt, T W; Marasas, W F; Shephard, G S; Ritieni, A

    1999-07-01

    A LC-MS method employing triethylamine as ion-pairing reagent for the determination of moniliformin in culture material and naturally contaminated maize samples is described. Mass spectrometric detection of moniliformin was accomplished following atmospheric pressure chemical ionization to yield the deprotonated molecular ion [M-H]- at m/z 97. The moniliformin response was found to be linear over the injected range 10 ng to 700 ng and a detection limit of 10 ng was attainable at a signal-to-noise (S/N) ratio of 4. Five South African strains of Fusarium subglutinans were grown on maize kernels and moniliformin extracted with an acetonitrile-water (95:5) mixture. Following sample clean up with reversed-phase (C18) solid-phase extraction cartridges, the extracts were subjected to LC-MS analysis. Triethylamine was used as an ion-pair reagent and found to improve the retention characteristics of moniliformin without any detrimental effects to the instrument. Moniliformin concentrations ranged between 130 mg/kg and 1460 mg/kg culture. Application of this method to naturally contaminated maize samples from Transkei showed that it was capable of measuring moniliformin levels down to 10 micrograms/kg in selected moldy maize cobs. This is the first report on the application of LC-MS to the analysis of moniliformin in cultures of F. subglutinans and in naturally contaminated maize. PMID:10427758

  3. Determination of sulfonamides in butter samples by ionic liquid magnetic bar liquid-phase microextraction high-performance liquid chromatography.

    Science.gov (United States)

    Wu, Lijie; Song, Ying; Hu, Mingzhu; Xu, Xu; Zhang, Hanqi; Yu, Aimin; Ma, Qiang; Wang, Ziming

    2015-01-01

    A novel, simple, and environmentally friendly pretreatment method, ionic liquid magnetic bar liquid-phase microextraction, was developed for the determination of sulfonamides in butter samples by high-performance liquid chromatography. The ionic liquid magnetic bar was prepared by inserting a stainless steel wire into the hollow of a hollow fiber and immobilizing ionic liquid in the micropores of the hollow fiber. In the extraction process, the ionic liquid magnetic bars were used to stir the mixture of sample and extraction solvent and enrich the sulfonamides in the mixture. After extraction, the analyte-adsorbed ionic liquid magnetic bars were readily isolated with a magnet from the extraction system. It is notable that the present method was environmentally friendly since water and only several microliters of ionic liquid were used in the whole extraction process. Several parameters affecting the extraction efficiency were investigated and optimized, including the type of ionic liquid, sample-to-extraction solvent ratio, the number of ionic liquid magnetic bars, extraction temperature, extraction time, salt concentration, stirring speed, pH of the extraction solvent, and desorption conditions. The recoveries were in the range of 73.25-103.85 % and the relative standard deviations were lower than 6.84 %. The experiment results indicated that the present method was effective for the extraction of sulfonamides in high-fat content samples.

  4. Accurate quantitation of pentaerythritol tetranitrate and its degradation products using liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry

    NARCIS (Netherlands)

    Brust, H.; Asten, A. van; Koeberg, M.; Dalmolen, J.; Heijden, A.E.D.M. van der; Schoenmakers, P.

    2014-01-01

    After an explosion of pentaerythritol tetranitrate (PETN), its degradation products pentaerythritol trinitrate (PETriN), dinitrate (PEDiN) and mononitrate (PEMN) were detected using liquid chromatography-atmospheric-pressure chemical-ionization-mass spectrometry (LC-APCI-MS). Discrimination between

  5. Determination of kava lactones in food supplements by liquid chromatography-atmospheric pressure chemical ionisation tandem mass spectrometry

    NARCIS (Netherlands)

    Bobeldijk, I.; Boonzaaijer, G.; Spies-Faber, E.J.; Vaes, W.H.J.

    2005-01-01

    Reversed-phase liquid chromatography and detection with atmospheric pressure chemical ionisation tandem mass spectrometry was used for the determination of kava extracts in herbal mixtures. One percent of kava extract can be detected, corresponding to approximately 0.05-0.2 mg/g of the individual ka

  6. Identification of photodegradation product of amisulpride by ultra-high-pressure liquid chromatography-DAD/ESI-quadrupole time-of-flight-mass spectrometry.

    Science.gov (United States)

    Skibiński, Robert

    2011-12-15

    Photostability of amisulpride under UVA irradiation in methanol solution was investigated and structural elucidation of its photodegradation products was performed. For the purpose of the quantitative and qualitative analysis of amisulpride and the stress degradation products elucidation, the reversed phase UHPLC-DAD system coupled with accurate mass hybrid ESI-Q-TOF mass spectrometer was used. During one run (10 min) with the use of auto MS/MS mode all essential data for the determination of photodegradation kinetics and for the structural formulas elucidation of the products was collected. Four degradation products were found and their masses with high accuracy (0.53-3.05 ppm) and formulas were obtained--258.0666 (C(10)H(14)N(2)O(4)S), 367.1564 (C(17)H(25)N(3)O(4)S), 341.1412 (C(15)H(23)N(3)O(4)S) and 385.1665 (C(17)H(27)N(3)O(5)S). For all the analyzed compounds MS/MS fragmentation spectra were obtained (collision energy 19.8-26.1 V) allowing structural elucidation of unknown degradation products and indicating photodegradation pathways of amisulpride. UHPLC-DAD/ESI-Q-TOF system was found to be a powerful analytical tool for the fast and accurate stability analysis of pharmaceutical substances.

  7. Comparison between high performance liquid chromatography and high performance thin layer chromatography determination of Diosgenin from fenugreek seeds

    Directory of Open Access Journals (Sweden)

    Dheeraj H Nagore

    2012-01-01

    Full Text Available Background: Fenugreek is used in the treatment of many diseases as reported in Ayurveda. The chemical like Diosgenin is one of the important chemicals of fenugreek. Aim: To develop simple, rapid, accurate methods for estimation of Diosgenin from fenugreek using high performance thin layer chromatography (HPTLC and high performance liquid chromatography (HPLC. Materials and Methods: The two chromatographic methods, HPTLC and HPLC, were developed and compared to quantitative determination of Diosgenin in fenugreek seed extract. For both the analyses, the scanning wavelength was set at 205 nm. The Diosgenin content of seven different extracts collected from different locations was compared by HPLC and HPTLC. Statistical Analysis: The relative standard deviation and correlation coefficient (r2 were calculated by standard Formulae. Results: The comparison was done in HPTLC and HPLC results and all the results are found to be within the limits and showed no significant difference. Conclusion: Both the methods were accurate and specific for the analysis of Diosgenin.

  8. Equation of state of liquid Indium under high pressure

    OpenAIRE

    Huaming Li; Yongli Sun; Mo Li

    2015-01-01

    We apply an equation of state of a power law form to liquid Indium to study its thermodynamic properties under high temperature and high pressure. Molar volume of molten indium is calculated along the isothermal line at 710K within good precision as compared with the experimental data in an externally heated diamond anvil cell. Bulk modulus, thermal expansion and internal pressure are obtained for isothermal compression. Other thermodynamic properties are also calculated along the fitted high...

  9. Resolution of RNA using high-performance liquid chromatography

    NARCIS (Netherlands)

    Mclaughlin, L.W.; Bischoff, Rainer

    1987-01-01

    High-performance liquid chromatographic techniques can be very effective for the resolution and isolation of nucleic acids. The characteristic ionic (phosphodiesters) and hydrophobic (nucleobases) properties of RNAs can be exploited for their separation. In this respect anion-exchange and reversed-p

  10. Precise Measurement of Phenylalanine δ15N Values via Elemental Analysis-Isotope Ratio Mass Spectrometry Following Purification with High-Pressure Liquid Chromatography: A New Tool for Fine-Scale Paleo-Nitrogen Cycle Reconstructions

    Science.gov (United States)

    Broek, T.; Walker, B. D.; Batista, F. C.; Andreasen, D.; Hill, T. M.; Guilderson, T. P.; McCarthy, M.

    2012-12-01

    Compound specific isotope analysis of individual amino acids (CSI-AA) in organic paleoarchives is emerging as a powerful tool for reconstructing the paleo-nitrogen (N) cycle. Because the δ15N of phenylalanine (Phe) remains almost unchanged with diagenesis or trophic transfer it has been demonstrated to be the most promising AA proxy for the δ15N of primary production. However, the precise measurement of AA δ15N values is currently limited by the standard gas chromatography-isotope ratio mass spectrometer (GC-IRMS) approach. The key problem with this approach is that GC-IRMS δ15N precision (±1‰) is almost an order of magnitude lower than typical bulk δ15N measurements (±0.1‰), posing a significant problem for assessing fine scale changes within paleo-climate records. Additionally, required instrumentation is both expensive, and not widely available. Here we present an offline approach in which Phe is purified via high-pressure liquid chromatography (HPLC), using an analytical scale, mixed-phase column and automated fraction collection. δ13C and δ15N values of the fractions are then determined via standard elemental analysis-isotope ratio mass spectrometry (EA-IRMS). We evaluate the precision of this HPLC-EA-IRMS method vs. traditional GC-IRMS for Phe δ15N values of isotopic AA standards and various proteinaceous marine samples (marine coral, sediment, and cyanobacteria). Typical HPLC-EA-IRMS δ15N precision is ±0.1‰ for isotopic AA standards and ±0.5‰ for marine coral, sediment, and cyanobacteria samples compared to ±0.5‰ and ±1.0‰ for AA standards and samples analyzed by GC-IRMS. In order to demonstrate the viability of our approach, we present a comparison of a Phe δ15N record produced from a deep-sea bamboo coral specimen from Monterey Bay, CA, using our offline HPLC-EA-IRMS method vs. standard GC-IRMS. Each method produced equivalent Phe δ15N values within error, however, the HPLC-EA-IRMS method produced Phe δ15N values with over

  11. Part-per-trillion level determination of antifouling pesticides and their byproducts in seawater samples by off-line solid-phase extraction followed by high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry.

    Science.gov (United States)

    Martínez, K; Ferrer, I; Barceló, D

    2000-05-19

    A new method for the simultaneous determination of antifouling pesticides and some of their byproducts such as dichlofluanid, diuron and its byproducts [demethyldiuron and 1-(3,4-dichlorophenyl)urea], (2-thiocyanomethylthio)ben: zothiazole, chlorothalonil, Sea-nine 211, Irgarol 1051 and one of its byproducts (2-methylthio-4-tert.-butylamino-s-triazine) in seawater was developed. The extraction of these compounds from the filtered seawater samples was performed off-line with different solid-phase extraction sorbents using (I) a 500 mg graphitized carbon black cartridge (ENVI-Carb) and (II) 200 mg polymeric cartridges (LiChrolut EN and Isolute ENV+) and passing 500 ml of the sample through these cartridges. The detection was carried out by reversed-phase high-performance liquid chromatography coupled with atmospheric pressure chemical ionization mass spectrometry both in the negative and positive ion modes. The recovery ranged from 76 to 96% for the whole antifouling group with the ENVI-Carb cartridges and the detection limit was at the part-per-trillion level except for TCMTB. The method utilizing the polymeric cartridge proved to be very useful, time saving and with good recoveries when only Irgarol and its byproduct, Sea-nine 211 and diuron and its byproducts, have to be analyzed. The different cartridges were applied to the analysis of these pesticides in different marinas of the Catalan coast; diuron, dichlofluanid, Sea-nine 211, Irgarol as well as demethyldiuron and the Irgarol byproduct being the must ubiquitous pollutants. Maximum concentration levels were 2-3.5 microg/l of diuron and Sea-nine 211, respectively. PMID:10870693

  12. Differentiation of coloured inks of inkjet printer cartridges by thin layer chromatography and high performance liquid chromatography.

    Science.gov (United States)

    Poon, N L; Ho, S S H; Li, C K

    2005-01-01

    Document examiners are frequently asked to determine whether or not a colour printout has originated from a particular inkjet printer. The printer can rarely be identified unless some unique defects or irregularities of the printer are present on the printout. However, it is possible to decipher the make and/or model of the printer by comparing the ink-profile of the questioned printout with that of a seized inkjet printer cartridge or from one in a database. This paper presents an overview of a systematic approach to characterising and discriminating the inks of different inkjet printer cartridges using thin layer chromatography (TLC) and high pressure liquid chromatography (HPLC) with multi-wavelength ultra-violet/visible (UV/Vis) detection. Ink samples from 23 different inkjet printer cartridges (including originals and substitutes) of different brands and colour printouts, printed by known printers were examined with newly developed chromatographic methods. Subsequently, a database of the ink-profiles was generated. The methods provide a useful tool for discriminating coloured inks in inkjet printer cartridges of different brands.

  13. HIGH PERFORMANCE LIQUID CHROMATOGRAPHY DETECTORS – A REVIEW

    Directory of Open Access Journals (Sweden)

    Kaushal Ramni

    2011-05-01

    Full Text Available HPLC is the most versatile and widely used elution chromatography. The technique is used to resolve and determine species in a variety of organic, inorganic, biological, ionic and polymeric materials. Detector is the heart of an instrument and efficiency of system is dependent upon detecting techniques. Many types of HPLC detectors exist, each of which has some valuable performance feature such as refractive index detector, ultraviolet detector, fluorescent detector, electrochemical detector, electric conductivity detector, liquid light scattering detector, evaporative light scattering detector. Due to strong requirement for improvements in sensitivity, selectivity and other performance characteristics of the detector recent developments in conventional techniques and some other new technologies have been adopted such as laser light scattering detector, charged aerosol detector, nano quantity aerosol detector, chiral detector and pulsed amperometric detector. These detectors provide accurate concentration analysis, excellent sensitivity, wide dynamic range, consistent response and broad applicability of the drug components. Working of these detectors involve different principles such as optical techniques, aerosol based techniques, refractive methods, light scattering principle, amperometric and fluorescence. The present review enlightens both conventional and advanced techniques and compares their capabilities of analyzing drug components and need for new techniques for better and wide range of applicability.

  14. Analysis of carotenoid and porphyrin pigments of geochemical interest by high-performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Hajibrahim, S.K. (Univ. of Bristol, Eng.); Tibbetts, P.J.C.; Watts, C.D.; Maxwell, J.R.; Eglinton, G.; Colin, H.; Guiochon, G.

    1978-04-01

    High-performance liquid chromatography (HPLC) is shown to be a powerful tool in the analysis of carotenoid and porphyrin pigments. Columns packed with 5-..mu..m irregular silica gel particles by a high density and high constant pressure method allow efficient separation of mixtures of total nonsaponifiable carotenoids from recent sedimentary situations. Good reproducibility of retention times (within 2%) is achieved in the gradient elution mode. However, attention must be paid to reequilibration of the column after each injection by washing with the less polar solvent for a minimum of 15 min (for carotenoids) or of 30 min (for porphyrins). HPLC appears to be useful in ''fingerprinting'' petroporphyrin distributions in crude oil.

  15. High-performance liquid chromatography analysis methods developed for quantifying enzymatic esterification of flavonoids in ionic liquids

    DEFF Research Database (Denmark)

    Lue, Bena-Marie; Guo, Zheng; Xu, X.B.

    2008-01-01

    Methods using reversed-phase high-performance liquid chromatography (RP-HPLC) with ELSD were investigated to quantify enzymatic reactions of flavonoids with fatty acids in the presence of diverse room temperature ionic liquids (RTILs). A buffered salt (preferably triethylamine-acetate) was found...

  16. The Application of High Performance Liquid Chromatography in the Analysis of Trace Rare Earth

    Institute of Scientific and Technical Information of China (English)

    WANG; Xiu-feng; DING; You-qian

    2012-01-01

    <正>Rare earth elements are very important in the field of radioanalytical chemistry, for it must be separated and determined in the measurements of burn-up and fission yield. High performance liquid chromatography has become a main method in the separation of rare earth elements due to its obvious advantages, this is, high speed of analysis, high efficiency and easy automation. The ion exchange chromatography is the main means to separate rare earth elements, especially the cation exchange

  17. Ultrahigh-pressure liquid chromatography of isoflavones and phenolic acids on different stationary phases.

    Science.gov (United States)

    Klejdus, B; Vacek, J; Lojková, L; Benesová, L; Kubán, V

    2008-06-27

    Complete separation of aglycones and glucosides of selected isoflavones (genistin, genistein, daidzin, daidzein, glycitin, glycitein, ononin, sissotrin, formononetin, and biochanin A) was possible in 1.5 min using an ultrahigh-pressure liquid chromatography (U-HPLC) on a different particular chemically modified stationary phases with a particle size under 2 microm. In addition, selected separation conditions for simultaneous determination of isoflavones together with a group of phenolic acids (gallic, protocatechuic, p-hydroxybenzoic, vanillic, caffeic, syringic, p-coumaric, ferulic, and sinapic acid) allowed separation of all 19 compounds in 1.9 min. Separations were conducted on a non-polar reversed phase (C(18)) and also on more polar phases with cyanopropyl or phenyl groups using a gradient elution with a mobile phase consisting of 0.3% aqueous acetic acid and methanol. Chromatographic peaks were characterised using parameters such as resolution, symmetry, selectivity, etc. Individual substances were identified and quantified using UV-vis diode array detector at wavelength 270 nm. Limits of detection (3S/N) were in the range 200-400 pg ml(-1). Proposed U-HPLC technique was used for separation of isoflavones and phenolic acids in samples of plant materials (Trifolium pratense, Glycine max, Pisum sativum and Ononis spinosa) after acid hydrolysis of the samples and modified Soxhlet extraction. PMID:18501366

  18. Gas and high-performance liquid chromatography of phenols

    Energy Technology Data Exchange (ETDEWEB)

    Tesarova, E.; Pacakova, V.

    1983-05-01

    Gas (GC) and high-performance liquid chromatographic (HPLC) methods in the analysis of phenols are reviewed. Among the great number of phenolic compounds analyzed, alkylphenols, chlorophenols, dihydroxy-and trihydroxy-benzenes and biphenols are chiefly considered. The advantages and drawbacks of the methods are discussed. Relationships between the structural characteristics of phenols, the stationary phase structure, the mobile phase composition and the retention data are treated. Typical examples of the conditions for GC and HPLC analysis are summarized in tables. 276 references

  19. Repeatability of gradient ultrahigh pressure liquid chromatography-tandem mass spectrometry methods in instrument-controlled thermal environments.

    Science.gov (United States)

    Grinias, James P; Wong, Jenny-Marie T; Kennedy, Robert T

    2016-08-26

    The impact of viscous friction on eluent temperature and column efficiency in liquid chromatography is of renewed interest as the need for pressures exceeding 1000bar to use with columns packed with sub-2μm particles has grown. One way the development of axial and radial temperature gradients that arise due to viscous friction can be affected is by the thermal environment the column is placed in. In this study, a new column oven integrated into an ultrahigh pressure liquid chromatograph that enables both still-air and forced-air operating modes is investigated to find the magnitude of the effect of the axial thermal gradient that forms in 2.1×100mm columns packed with sub-2μm particles in these modes. Temperature increases of nearly 30K were observed when the generated power of the column exceeded 25W/m. The impact of the heating due to viscous friction on the repeatability of peak capacity, elution time, and peak area ratio to an internal standard for a gradient UHPLC-MS/MS method to analyze neurotransmitters was found to be limited. This result indicates that high speed UHPLC-MS/MS gradient methods under conditions of high viscous friction may be possible without the negative effects typically observed with isocratic separations under similar conditions. PMID:27457561

  20. Column Liquid Chromatography.

    Science.gov (United States)

    Majors, Ronald E.; And Others

    1984-01-01

    Reviews literature covering developments of column liquid chromatography during 1982-83. Areas considered include: books and reviews; general theory; columns; instrumentation; detectors; automation and data handling; multidimensional chromatographic and column switching techniques; liquid-solid chromatography; normal bonded-phase, reversed-phase,…

  1. Liquid Chromatography in 1982.

    Science.gov (United States)

    Freeman, David H.

    1982-01-01

    Reviews trends in liquid chromatography including apparatus, factors affecting efficient separation of a mixture (peak sharpness and speed), simplified problem-solving, adsorption, bonded phase chromatography, ion selectivity, and size exclusion. The current trend is to control chemical selectivity by the liquid phase. (Author/JN)

  2. Equation of state of liquid Indium under high pressure

    Directory of Open Access Journals (Sweden)

    Huaming Li

    2015-09-01

    Full Text Available We apply an equation of state of a power law form to liquid Indium to study its thermodynamic properties under high temperature and high pressure. Molar volume of molten indium is calculated along the isothermal line at 710K within good precision as compared with the experimental data in an externally heated diamond anvil cell. Bulk modulus, thermal expansion and internal pressure are obtained for isothermal compression. Other thermodynamic properties are also calculated along the fitted high pressure melting line. While our results suggest that the power law form may be a better choice for the equation of state of liquids, these detailed predictions are yet to be confirmed by further experiment.

  3. Application of Ionic Liquids in High Performance Reversed-Phase Chromatography

    Directory of Open Access Journals (Sweden)

    Wentao Bi

    2009-06-01

    Full Text Available Ionic liquids, considered “green” chemicals, are widely used in many areas of analytical chemistry due to their unique properties. Recently, ionic liquids have been used as a kind of novel additive in separation and combined with silica to synthesize new stationary phase as separation media. This review will focus on the properties and mechanisms of ionic liquids and their potential applications as mobile phase modifier and surface-bonded stationary phase in reversed-phase high performance liquid chromatography (RP-HPLC. Ionic liquids demonstrate advantages and potential in chromatographic field.

  4. Ionic Liquids as Mobile Phase Additives for Separation of Nucleotides in High-Performance Liquid Chromatography

    Institute of Scientific and Technical Information of China (English)

    ZHANG,Wen-Zhu(张文珠); HE,Li-Jun(何丽君); LIU,Xia(刘霞); JIANG,Sheng-Xiang(蒋生祥)

    2004-01-01

    Ionic liquids are a type of salts that are liquid at low temperature (< 100 ℃). Because of their some special properties, they have been widely used as new "green solvents" for many chemical reactions and liquid-liquid extraction in the past several years. In this paper, a new method for the separation of nucleotides is developed and the essential feature of the method is that 1-alkyl-3-methylimidazolium salts are used as mobile phase additives, resulting in a baseline separation of nucleotides without need of gradient elution and need of organic solvent addition as currently used in RP-HPLC. This study shows the potential application of ionic liquids as mobile phase additives in reversed-phase liquid chromatography.

  5. Novel determination of polychlorinated naphthalenes in water by liquid chromatography-mass spectrometry with atmospheric pressure photoionization.

    Science.gov (United States)

    Moukas, Athanasios I; Thomaidis, Nikolaos S; Calokerinos, Antony C

    2016-01-01

    This study presents the development, optimization, and validation of a novel method for the determination of polychlorinated naphthalenes (PCNs) by liquid chromatography-atmospheric pressure photoionization (APPI), using toluene as dopant. The mass spectra of PCN 52, 54, 66, 67, 73, and 75 were recorded in negative ionization. The base ions corresponded to [M-Cl+O](-), where M is the analyte molecule. A strategy, which includes designs of experiments, for the development, the evaluation, and the optimization of the LC-APPI-MS/MS methods is also described. Finally, a highly sensitive method with low instrumental limits of detection (LoDs), ranging from 0.8 pg for PCN 75 to 16 pg for PCN 54 on column, was validated. A Thermo Hypersil Green PAH (100 mm × 2.1 mm, 3 μm) column was used with acetonitrile/water/methanol as mobile phase. The method was applied for the determination of the selected PCNs in surface and tap water samples. A simple liquid-liquid extraction method for the extraction of PCNs from water samples was used. Method LoQs ranged from 29 ng L(-1), for PCN 73, to 63 ng L(-1), for PCN 54, and the recoveries ranged from 97 to 99%, for all congeners. This is the first LC-APPI-MS/MS method for the determination of PCNs in water samples.

  6. A new and improved strategy combining a dispersive-solid phase extraction-based multiclass method with ultra high pressure liquid chromatography for analysis of low molecular weight polyphenols in vegetables.

    Science.gov (United States)

    Silva, Catarina L; Haesen, Nathaly; Câmara, José S

    2012-10-19

    This paper reports on the development and optimization of a modified Quick, Easy, Cheap Effective, Rugged and Safe (QuEChERS) based extraction technique coupled with a clean-up dispersive-solid phase extraction (dSPE) as a new, reliable and powerful strategy to enhance the extraction efficiency of free low molecular-weight polyphenols in selected species of dietary vegetables. The process involves two simple steps. First, the homogenized samples are extracted and partitioned using an organic solvent and salt solution. Then, the supernatant is further extracted and cleaned using a dSPE technique. Final clear extracts of vegetables were concentrated under vacuum to near dryness and taken up into initial mobile phase (0.1% formic acid and 20% methanol). The separation and quantification of free low molecular weight polyphenols from the vegetable extracts was achieved by ultrahigh pressure liquid chromatography (UHPLC) equipped with a phodiode array (PDA) detection system and a Trifunctional High Strength Silica capillary analytical column (HSS T3), specially designed for polar compounds. The performance of the method was assessed by studying the selectivity, linear dynamic range, the limit of detection (LOD) and limit of quantification (LOQ), precision, trueness, and matrix effects. The validation parameters of the method showed satisfactory figures of merit. Good linearity (Rvalues2>0.954; (+)-catechin in carrot samples) was achieved at the studied concentration range. Reproducibility was better than 3%. Consistent recoveries of polyphenols ranging from 78.4 to 99.9% were observed when all target vegetable samples were spiked at two concentration levels, with relative standard deviations (RSDs, n=5) lower than 2.9%. The LODs and the LOQs ranged from 0.005 μg mL(-1) (trans-resveratrol, carrot) to 0.62 μg mL(-1) (syringic acid, garlic) and from 0.016 μg mL(-1) (trans-resveratrol, carrot) to 0.87 μg mL(-1) ((+)-catechin, carrot) depending on the compound. The method

  7. Crosslinked polymeric ionic liquids as solid-phase microextraction sorbent coatings for high performance liquid chromatography.

    Science.gov (United States)

    Yu, Honglian; Merib, Josias; Anderson, Jared L

    2016-03-18

    Neat crosslinked polymeric ionic liquid (PIL) sorbent coatings for solid-phase microextraction (SPME) compatible with high-performance liquid chromatography (HPLC) are reported for the first time. Six structurally different PILs were crosslinked to nitinol supports and applied for the determination of select pharmaceutical drugs, phenolics, and insecticides. Sampling conditions including sample solution pH, extraction time, desorption solvent, desorption time, and desorption solvent volume were optimized using design of experiment (DOE). The developed PIL sorbent coatings were stable when performing extractions under acidic pH and remained intact in various organic desorption solvents (i.e., methanol, acetonitrile, acetone). The PIL-based sorbent coating polymerized from the IL monomer 1-vinyl-3-(10-hydroxydecyl) imidazolium chloride [VC10OHIM][Cl] and IL crosslinker 1,12-di(3-vinylbenzylimidazolium) dodecane dichloride [(VBIM)2C12] 2[Cl] exhibited superior extraction performance compared to the other studied PILs. The extraction efficiency of pharmaceutical drugs and phenolics increased when the film thickness of the PIL-based sorbent coating was increased while many insecticides were largely unaffected. Satisfactory analytical performance was obtained with limits of detection (LODs) ranging from 0.2 to 2 μg L(-1) for the target analytes. The accuracy of the analytical method was examined by studying the relative recovery of analytes in real water samples, including tap water and lake water, with recoveries varying from 50.2% to 115.9% and from 48.8% to 116.6%, respectively. PMID:26896916

  8. Crosslinked polymeric ionic liquids as solid-phase microextraction sorbent coatings for high performance liquid chromatography.

    Science.gov (United States)

    Yu, Honglian; Merib, Josias; Anderson, Jared L

    2016-03-18

    Neat crosslinked polymeric ionic liquid (PIL) sorbent coatings for solid-phase microextraction (SPME) compatible with high-performance liquid chromatography (HPLC) are reported for the first time. Six structurally different PILs were crosslinked to nitinol supports and applied for the determination of select pharmaceutical drugs, phenolics, and insecticides. Sampling conditions including sample solution pH, extraction time, desorption solvent, desorption time, and desorption solvent volume were optimized using design of experiment (DOE). The developed PIL sorbent coatings were stable when performing extractions under acidic pH and remained intact in various organic desorption solvents (i.e., methanol, acetonitrile, acetone). The PIL-based sorbent coating polymerized from the IL monomer 1-vinyl-3-(10-hydroxydecyl) imidazolium chloride [VC10OHIM][Cl] and IL crosslinker 1,12-di(3-vinylbenzylimidazolium) dodecane dichloride [(VBIM)2C12] 2[Cl] exhibited superior extraction performance compared to the other studied PILs. The extraction efficiency of pharmaceutical drugs and phenolics increased when the film thickness of the PIL-based sorbent coating was increased while many insecticides were largely unaffected. Satisfactory analytical performance was obtained with limits of detection (LODs) ranging from 0.2 to 2 μg L(-1) for the target analytes. The accuracy of the analytical method was examined by studying the relative recovery of analytes in real water samples, including tap water and lake water, with recoveries varying from 50.2% to 115.9% and from 48.8% to 116.6%, respectively.

  9. [An analysis of maicaodi by high performance liquid chromatography].

    Science.gov (United States)

    Yang, H; Chen, R; Jiang, M

    1997-05-01

    Maicaodi has recently been developed and produced by the pesticide plant of Nanjing Agricultural University. The quantitative analysis of the effective components--tribenuron methyl and R (-)napropamide in wettable powder of Maicaode, by a high performance liquid chromatographic method was carried out with a Lichrosorb Si-60 20cm x 0.46cm i.d. column, mobile phase of petroleum ether/isopropanol/methanol/acetonitrile/chloroform mixture solvent (80:5:5:5:5) and internal standard of diisooctyl phthalate. The sample was detected by ultraviolet absorption at 254 nm. The retention times of tribenuron methyl and R (-)napropamide were 10-11min and 6-7min respectively. The coefficient of variation of this analysis was 0.34% with a recovery of 99.51%-100.32%. The coefficient of linear correlation was 0.9999. PMID:15739379

  10. Supercooled liquid vapour pressures and related thermodynamic properties of polycyclic aromatic hydrocarbons determined by gas chromatography

    NARCIS (Netherlands)

    J.J.H. Haftka; J.R. Parsons; H.A.J. Govers

    2006-01-01

    A gas chromatographic method using Kovats retention indices has been applied to determine the liquid vapour pressure (P-i), enthalpy of vaporization (Delta H-i) and difference in heat capacity between gas and liquid phase (Delta C-i) for a group of polycyclic aromatic hydrocarbons (PAHs). This group

  11. Extraction and Purification of Glucoraphanin by Preparative High-Performance Liquid Chromatography (HPLC)

    Science.gov (United States)

    Lee, Iris; Boyce, Mary C.

    2011-01-01

    A student activity that focuses on the isolation of glucoraphanin from broccoli using preparative high-performance liquid chromatography (HPLC) is presented here. Glucoraphanin is a glucosinolate, whose byproducts are known to possess anticancer properties. It is present naturally at high levels in broccoli and other "Brassica" vegetables. This…

  12. Triacylglycerol profiling of microalgae strains for biofuel feedstock by liquid chromatography-high-resolution mass spectrometry.

    Science.gov (United States)

    MacDougall, Karen M; McNichol, Jesse; McGinn, Patrick J; O'Leary, Stephen J B; Melanson, Jeremy E

    2011-11-01

    Biofuels from photosynthetic microalgae are quickly gaining interest as a viable carbon-neutral energy source. Typically, characterization of algal feedstock involves breaking down triacylglycerols (TAG) and other intact lipids, followed by derivatization of the fatty acids to fatty acid methyl esters prior to analysis by gas chromatography (GC). However, knowledge of the intact lipid profile could offer significant advantages for discovery stage biofuel research such as the selection of an algal strain or the optimization of growth and extraction conditions. Herein, lipid extracts from microalgae were directly analyzed by ultra-high pressure liquid chromatography-mass spectrometry (UHPLC-MS) using a benchtop Orbitrap mass spectrometer. Phospholipids, glycolipids, and TAGs were analyzed in the same chromatographic run, using a combination of accurate mass and diagnostic fragment ions for identification. Using this approach, greater than 100 unique TAGs were identified over the six algal strains studied and TAG profiles were obtained to assess their potential for biofuel applications. Under the growth conditions employed, Botryococcus braunii and Scenedesmus obliquus yielded the most comprehensive TAG profile with a high abundance of TAGs containing oleic acid. PMID:21915640

  13. Simultaneous determination of three phenylethanoid glycosides in Cistanche tubulosa by online pressurized liquid microextraction-turbulent flow chromatography-high performance liquid chromatography%在线加压溶剂微提取-湍流色谱-高效液相色谱法同时测定管花肉苁蓉中3种苯乙醇苷

    Institute of Scientific and Technical Information of China (English)

    宋青青; 刘瑶; 张玲玲; 周利; 屠鹏飞; 宋月林

    2016-01-01

    An online pressurized liquid microextraction-turbulent flow chromatography-high performance liquid chromatography ( online PLME-TFC-HPLC ) platform was configured for simultaneous determination of three phenylethanoid glycosides in Cistanche tubulosa. Micro amount powder of crude material( 0. 5 mg ) was mixed with clean diatomaceous earth and packed into a vessel which then was put into a hollow guard column. To generate high tempera-ture and high pressure,a long polyetheretherketone(PEEK)tube(1 000 mm×0. 13 mm)was linked to the end of the hollow guard column that was warmed in the column oven( 70 ℃). The water containing 0. 1%( v/v)formic acid acted as the extraction solvent and was delivered at 2. 5 mL/min. Two electronic 6-port/2-channel valves were responsible for dividing the whole program into extraction and elution phases. The analytes were purified and enriched in a Turbo-Flow cyclone column,and back-flushed onto a Capcell PAK C 18 AQ column under a gradient elution program with 0. 1%( v/v ) aqueous formic acid-acetonitrile at the elution phase. The ultraviolet wavelength was set at 340 nm to monitor phenylethanoid glycosides. The calibration curves for the three phenylethanoid glycosides revealed good linearities in the range of 1-200 mg/L(r﹥0. 999). The limits of quantification(LOQs)were 0. 50 mg/L(echinacoside),0. 25 mg/L(acteoside)and 0. 38 mg/L(isoacteoside). The spiked recoveries were in the range of 83. 13%-114. 00% with the relative standard deviations( RSDs)between 1. 89% and 13. 34%. All the results indicated that this method is facile,efficient,reliable,and advantageous at time, labor,solvent,and material savings. The method also reduces the degradation risks and is suit-able for the determination of phenylethanoid glycosides in Cistanche tubulosa.%建立了在线加压溶剂微提取-湍流色谱-高效液相色谱( online PLME-TFC-HPLC)法,并将其应用于管花肉苁蓉中松果菊苷、毛蕊花糖苷和异毛蕊花糖苷3种

  14. Rapid determination of five food additives in soft drinks by high pressure liquid chromatography%高压液相色谱法快速测定饮料中的五种食品添加剂

    Institute of Scientific and Technical Information of China (English)

    魏杰; 郭志谋; 章飞芳; 梁鑫淼

    2013-01-01

    Objective To establish a high pressure liquid chromatography method for the simultaneous determination of 3 sweeteners (acesulfame-K, saccharin sodium, aspartame) and 2 preservatives (benzoic acid, sorbic acid) in soft drinks. Methods The samples were diluted with initial mobile phase and filtrated for liq-uid chromatographic analysis. The separation was performed on a polar-modified XAqua C18 column with 50 mmol/L pH 4.5 KH2PO4 and acetonitrile as mobile phase in gradient mode. The flow rate was set at 2 mL/min and column temperature was 40℃. The separation could be achieved within 6 min. And one sample could be analyzed within 10 min with the addition of 4 min equilibration time. Results Under the optimized chroma-tographic conditions, a good linearity was obtained in the range of 0.5~50 mg/L for the 5 food additives, with correlation coefficients (r2) all above 0.9999. For samples (carbonated and fruit juice beverage matrix) spiked with 50, 100 and 150 mg/kg of the 5 food additives, the recoveries and relative standard deviations (RSD) were96.48%~105.64% and 0.21%~5.39%, respectively. The limits of detection (LOD) of the method calculated by signal to noise ratio (S/N) = 3:1 was 0.02~0.08 mg/L. Conclusion The developed analysis method was rapid and accurate, and could be used for the simultaneous determination of sweeteners and preservatives in soft drinks.%  目的建立一种高压液相色谱方法同时检测饮料制品中3种甜味剂(安赛蜜、糖精钠、阿斯巴甜)和2种防腐剂(苯甲酸、山梨酸)。方法样品采用起始流动相稀释后直接过膜分析,色谱分离在极性修饰 XAqua C18色谱柱上进行,流动相采用50 mmol/L pH 4.5 KH2PO4和乙腈,梯度模式洗脱,流速2 mL/min,柱温40℃,6 min 内即可完成一次分离分析,加上4 min 梯度平衡时间,10 min 内即可完成平衡及分离。结果5种食品添加剂在0.5~50 mg/L 内线性关系良好,相关系数 r2均大于0.9999。

  15. Method validation for 243 pesticides and environmental contaminants in meats and poultry by tandem mass spectrometry coupled to low-pressure gas chromatography and ultra high-performance liquid chromatography

    Science.gov (United States)

    An easy and reliable high-throughput analysis method was developed and validated for 192 diverse pesticides and 51 environmental contaminants (13 PCB congeners, 14 PAHs, 7 PBDE congeners, and 17 novel flame retardants) in cattle, swine, and poultry muscle. Sample preparation was based on the “quick,...

  16. Separation of whey proteins for chromatography liquid

    OpenAIRE

    Abraham D. Giraldo Zuñiga; Edwin E.García Rojas; Coimbra, Jane S. R.; Wilmer E. Luera Peña

    2010-01-01

    This paper describes and compares three chromatographic methods for the analysis and quantification of most abundant proteins in cheese whey, -lactalbumin and -lactoglobulin. The methods were: Reverse-phase high performance liquid chromatography, anion Exchange chromatography and size-exclusion chromatography. The reverse- phase liquid chromatography led to a better separation of whey proteins than size-exclusion chromatography and anion exchange chromatography, this method offered an ex...

  17. Sugar Determination in Foods with a Radially Compressed High Performance Liquid Chromatography Column.

    Science.gov (United States)

    Ondrus, Martin G.; And Others

    1983-01-01

    Advocates use of Waters Associates Radial Compression Separation System for high performance liquid chromatography. Discusses instrumentation and reagents, outlining procedure for analyzing various foods and discussing typical student data. Points out potential problems due to impurities and pump seal life. Suggests use of ribose as internal…

  18. High-performance liquid chromatography for analysis of 32P-Postlabeled DNA adducts

    OpenAIRE

    Zeisig, Magnus

    1996-01-01

    High-Performance Liquid Chromatography for Analysis of 32P-Postlabeled DNA Adducts Magnus Zeisig Center for Nutrition and Toxicology, Department of Bioscience at Novum, Karolinska Institutet, Novum, S-141 57 Huddinge, SwedenThe formation of DNA adducts, i.e. the covalent binding of chemicals and chemical groups to DNA,isbelieved to be an important step in chemical carciwg...

  19. An Advanced, Interactive, High-Performance Liquid Chromatography Simulator and Instructor Resources

    Science.gov (United States)

    Boswell, Paul G.; Stoll, Dwight R.; Carr, Peter W.; Nagel, Megan L.; Vitha, Mark F.; Mabbott, Gary A.

    2013-01-01

    High-performance liquid chromatography (HPLC) simulation software has long been recognized as an effective educational tool, yet many of the existing HPLC simulators are either too expensive, outdated, or lack many important features necessary to make them widely useful for educational purposes. Here, a free, open-source HPLC simulator is…

  20. Going Beyond, Going Further: An Inexpensive Experiment for the Introduction of High Performance Liquid Chromatography.

    Science.gov (United States)

    Bidlingmeyer, Brian A.; Warren, F. Vincent, Jr.

    1984-01-01

    Background information, materials needed, laboratory procedures, and typical results are provided for five high performance liquid chromatography experiments (three isocratic and two step gradient separations). Suggestions for further experimentation are also provided, including quantitative determinations and separation of charged solutes. (JN)

  1. High-Performance Liquid Chromatography in the Undergraduate Chemical Engineering Laboratory

    Science.gov (United States)

    Frey, Douglas D.; Guo, Hui; Karnik, Nikhila

    2013-01-01

    This article describes the assembly of a simple, low-cost, high-performance liquid chromatography (HPLC) system and its use in the undergraduate chemical engineering laboratory course to perform simple experiments. By interpreting the results from these experiments students are able to gain significant experience in the general method of…

  2. High-performance liquid chromatography determination of dapsone, monoacetyldapsone, and pyrimethamine in filter paper blood spots

    DEFF Research Database (Denmark)

    Rønn, A M; Lemnge, M M; Angelo, H R;

    1995-01-01

    A high-performance liquid chromatography method for the simultaneous analysis of dapsone (DDS), the major metabolite of DDS, monoacetyldapsone (MADDS), and pyrimethamine (PYR) was modified for capillary blood samples obtained by finger prick and dried on filter paper. Limit of quantitation using...

  3. DETERMINATION OF CHLOROPHENOLS, NITROPHENOLS, AND METHYLPHENOLS IN GROUND-WATER SAMPLES USING HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

    Science.gov (United States)

    A high performance liquid chromatography (HPLC) method was developed to quantitatively determine phenolic compounds and their isomers in aqueous samples. The HPLC method can analyze a mixture of 15 contaminants in the same analytical run with an analysis time of 25 minutes. The...

  4. Serum Protein Profile Study of Clinical Samples Using High Performance Liquid Chromatography-Laser Induced Fluorescence

    DEFF Research Database (Denmark)

    Karemore, Gopal Raghunath; Ukendt, Sujatha; Rai, Lavanya;

    2009-01-01

    The serum protein profiles of normal subjects, patients diagnosed with cervical cancer, and oral cancer were recorded using High Performance Liquid Chromatography combined with Laser Induced Fluorescence detection (HPLC-LIF). Serum protein profiles of the above three classes were tested...

  5. Determination for Synthesis and Content of Tetrahydropalmatine Based on High Performance Liquid Chromatography

    OpenAIRE

    Yuanming Zhang

    2014-01-01

    Tetrahydropalmatine is a kind of food additive with useful medicine value (dietary supplement), the tetrahydropalmatine synthetic process by using high performance liquid chromatography method was researched in the study, the experiments show that the dissolution rate of active ingredients in the tetrahydropalmatine water extract synthesized by this method has increased and the amount of active ingredient has greatly improved.

  6. Determination for Synthesis and Content of Tetrahydropalmatine Based on High Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Yuanming Zhang

    2014-10-01

    Full Text Available Tetrahydropalmatine is a kind of food additive with useful medicine value (dietary supplement, the tetrahydropalmatine synthetic process by using high performance liquid chromatography method was researched in the study, the experiments show that the dissolution rate of active ingredients in the tetrahydropalmatine water extract synthesized by this method has increased and the amount of active ingredient has greatly improved.

  7. Liquid Chromatography on chip

    OpenAIRE

    Faure, Karine

    2010-01-01

    Abstract Liquid chromatography is one of the most powerful separation techniques as illustrated by its leading role in analytical sciences through both academic and industrial communities. Its implementation in microsystems appears to be crucial in the development of ?TAS. If electrophoretic techniques have been widely used in miniaturized devices, liquid chromatography has faced multiple challenges in the downsizing process. During the past five years significant breakthroughs...

  8. Preparation and evaluation of surface-bonded tricationic ionic liquid silica as stationary phases for high-performance liquid chromatography.

    Science.gov (United States)

    Qiao, Lizhen; Shi, Xianzhe; Lu, Xin; Xu, Guowang

    2015-05-29

    Two tricationic ionic liquids were prepared and then bonded onto the surface of supporting silica materials through "thiol-ene" click chemistry as new stationary phases for high-performance liquid chromatography. The obtained columns of tricationic ionic liquids were evaluated respectively in the reversed-phase liquid chromatography (RPLC) mode and hydrophilic interaction liquid chromatography (HILIC) mode, and possess ideal column efficiency of 80,000 plates/m in the RPLC mode with naphthalene as the test solute. The tricationic ionic liquid stationary phases exhibit good hydrophobic and shape selectivity to hydrophobic compounds, and RPLC retention behavior with multiple interactions. In the HILIC mode, the retention and selectivity were evaluated through the efficient separation of nucleosides and bases as well as flavonoids, and the typical HILIC retention behavior was demonstrated by investigating retention changes of hydrophilic solutes with water volume fraction in mobile phase. The results show that the tricationic ionic liquid columns possess great prospect for applications in analysis of hydrophobic and hydrophilic samples.

  9. High-Performance Liquid Chromatography Determination of Meloxicam and Piroxicam with Ultraviolet Detection

    OpenAIRE

    Sherry Cox; Joan Hayes; Jason Yarbrough; Tamara Veiga-Parga; Cheryl Greenacre

    2014-01-01

    A simple accurate and sensitive high-performance liquid chromatographic method for the determination of meloxicam and piroxicam concentrations in small volume plasma samples has been developed. Following a liquid extraction using chloroform, samples were separated by reversed-phase high-performance liquid chromatography on an XBridge C18 column (4.6 × 250 mm) and quantified using ultraviolet detection at 360 nm. The mobile phase was a mixture of water with glacial acetic acid (pH 3.0) and ace...

  10. Surface Confined Ionic Liquid-A New Stationary Phase for the Separation of Ephedrines in High-performance Liquid Chromatography

    Institute of Scientific and Technical Information of China (English)

    Shu Juan LIU; Feng ZHOU; Xiao Hua XIAO; Liang ZHAO; Xia LIU; Sheng Xiang JIANG

    2004-01-01

    In this article, a new and effective stationary phase based on ionic liquid modified silica is first reported and used for the separation of ephedrines in high-performance liquid chromatography (HPLC). The separation results indicate the high efficiency and reproducibility of the stationary phase. The electrostatic interaction, ion-exchange interaction between the solutes and the stationary phase are considered to attribute the effective separation. Moreover, the free silanols on the surface of the silica are effectively masked by the immobilized ionic liquid, a result of which is to decrease the non-specific absorption.

  11. High-throughput, Highly Sensitive Analyses of Bacterial Morphogenesis Using Ultra Performance Liquid Chromatography.

    Science.gov (United States)

    Desmarais, Samantha M; Tropini, Carolina; Miguel, Amanda; Cava, Felipe; Monds, Russell D; de Pedro, Miguel A; Huang, Kerwyn Casey

    2015-12-25

    The bacterial cell wall is a network of glycan strands cross-linked by short peptides (peptidoglycan); it is responsible for the mechanical integrity of the cell and shape determination. Liquid chromatography can be used to measure the abundance of the muropeptide subunits composing the cell wall. Characteristics such as the degree of cross-linking and average glycan strand length are known to vary across species. However, a systematic comparison among strains of a given species has yet to be undertaken, making it difficult to assess the origins of variability in peptidoglycan composition. We present a protocol for muropeptide analysis using ultra performance liquid chromatography (UPLC) and demonstrate that UPLC achieves resolution comparable with that of HPLC while requiring orders of magnitude less injection volume and a fraction of the elution time. We also developed a software platform to automate the identification and quantification of chromatographic peaks, which we demonstrate has improved accuracy relative to other software. This combined experimental and computational methodology revealed that peptidoglycan composition was approximately maintained across strains from three Gram-negative species despite taxonomical and morphological differences. Peptidoglycan composition and density were maintained after we systematically altered cell size in Escherichia coli using the antibiotic A22, indicating that cell shape is largely decoupled from the biochemistry of peptidoglycan synthesis. High-throughput, sensitive UPLC combined with our automated software for chromatographic analysis will accelerate the discovery of peptidoglycan composition and the molecular mechanisms of cell wall structure determination.

  12. Gold nanoparticle decorated graphene oxide/silica composite stationary phase for high-performance liquid chromatography.

    Science.gov (United States)

    Liang, Xiaojing; Wang, Xusheng; Ren, Haixia; Jiang, Shengxiang; Wang, Licheng; Liu, Shujuan

    2014-06-01

    In the initial phase of this study, graphene oxide (GO)/silica was fabricated by assembling GO onto the silica particles, and then gold nanoparticles (GNPs) were used to modify the GO/silica to prepare a novel stationary phase for high-performance liquid chromatography. The new stationary phase could be used in both reversed-phase chromatography and hydrophilic interaction liquid chromatography modes. Good separations of alkylbenzenes, isomerides, amino acids, nucleosides, and nucleobases were achieved in both modes. Compared with the GO/silica phase and GNPs/silica phase, it is found that except for hydrophilicity, large π-electron systems, hydrophobicity, and coordination functions, this new stationary phase also exhibited special separation performance due to the combination of 2D GO with zero-dimensional GNPs.

  13. 基于高压液相色谱法的地沟油聚类分析方法研究%The clustering analysis of the illegal cooked oil based on high pressure liquid chromatography

    Institute of Scientific and Technical Information of China (English)

    刘庆菊; 蔡波太; 袁龙飞; 周影; 黄金成; 何裕建

    2013-01-01

      目的建立基于高压液相色谱法的地沟油聚类分析方法,对地沟油进行行之有效的测定。方法假设目标油样的主要成分分为甘油三酯和其他杂质两大类,通过对其 MALDI-TOF 质谱峰的分析及高压液相色谱峰(HPLC)的聚类判别,实现地沟油的分析检测。首先利用 MALDI-TOF 质谱对油样进行初步分析;然后根据出峰时间选取了14个特征高压液相色谱峰,得到其面积百分比,并对其进行标准化处理;采用聚类分析技术将41个已知油样聚成六大类,建立样品数据库;对未知样品数据进行判别分析,可以对其进行检测。结果该方法可以检测到食用油中掺入10%的地沟油含量。将该方法用于26个盲样,结果显示,准确率为92.3%。结论该方法可以对地沟油进行有效地测定。%Objective This paper provides an effective testing method of the illegal cooked oil. Methods The triglyceride and other impurities in oil were as targets to be analyzed using MALDI-TOF mass spectrum and high pressure liquid chromatography (HPLC). First, MALDI-TOF MS was employed for preliminary analysis of oil samples; then 14 feature HPLC peaks according to the peak time and area percentage were used to carry on the standardized processing. By using the cluster analysis technology, the 41 known oil samples were gathered into 6 categories and the sample databases were established, and the discriminate analysis of the unknown samples enabled us to inspect these oils. Results Qualified edible oil mixed with 10% of the illegal cooked oil could be detected. Using this method for a blind test of 26 samples, the results showed that the total accuracy rate was 92.3%. Conclusion This method is an effective reference method for illegal cooked oil detection.

  14. Speciation analysis of mercury in water samples using dispersive liquid-liquid microextraction combined with high-performance liquid chromatography.

    Science.gov (United States)

    Gao, Zhongben; Ma, Xiaoguo

    2011-09-19

    A novel approach for preconcentration and speciation analysis of trace amount of mercury from water samples was proposed by dispersive liquid-liquid microextraction (DLLME) coupled to high performance liquid chromatography with diode array detection (HPLC-DAD). Mercury species (Hg(2+), methylmercury (MeHg(+)) and phenylmercury (PhHg(+))) were complexed with dithizone (DZ) to form hydrophobic chelates and then extracted into the fine drops of extraction solvent dispersed in the aqueous sample by dispersive solvent. After extraction, the sedimented phase was analyzed by HPLC-DAD. Some important parameters affecting the DLLME such as extraction solvent and dispersive solvent type and volume, concentration of dithizone solution, sample pH, extraction time and salt effect were investigated. Ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIM][PF(6)]) was found to be a suitable extractant for the chelates. Under the optimized conditions (extraction solvent: 70 μL of ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIM][PF(6)]); dispersive solvent: 0.75 mL of methanol containing dithizone (0.02%, m/v); pH: 4; extraction time: 5 min; and without salt addition), the limits of detection for Hg(2+), MeHg(+) and PhHg(+) were 0.32, 0.96 and 1.91 μg L(-1) (SN(-1)=3) respectively, and the relative standard deviation (RSD) was between 4.1 and 7.3% (n=5). Three real water samples (tap water, river water and lake water) spiked with mercury species were detected by the developed method, and the relative recoveries obtained for Hg(2+), MeHg(+) and PhHg(+) were 89.6-101.3%, 85.6-102.0% and 81.3-97.6%, respectively. PMID:21819859

  15. Identification of aminoglycoside-acetylating enzymes by high-pressure liquid chromatographic determination of their reaction products.

    OpenAIRE

    Lovering, A M; White, L. O.; Reeves, D S

    1984-01-01

    A method to identify the aminoglycoside-acetyltransferase (AAC) enzymes AAC(3), AAC(2') and AAC(6') by high-pressure liquid chromatographic characterization of their products of reaction with tobramycin or sisomicin is described. Conditions are given for the chromatography of kanamycin A, netilmicin, neomycin, and apramycin, and their products of reaction, if any, with the three AAC enzymes are listed.

  16. Chemical fingerprint of Ganmaoling granule by double-wavelength ultra high performance liquid chromatography and ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Lou, Qiong; Ye, Xiaolan; Zhou, Yingyi; Li, Hua; Song, Fenyun

    2015-06-01

    A method incorporating double-wavelength ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry was developed for the investigation of the chemical fingerprint of Ganmaoling granule. The chromatographic separations were performed on an ACQUITY UPLC HSS C18 column (2.1 × 50 mm, 1.8 μm) at 30°C using gradient elution with water/formic acid (1%) and acetonitrile at a flow rate of 0.4 mL/min. A total of 11 chemical constituents of Ganmaoling granule were identified from their molecular weight, UV spectra, tandem mass spectrometry data, and retention behavior by comparing the results with those of the reference standards or literature. And 25 peaks were selected as the common peaks for fingerprint analysis to evaluate the similarities among 25 batches of Ganmaoling granule. The results of principal component analysis and orthogonal projection to latent structures discriminant analysis showed that the important chemical markers that could distinguish the different batches were revealed as 4,5-di-O-caffeoylquinic acid, 3,5-di-O-caffeoylquinic acid, and 4-O-caffeoylquinic acid. This is the first report of the ultra high performance liquid chromatography chemical fingerprint and component identification of Ganmaoling granule, which could lay a foundation for further studies of Ganmaoling granule.

  17. Resolution of the stereoisomers of baclofen by high performance liquid chromatography

    International Nuclear Information System (INIS)

    The GABA analogue baclofen [3-(p-chlorophenyl)-4-aminobutanoic acid] has stereospecific actions on the peripheral and central nervous systems. This paper describes the resolution of tritium-labelled baclofen by high performance liquid chromatography on a reverse-phase C18 column using a chiral mobile phase. The method, which may have general application to certain other GABA analogues, affords optically pure (+)- and (-)-baclofen labelled with tritium to high specific activity suitable for ligand binding and other neurochemical studies. (Auth.)

  18. Resolution of the stereoisomers of baclofen by high performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Weatherby, R.P.; Allan, R.D.; Johnston, G.A.R. (Sydney Univ. (Australia))

    1984-01-01

    The GABA analogue baclofen (3-(p-chlorophenyl)-4-aminobutanoic acid) has stereospecific actions on the peripheral and central nervous systems. This paper describes the resolution of tritium-labelled baclofen by high performance liquid chromatography on a reverse-phase C18 column using a chiral mobile phase. The method, which may have general application to certain other GABA analogues, affords optically pure (+)- and (-)-baclofen labelled with tritium to high specific activity suitable for ligand binding and other neurochemical studies.

  19. Identification of Explosives from Porous Materials: Applications Using Reverse Phase High Performance Liquid Chromatography and Gas Chromatography

    Energy Technology Data Exchange (ETDEWEB)

    C.J. Miller; G. Elias; N.C. Schmitt; C. Rae

    2010-06-01

    High performance liquid chromatography and gas chromatography techniques are well documented and widely used for the detection of trace explosives from organic solvents. These techniques were modified to specifically identify and quantify explosives extracted from various materials taken from people who had recently handled explosives. Documented techniques were modified to specifically detect and quantify RDX, TNT, and PETN from denim, colored flannel, vinyl, and canvas extracted in methanol using no sample cleanup prior to analysis. The methanol extracts were injected directly into several different column types and analyzed by HPLC-UV and/or GC-ECD. This paper describes general screening methods that were used to determine the presence of explosives in unknown samples and techniques that have been optimized for quantification of each explosive from the substrate extracts.

  20. Determination of 1-hydroxypyrene in human urine by high-performance liquid chromatography

    DEFF Research Database (Denmark)

    Hansen, Åse Marie; Poulsen, O M; Christensen, J M;

    1993-01-01

    A high-performance liquid chromatography (HPLC)/fluorescence method for quantitative analysis of 1-hydroxypyrene in urine was developed. The method validation analysis showed the method to be in analytical control. No significant systematical errors could be demonstrated. The entire run time...... of chromatography was 10 min using isocratic elution (acetonitrile-water, 70:30), and the retention time for 1-hydroxypyrene was 3.5 min. The short run time in combination with the low limit detection (1.37 nmol/L) makes the method potentially applicable for surveillance of pyrene exposure in work environments...

  1. A high expression EGFR/cell membrane chromatography and online high performance liquid chromatography/mass spectrometry method for screening EGFR antagonists from Rhizoma Polygoni Cuspidati

    OpenAIRE

    Meng Sun; Yan-min Zhang; Jie Zhang; Si-cen Wang; Lang-chong He

    2011-01-01

    The epidermal growth factor receptors (EGFRs) in some tumor cells are significant targets for drug discovery. In this work, we have developed an EGFR cell membrane chromatography and online high performance liquid chromatography/mass spectrometry system for screening active component from Rhizoma Polygoni Cuspidati. As a result, resveratrol from Rhizoma Polygoni Cuspidati was found to be the active component acting on EGFR like gefitinib. There was a good relationship between their inhibiting...

  2. An Automated High Performance Capillary Liquid Chromatography Fourier Transform Ion Cyclotron Resonance Mass Spectrometer for High-Throughput Proteomics

    International Nuclear Information System (INIS)

    We report on a fully automated 9.4 tesla Fourier transform ion resonance cyclotron (FTICR) mass spectrometer coupled to reverse-phase chromatography for high-throughput proteomic studies. Modifications made to the front-end of a commercial FTICR instrument--a dual-ESI-emitter ion source; dual-channel electrodynamic ion funnel; and collisional-cooling, selection and accumulation quadrupoles--significantly improved the sensitivity, dynamic range and mass measurement accuracy of the mass spectrometer. A high-pressure capillary liquid chromatography (LC) system was incorporated with an autosampler that enabled 24 h/day operation. A novel method for accumulating ions in the ICR cell was also developed. Unattended operation of the instrument revealed the exceptional reproducibility (1-5% deviation in elution times for peptides from a bacterial proteome), repeatability (10-20% deviation in detected abundances for peptides from the same aliquot analyzed a few weeks apart) and robustness (high-throughput operation for 5 months without downtime) of the LC/FTICR system. When combined with modulated-ion-energy gated trapping, the internal calibration of FTICR mass spectra decreased dispersion of mass measurement errors for peptide identifications in conjunction with high resolution capillary LC separations to < 5 ppm over a dynamic range for each spectrum of 10 3

  3. Determination of some B Vitamins in Sour Cherry Juice Using Dispersive Liquid-liquid Microextraction Followed by High-performance Liquid Chromatography

    OpenAIRE

    Parsaei, Parvin; Bahmaei, Manouchehr; Ghannadi, Alireza

    2014-01-01

    Dispersive liquid-liquid microextraction method (DLLME) combined with high-performance liquid chromatography-ultraviolet detection (HPLC-UV) was used to determine thiamine (B1), nicotinamide (B3) and pyridoxine (B6) in sour cherry juice. This method was rapid, simple and sensitive. Separation was accomplished using a C18 column. The optimum chromatographic conditions were found to be: mobile phase consisted of 8% methanol and 92% aqueous phase (1% (V/V) acetic acid water solution); flow rate,...

  4. Analyses of acute kidney injury biomarkers by ultra-high performance liquid chromatography with mass spectrometry.

    Science.gov (United States)

    Al Za'abi, Mohammed; Ali, Badreldin H; ALOthman, Zeid A; Ali, Imran

    2016-01-01

    The newly developed acute kidney injury biomarkers are very important for the early and timely detection of kidney diseases. This review contains details of the analyses of several acute kidney injury biomarkers using ultra-high performance liquid chromatography-mass spectrometry in urine and plasma samples. In this review we attempt to discuss some aspects of the types of the biomarkers, patents, sample preparation, and the analyses. Besides, efforts were also made to discuss the possible uses of superficially porous (core-shell) columns in traditional and inexpensive high-performance liquid chromatography instruments. Additionally, the challenges and the future prospects are also highlighted. The present review will be useful for the academicians, scientists, and clinicians for the early detection of acute kidney injury biomarkers.

  5. High-Performance Liquid Chromatography Analyses of Pyoverdin Siderophores Differentiate among Phytopathogenic Fluorescent Pseudomonas Species

    OpenAIRE

    Bultreys, Alain; Gheysen, Isabelle; Wathelet, Bernard; Maraite, Henri; de Hoffmann, Edmond

    2003-01-01

    The relationship of pyoverdins produced by 41 pathovars of Pseudomonas syringae and by phytopathogenic Pseudomonas species was investigated. A high-performance liquid chromatography method for analyzing the culture medium proved to be superior to isoelectric focusing for detecting pyoverdin production, for differentiating slightly different pyoverdins, and for differentiating atypical from typical Fe(III)-chelated pyoverdins. Nonfluorescent strains were found in Pseudomonas amygdali, Pseudomo...

  6. High-performance liquid chromatography analysis of plant saponins: An update 2005-2010

    OpenAIRE

    Jagmohan S Negi; Pramod Singh; Geeta Joshi Nee Pant; Rawat, M. S. M.

    2011-01-01

    Saponins are widely distributed in plant kingdom. In view of their wide range of biological activities and occurrence as complex mixtures, saponins have been purified and separated by high-performance liquid chromatography using reverse-phase columns at lower wavelength. Mostly, saponins are not detected by ultraviolet detector due to lack of chromophores. Electrospray ionization mass spectrometry, diode array detector , evaporative light scattering detection, and charged aerosols have been u...

  7. Uronic acid determination by high performance liquid chromatography with postcolumn fluorescence derivatization.

    Science.gov (United States)

    Kakita, Hirotaka; Kamishima, Hiroshi; Inouye, Kuniyo

    2006-10-01

    To develop a fluorimetric high performance liquid chromatography (HPLC) technique for uronic acid microanalysis, a saline mobile phase and the postcolumn fluorimetric determination were combined. The detection limits of D-glucuronic, D-galacturonic and D-mannuronic acids were 7.19, 23.88 and 7.08 pmol, respectively. The proposed method was successfully applied to uronic acid microanalysis in a polysaccharide hydrolysate and a drink. PMID:16956616

  8. Quantification of furanic derivatives in fortified wines by a highly sensitive and ultrafast analytical strategy based on digitally controlled microextraction by packed sorbent combined with ultrahigh pressure liquid chromatography.

    Science.gov (United States)

    Perestrelo, Rosa; Silva, Catarina L; Câmara, José S

    2015-02-13

    An improved, reliable and powerful analytical strategy based on digitally controlled microextraction by packed sorbent (MEPS) combined with ultrahigh pressure liquid chromatography (UHPLC) was validated for the simultaneous identification and quantification of major furanic derivatives, namely 5-hydroxymethyl-2-furaldehyde (5HMF), 5-methyl-2-furaldehyde (5MF), 2-furaldehyde (2F) and 2-furyl methyl ketone (2FMK), in fortified wines. To enhance the extraction efficiency of the target furanic derivates, several influencing extraction parameters, such as number of loading cycles, nature of elution solvent and elution volume, were evaluated and optimized. In addition the ability of different MEPS sorbent materials, namely C2, C8, C18, SIL, M1, R-AX, R-CX and PGC, were also tested. The optimal analytical conditions involved loading 3×200 μL of wine samples through a C8 sorbent in a MEPS syringe placed in the semi-automatic eVolH syringe followed by elution using 200 μL MeOH:H2O (95:5, v/v). The furanic derivates separation was achieved using a CORTECS UPLC(®) C18 analytical column in an ultrafast chromatographic run (within 4 min). The method performance was assessed for dry/medium dry (D/MD) and sweet/medium sweet (S/MS) model wines in terms of selectivity, linearity, limit of detection (LOD), limit of quantitation (LOQ), accuracy, precision and matrix effect, using model wine matrix-matched calibration. Good linearity was obtained with a regression coefficient (r(2)) higher than 0.992. A good precision was attained (RSDwines. The quantification limits (LOQ) for D/MD model wines ranged from 14.9 to 431.0 ng L(-1), whereas for S/MS model wines range from 23.1 to 950.5 ng L(-1). The method also afforded satisfactory results in terms of accuracy, ranging from 74 to 97% for D/MD wines and between 84 and 99% for S/MS wines. The MEPS(C8)/UHPLC-PDA analytical strategy was successfully applied to analyze furanic derivates in 26 fortified Madeira wines from different types

  9. Chemical Investigation of Saponins in Different Parts of Panax notoginseng by Pressurized Liquid Extraction and Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Si-Jia Hong

    2012-05-01

    Full Text Available A pressurized liquid extraction (PLE and high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS method was developed for the qualitative determination of saponins in different parts of P. notoginseng, including rhizome, root, fibre root, seed, stem, leaf and flower. The samples were extracted using PLE. The analysis was achieved on a Zorbax SB-C18 column with gradient elution of acetonitrile and 8 mM aqueous ammonium acetate as mobile phase. The mass spectrometer was operated in the negative ion mode using the electrospray ionization, and a collision induced dissociation (CID experiment was also carried out to aid the identification of compounds. Forty one saponins were identified in different parts of P. notoginseng according to the fragmentation patterns and literature reports, among them, 21 saponins were confirmed by comparing the retention time and ESI-MS data with those of standard compounds. The results showed that the chemical characteristics were obviously diverse in different parts of P. notoginseng, which is helpful for pharmacological evaluation and quality control of P. notoginseng.

  10. ULTRA PERFORMANCE LIQUID CHROMATOGRAPHY: A REVIEW

    OpenAIRE

    Patil V.P.; Angadi S. S.; Kale S. H.; Devdhe S. J.; Tathe R. D

    2011-01-01

    Ultra performance liquid chromatography (UPLC) takes advantage of technological strides made in particle chemistry performance, system optimization, detector design and data processing and control. Using sub-2 mm particles and mobile phases at high linear velocities and instrumentation that operates at higher pressures than those used in HPLC, dramatic increases in resolution, sensitivity and speed of analysis can be obtained. This new category of analytical separation science retains the pra...

  11. Measurement of lumefantrine and its metabolite in plasma by high performance liquid chromatography with ultraviolet detection

    DEFF Research Database (Denmark)

    Khalil, Insaf F; Abildrup, Ulla; Alifrangis, Lene H;

    2011-01-01

    some limitations in terms of high costs and limited feasibility arising from large required sample volumes and demanding sample preparation. Therefore, we set out to develop a simpler reversed phase high performance liquid chromatography (RP-HPLC) method based on UV detection for simultaneous......Artemether-lumefantrine (ARM-LUM) has in recent years become the first-line treatment for uncomplicated malaria in many Sub-Saharan African countries. Vigorous monitoring of the therapeutic efficacy of this treatment is needed. This requires high-quality studies following standard protocols...... measurement of LUM and its major metabolite the desbutyl LUM (DL) in plasma. Halofantrine was used as an internal standard. Liquid-liquid extraction of samples was carried out using hexane-ethyl acetate (70:30, v/v). Chromatographic separation was carried out on a Synergi Polar-RP column (250 mm × 300 mm...

  12. Ultra high performance liquid chromatography versus high performance liquid chromatography: stationary phase selectivity for generic carotenoid screening.

    Science.gov (United States)

    Bijttebier, Sebastiaan; D'Hondt, Els; Noten, Bart; Hermans, Nina; Apers, Sandra; Voorspoels, Stefan

    2014-03-01

    Aim of study was to find the most suitable LC column for generic carotenoid screening. To represent the diversity of carotenoids in nature and to optimize chromatographic separation, a set of carotenoid standards was carefully chosen to account for the various classes of carotenoids. The HPLC C30 column has since long been the 'golden standard' in the chromatographic separation of carotenoids. Since approximately one decade, new UHPLC technology has led to much shorter analysis times, smaller peak widths and higher chromatographic resolution. However, there are currently no UHPLC columns on the market containing the specific stationary phase chemistry of the HPLC C30 column. Therefore during this study, we investigated the separation of carotenoids on a set of UHPLC columns and compared it to their separation on the HPLC C30 column. Comparison of carotenoids separations on the different stationary phases with objective column comparison parameters clearly indicated that the HPLC C30 column is an overall better performer in the separation of carotenoids. This is due to the lack of UHPLC column chemistries that are adapted for carotenoid analysis. However, analysis time on the HPLC C30 column takes about four times longer compared to UHPLC analysis. Therefore, with the range of columns that are commercially available nowadays, a choice has to be made between very high selectivity (HPLC C30 column) and analysis times that are adapted to modern laboratory requirements (UHPLC technology). Therefore, carotenoid separations would be even more performing if an appropriate UHPLC C30 column would be available. PMID:24534422

  13. Recent advances in ultra-high performance liquid chromatography for the analysis of traditional chinese medicine

    Science.gov (United States)

    Traditional Chinese medicines (TCMs) have been widely used for the prevention and treatment of various diseases for thousands of years in China. Ultra Performance Liquid Chromatography (UHPLC) is a relatively new technique offering new possibilities in liquid chromatography. This paper reviews recen...

  14. [Qualitative and quantitative analysis of the amino acids in Rhizoma Arisaematis by ultra high performance liquid chromatography-tandem mass spectrometry and high performance liquid chromatography].

    Science.gov (United States)

    Wang, Xing; Chi, Yumei; Kang, An

    2014-12-01

    A method for the identification and determination of the polar amino components without ultraviolet activity in traditional Chinese medicines was developed. With Rhizoma Arisaematis as the object of this study, using pre-column derivatization with phenyl isothiocyanate (PITC) as the derivatization reagent, compounds were separated and identified on a C18 column (100 mm x 2.1 mm, 3.5 µm) by ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). A total of 20 components, including 18 amino acids and 2 amine compounds were identified. Furthermore, after the optimization of the derivatization conditions, 15 amino acids were determined by high performance liquid chromatography (HPLC) on Diamonsil C18 column (250 mm x 4.6 mm, 5 µm), detected at 254 nm and gradiently eluted by acetonitrile and 0. 05 mol/L ammonium acetate-acetic acid (pH 6. 5) as the mobile phases. The results of methodological study demonstrated that the method can meet the requirements of the determination. All calibration curves expressed good linearity: Glu, Try in the range of 2-100 mg/L, Arg in the range of 6-300 mg/L, others in the range of 0. 8-40 µg/L, with the correlation coefficients ≥ 0. 999 5. The average recovery of this method was among 95%-105% and the RSD was less than 3%. The developed method was successfully applied to quantitative determination of amino compounds in 12 batches of Rhizoma Arisaematis samples. The method is simple, sensitive, accurate, and can be used for rapid identification and determination of amino components in traditional Chinese medicines.

  15. Studies on Chromatography Fingerprint of Hongqi by High-performance Liquid Chromatography

    Institute of Scientific and Technical Information of China (English)

    Shi Lan FENG; Fang Di HU; Jian Xiong ZHAO; Jing Wen XU; Li Ren CHEN

    2004-01-01

    Chromatography fingerprint (CFP) of 10 samples of hongqi were studied. 23 common peaks were analyzed, their average similarity was 97.29%. CFP were positioned with main index composition such as formononetin, calycosin and then the contents of index composition were determined. The character and exclusive of CFP of 10 samples of hongqi were clear. CFP and content determination of index composition of hongqi could be used to evaluate the quality of hongqi comprehensively.

  16. High performance liquid chromatography-mass spectrometry analysis of high antioxidant australian fruits with antiproliferative activity against cancer cells

    Directory of Open Access Journals (Sweden)

    Joseph Sirdaarta

    2016-01-01

    Abbreviations used: DPPH: di (phenyl- (2,4,6-trinitrophenyl iminoazanium, HPLC: High-performance liquid chromatography, IC50: The concentration required to inhibit by 50%, LC50: The concentration required to achieve 50% mortality, MS: Mass spectrometry. Ian Edwin Cock

  17. Relationship between High-Performance Liquid Chromatography Fingerprints and Uric Acid-Lowering Activities of Cichorium intybus L.

    OpenAIRE

    Chun-Sheng Zhu; Bing Zhang; Zhi-Jian Lin; Xue-Jie Wang; Yue Zhou; Xiao-Xia Sun; Ming-Liang Xiao

    2015-01-01

    This study aimed to explore the spectrum-effect relationships between high-performance liquid chromatography fingerprints and the uric acid-lowering activities of chicory. Chemical fingerprints of chicory samples from ten different sources were determined by high-performance liquid chromatography, and then investigated by similarity analysis and hierarchical clustering analysis. Pharmacodynamics experiments were conducted in animals to obtain the uric acid-lowering activity information of ea...

  18. PREPARATIVE ISOLATION AND PURIFICATION OF FIVE FLAVONOIDS FROM POGOSTEMON CABLIN BENTH BY HIGH-SPEED COUNTERCURRENT CHROMATOGRAPHY AND PREPARATIVE HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY

    OpenAIRE

    Li, Kang; Zhang, Hongwu; Xie, Huichun; Liang, Yong; Wang, Xiaohong; Ito, Yoichiro

    2011-01-01

    High-speed countercurrent chromatography (HSCCC) and preparative high-performance liquid chromatography (prep-HPLC) were successively used for the separation of pogostone and four flavonoids from Pogostemon cablin (Blanco) Benth. An efficient HSCCC separation was achieved on a two-phase solvent system composed of n-hexane–ethyl acetate–methanol–water (11:5:11:5, v/v/v/v). Three well-separated peaks were obtained in the HSCCC chromatogram. The first and the second fractions each contained two ...

  19. Preliminary Validation of High Performance Liquid Chromatography Method for Detection of Methyltestosterone Residue in Carp Muscle

    Institute of Scientific and Technical Information of China (English)

    JIANG Jie; LIN Hong; FU Xiaoting; LI Mingming

    2005-01-01

    The use of synthetic anabolic steroid methyltestosterone (MT) as growth promoter is prohibited in China. Validations of analytical methods for MT residue in food and the results obtained have become indispensable. The high performance liquid chromatography (HPLC) method for the detection of MT with liquid-liquid extraction by trichloromethanemethanol in carp muscle tissue was preliminarily validated with reference to the following parameters: recovery (accuracy)at the 1, 5 and 10 mgkg-1 level, between-run and within-run CV values (repeatability, also called relative standard deviation(RSD)) and limit of detection. The recoveries were above 80% and the between-run and within-run CV values below 10%for muscle tissue. The limit of detection was 0.05 mgkg-1.

  20. Preparation and Characterization of a Polymeric Monolithic Column for Use in High-Performance Liquid Chromatography (HPLC)

    Science.gov (United States)

    Bindis, Michael P.; Bretz, Stacey Lowery; Danielson, Neil D.

    2011-01-01

    The high-performance liquid chromatography (HPLC) experiment, most often done in the undergraduate analytical instrumentation laboratory course, generally illustrates reversed-phase chromatography using a commercial C[subscript]18 silica column. To avoid the expense of periodic column replacement and introduce a choice of columns with different…

  1. tRNA separation by high-performance liquid chromatography using an aggregate of ODS-Hypersil and trioctylmethylammonium chloride

    NARCIS (Netherlands)

    Bischoff, Rainer; Graeser, E.; Mclaughlin, L.W.

    1983-01-01

    High-performance liquid chromatography on a reversed-phase support treated with a tetraalkylammonium salt was used to separate tRNAs from baker's yeast. While resolution by this column appears to result from both anion-exchange and reversed-phase chromatography, it is the hydrophobic interactions wh

  2. Tunnel frit: a nonmetallic in-capillary frit for nanoflow ultra high-performance liquid chromatography-mass spectrometryapplications.

    Science.gov (United States)

    Chen, Chao-Jung; Chen, Wei-Yun; Tseng, Mei-Chun; Chen, Yet-Ran

    2012-01-01

    In this study, an easy method to fabricate a durable in-capillary frit was developed for use in nanoflow liquid chromatography (nanoLC). A small orifice was tunneled into the sol-gel frit during the polymerization process resulting in the simple fabrication of a tunnel frit. A short packing tunnel frit column (2 cm, C(18) particles) was able to sustain over 10,000 psi continuous liquid flow for 10 days without observation of particle loss, and back pressure variation was less than 5%. The tunnel frit was successfully applied to the fabrication of nanoflow ultra high-performance liquid chromatography (nano-UHPLC) trap and analytical columns. In the analysis of tryptic peptides, the tunnel frit trap and analytical columns were demonstrated to have high separation efficiency and sensitivity. In analysis of phosphopeptides, the use of the nonmetallic tunnel frit column showed better sensitivity than the metallic frit column. This design can facilitate the preparation of nano-HPLC and nano-UHPLC columns and the packing material can easily be refilled when the column is severely contaminated or clogged. PMID:22097963

  3. Quantitative determination of acetylcholine in microdialysis samples using liquid chromatography/atmospheric pressure spray ionization mass spectrometry.

    Science.gov (United States)

    Keski-Rahkonen, Pekka; Lehtonen, Marko; Ihalainen, Jouni; Sarajärvi, Timo; Auriola, Seppo

    2007-01-01

    A fast, simple and sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed for the determination of acetylcholine in rat brain microdialysis samples. The chromatographic separation was achieved in 3 min on a reversed-phase column with isocratic conditions using a mobile phase containing 2% (v/v) of acetonitrile and 0.05% (v/v) of trifluoroacetic acid (TFA). A stable isotope-labeled internal standard was included in the analysis and detection was carried out with a linear ion trap mass spectrometer using selected reaction monitoring (SRM). Analyte ionization was performed with an atmospheric pressure chemical ionization (APCI) source without applying discharge current (atmospheric pressure spray ionization). This special ionization technique offered significant advantages over electrospray ionization for the analysis of acetylcholine with reversed-phase ion-pairing chromatography. The lower limit of quantification was 0.15 nM (1.5 fmol on-column) and linearity was maintained over the range of 0.15-73 nM, providing a concentration range that is significantly wider than that of the existing LC/MS methods. Good accuracy and precision were obtained for concentrations within the standard curve range. The method was validated and has been used extensively for the determination of acetylcholine in rat brain microdialysis samples.

  4. Denaturing high-performance liquid chromatography mutation analysis in patients with reduced Protein S levels

    DEFF Research Database (Denmark)

    Bathum, Lise; Münster, Anna-Marie; Nybo, Mads;

    2008-01-01

    diagnosis and risk estimation. The aim was to design a high-throughput genetic analysis based on denaturing high-performance liquid chromatography to identify sequence variations in the gene coding for Protein S. PATIENTS: In total, 55 patients referred to the Section of Thrombosis and Haemostasis, Odense...... were missense mutations (c.932T>G; c.1367A>G; c.1378T>C). Furthermore, four patients carried the same mutation (c.1045G>A), while two carried the Heerlen mutation (c.1378T>C). CONCLUSIONS: The reported method will be useful for rapidly detecting sequence variations in the gene coding for Protein S...

  5. Ultrapressure liquid chromatography-tandem mass spectrometry assay using atmospheric pressure photoionization (UPLC-APPI-MS/MS) for quantification of 4-methoxydiphenylmethane in pharmacokinetic evaluation.

    Science.gov (United States)

    Farhan, Nashid; Fitzpatrick, Sean; Shim, Yun M; Paige, Mikell; Chow, Diana Shu-Lian

    2016-09-01

    4-Methoxydiphenylmethane (4-MDM), a selective augmenter of Leukotriene A4 Hydrolase (LTA4H), is a new anti-inflammatory compound for potential treatment of chronic obstructive pulmonary disease (COPD). Currently, there is no liquid chromatography tandem mass spectrometric (LC-MS/MS) method for the quantification of 4-MDM. A major barrier for developing the LC-MS/MS method is the inability of electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) to ionize 4-MDM due to its hydrophobicity and lack of any functional group for ionization. With the advent of atmospheric pressure photoionization (APPI) technique, many hydrophobic compounds have been demonstrated to ionize by charge transfer reactions. In this study, a highly sensitive ultrapressure liquid chromatography tandem mass spectrometry assay using atmospheric pressure photoionization (UPLC-APPI-MS/MS) for the quantifications of 4-MDM in rat plasma has been developed and validated. 4-MDM was extracted from the plasma by solid phase extraction (SPE) and separated chromatographically using a reverse phase C8 column. The photoionization (PI) was achieved by introducing anisole as a dopant to promote the reaction of charge transfer. The assay with a linear range of 5 (LLOQ)-400ngmL(-1) met the regulatory requirements for accuracy, precision and stability. The validated assay was employed to quantify the plasma concentrations of 4-MDM after an oral dosing in Sprague Dawley (SD) rats. PMID:27232150

  6. Ultrapressure liquid chromatography-tandem mass spectrometry assay using atmospheric pressure photoionization (UPLC-APPI-MS/MS) for quantification of 4-methoxydiphenylmethane in pharmacokinetic evaluation.

    Science.gov (United States)

    Farhan, Nashid; Fitzpatrick, Sean; Shim, Yun M; Paige, Mikell; Chow, Diana Shu-Lian

    2016-09-01

    4-Methoxydiphenylmethane (4-MDM), a selective augmenter of Leukotriene A4 Hydrolase (LTA4H), is a new anti-inflammatory compound for potential treatment of chronic obstructive pulmonary disease (COPD). Currently, there is no liquid chromatography tandem mass spectrometric (LC-MS/MS) method for the quantification of 4-MDM. A major barrier for developing the LC-MS/MS method is the inability of electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) to ionize 4-MDM due to its hydrophobicity and lack of any functional group for ionization. With the advent of atmospheric pressure photoionization (APPI) technique, many hydrophobic compounds have been demonstrated to ionize by charge transfer reactions. In this study, a highly sensitive ultrapressure liquid chromatography tandem mass spectrometry assay using atmospheric pressure photoionization (UPLC-APPI-MS/MS) for the quantifications of 4-MDM in rat plasma has been developed and validated. 4-MDM was extracted from the plasma by solid phase extraction (SPE) and separated chromatographically using a reverse phase C8 column. The photoionization (PI) was achieved by introducing anisole as a dopant to promote the reaction of charge transfer. The assay with a linear range of 5 (LLOQ)-400ngmL(-1) met the regulatory requirements for accuracy, precision and stability. The validated assay was employed to quantify the plasma concentrations of 4-MDM after an oral dosing in Sprague Dawley (SD) rats.

  7. High-pressure liquid chromatographic method for the determination of patulin in apple butter.

    Science.gov (United States)

    Ware, G M

    1975-07-01

    Patulin is extracted from apple butter samples with ethyl acetate and the extract is cleaned up on a silica gel column, using benzene-ethyl acetate (75+25) as the eluant. High-pressure liquid chromatography, using a 25 cm ZorbaxSil column, isooctane-ethyl ether-acetic acid (750+250+0.5) as the mobile solvent, and a 254 nm ultraviolet detector, is used for the determinative step. Under these conditions, patulin is eluted before 5-hydroxymethylfurfural, a component of apple butter which interferes with other liquid chromatographic and thin layer chromatographic methods. Recoveries of patulin added at levels of 34.6, 138.4, and 276.8 mug/kg ranged from 89.0 to 112.1%. PMID:168176

  8. Microwave-assisted ionic liquid homogeneous liquid-liquid microextraction coupled with high performance liquid chromatography for the determination of anthraquinones in Rheum palmatum L.

    Science.gov (United States)

    Wang, Zhibing; Hu, Jianxue; Du, Hongxia; He, Shuang; Li, Qing; Zhang, Hanqi

    2016-06-01

    The microwave-assisted ionic liquid homogeneous liquid-liquid microextraction (MA-IL-HLLME) coupled with high performance liquid chromatography with diode array detection (HPLC-DAD) was developed for the determination of anthraquinones, including aloe-emodin, emodin, chrysophanol and physcion in root of Rheum palmatum L. Several experimental parameters influencing the extraction efficiency, including amount of sample, type and volume of ionic liquid, volume and pH value of extraction medium, microwave power and extraction time, concentration of NH4PF6 as well as centrifugal condition were optimized. When 140μL of ionic liquid ([C8MIM][BF4]) was used as an extraction solvent, target analytes can be extracted from sample matrix in one minute with the help of microwave irradiation. The MA-IL-HLLME is simple and quick. The calibration curves exhibited good linear relationship (r>0.9984). The limits of detection and quantification were in the range of 0.015-0.026 and 0.051-0.088μgmL(-1), respectively. The spiked recovery for each analyte was in the range of 81.13-93.07% with relative standard deviations lower than 6.89%. The present method is free of volatile organic solvents, and represents lower expenditures of sample, extraction time and solvent, compared with ultrasonic and heat reflux extraction. The results indicated that the present method can be successfully applied to the determination of anthraquinones in medicinal plant.

  9. [Determination of five triazine herbicides in infant milk powder by high performance liquid chromatography coupled with ionic liquid-based homogeneous liquid-liquid microextraction].

    Science.gov (United States)

    Zhang, Liyuan; Yao, Di; Li, Na; Zhang, Hanqi; Yu, Aimin

    2015-07-01

    A high performance liquid chromatography coupled with homogeneous liquid-liquid microextraction was developed for the determination of five triazine herbicides in infant milk powders. The ionic liquid was used as microextraction solvent. The separation of the herbicides was performed on an Eclipse XDB-C18 column using acetonitrile and water as mobile phases in gradient mode. The effects of homogeneous liquid-liquid extraction conditions on the experimental results were investigated in detail. Under the optimized experimental conditions, the calibration curves for determining the analytes were linear and the correlation coefficients were ≥ 0.9992. The limits of detection for cyanazine, desmetryn, terbumeton, terbuthylazine and dimethametryn were 12.1, 13.8, 11.8, 14.6 and 13.7 μg/kg, respectively. The recoveries of the analytes spiked in four infant milk powders ranged from 92.2% to 103.2% and the relative standard deviations were lower than 6%. This method is sensitive, simple, and suitable for the determination of triazine herbicides in milk powder samples.

  10. Ultra high efficiency/low pressure supercritical fluid chromatography with superficially porous particles for triglyceride separation.

    Science.gov (United States)

    Lesellier, E; Latos, A; de Oliveira, A Lopes

    2014-01-31

    This paper reports the development of the separation of vegetable oil triglycerides (TG) in supercritical chromatography (SFC), using superficially porous particles (SPPs). The SPP, having a small diameter (2-3μm), provide a higher theoretical plate number (N), which allows to improve separation of critical pairs of compounds. However, compared to fully porous particles of larger diameter (5μm), the pressure drop is also increased. Fortunately, supercritical fluids have a low viscosity, which allows coupling several columns to achieve high N values, while maintaining flow rate above 1ml/min, ensuring a ultra high efficiency (UHE) at low pressure (LP) (below 40MPa), with regards to the one reached with liquid and sub-two micron particles (around 100MPa). The use of two detector systems (UV and ELSD) connected in series to the UHE-LP-SFC system provides complementary responses, due to their specific detection principles. Working in a first part with three coupled Kinetex C18 columns (45cm total length), the effect of modifier nature and percentage were studied with two reference oils, argan and rapeseed, chosen for their different and well-known TG composition. The analytical method was developed from previous studies performed with fully porous particles (FPP). Optimized conditions with three Kinetex were as follows: 17°C, 12% of ACN/MeOH (90/10; v/v). With these conditions, and by using an increased length of Kinetex C18 column (60cm), another additional column was selected from ten different commercial SPP C18 bonded phases, by applying a Derringer function on varied parameters: theoretical plate number (TPN), separation index (SI) for critical pairs of peaks (the peaks of compounds difficult to separate due to subtle structural differences), the analysis duration, and the total peak number. This function normalizes the values of any parameters, between 0 and 1, from the worst value to the better, allowing to take account of various parameters in the final

  11. Ultra high efficiency/low pressure supercritical fluid chromatography with superficially porous particles for triglyceride separation.

    Science.gov (United States)

    Lesellier, E; Latos, A; de Oliveira, A Lopes

    2014-01-31

    This paper reports the development of the separation of vegetable oil triglycerides (TG) in supercritical chromatography (SFC), using superficially porous particles (SPPs). The SPP, having a small diameter (2-3μm), provide a higher theoretical plate number (N), which allows to improve separation of critical pairs of compounds. However, compared to fully porous particles of larger diameter (5μm), the pressure drop is also increased. Fortunately, supercritical fluids have a low viscosity, which allows coupling several columns to achieve high N values, while maintaining flow rate above 1ml/min, ensuring a ultra high efficiency (UHE) at low pressure (LP) (below 40MPa), with regards to the one reached with liquid and sub-two micron particles (around 100MPa). The use of two detector systems (UV and ELSD) connected in series to the UHE-LP-SFC system provides complementary responses, due to their specific detection principles. Working in a first part with three coupled Kinetex C18 columns (45cm total length), the effect of modifier nature and percentage were studied with two reference oils, argan and rapeseed, chosen for their different and well-known TG composition. The analytical method was developed from previous studies performed with fully porous particles (FPP). Optimized conditions with three Kinetex were as follows: 17°C, 12% of ACN/MeOH (90/10; v/v). With these conditions, and by using an increased length of Kinetex C18 column (60cm), another additional column was selected from ten different commercial SPP C18 bonded phases, by applying a Derringer function on varied parameters: theoretical plate number (TPN), separation index (SI) for critical pairs of peaks (the peaks of compounds difficult to separate due to subtle structural differences), the analysis duration, and the total peak number. This function normalizes the values of any parameters, between 0 and 1, from the worst value to the better, allowing to take account of various parameters in the final

  12. Ambient temperature nanoelectrospray ion mobility detector for high performance liquid chromatography in determining amines.

    Science.gov (United States)

    Chen, Chuang; Hou, Keyong; Wang, Weiguo; Li, Jinghua; Li, Haiyang

    2014-09-01

    A nanoelectrospray ionization ion mobility spectrometer (nanoESI-IMS) working at ambient pressure and ambient temperature was developed as a detector of high performance liquid chromatography (HPLC) to achieve sensitive detection of amines with no derivatization and meanwhile provide another dimension of separation. The easier desolvation property of the charged droplets formed in nanoESI source enabled complete desolvation of the product ions of sixteen amines and drugs using the nanoESI-IMS at ambient temperature. Working at ambient temperature was good for suppressing the dissociation of thermal volatile ions, such as only the proton adducted molecular ions were observed for morphine in the nanoESI-IMS. Besides, the resolving power of the nanoESI-IMS also showed an increasing tendency as lowering the working temperature, an increment of 19 percent and 10 percent was observed for diethylamine and triethylamine as the temperature dropped from 92°C to 32°C. The resolving power of the nanoESI-IMS at 32°C for the 16 tested compounds was amid 33-44. With the nanoESI-IMS coupled to HPLC, a six-compound mixture including isomers was successfully separated and detected without any derivatization. And linear response ranges of 1 to 20, 0.5 to 20, and 0.8 to 20μgml(-1) and limits of detection of 0.25, 0.15, and 0.17μgml(-1) for triethylamine, diethylamine, and butylamine, respectively, were obtained with the hyphenated system. These results showed the excellent performance of the two-dimensional separation and detection method in direct qualitative and quantitative analyses of amines.

  13. Determination of anabolic agents in dietary supplements by liquid chromatography-high-resolution mass spectrometry.

    Science.gov (United States)

    Odoardi, Sara; Castrignanò, Erika; Martello, Simona; Chiarotti, Marcello; Strano-Rossi, Sabina

    2015-01-01

    A sensitive method for the identification and quantification of anabolic steroids and clenbuterol at trace levels in dietary supplements by liquid chromatography-high-resolution mass spectrometry (LC-HRMS) in atmospheric pressure ionisation (APCI) mode using a single-stage Orbitrap analyser operating at a resolution power of 100 000 full width at half maximum (FWHM) was developed and validated. A total of 1 g of dietary supplement was added with testosterone-d3 as internal standard, dissolved in methanol, evaporated to dryness, diluted in sodium hydroxide solution and extracted with a mixture of pentane/ethyl ether 9:1. The extract was directly injected into the LC-HRMS system. The method was fully validated. Limits of detection (LODs) obtained for anabolic androgenic steroids (AASs) varied from 1 to 25 ng g(-1) and the limit of quantitation (LOQ) was 50 ng g(-1) for all analytes. The calibration was linear for all compounds in the range from the LOQ to 2000 ng g(-1), with correlation coefficients always higher than 0.99. Accuracy (intended as %E) and repeatability (%CV) were always lower than 15%. Good values of matrix effect and recovery were achieved. The ease of the sample preparation together with a fast run time of only 16 min permitted rapid identification of the analytes. The method was applied to the analysis of 30 dietary supplements in order to check for the presence of anabolic agents not labelled as being present in these supplements. Many AASs were often detected in the same sample: indeed, androstenedione was detected in nine supplements, 5-androsten-3β-ol-17-one (DHEA) in 12, methandienone in three, stanozolol in one, testosterone in seven and testosterone esters in four of them. A retrospective analysis of suspected compounds not included at the beginning of the method development was also possible by means of the full acquisition spectra obtained with the HRMS technique.

  14. Validation of quantitative determination methods of diphenhyramine tablets by high performance liquid chromatography

    OpenAIRE

    Zagorodniy, S. L.; Vasyuk, S. O.

    2015-01-01

    Aim. In order to quantify diphenhydramine tablets the methods based on reverse phase high-performance liquid chromatography with UV-spectrometry detection at 254 nm (HPLC-UV) have been used.Methods and results. The mobile phase used a mixture of a phosphate buffer: acetonitrile (80:20). The proposed method is applied to the two dosage forms of diphenhydramine – tablets to 0.1 and 0.05, produced by various Ukrainian pharmaceutical companies. The main characteristics are validated by Pharmacopo...

  15. Determination of enantiomeric impurity of etomidate by high performance liquid chromatography

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Objective To determine enantiomeric impurity of etomidate using high performance liquid chromatography. Methods (R)-etomidate and (S)-etomidate were separated on a CHIRALPAK AD-H column. The mobile phase consisted of 20∶80(v/v) isopropanol-n-hexane. The flow rate of the mobile phase was 0.5mL/min. The detected wavelength was 242nm. Results (R)-etomidate and (S)-etomidate could be separated completely under these conditions. The precision of (R)-etomidate was 1.57% (n=3). The limit of detection of (R)-etomid...

  16. High-performance liquid chromatography of rat and mouse islet polypeptides

    DEFF Research Database (Denmark)

    Linde, S; Hansen, B; Welinder, B S;

    1990-01-01

    After preparative high-performance liquid chromatography of mouse islet culture medium, concentrated on disposable C18 cartridges (Sep-Pak), an unexpected insulin immunoreactive peak eluting earlier than mouse insulin I and II was detected. Molecular mass determination by mass spectrometry...... on the buffer, the organic modifier and the procedure. In particular the use of methanol-trifluoroacetic acid resulted in extensive oxidation. The oxidation could be minimized by adding 2 mM dithiothreitol to the buffer and by degassing and/or nitrogen-bubbling of the buffer. Minimal formation of Met...

  17. On-line radiochemical assay for monoamine oxidase utilizing high-performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Nissinen, E.; Linko-Loeppoenen SMae; Maennistoe P4

    1984-12-01

    A fast and sensitive assay for the determination of monoamine oxidase activity was developed. The method is based on the separation and quantitation of /sup 14/C-labeled assay products by high-performance liquid chromatography, which is interfaced directly into a flow-through radioactivity detector. This allows on-line quantitation of the radioactive compounds with picomole sensitivity. The method makes possible the complete separation and detection of the deaminated products of monoamine oxidase A and B substrates benzylamine and 5-hydroxytryptamine, respectively. This assay has been applied to the measurement of monoamine oxidase A and B activities in rat brain.

  18. Quantitative Analysis of Rutin in Buckwheat (Fagopyrum sp.) by High Performance Liquid Chromatography

    OpenAIRE

    Minami, M; Kitabayashi, H; Ujihara, A

    1998-01-01

    For the quantitative analysis of rutin in common buckwheat (Fagopyrum esculentum) and tartary buckwheat (F. tataricum), the operating condition of high performance liquid chromatography (HPLC) and methods of sample preparation and extraction were investigated. Reliable analysis method with less than 5 g of sample was established as follows; ① drying samples for 24 hours at 70℃ by using forced air flow oven,② grinding 5 g of seed and 2 g of leaf samples into powder for 30 seconds,③ extracting ...

  19. Purification of selective labelled monoiodotyrosine insulins by reversed phase high performance liquid chromatography

    International Nuclear Information System (INIS)

    The four monoiodinated insulin derivates were prepared by a modification of the lactoperoxidase method. The iodinated insulin mixture was then separated by reserved-phase high-performance liquid chromatography and the identity of iodinated products was assessed by sequential oxidative sulphytolysis and enzymatic proteolysis. A total separation of the A14, A19, B16 and B26 monoiodinated insulins from one another and from unreacted insulin was accomplished. Thus, the reported procedure represents a rapid, selective and generally applicable method for purifying insulin derivates selectively labelled in one of the four tyroisine residues

  20. Determination of Aspartame, Caffeine, Saccharin, and Benzoic Acid in Beverages by High Performance Liquid Chromatography.

    Science.gov (United States)

    Delaney, Michael F.; And Others

    1985-01-01

    Describes a simple and reliable new quantitative analysis experiment using liquid chromatography for the determinaiton of caffeine, saccharin, and sodium benzoate in beverages. Background information, procedures used, and typical results obtained are provided. (JN)

  1. Determination of nine high-intensity sweeteners in various foods by high-performance liquid chromatography with mass spectrometric detection

    OpenAIRE

    Zygler, Agata; Wasik, Andrzej; Kot-Wasik, Agata; Namieśnik, Jacek

    2011-01-01

    An analytical procedure involving solid-phase extraction (SPE) and high-performance liquid chromatography-mass spectrometry has been developed for the determination of nine high-intensity sweeteners authorised in the EU; acesulfame-K (ACS-K), aspartame (ASP), alitame (ALI), cyclamate (CYC), dulcin (DUL), neohesperidin dihydrochalcone (NHDC), neotame (NEO), saccharin (SAC) and sucralose (SCL) in a variety of food samples (i.e. beverages, dairy and fish products). After extraction with a buffer...

  2. Simultaneous determination of airborne carbamates in workplace by high performance liquid chromatography with fluorescence detection.

    Science.gov (United States)

    Li, Hong-Ping; Li, Jen-Hou; Li, Gwo-Chen; Jen, Jen-Fon

    2004-06-17

    A high performance liquid chromatography with fluorescence (HPLC-F) detector was examined to simultaneous determination of airborne carbamates in the workplace of manufactory. The OVS-2 air sampling tube filled with glass fiber filter or quartz fiber and combined filter/XAD-2 were evaluated to collect nine commonly used carbamates (Carbofuran, Isoprocarb, Methomyl, Metolcarb, Thiodicarb, Carbaryl, Oxamyl, Methiocarb, and Prpoxur) from the air of manufactory in high humidity country. After being extracted with acetonitrile from sampling tubes, the carbamates were determined by high performance liquid chromatography with fluorescence detection posterior to on-line derivatization. The collection of carbamates and the recovery of extraction from glass wool fiber in several concentration levels, and from quartz filter were evaluated. The storage stability of carbamates was also tested. Results indicated that the HPLC-fluorescence method offers satisfactory resolution and sensitivity in carbamate analysis. With the glass fiber filter and combined filter/XAD-2, the Carbofuran, Isoprocarb, Methomyl, Metolcarb, and Thiodicarb were stable for a 28-day storage test, Carbaryl and Oxamyl for 14 days, and Methiocarb and Prpoxur for 7 days. All of these pesticides were with detection limit of 3mugm(-3). It is suited for environmental monitoring. The airborne carbamates in different areas of the manufactory were measured.

  3. Study of two-dimensional liquid chromatography with high temperature NPLC and room temperature RPLC

    Institute of Scientific and Technical Information of China (English)

    Hongzhe TIAN; Jing XU; Kun DING; Yafeng GUAN

    2009-01-01

    To overcome the peak band broadening and to increase the peak capacity and separation efficiency of a two-dimensional liquid chromatographic system, a high-temperature normal phase liquid chromatography (HTNPLC) was used as the first dimension (lst-D), and a RPLC was used as the second dimension (2nd-D). The sample was first separated on the lst-D CN column and the primary eluent stored in the sampling-loop system alternatively (in HTNPLC × RPLC mode) or selectively (in HTNPLC/RPLC mode) and was then transferred to 2nd-D C18 column for further separation. The resolution and separation efficiency of the systems were greatly improved. The systems were evaluated by analyzing several polycyclic aromatic hydrocarbons and Glycyrrhiza uralensis extract.

  4. Saffron authentication based on liquid chromatography high resolution tandem mass spectrometry and multivariate data analysis.

    Science.gov (United States)

    Rubert, Josep; Lacina, Ondrej; Zachariasova, Milena; Hajslova, Jana

    2016-08-01

    Saffron is one of the oldest and most expensive spices, which is often target of fraudulent activities. In this research, a new strategy of saffron authentication based on metabolic fingerprinting was developed. In the first phase, a solid liquid extraction procedure was optimized, the main aim was to isolate as maximal representation of small molecules contained in saffron as possible. In the second step, a detection method based on liquid chromatography coupled with high-resolution mass spectrometry was developed. Initially, principal component analysis (PCA) revealed clear differences between saffron cultivated and packaged in Spain, protected designation of origin (PDO), and saffron packaged in Spain of unknown origin, labeled Spanish saffron. Afterwards, orthogonal partial least square discriminant analysis (OPLS-DA) was favorably used to discriminate between Spanish saffron. The tentative identification of markers showed glycerophospholipids and their oxidized lipids were significant markers according to their origin. PMID:26988494

  5. 全自动加压溶剂萃取——高效液相色谱法测定洋葱中芦丁和槲皮素含量%Determination of Contents of Rutin and Quercetin in Onion by Automated Pressurized Liquid Extractor and High Performance Liquid Chromatography

    Institute of Scientific and Technical Information of China (English)

    刘新艳; 张延国; 邹积鑫; 徐东辉; 李凌云; 刘肃

    2011-01-01

    通过与水浴回流法比较,建立了全自动加压溶剂萃取法,可简单、快速测定洋葱中保健活性物质芦丁和槲皮素含量.采用高效液相色谱仪在368nm波长处测定芦丁和槲皮素含量.色谱柱为C18柱,流动相为甲醇-磷酸溶液(58:42,体积比),以1.0ml/min流速等度洗脱,外标法定量.结果表明,在芦丁和槲皮素质量浓度为0.1~200mg/L时,其线性相关系数均大于0.999.在2.0~100mg/kg的添加水平下,芦丁和槲皮素的平均回收率分别为83.5%~94_2%和84.8%~91.2%;相对标准偏差分别为2.9%~7.4%和4.2%~6.9%(n=6).全自动加压溶剂萃取法的检出限(LOD),芦丁和槲皮素分别为0.05,0.03mg/kg.定量限(LOQ),芦丁和槲皮素分别为0.2,0.1mg/kg.研究建立的运用全自动加压溶剂萃取仪提取、高效液相色谱测定洋葱中芦丁和槲皮素的方法,线性良好,重现性较好,灵敏度较高,能够满足蔬菜和水果等农产品中芦丁和槲皮素的快速检测.%As compared with the water circumfluence method, a simple and rapid method was developed for the determination of contents of rutin and quercetin in onion by Automated Pressurized Liquid Extractor (APLE).The contents of rutin and quercetin were first determined by High Performance Liquid Chromatography (HPLC) in 368nm and analyzed on the C18 column by a isocratic elution,using a mixture of methanol~phosphoric acid solution (58:42, V/V) as the mobile phase with a flow rate of 1.0mL/min.The method is calibrated by an external standard method.Under the optimal conditions, the correlation coefficient of rutin and quercetin in the concentration range of 0.1~200mg/L is more than 0.999.The average recovery rates of rutin and quercetin in the spiked range of 2.0~100mg/kg are 83.5%~94.2% and 84.8%~91.2%, respectively.And the relative standard deviations are 2.9%~7.4% and 4.2%~6.9%,respectively (n=6).Using the automated pressurized liquid extractor method, the

  6. Ultrasound-assisted ionic liquid-based homogeneous liquid-liquid microextraction high-performance liquid chromatography for determination of tanshinones in Salvia miltiorrhiza Bge. root.

    Science.gov (United States)

    Wang, Zhibing; Cao, Bocheng; Yu, Aimin; Zhang, Hanqi; Qiu, Fangping

    2015-02-01

    The ultrasound-assisted ionic liquid-based homogeneous liquid-liquid microextraction has been developed and applied to the extraction of four tanshinones, including dihydrotanshinone, tanshinone I, cryptotanshinone and tanshinone IIA in Salvia miltiorrhiza Bge. root. High performance liquid chromatography was applied to the separation and determination of the analytes. The ionic liquid was used as extraction solvent and target analytes were extracted with help of ultrasound. Then, ion-pairing agent was added into the sample solution, which resulted in the formation of water-insoluble ionic liquid in the solution. The phase separation was performed by centrifugation. The extraction, concentration and purification of target analytes were performed simultaneously. The experimental parameters, including type and volume of ionic liquid, sample amount, the size of sample particle, pH value of extraction medium, extraction temperature, extraction time, amount of ion-pairing agent and centrifuging time, were investigated and optimized. The calibration curves showed good linear relationship (r>0.9997). The limits of detection and quantification were in the range of 0.052-0.093 and 0.17-0.31 μg mL(-1), respectively. The recoveries were between 70.45% and 94.23% with relative standard deviations lower than 5.31%. The present method is free of volatile organic solvents, and represents lower expenditures of sample, extraction time and solvent, compared with UAE and HRE. There was no obvious difference in the extraction yields of active constitutions obtained by the three extraction methods. PMID:25497891

  7. Characterization of the chemical composition of a block copolymer by liquid chromatography/mass spectrometry using atmospheric pressure chemical ionization and electrospray ionization

    NARCIS (Netherlands)

    Leeuwen, van Suze M.; Tan, BoonHua; Grijpma, Dirk W.; Feijen, J.; Karst, Uwe

    2007-01-01

    Liquid chromatography/mass spectrometry (LC/MS) with electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) in the positive and negative ion modes was used for the characterization of a block copolymer consisting of methoxy poly(ethylene oxide) (mPEO), an -caprolactone (CL

  8. Characterization of the chemical composition of a block copolymer by liquid chromatography/mass spectrometry using atmospheric pressure chemical ionization and electrospray ionization

    NARCIS (Netherlands)

    van Leeuwen, Suze M.; Tan, BoonHua; Grijpma, Dirk W.; Fejen, Jan; Karst, Uwe

    2007-01-01

    Liquid chromatography/mass spectrometry (LC/MS) with electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) in the positive and negative ion modes was used for the characterization of a block copolymer consisting of methoxy poly(ethylene oxide) (mPEO), an epsilon-caprolact

  9. A new liquid chromatography - tandem mass spectrometry method using atmospheric pressure photo ionization for the simultaneous determination of azaarenes and azaarones in Dutch river sediments

    NARCIS (Netherlands)

    J. Brulik; Z. Simek; P. de Voogt

    2013-01-01

    A new method for the analysis of azaarenes and their degradation products (azaarones) was developed, optimized and validated using liquid chromatography coupled with atmospheric pressure photo ionization tandem mass spectrometric detection (LC-APPI/MS/MS). Seventeen compounds including 4 PAHs (napht

  10. Hb A1c Separation by High Performance Liquid Chromatography in Hemoglobinopathies

    Directory of Open Access Journals (Sweden)

    Vani Chandrashekar

    2016-01-01

    Full Text Available Hb A1c measurement is subject to interference by hemoglobin traits and this is dependent on the method used for determination. In this paper we studied the difference between Hb A1c measured by HPLC in hemoglobin traits and normal chromatograms. We also studied the correlation of Hb A1c with age. Hemoglobin analysis was carried out by high performance liquid chromatography. Spearman’s rank correlation was used to study correlation between A1c levels and age. Mann-Whitney U test was used to study the difference in Hb A1c between patients with normal hemoglobin and hemoglobin traits. A total of 431 patients were studied. There was positive correlation with age in patients with normal chromatograms only. No correlation was seen in Hb E trait or beta thalassemia trait. No significant difference in Hb A1c of patients with normal chromatograms and patients with hemoglobin traits was seen. There is no interference by abnormal hemoglobin in the detection of A1c by high performance liquid chromatography. This method cannot be used for detection of A1c in compound heterozygous and homozygous disorders.

  11. Rapid identification of micro-constituents in monoammonium glycyrrhizinate raw materials by high-pressure solid phase extraction-high performance liquid chromatography-mass spectrometry%高压固相萃取-高效液相色谱-质谱法快速鉴定甘草酸单铵原料中的微量成分

    Institute of Scientific and Technical Information of China (English)

    杨学东; 唐绪岩; 桑琳

    2012-01-01

    Objective:To establish a method for rapid identification of micro-constituents in monoammonium glycyrrhizinate by high-pressure solid phase extraction-high performance liquid chromatography-mass spectrometry. Method; HPLC preparative chromato-graph was adopted for determining the optimal method for high-pressure solid phase extraction under optimal conditions. 5C18MS-II column (20. 0 mm x20. 0 mm) was used as the extraction column, with 35% acetonitrile-acetic acid solution (pH 2. 20) as eluent at the speed of 16 mL min~ . The sample size was 0. 5 mL, and the extraction cycle was 4. 5 min. Then, extract liquid was analyzed by high performance liquid chromatography-mass spectrometry ( HPLC-MS) after being concentrated by 100 times. Result: Under the optimal condition of high-pressure solid phase extraction-high performance liquid chromatography-mass spectrometry, 10 components were rapidly identified from monoammonium glycyrrhizinate raw materials. Among them, the chemical structures of six micro-constituents were identified as 3-O-[β-D-glucuronopyranosyl-β-D)-glucuronopyranosyl ] -30-O-β-D-apiopyranosylglycynhetic/3-O-[β-D)-glucuroriopy-ranosyl-β-D-glueuronopyranosyl] -30-O-β-D-arabinopyranosylglycyrrhetic, glycyrrhizic saponin F3 , 22-hydroxyglyeyrrhizin/18α-glycyr-rhizic saponin G2, 3-0-[β-D-rhamnopyranosyl]-24-hydroxyglycyrrhizin, glycyrrhizic saponin J2, and glycyrrhizic saponin B2 by MS" spectra analysis and reference to literatures. Four main chemical components were identified as glycyrrhizic saponin G2, 18β-glycyrrhi-zic acid, uralglycyrrhizic saponin B and 18α-glycyrrhizic acid by liquid chromatography, MSn and ultraviolet spectra information and comparison with reference substances. Conclusion: The method can be used to identify chemical constituents in monoammonium glycyrrhizinate quickly and effectively, without any reference substance, which provides basis for quality control and safe application of monoammonium glycyrrhizinate

  12. [Simultaneous determination of pantothenic acid and D-panthenol in cosmetics by high performance liquid chromatography].

    Science.gov (United States)

    Mao, Xiqin; Hu, Xia; Pan, Wei

    2010-11-01

    A high performance liquid chromatographic method (HPLC) and sample pretreatment method were developed for the simultaneous determination of pantothenic acid (vitamin B5) and D-panthenol (provitamin B5) in cosmetics with different matrices (including of creams, lotions, aqueous cosmetics, oily cosmetics, wax-based cosmetics, nail polish etc). A liquid-liquid extraction system composed of water and water-immiscible solvent was used to preliminarily separate the target components from other oil-soluble components and surfactants in cosmetics, then macromolecular water-soluble matrices in cosmetics were removed by coprecipitation with potassium ferrocyanide-zinc acetate precipitating agent, and then under acid condition, pantothenic acid and D-panthenol were enriched on a C18 solid-phase extraction sorbent. After the removal of other water-soluble impurities, target components were eluted by 40% methanol and then separated and quantitatively analyzed by high performance liquid chromatography with external standard method. Good linear relationship was achieved in the concentration range of 0.1-10 microg/g for pantothenic acid and D-panthenol. The linear correlation coefficients were separately 0.998 9 and 0.999 6. The average recoveries of the target components in cosmetics were more than 90%. Limit of detection of the method was 30 microg/g and the limit of quantification was 100 microg/g. This method can be used to simultaneously determine pantothenic acid and D-panthenol in cosmetics. The results are accurate and reliable. PMID:21381423

  13. Determination of furanochromones and pyranocoumarins in drugs and Ammi visnaga fruits by combined solid-phase extraction-high-performance liquid chromatography and thin-layer chromatography-high-performance liquid chromatography.

    Science.gov (United States)

    Zgórka, G; Dragan, T; Głowniak, K; Basiura, E

    1998-02-27

    A new, simple and rapid solid-phase extraction method for the determination of furanochromones and pyranocoumarins in Ammi visnaga L. fruits and pharmaceuticals by reversed-phase high-performance liquid chromatography (RP-HPLC) was developed. The isolation of compounds examined was carried out on octadecyl BakerBond SPE columns using various concentrations of methanol, acetonitrile and tetrahydrofuran in water. High and reproducible recoveries were obtained. To compare the results of quantitative analysis a preparative TLC procedure was also elaborated and carried out.

  14. Chromatographic behavior of small organic compounds in low-temperature high-performance liquid chromatography using liquid carbon dioxide as the mobile phase.

    Science.gov (United States)

    Motono, Tomohiro; Nagai, Takashi; Kitagawa, Shinya; Ohtani, Hajime

    2015-07-01

    Low-temperature high-performance liquid chromatography, in which a loop injector, column, and detection cell were refrigerated at -35ºC, using liquid carbon dioxide as the mobile phase was developed. Small organic compounds (polyaromatic hydrocarbons, alkylbenzenes, and quinones) were separated by low-temperature high-performance liquid chromatography at temperatures from -35 to -5ºC. The combination of liquid carbon dioxide mobile phase with an octadecyl-silica (C18 ) column provided reversed phase mode separation, and a bare silica-gel column resulted in normal phase mode separation. In both the cases, nonlinear behavior at approximately -15ºC was found in the relationship between the temperature and the retention factors of the analytes (van't Hoff plots). In contrast to general trends in high-performance liquid chromatography, the decrease in temperature enhanced the separation efficiency of both the columns.

  15. Ionic-liquid-based dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography for the forensic determination of methamphetamine in human urine.

    Science.gov (United States)

    Wang, Ruifeng; Qi, Xiujuan; Zhao, Lei; Liu, Shimin; Gao, Shuang; Ma, Xiangyuan; Deng, Youquan

    2016-07-01

    Determination of methamphetamine in forensic laboratories is a major issue due to its health and social harm. In this work, a simple, sensitive, and environmentally friendly method based on ionic liquid dispersive liquid-liquid microextraction combined with high-performance liquid chromatography was established for the analysis of methamphetamine in human urine. 1-Octyl-3-methylimidazolium hexafluorophosphate with the help of disperser solvent methanol was selected as the microextraction solvent in this process. Various parameters affecting the extraction efficiency of methamphetamine were investigated systemically, including extraction solvent and its volume, disperser solvent and its volume, sample pH, extraction temperature, and centrifugal time. Under the optimized conditions, a good linearity was obtained in the concentration range of 10-1000 ng/mL with determination coefficient >0.99. The limit of detection calculated at a signal-to-noise ratio of 3 was 1.7 ng/mL and the relative standard deviations for six replicate experiments at three different concentration levels of 100, 500, and 1000 ng/mL were 6.4, 4.5, and 4.7%, respectively. Meanwhile, up to 220-fold enrichment factor of methamphetamine and acceptable extraction recovery (>80.0%) could be achieved. Furthermore, this method has been successfully employed for the sensitive detection of a urine sample from a suspected drug abuser. PMID:27135774

  16. Pressurized liquid extraction-gas chromatography-mass spectrometry analysis of fragrance allergens, musks, phthalates and preservatives in baby wipes.

    Science.gov (United States)

    Celeiro, Maria; Lamas, J Pablo; Garcia-Jares, Carmen; Llompart, Maria

    2015-03-01

    Baby wipes and wet toilet paper are specific hygiene care daily products used on newborn and children skin. These products may contain complexes mixtures of harmful chemicals. A method based on pressurized liquid extraction (PLE) followed by gas chromatography-mass spectrometry (GC-MS) has been developed for the simultaneous determination of sixty-five chemical compounds (fragrance allergens, preservatives, musks, and phthalates) in wipes and wet toilet paper for children. These compounds are legislated in Europe according Regulation EC No 1223/2009, being twelve of them banned for their use in cosmetics, and one of them, 3-iodo-2-propynyl butylcarbamate (IPBC), is banned in products intended for children under 3 years. Also, propyl-, and butylparaben will be prohibited in leave-on cosmetic products designed for application on the nappy area of children under 3 years from April 2015. PLE is a fast, simple, easily automated technique, which permits to integrate a clean-up step during the extraction process reducing analysis time and stages. The proposed PLE-based procedure was optimized on real non-spiked baby wipe samples by means of experimental design to study the influence on extraction of parameters such as extraction solvent, temperature, extraction time, and sorbent type. Under the selected conditions, the method was validated showing satisfactory linearity, and intra-day, and inter-day precision. Recoveries were between 80-115% for most of the compounds with relative standard deviations (RSD) lower than 15%. Finally, twenty real samples were analyzed. Thirty-six of the target analytes were detected, highlighting the presence of phenoxyethanol in all analyzed samples at high concentration levels (up to 0.8%, 800μgg(-1)). Methyl paraben (MeP), and ethyl paraben (EtP) were found in 40-50% of the samples, and the recently banned isobutyl paraben (iBuP) and isopropyl paraben (iPrP), were detected in one and seven samples, respectively, at concentrations between

  17. [Simultaneous determination of eight furocoumarines in cosmetics by high performance liquid chromatography and verification by liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Ma, Huijuan; Ma, Qiang; Li, Wentao; Meng, Xianshuang; Li, Jingrui; Bai, Hua; Jiao, Yang; Zhang, Xiaoli

    2013-05-01

    A method using high performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the simultaneous determination of eight furocoumarines (8-hydroxypsoralen, psoralen, isopsoralen, 8-methoxypsoralen, 5-methoxypsoralen, trioxsalen, imperatorin and isoimperatorin) in cosmetics. The cosmetic samples, including cream, lotion, shampoo, powder and lipstick, were supersonically extracted with appropriate solvents. The extract was centrifuged, and the supernatant was filtered through a membrane, and then separated on an Agilent Zorbax SB-Phenyl chromatographic column (250 mm x 4.6 mm, 5 microm) by gradient elution at a flow rate of 1.0 mL/min with methanol-acetonitrile-water as mobile phases. The column temperature was set at 30 degrees C. The wavelength of detection was 250 nm. The limits of quantification (LOQs) were 0.25 mg/kg for 8-hydroxypsoralen and 0.5 mg/kg for psoralen, isopsoralen, 8-methoxypsoralen, 5-methoxypsoralen, trioxsalen, imperatorin and isoimperatorin. The recoveries at three spiked levels were in the range of 85.0% - 105.8% with the relative standard deviations (RSDs) of 0.41% - 7.90%. The intra-day precision (n=6) was less than 1%, and the inter-day precision (n = 6) was less than 2% for the peak areas of the eight furocoumarines in a mixed standard solution. The method is accurate, simple, rapid and suitable for the determination of the eight furocoumarines in various cosmetic samples. PMID:24010339

  18. Discussions about high performance liquid chromatography upgrading to ion chromatography%液相色谱升级改造为离子色谱问题探讨

    Institute of Scientific and Technical Information of China (English)

    施超欧; 马浩; 姚宝龙; 黄彩勇

    2014-01-01

    离子色谱作为色谱的一个分支,在原理和仪器结构上与液相色谱密切相关。本文总结了液相色谱升级为离子改造色谱的经验。%As a part of chromatography ,the functions and structures of instruments between high per-formance liquid chromatography and ion chromatography are closely related .In this paper ,HPLC upgra-ded to IC was discused .

  19. Determination of diflubenzuron and chlorbenzuron in fruits by combining acetonitrile-based extraction with dispersive liquid-liquid microextraction followed by high-performance liquid chromatography.

    Science.gov (United States)

    Ruan, Chunqiang; Zhao, Xiang; Liu, Chenglan

    2015-09-01

    In this study, a simple and low-organic-solvent-consuming method combining an acetonitrile-partitioning extraction procedure followed by "quick, easy, cheap, effective, rugged and safe" cleanup with ionic-liquid-based dispersive liquid-liquid microextraction and high-performance liquid chromatography with diode array detection was developed for the determination of diflubenzuron and chlorbenzuron in grapes and pears. Ionic-liquid-based dispersive liquid-liquid microextraction was performed using the ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate as the extractive solvent and acetonitrile extract as the dispersive solvent. The main factors influencing the efficiency of the dispersive liquid-liquid microextraction were evaluated, including the extractive solvent type and volume and the dispersive solvent volume. The validation parameters indicated the suitability of the method for routine analyses of benzoylurea insecticides in a large number of samples. The relative recoveries at three spiked levels ranged between 98.6 and 109.3% with relative standard deviations of less than 5.2%. The limit of detection was 0.005 mg/kg for the two insecticides. The proposed method was successfully used for the rapid determination of diflubenzuron and chlorbenzuron residues in real fruit samples.

  20. High-Performance Liquid Chromatography Determination of Meloxicam and Piroxicam with Ultraviolet Detection

    Directory of Open Access Journals (Sweden)

    Sherry Cox

    2014-01-01

    Full Text Available A simple accurate and sensitive high-performance liquid chromatographic method for the determination of meloxicam and piroxicam concentrations in small volume plasma samples has been developed. Following a liquid extraction using chloroform, samples were separated by reversed-phase high-performance liquid chromatography on an XBridge C18 column (4.6 × 250 mm and quantified using ultraviolet detection at 360 nm. The mobile phase was a mixture of water with glacial acetic acid (pH 3.0 and acetonitrile (50 : 50, with a flow rate of 1.0 mL/min. The standard curve ranged from 5 to 10,000 ng/mL for meloxicam in bearded dragon (Pogona vitticeps plasma and piroxicam in crane (Grus rubicunda plasma. Intra- and interassay variability for meloxicam and piroxicam were less than 10% and the average recovery was greater than 90% for both drugs. This method was developed in bearded dragon and crane plasma and should be applicable to any species, making it useful for those investigators dealing with small sample volumes, particularly when conducting pharmacokinetics studies which require multiple sampling from the same animal.

  1. Rapid concentration and high pressure liquid chromatographic determination of atrazine and simazine herbicides in water

    International Nuclear Information System (INIS)

    A simple fast method for extracting and concentrating atrazine and simazine in water using C18 sep-pakTm cartridges (Waters Association Inc., Milford, Massachuaetts) and subsequent determination of the herbicides using reversed-phase high pressure liquid chromatography (HPLC) has been developed. A 500 ml water sample containing atrazine and simazine was passed through a C18 sep-pak cartridge and the absorbed herbicides eluted with dichloromethane. After evaporation of the solvent, atrazine and simazine were determined using reversed-phase HPLC. An utraviolet(UV) detector at a wavelength of 230 nm or 254 nm was used to detect two herbicides. Detection limits of 1ppb and 4ppb were reached with the wavelengths 230nm and 254 nm respectively. (author)

  2. Separation of maleic anhydride grafted polypropylene using multidimensional high-temperature liquid chromatography.

    Science.gov (United States)

    Prabhu, K N; Macko, T; Brüll, R; Remerie, K; Tacx, J; Garg, P; Ginzburg, A

    2016-04-01

    Functionalization addresses a property gap of polyolefins and opens new perspectives due to improved surface properties in applications like composites (e.g., glass fiber reinforced polypropylene) and anti-corrosive coatings for metals. Various techniques have been developed to characterize functionalized polyolefins, yet no analytical approach addressing their chemical heterogeneity exists. Using High Temperature Size Exclusion Chromatography (HT-SEC) coupled to infrared spectroscopy we could show for two model samples of polypropylene grafted maleic anhydride (PP-g-MA), differing in their nominal MA content, that the grafting density increases with decreasing molar mass. Crystallization Analysis Fractionation (CRYSTAF) does not enable to separate these samples according to their composition to the extent required. Yet, when using High Temperature High Performance Liquid Chromatography (HT-HPLC), with either silica gel or Mica as stationary phase and a gradient mobile phase, a deformulation into a grafted and a non-grafted fraction could be achieved. This was confirmed by analyzing the eluted fractions by infrared spectroscopy. Hyphenating the separation according to composition with a separation according to molar mass (HT-HPLC x HT-SEC) enabled for the first time to reveal the bivariate distribution of PP-g-MA with regard to the molar mass and composition. Using on-line infrared detection quantitative information on the compositional and molar mass parameters of the individual fractions could be obtained.

  3. Separation of maleic anhydride grafted polypropylene using multidimensional high-temperature liquid chromatography.

    Science.gov (United States)

    Prabhu, K N; Macko, T; Brüll, R; Remerie, K; Tacx, J; Garg, P; Ginzburg, A

    2016-04-01

    Functionalization addresses a property gap of polyolefins and opens new perspectives due to improved surface properties in applications like composites (e.g., glass fiber reinforced polypropylene) and anti-corrosive coatings for metals. Various techniques have been developed to characterize functionalized polyolefins, yet no analytical approach addressing their chemical heterogeneity exists. Using High Temperature Size Exclusion Chromatography (HT-SEC) coupled to infrared spectroscopy we could show for two model samples of polypropylene grafted maleic anhydride (PP-g-MA), differing in their nominal MA content, that the grafting density increases with decreasing molar mass. Crystallization Analysis Fractionation (CRYSTAF) does not enable to separate these samples according to their composition to the extent required. Yet, when using High Temperature High Performance Liquid Chromatography (HT-HPLC), with either silica gel or Mica as stationary phase and a gradient mobile phase, a deformulation into a grafted and a non-grafted fraction could be achieved. This was confirmed by analyzing the eluted fractions by infrared spectroscopy. Hyphenating the separation according to composition with a separation according to molar mass (HT-HPLC x HT-SEC) enabled for the first time to reveal the bivariate distribution of PP-g-MA with regard to the molar mass and composition. Using on-line infrared detection quantitative information on the compositional and molar mass parameters of the individual fractions could be obtained. PMID:26961914

  4. Direct determination of chlorophenols in water samples through ultrasound-assisted hollow fiber liquid-liquid-liquid microextraction on-line coupled with high-performance liquid chromatography.

    Science.gov (United States)

    Chao, Yu-Ying; Tu, Yi-Ming; Jian, Zhi-Xuan; Wang, Hsaio-Wen; Huang, Yeou-Lih

    2013-01-01

    In this study we on-line coupled hollow fiber liquid-liquid-liquid microextraction (HF-LLLME), assisted by an ultrasonic probe, with high-performance liquid chromatography (HPLC). In this approach, the target analytes - 2-chlorophenol (2-CP), 3-chlorophenol (3-CP), 2,6-dichlorophenol (2,6-DCP), and 3,4-dichlorophenol (3,4-DCP) - were extracted into a hollow fiber (HF) supported liquid membrane (SLM) and then back-extracted into the acceptor solution in the lumen of the HF. Next, the acceptor solution was withdrawn on-line into the HPLC sample loop connected to the HF and then injected directly into the HPLC system for analysis. We found that the chlorophenols (CPs) could diffuse quickly through two sequential extraction interfaces - the donor phase - SLM and the SLM - acceptor phase - under the assistance of an ultrasonic probe. Ultrasonication provided effective mixing of the extracted boundary layers with the bulk of the sample and it increased the driving forces for mass transfer, thereby enhancing the extraction kinetics and leading to rapid enrichment of the target analytes. We studied the effects of various parameters on the extraction efficiency, viz. the nature of the SLM and acceptor phase, the compositions of the donor and acceptor phases, the fiber length, the stirring rate, the ion strength, the sample temperature, the sonication conditions, and the perfusion flow rate. This on-line extraction method exhibited linearity (r(2)≥0.998), sensitivity (limits of detection: 0.03-0.05 μg L(-1)), and precision (RSD%≤4.8), allowing the sensitive, simple, and rapid determination of CPs in aqueous solutions and water samples with a sampling time of just 2 min. PMID:23237709

  5. Determination of Alternaria mycotoxins in wine and juice using ionic liquid modified countercurrent chromatography as a pretreatment method followed by high-performance liquid chromatography.

    Science.gov (United States)

    Fan, Chen; Cao, Xueli; Liu, Man; Wang, Wei

    2016-03-01

    Alternariol (AOH), alternariol monomethyl ether (AME), and tenuazonic acid (TeA) are some of the main Alternaria mycotoxins that can be found as contaminants in food materials. The objective of this study was to develop a pretreatment method with countercurrent chromatography (CCC) for enrichment and cleanup of trace Alternaria mycotoxins in food samples prior to high-performance liquid chromatography (HPLC) analysis. An Analytical CCC instrument with a column volume 22.5mL was used, and a two-phase solvent system composed of ethyl acetate and water modified with 6% [HOOMIM][Cl] in mass to volume ratio was selected. Under the optimized CCC operation conditions, trace amounts of AOH, AME, and TeA in large volume of liquid sample were efficiently extracted and enriched in the stationary phase, and then eluted out just by reversing the stationary phase as mobile phase in the opposite flowing direction tail-to-head. The enrichment and elution strategies are unique and can be fulfilled online with high enrichment factors (87-114) and high recoveries (81.14-110.94%). The method has been successively applied to the determination of Alternaria mycotoxins in real apple juice and wine samples with the limits of detection (LOD) in the range of 0.03-0.14μgL(-1). Totally 12 wine samples and 15 apple juice samples from the local market were analyzed. The detection rate of AOH and AME in both kinds of the samples were more than 50%, while TeA was found in relatively high level of 1.75-49.61μgL(-1) in some of the apple juice samples. The proposed method is simple, rapid, and sensitive and could also be used for the analysis and monitoring of Alternaria mycotoxin in other food samples. PMID:26858114

  6. Determination of Alternaria mycotoxins in wine and juice using ionic liquid modified countercurrent chromatography as a pretreatment method followed by high-performance liquid chromatography.

    Science.gov (United States)

    Fan, Chen; Cao, Xueli; Liu, Man; Wang, Wei

    2016-03-01

    Alternariol (AOH), alternariol monomethyl ether (AME), and tenuazonic acid (TeA) are some of the main Alternaria mycotoxins that can be found as contaminants in food materials. The objective of this study was to develop a pretreatment method with countercurrent chromatography (CCC) for enrichment and cleanup of trace Alternaria mycotoxins in food samples prior to high-performance liquid chromatography (HPLC) analysis. An Analytical CCC instrument with a column volume 22.5mL was used, and a two-phase solvent system composed of ethyl acetate and water modified with 6% [HOOMIM][Cl] in mass to volume ratio was selected. Under the optimized CCC operation conditions, trace amounts of AOH, AME, and TeA in large volume of liquid sample were efficiently extracted and enriched in the stationary phase, and then eluted out just by reversing the stationary phase as mobile phase in the opposite flowing direction tail-to-head. The enrichment and elution strategies are unique and can be fulfilled online with high enrichment factors (87-114) and high recoveries (81.14-110.94%). The method has been successively applied to the determination of Alternaria mycotoxins in real apple juice and wine samples with the limits of detection (LOD) in the range of 0.03-0.14μgL(-1). Totally 12 wine samples and 15 apple juice samples from the local market were analyzed. The detection rate of AOH and AME in both kinds of the samples were more than 50%, while TeA was found in relatively high level of 1.75-49.61μgL(-1) in some of the apple juice samples. The proposed method is simple, rapid, and sensitive and could also be used for the analysis and monitoring of Alternaria mycotoxin in other food samples.

  7. The use of ultra high-performance liquid chromatography for studying hydrolysis kinetics of CL-20 and related energetic compounds.

    Science.gov (United States)

    Makarov, Alexey; Lobrutto, Rosario; Christodoulatos, Christos; Jerkovich, Anton

    2009-03-15

    Ultra high-performance liquid chromatography (UHPLC) utilizes columns packed with sub-2-mum stationary-phase particles and allows operation with pressures of up to 15,000 psi to yield increased resolution, speed, and sensitivity versus conventional HPLC. This promising new technology was used for the analysis of energetic compounds (RDX, HMX and CL-20) and a selective method was developed on an Acquity UPLC. A fast UHPLC method was applied to determine alkaline hydrolysis reaction kinetics of major energetic compounds. Activation energies of alkaline hydrolysis reaction for CL-20, RDX and HMX were comparable to those in literature, however they were determined in a shorter amount of time due to the speed of analysis of the chromatographic method. The use of liophilic salts (KPF(6)) as mobile-phase additives for the enhancement of separation selectivity of energetic compounds was demonstrated. PMID:18644671

  8. Rapid determination of alpha tocopherol in olive oil adulterated with sunflower oil by reversed phase high-performance liquid chromatography.

    Science.gov (United States)

    Bakre, S M; Gadmale, D K; Toche, R B; Gaikwad, V B

    2015-05-01

    A new method is developed to determine the presence of sunflower oil in olive oil. α-tocopherol is selected as discriminating parameter for detecting sunflower oil adulterant in olive oil. Admixtures of olive oil and sunflower oil (5 %, 10 %, 15 % and 20 % sunflower oil in olive oil) are prepared. These admixtures are analysed by reversed phase high pressure liquid chromatography coupled with fluorescence detector. The sample preparation does not require saponification or addition of antioxidant. The chromatographic system consists of a C18 column with methanol: acetonitrile (50:50) mobile phase. Fluorescence detector excitation wavelength is set at 290 nm and emission wavelength is set at 330 nm. The α tocopherol concentration increases linearly in olive oil adulterated with sunflower oil. The method is simple, selective, sensitive and is precise (RSD = 2.65 %) for α tocopherol. The present method can precisely detect 5 % sunflower oil in olive oil.

  9. High Performance Thin Layer Chromatography.

    Science.gov (United States)

    Costanzo, Samuel J.

    1984-01-01

    Clarifies where in the scheme of modern chromatography high performance thin layer chromatography (TLC) fits and why in some situations it is a viable alternative to gas and high performance liquid chromatography. New TLC plates, sample applications, plate development, and instrumental techniques are considered. (JN)

  10. Purification of six lignans from the stems of Schisandra chinensis by using high-speed counter-current chromatography combined with preparative high-performance liquid chromatography.

    Science.gov (United States)

    Zhu, Lijie; Li, Bin; Liu, Xiuying; Huang, Guohui; Meng, Xianjun

    2015-11-01

    A method for the preparative purification of lignans from Schisandra chinensis was established using a combination of high-speed counter-current chromatography (HSCCC) and preparative high-performance liquid chromatography (HPLC). The crude extracts obtained from S. chinensis by using 70% ethanol were separated on a macroporous resin column and then eluted with a graded ethanol series. A two-phase solvent system consisting of n-hexane-ethyl acetate-methanol-water (1:1:1:1, v/v) was used for HSCCC, and a mobile phase of acetonitrile-water (50:50, v/v) was used for preparative HPLC. The results obtained using HSCCC were compared with those obtained using preparative HPLC, and their advantages were further integrated to improve the separation efficiency. Six known lignans were identified by electrospray ionisation mass spectrometry and (1)H nuclear magnetic resonance (NMR) and (13)C NMR analyses; the purities of all the compounds were more than 91%.

  11. Separation of three anthraquinone glycosides including two isomers by preparative high-performance liquid chromatography and high-speed countercurrent chromatography from Rheum tanguticum Maxim. ex Balf.

    Science.gov (United States)

    Chen, Tao; Li, Hongmei; Zou, Denglang; Liu, Yongling; Chen, Chen; Zhou, Guoying; Li, Yulin

    2016-08-01

    Anthraquinone glycosides, such as chrysophanol 1-O-β-d-glucoside, chrysophanol 8-O-β-d-glucoside, and physion 8-O-β-d-glucoside, are the accepted important active components of Rheum tanguticum Maxim. ex Balf. due to their pharmacological properties: antifungal, antimicrobial, cytotoxic, and antioxidant activities. However, an effective method for the separation of the above-mentioned anthraquinone glycosides from this herb is not currently available. Especially, greater difficulty existed in the separation of the two isomers chrysophanol 1-O-β-d-glucoside and chrysophanol 8-O-β-d-glucoside. This study demonstrated an efficient strategy based on preparative high-performance liquid chromatography and high-speed countercurrent chromatography for the separation of the above-mentioned anthraquinone glycosides from Rheum tanguticum Maxim.ex Balf.

  12. Determination of Polycyclic Aromatic Hydrocarbons in Automobile Exhaust by Means of High-Performance Liquid Chromatography with Fluorescence Detection

    DEFF Research Database (Denmark)

    Nielsen, Tom

    1979-01-01

    A chromatographic method has been developed and applied to the determination of polycyclic aromatic hydrocarbons (PAHs) in particulate matter in automobile exhaust, in petrols, and in crankcase oils. The PAHs were purified from other organic compounds by thin-layer chromatography, separated by high-performance...... liquid chromatography, and measured by means of on-line fluorescence detection. The identities of the PAHs were verified by comparing the emission spectra obtained by a stop-flow technique with those of standard PAHs...

  13. Anion-exchange high-performance liquid chromatography with conductivity detection for the analysis of phytic acid in food

    OpenAIRE

    Talamond, Pascale; Doulbeau, Sylvie; Rochette, Isabelle; Guyot, Jean-Pierre; Trèche, Serge

    1999-01-01

    A sensitive method for the accurate determination of phytic acid in food samples is described. The proposed procedure involves the anion-exchange liquid chromatography with conductivity detection. Initially, two methods of determination of phytic acid were compared : absorptiometry and high-performance ion chromatography (HPIC) with chemically suppressed conductivity detector. Unlike most conventional methods involving precipitation by FeCl3, the simpler and more reliable HPIC assay avoids th...

  14. Determination of Harmine and Harmaline in Peganum harmala Seeds by High-Performance Liquid Chromatography

    Science.gov (United States)

    Monsef-Esfahani, Hamid Reza; Faramarzi, Mohammad Ali; Mortezaee, Venus; Amini, Mohsen; Rouini, Mohammad Reza

    A High-Performance Liquid Chromatography (HPLC) method was developed for determination of harmine, harmaline, harmol and harmalol in the extract of Peganum harmala seeds. The sample preparation was performed using liquid-liquid extraction. Chromatographic separation was achieved with a Tracer Excel 120 ODSA (150x4.6 mm) column, using a mixture of potassium phosphate buffer (10 mM, pH 7.0): acetonitrile (100:30; v/v) as mobile phase, in an isocratic mode at 1.5 mL min-1. UV detection (λ = 330 nm) was used. The calibration curves were linear (r2>0.998) in the concentration range of 0.5-20 μg mL-1 for all analytes. The lower limit of quantification for all analytes was 0.5 μg mL-1. The within and between day precisions in the measurement of QC samples at three tested concentrations were in the range of 0.6-10.2% for all analytes. The HPLC method is able to measure the harmala alkaloids in the plant extract. The method has suitable reproducibility, sensitivity and resolution for routine and accurate use with UV detection.

  15. High-performance liquid chromatography separation of unsaturated organic compounds by a monolithic silica column embedded with silver nanoparticles.

    Science.gov (United States)

    Zhu, Yang; Morisato, Kei; Hasegawa, George; Moitra, Nirmalya; Kiyomura, Tsutomu; Kurata, Hiroki; Kanamori, Kazuyoshi; Nakanishi, Kazuki

    2015-08-01

    The optimization of a porous structure to ensure good separation performances is always a significant issue in high-performance liquid chromatography column design. Recently we reported the homogeneous embedment of Ag nanoparticles in periodic mesoporous silica monolith and the application of such Ag nanoparticles embedded silica monolith for the high-performance liquid chromatography separation of polyaromatic hydrocarbons. However, the separation performance remains to be improved and the retention mechanism as compared with the Ag ion high-performance liquid chromatography technique still needs to be clarified. In this research, Ag nanoparticles were introduced into a macro/mesoporous silica monolith with optimized pore parameters for high-performance liquid chromatography separations. Baseline separation of benzene, naphthalene, anthracene, and pyrene was achieved with the theoretical plate number for analyte naphthalene as 36,000 m(-1). Its separation function was further extended to cis/trans isomers of aromatic compounds where cis/trans stilbenes were chosen as a benchmark. Good separation of cis/trans-stilbene with separation factor as 7 and theoretical plate number as 76,000 m(-1) for cis-stilbene was obtained. The trans isomer, however, is retained more strongly, which contradicts the long- established retention rule of Ag ion chromatography. Such behavior of Ag nanoparticles embedded in a silica column can be attributed to the differences in the molecular geometric configuration of cis/trans stilbenes.

  16. Determination of triazine herbicides in milk by cloud point extraction and high-performance liquid chromatography.

    Science.gov (United States)

    Liu, Tiantian; Cao, Peng; Geng, Jinpei; Li, Jinqiang; Wang, Mingzhen; Wang, Minglin; Li, Xiaoyu; Yin, Dalu

    2014-01-01

    High-performance liquid chromatography with UV detection was used to detect four triazines in milk. An efficient pretreatment method known as cloud point extraction (CPE) was proposed for extracting and preconcentrating analytes. The parameters of CPE including surfactant type and concentration, electrolyte, sample pH, incubation temperature and duration were investigated. Under optimal conditions, satisfying recoveries in the range of 70.5-96.9% were achieved for four triazines. The limits of detection ranged from 6.79 to 11.19μg L(-1). The linear range of quantitation for the four triazines was 50-2000μg L(-1), and the correlation coefficients of the calibration curves were all 0.9999. The results demonstrated that the proposed method was efficient and reliable for the determination of triazine herbicides in milk samples.

  17. Determination of free urinary cortisol in cushing's syndrome using reversed-phase high performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Eduardo Kinio Sugawara

    2010-01-01

    Full Text Available Determination of free urinary cortisol is a test of choice in the diagnosis of Cushing's syndrome. In this study, cortisol was quantified using reversed-phase high-performance liquid chromatography (RP-HPLC in urine samples previously extracted with ether and using triamcinolone acetonide as internal standard (IS. A BDS-Hypersil-C18® column, water-acetonitrile (72:28; v/v, with a flow rate of 1.0 mL/min and detection at 243 nm were used. This method showed to be both effective and efficient, with sensitivity and linearity ranging from 2.50 to 150 μg/L, and can be used in substitution to the radioimmunoassay technique within this concentration range.

  18. Simultaneous Determination of Five Components Including Acetaminophen by Reversed-phase High Performance Liquid Chromatography

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li-qing; WU Xiao-hua; LU Ying; WANG Xia

    2004-01-01

    High performance liquid chromatography with a C18 reverse-phase column was used to separatethe five components in cough syrup, including acetaminophen, p-aminophenol, caffeine, chlorphenamine maleateand guaifenesin. The mobile phase consists of 15wi% acetonitrile, 0.004mol/L sodium heptyl sulfonate,0.03 mole/L potassium di- hydrogen phosphate and triethylamine ( volume ratio 13: 40: 44: 3), the pH of which isadjusted to 3.0 by phosphoric acid. The contents of the five components are analyzed on an ultraviolet spectropho-tometer at 254nm, with a flow rate of 0.4mL/min. The results show that the calibration curves are linear in acertain range. The average recovery of five components is between 96.31% and 102.3% .

  19. High-performance liquid chromatography for determination of α-tocopherol in vegetables

    Directory of Open Access Journals (Sweden)

    Marcin Horbowicz

    2013-12-01

    Full Text Available A simple method for the determination of α-tocopherol in vegetables is described. The procedure consists of the following steps: saponification, extraction, silica-column clean-up, and high-performance liquid chromatography. Elution time for D, L-α-tocopherol was 9.0 min using a Zorbax Sil (250 x 4.6 mm column and an isocratic mobile phase of hexane-methanol (99.3 + 0.7, with a flow rate of 1 ml/min, and detection at 292 nm using a variable UV detector. The average recovery of α-tocopherol was 91.2%, and the minimum detectable amount was 0.1 mg/100 g of fresh vegetable tissue. This method is comparable to gas-chromatographic determination of α-tocopherol, but has fewer analytical steps and gives more reproducible results.

  20. [Analysis of amines in water samples by high performance liquid chromatography-laser induced fluorescence detection].

    Science.gov (United States)

    Liu, Fan; Gao, Fangyuan; Tang, Tao; Sun, Yuanshe; Li, Tong; Zhang, Weibing

    2013-11-01

    A sensitive high performance liquid chromatography (HPLC)-laser induced fluorescence detection (LIFD) method was developed for the determination of amines. The derivatization and separation conditions were investigated. Under the optimized conditions, spermidine, putrescine and histamine were analyzed. The limits of detection (LODs) of the three biogenic amines (S/N = 3) were as low as 10(-10) mol/L. This method showed excellent stability. The RSDs of retention times and peak areas of the three biogenic amines were lower than 0.3% and 3%, respectively. This method was applied in biogenic amine analysis in water samples, and the average recoveries were in the range of 94.99%-104.7%. Furthermore, the amines in seven tea samples were analyzed by this method, and satisfactory results were achieved. The developed assay is of excellent sensitivity and good reproducibility, which can be used in the analysis of the amines in water samples. PMID:24558849

  1. Postcolumn photolysis of pesticides for fluorometric determination by high-performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Miles, C.J.; Moye, H.A.

    1988-02-01

    A high-performance liquid chromatography postcolumn reaction detector that employs UV photolysis with an optional reaction by using o-phthalaldehyde-2-mercaptoethanol (OPA-MERC) followed by fluorescence detection was found to be useful for several classes of pesticides. In the presence of the OPA-MERC reagent, most carbamates, carbamoyl oximes, carbamothioic acids, and substituted ureas gave a sensitive response while the response of dithiocarbamates, phenylamides, and phenylcarbamates varied. The response of most of the pesticides tested was significantly affected by the solvent used. Method detection limits for aldicarb sulfoxide, aldicarb, propoxur, thiram, and neburon in ground water were 2.5, 2.3, 3.3, 3.8, and 2.0 ..mu..g/L, respectively. In the absence of OPA-MERC reagent, several of the substituted aromatic compounds also gave strong fluorescence after photolysis. This detector is applicable to a broad range of nitrogenous pesticides.

  2. A high performance liquid chromatography method for determination of furfural in crude palm oil.

    Science.gov (United States)

    Loi, Chia Chun; Boo, Huey Chern; Mohammed, Abdulkarim Sabo; Ariffin, Abdul Azis

    2011-09-01

    A modified steam distillation method was developed to extract furfural from crude palm oil (CPO). The collected distillates were analysed using high performance liquid chromatography (HPLC) coupled with an ultraviolet diode detector at 284nm. The HPLC method allowed identification and quantification of furfural in CPO. The unique thermal extraction of CPO whereby the fresh fruit bunches (FFB) are first subjected to steam treatment, distinguishes itself from other solvent-extracted or cold-pressed vegetable oils. The presence of furfural was also determined in the fresh palm oil from FFB (without undergoing the normal extraction process), palm olein, palm stearin, olive oil, coconut oil, sunflower oil, soya oil and corn oil. The chromatograms of the extracts were compared to that of standard furfural. Furfural was only detected in CPO. The CPO consignments obtained from four mills were shown to contain 7.54 to 20.60mg/kg furfural.

  3. Analysis of lipophilic pigments from a phototrophic microbial mat community by high performance liquid chromatography

    Science.gov (United States)

    Palmisano, A. C.; Cronin, S. E.; Des Marais, D. J.

    1988-01-01

    As assay for lipophilic pigments in phototrophic microbial mat communities using reverse phase-high performance liquid chromatography was developed which allows the separation of 15 carotenoids and chloropigments in a single 30 min program. Lipophilic pigments in a laminated mat from a commercial salina near Laguna Guerrero Negro, Baja California Sur, Mexico reflected their source organisms. Myxoxanthophyll, echinenone, canthaxanthin, and zeaxanthin were derived from cyanobacteria; chlorophyll c, and fucoxanthin from diatoms; chlorophyll a from cyanobacteria and diatoms; bacteriochlorophylls a and c, bacteriophaeophytin a, and gamma-carotene from Chloroflexus spp.; and beta-carotene from a variety of phototrophs. Sensitivity of detection was 0.6-6.1 ng for carotenoids and 1.7-12 ng for most chloropigments. This assay represents a significant improvement over previous analyses of lipophilic pigments in microbial mats and promises to have a wider application to other types of phototrophic communities.

  4. Determination of Sex Hormones in Antler Velvet by High Performance Liquid Chromatography Tandem Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    LU Chun-mei; WANG Ming-tai; MU Jun; BAI Yu-ping; DU Jian-shi; ZHANG Han-qi; WANG Jian-wei

    2012-01-01

    Eighteen sex hormones in antler velvet were determined by high performance liquid chromatography tandem mass spectrometry.The solid phase extraction was applied to eliminating the matrix effect.The experimental conditions were examined and optimized.Under the optimal conditions,the proposed method provides the good linearities and determination limits(0.2-1.0 μg/kg)of the analytes investigated.The recoveries ranging from 72.3% to 149.5% were obtained for the target analytes at two concentration levels.This method was applied to the determination of eighteen sex hormones in different kinds of antler velvet samples and the obtained results are satisfactory.The results indicate that the proposed method is suitable for the determination of sex hormones in antler velvet samples.

  5. A validated new method for nevirapine quantitation in human plasma via high-performance liquid chromatography.

    Science.gov (United States)

    Silverthorn, Courtney F; Parsons, Teresa L

    2006-01-01

    A fully validated and clinically relevant assay was developed for the assessment of nevirapine concentrations in neonate blood plasma samples. Solid-phase extraction with an acid-base wash series was used to prepare subject samples for analysis. Samples were separated by high performance liquid chromatography and detected at 280 nm on a C8 reverse-phase column in an isocratic mobile phase. The retention times of nevirapine and its internal standard were 5.0 and 6.9 min, respectively. The method was validated by assessment of accuracy and precision (statistical values 0.996) and the average recovery was 93% (n = 18). The lower limit of quantification (relative standard deviation <20%) was determined to be 25 ng/mL for 50 microL of plasma, allowing detection of as little as 1.25 ng of nevirapine in a sample. This value represents an increase in sensitivity of up to 30-fold over previously published methods.

  6. Ultrapreconcentration and determination of organophosphorus pesticides in water by solid-phase extraction combined with dispersive liquid-liquid microextraction and high-performance liquid chromatography.

    Science.gov (United States)

    Chen, Junhua; Zhou, Guangming; Deng, Yongli; Cheng, Hongmei; Shen, Jie; Gao, Yi; Peng, Guilong

    2016-01-01

    Solid-phase extraction coupled with dispersive liquid-liquid microextraction was developed as an ultra-preconcentration method for the determination of four organophosphorus pesticides (isocarbophos, parathion-methyl, triazophos and fenitrothion) in water samples. The analytes considered in this study were rapidly extracted and concentrated from large volumes of aqueous solutions (100 mL) by solid-phase extraction coupled with dispersive liquid-liquid microextraction and then analyzed using high performance liquid chromatography. Experimental variables including type and volume of elution solvent, volume and flow rate of sample solution, salt concentration, type and volume of extraction solvent and sample solution pH were investigated for the solid-phase extraction coupled with dispersive liquid-liquid microextraction with these analytes, and the best results were obtained using methanol as eluent and ethylene chloride as extraction solvent. Under the optimal conditions, an exhaustive extraction for four analytes (recoveries >86.9%) and high enrichment factors were attained. The limits of detection were between 0.021 and 0.15 μg/L. The relative standard deviations for 0.5 μg/L of the pesticides in water were in the range of 1.9-6.8% (n = 5). The proposed strategy offered the advantages of simple operation, high enrichment factor and sensitivity and was successfully applied to the determination of four organophosphorus pesticides in water samples.

  7. Quantitative profiling of retinyl esters in milk from different ruminant species by using high performance liquid chromatography-diode array detection-tandem mass spectrometry.

    Science.gov (United States)

    Rocchi, Silvia; Caretti, Fulvia; Gentili, Alessandra; Curini, Roberta; Perret, Daniela; Pérez-Fernández, Virginia

    2016-11-15

    An effective high performance liquid chromatography-diode array detection-tandem mass spectrometry (HPLC-DAD-MS/MS) analytical approach was developed for retinoid profiling in raw milk samples (cow, buffalo, ewe, and goat). The analytes were isolated by means of liquid-liquid extraction, including a "lipid freezing" step, with yields exceeding 66%. Since the positive atmospheric pressure chemical ionisation mass spectrometry (APCI-MS) detection is not completely selective, a reliable identification has been accomplished by fully separating the analytes on a tandem C18/C30 column system under non-aqueous reversed phase (NARP) chromatography conditions. After validation, different milk varieties obtained from pasture-fed animals were analysed, providing, for the first time, the retinoid composition of both buffalo's and ewe's milk. According to the literature, retinyl palmitate has been found to be the most abundant vitamin A vitamer, but retinyl oleate is the prevalent form in the caprine milk. PMID:27283655

  8. Simultaneous determination of drugs of abuse and their main metabolites using pressurized liquid extraction and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Arbeláez, Paula; Borrull, Francesc; Maria Marcé, Rosa; Pocurull, Eva

    2014-07-01

    An analytical method based on pressurized liquid extraction (PLE) and liquid chromatography-(electrospray)-tandem mass spectrometry was developed for the simultaneous determination of nicotine, four drugs of abuse (opiates and alkaloids) and four of their main metabolites in sewage sludge. The optimum PLE conditions were: cell volume 11 mL, dichloromethane as extraction solvent, 5 min preheating time, 100 °C temperature, 1500 psi pressure, 60% flush volume, 1 cycle, 15 min static extraction time, 120 s purge time and sample weight 1g. Absolute recoveries for all compounds were between 25% and 65%. Data acquisition was done by selective reaction monitoring and the two most abundant product ions were used for confirmation. Limits of detection were lower than 10 μg/kg dry weight (d.w.) and limits of quantification were between 2.5 and 25 μg/kg (d.w.). The highest concentrations found in sludge samples from two sewage treatment plants were for nicotine and cocaine in the range of 23-173 μg/kg (d.w.) and 9-232 μg/kg (d.w.) respectively. PMID:24840416

  9. Novel and sensitive reversed-phase high-pressure liquid chromatography method with electrochemical detection for the simultaneous and fast determination of eight biogenic amines and metabolites in human brain tissue.

    Science.gov (United States)

    Van Dam, Debby; Vermeiren, Yannick; Aerts, Tony; De Deyn, Peter Paul

    2014-08-01

    A fast and simple RP-HPLC method with electrochemical detection (ECD) and ion pair chromatography was developed, optimized and validated in order to simultaneously determine eight different biogenic amines and metabolites in post-mortem human brain tissue in a single-run analytical approach. The compounds of interest are the indolamine serotonin (5-hydroxytryptamine, 5-HT), the catecholamines dopamine (DA) and (nor)epinephrine ((N)E), as well as their respective metabolites, i.e. 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), 5-hydroxy-3-indoleacetic acid (5-HIAA) and 3-methoxy-4-hydroxyphenylglycol (MHPG). A two-level fractional factorial experimental design was applied to study the effect of five experimental factors (i.e. the ion-pair counter concentration, the level of organic modifier, the pH of the mobile phase, the temperature of the column, and the voltage setting of the detector) on the chromatographic behaviour. The cross effect between the five quantitative factors and the capacity and separation factors of the analytes were then analysed using a Standard Least Squares model. The optimized method was fully validated according to the requirements of SFSTP (Société Française des Sciences et Techniques Pharmaceutiques). Our human brain tissue sample preparation procedure is straightforward and relatively short, which allows samples to be loaded onto the HPLC system within approximately 4h. Additionally, a high sample throughput was achieved after optimization due to a total runtime of maximally 40min per sample. The conditions and settings of the HPLC system were found to be accurate with high intra and inter-assay repeatability, recovery and accuracy rates. The robust analytical method results in very low detection limits and good separation for all of the eight biogenic amines and metabolites in this complex mixture of biological analytes. PMID:24857034

  10. Comprehensive sample analysis using high performance liquid chromatography with multi-detection

    International Nuclear Information System (INIS)

    Graphical abstract: -- Highlights: •Detection selectivity was assessed with 6 detection modes. •Natural samples show great diversity in detection selectivity. •Complex samples require evaluation using a multifaceted approach to detection. •23/30 known compounds (detected by MS) detected by chemiluminescence, DPPH and UV. -- Abstract: Herein we assess the separation space offered by a liquid chromatography system with an optimised uni-dimensional separation for the determination of the key chemical entities in the highly complex matrix of a tobacco leaf extract. Multiple modes of detection, including UV–visible absorbance, chemiluminescence (acidic potassium permanganate, manganese(IV), and tris(2,2′-bipyridine)ruthenium(III)), mass spectrometry and DPPH radical scavenging were used in an attempt to systematically reduce the data complexity of the sample whilst obtaining a greater degree of molecule-specific information. A large amount of chemical data was obtained, but several limitations in the ability to assign detector responses to particular compounds, even with the aid of complementary detection systems, were observed. Thirty-three compounds were detected via MS on the tobacco extract and 12 out of 32 compounds gave a peak height ratio (PHR) greater than 0.33 on one or more detectors. This paper serves as a case study of these limitations, illustrating why multidimensional chromatography is an important consideration when developing a comprehensive chemical detection system

  11. Comprehensive sample analysis using high performance liquid chromatography with multi-detection

    Energy Technology Data Exchange (ETDEWEB)

    Pravadali, Sercan [Australian Centre for Research on Separation Sciences (ACROSS), School of Science and Health, University of Western Sydney (Parramatta), NSW 1797 (Australia); Bassanese, Danielle N.; Conlan, Xavier A.; Francis, Paul S.; Smith, Zoe M.; Terry, Jessica M. [Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences, Deakin University, Victoria 3216 (Australia); Shalliker, R. Andrew, E-mail: R.Shalliker@uws.edu.au [Australian Centre for Research on Separation Sciences (ACROSS), School of Science and Health, University of Western Sydney (Parramatta), NSW 1797 (Australia)

    2013-11-25

    Graphical abstract: -- Highlights: •Detection selectivity was assessed with 6 detection modes. •Natural samples show great diversity in detection selectivity. •Complex samples require evaluation using a multifaceted approach to detection. •23/30 known compounds (detected by MS) detected by chemiluminescence, DPPH and UV. -- Abstract: Herein we assess the separation space offered by a liquid chromatography system with an optimised uni-dimensional separation for the determination of the key chemical entities in the highly complex matrix of a tobacco leaf extract. Multiple modes of detection, including UV–visible absorbance, chemiluminescence (acidic potassium permanganate, manganese(IV), and tris(2,2′-bipyridine)ruthenium(III)), mass spectrometry and DPPH radical scavenging were used in an attempt to systematically reduce the data complexity of the sample whilst obtaining a greater degree of molecule-specific information. A large amount of chemical data was obtained, but several limitations in the ability to assign detector responses to particular compounds, even with the aid of complementary detection systems, were observed. Thirty-three compounds were detected via MS on the tobacco extract and 12 out of 32 compounds gave a peak height ratio (PHR) greater than 0.33 on one or more detectors. This paper serves as a case study of these limitations, illustrating why multidimensional chromatography is an important consideration when developing a comprehensive chemical detection system.

  12. Determination of Acrylamide Metabolite ,Mercapturic Aicd by High Performance Liquid Chromatography

    Institute of Scientific and Technical Information of China (English)

    WUYi-Qun; YUAi-Ru; 等

    1993-01-01

    A HPLC Assay was developed to indentify and measure the metabolite of acrylamide,mercapturic acid,N-Acetyl-s-(propionamide)-cyteine(APC)in urine O-phthalaldehyde (OPA)was utilized as a precolumm derivatizing agent in the assay.This derivative was isolated with a good selectivity by high performance liquid chromatography(HPLC)employing reversed phase ODS columns.The quantiation of the mercapturic acid derivative was reproducible and with a detection limit of 1 pmol.The average coefficient of variation for the runs carried out on the same day was approximately 4.6% at the range of 80-160μmol·l-1 of APC,and the mean analytical recovery from urine samples was 94%.The metabolite of urine of workers exposed to acrylamide was identified as N-acetyl-s-(propionamide)-cysteine by HPLC chromatography and fluorescence scan and HPLC-Mass spectra.All results were identical with the authentic synthesized compound.

  13. Determination of clomazone residues in soybean and soil by high performance liquid chromatography with DAD detection.

    Science.gov (United States)

    Hu, Jiye; Cao, Di; Deng, Zhubo

    2011-04-01

    A simple analysis method to detect clomazone residues in soybean and soil was developed using solid phase extraction coupled with high performance liquid chromatography with diode-array detection. The pesticide residues present in soybean and soil matrices were extracted with methanol-water and extracts purified with Florisil cartridges. The analytes from soybean and soil matrix were eluted with petroleum ether-acetic ether (10 mL, 95:5, v/v) and petroleum ether-acetic ether (2 mL, 95:5, v/v), respectively. The overall recovery of fortified soybean and soil at the levels of 0.01, 0.1 and 0.5 mg/kg ranged from 89.75% to 106.6%, and the coefficients of variation (CV) ranged from 1.68% to 4.93% (n = 3). The limit of quantification (LOQ) is 0.01 mg/kg. This method has been applied to the analysis of clomazone in real samples of soybean and soil. The dissipation of residue over the time in soil coincided with C = 1.189e(-0.0926t ) and the half-lives (T(1/2)) was 7.48 days. The final residue in soybean was lower than 0.01 mg/kg at harvest time. Direct confirmation of the analyte in real samples was achieved by gas chromatography-mass spectrometry.

  14. Comprehensive sample analysis using high performance liquid chromatography with multi-detection.

    Science.gov (United States)

    Pravadali, Sercan; Bassanese, Danielle N; Conlan, Xavier A; Francis, Paul S; Smith, Zoe M; Terry, Jessica M; Shalliker, R Andrew

    2013-11-25

    Herein we assess the separation space offered by a liquid chromatography system with an optimised uni-dimensional separation for the determination of the key chemical entities in the highly complex matrix of a tobacco leaf extract. Multiple modes of detection, including UV-visible absorbance, chemiluminescence (acidic potassium permanganate, manganese(IV), and tris(2,2'-bipyridine)ruthenium(III)), mass spectrometry and DPPH radical scavenging were used in an attempt to systematically reduce the data complexity of the sample whilst obtaining a greater degree of molecule-specific information. A large amount of chemical data was obtained, but several limitations in the ability to assign detector responses to particular compounds, even with the aid of complementary detection systems, were observed. Thirty-three compounds were detected via MS on the tobacco extract and 12 out of 32 compounds gave a peak height ratio (PHR) greater than 0.33 on one or more detectors. This paper serves as a case study of these limitations, illustrating why multidimensional chromatography is an important consideration when developing a comprehensive chemical detection system. PMID:24216214

  15. [Simultaneous determination of diflubenzuron and triflumuron residues in greasy wool using high performance liquid chromatography].

    Science.gov (United States)

    Wang, Heng; Zhao, Jie; Chen, Zhiwei; He, Pingang; Fang, Yuzhi

    2008-11-01

    A new method has been developed for the simultaneous determination of diflubenzuron and triflumuron residues in greasy wool by reversed-phase high performance liquid chromatography (HPLC). The pesticides were extracted by hexane-ether from greasy wool and cleaned up with gel permeation chromatography (GPC) and solid phase extraction (SPE). The pesticides were analyzed by HPLC-diode array detector (DAD) and quantified by external standard method. The linear ranges of diflubenzuron and triflumuron were 0.41 -41 mg/L and 0.38 - 38 mg/L, and the correlation coefficients were 0.999 6 and 0.999 9, respectively. The limits of detection were 0.22 mg/kg for diflubenzuron and 0.18 mg/kg for triflumuron; the limits of quantification were 0.73 mg/kg for diflubenzuron and 0.60 mg/kg for triflumuron. The average recoveries of pesticides spiked levels from 0.76 to 10.25 mg/kg in greasy wool samples were in the range of 86.3% - 96.7%, and the relative standard deviations were 4.2% - 8.7%. The method developed shows little interferences, good recovery and repeatability. It is suitable for the simultaneous determination of diflubenzuron and triflumuron in greasy wool samples. PMID:19253555

  16. High Performance Liquid Chromatography of Some Analgesic Compounds: An Instrumental Analysis Experiment.

    Science.gov (United States)

    Haddad, Paul; And Others

    1983-01-01

    Background information, procedures, and results are provided for an experiment demonstrating techniques of solvent selection, gradient elution, pH control, and ion-pairing in the analysis of an analgesic mixture using reversed-phase liquid chromatography on an octadecylsilane column. Although developed using sophisticated/expensive equipment, less…

  17. Parallel segmented outlet flow high performance liquid chromatography with multiplexed detection

    Energy Technology Data Exchange (ETDEWEB)

    Camenzuli, Michelle [Australian Centre for Research on Separation Science (ACROSS), School of Science and Health, University of Western Sydney (Parramatta), Sydney, NSW (Australia); Terry, Jessica M. [Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3216 (Australia); Shalliker, R. Andrew, E-mail: r.shalliker@uws.edu.au [Australian Centre for Research on Separation Science (ACROSS), School of Science and Health, University of Western Sydney (Parramatta), Sydney, NSW (Australia); Conlan, Xavier A.; Barnett, Neil W. [Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3216 (Australia); Francis, Paul S., E-mail: paul.francis@deakin.edu.au [Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3216 (Australia)

    2013-11-25

    Graphical abstract: -- Highlights: •Multiplexed detection for liquid chromatography. •‘Parallel segmented outlet flow’ distributes inner and outer portions of the analyte zone. •Three detectors were used simultaneously for the determination of opiate alkaloids. -- Abstract: We describe a new approach to multiplex detection for HPLC, exploiting parallel segmented outlet flow – a new column technology that provides pressure-regulated control of eluate flow through multiple outlet channels, which minimises the additional dead volume associated with conventional post-column flow splitting. Using three detectors: one UV-absorbance and two chemiluminescence systems (tris(2,2′-bipyridine)ruthenium(III) and permanganate), we examine the relative responses for six opium poppy (Papaver somniferum) alkaloids under conventional and multiplexed conditions, where approximately 30% of the eluate was distributed to each detector and the remaining solution directed to a collection vessel. The parallel segmented outlet flow mode of operation offers advantages in terms of solvent consumption, waste generation, total analysis time and solute band volume when applying multiple detectors to HPLC, but the manner in which each detection system is influenced by changes in solute concentration and solution flow rates must be carefully considered.

  18. Simple high-performance liquid chromatography method for formaldehyde determination in human tissue through derivatization with 2,4-dinitrophenylhydrazine.

    Science.gov (United States)

    Yilmaz, Bilal; Asci, Ali; Kucukoglu, Kaan; Albayrak, Mevlut

    2016-08-01

    A simple high-performance liquid chromatography method has been developed for the determination of formaldehyde in human tissue. FA Formaldehyde was derivatized with 2,4-dinitrophenylhydrazine. It was extracted from human tissue with ethyl acetate by liquid-liquid extraction and analyzed by high-performance liquid chromatography. The calibration curve was linear in the concentration range of 5.0-200 μg/mL. Intra- and interday precision values for formaldehyde in tissue were formaldehyde from human tissue were between 88 and 98%. The limits of detection and quantification of formaldehyde were 1.5 and 5.0 μg/mL, respectively. Also, this assay was applied to liver samples taken from a biopsy material. PMID:27291155

  19. High Performance Liquid Chromatography Tandem Mass Spectrometry Measurement of Bimatoprost, Latanoprost and Travoprost in Eyelash Enhancing Cosmetic Serums

    Directory of Open Access Journals (Sweden)

    Emilia Marchei

    2016-02-01

    Full Text Available Most common prostaglandin analogs, bimatoprost, latanoprost and travoprost, are licensed for the reduction of elevated intraocular pressure in patients with open angle glaucoma and ocular hypertension, but their non approved use as eyelash enhancers is becoming popular, especially in patients with eyelashes hypotrichosis. A fast and sensitive high performance liquid chromatography tandem mass spectrometry method was developed for the measurement of bimatoprost, latanoprost and travoprost in cosmetic serums freely web-sold to increase eyelash length, thickness and darkness. The analytes and the internal standard (reserpine were separated by reversed phase chromatography with 5 mM ammonium acetate with 0.02% formic acid (mobile phase A and 5 mM ammonium acetate in acetonitrile/water (95/5; v/v with 0.02% formic acid (mobile phase B by gradient elution and detected with tandem mass spectrometry operated in multiple reaction monitoring mode. Linearity between 1 and 500 μg/g shows good correlation coefficients (r2 = 0.99 for all substances. Analytical recovery of analytes under investigation were always higher than 90% and intra-assay and inter-assay precision and accuracy always better than 11%. This method was successfully applied to analyze cosmetic serums freely sold on the Internet websites.

  20. Evaluation of Ternary Mobile Phases for the Analysis of Carbonyl Compound Derivatives Using High-Performance Liquid Chromatography

    OpenAIRE

    Duy Xuan Ho; Ki-Hyun Kim

    2011-01-01

    In this study, the feasibility of ternary mobile phases was examined in a high-performance liquid chromatography (HPLC)-based analysis of carbonyl compounds (CCs). To test the performance of different ternary phases, the liquid phase standards containing a 15 aldehyde/ketone-DNPH(o) mix were analyzed through a series of five-point calibration experiments. For this comparison, three types of ternary mobile phases were prepared initially by mixing water (W) with two of the following three organ...

  1. [Measurement of 11 benzophenone ultraviolet-filters in cosmetics by high performance liquid chromatography].

    Science.gov (United States)

    Qu, Baocheng; Bian, Haitao; Mao, Xiqin; Li, Jin

    2015-12-01

    A sample preparation and analytical method with liquid-liquid extraction (LLE) and high performance liquid chromatography (HPLC) was developed to detect 11 benzophenone ultraviolet-filters in cosmetics. The target compounds were extracted by the mixed solutions of tetrahydrofuran (TH)/methanol/water or dichloromethane/water at proper ratios. The extracts were centrifuged and filtered to remove matrix compounds, and then analyzed by HPLC. The separation of analytes was carried out on a Diamonsil-C18 column (150 mm x 4.6 mm, 5 μm) with 0.1% (v/v) formic acid aqueous solution (containing 10 mmol/L ammonium acetate) as mobile phase A and methanol containing 0.1% (v/v) formic acid as mobile phase B. The spiked recoveries of the method (n = 7) were 93.4%-103.8% with the relative standard deviations of 0.1%-4.2%. The limits of detection (LODs) were in the range of 4.0-30 μg/g and the limits of quantitation (LOQs) ranged from 15 to 100 μg/g. The method was applied to the determination of 42 cosmetic samples randomly purchased from the supermarket in Dalian. Five benzophenone series were always detected, in which the content of benzophenone-3 in sunscreen cream and the content of benzophenone-2 in perfume were very high and reached 2 785 μg/g and 2 106 μg/g, respectively. The results showed that the developed method is efficient, reliable and sensitive, which can be applied to the determination of benzophenones in cosmetics.

  2. Elucidation and identification of amino acid containing membrane lipids using liquid chromatography/high-resolution mass spectrometry

    NARCIS (Netherlands)

    Moore, E.K.; Hopmans, E.C.; Rijpstra, W.I.C.; Villanueva, L.; Sinninghe Damste, J.S.

    2016-01-01

    RATIONALE: Intact polar lipids (IPLs) are the building blocks of cell membranes, and amino acid containing IPLs havebeen observed to be involved in response to changing environmental conditions in various species of bacteri a. High-performance liquid chromatography/mass spectrometry (HPLC/MS) has be

  3. Simultaneous Determination of Caffeine and Vitamin B6 in Energy Drinks by High-Performance Liquid Chromatography (HPLC)

    Science.gov (United States)

    Leacock, Rachel E.; Stankus, John J.; Davis, Julian M.

    2011-01-01

    A high-performance liquid chromatography experiment to determine the concentration of caffeine and vitamin B6 in sports energy drinks has been developed. This laboratory activity, which is appropriate for an upper-level instrumental analysis course, illustrates the standard addition method and simultaneous determination of two species. (Contains 1…

  4. Constructing a LabVIEW-Controlled High-Performance Liquid Chromatography (HPLC) System: An Undergraduate Instrumental Methods Exercise

    Science.gov (United States)

    Smith, Eugene T.; Hill, Marc

    2011-01-01

    In this laboratory exercise, students develop a LabVIEW-controlled high-performance liquid chromatography system utilizing a data acquisition device, two pumps, a detector, and fraction collector. The programming experience involves a variety of methods for interface communication, including serial control, analog-to-digital conversion, and…

  5. The Determination of Polyethylene Glycol in Untreated Urine Samples by High Performance Liquid Chromatography for Intestinal Permeability Studies

    DEFF Research Database (Denmark)

    Larsen, Elfinn; Pedersen, Walther Batsberg; Philipsen, E.

    1985-01-01

    Polyethylene glycol in urine samples has been investigated by high performance liquid chromatography. The molecular weights ranged from 634 to 1338. The urine samples were applied to the chromatographic system without any pre-treatment. For samples with a concentration of 0.2% polyethylene glycol...

  6. Simultaneous determination of estrogens and progestogens in honey using high performance liquid chromatography-tandem mass spectrometry

    Science.gov (United States)

    This work describes the development and validation of a method for the simultaneous determination of 13 estrogens and progestogens in honey by high performance liquid chromatography-tandem mass spectrometry. The target compounds were preconcentrated by solid phase extraction. Pretreatment variables ...

  7. Analysis of native human plasma proteins and haemoglobin for the presence of bityrosine by high-performance liquid chromatography

    DEFF Research Database (Denmark)

    Daneshvar, B; Frandsen, H; Dragsted, L O;

    1997-01-01

    fluorescent substance, bityrosine. High-performance liquid chromatography (HPLC) analysis of acid hydrolyzed serum albumin after oxidation with peroxidase/H2O2 or with Cu++/H2O2 showed that bityrosine had been formed whereas oxidation of this protein with Fe(III)/ascorbate did not result in the formation...

  8. Determination of methyldibromoglutaronitrile in cosmetic products by high-performance liquid chromatography with electrochemical detection. Method validation

    DEFF Research Database (Denmark)

    Rastogi, Suresh Chandra; Zachariae, Claus; Johansen, Jeanne D;

    2004-01-01

    An increased frequency of contact allergy to methyldibromoglutaronitrile (MDBGN), a commonly used preservative in cosmetics and other consumer products, has been reported in recent years. A high-performance liquid chromatography (HPLC) method for the determination of MDBGN in cosmetic products ha...

  9. Screening antiallergic components from Carthamus tinctorius using rat basophilic leukemia 2H3 cell membrane chromatography combined with high-performance liquid chromatography and tandem mass spectrometry.

    Science.gov (United States)

    Han, Shengli; Huang, Jing; Cui, Ronghua; Zhang, Tao

    2015-02-01

    Carthamus tinctorius, used in traditional Chinese medicine, has many pharmacological effects, such as anticoagulant effects, antioxidant effects, antiaging effects, regulation of gene expression, and antitumor effects. However, there is no report on the antiallergic effects of the components in C. tinctorius. In the present study, we investigated the antiallergic components of C. tinctorius and its mechanism of action. A rat basophilic leukemia 2H3/cell membrane chromatography coupled online with high-performance liquid chromatography and tandem mass spectrometry method was developed to screen antiallergic components from C. tinctorius. The screening results showed that Hydroxysafflor yellow A, from C. tinctorius, was the targeted component that retained on the rat basophilic leukemia 2H3/cell membrane chromatography column. We measured the amount of β-hexosaminidase and histamine released in mast cells and the key markers of degranulation. The release assays showed that Hydroxysafflor yellow A could attenuate the immunoglobulin E induced release of allergic cytokines without affecting cell viability from 1.0 to 50.0 μM. In conclusion, the established rat basophilic leukemia 2H3 cell membrane chromatography coupled with online high-performance liquid chromatography and tandem mass spectrometry method successfully screened and identified Hydroxysafflor yellow A from C. tinctorius as a potential antiallergic component. Pharmacological analysis elucidated that Hydroxysafflor yellow A is an effective natural component for inhibiting immunoglobulin E-antigen-mediated degranulation.

  10. Determination of Niacinamide in Lotions and Creams Using Liquid-Liquid Extraction and High-Performance Liquid Chromatography

    Science.gov (United States)

    Usher, Karyn M.; Simmons, Carolyn R.; Keating, Daniel W.; Rossi, Henry F., III

    2015-01-01

    Chemical separations are an important part of an undergraduate chemistry curriculum. Sophomore students often get experience with liquid-liquid extraction in organic chemistry classes, but liquid-liquid extraction is not as often introduced as a quantitative sample preparation method in honors general chemistry or quantitative analysis classes.…

  11. Sampling frequency, response times and embedded signal filtration in fast, high efficiency liquid chromatography: A tutorial.

    Science.gov (United States)

    Wahab, M Farooq; Dasgupta, Purnendu K; Kadjo, Akinde F; Armstrong, Daniel W

    2016-02-11

    With increasingly efficient columns, eluite peaks are increasingly narrower. To take full advantage of this, choice of the detector response time and the data acquisition rate a.k.a. detector sampling frequency, have become increasingly important. In this work, we revisit the concept of data sampling from the theorem variously attributed to Whittaker, Nyquist, Kotelnikov, and Shannon. Focusing on time scales relevant to the current practice of high performance liquid chromatography (HPLC) and optical absorbance detection (the most commonly used method), even for very narrow simulated peaks Fourier transformation shows that theoretical minimum sampling frequency is still relatively low (digital filters. We show that the common wisdom of sampling 20 points per peak can be inadequate for high efficiency columns and that the sampling frequency and response choices do affect the peak shape. If the sampling frequency is too low or response time is too large, the observed peak shapes will not remain as narrow as they really are - this is especially true for high efficiency and high speed separations. It is shown that both sampling frequency and digital filtering affect the retention time, noise amplitude, peak shape and width in a complex fashion. We show how a square-wave driven light emitting diode source can reveal the nature of the embedded filter. We discuss time uncertainties related to the choice of sampling frequency. Finally, we suggest steps to obtain optimum results from a given system. PMID:26803000

  12. Quality Evaluation of Potentilla fruticosa L. by High Performance Liquid Chromatography Fingerprinting Associated with Chemometric Methods

    Science.gov (United States)

    Liu, Wei; Wang, Dongmei; Liu, Jianjun; Li, Dengwu; Yin, Dongxue

    2016-01-01

    The present study was performed to assess the quality of Potentilla fruticosa L. sampled from distinct regions of China using high performance liquid chromatography (HPLC) fingerprinting coupled with a suite of chemometric methods. For this quantitative analysis, the main active phytochemical compositions and the antioxidant activity in P. fruticosa were also investigated. Considering the high percentages and antioxidant activities of phytochemicals, P. fruticosa samples from Kangding, Sichuan were selected as the most valuable raw materials. Similarity analysis (SA) of HPLC fingerprints, hierarchical cluster analysis (HCA), principle component analysis (PCA), and discriminant analysis (DA) were further employed to provide accurate classification and quality estimates of P. fruticosa. Two principal components (PCs) were collected by PCA. PC1 separated samples from Kangding, Sichuan, capturing 57.64% of the variance, whereas PC2 contributed to further separation, capturing 18.97% of the variance. Two kinds of discriminant functions with a 100% discrimination ratio were constructed. The results strongly supported the conclusion that the eight samples from different regions were clustered into three major groups, corresponding with their morphological classification, for which HPLC analysis confirmed the considerable variation in phytochemical compositions and that P. fruticosa samples from Kangding, Sichuan were of high quality. The results of SA, HCA, PCA, and DA were in agreement and performed well for the quality assessment of P. fruticosa. Consequently, HPLC fingerprinting coupled with chemometric techniques provides a highly flexible and reliable method for the quality evaluation of traditional Chinese medicines. PMID:26890416

  13. Sampling frequency, response times and embedded signal filtration in fast, high efficiency liquid chromatography: A tutorial.

    Science.gov (United States)

    Wahab, M Farooq; Dasgupta, Purnendu K; Kadjo, Akinde F; Armstrong, Daniel W

    2016-02-11

    With increasingly efficient columns, eluite peaks are increasingly narrower. To take full advantage of this, choice of the detector response time and the data acquisition rate a.k.a. detector sampling frequency, have become increasingly important. In this work, we revisit the concept of data sampling from the theorem variously attributed to Whittaker, Nyquist, Kotelnikov, and Shannon. Focusing on time scales relevant to the current practice of high performance liquid chromatography (HPLC) and optical absorbance detection (the most commonly used method), even for very narrow simulated peaks Fourier transformation shows that theoretical minimum sampling frequency is still relatively low (digital filters. We show that the common wisdom of sampling 20 points per peak can be inadequate for high efficiency columns and that the sampling frequency and response choices do affect the peak shape. If the sampling frequency is too low or response time is too large, the observed peak shapes will not remain as narrow as they really are - this is especially true for high efficiency and high speed separations. It is shown that both sampling frequency and digital filtering affect the retention time, noise amplitude, peak shape and width in a complex fashion. We show how a square-wave driven light emitting diode source can reveal the nature of the embedded filter. We discuss time uncertainties related to the choice of sampling frequency. Finally, we suggest steps to obtain optimum results from a given system.

  14. On-line high speed lipid extraction for nanoflow liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Lee, Ju Yong; Yang, Joon Seon; Park, Se Mi; Byeon, Seul Kee; Moon, Myeong Hee

    2016-09-16

    An on-line lipid extraction method is introduced by utilizing a short capillary extraction column using HILIC and C4 particles prior to nanoflow liquid chromatography-tandem mass spectrometry (nLC-MS/MS). The on-line extraction using a urine sample spiked with PL standards showed similar or slightly higher recovery values (86%-96%) of phospholipids (PLs) compared to those obtained by the conventional off-line extraction based on the Folch method with or without using the air-exposed drying process. In this study, we demonstrated that PL oxidation can occur during the air-exposed drying process of lipid extracts in standard liquid-liquid extraction procedures, which was confirmed by the oxidized PL (OxPL) molecules that were generated from an off-line extraction using a few PL standards. Quantitative comparison of these OxPL species between on- and off-line extraction followed by nLC-MS/MS with multiple reaction monitoring (MRM) analysis showed a significant decrease (2-10 fold) in unwanted OxPL species when on-line extraction was employed. While the number of identified PLs from a urine sample was somewhat lower than those by off-line extraction, the number of OxPLs was significantly reduced (from 70 to 22) with on-line extraction. The new method offers high speed (∼5min) automated extraction of PLs with nLC-MS/MS analysis and presents the possibility of handling a biological sample with a very limited amount of lipids. PMID:27530420

  15. Relationship between High-Performance Liquid Chromatography Fingerprints and Uric Acid-Lowering Activities of Cichorium intybus L.

    Science.gov (United States)

    Zhu, Chun-Sheng; Zhang, Bing; Lin, Zhi-Jian; Wang, Xue-Jie; Zhou, Yue; Sun, Xiao-Xia; Xiao, Ming-Liang

    2015-01-01

    This study aimed to explore the spectrum-effect relationships between high-performance liquid chromatography fingerprints and the uric acid-lowering activities of chicory. Chemical fingerprints of chicory samples from ten different sources were determined by high-performance liquid chromatography, and then investigated by similarity analysis and hierarchical clustering analysis. Pharmacodynamics experiments were conducted in animals to obtain the uric acid-lowering activity information of each chicory sample. The spectrum-effect relationships between chemical fingerprints and the uric acid-lowering activities of chicory were established by canonical correlation analysis. The structures of potential effective peaks were identified by liquid chromatography with tandem mass spectrometry. The results showed that a close correlation existed between the spectrum and effect of chicory. Aesculin, chlorogenic acid, chicoric acid, isochlorogenic acid A/B/C and 13,14-seco-stigma5(6),14(15)-diene-3α-ol might be the main effective constituents. This work provides a general model of the combination of high-performance liquid chromatography and uric acid-lowering activities to study the spectrum-effect relationships of chicory, which can be used to discover the principle components responsible for the bioactivity. PMID:26007193

  16. Quantitative Analysis of Sphingomyelin by High-Performance Liquid Chromatography after Enzymatic Hydrolysis

    Directory of Open Access Journals (Sweden)

    Seunghyun Lee

    2012-01-01

    Full Text Available Sphingomyelin is the most abundant sphingolipid in mammalian cells and is mostly present in the plasma membrane. A new analytical method using high-performance liquid chromatography (HPLC was developed to quantify sphingomyelin in mouse plasma and tissues, 3T3-L1 cells, rat aortic smooth muscle cells, and HT-29 cells. Sphingomyelin and dihydrosphingomyelin, an internal standard, were separated by high-performance thin-layer chromatography and simultaneously hydrolyzed with sphingolipid ceramide N-deacylase and sphingomyelinase to release sphingosine and dihydrosphingosine, respectively. Sphingomyelin content was measured by HPLC following o-phthalaldehyde derivatization. Sphingomyelin concentrations in 3T3-L1 cells, rat aortic smooth muscle cells, and HT-29 cells were 60.10±0.24, 62.69±0.08, and 58.38±0.37 pmol/μg protein, respectively, whereas those in brain, kidney, and liver of ICR mice were 55.60±0.43, 43.75±0.21, and 22.26±0.14 pmol/μg protein. The sphingomyelin concentration in mouse plasma was 407.40±0.31 μM. The limits of detection and quantification for sphingomyelin were 5 and 20 pmol, respectively, in the HPLC analysis with fluorescence detection. This sensitivity was sufficient for analyzing sphingomyelin in biological samples. In conclusion, this analytical method is a sensitive and specific technique for quantifying sphingomyelin and was successfully applied to diverse biological samples with excellent reproducibility.

  17. Enantiomeric separation of organophosphorus pesticides by high-performance liquid chromatography, gas chromatography and capillary electrophoresis and their applications to environmental fate and toxicity assays.

    Science.gov (United States)

    Li, Ling; Zhou, Shanshan; Jin, Lixia; Zhang, Cheng; Liu, Weiping

    2010-05-15

    In recent years, the continuous evolution of the field of stereochemistry has produced a heightened awareness of the applications of pure enantiomers of agrochemicals. This review describes reports of the enantiomeric separation of commercial organophosphorus pesticides (OPs) and the applications of these methods to research on the enantioselectivity of the toxicity and environmental fate of these compounds. Chiral OPs can be analysed by high-performance liquid chromatography (HPLC), gas chromatography (GC), and capillary electrophoresis (CE). These different separation techniques for OP enantiomers are briefly discussed, and their applications are presented.

  18. Monitoring gradient profile on-line in micro- and nano-high performance liquid chromatography using conductivity detection.

    Science.gov (United States)

    Zhang, Min; Chen, Apeng; Lu, Joann J; Cao, Chengxi; Liu, Shaorong

    2016-08-19

    In micro- or nano-flow high performance liquid chromatography (HPLC), flow-splitters and gradient elutions are commonly used for reverse phase HPLC separations. When a flow splitter was used at a high split-ratio (e.g., 1000:1 or higher), the actual gradient may deviate away from the programmed gradient. Sometimes, mobile phase concentrations can deviate by as much as 5%. In this work, we noticed that the conductivity (σ) of a gradient decreased with the increasing organic-solvent fraction (φ). Based on the relationship between σ and φ, a method was developed for monitoring gradient profile on-line to record any deviations in these HPLC systems. The conductivity could be measured by a traditional conductivity detector or a capacitively coupled contactless conductivity detector (C(4)D). The method was applied for assessing the performance of an electroosmotic pump (EOP) based nano-HPLC. We also observed that σ value of the gradient changed with system pressure; a=0.0175ΔP (R(2)=0.964), where a is the percentage of the conductivity increase and ΔP is the system pressure in bar. This effect was also investigated.

  19. A field survey of metal binding to metallothionein and other cytosolic ligands in liver of eels using an on-line isotope dilution method in combination with size exclusion (SE) high pressure liquid chromatography (HPLC) coupled to Inductively Coupled Plasma time-of-flight Mass Spectrometry (ICP-TOFMS).

    Science.gov (United States)

    Van Campenhout, Karen; Goenaga Infante, Heidi; Goemans, Geert; Belpaire, Claude; Adams, Freddy; Blust, Ronny; Bervoets, Lieven

    2008-05-15

    The effect of metal exposure on the accumulation and cytosolic speciation of metals in livers of wild populations of European eel with special emphasis on metallothioneins (MT) was studied. Four sampling sites in Flanders showing different degrees of heavy metal contamination were selected for this purpose. An on-line isotope dilution method in combination with size exclusion (SE) high pressure liquid chromatography (HPLC) coupled to Inductively Coupled Plasma time-of-flight Mass Spectrometry (ICP-TOFMS) was used to study the cytosolic speciation of the metals. The distribution of the metals Cd, Cu, Ni, Pb and Zn among cytosolic fractions displayed strong differences. The cytosolic concentration of Cd, Ni and Pb increased proportionally with the total liver levels. However, the cytosolic concentrations of Cu and Zn only increased above a certain liver tissue threshold level. Cd, Cu and Zn, but not Pb and Ni, were largely associated with the MT pool in correspondence with the environmental exposure and liver tissue concentrations. Most of the Pb and Ni and a considerable fraction of Cu and Zn, but not Cd, were associated to High Molecular Weight (HMW) fractions. The relative importance of the Cu and Zn in the HMW fraction decreased with increasing contamination levels while the MT pool became progressively more important. The close relationship between the cytosolic metal load and the total MT levels or the metals bound on the MT pool indicates that the metals, rather than other stress factors, are the major factor determining MT induction.

  20. Determination of major carotenoids in a few Indian leafy vegetables by high-performance liquid chromatography.

    Science.gov (United States)

    Lakshminarayana, Rangaswamy; Raju, Marisiddaiah; Krishnakantha, Thirumalai Parthasarathy; Baskaran, Vallikannan

    2005-04-20

    Leafy vegetables [Basella rubra L., Peucedanum sowa Roxb., Moringa oleifera Lam., Trigonella foenum-graecum L., Spinacia oleracea L., Sesbania grandiflora (L.) Poir., and Raphanus sativus L.] that are commonly used by the rural population in India were evaluated in terms of their main carotenoid pattern. The extracted carotenoids were purified by open column chromatography (OCC) on a neutral alumina column to verify their identity by their characteristic UV-visible absorption spectra. Reverse-phase high-performance liquid chromatography (HPLC) on a C18 column with UV-visible photodiode array detection under isocratic conditions was used for quantification of isolated carotenoids. Acetonitrile/methanol/dichloromethane (60:20:20 v/v/v) containing 0.1% ammonium acetate was used as a mobile phase. The major carotenoids identified by both methods were lutein, beta-carotene, violaxanthin, neoxanthin, and zeaxanthin. Among the carotenoids identified, lutein and beta-carotene levels were found to be higher in these leafy vegetables. Results show that P. sowa and S. oleracea are rich sources of lutein (77-92 mg/100 g of dry wt) and beta-carotene (36-44 mg/100 g of dry wt) compared with other leafy vegetables. The purity of carotenoids eluted by OCC was clarified by HPLC, and they were found to be 92% +/- 3% for neoxanthin, 94% +/- 2% for violaxanthin, 97% +/-2% for lutein and zeaxanthin, and 90% +/- 3% for beta-carotene. It could be recommended to use P. sowa and S. oleracea as rich sources of lutein and beta-carotene for health benefits. The OCC method proposed is relatively simple and provides purified carotenoids for feeding trials. PMID:15826027

  1. Protocols for finding the most orthogonal dimensions for two-dimensional high performance liquid chromatography.

    Science.gov (United States)

    Bassanese, Danielle N; Holland, Brendan J; Conlan, Xavier A; Francis, Paul S; Barnett, Neil W; Stevenson, Paul G

    2015-03-01

    The selection of two high performance liquid chromatography (HPLC) columns with vastly different retention mechanisms is vital for performing effective two-dimensional (2D-) HPLC. This paper reports on a systematic method to select a pair of HPLC columns that provide the most different separations for a given sample. This was completed with the aid of a HPLC simulator that predicted retention profiles on the basis of real experimental data, which is difficult when the contents of sample matrices are largely-or completely-unknown. Peaks from the same compounds must first be matched between chromatograms to compare the retention profiles and optimised 2D-HPLC column selection. In this work, two methods of matching peaks between chromatograms were explored and an optimal pair of chromatography columns was selected for 2D-HPLC. First, a series of 17 antioxidants were selected as an analogue for a coffee extract. The predicted orthogonality of the standards was 39%, according to the fractional surface coverage 'bins' method, which was close to the actual space utilisation of the standard mixture, 44%. Moreover, the orthogonality for the 2D-HPLC of coffee matched the predicted value of 38%. The second method employed a complex sample matrix of urine to optimise the column selections. Seven peaks were confidently matched between chromatograms by comparing relative peak areas of two detection strategies: UV absorbance and potassium permanganate chemiluminescence. It was found that the optimal combinations had an orthogonality of 35% while the actual value was closer to 30%. PMID:25618686

  2. Screening triclocarban and its transformation products in river sediment using liquid chromatography and high resolution mass spectrometry.

    Science.gov (United States)

    Souchier, Marine; Benali-Raclot, Dalel; Benanou, David; Boireau, Véronique; Gomez, Elena; Casellas, Claude; Chiron, Serge

    2015-01-01

    An analytical method was developed and validated for the target screening of triclosan (TCS), triclocarban (TCC) and its lesser and higher chlorinated congeners namely, 4,4'-dichlorocarbanilide (DCC) 3,3',4,4'-tetrachlorocarbanilide (3-Cl-TCC) and 2,3',4,4'-tetrachlorocarbanilide (2-Cl-TCC) in river sediment. Sediment samples were extracted by pressurized liquid extraction and quantification and identification of target compounds were carried by liquid chromatography high resolution mass spectrometry (LC-HRMS). The overall method recoveries were 89% with relative standard deviations below 6%. Method detection limits ranged from 0.01 to 0.12 ng/g. The usefulness of the method was demonstrated on sediment samples collected downstream of three wastewater treatment plants in an attempt to provide with a set of occurrence data of these biocides in France and for a better understanding of their fate in river. Major results are the following: TCC, DCC and 3-Cl-TCC were ubiquitously detected demonstrating that these emerging contaminants have been probably overlooked in France. Reductive dechlorination of TCC into DCC was also ubiquitous but predominated in anoxic sediment. 3-Cl-TCC is probably more persistent than TCC and LC-HRMS enabled the detection and identification of a suite of other chlorinated biocides in river sediment. PMID:25260165

  3. [Determination of gossypol in edible vegetable oil with high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Zhang, Wenhua; Huang, Chaoqun; Xie, Wen; Shen, Li

    2014-06-01

    A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of gossypol in edible vegetable oil. The sample was extracted with ethyl alcohol by vortex-excited oscillation. The extract was cleaned up by 0.22 microm filter membrane and centrifuged for 5 min at 4 000 r/min after standing in a fridge at 4 degrees C for 30 min. The compound was separated on a C18 column (100 mm x 2.1 mm, 3.5 microm) with acetonitrile and 1% (v/v) formic acid aqueous solution as mobile phase. The detection of gossypol was carried out by LC-MS/MS with positive electrospray ionization under multiple reaction monitoring (MRM) mode using external standard method. The limits of quantification (S/N > 10) of gossypol in edible vegetable oil was 1 mg/kg. The recoveries were from 87.4% to 100% at the spiked levels of 1, 2, 200 mg/kg of gossypol in edible vegetable oil with the relative standard deviations (RSDs) between 3.9% and 12.2%. The method, with high sensitivity, good precision and high recovery, was suitable for the confirmation and quantification of gossypol residue in edible vegetable oil. PMID:25269254

  4. High-performance liquid chromatography method validation for determination of tetracycline residues in poultry meat

    Directory of Open Access Journals (Sweden)

    Vikas Gupta

    2014-01-01

    Full Text Available Background: In this study, a method for determination of tetracycline (TC residues in poultry with the help of high-performance liquid chromatography technique was validated. Materials and Methods: The principle step involved in ultrasonic-assisted extraction of TCs from poultry samples by 2 ml of 20% trichloroacetic acid and phosphate buffer (pH 4, which gave a clearer supernatant and high recovery, followed by centrifugation and purification by using 0.22 μm filter paper. Results: Validity study of the method revealed that all obtained calibration curves showed good linearity (r2 > 0.999 over the range of 40-4500 ng. Sensitivity was found to be 1.54 and 1.80 ng for oxytetracycline (OTC and TC. Accuracy was in the range of 87.94-96.20% and 72.40-79.84% for meat. Precision was lower than 10% in all cases indicating that the method can be used as a validated method. Limit of detection was found to be 4.8 and 5.10 ng for OTC and TC, respectively. The corresponding values of limit of quantitation were 11 and 12 ng. Conclusion: The method reliably identifies and quantifies the selected TC and OTC in the reconstituted poultry meat in the low and sub-nanogram range and can be applied in any laboratory.

  5. High-performance liquid chromatography of quinoidal imminium compounds derived from triphenylmethanes

    Science.gov (United States)

    Abidi, S.L.

    1983-01-01

    A series of eleven p-aminotriphenylmethane dyes have been studied by high-performance liquid chromatography (HPLC). The combined use of HPLC and spectrophotometry permits specific detection of these compounds in the visible range around 600 nm. As the high affinity of the imminium cations for the active sites of the hydrocarbonaceous stationary phase has presented difficulties for reversed-phase HPLC with pure solvents, organic electrolytes were added to the mobile phase to facilitate the elution of the components with improved selectivity, sensitivity (minimum detection limit, 0.1 μg/ml), and peak symmetry. The effects of chromatographic variables on the component retentivity were investigated. Retention times of the dye analytes decreased with increasing concentration of the added ionic reagent and with decreasing number of the hydrophobic alkyl substituents on the nitrogen atom. The influence of pH on the retention parameters appears to parallel that observed previously for cationic quaternary ammonium compounds. Among the acidic reagents employed, naphthalenesulfonic acid yielded the most satisfactory results. The use of binary electrolyte systems invariably improved the chromatographic behavior of the imminium solutes analyzed. Results obtained with two different octadecylsilica columns have been compared.

  6. A high-performance liquid chromatography method for determining transition metal content in proteins.

    Science.gov (United States)

    Atanassova, Anelia; Lam, Robert; Zamble, Deborah B

    2004-12-01

    Transition metals are common components of cellular proteins and the detailed study of metalloproteins necessitates the identification and quantification of bound metal ions. Screening for metals is also an informative step in the initial characterization of the numerous unknown and unclassified proteins now coming through the proteomic pipeline. We have developed a high-performance liquid chromatography method for the quantitative determination of the most prevalent biological transition metals: manganese, iron, cobalt, nickel, copper, and zinc. The method is accurate and simple and can be adapted for automated high-throughput studies. The metal analysis involves acid hydrolysis to release the metal ions into solution, followed by ion separation on a mixed-bead ion-exchange column and absorbance detection after postcolumn derivatization with the metallochromic indicator 4-(2-pyridylazo)resorcinol. The potential interferences by common components of protein solutions were investigated. The metal content of a variety of metalloproteins was analyzed and the data were compared to data obtained from inductively coupled plasma-atomic emission spectroscopy. The sensitivity of the assay allows for the detection of 0.1-0.8 nmol, depending on the metal. The amount of protein required is governed by the size of the protein and the fraction of protein with metal bound. For routine analysis 50 microg was used but for many proteins 10 microg would be sufficient. The advantages, disadvantages, and possible applications of this method are discussed. PMID:15519577

  7. The MAREDAT global database of high performance liquid chromatography marine pigment measurements

    Directory of Open Access Journals (Sweden)

    J. Peloquin

    2013-03-01

    Full Text Available A global pigment database consisting of 35 634 pigment suites measured by high performance liquid chromatography was assembled in support of the MARine Ecosytem DATa (MAREDAT initiative. These data originate from 136 field surveys within the global ocean, were solicited from investigators and databases, compiled, and then quality controlled. Nearly one quarter of the data originates from the Laboratoire d'Océanographie de Villefranche (LOV, with an additional 17% and 19% stemming from the US JGOFS and LTER programs, respectively. The MAREDAT pigment database provides high quality measurements of the major taxonomic pigments including chlorophylls a and b, 19'-butanoyloxyfucoxanthin, 19'-hexanoyloxyfucoxanthin, alloxanthin, divinyl chlorophyll a, fucoxanthin, lutein, peridinin, prasinoxanthin, violaxanthin and zeaxanthin, which may be used in varying combinations to estimate phytoplankton community composition. Quality control measures consisted of flagging samples that had a total chlorophyll a concentration of zero, had fewer than four reported accessory pigments, or exceeded two standard deviations of the log-linear regression of total chlorophyll a with total accessory pigment concentrations. We anticipate the MAREDAT pigment database to be of use in the marine ecology, remote sensing and ecological modeling communities, where it will support model validation and advance our global perspective on marine biodiversity. The original dataset together with quality control flags as well as the gridded MAREDAT pigment data may be downloaded from PANGAEA: http://doi.pangaea.de/10.1594/PANGAEA.793246.

  8. The MAREDAT global database of high performance liquid chromatography marine pigment measurements

    Science.gov (United States)

    Peloquin, J.; Swan, C.; Gruber, N.; Vogt, M.; Claustre, H.; Ras, J.; Uitz, J.; Barlow, R.; Behrenfeld, M.; Bidigare, R.; Dierssen, H.; Ditullio, G.; Fernandez, E.; Gallienne, C.; Gibb, S.; Goericke, R.; Harding, L.; Head, E.; Holligan, P.; Hooker, S.; Karl, D.; Landry, M.; Letelier, R.; Llewellyn, C. A.; Lomas, M.; Lucas, M.; Mannino, A.; Marty, J.-C.; Mitchell, B. G.; Muller-Karger, F.; Nelson, N.; O'Brien, C.; Prezelin, B.; Repeta, D.; Smith, W. O., Jr.; Smythe-Wright, D.; Stumpf, R.; Subramaniam, A.; Suzuki, K.; Trees, C.; Vernet, M.; Wasmund, N.; Wright, S.

    2013-03-01

    A global pigment database consisting of 35 634 pigment suites measured by high performance liquid chromatography was assembled in support of the MARine Ecosytem DATa (MAREDAT) initiative. These data originate from 136 field surveys within the global ocean, were solicited from investigators and databases, compiled, and then quality controlled. Nearly one quarter of the data originates from the Laboratoire d'Océanographie de Villefranche (LOV), with an additional 17% and 19% stemming from the US JGOFS and LTER programs, respectively. The MAREDAT pigment database provides high quality measurements of the major taxonomic pigments including chlorophylls a and b, 19'-butanoyloxyfucoxanthin, 19'-hexanoyloxyfucoxanthin, alloxanthin, divinyl chlorophyll a, fucoxanthin, lutein, peridinin, prasinoxanthin, violaxanthin and zeaxanthin, which may be used in varying combinations to estimate phytoplankton community composition. Quality control measures consisted of flagging samples that had a total chlorophyll a concentration of zero, had fewer than four reported accessory pigments, or exceeded two standard deviations of the log-linear regression of total chlorophyll a with total accessory pigment concentrations. We anticipate the MAREDAT pigment database to be of use in the marine ecology, remote sensing and ecological modeling communities, where it will support model validation and advance our global perspective on marine biodiversity. The original dataset together with quality control flags as well as the gridded MAREDAT pigment data may be downloaded from PANGAEA: http://doi.pangaea.de/10.1594/PANGAEA.793246.

  9. [Determination of gossypol in edible vegetable oil with high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Zhang, Wenhua; Huang, Chaoqun; Xie, Wen; Shen, Li

    2014-06-01

    A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of gossypol in edible vegetable oil. The sample was extracted with ethyl alcohol by vortex-excited oscillation. The extract was cleaned up by 0.22 microm filter membrane and centrifuged for 5 min at 4 000 r/min after standing in a fridge at 4 degrees C for 30 min. The compound was separated on a C18 column (100 mm x 2.1 mm, 3.5 microm) with acetonitrile and 1% (v/v) formic acid aqueous solution as mobile phase. The detection of gossypol was carried out by LC-MS/MS with positive electrospray ionization under multiple reaction monitoring (MRM) mode using external standard method. The limits of quantification (S/N > 10) of gossypol in edible vegetable oil was 1 mg/kg. The recoveries were from 87.4% to 100% at the spiked levels of 1, 2, 200 mg/kg of gossypol in edible vegetable oil with the relative standard deviations (RSDs) between 3.9% and 12.2%. The method, with high sensitivity, good precision and high recovery, was suitable for the confirmation and quantification of gossypol residue in edible vegetable oil.

  10. Analysis of the Constituents in “Zhu She Yong Xue Shuan Tong” by Ultra High Performance Liquid Chromatography with Quadrupole Time-of-Flight Mass Spectrometry Combined with Preparative High Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Lin-Lin Wang

    2015-11-01

    Full Text Available “Zhu She Yong Xue Shuan Tong” lyophilized powder (ZSYXST, consists of a series of saponins extracted from Panax notoginseng, which has been widely used in China for the treatment of strokes. In this study, an ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF/MS combined with preparative high performance liquid chromatography (PHPLC method was developed to rapidly identify both major and minor saponins in ZSYXST. Some high content components were removed through PHPLC in order to increase the sensitivity of the trace saponins. Then, specific characteristic fragment ions in both positive and negative mode were utilized to determine the types of aglycone, saccharide, as well as the saccharide chain linkages. As a result, 94 saponins, including 20 pairs of isomers and ten new compounds, which could represent higher than 98% components in ZSYXST, were identified or tentatively identified in commercial ZSYXST samples.

  11. Multi-detection of corticosteroids in sports doping and veterinary control using high-resolution liquid chromatography/time-of-flight mass spectrometry

    NARCIS (Netherlands)

    Touber, M.E.; Engelen, M.C.; Georgakopoulus, C.; Rhijn, van J.A.; Nielen, M.W.F.

    2007-01-01

    A liquid chromatography/time-of-flight mass spectrometry (LC/TOFMS) method was developed using the latest high-resolution LC column technology, the ultra performance liquid chromatography (UPLC (TM)), and electrospray ionization (ESI) in the positive ion mode. Gradient UPLC separation conditions wer

  12. Evaluation of aminoacids in irradiated beans (Vigna unguiculata (L.) Walp) by high performance liquid chromatography (HPLC)

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Keila S. Cople; Souza, Luciana B.; Coelho, Maysa J.; Lima, Antonio L. Santos; Hernandes, Nilber K. [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Secao de Engenharia Nuclear]. E-mail: keila@ime.eb.br; Godoy, Ronoel L.O. [EMBRAPA Agroindustria de Alimentos, Rio de Janeiro, RJ (Brazil)]. E-mail: ronoel@ctaa.embrapa.br

    2007-07-01

    Fradinho-bean (Vigna unguiculata (L.) Walp) is originated from Africa and is known in Brazil as 'caupi', 'corda' or 'macassar'. It is grown in the interior of Northeast Brazil (semi-arid region) and can be found in parts of the North, being one of the most important components of people's diet in those regions. The Northeast area produces around 429,375 ton of fradinho-bean per year. Leguminous plants are very important sources of proteins, vitamins, carbohydrates and minerals. This kind of bean is an excellent source of proteins (around 23- 25% of its nutritional content), being superior to regular beans (Phaseolus vulgaris). The irradiation process is an alternative to avoid post-harvesting losses, without changing the nutritional value of food. This study has the objective to evaluate the effect of different gamma irradiation doses (0.0; 0.5; 1.0; 2.5; 5.0 and 10.0 kGy) on aminoacid content of fradinho-bean by high performance liquid chromatography (HPLC) and the accompanying of the grains during storage time of 6 months. After irradiation, the bean grains went through a milling process in order to make flour for posterior extraction. A liquid chromatographer Waters, model Alliance 2695, with fluorescent detector Waters 2475, having a mobile phase with gradient elution of sodium acetate. acetonitrile and Milli-Q water, was employed. The flux used was 1 mL/min and the injection volume of 10 {mu}L. The column (C 18 150.0 x 3.9 mm) was kept at 36 deg C. The results show that gamma irradiation is a promise process for fradinho bean during conservation storage time of 6 months, until the dose of 10.0 kGy. Even the most radio-sensitive aminoacids like aromatics and basic lateral chains were preserved. (author)

  13. Ionic liquid foam floatation coupled with ionic liquid dispersive liquid-liquid microextraction for the separation and determination of estrogens in water samples by high-performance liquid chromatography with fluorescence detection.

    Science.gov (United States)

    Zhang, Rui; Wang, Chuanliu; Yue, Qiaohong; Zhou, Tiecheng; Li, Na; Zhang, Hanqi; Hao, Xiaoke

    2014-11-01

    An ionic liquid foam floatation coupled with ionic liquid dispersive liquid-liquid microextraction method was proposed for the extraction and concentration of 17-α-estradiol, 17-β-estradiol-benzoate, and quinestrol in environmental water samples by high-performance liquid chromatography with fluorescence detection. 1-Hexyl-3-methylimidazolium tetrafluoroborate was applied as foaming agent in the foam flotation process and dispersive solvent in microextraction. The introduction of the ion-pairing and salting-out agent NH4 PF6 was beneficial to the improvement of recoveries for the hydrophobic ionic liquid phase and analytes. Parameters of the proposed method including concentration of 1-hexyl-3-methylimidazolium tetrafluoroborate, flow rate of carrier gas, floatation time, types and concentration of ionic liquids, salt concentration in samples, extraction time, and centrifugation time were evaluated. The recoveries were between 98 and 105% with relative standard deviations lower than 7% for lake water and well water samples. The isolation of the target compounds from the water was found to be efficient, and the enrichment factors ranged from 4445 to 4632. This developing method is free of volatile organic solvents compared with regular extraction. Based on the unique properties of ionic liquids, the application of foam floatation, and dispersive liquid-liquid microextraction was widened. PMID:25146581

  14. Development of a high-performance liquid chromatography - Tandem mass spectrometry urinary pterinomics workflow.

    Science.gov (United States)

    Burton, Casey; Shi, Honglan; Ma, Yinfa

    2016-07-13

    Pteridines have evoked considerable interest from the scientific community owing to their prominent roles in human health and disease. The availability of analytical methodologies suitable for comprehensive pteridine profiling, termed here as "pterinomics", has been limited by inconsistent sample preparation and the exclusion of lesser studied pteridine derivatives. In response, the present study describes a new pterinomics workflow using a high-performance liquid chromatography - tandem mass spectrometry (HPLC-MS/MS) methodology for the simultaneous analysis of 15 pteridine derivatives including four structural isomers, marking the largest quantitative pteridine panel that has been studied to-date. The validated method possessed excellent sensitivity with method detection limits (0.025 μg L(-1) to 0.5 μg L(-1)) that were comparable or superior to existing techniques. Spiked recovery studies demonstrated the technique was both accurate (88-112%) and precise (RSD: 0-6%). A comparative study of commonly used oxidative pretreatments, including triiodide, permanganate, and manganese dioxide, revealed that the oxidative mechanisms were inefficient, complex, and concentration dependent. Finally, 50 clinical urine specimens were examined with the new technique wherein 10 pteridine derivatives were quantified and population ranges have been given. This technique can be used to examine pteridine molecular epidemiology and biochemistry to support related research applications, and may further be readily extended to include additional pteridine derivatives and biological matrices for specific applications. PMID:27237839

  15. [Determination of six pesticides in milk using cloud point extraction-high performance liquid chromatography].

    Science.gov (United States)

    Wang, Jian; Cui, Yanmei; Liu, Wei; Yang, Mingmin; Chen, Jianbo

    2007-11-01

    The feasibility of employing cloud point extraction (CPE) as extraction and preconcentration method for the recovery of herbicides from milk samples followed by high performance liquid chromatography (HPLC) analysis is demonstrated. An aqueous surfactant solution containing 60 g/L Tween 20 or Triton X-100 was heated with an appropriate concentration of (NH4)2SO4 or NaCl for the extraction of herbicides. The extract was analyzed by HPLC subsequently. Six herbicides in milk were analyzed simultaneously. The results showed that the linear dynamic ranges of detection were 20 - 10 000 microg/L for tralkoxydim, metribuzin and bromoxynil, 30 - 10 000 microg/L for mefenacet, and 50 - 10 000 microg/L for bensulfuron-methyl and nicosulfuron. The correlation coefficients were 0.998 1 - 0.999 7. The average recoveries of the six herbicides ranged from 85.09% to 96.74%. The relative standard deviations for the six herbicides were in the range of 1.90% - 3.98%. The limits of detection for the six pesticides were lower than the maximum residue limits (MRL) of China. The results indicate that the method is easier, faster, sensitive and produces less pollutants. PMID:18257303

  16. Advances in liquid chromatography-high-resolution mass spectrometry for quantitative and qualitative environmental analysis.

    Science.gov (United States)

    Aceña, Jaume; Stampachiacchiere, Serena; Pérez, Sandra; Barceló, Damià

    2015-08-01

    This review summarizes the advances in environmental analysis by liquid chromatography-high-resolution mass spectrometry (LC-HRMS) during the last decade and discusses different aspects of their application. LC-HRMS has become a powerful tool for simultaneous quantitative and qualitative analysis of organic pollutants, enabling their quantitation and the search for metabolites and transformation products or the detection of unknown compounds. LC-HRMS provides more information than low-resolution (LR) MS for each sample because it can accurately determine the mass of the molecular ion and its fragment ions if it can be used for MS-MS. Another advantage is that the data can be processed using either target analysis, suspect screening, retrospective analysis, or non-target screening. With the growing popularity and acceptance of HRMS analysis, current guidelines for compound confirmation need to be revised for quantitative and qualitative purposes. Furthermore, new commercial software and user-built libraries are required to mine data in an efficient and comprehensive way. The scope of this critical review is not to provide a comprehensive overview of the many studies performed with LC-HRMS in the field of environmental analysis, but to reveal its advantages and limitations using different workflows. PMID:26138893

  17. Determination of acrylamide monomer in polyacrylamide degradation studies by high-performance liquid chromatography.

    Science.gov (United States)

    Ver Vers, L M

    1999-12-01

    A high-performance liquid chromatography method using C18 and ion-exchange columns in series is developed for the determination of acrylamide and acrylic acid monomers in polymeric samples. The C18 column acts as a guard column, trapping surfactants and impurities and retaining the nonionic species. The ion-exchange column then separates the monomers according to their respective ionic strengths. This method has been proven in the laboratory to work successfully for all types of acrylamide/acrylic acid polymers and matrices. Detection limits for both monomers can be achieved in the parts-per-billion range. The method is used to study the possible degradation of polyacrylamide to acrylamide monomer in the presence of glyphosate (a herbicide) and sunlight. Polyacrylamide is used as a spray drift reduction aid in combination with glyphosate. In normal applications, the polymer and herbicide are in contact with each other in the presence of sunlight. The results show that the polymer does not degrade to acrylamide in the presence of glyphosate or sunlight or any combination of the two. It is also observed that glyphosate influences the solubility of polyacrylamide, and care must be used when combining the two.

  18. Arsenic speciation in soil using high performance liquid chromatography/inductively coupled plasma/mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bass, D.A.; Yaeger, J.S.; Parish, K.J.; Crain, J.S.; Kiely, J.T.; Gowdy, M.J. [Argonne National Lab., IL (United States); Mohrman, G.B.; Besmer, M.G. [Rocky Mountain Arsenal, Commerce City, CO (United States)

    1996-08-01

    A method has been developed to identify and quantify As(III), As(V), and organoarsenic compounds in soil samples from the Rocky Mountain Arsenal (RMA) by high performance liquid chromatography/inductively coupled plasma/mass spectrometry (HPLC/ICP/MS). The soils were extracted using tetrabutylammonium hydroxide (TBAH) and sonication. The percentages of As(III), As(V), and organoarsenic species extracted from soil samples were 30, 50, and 100 respectively. The arsenic species were not altered during the extraction process. They were separated by reversed-phase, ion-pairing, HPLC using a microbore Inertsil-ODS{trademark} column. The HPLC column effluent was introduced into an ICP/MS system using a direct injection nebulizer (DIN). Detection limits of less than 1 pg were readily obtained for each arsenic species. Internal standards are recommended to increase accuracy and precision. Soil samples spiked with arsenic oxide, sodium arsenate, dimethylarsinic acid (DMAA), and chlorovinyl arsenious acid (CVAA) were extracted, identified and quantified with the HPLC/ICP/MS system. The soil samples were analyzed in support of the analytical needs of a thermal desorption treatability study being conducted at the RMA.

  19. [Determination of six pesticides in milk using cloud point extraction-high performance liquid chromatography].

    Science.gov (United States)

    Wang, Jian; Cui, Yanmei; Liu, Wei; Yang, Mingmin; Chen, Jianbo

    2007-11-01

    The feasibility of employing cloud point extraction (CPE) as extraction and preconcentration method for the recovery of herbicides from milk samples followed by high performance liquid chromatography (HPLC) analysis is demonstrated. An aqueous surfactant solution containing 60 g/L Tween 20 or Triton X-100 was heated with an appropriate concentration of (NH4)2SO4 or NaCl for the extraction of herbicides. The extract was analyzed by HPLC subsequently. Six herbicides in milk were analyzed simultaneously. The results showed that the linear dynamic ranges of detection were 20 - 10 000 microg/L for tralkoxydim, metribuzin and bromoxynil, 30 - 10 000 microg/L for mefenacet, and 50 - 10 000 microg/L for bensulfuron-methyl and nicosulfuron. The correlation coefficients were 0.998 1 - 0.999 7. The average recoveries of the six herbicides ranged from 85.09% to 96.74%. The relative standard deviations for the six herbicides were in the range of 1.90% - 3.98%. The limits of detection for the six pesticides were lower than the maximum residue limits (MRL) of China. The results indicate that the method is easier, faster, sensitive and produces less pollutants.

  20. Chemical fingerprint analysis of Gentianae Radix et Rhizoma by high-performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Baozhong Duan

    2012-02-01

    Full Text Available Gentianae Radix et Rhizoma (also called “Longdan” in Chinese is commonly used for eliminating damp-heat and quenching the fire of liver and gall bladder in traditional Chinese medicine. In this study, a novel and reliable method using high-performance liquid chromatography (HPLC was developed both for quantitative analysis of four bioactive compounds (loganic acid, swertiamarin, gentiopicroside and sweroside and chemical fingerprint analysis of “Longdan”. In quantitative analysis, four compounds showed good regressions (R2>0.9987 within the test ranges and the recovery of the method was in the range 97.61−102.49%. In fingerprint analysis, ten characteristic peaks were selected to evaluate the similarities of the crude drugs, and the HPLC chromatograms of twenty samples from different regions of China showed similar patterns. The results demonstrated that the combination of the quantitative and chromatographic fingerprint analyses offered an efficient way to evaluate the quality consistency of Gentianae Radix et Rhizoma.

  1. Preparation and Characterization of a New Quercetin-bonded Stationary Phase for High Performance Liquid Chromatography

    Institute of Scientific and Technical Information of China (English)

    李来生; 方奕珊; 陈红; 张杨

    2012-01-01

    A quercetin-bonded silica gel stationary phase (QUSP) containing natural flavonoid ligand was first prepared via γ-glycidoxypropyltrimethoxysilane (KH-560) as a coupling reagent for high-performance liquid chromatography. Its chemical structure was characterized by Fourier infrared spectroscopy, elemental analysis, thermal thermogravimetry and 13C cross polarization/magic angle spinning nuclear magnetic resonance (CP/MAS NMR). The chromatographic property of QUSP was systematically evaluated by using neutral, basic and acidic aromatic com- pounds as probes. In order to clarify its retention mechanism, a comparative study of QUSP with conventional oc- tadecylsilyl-bonded stationary phase (ODS) was also carried out under the same conditions. The results showed that the new quercetin-bonded phase exhibited an excellent reversed-phase chromatographic property with relatively weak hydrophobicity. However, it has an advantage over ODS in the fast separation of polar aromatic compounds because the quercetin ligand could provide various sites besides hydrophobicity, such as hydrogen bonding, dipole-dipole, n-n staking and charge transfer interactions. QUSP was performed in the baseline separations of ion- ized polar basic or acidic compounds, including pyridines, anilines, pyrimidines, purines and phenols with symmet- ric peak shape in common mobile phases without buffer salt within relatively short time. The natural ligands from herbs are readily available and contain a variety of active sites, which facilitate the exploration of industrial chromatographic separation materials for green products.

  2. Simultaneous determination of eleven characteristic lignans in Schisandra chinensis by high-performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Junyang Hu

    2013-01-01

    Full Text Available Background: Schisandra chinensis, one of the well-known traditional Chinese herbal medicines, is derived from the dry ripe fruits of Schisandra chinensis (Turcz. Baill. according to the 9th China Pharmacopeia. Lignans are the main components isolated from extracts of S. chinensis and their content varies depending on where S. chinensis was collected. We have established a qualitative and quantitative method based on the bioactive lignans for control of the quality of S. chinensis from different sources. Materials and Methods: To develop a high-performance liquid chromatography method, an Elite ODS C18 column (250 mm Χ 4.6 mm, 5μm at a column temperature of 30°C and flow rate of 1.0ml/min using acetonitrile (A and water (B as the mobile phase with a linear gradient and the peaks were monitored at 217 nm. Results: All calibration curves showed good linearity (r ≥ 0.9995 within test ranges. This method showed good repeatability for the quantification of these eleven components in S. chinensis with intra- and inter-day relative standard deviations less than 0.43% and 1.21%, respectively. In the recovery test, results of accuracy ranged from 99.51% to 101.31% with RSD values less than 2.68%, Conclusion: The validated method can be successfully applied to quantify the eleven investigated components in 22 samples of S. chinensis from different sources.

  3. Quantitation of aflatoxins in walnut kernels by high-performance liquid chromatography with fluorescence detection.

    Science.gov (United States)

    Kabak, Bulent

    2014-01-01

    A total of 85 walnut samples collected between October 2012 and April 2013 in different provinces of Turkey were analysed for the presence of aflatoxins (AFs). The method involved methanol-water extraction, clean-up with immunoaffinity columns and a sensitive high-performance liquid chromatography coupled with fluorescence detection after post-column derivatisation. The method was validated for selectivity, linearity, trueness, precision, limit of detection and limit of quantification (LOQ), which met the performance criteria as set by EC regulation No. 401/2006. LOQs were 0.07, 0.04, 0.09 and 0.05 µg kg(-1) for AFB1, AFB2, AFG1 and AFG2, respectively. AFs were present in 9.4% of walnut samples (8/85) at total AFs levels ranging from 0.09 to 15.4 µg kg(-1). Only one of eight walnut samples exceeded the European Union limit of 2 and 4 µg kg(-1) for AFB1 and total AFs, respectively.

  4. Analysis of Fluconazole in Human Urine Sample by High Performance Liquid Chromatography Method

    Science.gov (United States)

    Hermawan, D.; Ali, N. A. Md; Ibrahim, W. A. Wan; Sanagi, M. M.

    2013-04-01

    A method for determination of fluconazole, antifungal drug in human urine by using reversed-phased high performance liquid chromatography (RP-HPLC) with ultraviolet (UV) detector was developed. Optimization HPLC conditions were carried out by changing the flow rate and composition of mobile phase. The optimum separation conditions at a flow rate 0.85 mL/min with a composition of mobile phase containing methanol:water (70:30, v/v) with UV detection at a wavelength 254 nm was able to analyze fluconazole within 3 min. The excellent linearity was obtained in the range of concentration 1 to 10 μg/mL with r2 = 0.998. The limit of detection (LOD) and limit of quantitation (LOQ) were 0.39 μg/mL and 1.28 μg/mL, respectively. Solid phase extraction (SPE) method using octadecylsilane (C18) as a sorbent was used to clean-up and pre-concentrated of the urine sample prior to HPLC analysis. The average recoveries of fluconazole in spiked urine sample was 72.4% with RSD of 3.21% (n=3).

  5. Simultaneous Determination of Potassium Sorbate and Sodium Benzoate in Doogh Using High Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    S. Sohrabvandi

    2015-09-01

    Full Text Available In this research, high performance liquid chromatography (HPLC as a simple and rapid technique was used for the determination of potassium sorbate and sodium benzoate in different brands of Doogh (typical Iranian drink based on fermented milk. The chromatographic separation was achieved with a C18 column (250 mm×4 I.D, 5 µm and one buffered mobile phase, acetate buffer (0.2 mol/L, pH4.4: acetonitrile (63:37 at a flow rate of 1 mL/min. The effluent was monitored at 235nm, respectively. The main affecting factors, such as Carrez solution amount, pH and centrifuge speed were optimized. Limits of detection (LODs were 1.823 for sorbic acid and 1.985 for benzoic acid. Relative standard deviations (RSDs for quintuplicate analyses were 4.4 for sorbic acid and 4.087 for benzoic acid. The method also showed good linearity in a range from 4 to 1000 mg/L with correlation coefficients (R2 of 0.990 for sorbic acid and 0.995 for benzoic acid. Recoveries for the two analytes were 80 for sorbic acid and 65 for benzoic acid. Comparing to the other techniques, the proposed method was significantly less time-consuming and had more acceptable accuracy, precision and interruption elimination in samples. The developed method was successfully used for the routine monitoring of benzoate and sorbate in Doogh.

  6. Identification of Dactylopius cochineal species with high-performance liquid chromatography and multivariate data analysis.

    Science.gov (United States)

    Serrano, Ana; Sousa, Micaela; Hallett, Jessica; Simmonds, Monique S J; Nesbitt, Mark; Lopes, João A

    2013-10-21

    Identification of American cochineal species (Dactylopius genus) can provide important information for the study of historical works of art, entomology, cosmetics, pharmaceuticals and foods. In this study, validated species of Dactylopius, including the domesticated cochineal D. coccus, were analysed by high-performance liquid chromatography with a diode array detector (HPLC-DAD) and submitted to multivariate data analysis, in order to discriminate the species and hence construct a reference library for a wide range of applications. Principal components analysis (PCA) and partial least squares discriminant analysis (PLSDA) models successfully provided accurate species classifications. This library was then applied to the identification of 72 historical insect specimens of unidentified species, mostly dating from the 19th century, and belonging to the Economic Botany Collection, Royal Botanic Gardens, Kew, England. With this approach it was possible to identify anomalies in how insects were labelled historically, as several of them were revealed not to be cochineal. Nevertheless, more than 85% of the collection was determined to be species of Dactylopius and the majority of the specimens were identified as D. coccus. These results have shown that HPLC-DAD, in combination with suitable chemometric methods, is a powerful approach for discriminating related cochineal species. PMID:23961534

  7. Determination of Flurbiprofen in Human Plasma by High-Performance Liquid Chromatography.

    Science.gov (United States)

    Yilmaz, Bilal; Erdem, Ali Fuat

    2015-10-01

    A simple high-performance liquid chromatography method has been developed for determination of flurbiprofen in human plasma. The method was validated on an Ace C18 column using UV detection. The mobile phase was acetonitrile-0.05 M potassium dihydrogen phosphate solution (60:40, v/v) adjusted to pH 3.5 with phosphoric acid. The calibration curve was linear between the concentration range of 0.10-5.0 μg/mL. Intra- and inter-day precision values for flurbiprofen in plasma were <4.47, and accuracy (relative error) was better than 3.67%. The extraction recoveries of flurbiprofen from human plasma were between 93.0 and 98.9%. The limits of detection and quantification of flurbiprofen were 0.03 and 0.10 μg/mL, respectively. In addition, this assay was applied to determine the pharmacokinetic parameters of flurbiprofen in six healthy Turkish volunteers who had been given 100 mg flurbiprofen.

  8. Determination of organic mercury species in soils by high-performance liquid chromatography with ultraviolet detection.

    Science.gov (United States)

    Hempel, M; Hintelmann, H; Wilken, R D

    1992-03-01

    Reversed-phase high-performance liquid chromatography with ultraviolet detection was optimized for the simultaneous separation and quantification of nine organic mercury compounds: methyl-, ethyl-, phenyl-, methoxyethyl-, ethoxyethyl-, benzoic and tolylmercury, mersalylic acid and nitromersol. The nine compounds were successfully separated on octadecylsilane columns (200 x 3 mm i.d.) by gradient elution with a methanol-water mixture ranging from 30 to 50% v/v. The detection limits for the various compounds are in the range 7.0-95.1 micrograms dm-3. For the extraction of five organomercurials from spiked soils, eight different extraction solutions were tested to differentiate between the total content and the available/soluble fraction of the analytes. Ammonium acetate solutions (1 mol dm-3) and water proved to be suitable agents for the estimation of the available and soluble fractions of methyl-, ethyl-, benzoic, methoxyethyl- and ethoxyethylmercury. For the determination of the total content of methyl- and benzoic mercury in soils, solutions of potassium iodide (1 mol dm-3)-ascorbic acid (0.1 mol dm-3) and oxalic acid (1 mol dm-3) provided recoveries in the ranges 53-81%. None of the solutions tested is suitable for the extraction of ethyl-, methoxyethyl- and ethoxyethylmercury.

  9. [Determination of clavulanic acid residue in milk by high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Yang, Gang; Huang, Xianhui; Guo, Chunna; Fang, Qiuhua; He, Limin

    2012-06-01

    An analytical method was developed for the determination of clavulanic acid (CLAV) in milk by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). A 2 g milk sample was deproteinized by ethanol. The supernatant was transferred into a pear-shaped bottle to be evaporated to about 0.5 mL, and the residue was dissolved with ammonium acetate solution. The sample was determined by HPLC-MS/MS after the purification. The chromatographic separation was achieved on a Luna 5u C8 column using 0.1% formic acid in water and acetonitrile as mobile phases with gradient elution. The identification of CLAV was carried out by MS/MS equipped with electrospray ionization in negative scanning and multiple reaction monitoring (MRM) modes. Matrix-matched calibration standard was used for the quantification. The calibration curve showed perfect linear in the range of 10 - 400 microg/kg with the correlation coefficient of 0.999. The limit of detection (LOD, S/N > or = 3) was 10 microg/kg in milk, and the limit of quantification (LOQ, S/N > or = 10) was 20 microg/kg. The mean recoveries varied from 80.00% to 91.25% at the four spiked levels of LOQ, 1/2MRL (the maximum residue limit), MRL, and 2MRL with the relative standard deviations of 5.60% -8.77%. In conclusion, the established method can be applied for the determination of CLAV residues in milk.

  10. Advances in liquid chromatography-high-resolution mass spectrometry for quantitative and qualitative environmental analysis.

    Science.gov (United States)

    Aceña, Jaume; Stampachiacchiere, Serena; Pérez, Sandra; Barceló, Damià

    2015-08-01

    This review summarizes the advances in environmental analysis by liquid chromatography-high-resolution mass spectrometry (LC-HRMS) during the last decade and discusses different aspects of their application. LC-HRMS has become a powerful tool for simultaneous quantitative and qualitative analysis of organic pollutants, enabling their quantitation and the search for metabolites and transformation products or the detection of unknown compounds. LC-HRMS provides more information than low-resolution (LR) MS for each sample because it can accurately determine the mass of the molecular ion and its fragment ions if it can be used for MS-MS. Another advantage is that the data can be processed using either target analysis, suspect screening, retrospective analysis, or non-target screening. With the growing popularity and acceptance of HRMS analysis, current guidelines for compound confirmation need to be revised for quantitative and qualitative purposes. Furthermore, new commercial software and user-built libraries are required to mine data in an efficient and comprehensive way. The scope of this critical review is not to provide a comprehensive overview of the many studies performed with LC-HRMS in the field of environmental analysis, but to reveal its advantages and limitations using different workflows.

  11. Quantitative Determination of Compounds from Akebia quinata by High-Performance Liquid Chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Yen, Nguyen; Thu, Nguyen; Zhao, Bing Tian; Woo, Mi Hee; Min, Byung Sun [Catholic Univ. of Daegu, Gyeongsan (Korea, Republic of); Lee, Jae Hyun [Dongguk Univ., Yongin (Korea, Republic of); Kim, Jeong Ah [Kyungpook National Univ., Daegu (Korea, Republic of); Son, Jong Keun [Yeungnam Univ., Gyeongsan (Korea, Republic of); Choi, Jae Sui [Pukyung National Univ., Busan (Korea, Republic of); Woo, Eun Rhan [Chosun Univ., Gwangju (Korea, Republic of)

    2014-07-15

    To provide the scientific corroboration of the traditional uses of Akebia quinata (Thunb.) Decne., a detailed analytical examination of A. quinata stems was carried out using a reversed-phase high performance liquid chromatography (RP-HPLC) method coupled to photodiode array detector (PDA) for the simultaneous determination of four phenolic substances; cuneataside D, 2-(3,4-dihydroxyphenyl)ethyl-O-β-D-glucopyranoside, 3-caffeoylquinic acid and calceolarioside B. Particular attention was focused on the main compound, 3-caffeoylquinic acid, which has a range of biological functions. In addition, 2-(3,4-dihydroxyphenyl)ethyl-O-β-D-glucopyranoside was considered as a discernible marker of A. quinata from its easy confuse plants. The contents of compounds 2 and 3 ranged from 0.72 to 2.68 mg/g and from 1.66 to 5.64 mg/g, respectively. The validation data indicated that this HPLC/PDA assay was used successfully to quantify the four phenolic compounds in A. quinata from different locations using relatively simple conditions and procedures. The pattern-recognition analysis data from 53 samples classified them into two groups, allowing discrimination between A. quinata and comparable herbs. The results suggest that the established HPLC/PDA method is suitable for quantitation and pattern-recognition analyses for a quality evaluation of this medicinal herb.

  12. Detection of HEMA in self-etching adhesive systems with high performance liquid chromatography

    Science.gov (United States)

    Panduric, V.; Tarle, Z.; Hameršak, Z.; Stipetić, I.; Matosevic, D.; Negovetić-Mandić, V.; Prskalo, K.

    2009-04-01

    One of the factors that can decrease hydrolytic stability of self-etching adhesive systems (SEAS) is 2-hydroxymethylmethacrylate (HEMA). Due to hydrolytic instability of acidic methacrylate monomers in SEAS, HEMA can be present even if the manufacturer did not include it in original composition. The aim of the study was to determine the presence of HEMA because of decomposition by hydrolysis of methacrylates during storage, resulting with loss of adhesion strength to hard dental tissues of the tooth crown. Three most commonly used SEAS were tested: AdheSE ONE, G-Bond and iBond under different storage conditions. High performance liquid chromatography analysis was performed on a Nucleosil C 18-100 5 μm (250 × 4.6 mm) column, Knauer K-501 pumps and Wellchrom DAD K-2700 detector at 215 nm. Data were collected and processed by EuroCrom 2000 HPLC software. Calibration curves were made related eluted peak area to known concentrations of HEMA (purchased from Fluka). The elution time for HEMA is 12.25 min at flow rate 1.0 ml/min. Obtained results indicate that no HEMA was present in AdheSE ONE because methacrylates are substituted with methacrylamides that seem to be more stable under acidic aqueous conditions. In all other adhesive systems HEMA was detected.

  13. Determination of Residual Acrylamide in Medical Polyacrylamide Hydrogel by High Performance Liquid Chromatography tandem Mass Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    WEI-WEI LI; HUI LI; ZHI-FEI LIU; QUN QIAO

    2009-01-01

    Objective To determine residual acrylamide in medical polyacrylamide hydrogel by high performance liquid chromatography tandem mass spectroscopy (HPLC-MS). Methods After 13C3 labeled acrylamide was added, the sample was extracted with water and then cleaned up with ExtrelutTM 20. The polyaerylamide hydrogel sample and 20 clinical cases were analyzed by HPLC-MS/MS and isotope dilution quantifying technique in selected reaction monitoring (SRM) mode. Results Acrylamide was separated from polyacrylamide hydrogel. The concentration of acrylamide in polyacrylamide hydrogel ranged from 3.9×109 to 3.1×108g/L in the 20 clinical cases. The peak area was favorable linear and the range was up to 3 000 μg/L. The recovery rate was 103.1% with a relative standard deviation (RSD) of 6.20%, when the mark level was 50 μg/L. Conclusion HPLC-MS is a rapid, accurate, and sensitive method for the determination of residual acrylamide in medical polyacrylamide hydrogel.

  14. Simultaneous determination of 11 preservatives in cosmetics by high-performance liquid chromatography.

    Science.gov (United States)

    Aoyama, Airin; Doi, Takahiro; Tagami, Takaomi; Kajimura, Keiji

    2014-10-01

    Preservatives prevent the growth of microorganisms in foods, pharmaceuticals and cosmetics. There exist numerous restrictions regarding the maximum allowable levels of preservatives in cosmetics. We analyzed 11 regulated preservatives in commercial cosmetics and manufacturers need to analyze their products for quality control purposes. However, methods used in previous studies to date have been inadequate for use by public institutions and manufacturers. Therefore, an effective, scalable method for the analysis of preservatives in cosmetics is required. We developed a novel method for the simultaneous determination of 11 regulated preservatives in cosmetics by high-performance liquid chromatography (HPLC). We applied the samples to a C18 column in a simple mobile phase (5 mmol/L ammonium formate solution and acetonitrile) with gradient elution at a flow rate of 1.0 mL/min at a single wavelength (230 nm). The correlation coefficients of the calibration curves were >0.997. The percent recoveries were 92.8-111.9% and the relative standard deviations were preservatives was >1.9. Because of the simple conditions for isolation and complete separation, the HPLC method can be effectively applied to the analysis of preservatives in commercially retailed cosmetics.

  15. [Simultaneous determination of nitrofurantoin and furazolidone in cosmetics using high performance liquid chromatography].

    Science.gov (United States)

    Zhang, Qing; Wang, Chao; Wang, Xing; Wu, Ting; Ma, Qiang

    2009-03-01

    A method was developed for the simultaneous determination of nitrofurantoin and furazolidone in cosmetics using reversed-phase high performance liquid chromatography. Cosmetics samples of various types, including lotion, cream, emollient, waterpowder and lipstick, were extracted under ultrasonication with acetonitrile-methanol (1:1, v/v). A Kromasil C18 analytical column (250 mm x 4.6 mm, 5 microm) was used for the separation at 25 degrees C. Acetonitrile-0.4% acetic acid (30:70, v/v) was used as the mobile phase at a flow rate of 1.0 mL/min. The detection was performed at 365 nm by a diode array detector. The quantitative analysis was performed using external standard calibration curve. The linear ranges for nitrofurantoin and furazolidone were 0.1-20 mg/L (r = 0.9999). The average recoveries were 88.0%-104.6% with the relative standard deviations of 0.5%-4.8%. The method is convenient, rapid, reliable and suitable for the determination of nitrofurantoin and furazolidone in cosmetics. PMID:19626857

  16. Quantitation of triacylglycerols in edible oils by off-line comprehensive two-dimensional liquid chromatography-atmospheric pressure chemical ionization mass spectrometry using a single column.

    Science.gov (United States)

    Wei, Fang; Hu, Na; Lv, Xin; Dong, Xu-Yan; Chen, Hong

    2015-07-24

    In this investigation, off-line comprehensive two-dimensional liquid chromatography-atmospheric pressure chemical ionization mass spectrometry using a single column has been applied for the identification and quantification of triacylglycerols in edible oils. A novel mixed-mode phenyl-hexyl chromatographic column was employed in this off-line two-dimensional separation system. The phenyl-hexyl column combined the features of traditional C18 and silver-ion columns, which could provide hydrophobic interactions with triacylglycerols under acetonitrile conditions and can offer π-π interactions with triacylglycerols under methanol conditions. When compared with traditional off-line comprehensive two-dimensional liquid chromatography employing two different chromatographic columns (C18 and silver-ion column) and using elution solvents comprised of two phases (reversed-phase/normal-phase) for triacylglycerols separation, the novel off-line comprehensive two-dimensional liquid chromatography using a single column can be achieved by simply altering the mobile phase between acetonitrile and methanol, which exhibited a much higher selectivity for the separation of triacylglycerols with great efficiency and rapid speed. In addition, an approach based on the use of response factor with atmospheric pressure chemical ionization mass spectrometry has been developed for triacylglycerols quantification. Due to the differences between saturated and unsaturated acyl chains, the use of response factors significantly improves the quantitation of triacylglycerols. This two-dimensional liquid chromatography-mass spectrometry system was successfully applied for the profiling of triacylglycerols in soybean oils, peanut oils and lord oils. A total of 68 triacylglycerols including 40 triacylglycerols in soybean oils, 50 triacylglycerols in peanut oils and 44 triacylglycerols in lord oils have been identified and quantified. The liquid chromatography-mass spectrometry data were analyzed

  17. Quantitation of triacylglycerols in edible oils by off-line comprehensive two-dimensional liquid chromatography-atmospheric pressure chemical ionization mass spectrometry using a single column.

    Science.gov (United States)

    Wei, Fang; Hu, Na; Lv, Xin; Dong, Xu-Yan; Chen, Hong

    2015-07-24

    In this investigation, off-line comprehensive two-dimensional liquid chromatography-atmospheric pressure chemical ionization mass spectrometry using a single column has been applied for the identification and quantification of triacylglycerols in edible oils. A novel mixed-mode phenyl-hexyl chromatographic column was employed in this off-line two-dimensional separation system. The phenyl-hexyl column combined the features of traditional C18 and silver-ion columns, which could provide hydrophobic interactions with triacylglycerols under acetonitrile conditions and can offer π-π interactions with triacylglycerols under methanol conditions. When compared with traditional off-line comprehensive two-dimensional liquid chromatography employing two different chromatographic columns (C18 and silver-ion column) and using elution solvents comprised of two phases (reversed-phase/normal-phase) for triacylglycerols separation, the novel off-line comprehensive two-dimensional liquid chromatography using a single column can be achieved by simply altering the mobile phase between acetonitrile and methanol, which exhibited a much higher selectivity for the separation of triacylglycerols with great efficiency and rapid speed. In addition, an approach based on the use of response factor with atmospheric pressure chemical ionization mass spectrometry has been developed for triacylglycerols quantification. Due to the differences between saturated and unsaturated acyl chains, the use of response factors significantly improves the quantitation of triacylglycerols. This two-dimensional liquid chromatography-mass spectrometry system was successfully applied for the profiling of triacylglycerols in soybean oils, peanut oils and lord oils. A total of 68 triacylglycerols including 40 triacylglycerols in soybean oils, 50 triacylglycerols in peanut oils and 44 triacylglycerols in lord oils have been identified and quantified. The liquid chromatography-mass spectrometry data were analyzed

  18. Temperature-programmed high-performance liquid chromatography coupled to isotope ratio mass spectrometry.

    Science.gov (United States)

    Godin, Jean-Philippe; Hopfgartner, Gérard; Fay, Laurent

    2008-09-15

    The utility of liquid chromatography coupled to the isotope ratio mass spectrometry technique (LC-IRMS) has already been established through a variety of successful applications. However, the analytical constraint related to the use of aqueous mobile phases limits the LC separation mechanism. We report here a new strategy for high-precision (13)C isotopic analyses based on temperature-programmed LC-IRMS using aqueous mobile phases. Under these conditions, the isotopic precision and accuracy were studied. On one hand, experiments were carried out with phenolic acids using isothermal LC conditions at high temperature (170 degrees C); on the other hand, several experiments were performed by ramping the temperature, as conventionally used in a gas chromatography-based method with hydrosoluble fatty acids and pulses of CO 2 reference gas. In isothermal conditions at 170 degrees C, despite the increase of the CO 2 background, p-coumaric acid and its glucuronide conjugate gave reliable isotopic ratios compared to flow injection analysis-isotopic ratio mass spectrometry (FIA-IRMS) analyses (isotopic precision and accuracy are lower than 0.3 per thousand). On the opposite, for its sulfate conjugate, the isotopic accuracy is affected by its coelution with p-coumaric acid. Not surprisingly, this study also demonstrates that at high temperature (170 degrees C), a compound eluting with long residence time (i.e., ferulic acid) is degraded, affecting thus the delta (13)C (drift of 3 per thousand) and the peak area (compared to FIA-IRMS analysis at room temperature). Quantitation is also reported in isothermal conditions for p-coumaric acid in the range of 10-400 ng/mL and with benzoic acid as an internal standard. For temperature gradient LC-IRMS, in the area of the LC gradient (set up at 20 degrees C/min), the drift of the background observed produces a nonlinearity of SD (delta (13)C) approximately 0.01 per thousand/mV. To circumvent this drift, which impacts severely the

  19. Detection of argan oil adulteration with vegetable oils by high-performance liquid chromatography-evaporative light scattering detection.

    Science.gov (United States)

    Salghi, Rachid; Armbruster, Wolfgang; Schwack, Wolfgang

    2014-06-15

    Triacylglycerol profiles were selected as indicator of adulteration of argan oils to carry out a rapid screening of samples for the evaluation of authenticity. Triacylglycerols were separated by high-performance liquid chromatography-evaporative light scattering detection. Different peak area ratios were defined to sensitively detect adulteration of argan oil with vegetable oils such as sunflower, soy bean, and olive oil up to the level of 5%. Based on four reference argan oils, mean limits of detection and quantitation were calculated to approximately 0.4% and 1.3%, respectively. Additionally, 19 more argan oil reference samples were analysed by high-performance liquid chromatography-refractive index detection, resulting in highly comparative results. The overall strategy demonstrated a good applicability in practise, and hence a high potential to be transferred to routine laboratories.

  20. High pressure liquid chromatographic analysis of the main pungent principles of solar dried West Indian ginger (Zingiber officinale Roscoe)

    Energy Technology Data Exchange (ETDEWEB)

    Balladin, D.A.; Headley, O. [University of the West Indies, Cave Hill Campus, St. Michael, Barbados (West Indies). Centre for Resource Management and Environmental Studies; Chang-Yen, I. [University of the West Indies, St. Augustine Campus, Trinidad (West Indies). Faculty of Agriculture and Natural Sciences; McGaw, D.R. [University of the West Indies, St. Augustine Campus, Trinidad (West Indies). Dept. of Chemical Engineering

    1998-12-31

    The main pungent principles of West Indian ginger (Zingiber officinale Roscoe) were quantified and qualified using High Pressure Liquid Chromatography. This procedure was used to evaluate the pungency profile of fresh, solar dried and solar dried/steam distilled ginger rhizomes. In this investigation, the total oleoresin extracted was in the ratio [20: 1: 2] for [fresh ginger: solar dried: solar dried/steam distilled ginger rhizomes] with respect to the [6]-gingerol content. This simple isocratic HPLC method can be used to investigate the pungency profile of the extracted oleoresin from the ginger rhizomes. (author)

  1. Determination of cefoperazone concentration in serum and muscle tissue with a versatile high-pressure liquid chromatographic method.

    OpenAIRE

    Muder, R R; Diven, W. F.; Yu, V L; Johnson, J

    1982-01-01

    A rapid, specific, and reproducible high-pressure liquid chromatographic method was developed for the determination of cefoperazone concentration in serum and tissue. The assay uses a simple methanol extraction, with cefoxitin as the internal standard. The limits of detection are 1 to 150 micrograms/ml; the maximum coefficient of variation is 7.4%. Using the same chromatography column, muBondapak phenyl, and mobile-phase 0.005 M tetrabutylammonium buffer-acetonitrile (80:20), the method can b...

  2. Gelatin quantification by oxygen-18 labeling and liquid chromatography-high-resolution mass spectrometry.

    Science.gov (United States)

    Sha, Xiao-Mei; Tu, Zong-Cai; Wang, Hui; Huang, Tao; Duan, Deng-Le; He, Na; Li, De-Jun; Xiao, Hui

    2014-12-10

    Combined with high-performance liquid chromatography (HPLC) and linear-ion trap/Orbitrap high-resolution mass spectrometry, trypsin-catalyzed (16)O-to-(18)O exchange was used to establish an accurate quantitative method for bovine or porcine gelatin. The sophisticated modifications for these two mammalian gelatins were unambiguously identified by accurate mass and tandem mass spectrometry. Eighteen marker peptides were successfully identified for the bovine and porcine gelatin, respectively. The gelatins were subjected to (18)O or (16)O labeling in the presence of trypsin and mixed together in various ratios for quantification. All of the (18)O-labeled peptides were also confirmed by accurate mass and tandem mass spectrometry. The 10 marker peptides with the strongest signals were chosen to calculate the average ratios of (18)O-labeled and (16)O-labeled gelatin. The measured ratios of (18)O-labeled and (16)O-labeled peptides were very close to the mixing ratios of 20:1, 5:1, 1:1, and 1:5 with low standard deviation values. The samples with a mixing ratio of 1:1 (18)O-labeled and (16)O-labeled peptides were determined to 1.00 and 0.99 with standard deviations of 0.02 and 0.04 for bovine and porcine gelatins, respectively, indicating the high accuracy of this method. Trypsin-catalyzed (18)O labeling was proved to be an excellent internal calibrant for gelatins. When combined with HPLC and high-resolution mass spectrometry, it is an accurate and sensitive quantitative method for gelatin in the food industry. PMID:25404505

  3. Thermal elastic properties of liquid Fe-C at high pressure

    Science.gov (United States)

    Shimoyama, Y.; Terasaki, H. G.; Urakawa, S.; Takubo, Y.; Watanuki, T.; Katayama, Y.; Kondo, T.

    2015-12-01

    Planetary outer core contains some light elements and these elements affect thermo-elastic parameters of pure iron. The effect of light elements on density and bulk modulus of liquid iron is necessary for estimating of these core compositions. Sound velocity of liquid iron alloys is also important for identifying light elements in the core by comparison with observed seismic data. We have measured sound velocity and density of liquid Fe-C simultaneously at high pressure. High pressure experiments were performed using a DIA-type cubic anvil press (SMAP-180) at BL22XU beamline, SPring-8 synchrotron in Japan. Sound velocity (VP) was measured using pulse-echo overlapping method (Higo et al., 2009). Density (ρ) was measured using X-ray absorption method (Katayama et al., 1993). We measured velocity and density of liquid Fe-C between 1.1-5.8 GPa and 1480-1700 K. Obtained density and velocity of Fe-C was found to increase with pressure. This study shows the VP of liquid Fe-C decreased with increasing temperature. Previous study of liquid Fe-S shows little change with increasing temperature at all pressure conditions (Nishida et al., 2013, Jing et al., 2014). We fit the relationship between VP and pressure using Murnaghan's equation of state. We obtained KS0 = 102.5(1.2) GPa, K'S = 5.2(0.4) at 1700 K. Comparison of the present data with previous study, KS is similar to liquid Fe but liquid Fe-S is small. We compared the relation between density and sound velocity of liquid Fe-C. We have found that the behavior of liquid Fe-C is similar to that of liquid Fe in the Birch's plot. The effect of carbon on liquid Fe is small on Birch's plot.

  4. Determination of nucleosides in Cordyceps sinensis and Ganoderma lucidum by high performance liquid chromatography method

    Directory of Open Access Journals (Sweden)

    Masood Shah Khan

    2015-01-01

    Full Text Available Background: Nucleosides are supportive in the regulation and modulation of various physiological processes in body, they acts as precursors in nucleic acid synthesis, enhance immune response, help in absorption of iron and influence the metabolism of fatty acids. Cordyceps sinensis and Ganoderma lucidum are well-known for its use in traditional medicine of China, Nepal and India. They are rich in nucleosides such as adenine, adenosine, cordycepin, etc. Hence, a simple, economic and accurate high-performance liquid chromatography (HPLC analytical method was proposed for determination of adenine and adenosine for the quality control of plants. Materials and Methods: Chromatographic experiments were conducted on YL9100 HPLC system (South Korea. Reversed-phase chromatography was performed on a C18 column with methanol and dihydrogen phosphate as the mobile phase in isocratic elution method at a flow rate of 1.0 mL/min. Detection was carried out at 254 nm, which gives a sharp peak of adenine and adenosine at a retention time of 6.53 ± 0.02 min and 12.41 ± 0.02, respectively. Results and Discussion: Linear regression analysis data for the calibration plot showed a good linear relationship between response and concentration in the range of 25–200 µg/mL for adenosine and 100–800 µg/mL for adenine with regression coefficient of 0.999 and 0.996, respectively. The adenine was found 0.16% and 0.71% w/w in G. lucidum and in C. sinensis, respectively, and adenosine was found to be 0.14% w/w in G. lucidum whereas absent in C. sinensis. Conclusion: The developed HPLC method for the quantification of adenosine and adenine can be used for the quality control and standardization of crude drug and for the different herbal formulations, in which adenine and adenosine are present as major constituents. The wide linearity range, sensitivity, accuracy, and simple mobile phase imply the method is suitable for routine quantification of adenosine and adenine with

  5. Robust naphthyl methacrylate monolithic column for high performance liquid chromatography of a wide range of solutes.

    Science.gov (United States)

    Jonnada, Murthy; El Rassi, Ziad

    2015-08-28

    An organic monolithic column based on the co-polymerization of 2-naphthyl methacrylate (NAPM) as the functional monomer and trimethylolpropane trimethacrylate (TRIM) as the crosslinker was introduced for high performance reversed-phase liquid chromatography (RPC). The co-polymerization was performed in situ in a stainless steel column of 4.6mm i.d. in the presence of a ternary porogen consisting of 1-dodecanol and cyclohexanol. This monolithic column (referred to as naphthyl methacrylate monolithic column or NMM column) showed high mechanical stability at relatively high mobile phase flow velocity indicating that the column has excellent hydrodynamic characteristics. To characterize the NMM column, different probe molecules including alkyl benzenes, and aniline, benzene, toluene and phenol derivatives were chromatographed on the column and the results in terms of k, selectivity and plate counts were compared to those obtained on an octadecyl silica (ODS) column in order to assess the presence of π-π and hydrophobic interactions on the NMM column under otherwise the same elution conditions. The NMM column offered additional π-π interactions with aromatic molecules in addition to hydrophobic interactions under RPC elution conditions. Run-to-run and column-to-column reproducibility of solute k values were evaluated, and percent relative standard deviation of column using shallow (30min at 1.0mL/min), steep (10min at 1.0mL/min) and ultra steep (1min at 3.0mL/min) linear gradient elution at increasing ACN concentration in the mobile phase using a 10cm×4.6mm i.d. column in case of shallow and steep linear gradients and a 3cm×4.6mm i.d. column for ultra steep linear gradient.

  6. Chiral stationary phases based on chitosan bis(methylphenylcarbamate)-(isobutyrylamide) for high-performance liquid chromatography.

    Science.gov (United States)

    Tang, Sheng; Bin, Qin; Chen, Wei; Bai, Zheng-Wu; Huang, Shao-Hua

    2016-04-01

    A series of chitosan bis(methylphenylcarbamate)-(isobutyrylamide) derivatives were synthesized by carbamylating chitosan isobutyrylamide with different methylphenyl isocyanates. Then the prepared chitosan derivatives were coated onto 3-aminopropyl silica particles, resulting in a series of new chiral stationary phases (CSPs) for high-performance liquid chromatography. It was observed that the chiral recognition abilities of these coated-type CSPs depended very much on the substituents on the phenyl moieties of the chitosan derivatives, the eluent composition, as well as the structure of racemates. As a typical example, the eluent tolerance of the prepared CSP with the best enantioseparation ability was investigated in detail, and the results revealed that the CSP exhibited extraordinary solvent tolerance and could still work without significant loss in enantioseparation capability after being flushed with chloroform (100%), ethyl acetate (100%) and even THF/n-hexane (70/30, v/v), while the traditional coated-type CSPs based on the cellulose and amylose derivatives, such as cellulose tris(3,5-dimethylphenylcarbamate) (CDMPC) and amylose tris(3,5-dimethylphenylcarbamate) (ADMPC), might be dissolved or highly swollen in these eluents. Therefore, the application of the resultant CSPs could address the problem of the dissolution and high swelling of traditional coated-type CSPs in some unusual eluents, broadening the possibility of eluent choice. In addition, a comparison of the prepared CSPs with the well known CDMPC- and ADMPC- based CSPs concerning the chiral recognition ability was also made. Separation performances achieved on the as-prepared CSPs in different eluents were found to be even superior to CDMPC- and ADMPC-based CSPs for the tested chiral compounds. In summary, we could safely draw the conclusion that the CSPs derived from chitosan isobutyrylamide derivatives were capable of excellent chiral recognition ability, and meanwhile possessed satisfactory

  7. [Isolation of chemical constituents from Ziziphora clinopodioides Lam. with recycling preparative high performance liquid chromatography].

    Science.gov (United States)

    Li, Guozhu; Meng, Qingyan; Luo, Bi; Ge, Zhenghong; Liu, Wenjie

    2015-01-01

    The combination of alternate recycling and direct recycling preparative liquid chromatography method was developed for the isolation of chemical constituents from Ziziphora clinopodioides Lam. The crude extract was obtained from Ziziphora clinopodioides Lam. by solvent extraction, column chromatography and reversed-phase (RP) flash chromatography. All the separations were performed with methanol and water as mobile phases and the developed recycling preparative method was used with twin RP columns switched by a two-position ten-way valve for the separation. The mobile phase was recycled in close loop with a two-position six-way valve. The fraction I and fraction II from reversed-phase flash chromatography were selected for the demonstration of separation power of the proposed protocol, and five compounds were obtained from Ziziphora clinopodioides Lam. The isolated five compounds were identified as pinocembrin-7-O-rutinoside, pinocembrin-7-O-rutinoside, acacetin-7-O-rutinoside, picein and protocatechuic acid with nuclear magnetic resonance (NMR). The experimental results showed that the developed preparation method exhibited higher separation efficiency with less mobile phase used than the reported methods, and could be expected as an effective method for the separation of complex natural products, especially the compounds with similar structures. PMID:25958674

  8. Highly sensitive quantification of pyrethroid insecticide etofenprox in vegetables with high-performance liquid chromatography and fluorescence detection.

    Science.gov (United States)

    Watanabe, Eiki; Baba, Koji

    2015-03-13

    This paper describes a highly sensitive analytical method using high-performance liquid chromatography and fluorescence detection (HPLC-FLD) capable of quantifying trace amounts of synthetic pyrethroid insecticide etofenprox residue in six vegetable samples: bell pepper, cucumber, eggplant, Japanese mustard spinach, spinach, and tomato. After extraction with acetonitrile, the crude sample extract was cleaned up with a solid-phase extraction cartridge. The matrix interference derived from the tested vegetable samples was evaluated. Quantification was conducted using external calibrators prepared in pure acetonitrile. The limits of quantification for etofenprox in each sample were 1.87-3.87 ng/g. Recoveries obtained by application of the proposed analytical method of vegetable samples spiked at the considerably low levels (5-100 ng/g) were 85-111% with relative standard deviations of less than 12%. The proposed method using the HPLC-FLD was applied for trace analysis of the insecticide residue in vegetable samples. PMID:25662063

  9. Determination of Bisphenol A and Bisphenol AF in Vinegar samples by two-component mixed ionic liquid dispersive liquid-phase microextraction coupled with high performance liquid chromatography

    International Nuclear Information System (INIS)

    This paper describes a sensitive and simple method for the determination of bisphenol A (BPA) and bisphenol AF (BPAF) in vinegar samples using two-component mixed ionic liquid dispersive liquid-phase microextraction coupled with high performance liquid chromatography. In this work, BPA and BPAF were selected as the model analytes, and two-component mixed ionic liquid included 1-butyl-3-methylimidazolium hexafluorophosphate ((C4Mim)PF6) and 1-hexyl-3-methyl-imidazolium hexafluorophosphate ((C6Mim)PF6) was used as the extraction solvent for the first time here. Parameters that affect the extraction efficiency were investigated. Under the optimum conditions, good linear relationships were discovered in the range of 1.0-100 micro g/L for BPA and 2.0-150 micro g/L for BPAF, respectively. Detection limits of proposed method based on the signal-to-noise ratio (S/N=3) were in the range of 0.15-0.38 micro g/L. The efficiencies of proposed method have also been demonstrated with spiked real vinegar samples. The result show this method/ procedure to be a more efficient approach for the determination of BPA and BPAF in real vinegar, presenting average recovery rate of 89.3-112 % and precision values of 0.9-13.5% (RSDs, n = 6). In comparison with traditional solid phase extraction procedures this method results in lower solvent consumption, low pollution levels, and faster sample preparation. (author)

  10. The MAREDAT global database of high performance liquid chromatography marine pigment measurements

    Directory of Open Access Journals (Sweden)

    J. Peloquin

    2012-12-01

    Full Text Available A global pigment database consisting of 37 103 pigment suites measured by high performance liquid chromatography was assembled in support of the MARine Ecosytem DATa (MAREDAT initiative. These data originate from 136 field surveys within the global ocean, were solicited from investigators and databases, compiled, and then quality controlled. Nearly one quarter of the data originates from the Laboratoire d'Océanographie de Villefranche (LOV, with an additional 20% and 17% stemming from the US JGOFS and LTER programs, respectively. The MAREDAT pigment database provides high quality measurements of the major taxonomic pigments including chlorophyll a and b, 19'butanoyloxyfucoxanthin, 19'hexanoyloxyfucoxanthin, alloxanthin, divinyl chlorophyll a, fucoxanthin, lutein, peridinin, prasinoxanthin, violaxanthin and zeaxanthin, which may be used in varying combinations to estimate phytoplankton community composition. Quality control measures consisted of flagging samples that had a total chlorophyll a concentration of zero, had fewer than four reported accessory pigments, or exceeded two standard deviations of the log-linear regression of total chlorophyll a with total accessory pigment concentrations. We anticipate the MAREDAT pigment database to be of use in the marine ecology, remote sensing and ecological modeling communities where it will support model validation and advance our global perspective on marine biodiversity. The original dataset together with quality control flags as well as the gridded MAREDAT pigment data may be downloaded from PANGAEA: doi:10.1594/PANGAEA.793246.

  11. Analysis of 99mTc-labeled radiopharmaceuticals by high-performance liquid chromatography

    International Nuclear Information System (INIS)

    High-performance liquid chromatography (HPLC) equiped with on line radiometric and optical detectors (i.e. radio-HPLC) have been applied to the radiochemical analysis of commonly-used 99mTc-radio pharma ceuticals with a view point to check the radiochemical purities of the compounds. Chromatographic conditions were determined by examination of the types of column, mobile phase and pH. An aqueous size-exclusion (Shim-pack Diol-300) and reversed-phase column (Zorbax-ODS) were found to be suitable for 99mTc-HSA and the other 99mTc-agents, respectively. The analysis of low molecular weight 99mTc-agents (e.g. 99mTc-DTPA, 99mTc-DMSA, 99mTc-pyrophosphate, 99mTc-phytic acid, 99mTc-MDS, 99mTc-HMDP) were done by reversed-phaseion pairing chromatography using a optimized mobile phase consisted on a mixture of 50 mM phosphate buffer (pH 7.0) and 2 mM TBA (tetra nbutyl) ammonium hydroxide) in 30 % methanol. The mobile phases for analysis of medium molecular weight 99mTc-HSA were consisted of a mixture of 50 mM phosphate buffer (ph 7.0) in 30 % methanol, and a mixtures of 1 % SDS (sodium dodecyl sulfonate) in Tris buffer (pH. 7.0), respectively. It was apparent from the radio-chromatograms obtained from these chromatographic conditions, that impurity of 99mTcO4 was observed in 99mTc-pyrophosphate, 99mTc-phytic acid, 99mTc-MDP, 99mTc-HMDP, and impurities of 99mTc-labeled species and 99mTcO4, were observed in 99mTc-HIDA, 99mTc-HIDA, 99mTc-HSA. The radiochemical impurities of the 99mTc-radiopharmaceuticals were ranged between 90 and 100 %. From these results, radio-HPLC has been shown to be suitable method for analysis of 99mTc-radiopharmaceuticals, with rapidity and excellent precision. (author)

  12. Comparative analysis of steroidal saponins in four Dioscoreae herbs by high performance liquid chromatography coupled with mass spectrometry.

    Science.gov (United States)

    Guo, Long; Zeng, Su-Ling; Zhang, Yu; Li, Ping; Liu, E-Hu

    2016-01-01

    Steroidal saponins, which exhibit multiple pharmacological effects, are the major bioactive constituents in herbal medicines from Dioscoreae species. In this study, a sensitive method based on high performance liquid chromatography-mass spectrometry (HPLC-MS) was established and validated for qualitative and quantitative analysis of steroidal saponins in four Dioscoreae herbs including Dioscoreae Nipponica Rhizome (DNR) and Dioscoreae Hypoglaucae Rhizome (DHR), Dioscoreae Spongiosae Rhizome (DSR) and Dioscoreae Rhizome (DR). A total of eleven steroidal saponins were identified by high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC-QTOF/MS). Furthermore, seven major steroidal saponins was simultaneous quantified using a high performance liquid chromatography coupled with triple quadrupole mass spectrometry (HPLC-QQQ/MS). The qualitative and quantitative analysis results indicated that the chemical composition of DNR, DHR and DSR samples exhibited a high level of global similarity, while the ingredients in DR varied greatly from the other three herbs. Moreover, principal component analysis (PCA) and hierarchical clustering analysis (HCA) were performed to compare and discriminate the Dioscoreae herbs based on the quantitative data. The results demonstrated the qualitative and quantitative analysis of steroidal saponins based on HPLC-MS is a feasible method for quality control of Dioscoreae herbs.

  13. Elucidation and identification of amino acid containing membrane lipids using liquid chromatography/high-resolution mass spectrometry

    OpenAIRE

    Moore, E.K.; Hopmans, E.C.; Rijpstra, W.I.C.; Villanueva, L; Sinninghe Damste, J. S.

    2016-01-01

    RATIONALE: Intact polar lipids (IPLs) are the building blocks of cell membranes, and amino acid containing IPLs havebeen observed to be involved in response to changing environmental conditions in various species of bacteri a. High-performance liquid chromatography/mass spectrometry (HPLC/MS) has become the primary method for analysis ofIPLs. Many glycerol-free amino acid containing membrane lipids (AA-IPLs), which are structurally different thanabundant aminophospholipids, have not been char...

  14. Application of Denaturing High-Performance Liquid Chromatography for Monitoring Sulfate-Reducing Bacteria in Oil Fields

    OpenAIRE

    Priha, Outi; Nyyssönen, Mari; Bomberg, Malin; Laitila, Arja; Simell, Jaakko; Kapanen, Anu; Juvonen, Riikka

    2013-01-01

    Sulfate-reducing bacteria (SRB) participate in microbially induced corrosion (MIC) of equipment and H2S-driven reservoir souring in oil field sites. Successful management of industrial processes requires methods that allow robust monitoring of microbial communities. This study investigated the applicability of denaturing high-performance liquid chromatography (DHPLC) targeting the dissimilatory sulfite reductase ß-subunit (dsrB) gene for monitoring SRB communities in oil field samples from th...

  15. Simultaneous determination of 20 food additives by high performance liquid chromatography with photo-diode array detector

    Institute of Scientific and Technical Information of China (English)

    Kang Ma; Ya Nan Yang; Xiao Xiong Jiang; Min Zhao; Ye Qiang Cai

    2012-01-01

    An efficient and accurate analytical method was developed for the simultaneous determination of 20 synthetic food additives,including three sweeteners,seven food colorants,nine synthetic preservatives and caffeine,by high performance liquid chromatography (HPLC) with photodiode array detector (PDA).This method permits the detection of food additives at very low concentrations (0.005-0.150 μg/mL).The applicability was verified by the determination of food additives present in various foodstuffs.

  16. A high performance liquid chromatography with ultraviolet method for Eschweilera nana leaves and their anti-inflammatory and antioxidant activities

    OpenAIRE

    Priscila M. Outuki; Lazzeri, Nides S.; Lizziane M. B. de Francisco; Ciomar A. Bersani Amado; Ferreira, Izabel C. P.; Mara Lane C. Cardoso

    2015-01-01

    Background: Eschweilera nana Miers is a tree widely distributed in Cerrado, Brazil. Objective: In this study, we aimed to describe its phytochemical properties and antioxidant and topical anti inflammatory effects for the first time, as well validate an high performance liquid chromatography with ultraviolet/visible (HPLC UV Vis) method for the separation and quantification of the main components (hyperoside and rutin) in the hydroalcoholic extract of E. nana leaves. Materials and Methods: St...

  17. Protective properties of wine products and the role of high performance liquid chromatography in the study of these properties

    International Nuclear Information System (INIS)

    Data on the biologically active substances present in wines and wine products, the methods of their determination, and changes under chemical, radiation and other types of action are generalized. The role of high performance liquid chromatography in the studies of the protective properties of wines is demonstrated. Particular attention is devoted to problems of counterfeiting of wine products and the possibility to reveal it by using amperometric determination of the antioxidant activity. The bibliography includes 117 references

  18. Enantiomeric high-performance liquid chromatography resolution and absolute configuration of 6β-benzoyloxy-3α-tropanol.

    Science.gov (United States)

    Muñoz, Marcelo A; González, Natalia; Joseph-Nathan, Pedro

    2016-07-01

    The absolute configuration of the naturally occurring isomers of 6β-benzoyloxy-3α-tropanol (1) has been established by the combined use of chiral high-performance liquid chromatography with electronic circular dichroism detection and optical rotation detection. For this purpose (±)-1, prepared in two steps from racemic 6-hydroxytropinone (4), was subjected to chiral high-performance liquid chromatography with electronic circular dichroism and optical rotation detection allowing the online measurement of both chiroptical properties for each enantiomer, which in turn were compared with the corresponding values obtained from density functional theory calculations. In an independent approach, preparative high-performance liquid chromatography separation using an automatic fraction collector, yielded an enantiopure sample of OR (+)-1 whose vibrational circular dichroism spectrum allowed its absolute configuration assignment when the bands in the 1100-950 cm(-1) region were compared with those of the enantiomers of esters derived from 3α,6β-tropanediol. In addition, an enantiomerically enriched sample of 4, instead of OR (±)-4, was used for the same transformation sequence, whose high-performance liquid chromatography follow-up allowed their spectroscopic correlation. All evidences lead to the OR (+)-(1S,3R,5S,6R) and OR (-)-(1R,3S,5R,6S) absolute configurations, from where it follows that samples of 1 isolated from Knightia strobilina and Erythroxylum zambesiacum have the OR (+)-(1S,3R,5S,6R) absolute configuration, while the sample obtained from E. rotundifolium has the OR (-)-(1R,3S,5R,6S) absolute configuration.

  19. Use of high-performance liquid chromatography to monitor stability of tetracycline and chlortetracycline in susceptibility determinations.

    OpenAIRE

    A. Ray; Newton, V

    1991-01-01

    Trypticase soy broth and nutrient broth were used in the antimicrobial susceptibility testing of tetracycline and chlortetracycline with Bacillus subtilis. The stability of the antibiotics in both media at an incubation temperature of 37 degrees C was monitored by high-performance liquid chromatography. It was found that Trypticase soy broth has limited application in susceptibility testing for the tetracycline congeners tested and that chlortetracycline is more unstable than tetracycline.

  20. Determination of Pharmacologically Active Compounds in Root Extracts of Cassia alata L. by use of High Performance Liquid Chromatography

    OpenAIRE

    Fernand, Vivian E.; Dinh, David T.; Washington, Samuel J.; FAKAYODE, SAYO O.; Losso, Jack N.; van Ravenswaay, Rick O.; Warner, Isiah M.

    2007-01-01

    A simple high performance liquid chromatography (HPLC) method was developed and validated for the determination of six phenolic compounds, five anthraquinones (rhein, aloe-emodin, emodin, chrysophanol and physcion) and a flavonoid (kaempferol), in root extracts from Cassia alata L. Solid-phase extraction, using C18 cartridges, was used to remove interfering substances from the root extracts. The extracts were analyzed on a C18 column using an isocratic mobile phase which consisted of acetonit...

  1. Determination of Sudan Residues in Sausage by Matrix Solid-Phase Dispersion and High-Performance Liquid Chromatography.

    Science.gov (United States)

    Zhai, Yujuan; Cheng, Jianhua

    2015-09-01

    A method based on matrix solid-phase dispersion and high-performance liquid chromatography was applied to the determination of four Sudan red residues in sausage. The proposed method required only 0.5 g sample. The neutral alumina was used as the dispersant sorbent while n-hexane containing 10% (v/v) acetone was used as the eluting solvent. The recoveries in samples ranged from 76.4 to 111.0% and relative standard deviations were sausage.

  2. Simultaneous determination of 11 bioactive compounds in Jaeumganghwa-tang by high performance liquid chromatography-diode array detection

    OpenAIRE

    Bo-Ra Yun; Jin Bae Weon; Jiwoo Lee; Min Rye Eom; Choong Je Ma

    2014-01-01

    Background: Jaeumganghwa-tang (JEGH) is a traditional Korean herbal medicine for the treatment of chronic bronchitis, nephritis and diabetes mellitus. Objective: A high performance liquid chromatography-diode array detector (HPLC-DAD) method was developed for simultaneous determination of 11 major compounds such as 5- hydroxymethylfurfural, mangiferin, paeoniflorin, nodakenin, naringin, hesperidin, decursinol, berberine, glycyrrhizin, atractylenolide III and decursin, in JEGH. Materials and M...

  3. Isolation of lignans glycosides from Alibertia sessilis (Vell.) K. Schum. (Rubiaceae) by preparative high-performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Silva, V.C. da; Bolzani, V. da S.; Lopes, M.N. [UNESP, Araraquara, SP (Brazil). Inst. de Quimica. Dept. de Quimica Organica; Silva, G.H. [Universidade Federal de Sergipe, Aracaju, SE (Brazil). Dept. de Quimica]. E-mail: mnlopes@iq.unesp.br

    2006-10-15

    Enantiomeric aglycone lignans contained in a mixture were separated from a fraction of the extract of the stems of Alibertia sessilis (Vell.) K. Schum. (Rubiaceae) by preparative high-performance liquid chromatography. An efficient and fast separation can be achieved with methanol-water (30:70, v/v). Their structures were identified as (+)-lyoniresinol 3{alpha}-O-{beta}-glucopyranoside and (-)-lyoniresinol 3{alpha}-O-{beta}-glucopyranoside, being reported for the first time in Rubiaceae. (author)

  4. Post Column Derivatization Using Reaction Flow High Performance Liquid Chromatography Columns.

    Science.gov (United States)

    Jones, Andrew; Pravadali-Cekic, Sercan; Hua, Stanley; Kocic, Danijela; Camenzuli, Michelle; Dennis, Gary; Shalliker, Andrew

    2016-04-26

    A protocol for the use of reaction flow high performance liquid chromatography columns for methods employing post column derivatization (PCD) is presented. A major difficulty in adapting PCD to modern HPLC systems and columns is the need for large volume reaction coils that enable reagent mixing and then the derivatization reaction to take place. This large post column dead volume leads to band broadening, which results in a loss of observed separation efficiency and indeed detection in sensitivity. In reaction flow post column derivatization (RF-PCD) the derivatization reagent(s) are pumped against the flow of mobile phase into either one or two of the outer ports of the reaction flow column where it is mixed with column effluent inside a frit housed within the column end fitting. This technique allows for more efficient mixing of the column effluent and derivatization reagent(s) meaning that the volume of the reaction loops can be minimized or even eliminated altogether. It has been found that RF-PCD methods perform better than conventional PCD methods in terms of observed separation efficiency and signal to noise ratio. A further advantage of RF-PCD techniques is the ability to monitor effluent coming from the central port in its underivatized state. RF-PCD has currently been trialed on a relatively small range of post column reactions, however, there is currently no reason to suggest that RF-PCD could not be adapted to any existing one or two component (as long as both reagents are added at the same time) post column derivatization reaction.

  5. Radiotracer properties determined by high performance liquid chromatography: a potential tool for brain radiotracer discovery

    International Nuclear Information System (INIS)

    Introduction: Previously, development of novel brain radiotracers has largely relied on simple screening tools. Improved selection methods at the early stages of radiotracer discovery and an increased understanding of the relationships between in vitro physicochemical and in vivo radiotracer properties are needed. We investigated if high performance liquid chromatography (HPLC) methodologies could provide criteria for lead candidate selection by comparing HPLC measurements with radiotracer properties in humans. Methods: Ten molecules, previously used as radiotracers in humans, were analysed to obtain the following measures: partition coefficient (Log P); permeability (Pm); percentage of plasma protein binding (%PPB); and membrane partition coefficient (Km). Relationships between brain entry measurements (Log P, Pm and %PPB) and in vivo brain percentage injected dose (%ID); and Km and specific binding in vivo (BPND) were investigated. Log P values obtained using in silico packages and flask methods were compared with Log P values obtained using HPLC. Results: The modelled associations with %ID were stronger for %PPB (r2=0.65) and Pm (r2=0.77) than for Log P (r2=0.47) while 86% of BPND variance was explained by Km. Log P values were variable dependant on the methodology used. Conclusions: Log P should not be relied upon as a predictor of blood-brain barrier penetration during brain radiotracer discovery. HPLC measurements of permeability, %PPB and membrane interactions may be potentially useful in predicting in vivo performance and hence allow evaluation and ranking of compound libraries for the selection of lead radiotracer candidates at early stages of radiotracer discovery.

  6. Characterization of Fumonisin A-Series by High-Resolution Liquid Chromatography-Orbitrap Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Masayoshi Tamura

    2014-08-01

    Full Text Available Fumonisin A-series (FAs in a reference material of corn sample that was naturally contaminated with fumonisins was characterized using high-resolution liquid chromatography-Orbitrap mass spectrometry (LC-Orbitap MS. Peaks for fumonisin B1 (FB1, fumonisin B2 (FB2, and fumonisin B3 (FB3, in addition to three peaks corresponding to unknown compounds I, II, and III, were detected in the chromatogram for the corn sample. Fragment ion analysis for FB1, FB2, and FB3 showed that while the ions formed at m/z values of 200–800 were similar to those formed by the cleavage of the tricarballylic acids and the hydroxyl groups, the fragmentation patterns at m/z values of 50–200 varied depending on the hydroxyl group locations in the compounds. Fragment ion analysis of compounds I–III revealed structural similarities to FBs, only differing by an additional C2H2O in the unknown compounds. Using these results and by comparing the product ion mass spectra of compound I with fumonisin A1 (FA1 synthesized from FB1 standards, compounds I–III were hypothesized to be N-acetyl analogs of FBs: fumonisins A1 (FA1, A2 (FA2, and A3 (FA3. The method for determining concentrations was validated with FA1, FB1, FB2, and FB3 standards and applied to analyze the reference material. The FB1, FB2, and FB3 analytical levels were within acceptance limits and the amount of FA1 in the material was ~15% of FB1 amount at 4.2 mg/kg.

  7. Analysis of Organic Acids in Blueberry Juice and its Fermented Wine by High Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Hongxue Fu

    2015-08-01

    Full Text Available A rapid analytical method for simultaneous separation and determination of organic acids is of the essence for quality control of blueberry juice and its fermented wine. In this present study, a High Performance Liquid Chromatography (HPLC method for separation and determination of organic acids (oxalic acid, gluconic acid, tartaric acid, formic acid, pyruvic acid, malic acid, isocitric acid, shikimic acid, lactic acid, acetic acid, citric acid, succinic acid and propionic acid in blueberry juice and wine has been developed. The chromatographic separation was performed at 35°C by using an ammonium hydrogen phosphate buffer (pH 2.8 as mobile phase and 0.6 mL/min as the column flow rate. A C18 analytical column and Ultraviolet Detection (UV at &lembda = 210 nm were used for all acids above. The method was validated for linearity, limit of detection, limit of quantification, accuracy and precision. The applicability of the method was demonstrated by analyzing organic acids in real samples of six species of blueberry juices and wines. The results show that species significantly affect distribution of organic acids in samples but not the kinds of organic acids between six species. Oxalic acid, gluconic acid, malic acid, shikimic acid and citric acid are detected in blueberry juice. Citric acid, which accounts for a percentage >75% of the whole content of organic acids, is the major acid in four kinds of tested species (Sharpblue, Misty, Anna and Bluecrop. In the other two species (Britewell and Premier, malic acid, gluconic acid and citric acid own a mean percentage of 40, 32 and 25%, respectively. After yeast fermentation and aging, several new organic acids (pyruvic acid, isocitric acid, lactic acid, acetic acid, succinic acid and propionic acid appear in wine.

  8. [Determination of protocatechuic acid in rat plasma by high performance liquid chromatography].

    Science.gov (United States)

    Han, Ying; Xiong, Zhili; Yang, Chunjuan; Liu, Man; Li, Famei

    2007-03-01

    A method was developed for the quantitative determination of protocatechuic acid in rat plasma by high performance liquid chromatography (HPLC). With added p-hydroxybenzoic acid as internal standard, the plasma samples were extracted with a solvent mixture of methanol and acetonitrile ( 1: 5, v/v). The analyte was determined by HPLC with a Diamondsil C18 column and a mobile phase of acetonitrile-water (adjusted to pH 2.5 with H3PO4, 9: 91, v/v) at a flow rate of 1. 2 mL/min. The UV detection wavelength was 260 nm. The assay exhibited a good linearity in the concentration range from 0. 050 to 3. 20 mg/L with a correlation coefficient of 0. 997 8. The limit of quantification was 0. 050 mg/L. The relative standard deviations of intra-day and inter-day determination were both less than 7. 0% and the accuracy ranged from - 1. 4% to 2. 6%. The extraction recoveries of protocatechuic acid from rat plasma samples at three concentration levels were 83. 4%, 87. 3%, and 91. 1%, respectively. The developed method was applied to a pharmacokinetic study. The main pharmacokinetic parameters in rats after a single oral dose of 10 mL/kg body weight were as follows: Cmax of (3. 16 +0. 03) microg/mL, tmax of (0. 50 +/- 0. 00) h, AU0-->t of (39. 9 +/- 5. 9) microg x mL(-1) x h, AUC-->infinity of (54. 8 +/- 8. 1) microg x mL(-1) x h and t1/2 of (3. 87 +/- 0. 25) h. The method was proved to be simple, sensitive and accurate, thus suitable for the pharmacokinetic study of protocatechuic acid in rat plasma. PMID:17580687

  9. Post Column Derivatization Using Reaction Flow High Performance Liquid Chromatography Columns.

    Science.gov (United States)

    Jones, Andrew; Pravadali-Cekic, Sercan; Hua, Stanley; Kocic, Danijela; Camenzuli, Michelle; Dennis, Gary; Shalliker, Andrew

    2016-01-01

    A protocol for the use of reaction flow high performance liquid chromatography columns for methods employing post column derivatization (PCD) is presented. A major difficulty in adapting PCD to modern HPLC systems and columns is the need for large volume reaction coils that enable reagent mixing and then the derivatization reaction to take place. This large post column dead volume leads to band broadening, which results in a loss of observed separation efficiency and indeed detection in sensitivity. In reaction flow post column derivatization (RF-PCD) the derivatization reagent(s) are pumped against the flow of mobile phase into either one or two of the outer ports of the reaction flow column where it is mixed with column effluent inside a frit housed within the column end fitting. This technique allows for more efficient mixing of the column effluent and derivatization reagent(s) meaning that the volume of the reaction loops can be minimized or even eliminated altogether. It has been found that RF-PCD methods perform better than conventional PCD methods in terms of observed separation efficiency and signal to noise ratio. A further advantage of RF-PCD techniques is the ability to monitor effluent coming from the central port in its underivatized state. RF-PCD has currently been trialed on a relatively small range of post column reactions, however, there is currently no reason to suggest that RF-PCD could not be adapted to any existing one or two component (as long as both reagents are added at the same time) post column derivatization reaction. PMID:27168419

  10. Enantiomeric Separations of Pyriproxyfen and its Six Chiral Metabolites by High-Performance Liquid Chromatography.

    Science.gov (United States)

    Zhang, Chuntao; Liu, Hui; Liu, Donghui; Wang, Liying; Gao, Jing; Zhou, Zhiqiang; Wang, Peng

    2016-03-01

    Pyriproxyfen is a chiral insecticide, and over 10 metabolites have been identified in the environment. In this work the separations of the enantiomers of pyriproxyfen and its six chiral metabolites were studied by high-performance liquid chromatography (HPLC). Both normal phase and reverse phase were applied using the chiral columns Chiralpak IA, Chiralpak IB, Chiralpak IC, Chiralcel OD, Chiralcel OD-RH, Chiralpak AY-H, Chiralpak AD-H, Chiracel OJ-H, (R,R)-Whelk-O 1, and Lux Cellulose-3. The effects of the chromatographic parameters such as mobile phase composition and temperature on the separations were investigated and the enantiomers were identified with an optical rotation detector. The enantiomers of these targets could obtain complete separations (resolution factor Rs > 1.5) on Chiralpak IA, Chiralpak IB, Chiralcel OD, Chiralpak AY-H, or Chiracel OJ-H under normal conditions. Chiralcel OJ-H showed the best chiral separation results with n-hexane as mobile phase and isopropanol (IPA) as modifier. The simultaneous enantiomeric separation of pyriproxyfen and four chiral metabolites was achieved on Chiralcel OJ-H under optimized condition: n-hexane/isopropanol = 80/20, 15°C, flow rate of 0.8 ml/min, and UV detection at 230 nm. The enantiomers of pyriproxyfen and the metabolites , , and obtained complete separations on Chiralpak IA, Chiralpak IC, and Lux Cellulose-3 under reverse phase using acetonitrile/water as the mobile phase. The retention factors (k) and selectivity factors (α) decreased with increasing temperature, and the separations were better under low temperature in most cases. The work is of significance for the investigation of the environmental behaviors of pyriproxyfen on an enantiomeric level.

  11. [Determination of aflatoxins in cashew by high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Bi, Ruifeng; Fan, Zhixian; Fu, Meng

    2011-12-01

    A method for the determination of four aflatoxins in cashew using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed. The sample was extracted with methanol-water (8: 2, v/v) solution, followed by a cleanup procedure with Florisil column. The target compounds were eluted using 5 mL acetone-water-formic acid (96: 3.5:0.5, v/v/v) solution. The eluate was dried under N2, then dissolved in 1 mL methanol. Four aflatoxins were separated in MG C18 column (100 mm x 3.0 mm, 3 microm) adopting a gradient program within 15 min. A triple quadrupole mass spectrometry equipped with an electrospray ionization source operated in the positive ion mode was used to detect the aflatoxins. The good correlation coefficients (r2 > 0.997) of the four aflatoxins were obtained within their respective linear ranges. The limits of detection (S/N = 3) were between 0.009 microg/kg and 0.04 microg/kg, and the limits of quantification (S/N = 10) were between 0.03 microg/kg and 0.12 microg/kg. The recoveries were in a range of 63.0% -78.5% with the relative standard deviations (RSDs) varied from 2.8% to 9.1%. The validation results meet the requirements of trace assay. Matrix effects were estimated and the signal suppression/enhancement ranged from 88.8% to 99.4%. The results indicate that the developed method is simple, fast, accurate, and can be applied for the determination of fours aflatoxins in cashew.

  12. Simultaneous determination of multiple marker constituents in concentrated Gegen Tang granule by high performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Yip Yuekeung

    2007-06-01

    Full Text Available Abstract Background Concentrated Gegen Tang (GT granule is a widely available traditional Chinese medicinal product for the treatment of cold and flu. There was no reliable analytical method available for the quality assessment of GT granules. Methods An HPLC method with an Agilent Zorbax SB-Phenyl Stablebond column (250 × 4.6 mm, 5 μm was developed and validated. The mobile phase gradient was a mixture of 0.1% trifluoroacetic acid (TFA in acetonitrile (ACN and 0.1% TFA in water. The detection with a diode-array detector was set at 207, 230, 250 and 275 nm. Seven components, namely puerarin, daidzein, paeoniflorin, cinnamic acid, glycyrrhizin, ephedrine and pseudoephedrine were selected as marker compounds for the evaluation. Results The regression equations revealed good linear relationships (correlation coefficients: 0.9994–0.9998 between the peak areas and concentrations. The recovery was between 98.8% and 101.7% with good precision and accuracy. The quality of GT granule from four different manufacturers was evaluated with this newly developed method. Samples from four manufacturers showed similar profiles but contents of the detected markers varied significantly among manufacturers and batches. Conclusion A new method using high performance liquid chromatography (HPLC has been developed for simple and reliable quality control of commercial concentrated GT granules. Sensitivity was increased by multi-wavelength detection. The contents of selected marker components in GT granules varied significantly among manufacturers and batches, making it necessary to evaluate the quality of concentrated GT granules in the market.

  13. Enantiomeric Separations of Pyriproxyfen and its Six Chiral Metabolites by High-Performance Liquid Chromatography.

    Science.gov (United States)

    Zhang, Chuntao; Liu, Hui; Liu, Donghui; Wang, Liying; Gao, Jing; Zhou, Zhiqiang; Wang, Peng

    2016-03-01

    Pyriproxyfen is a chiral insecticide, and over 10 metabolites have been identified in the environment. In this work the separations of the enantiomers of pyriproxyfen and its six chiral metabolites were studied by high-performance liquid chromatography (HPLC). Both normal phase and reverse phase were applied using the chiral columns Chiralpak IA, Chiralpak IB, Chiralpak IC, Chiralcel OD, Chiralcel OD-RH, Chiralpak AY-H, Chiralpak AD-H, Chiracel OJ-H, (R,R)-Whelk-O 1, and Lux Cellulose-3. The effects of the chromatographic parameters such as mobile phase composition and temperature on the separations were investigated and the enantiomers were identified with an optical rotation detector. The enantiomers of these targets could obtain complete separations (resolution factor Rs > 1.5) on Chiralpak IA, Chiralpak IB, Chiralcel OD, Chiralpak AY-H, or Chiracel OJ-H under normal conditions. Chiralcel OJ-H showed the best chiral separation results with n-hexane as mobile phase and isopropanol (IPA) as modifier. The simultaneous enantiomeric separation of pyriproxyfen and four chiral metabolites was achieved on Chiralcel OJ-H under optimized condition: n-hexane/isopropanol = 80/20, 15°C, flow rate of 0.8 ml/min, and UV detection at 230 nm. The enantiomers of pyriproxyfen and the metabolites , , and obtained complete separations on Chiralpak IA, Chiralpak IC, and Lux Cellulose-3 under reverse phase using acetonitrile/water as the mobile phase. The retention factors (k) and selectivity factors (α) decreased with increasing temperature, and the separations were better under low temperature in most cases. The work is of significance for the investigation of the environmental behaviors of pyriproxyfen on an enantiomeric level. PMID:26773961

  14. Direct Optical Resolution of Chiral Pesticides by High Performance Liquid Chromatography

    Institute of Scientific and Technical Information of China (English)

    LI Xiaogang; LIU Yiping; HU Changdi; BAI Lianyang; GAO Bida; HUANG Kelong

    2011-01-01

    Enantiomer separation is one of the most important prerequisites for the investigation of environmental enantioselective behavior for chiral pesticides.The enantiomeric separation of three chiral pesticides,indoxacarb,lambda-cyhalothrin,and simeconazole,were studied on cellulose tris-(3,5-dimethylphenyl-carbamate)-coated chiral stationary phase(CDMPC-CSP) using high-performance liquid chromatography under normal phase condition.The effects of chromatographic conditions,such as the mobile phase composition including the concentration and type of alcohol modifiers in hexane,flow rate and column temperature,on enantiomer separation were examined.The thermodynamical mechanism of enantioseparation and chiral recognition mechanism were discussed.Better separation were achieved using 20% n-propanol for indoxacarb,2% iso-butanol for lambda-cyhalothrin,and 20% iso-propanol for simeconazole as modifiers in hexane at 25℃ with the selectivity factor(a) of 1.69,1.82 and 1.70,respectively.The resolution factor(Rs) decreased as the flow rate increased from 0.4 to 1.1 ml·min-1.The retention factor(k') and selectivity factor for the enantiomers of analytes decreased as temperature increased.The lna-1/T plots for racemic chiral pesticides were linear in the range of 15-35℃ in hexane/iso-propanol and the chiral separation was controlled by enthalpy.Hydrogen bonding,π-π and dipole-dipole interactions between enantiomers and CDMPC-CSP play an important role in chiral identification,and the fitting of the asymmetric portion of solutes in a chiral cavity or channel of the CSP is also important.

  15. NMR studies of liquids and disordered solids at high pressure

    International Nuclear Information System (INIS)

    Molecular reorientation and translation in molecular liquids was studied. A dominant premise in these studies was that, except in strongly hydrogen-bonded systems such as water, the dynamics of a liquid may be considered to be a series of impulsive collisions. Details of the behavior would be dominated by the shape and size of the molecules under constant packing conditions. The second area of effort was in the plastic crystalline solid phase of two globular molecules, adamantane and cyclohexane. The NMR technique was used in these studies to measure self-diffusion coefficients and spin-lattice relaxation times. The applicability of pulsed NMR techniques to the study of the kinetics of order--disorder phase transitions in solid adamantane was demonstrated

  16. Dispersive liquid-liquid microextraction followed by high-performance liquid chromatography for determination of benzoate and sorbate in yogurt drinks and method optimization by central composite design.

    Science.gov (United States)

    Kamankesh, Marzieh; Mohammadi, Abdorreza; Tehrani, Zohreh Modarres; Ferdowsi, Roohallah; Hosseini, Hedayat

    2013-05-15

    A new method based on dispersive liquid-liquid microextraction (DLLME) followed by high-performance liquid chromatography (HPLC) for determination of benzoate and sorbate salts in yogurt drinks was developed. The effective parameters in DLLME process, including volume of extraction and disperser solvents, pH and salt effect, were optimized using response surface methodology (RSM) based on central composite design. The yogurt drink samples were extracted using NaOH and Carrez solutions (potassium hexaferrocyanide and zinc acetate) were used for sedimentation of proteins. For DLLME, a mixture of extraction solvent (1-octanol) and disperser solvent (ethanol) was rapidly injected into the sample solution by syringe and cloudy solution is formed. Subsequently, the upper 1-octanol layer was analyzed by HPLC. The detection limits for benzoate and sorbate were 0.06 ng mL(-1) and 0.15 ng mL(-1), respectively. The relative standard deviations (RSD) for seven analyses were 4.96% for benzoate and 4.58% for sorbate. The proposed method demonstrated good linearity and high enrichment factor. A clean separation and good chromatogram is readily achieved without the presence of matrix interference. A comparison of this method with previous methods demonstrated that the proposed method is an accurate, rapid and reliable sample-pretreatment method that gives very good enrichment factors and detection limits for extracting and determining sorbate and benzoate in yogurt drink samples. PMID:23618139

  17. Determination of six pyrethroid insecticides in fruit juice samples using dispersive liquid-liquid microextraction combined with high performance liquid chromatography.

    Science.gov (United States)

    Boonchiangma, Suthasinee; Ngeontae, Wittaya; Srijaranai, Supalax

    2012-01-15

    Dispersive liquid-liquid microextraction (DLLME) coupled to high performance liquid chromatography (HPLC) with UV detection was applied for the determination of six pyrethroids (tetramethrin, fenpropathrin, cypermethrin, deltamethrin, fenvalerate and permethrin) in various fruit juices including apple, red grape, orange, kiwi, passion fruit, pomegranate and guava juice. Six pyrethroids were separated within 30 min using a Waters Atlantis T3 column under an isocratic elution of acetonitrile-water (72:28). The parameters affecting extraction efficiency of the DLLME method such as type of disperser and extraction solvent, volume of disperser and extraction solvent and centrifugation time were investigated. Under the optimum conditions, 5.00 mL of sample solution, 300 μL of chloroform as extraction solvent and 1.25 mL of methanol as dispersive solvent gave high enrichment factor in the range of 62-84. Good linearity was obtained from 2 to 1,500 μg/L (r(2)>0.995). The mean recoveries of the pyrethroids evaluated by fortification of real samples were in the range of 84-94%. The limits of detection ranging from 2 to 5 μg/L are sufficient to analyze pyrethroid residues at the maximum residue limits (MRLs) established by the European Union (EU) in fruit juices. The proposed method can be applied to direct determination of pyrethroid residues in fruit juices.

  18. Real-Time, Non-Intrusive Detection of Liquid Nitrogen in Liquid Oxygen at High Pressure and High Flow

    Science.gov (United States)

    Singh, Jagdish P.; Yueh, Fang-Yu; Kalluru, Rajamohan R.; Harrison, Louie

    2012-01-01

    An integrated fiber-optic Raman sensor has been designed for real-time, nonintrusive detection of liquid nitrogen in liquid oxygen (LOX) at high pressures and high flow rates in order to monitor the quality of LOX used during rocket engine ground testing. The integrated sensor employs a high-power (3-W) Melles Griot diode-pumped, solid-state (DPSS), frequency-doubled Nd:YAG 532- nm laser; a modified Raman probe that has built-in Raman signal filter optics; two high-resolution spectrometers; and photomultiplier tubes (PMTs) with selected bandpass filters to collect both N2 and O2 Raman signals. The PMT detection units are interfaced with National Instruments Lab- VIEW for fast data acquisition. Studies of sensor performance with different detection systems (i.e., spectrometer and PMT) were carried out. The concentration ratio of N2 and O2 can be inferred by comparing the intensities of the N2 and O2 Raman signals. The final system was fabricated to measure N2 and O2 gas mixtures as well as mixtures of liquid N2 and LOX

  19. Identification, characterization, and high-performance liquid chromatography quantification of process-related impurities in vonoprazan fumarate.

    Science.gov (United States)

    Liu, Lei; Cao, Na; Ma, Xingling; Xiong, Kaihe; Sun, Lili; Zou, Qiaogen

    2016-04-01

    High-performance liquid chromatography analysis of vonoprazan fumarate, a novel proton pump inhibitor drug revealed six impurities. These were identified by liquid chromatography with mass spectrometry. Further, the structures of the impurities were confirmed by synthesis followed by characterization by mass spectrometry, NMR spectroscopy, and infrared spectroscopy. On the basis of these data and knowledge of the synthetic scheme of vonoprazan fumarate, the previously unknown impurity was identified as 1-[5-(2-fluorophenyl)-1-(pyridin-3-ylsulfonyl)-1H-pyrrol-3-yl]-N-methyldimethylamine, which is a new compound. The possible mechanisms by which these impurities were formed were also discussed. A high-performance liquid chromatography method was optimized in order to separate, selectively detect, and quantify all process-related impurities of vonoprazan fumarate. The presented method has been validated in terms of linearity, limits of detection, and quantification, and response factors and, therefore, is highly suitable for routine analysis of vonoprazan fumarate related substances as well as stability studies.

  20. Preparation of highly purified timosaponin AIII from rhizoma anemarrhenae through an enzymatic method combined with preparative liquid chromatography.

    Science.gov (United States)

    Lu, Lu; Liu, Yanping; Ding, Yue; Hou, Jianwei; Zhang, Yong; Xue, Haiping; Zhang, Tong

    2016-10-01

    Timosaponin AIII (TAIII) exhibits extensive pharmacological activities and has been reported as a potent antitumour agent for various human cancers. In the present study, a potential industrial process for producing TAIII that involves biotransformation directly in the crude extract liquid of rhizoma anemarrhenae (RA) was developed. β-D-glycosidase was used to transform timosaponin BII (TBII) into TAIII, and monofactor experiments were conducted to optimise the enzymolysis conditions. In addition, AB-8 macroporous resin column chromatography, preparative liquid chromatography, and crystallisation technique were applied for yielding TAIII crystals with a purity > 97%. Approximately, 7 g of TAIII with a high purity of > 97% was obtained from 1 kg of RA through this five-step preparation method, which can be used to produce TAIII on a large scale. PMID:27055070

  1. Ultra pressure liquid chromatography-negative electrospray ionization mass spectrometry determination of twelve halobenzoquinones at ng/L levels in drinking water.

    Science.gov (United States)

    Huang, Rongfu; Wang, Wei; Qian, Yichao; Boyd, Jessica M; Zhao, Yuli; Li, Xing-Fang

    2013-05-01

    We report here the characterization of twelve halobenzoquinones (HBQs) using electrospray ionization (ESI) high resolution quadrupole time-of-flight mass spectrometry. The high resolution negative ESI spectra of the twelve HBQs formed two parent ions, [M + H(+) + 2e(-)], and the radical M(-•). The intensities of these two parent ions are dependent on their chemical structures and on instrumental parameters such as the source temperature and flow rate. The characteristic ions of the HBQs were used to develop an ultra pressure liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method. At the UPLC flow rate (400 μL/min) and under the optimized ESI conditions, eleven HBQs showed the stable and abundant transitions [M + H(+) + 2e(-)] → X(-) (X(-) representing Cl(-), Br(-), or I(-)), while dibromo-dimethyl-benzoquinone (DBDMBQ) showed only the transition of M(-•) → Br(-). The UPLC efficiently separates all HBQs including some HBQ isomers, while the MS/MS offers exquisite limits of detection (LODs) at subng/mL levels for all HBQs except DBDMBQ. Combined with solid phase extraction (SPE), the method LOD is down to ng/L. The results from analysis of authentic samples demonstrated that the SPE-UPLC-MS/MS method is reliable, fast, and sensitive for the identification and quantification of the twelve HBQs in drinking water.

  2. Measurement and modeling of high-pressure (vapour + liquid) equilibria of (CO2 + alcohol) binary systems

    International Nuclear Information System (INIS)

    An apparatus based on a static-analytic method assembled in this work was utilized to perform high pressure (vapour + liquid) equilibria measurements with uncertainties estimated at 2 + 1-propanol), (CO2 + 2-methyl-1-propanol), (CO2 + 3-methyl-1-butanol), and (CO2 + 1-pentanol) binary systems at temperatures of (313, 323, and 333) K, and at pressure range of (2 to 12) MPa. For all the (CO2 + alcohol) systems, it was visually monitored to insure that there was no liquid immiscibility at the temperatures and pressures studied. The experimental results were correlated with the Peng-Robinson equation of state using the quadratic mixing rules of van der Waals with two adjustable parameters. The calculated (vapour + liquid) equilibria compositions were found to be in good agreement with the experimental values with deviations for the mol fractions <0.12 and <0.05 for the liquid and vapour phase, respectively.

  3. Trace analysis of some organophosphorus pesticides in rice samples using ultrasound-assisted dispersive liquid-liquid microextraction and high-performance liquid chromatography.

    Science.gov (United States)

    Sharafi, Kiomars; Fattahi, Nazir; Mahvi, Amir Hossein; Pirsaheb, Meghdad; Azizzadeh, Nahid; Noori, Masomeh

    2015-03-01

    An ultrasound-assisted dispersive liquid-liquid microextraction based on solidification of a floating organic drop method followed by high-performance liquid chromatography was developed for the extraction, preconcentration, and determination of trace amounts of organophosphorus pesticides in rice samples. Variables affecting the performance of both steps were thoroughly investigated. Some effective parameters on extraction were studied and optimized. Under the optimum conditions, recoveries for rice sample are in the range of 58.0-66.0%. The calibration graphs are linear in the range of 4-800 μg/kg and, limits of detection and limits of quantification are in the range of 1.5-3 and 4.2-8.5 μg/kg, respectively. The relative standard deviation for 50.0 μg/kg of organophosphorus pesticides in rice sample are in the range of 4.4-5.1% (n = 5). The obtained results show that proposed method is a fast and simple method for the determination of pesticides in cereals. PMID:25641828

  4. [Simultaneous determination of four phthalate esters in water samples using ultrasound-assisted dispersive liquid-liquid microextraction coupled with high performance liquid chromatography].

    Science.gov (United States)

    Ma, Yanling; Chen, Lingxin; Ding, Yangjun; Ming, Yongfei; Li, Jinhua

    2013-02-01

    Ultrasound-assisted dispersive liquid-liquid microextraction coupled with high performance liquid chromatography (UA-DLLME-HPLC) was developed for the determination of four typical phthalate esters (PAEs). The analyzed PAEs included dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP) and di-n-octyl phthalate (DnOP). The UA-DLLME parameters such as types/volumes of extraction/dispersion solvents, ultrasonic time, ionic strength and extraction time, were investigated. Enrichment factor (EF)was employed to evaluate the extraction efficiency. The conditions were finally chosen: CCl4 (40 microL)/ acetonitrile (1.0 mL) as extraction/dispersion solvents; 30 g/L NaCl; ultrasound/centrifugation of 5 min. Under the optimized extraction conditions, UA-DLLME exhibited strong enrichment ability for the four PAEs. The EFs for DMP, DEP, DBP and DnOP obtained were 71, 144, 169 and 159, respectively. The limits of detection were 3.78, 1.77, 3.07 and 3.30 microg/L for DMP, DEP, DBP and DnOP, respectively. The satisfactory recoveries for three water samples at three spiked levels ranged from 82.99%-114.47%, with the relative standard deviations of 1.93%-8.31%. It is a convenient, speedy, environmentally benign method for the routine analysis of PAEs in water samples. PMID:23697182

  5. Pipette vial dispersive liquid-liquid microextraction combined with high-performance liquid chromatography for the determination of benzoylurea insecticide in fruit juice.

    Science.gov (United States)

    Xi, Xuefei; Yang, Miyi; Shen, Ganni; Wu, Xiaoling; Lu, Runhua; Zhou, Wenfeng; Zhang, Sanbing; Gao, Haixiang

    2016-01-01

    A simple, sensitive, and efficient method of using a pipette vial to perform dispersive liquid-liquid microextraction based on the solidification of floating organic droplets was coupled with high-performance liquid chromatography (HPLC) and a diode array detector for the preconcentration and analysis of four benzoylurea insecticides in fruit juice. In this method, 1-dodecanol was used as an extractant, and a snipped pipette was used as an experimental vial to simplify the procedure of collecting and separating solidified extractant. The experimental parameters were optimized using a Plackett-Burman design and one-factor-at-a-time method. Under the optimal conditions in the water model, the limits of detection for analytes varied from 0.03 to 0.28 μg/L, and the enrichment factors ranged from 147 to 206. Linearity was achieved for diflubenzuron and flufenoxuron in a range of 0.5-500 μg/L, for hexaflumuron in a range of 1-500 μg/L, and for triflumuron in a range of 5-500 μg/L. The correlation coefficients for the analytes ranged from 0.9986 to 0.9994 with recoveries of 91.4-110.9%. Finally, the developed technique was successfully applied to fruit juice samples with acceptable results. The relative standard deviations of the analytes at two spiking levels (50 and 200 μg/L) varied between 0.2 and 4.5%. PMID:26526571

  6. Novel method for the determination of five carbamate pesticides in water samples by dispersive liquid-liquid microextraction combined with high performance liquid chromatography

    Institute of Scientific and Technical Information of China (English)

    Zhi Mei Liu; Xiao Huan Zang; Wei Hua Liu; Chun Wang; Zhi Wang

    2009-01-01

    A novel method for the determination of five carbamate pesticides(metolcarb,carbofuran,carbaryl,isoprocard and diethofencard)in water samples was developed by dispersive liquid-liquid microextraction(DLLME)coupled with high performance liquid chromatography-diode array detector(HPLC-DAD).Some experimental parameters that influence the extraction efficiency were studied and optimized to obtain the best extraction results.Under the optimum conditions for the method,the calibration curve was linear in the concentration range from 5 to I000 ng mL-1 for all the five carbamate pesticides,with the correlation coefficients(r2)varying from 0.9984 to 0.9994.Good enrichment factors were achieved ranging from 80 to 177-fold,depending on the compound.The limits of detection(LODs)(S/N = 3)were ranged from 0.1 to 0.5 ng mL-1.The method has been successfully applied to the analysis of the pesticide residues in environmental water samples.

  7. Simultaneous determination of six synthetic phenolic antioxidants in edible oils using dispersive liquid-liquid microextraction followed by high-performance liquid chromatography with diode array detection.

    Science.gov (United States)

    Xu, Shuangjiao; Liu, Liangliang; Wang, Yanqin; Zhou, Dayun; Kuang, Meng; Fang, Dan; Yang, Weihua; Wei, Shoujun; Xiao, Aiping; Ma, Lei

    2016-08-01

    A simple, rapid, organic-solvent- and sample-saving pretreatment technique, called dispersive liquid-liquid microextraction, was developed for the determination of six synthetic phenolic antioxidants from edible oils before high-performance liquid chromatography with diode array detection. The entire procedure was composed of a two-step microextraction and a centrifugal process and could be finished in about 5 min, only consuming only 25 mg of sample and 1 mL of the organic solvent for each extraction. The influences of several important parameters on the microextraction efficiency were thoroughly investigated. Recovery assays for oil samples were spiked at three concentration levels, 50, 100 and 200 mg/kg, and provided recoveries in the 86.3-102.5% range with a relative standard deviation below 3.5%. The intra-day and inter-day precisions for the analysis were less than 3.8%. The proposed method was successfully applied for the determination of synthetic phenolic antioxidants in different oil samples, and satisfactory results were obtained. Thus, the developed method represents a viable alternative for the quality control of synthetic phenolic antioxidant concentrations in edible oils.

  8. Pipette vial dispersive liquid-liquid microextraction combined with high-performance liquid chromatography for the determination of benzoylurea insecticide in fruit juice.

    Science.gov (United States)

    Xi, Xuefei; Yang, Miyi; Shen, Ganni; Wu, Xiaoling; Lu, Runhua; Zhou, Wenfeng; Zhang, Sanbing; Gao, Haixiang

    2016-01-01

    A simple, sensitive, and efficient method of using a pipette vial to perform dispersive liquid-liquid microextraction based on the solidification of floating organic droplets was coupled with high-performance liquid chromatography (HPLC) and a diode array detector for the preconcentration and analysis of four benzoylurea insecticides in fruit juice. In this method, 1-dodecanol was used as an extractant, and a snipped pipette was used as an experimental vial to simplify the procedure of collecting and separating solidified extractant. The experimental parameters were optimized using a Plackett-Burman design and one-factor-at-a-time method. Under the optimal conditions in the water model, the limits of detection for analytes varied from 0.03 to 0.28 μg/L, and the enrichment factors ranged from 147 to 206. Linearity was achieved for diflubenzuron and flufenoxuron in a range of 0.5-500 μg/L, for hexaflumuron in a range of 1-500 μg/L, and for triflumuron in a range of 5-500 μg/L. The correlation coefficients for the analytes ranged from 0.9986 to 0.9994 with recoveries of 91.4-110.9%. Finally, the developed technique was successfully applied to fruit juice samples with acceptable results. The relative standard deviations of the analytes at two spiking levels (50 and 200 μg/L) varied between 0.2 and 4.5%.

  9. Combination of saponification and dispersive liquid-liquid microextraction for the determination of tocopherols and tocotrienols in cereals by reversed-phase high-performance liquid chromatography.

    Science.gov (United States)

    Shammugasamy, Balakrishnan; Ramakrishnan, Yogeshini; Ghazali, Hasanah M; Muhammad, Kharidah

    2013-07-26

    A simple sample preparation technique coupled with reversed-phase high-performance liquid chromatography was developed for the determination of tocopherols and tocotrienols in cereals. The sample preparation procedure involved a small-scale hydrolysis of 0.5g cereal sample by saponification, followed by the extraction and concentration of tocopherols and tocotrienols from saponified extract using dispersive liquid-liquid microextraction (DLLME). Parameters affecting the DLLME performance were optimized to achieve the highest extraction efficiency and the performance of the developed DLLME method was evaluated. Good linearity was observed over the range assayed (0.031-4.0μg/mL) with regression coefficients greater than 0.9989 for all tocopherols and tocotrienols. Limits of detection and enrichment factors ranged from 0.01 to 0.11μg/mL and 50 to 73, respectively. Intra- and inter-day precision were lower than 8.9% and the recoveries were around 85.5-116.6% for all tocopherols and tocotrienols. The developed DLLME method was successfully applied to cereals: rice, barley, oat, wheat, corn and millet. This new sample preparation approach represents an inexpensive, rapid, simple and precise sample cleanup and concentration method for the determination of tocopherols and tocotrienols in cereals.

  10. Simultaneous determination of six synthetic phenolic antioxidants in edible oils using dispersive liquid-liquid microextraction followed by high-performance liquid chromatography with diode array detection.

    Science.gov (United States)

    Xu, Shuangjiao; Liu, Liangliang; Wang, Yanqin; Zhou, Dayun; Kuang, Meng; Fang, Dan; Yang, Weihua; Wei, Shoujun; Xiao, Aiping; Ma, Lei

    2016-08-01

    A simple, rapid, organic-solvent- and sample-saving pretreatment technique, called dispersive liquid-liquid microextraction, was developed for the determination of six synthetic phenolic antioxidants from edible oils before high-performance liquid chromatography with diode array detection. The entire procedure was composed of a two-step microextraction and a centrifugal process and could be finished in about 5 min, only consuming only 25 mg of sample and 1 mL of the organic solvent for each extraction. The influences of several important parameters on the microextraction efficiency were thoroughly investigated. Recovery assays for oil samples were spiked at three concentration levels, 50, 100 and 200 mg/kg, and provided recoveries in the 86.3-102.5% range with a relative standard deviation below 3.5%. The intra-day and inter-day precisions for the analysis were less than 3.8%. The proposed method was successfully applied for the determination of synthetic phenolic antioxidants in different oil samples, and satisfactory results were obtained. Thus, the developed method represents a viable alternative for the quality control of synthetic phenolic antioxidant concentrations in edible oils. PMID:27334034

  11. Vortex-assisted liquid-liquid microextraction coupled with high performance liquid chromatography for the determination of furfurals and patulin in fruit juices.

    Science.gov (United States)

    Abu-Bakar, Nur-Bahiyah; Makahleh, Ahmad; Saad, Bahruddin

    2014-03-01

    A fast and simple solvent microextraction technique using salting out-vortex-assisted liquid-liquid microextraction (salting out-VALLME) was developed for the extraction of furfurals (2-furfural (2-F), 3-furfural (3-F), 5-methylfurfural (5-MF) and 5-hydroxymethylfurfural (5-HMF)) and patulin (PAT) in fruit juice samples. The optimum extraction conditions for 5 mL sample were: extraction solvent, 1-hexanol; volume of extractant, 200 µL; vortex time, 45 s; salt addition, 20%. The simultaneous determination of the furfurals and PAT were investigated using high performance liquid chromatography coupled with diode array detector (HPLC-DAD). The separation was performed using ODS Hypersil C18 column (4.6 mm i.d × 250 mm, 5 μm) under gradient elution. The detection wavelengths used for all compounds were 280 nm except for 3-F (210 nm). The furfurals and PAT were successfully separated in less than 9 min. Good linearities (r(2)>0.99) were obtained within the range 1-5000 μg L(-1) for all compounds except for 3-F (10-5000 µg L(-1)) and PAT (0.5-100 μg L(-1)). The limits of detection (0.28-3.2 µg L(-1)) were estimated at S/N ratio of 3. The validated salting out-VALLME-HPLC method was applied for the analysis of furfurals and PAT in fruit juice samples (apple, mango and grape). PMID:24468341

  12. [Determination of congo red in beef by high performance liquid chromatography-tandem quadrupole time of flight mass spectrometry and ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry].

    Science.gov (United States)

    Lin, Hui; Xu, Chunxiang; Yan, Chunrong; Zhang, Zheng; Wang, Suilou

    2013-09-01

    A method was developed for the determination of congo red in beef. The analyte was identified by high performance liquid chromatography-tandem quadrupole time of flight mass spectrometry (LC-QTOF MS) and quantitatively determined by ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry. After purified by liquid-liquid extraction, the congo red in the beef sample was separated on an Agilent ZORBAX Eclipse Plus C18 Rapid Resolution HD UPLC column (50 mm x 2.1 mm, 1.8 microm) HPLC , using 95% (volume percentage) methanol as the mobile phase at 0.2 mL/min. The detection was performed on an AB 4000 + triple quadrupole mass spectrometer utilizing electrospray ionization (ESI) interface operated in negative ion mode and multiple-reaction monitoring (MRM) mode. The results showed that the linear range of congo red mass concentration was 0.03 - 1 mg/L with the correlation coefficient of 0.999 8. The method had a good precision with the RSDs lower than 5% and the recoveries ranging from 88% to 91%. The limit of detection (LOD) of congo red was 0.01 mg/L. With good reproducibility, the method is simple, fast and effective for the determination of the illegally added congo red in beef and other meat products.

  13. Phase Transitions of Triflate-Based Ionic Liquids under High Pressure.

    Science.gov (United States)

    Faria, Luiz F O; Ribeiro, Mauro C C

    2015-11-01

    Raman spectroscopy has been used to study phase transitions of ionic liquids based on the triflate anion, [TfO](-), as a function of pressure or temperature. Raman spectra of ionic liquids containing the cations 1-butyl-3-methylimidazolium, [C4C1Im](+), 1-octyl-3-methylimidazolium, [C8C1Im](+), 1-butyl-2,3-dimethylimidazolium, [C4C1C1Im](+), and 1-butyl-1-methylpyrrolidinium, [C4C1Pyr](+), were compared. Vibrational frequencies and binding energy of ionic pairs were calculated by quantum chemistry methods. The ionic liquids [C4C1Im][TfO] and [C4C1Pyr][TfO] crystallize at 1.0 GPa when the pressure is increased in steps of ∼ 0.2 GPa from the atmospheric pressure, whereas [C8C1Im][TfO] and [C4C1C1Im][TfO] do not crystallize up to 2.3 GPa of applied pressure. The low-frequency range of the Raman spectrum of [C4C1Im][TfO] indicates that the system undergoes glass transition, rather than crystallization, when the pressure applied on the liquid has been increased above 2.0 GPa in a single step. Strong hysteresis of spectral features (frequency shift and bandwidth) of the high-pressure crystalline phase when the pressure was released stepwise back to the atmospheric pressure has been found . PMID:26457868

  14. Rapid determination of organochlorine pesticides in fish using selective pressurized liquid extraction and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Choi, Minkyu; Lee, In-Seok; Jung, Rae-Hong

    2016-08-15

    A rapid automated extraction and cleanup method using selective pressurized liquid extraction was developed and validated for 14 organochlorine pesticides in fish. The lipid-removal efficiencies achieved by adding alumina, Florisil, acid-treated silica gel, and silica gel to the extraction cell were determined and optimized. In the optimized method, fish (2-3g) was placed above alumina (30 g) in the extraction cell, then the sample was extracted using a 7:3 mixture of hexane and dichloromethane. The method was validated using certified reference materials (NIST SRM 1946 and 1974c), spiked fish, and four lipid-rich fish samples. The mean low- and high-concentration spike recoveries were 91% and 93% with RSD<20%, respectively. Measured concentrations of target OCPs showed good agreement with the certified concentrations in certified reference materials. It suggests the good accuracy and precision of the SPLE method. The proposed method met the most important requirements of an extraction and cleanup procedure, including having a short preparation (cleanup and concentration) time and minimal sample contamination and being able to be automated. PMID:27006206

  15. High Performance Liquid Chromatography-mass Spectrometry Analysis of High Antioxidant Australian Fruits with Antiproliferative Activity Against Cancer Cells

    Science.gov (United States)

    Sirdaarta, Joseph; Maen, Anton; Rayan, Paran; Matthews, Ben; Cock, Ian Edwin

    2016-01-01

    g/mL). All other extracts were nontoxic. A total of 145 unique mass signals were detected in the lemon aspen methanolic and aqueous extracts by nonbiased high-performance liquid chromatography-mass spectrometry analysis. Of these, 20 compounds were identified as being of particular interest due to their reported antioxidant and/or anticancer activities. Conclusions: The lack of toxicity and antiproliferative activity of the high antioxidant plant extracts against HeLa and CaCo2 cancer cell lines indicates their potential in the treatment and prevention of some cancers. SUMMARY Australian fruit extracts with high antioxidant contents were potent inhibitors of CaCo2 and HeLa carcinoma cell proliferationMethanolic lemon aspen extract was particularly potent, with IC50 values of 480 μg/mL (HeLa) and 769 μg/mL (CaCo2)High-performance liquid chromatography-mass spectrometry-quadrupole time-of-flight analysis highlighted and putatively identified 20 compounds in the antiproliferative lemon aspen extractsIn contrast, lower antioxidant content extracts stimulated carcinoma cell proliferationAll extracts with antiproliferative activity were nontoxic in the Artemia nauplii assay. Abbreviations used: DPPH: di (phenyl)- (2,4,6-trinitrophenyl) iminoazanium, HPLC: High-performance liquid chromatography, IC50: The concentration required to inhibit by 50%, LC50: The concentration required to achieve 50% mortality, MS: Mass spectrometry. PMID:27279705

  16. Qualitative and Quantitative Analysis of Volatile Components of Zhengtian Pills Using Gas Chromatography Mass Spectrometry and Ultra-High Performance Liquid Chromatography

    Science.gov (United States)

    Liu, Cui-ting; Zhang, Min; Yan, Ping; Liu, Hai-chan; Liu, Xing-yun; Zhan, Ruo-ting

    2016-01-01

    Zhengtian pills (ZTPs) are traditional Chinese medicine (TCM) which have been commonly used to treat headaches. Volatile components of ZTPs extracted by ethyl acetate with an ultrasonic method were analyzed by gas chromatography mass spectrometry (GC-MS). Twenty-two components were identified, accounting for 78.884% of the total components of volatile oil. The three main volatile components including protocatechuic acid, ferulic acid, and ligustilide were simultaneously determined using ultra-high performance liquid chromatography coupled with diode array detection (UHPLC-DAD). Baseline separation was achieved on an XB-C18 column with linear gradient elution of methanol-0.2% acetic acid aqueous solution. The UHPLC-DAD method provided good linearity (R2 ≥ 0.9992), precision (RSD protocatechuic acid, ferulic acid, and ligustilide, in 13 batches of ZTPs, which is suitable for discrimination and quality assessment of ZTPs. PMID:26904360

  17. Comparison of ultra-high performance supercritical fluid chromatography and ultra-high performance liquid chromatography for the separation of spirostanol saponins.

    Science.gov (United States)

    Zhu, Ling-Ling; Zhao, Yang; Xu, Yong-Wei; Sun, Qing-Long; Sun, Xin-Guang; Kang, Li-Ping; Yan, Ren-Yi; Zhang, Jie; Liu, Chao; Ma, Bai-Ping

    2016-02-20

    Spirostanol saponins are important active components of some herb medicines, and their isolation and purification are crucial for the research and development of traditional Chinese medicines. We aimed to compare the separation of spirostanol saponins by ultra-high performance supercritical fluid chromatography (UHPSFC) and ultra-high performance liquid chromatography (UHPLC). Four groups of spirostanol saponins were separated respectively by UHPSFC and UHPLC. After optimization, UHPSFC was performed with a HSS C18 SB column or a Diol column and with methanol as the co-solvent. A BEH C18 column and mobile phase containing water (with 0.1% formic acid) and acetonitrile were used in UHPLC. We found that UHPSFC could be performed automatically and quickly. It is effective in separating the spirostanol saponins which share the same aglycone and vary in sugar chains, and is very sensitive to the number and the position of hydroxyl groups in aglycones. However, the resolution of spirostanol saponins with different aglycones and the same sugar moiety by UHPSFC was not ideal and could be resolved by UHPLC instead. UHPLC is good at differentiating the variation in aglycones, and is influenced by double bonds in aglycones. Therefore, UHPLC and UHPSFC are complementary in separating spirostanol saponins. Considering the naturally produced spirostanol saponins in herb medicines are different both in aglycones and in sugar chains, a better separation can be achieved by combination of UHPLC and UHPSFC. UHPSFC is a powerful technique for improving the resolution when UHPLC cannot resolve a mixture of spirostanol saponins and vice versa.

  18. Development and validation of high-performance liquid chromatography and high-performance thin-layer chromatography methods for the quantification of khellin in Ammi visnaga seed

    Directory of Open Access Journals (Sweden)

    Abid Kamal

    2015-01-01

    Full Text Available Objective: The present study was used to design simple, accurate and sensitive reversed phase-high-performance liquid chromatography RP-HPLC and high-performance thin-layer chromatography (HPTLC methods for the development of quantification of khellin present in the seeds of Ammi visnaga. Materials and Methods: RP-HPLC analysis was performed on a C18 column with methanol: Water (75: 25, v/v as a mobile phase. The HPTLC method involved densitometric evaluation of khellin after resolving it on silica gel plate using ethyl acetate: Toluene: Formic acid (5.5:4.0:0.5, v/v/v as a mobile phase. Results: The developed HPLC and HPTLC methods were validated for precision (interday, intraday and intersystem, robustness and accuracy, limit of detection and limit of quantification. The relationship between the concentration of standard solutions and the peak response was linear in both HPLC and HPTLC methods with the concentration range of 10–80 μg/mL in HPLC and 25–1,000 ng/spot in HPTLC for khellin. The % relative standard deviation values for method precision was found to be 0.63–1.97%, 0.62–2.05% in HPLC and HPTLC for khellin respectively. Accuracy of the method was checked by recovery studies conducted at three different concentration levels and the average percentage recovery was found to be 100.53% in HPLC and 100.08% in HPTLC for khellin. Conclusions: The developed HPLC and HPTLC methods for the quantification of khellin were found simple, precise, specific, sensitive and accurate which can be used for routine analysis and quality control of A. visnaga and several formulations containing it as an ingredient.

  19. Determination of Vanillin from Tincture and Extract Products of Vanilla by Using Reversed Phase High Pressure Liquid Chromatography%反相高效液相色谱法检测香草兰豆酊、浸膏中香兰素

    Institute of Scientific and Technical Information of China (English)

    卢少芳; 初众; 赵建平

    2009-01-01

    采用反相高效液相色谱法测定香草兰豆酊、浸膏中香兰素含量,色谱柱为C_(18)柱,甲醇/0.5%冰乙酸水溶液(20/80.v/v)为流动相,等浓度洗脱,测定波长为280 nm,外标法定量.该方法相对标准偏差分别为0.28%和0.24%.加标回收率为97.89%~100.71%.本方法具有操作简便,结果准确等优点,特别适用于香草兰豆酊、浸膏等精深加工产品中香兰素含量的检测分析.%A simple, rapid and accurate method was developed for determination of vanillin by Reversed Phase High Pressure Liquid Chromatography. In this method chromatographic column was C18, mobile phase methanol/0.5% acetic acid (20/80, v/v), elution isocratic, wavelength 280nm, External Standard for quantification. With this method the relative standard deviation was 0.28% for detection of the samples of vanilla tincture and 0.24% for detection of the samples of vanilla extract, and the spike recovery rate ranged from 98.89% to 100.71%. This method is good for determination of vanillin from the well-processed vanilla tincture and the vanilla extract.

  20. Liquid phase chromatography on microchips

    DEFF Research Database (Denmark)

    Kutter, Jörg Peter

    2012-01-01

    explosive development of, in particular, chromatographic separation systems on microchips, has, however, slowed down in recent years. This review takes a closer, critical look at how liquid phase chromatography has been implemented in miniaturized formats over the past several years, what is important...

  1. Determination of coumarin anticoagulant rodenticide residues in animal tissue by high-performance liquid chromatography. II. fluorescence detection using ion-pair chromatography.

    Science.gov (United States)

    Hunter, K

    1983-11-18

    A high-performance liquid chromatographic method was developed for the determination of warfarin, coumatetralyl, bromadiolone, difenacoum and brodifacoum in animal tissues using fluorescence detection. Ion-pair chromatography, with the tetrabutylammmonium ion as counter-ion, was used to take full advantage of their native fluorescence. Detection limits in liver tissue after gel permeation clean-up were 0.002 mg kg-1 for coumatetralyl, difenacoum and bromdifacoum, 0.008 mg kg-1 for bromadiolone, and 0.01 mg kg-1 for warfarin. PMID:6655020

  2. Characterization of phenolic amides from cortex lycii by ultra high-performance liquid chromatography coupled with LTQ-Orbitrap mass spectrometry

    Science.gov (United States)

    High performance liquid chromatography (UPLC) and flow injection electrospray ionization with ion trap mass spectrometry (FIMS) fingerprints combined with the principal component analysis (PCA) were examined for their potential in differentiating commercial organic and conventional sage samples. The...

  3. Arsenic speciation in seafood samples with emphasis on minor constituents. An investigation by high performance liquid chromatography with inductively coupled plasma mass spectrometric detection

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Pritzl, G.; Hansen, S. H.

    1993-01-01

    Extracts of 11 samples of shrimp, crab, fish, fish liver, shellfish and lobster digestive gland (hepatopancreas), including five certified reference materials, were investigated for their contents of arsenic compounds (arsenic speciation). The cation-exchange high performance liquid chromatography...

  4. Electrical length of sulphur hexafluoride (SF6) at high pressure and at the liquid state

    International Nuclear Information System (INIS)

    Author.Breakdown voltage of liquid SF6 at pressures higher than the critical one was measured. At the same time, investigations of electrical strength of gas SF6 at low and high densities (from 27 g/L to 1194g/L) were carried out for temperature T=50 oC, 60 oC. Breakdown voltage was measured with Rogowski profile electrodes at distances 0.4 mm. For low and high density SF6 gas. Good agreement was found between measured and calculated values by using a simple ionization development model for discharge initiation and microirregularities effect on the electrode surface structure. For liquid SF6 at pressure higher and lower than the critical one. It is supposed that the breakdown in the liquid occurs as result of a breakdown of bubbles which assumed that appears spontaneously in a local volume of liquid over heated caused by prebreak down currents

  5. Determination of microsomal CYP2A6 activity by high performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Lavhekar S

    2007-01-01

    Full Text Available Coumarin has been reported to be a reliable probe for the determination of human microsomal CYP2A6 activity. Coumarin is converted to 7-hydroxycoumarin by CYP2A6. A high pressure liquid chromatographic assay for the estimation of CYP2A6 activity in microsomes was evaluated. A RP C-18 Novapak Waters (15 cm x 3.9 mm, 5 µm column was used for the assay. The mobile phase composition was methanol : 1% glacial acetic acid (35:65 v/v (pH~3.1, with a flow rate of 0.6 ml/min, injection volume of 100 µl and detection at 320 nm. The retention times for coumarin and 7-hydroxycoumarin were 8.7 min and 5.3 min, respectively. The limit of detection (LOD was 0.05 µM, and the limit of quantitation (LOQ was 0.1 µM, for 7-hydroxycoumarin. The percent coefficient of variation associated with 7-hydroxycoumarin determination after duplicate estimation was found to be in the range 0.03 to 3.6% for buffer matrix and 0.1 to 6.5% for microsomal matrix. The mean rate of 7-hydroxycoumarin formation in guinea pig liver microsomes was 0.084 nmol/min/nmol P450. Coumarin 7-hydroxylase activity was absent in rat liver microsomes. No interference was observed from incubation mixture components.

  6. Development and validation of methodology for technetium-99m radiopharmaceuticals using high performance liquid chromatography (HPLC)

    International Nuclear Information System (INIS)

    Radiopharmaceuticals are compounds, with no pharmacological action, which have a radioisotope in their composition and are used in Nuclear Medicine for diagnosis and therapy of several diseases. In this work, the development and validation of an analytical method for 99mTc-HSA, 99mTc-EC, 99mTc-ECD and 99mTc-Sestamibi radiopharmaceuticals and for some raw materials were carried out by high performance liquid chromatography (HPLC). The analyses were performed in a Shimadzu HPLC equipment, LC-20AT Prominence model. Some impurities were identified by the addition of a reference standard substance. Validation of the method was carried out according to the criteria defined in RE n. 899/2003 of the National Sanitary Agency (ANVISA). The results for robustness of the method showed that it is necessary to control flow rate conditions, sample volume, pH of the mobile phase and temperature of the oven. The analytical curves were linear in the concentration ranges, with linear correlation coefficients (r2) above 0.9995. The results for precision, accuracy and recovery showed values in the range of 0.07-4.78%, 95.38-106.50% and 94.40-100.95%, respectively. The detection limits and quantification limits varied from 0.27 to 5.77 μg mL-1 and 0.90 to 19.23 μg mL-1, respectively. The values for HAS, EC, ECD and MIBI in the lyophilized reagents were 8.95; 0.485; 0.986 and 0.974 mg L-1, respectively. The mean radiochemical purity for 99mTc-HSA, 99mTc-EC, 99mTc-ECD and 99mTc-Sestamibi was (97.28 ± 0.09)%, (98.96 ± 0.03)%, (98.96 ± 0.03)% and (98.07 ± 0.01)%, respectively. All the parameters recommended by ANVISA were evaluated and the results are below the established limits. (author)

  7. Determination of theoretical retention times for peptides analyzed by reversed- -phase high-performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Jerzy Dziuba

    2011-06-01

    Full Text Available   Background. Peptides are important components of foods mainly due to their biological activity. The basic method of their identification is reversed phase high-performance liquid chromatography coupled with electrospray-ionization mass spectrometry (RP-HPLC-ESI-MS. Retention time (tR prediction in silico is very helpful in analysis of multicomponent peptide mixtures. One of problems associated with RP-HPLC-ESI-MS is deterioration of mass spectra quality by trifluoroacetic acid (TFA. This problem can be avoided through the use of chromatographic columns designed for work with low TFA concentrations in mobile phase. The objective of this study was to determine the correlations between peptide retention times predicted with the use of a program available on-line and experimental retention times obtained using the column working with low TFA concentrations. Material and methods. The set of synthetic peptides and bovine α-lactalbumin fragments (18 peptides was used in the experiment. Theoretical retention times were calculated using Sequence Specific Retention Calculator (SSRC program. The experimental retention times were measured via RP-HPLC-ESI-MS method using column working with low TFA content. The dependence between theoretical and experimental tR was expressed via empirical equations. Results. The best correlation between theoretical and experimental retention times of peptides containing at least four amino acid residues has been obtained when third order polynomial (R² = 0.9536. Prediction quality for di- and tripeptides was significantly lower. The method described can be applied for cysteine-containing peptides although our sample preparation procedure did not include modification of this amino acid, taken into attention by SSRC program. Conclusions. The results of this study validate the usefulness of a third degree polynomial as a simple function describing the correlation between peptide retention times predicted by an on

  8. Quantitation of artemether in pharmaceutical raw material and injections by high performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Isabela da Costa César

    2009-12-01

    Full Text Available The quantitation of artemether in both pharmaceutical raw material and injections was carried out by high performance liquid chromatography (HPLC with ultraviolet detection. A Zorbax C18 column (150 x 4.6 mm; 5 μm, at 30 °C, and a mobile phase composed of acetonitrile and water (70:30, at a flow rate of 1ml/min, were used. The detection wavelength was 216 nm and the injection volume was 20 μL. The method proved to be linear (r²=0.9999, precise (RSD A quantificação de artemeter em matéria-prima farmacêutica e solução injetável foi realizada por cromatografia líquida de alta eficiência (CLAE com detecção na região do ultravioleta. Empregou-se coluna Zorbax C18 (150 x 4.6 mm; 5 μm, mantida a 30 °C, e fase móvel composta por acetonitrila e água (70:30, com fluxo de 1 ml/min. A detecção foi realizada a 216 nm, e o volume de injeção foi 20 μl. O método se mostrou linear (r²=0,9999, preciso (DPR < 2,0% para precisão intra-dia e inter-dias e seletivo em relação a possíveis impurezas e excipientes das amostras. Os limites de detecção e quantificação obtidos foram 8 μg/mL e 25 μg/mL, respectivamente. O teor médio de artemeter obtido na análise da matéria-prima farmacêutica foi 99,26% e na solução injetável, 102,08%. O método otimizado e validado pode ser utilizado com sucesso para análises rotineiras em controle de qualidade.

  9. Determination of atenolol in human plasma using ionic-liquid-based ultrasound-assisted in situ solvent formation microextraction followed by high-performance liquid chromatography.

    Science.gov (United States)

    Zeeb, Mohsen; Farahani, Hadi; Papan, Mohammad Kazem

    2016-06-01

    An efficient analytical method called ionic-liquid-based ultrasound-assisted in situ solvent formation microextraction followed by high-performance liquid chromatography was developed for the determination of atenolol in human plasma. A hydrophobic ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) was formed by the addition of a hydrophilic ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate) to a sample solution containing an ion-pairing agent during microextraction. The analyte was extracted into the ionic liquid phase while the microextraction solvent was dispersed throughout the sample by utilizing ultrasound. The sample was then centrifuged, and the extracting phase retracted into the microsyringe and injected to liquid chromatography. After optimization, the calibration curve showed linearity in the range of 2-750 ng/mL with the regression coefficient corresponding to 0.998. The limits of detection (S/N = 3) and quantification (S/N = 10) were 0.5 and 2 ng/mL, respectively. A reasonable relative recovery range of 90-96.7% and satisfactory intra-assay (4.8-5.1%, n = 6) and interassay (5.0-5.6%, n = 9) precision along with a substantial sample clean-up demonstrated good performance of the procedure. It was applied for the determination of atenolol in human plasma after oral administration and some pharmacokinetic data were obtained.

  10. Determination of total L-Ascorbic Acid by high performance liquid chromatography in human plasma

    Directory of Open Access Journals (Sweden)

    Oveisi MR

    2001-07-01

    Full Text Available The total vitamin C content in human plasma is widely accepted as an indicator of the tissue status of vitamin C. A liquid chromatography method with ultraviolet detector (264 nm for measuring ascorbic acid in human plasma was developed. A C18 reversed-phase column and cetrimide as an ion-pairing agent was employed. Ascorbic acid (AA was measured after reducing L-dehydroascorbic acid to L-ascorbic acid with dithiothreitol. The stability of the ascorbic acid in plasma, metaphosphoric acid and trichloroacetic acid was also evaluated. The analytical parameters, including linearity (1-60 µg/ml, accuracy (98.98%, repeatability (2.8% and reproducibility (7.2%, showed that the method is reliable for measuring the total vitamin C content in plasma.

  11. X-ray imaging for studying behavior of liquids at high pressures and high temperatures using Paris-Edinburgh press

    International Nuclear Information System (INIS)

    Several X-ray techniques for studying structure, elastic properties, viscosity, and immiscibility of liquids at high pressures have been integrated using a Paris-Edinburgh press at the 16-BM-B beamline of the Advanced Photon Source. Here, we report the development of X-ray imaging techniques suitable for studying behavior of liquids at high pressures and high temperatures. White X-ray radiography allows for imaging phase separation and immiscibility of melts at high pressures, identified not only by density contrast but also by phase contrast imaging in particular for low density contrast liquids such as silicate and carbonate melts. In addition, ultrafast X-ray imaging, at frame rates up to ∼105 frames/second (fps) in air and up to ∼104 fps in Paris-Edinburgh press, enables us to investigate dynamics of liquids at high pressures. Very low viscosities of melts similar to that of water can be reliably measured. These high-pressure X-ray imaging techniques provide useful tools for understanding behavior of liquids or melts at high pressures and high temperatures

  12. X-ray imaging for studying behavior of liquids at high pressures and high temperatures using Paris-Edinburgh press

    Energy Technology Data Exchange (ETDEWEB)

    Kono, Yoshio; Kenney-Benson, Curtis; Park, Changyong; Shen, Guoyin [HPCAT, Geophysical Laboratory, Carnegie Institution of Washington, 9700 S. Cass Ave., Argonne, Illinois 60439 (United States); Shibazaki, Yuki [Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Aramaki aza Aoba 6-3, Aoba-ku, Sendai 980-8578 (Japan); Wang, Yanbin [GeoSoilEnviroCARS, Center for Advanced Radiation Sources, The University of Chicago, 5640 S. Ellis Avenue, Chicago, Illinois 60637 (United States)

    2015-07-15

    Several X-ray techniques for studying structure, elastic properties, viscosity, and immiscibility of liquids at high pressures have been integrated using a Paris-Edinburgh press at the 16-BM-B beamline of the Advanced Photon Source. Here, we report the development of X-ray imaging techniques suitable for studying behavior of liquids at high pressures and high temperatures. White X-ray radiography allows for imaging phase separation and immiscibility of melts at high pressures, identified not only by density contrast but also by phase contrast imaging in particular for low density contrast liquids such as silicate and carbonate melts. In addition, ultrafast X-ray imaging, at frame rates up to ∼10{sup 5} frames/second (fps) in air and up to ∼10{sup 4} fps in Paris-Edinburgh press, enables us to investigate dynamics of liquids at high pressures. Very low viscosities of melts similar to that of water can be reliably measured. These high-pressure X-ray imaging techniques provide useful tools for understanding behavior of liquids or melts at high pressures and high temperatures.

  13. Preliminary validation of high performance liquid chromatography method for detection of methyl-testosterone residue in carp muscle

    Science.gov (United States)

    Jiang, Jie; Lin, Hong; Fu, Xiaoting; Li, Mingming

    2005-07-01

    The use of synthetic anabolic steroid methyltestosterone (MT) as growth promoter is prohibited in China. Validations of analytical methods for MT residue in food and the results obtained have become indispensable. The high performance liquid chromatography (HPLC) method for the detection of MT with liquid-liquid extraction by trichloromethane-methanol in carp muscle tissue was preliminarily validated with reference to the following parameters: recovery (accuracy) at the 1, 5 and l0 mgkg-1 level, between-run and within-run CV values (repeatability, also called relative standard deviation (RSD)) and limit of detection. The recoveries were above 80% and the between-run and within-run CV values below 10% for muscle tissue. The limit of detection was 0.05 mgkg-1.

  14. The multi-residue determination of coumarin-based anticoagulant rodenticides in animal materials by high-performance liquid chromatography.

    Science.gov (United States)

    Mundy, D E; Machin, A F

    1982-01-15

    The rodenticides brodifacoum, difenacoum, coumatetralyl and warfarin are determined in animal relicta by high-performance exclusion chromatography on porous silica. The first three compounds are not separated, but are subsequently differentiated by adsorption or reversed-phase high-performance liquid chromatography of the appropriate eluate fraction collected from the exclusion column. The method is rapid, and clean-up (on Sep-Pak silica cartridges) is simple. Mean recoveries from spiked substrates were generally above 80% at levels of 0.1-1.0 mg/kg. Routine limits of determination are about 0.05-0.1 mg/kg for warfarin and about 0.02 mg/kg for the other compounds. If analysis for warfarin is not required, the latter limit can be lowered to about 1 microgram/kg by a slight modification to the clean-up step. PMID:7056833

  15. Determination of some B Vitamins in Sour Cherry Juice Using Dispersive Liquid-liquid Microextraction Followed by High-performance Liquid Chromatography.

    Science.gov (United States)

    Parsaei, Parvin; Bahmaei, Manouchehr; Ghannadi, AliReza

    2014-01-01

    Dispersive liquid-liquid microextraction method (DLLME) combined with high-performance liquid chromatography-ultraviolet detection (HPLC-UV) was used to determine thiamine (B1), nicotinamide (B3) and pyridoxine (B6) in sour cherry juice. This method was rapid, simple and sensitive. Separation was accomplished using a C18 column. The optimum chromatographic conditions were found to be: mobile phase consisted of 8% methanol and 92% aqueous phase (1% (V/V) acetic acid water solution); flow rate, 0.7 mL/min; detection wavelength, 260 nm and pH, 3.3. The extraction efficiency of thiamine, nicotinamide and pyridoxine was influenced by factors such as: additional salt effect, the kind and volume of disperser and extraction solvents. In this research, the limit of detection (LOD) and quantification (LOQ) were 0.9 and 3 ng/mL for thiamine, 1.5 and 5 ng/mL for nicotinamide, 0.9 and 3 ng/mL for pyridoxine. The relative standard deviations (RSDs) were less than 2.87% (n=3). An appropriate linear behavior over the observed concentration range was obtained with the value of R²>0.996 for the target vitamins. This method was successfully applied to the sour cherry juice samples. Sour cherry var. Gise (Prunus cerasus var. Gise), which was used in this research, was a local variety of the sour cherry with large stone, double flowers, double fruits, dark red skin and dark red juice. This variety was identified in high altitude areas of Isfahan province after five years of study, since 2005, by Agricultural and Natural Resources Research Center of Isfahan. PMID:25587335

  16. High-Throughput Proteomics Using High Efficiency Multiple-Capillary Liquid Chromatography With On-Line High-Performance ESI FTICR Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Yufeng (BATTELLE (PACIFIC NW LAB)); Tolic, Nikola (BATTELLE (PACIFIC NW LAB)); Zhao, Rui (ASSOC WESTERN UNIVERSITY); Pasa Tolic, Ljiljana (BATTELLE (PACIFIC NW LAB)); Li, Lingjun (Illinois Univ Of-Urbana/Champa); Berger, Scott J.(ASSOC WESTERN UNIVERSITY); Harkewicz, Richard (BATTELLE (PACIFIC NW LAB)); Anderson, Gordon A.(BATTELLE (PACIFIC NW LAB)); Belov, Mikhail E.(BATTELLE (PACIFIC NW LAB)); Smith, Richard D.(BATTELLE (PACIFIC NW LAB))

    2000-12-01

    We report on the design and application of a high-efficiency multiple-capillary liquid chromatography (LC) system for high-throughput proteome analysis. The multiple-capillary LC system was operated at the pressure of 10,000 psi using commercial LC pumps to deliver the mobile phase and newly developed passive feedback valves to switch the mobile phase flow and introduce samples. The multiple-capillary LC system was composed of several serially connected dual-capillary column devices. The dual-capillary column approach was designed to eliminate the time delay for regeneration (or equilibrium) of the capillary column after its use under the mobile phase gradient condition (i.e. one capillary column was used in separation and the other was washed using mobile phase A). The serially connected dual-capillary columns and ESI sources were operated independently, and could be used for either''backup'' operation or with other mass spectrometer(s). This high-efficiency multiple-capillary LC system uses switching valves for all operations and is highly amenable to automation. The separations efficiency of dual-capillary column device, optimal capillary dimensions (column length and packed particle size), suitable mobile phases for electrospray, and the capillary re-generation were investigated. A high magnetic field (11.5 tesla) Fourier transform ion cyclotron resonance (FTICR) mass spectrometer was coupled on-line with this high-efficiency multiple-capillary LC system through an electrospray ionization source. The capillary LC provided a peak capacity of {approx}600, and the 2-D capillary LC-FTICR provided a combined resolving power of > 6 x 10 7 polypeptide isotopic distributions. For yeast cellular tryptic digests, > 100,000 polypeptides were typically detected, and {approx}1,000 proteins can be characterized in a single run.

  17. Determination of oxytetracycline in milk samples by polymer inclusion membrane separation coupled to high performance liquid chromatography.

    Science.gov (United States)

    Pérez-Silva, Irma; Rodríguez, José A; Ramírez-Silva, Ma Teresa; Páez-Hernández, Ma Elena

    2012-03-01

    The determination of oxytetracycline in milk samples using a polymer inclusion membrane concept with high performance liquid chromatography (HPLC) was studied. The membranes developed are composed by cellulose acetate as polymer base, Cyanex 923 as carrier and o-nitrophenyl octyl ether as plasticizer. In the optimal conditions, the method exhibits good linearity in the range 0.03-0.20 mg L(-1) with a limit of detection and quantification of 8.2 and 27.3 μg L(-1) respectively. The method was successfully applied to the analysis of milk samples with high selectivity.

  18. Recent Experimental Efforts on High-Pressure Supercritical Injection for Liquid Rockets and Their Implications

    Directory of Open Access Journals (Sweden)

    Bruce Chehroudi

    2012-01-01

    Full Text Available Pressure and temperature of the liquid rocket thrust chambers into which propellants are injected have been in an ascending trajectory to gain higher specific impulse. It is quite possible then that the thermodynamic condition into which liquid propellants are injected reaches or surpasses the critical point of one or more of the injected fluids. For example, in cryogenic hydrogen/oxygen liquid rocket engines, such as Space Shuttle Main Engine (SSME or Vulcain (Ariane 5, the injected liquid oxygen finds itself in a supercritical condition. Very little detailed information was available on the behavior of liquid jets under such a harsh environment nearly two decades ago. The author had the opportunity to be intimately involved in the evolutionary understanding of injection processes at the Air Force Research Laboratory (AFRL, spanning sub- to supercritical conditions during this period. The information included here attempts to present a coherent summary of experimental achievements pertinent to liquid rockets, focusing only on the injection of nonreacting cryogenic liquids into a high-pressure environment surpassing the critical point of at least one of the propellants. Moreover, some implications of the results acquired under such an environment are offered in the context of the liquid rocket combustion instability problem.

  19. Determination of methyldibromoglutaronitrile in cosmetic products by high performance liquid chromatography with electrochemical detection.

    Science.gov (United States)

    Rooselaar, J; Weyland, J W

    1993-02-01

    Synopsis A method for the determination of methyldibromoglutaronitrile in cosmetic products is described. Reversed phase high performance liquid chromatography and reductive electrochemical detection is employed to provide for improved selectivity and detectability compared to alternative methods. The method detects 0.002% methyldibromoglutaronitrile in cosmetic products and has a linear range from 0.006 up to 0.06%, which can easily be extended to the legally allowed limit of 0.1% by means of a simple dilution step. At a level of 0.03% the coefficient of variation was estimated to be 1.7%. Recoveries measured were between 98 and 100%. The method has been subjected to a ruggedness test, which indicated that it was stable, but slightly sensitive for a decrease in the detection potential. More than 130 cosmetic products have been analysed using the method. In 19 samples methyldibromoglutaronitrile was detected in concentrations varying between 0.002% and 0.030%. Résumé Une méthode a été mise au point pour la détermination du methyldibromoglutaronitrile, un conservateur cosmétique dont l'utilisation est croissante. La méthode utilise la chromatographie liquide à haute performance avec détection électrochimique pour permettre une amélioration de la détection et de la spécificité. Selon une procédure simple, le methyldibromoglutaronitrile est séparé sur une colonne 100 RP8 (lichosphere MERCK) avec une phase mobile constituee d'eau et d'acétone (60/40 v/v) avec un ajout de sulfate de sodium et du chlorure de sodium pour obtenir des concentrations de 0.02 M et 0.002 M respectivement. Une électrode en or a été utilisée pour la détection avec un potentiel de fonctionnement de -0.6 V réductif. Une détection par pulsation a été nécessaire pour obtenir une réponse stable. Le détecteur a été programmé pourgarder l'électrode pour 10 ms à 1 V, 10 ms à-1 V (réductif) et à-0.6 V pour 100 ms, ce potentiel a été utilisé comme mesure. Des

  20. SEPARATION OF CHOLESTEROL ESTERS BY SILVER ION CHROMATOGRAPHY USING HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY OR SOLID-PHASE EXTRACTION COLUMNS PACKED WITH A BONDED SULFONIC-ACID PHASE

    NARCIS (Netherlands)

    HOVING, EB; MUSKIET, FAJ; CHRISTIE, WW

    1991-01-01

    Two methods for the separation of cholesterol esters, based on the number of double bonds in their fatty acid moieties, are presented. Silver ion chromatography, usually performed on thin-layer chromatographic plates, was made suitable for high-performance liquid chromatography (HPLC) and solid-phas

  1. Gas-Liquid Mass Transfer in a Slurry Bubble Column Reactor under High Temperature andHigh Pressure

    Institute of Scientific and Technical Information of China (English)

    杨卫国; 王金福; 金涌

    2001-01-01

    The gas-liquid mass transfer of H2 and CO in a high temperature and high-pressure three-phase slurry bubble column reactor is studied. The gas-liquid volumetric mass transfer coefficients kLa are obtained by measuring the dissolution rate of H2 and CO. The influences of the main operation conditions, such as temperature, pressure,superficial gas velocity and solid concentration, are studied systematically. Two empirical correlations are proposed to predict kLa values for H2 and CO in liquid paraffln/solid particles slurry bubble column reactors.

  2. ANALYSES OF QUINOLONE ANTIMICROBIALS IN HUMAN PLASMA BY CAPILLARY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY/FAST ATOM BOMBARDMENT MASS SPECTROMETRY

    OpenAIRE

    Hattori, Hideki; Suzuki, Osamu; Seno, Hiroshi; Ishii, Akira; Yamada, Takamichi

    1993-01-01

    Capillary high-performance liquid chromatography (HPLC) was combined with frit fast atom bombardment (FAB)-mass spectrometry (MS) , and a detailed procedure has been established for on-line analysis of ten quinolone antimicrobials in human plasma by the HPLC/FAB-MS. A special column switching device for concentration enabled injection of as large as a 500 μl sample; and the capillary column (0.5 mm i. d.) enabled introduction of its entire effluent to the frit interface of FAB-MS. These condi...

  3. Determination of conjugated bile acids in human bile and duodenal fluid by reverse-phase high-performance liquid chromatography.

    Science.gov (United States)

    Bloch, C A; Watkins, J B

    1978-05-01

    A simple mehtod using reverse-phase liquid chromatography is presented for resolution and quantitation of the major conjugated bile acids of man, including the glycine and taurine conjugates of the dihydroxy bile acids, chenodeoxycholic and deoxycholic acid. Using modern, high-performance chromatographic equipment, analysis time is less than 30 minutes. The quantitative range of the method, with detection by refractive index, is 0.05 to 0.1 mumol of bile acid and the limit of detection for an injection sample is 0.01 mumol. This provides a sensitivity sufficient for analysis of dilute duodenal and gallbladder bile with minimal sample preparation.

  4. Synthesis of novel glucose-based polymers and their applications as chiral stationary phases for high performance liquid chromatography

    Institute of Scientific and Technical Information of China (English)

    Tomoyuki IKAI; Takayuki YAMADA

    2016-01-01

    Two novel polymers containing glucose units as the main-chain that only differ in terms of their regioregularity were synthesized to evaluate their chiral recognition abilities as chiral stationary phases( CSPs) for high performance liquid chromatography( HPLC). The regioregular polymer( poly-5)shows clear resolution ability for the racemate of cobalt(Ⅲ)acetylacetonate( Co( acac)3 ),whereas the corresponding regioirregular polymer(poly-3)does not show any chiral recognition for Co(acac)3. The regioregular polymer main-chain seems to play an important role not only in providing an efficient interaction with the racemate but also in expressing the chiral recognition ability as a CSP for HPLC.

  5. Determination of 2-naphthylamine in urine by a novel reversed-phase high-performance liquid chromatography method

    DEFF Research Database (Denmark)

    Hansen, Åse Marie; Poulsen, O M; Christensen, J M;

    1992-01-01

    A high-performance liquid chromatographic method for the determination of 2-naphthylamine in urine using fluorescence detection was developed. The method validation analysis showed the method to be in analytical control, i.e. the distribution of the difference between the observed and true values...... of the method evaluation samples did not deviate significantly from the normal distribution. The recovery of the method was 85%. The entire run time of chromatography was 10 min using isocratic elution (acetonitrile-water, 35:65), and the retention time for 2-naphthylamine was 5.8 min. The relative short time...

  6. Postcolumn derivatization method for determination of reducing and phosphorylated sugars in chicken by high performance liquid chromatography.

    Science.gov (United States)

    Aliani, Michel; Farmer, Linda J

    2002-05-01

    A postcolumn derivatization method is described for determination of reducing sugars and phosphorylated reducing sugars from chicken meat and other foods using high-performance liquid chromatography (HPLC). Reducing sugars are extracted with ethanol/water, separated on a Kromasil amine-bonded column by isocratic analysis using acetonitrile/water as the mobile phase, and, after postcolumn reaction with tetrazolium blue, are determined by the resulting absorbance at 550 nm. Phosphorylated sugars are first dephosphorylated using alkaline phosphatase and then determined by the same method. PMID:11982395

  7. Investigation into the temporal stability of aqueous standard solutions of psilocin and psilocybin using high performance liquid chromatography.

    Science.gov (United States)

    Anastos, N; Barnett, N W; Pfeffer, F M; Lewis, S W

    2006-01-01

    This paper reports an investigation into the temporal stability of aqueous solutions of psilocin and psilocybin reference drug standards over a period of fourteen days. This study was performed using high performance liquid chromatography utilising a (95:5% v/v) methanol: 10 mM ammonium formate, pH 3.5 mobile phase and absorption detection at 269 nm. It was found that the exclusion of light significantly prolonged the useful life of standards, with aqueous solutions of both psilocin and psilocybin being stable over a period of seven days.

  8. Quantification of six bioactive compounds in Zhenqi Fuzheng preparation by high-performance liquid chromatography couple

    Institute of Scientific and Technical Information of China (English)

    Yi-Kai Shi; Fang Cui; Fang-Di Hu; Ying-Yan Bi; Yu-Feng Ma; Shi-Lan Feng

    2011-01-01

    A simple and accurate high-performance liquid chromatography(HPLC)coupled with diode array detector(DAD)and evaporative light scattering detector(ELSD)was established for the determination of six bioactive compounds in Zhenqi Fuzheng preparation(ZFP).The

  9. Expansion characteristics of twin combustion gas jets with high pressure in cylindrical filling liquid chamber

    Institute of Scientific and Technical Information of China (English)

    薛晓春; 余永刚; 张琦

    2013-01-01

    To deal with the problem of how to control the interior ballistic stability in the bulk-loaded liquid propellant gun, the expansion and mixing process of the twin combustion-gas jets with high temperature and pressure in a liquid medium is studied in the cylindrical filling liquid chamber. A series of the jet expansion shapes is obtained by using a high-speed photographic system. The influences of the jet pressure on the jet expansion shape are discussed. Based on the experiments, the three-dimensional mathematical model is established. The expansion processes of the twin gas jets in the liquid medium are simulated by means of fluent to get the pressure, density, temperature, velocity contours and evolutionary process of vortices. Results show that the jet external outline and tops are all irregular. The Kelvin-Helmholtz instability is shown in the whole expansion process. The numerical simulation results of the axial displacement of the twin gas jets in liquid agree well with the experiment.

  10. Ultra-high-performance liquid chromatography-Time-of-flight high resolution mass spectrometry to quantify acidic drugs in wastewater.

    Science.gov (United States)

    Becerra-Herrera, Mercedes; Honda, Luis; Richter, Pablo

    2015-12-01

    A novel analytical approach involving an improved rotating-disk sorptive extraction (RDSE) procedure and ultra-high-performance liquid chromatography (UHPLC) coupled to an ultraspray electrospray ionization source (UESI) and time-of-flight mass spectrometry (TOF/MS), in trap mode, was developed to identify and quantify four non-steroidal anti-inflammatory drugs (NSAIDs) (naproxen, ibuprofen, ketoprofen and diclofenac) and two anti-cholesterol drugs (ACDs) (clofibric acid and gemfibrozil) that are widely used and typically found in water samples. The method reduced the amount of both sample and reagents used and also the time required for the whole analysis, resulting in a reliable and green analytical strategy. The analytical eco-scale was calculated, showing that this methodology is an excellent green analysis, increasing its ecological worth. The detection limits (LOD) and precision (%RSD) were lower than 90ng/L and 10%, respectively. Matrix effects and recoveries were studied using samples from the influent of a wastewater treatment plant (WWTP). All the compounds exhibited suppression of their signals due to matrix effects, and the recoveries were approximately 100%. The applicability and reliability of this methodology were confirmed through the analysis of influent and effluent samples from a WWTP in Santiago, Chile, obtaining concentrations ranging from 1.1 to 20.5μg/L and from 0.5 to 8.6μg/L, respectively. PMID:26559617

  11. In situ crystallization of ionic liquid [Emim][PF6] from methanol solution under high pressure.

    Science.gov (United States)

    Li, Haining; Su, Lei; Zhu, Xiang; Cheng, Xuerui; Yang, Kun; Yang, Guoqiang

    2014-07-24

    The solubility of 1-ethyl-3-methylimidazolium hexafluorophosphate ([Emim][PF6]) in methanol under high pressure is newly measured quantitatively according to the correlation between the ratios of Raman intensity and the concentrations. In situ crystallization and cation conformation of [Emim][PF6] from methanol solution under high pressure have been investigated by using Raman spectroscopy in detail. Remarkably, crystal polymorphism was observed and two crystalline phases (phases I and II) coexisted under high pressure up to ∼ 1.4 GPa. However, only phase II was obtained by recrystallization at ∼ 2 GPa. Our findings may facilitate the development of an effective way for crystallization and purification of ionic liquids under high pressure.

  12. Peptide profiling of Internet-obtained Cerebrolysin using high performance liquid chromatography - electrospray ionization ion trap and ultra high performance liquid chromatography - ion mobility - quadrupole time of flight mass spectrometry.

    Science.gov (United States)

    Gevaert, Bert; D'Hondt, Matthias; Bracke, Nathalie; Yao, Han; Wynendaele, Evelien; Vissers, Johannes Petrus Cornelis; De Cecco, Martin; Claereboudt, Jan; De Spiegeleer, Bart

    2015-09-01

    Cerebrolysin, a parenteral peptide preparation produced by controlled digestion of porcine brain proteins, is an approved nootropic medicine in some countries. However, it is also easily and globally available on the Internet. Nevertheless, until now, its exact chemical composition was unknown. Using high performance liquid chromatography (HPLC) coupled to ion trap and ultra high performance liquid chromatography (UHPLC) coupled to quadrupole-ion mobility-time-of-flight mass spectrometry (Q-IM-TOF MS), combined with UniProt pig protein database search and PEAKS de novo sequencing, we identified 638 unique peptides in an Internet-obtained Cerebrolysin sample. The main components in this sample originate from tubulin alpha- and beta-chain, actin, and myelin basic protein. No fragments of known neurotrophic factors like glial cell-derived neurotrophic factor (GDNF), neurotrophin nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and ciliary neurotrophic factor (CNTF) were found, suggesting that the activities reported in the literature are likely the result of new, hitherto unknown cryptic peptides with nootropic properties. PMID:26017115

  13. Methods of analysis by the U.S. Geological Survey Organic Geochemistry Research Group; determination of chloroacetanilide herbicide metabolites in water using high-performance liquid chromatography-diode array detection and high-performance liquid chromatography/mass spectrometry

    Science.gov (United States)

    Zimmerman, L.R.; Hostetler, K.A.; Thurman, E.M.

    2000-01-01

    Analytical methods using high-performance liquid chromatography-diode array detection (HPLC-DAD) and high-performance liquid chromatography/mass spectrometry (HPLC/MS) were developed for the analysis of the following chloroacetanilide herbicide metabolites in water: acetochlor ethanesulfonic acid (ESA), acetochlor oxanilic acid (OXA), alachlor ESA, alachlor OXA, metolachlor ESA, and metolachlor OXA. Good precision and accuracy were demonstrated for both the HPLC-DAD and HPLC/MS methods in reagent water, surface water, and ground water. The mean HPLC-DAD recoveries of the chloroacetanilide herbicide metabolites from water samples spiked at 0.25, 0.50, and 2.0 mg/L (micrograms per liter) ranged from 84 to 112 percent, with relative standard deviations of 18 percent or less. The mean HPLC/MS recoveries of the metabolites from water samples spiked at 0.05, 0.20, and 2.0 mg/L ranged from 81 to 125 percent, with relative standard deviations of 20 percent or less. The limit of quantitation (LOQ) for all metabolites using the HPLC-DAD method was 0.20 mg/L, whereas the LOQ using the HPLC/MS method was 0.05 mg/L. These metabolite-determination methods are valuable for acquiring information about water quality and the fate and transport of the parent chloroacetanilide herbicides in water.

  14. Peptide profiling of Internet-obtained Cerebrolysin using high performance liquid chromatography - electrospray ionization ion trap and ultra high performance liquid chromatography - ion mobility - quadrupole time of flight mass spectrometry.

    Science.gov (United States)

    Gevaert, Bert; D'Hondt, Matthias; Bracke, Nathalie; Yao, Han; Wynendaele, Evelien; Vissers, Johannes Petrus Cornelis; De Cecco, Martin; Claereboudt, Jan; De Spiegeleer, Bart

    2015-09-01

    Cerebrolysin, a parenteral peptide preparation produced by controlled digestion of porcine brain proteins, is an approved nootropic medicine in some countries. However, it is also easily and globally available on the Internet. Nevertheless, until now, its exact chemical composition was unknown. Using high performance liquid chromatography (HPLC) coupled to ion trap and ultra high performance liquid chromatography (UHPLC) coupled to quadrupole-ion mobility-time-of-flight mass spectrometry (Q-IM-TOF MS), combined with UniProt pig protein database search and PEAKS de novo sequencing, we identified 638 unique peptides in an Internet-obtained Cerebrolysin sample. The main components in this sample originate from tubulin alpha- and beta-chain, actin, and myelin basic protein. No fragments of known neurotrophic factors like glial cell-derived neurotrophic factor (GDNF), neurotrophin nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and ciliary neurotrophic factor (CNTF) were found, suggesting that the activities reported in the literature are likely the result of new, hitherto unknown cryptic peptides with nootropic properties.

  15. Stability and Degradation of Caffeoylquinic Acids under Different Storage Conditions Studied by High-Performance Liquid Chromatography with Photo Diode Array Detection and High-Performance Liquid Chromatography with Electrospray Ionization Collision-Induced Dissociation Tandem Mass Spectrometry.

    Science.gov (United States)

    Xue, Meng; Shi, Hang; Zhang, Jiao; Liu, Qing-Quan; Guan, Jun; Zhang, Jia-Yu; Ma, Qun

    2016-01-01

    Caffeoylquinic acids (CQAs) are main constituents in many herbal medicines with various biological and pharmacological effects. However, CQAs will degrade or isomerize when affected by temperature, pH, light, etc. In this study, high-performance liquid chromatography with photodiode array detection (HPLC-PDA) and high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) was utilized to study the stability and degradation of CQAs (three mono-acyl CQAs and four di-acyl CQAs) under various ordinary storage conditions (involving different temperatures, solvents, and light irradiation). The results indicated that the stability of CQAs was mainly affected by temperature and light irradiation, while solvents did not affect it in any obvious way under the conditions studied. Mono-acyl CQAs were generally much more stable than di-acyl CQAs under the same conditions. Meanwhile, the chemical structures of 30 degradation products were also characterized by HPLC-MS(n), inferring that isomerization, methylation, and hydrolysis were three major degradation pathways. The result provides a meaningful clue for the storage conditions of CQAs standard substances and samples. PMID:27455213

  16. Stability and Degradation of Caffeoylquinic Acids under Different Storage Conditions Studied by High-Performance Liquid Chromatography with Photo Diode Array Detection and High-Performance Liquid Chromatography with Electrospray Ionization Collision-Induced Dissociation Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Meng Xue

    2016-07-01

    Full Text Available Caffeoylquinic acids (CQAs are main constituents in many herbal medicines with various biological and pharmacological effects. However, CQAs will degrade or isomerize when affected by temperature, pH, light, etc. In this study, high-performance liquid chromatography with photodiode array detection (HPLC-PDA and high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS was utilized to study the stability and degradation of CQAs (three mono-acyl CQAs and four di-acyl CQAs under various ordinary storage conditions (involving different temperatures, solvents, and light irradiation. The results indicated that the stability of CQAs was mainly affected by temperature and light irradiation, while solvents did not affect it in any obvious way under the conditions studied. Mono-acyl CQAs were generally much more stable than di-acyl CQAs under the same conditions. Meanwhile, the chemical structures of 30 degradation products were also characterized by HPLC-MSn, inferring that isomerization, methylation, and hydrolysis were three major degradation pathways. The result provides a meaningful clue for the storage conditions of CQAs standard substances and samples.

  17. Development and validation of ultra-high performance supercritical fluid chromatography method for determination of illegal dyes and comparison to ultra-high performance liquid chromatography method.

    Science.gov (United States)

    Khalikova, Maria A; Šatínský, Dalibor; Solich, Petr; Nováková, Lucie

    2015-05-18

    A novel simple, fast and efficient ultra-high performance supercritical fluid chromatography (UHPSFC) method was developed and validated for the separation and quantitative determination of eleven illegal dyes in chili-containing spices. The method involved a simple ultrasound-assisted liquid extraction of illegal compounds with tetrahydrofuran. The separation was performed using a supercritical fluid chromatography system and CSH Fluoro-Phenyl stationary phase at 70°C. The mobile phase was carbon dioxide and the mixture of methanol:acetonitrile (1:1, v/v) with 2.5% formic acid as an additive at the flow rate 2.0 mL min(-1). The UV-vis detection was accomplished at 500 nm for seven compounds and at 420 nm for Sudan Orange G, Butter Yellow, Fast Garnet GBC and Methyl Red due to their maximum of absorbance. All eleven compounds were separated in less than 5 min. The method was successfully validated and applied using three commercial samples of chili-containing spices - Chili sauce (Indonesia), Feferony sauce (Slovakia) and Mojo sauce (Spain). The linearity range of proposed method was 0.50-9.09 mg kg(-1) (r ≥ 0.995). The detection limits were determined as signal to noise ratio of 3 and were ranged from 0.15 mg kg(-1) to 0.60 mg kg(-1) (1.80 mg kg(-1) for Fast Garnet) for standard solution and from 0.25 mg kg(-1) to 1.00 mg kg(-1) (2.50 mg kg(-1) for Fast Garnet, 1.50 mg kg(-1) for Sudan Red 7B) for chili-containing samples. The recovery values were in the range of 73.5-107.2% and relative standard deviation ranging from 0.1% to 8.2% for within-day precision and from 0.5% to 8.8% for between-day precision. The method showed potential for being used to monitor forbidden dyes in food constituents. The developed UHPSFC method was compared to the UHPLC-UV method. The orthogonality of Sudan dyes separation by these two methods was demonstrated. Benefits and drawbacks were discussed showing the reliability of both methods for monitoring of studied illegal dyes in real

  18. High catechin concentrations detected in Withania somnifera (ashwagandha by high performance liquid chromatography analysis

    Directory of Open Access Journals (Sweden)

    Sulaiman Siti

    2011-08-01

    Full Text Available Abstract Background Withania somnifera is an important medicinal plant traditionally used in the treatment of many diseases. The present study was carried out to characterize the phenolic acids, flavonoids and 1,1-diphenyl-2-picrylhydrazyl radical (DPPH scavenging activities in methanolic extracts of W. somnifera fruits, roots and leaves (WSFEt, WSREt and WSLEt. Methods WSFEt, WSREt and WSLEt was prepared by using 80% aqueous methanol and total polyphenols, flavonoids as well as DPPH radical scavenging activities were determined by spectrophotometric methods and phenolic acid profiles were determined by HPLC methods. Results High concentrations of both phenolics and flavonoids were detected in all parts of the plant with the former ranging between 17.80 ± 5.80 and 32.58 ± 3.16 mg/g (dry weight and the latter ranging between 15.49 ± 1.02 and 31.58 ± 5.07 mg/g. All of the three different plant parts showed strong DPPH radical scavenging activities (59.16 ± 1.20 to 91.84 ± 0.38%. Eight polyphenols (gallic, syringic, benzoic, p-coumaric and vanillic acids as well as catechin, kaempferol and naringenin have been identified by HPLC in parts of the plant as well. Among all the polyphenols, catechin was detected in the highest concentration (13.01 ± 8.93 to 30.61 ± 11.41 mg/g. Conclusion The results indicating that W. somnifera is a plant with strong therapeutic properties thus further supporting its traditional claims. All major parts of W. somnifera such as the roots, fruits and leaves provide potential benefits for human health because of its high content of polyphenols and antioxidant activities with the leaves containing the highest amounts of polyphenols specially catechin with strong antioxidant properties.

  19. Hazards of Secondary Bromadiolone Intoxications Evaluated using High-performance Liquid Chromatography with Electrochemical Detection

    Directory of Open Access Journals (Sweden)

    René Kizek

    2007-07-01

    Full Text Available This study reported on the possibility of intoxications of non-target wild animalsassociated with use of bromadiolone as the active component of rodenticides withanticoagulation effects. A laboratory test was done with earthworms were exposed tobromadiolone-containing granules under the conditions specified in the modified OECD207 guideline. No mortality of earthworms was observed during the fourteen days longexposure. When the earthworms from the above test became a part of the diet of commonvoles in the following experiment, no mortality of consumers was observed too. However,electrochemical analysis revealed higher levels of bromadiolone in tissues fromearthworms as well as common voles compared to control animals. There were determinedcomparable levels of bromadiolone in the liver tissue of common voles after primary(2.34±0.10 μg/g and secondary (2.20±0.53 μg/g intoxication. Therefore, the risk ofsecondary intoxication of small mammalian species feeding on bromadiolone-containing earthworms is the same as of primary intoxication through baited granules. Bromadiolone bio-accumulation in the food chain was monitored using the newly developed analytical procedure based on the use of a liquid chromatography coupled with electrochemical detector (HPLC-ED. The HPLC-ED method allowed to determine the levels of bromadiolone in biological samples and is therefore suitable for examining the environmental hazards of this substance.

  20. Ionic Liquid-based Microwave-assisted Liquid-liquid Microextraction and High Performance Liquid Chromatography Determination of Sulfonamides from Animal Oils

    Institute of Scientific and Technical Information of China (English)

    FENG Xu-dong; LIANG Fang-hui; SU Rui; WU Li-jie; LI Xue-yuan; WANG Xing-hua; ZHANG Han-qi

    2013-01-01

    The authors performed ionic liquid-based microwave-assisted liquid-liquid microextraction(IL-based MALLME) coupled with high performance liquid chromatographic separation for the determination of 6 sulfonamides (SAs) from animal oils.The target analytes were extracted from animal oil samples with sodium hydroxide solution containing 1-butyl-3-methylimidazolium tetrafluoroborateand as the extraction solvent under microwave irradiation.The experimental parameters of the IL-based MALLME,including types of ILs,volume of IL,amount of ion-pairing agent(NH4PF6),pH value of sample solution,and extraction temperature and time were evaluated.The limits of detection and quantification obtained were in a range of 0.4-0.5 μg/kg and a range of 1.2-1.8 μg/kg,respectively.The accuracy of the method was evaluated by analyzing five spiked animal oil samples at two fortified levels(5 and 50 μg/kg),and the recoveries of SAs varied from 81.4% to 114.5% with relative standard deviations ranging from 0.8% to 9.0%.

  1. Stability-indicating High-performance Liquid Chromatography Method for Simultaneous Determination of Aminophylline and Chlorpheniramine Maleate in Pharmaceutical Formulations.

    Science.gov (United States)

    Ali, A; Ahmed, M; Mahmud, T; Qadir, M A; Nadeem, K; Saleem, A

    2015-01-01

    The present work deals with the development and validation of method for simultaneous determination of antihistaminic drugs in pharmaceutical formulations. A precise, specific and accurate reverse phase-high-performance liquid chromatography method for the simultaneous measurement of aminophylline and chlorpheniramine maleate was developed. The separation of drugs was achieved on C-18 (5 μm, 250×4.6 mm) high-performance liquid chromatography column. The runtime for analysis was 10 min. Mobile phase is mixture containing dilute H2SO4:methanol (60:40% v/v) with flow rate adjusted at 1.5 ml/min. The detection of components was performed at a wavelength of 264 nm. Retention times of aminophylline and chlorphinramine maleate were found to be 2.00 and 3.25 min, respectively. Linearity was found in the range of 16-24 μg/ml for chlorpheniramine maleate and 102.4-153.6 μg/ml for aminophylline with a correlation coefficient of 0.9998 and 0.9996, respectively. High peak purity index of 99.99% indicated the complete separation of analytes in the presence of degradation products is justification of method stability. Linearity, accuracy, specificity, precision and robustness studies were performed for method validation. PMID:26798164

  2. [Simultaneous determination of inhibitive components in anti-acne cosmetics by reversed-phase high performance liquid chromatography].

    Science.gov (United States)

    Wu, Ting; Wang, Chao; Li, Nan

    2006-11-01

    The inhibitive components in anti-acne cosmetics including spironolactone, benzoyl peroxide, and tretinoin were simultaneously determined by reversed-phase high performance liquid chromatography (RP-HPLC). The cosmetics were extracted with methanol by microwave and analyzed by high performance liquid chromatography. The HPLC conditions were as follows: Kromasil C18 column (4.6 mm i. d. x 250 mm, 5 microm), methanol and phosphate buffer as mobile phase with gradient elution at a flow rate of 1.0 mL/min, UV detection at 265 nm. Three components were separated completely within 11 min. The calibration curves of the three compounds were linear (nu > 0.999 9) between 1 and 200 mg/L. The average recoveries were from 88.2% to 106.7% with relative standard deviations lower than 3. 1%. The detection limits (S/N = 3) were 0.101 mmicrog for spironolactone, 0.100 microg for benzoyl peroxide, and 0. 107 microg for tretinoin. The method is simple and rapid with high accuracy, and suitable for the determination of the 3 inhibitive components in anti-acne cosmetics. PMID:17288140

  3. High performance liquid chromatography coupled with resonance Rayleigh scattering for the detection of three fluoroquinolones and mechanism study

    Science.gov (United States)

    Zhou, Mingqiong; Peng, Jingdong; He, Rongxing; He, Yuting; Zhang, Jing; Li, Aiping

    2015-02-01

    A reliable and versatile high performance liquid chromatography coupled with resonance Rayleigh scattering method was established for the determination of three fluoroquinolones, including levofloxacin, norfloxacin and enrofloxacin in water sample and human urine sample. In pH 4.4-4.6 Britton-Robinson buffer medium, the fluoroquinolones separated by high performance liquid chromatography could react with erythrosine to form 1:1 ion-association complexes, which could make contributions to the great enhancement of RRS. The resonance Rayleigh scattering signal was recorded at λex = λem = 330 nm. The resonance Rayleigh scattering spectral characteristics of the drugs and the experimental conditions such as pH, detection wavelength, erythrosine concentration, flow rate, the length of reaction tube were studied. Quantum chemistry calculation, Fourier transform infrared spectroscopy and absorption spectroscopy were used to discuss the reaction mechanism. The recoveries of samples added standard ranged from 97.53% to 102.00%, and the relative standard deviation was below 4.64%. The limit of detection (S/N = 3) of 0.05-0.12 μg mL-1 was reached, and the linear regression coefficients were all above 0.999. The proposed method was proved as a simple, low cost and high sensitivity method.

  4. Determination of total phthalates in edible oils by high-performance liquid chromatography coupled with photodiode array detection.

    Science.gov (United States)

    Xie, Qilong; Sun, Dekui; Han, Yangying; Jia, Litao; Hou, Bo; Liu, Shuhui; Li, Debao

    2016-03-01

    The previously reported procedure for the determination of the total phthalate in fatty food involved the extraction of phthalates using chloroform/methanol followed by the removal of the solvents before alkaline hydrolysis requiring 20 h and derivatization of phthalic acid. In this study, a phase-transfer catalyst (tetrabutylammonium chloride) was used in the liquid-liquid heterogeneous hydrolysis of phthalates in oil matrix shortening the reaction time to within 25 min. The resulting phthalic acid in the hydrolysate was extracted by a novel molecular complex based dispersive liquid-liquid microextraction method coupled with back-extraction before high-performance liquid chromatography coupled with photodiode array detection. Under the optimal experimental conditions, the linearity of the method was in the range of 0.5-12 nmol/g with the correlation coefficients (r) >0.997. The detection limit (S/N = 3) was 0.11 nmol/g. Intraday and interday repeatability values expressed as relative standard deviation were 3.9 and 7.1%, respectively. The recovery rates ranged from 82.4 to 99.0%. The developed method was successfully applied for the analysis of total phthalate in seven edible oils.

  5. Design and implementation of an automated liquid-phase microextraction-chip system coupled on-line with high performance liquid chromatography

    DEFF Research Database (Denmark)

    Li, Bin; Petersen, Nickolaj J.; Payán, María D Ramos;

    2014-01-01

    An automated liquid-phase microextraction (LPME) device in a chip format has been developed and coupled directly to high performance liquid chromatography (HPLC). A 10-port 2-position switching valve was used to hyphenate the LPME-chip with the HPLC autosampler, and to collect the extracted....... The composition of the supported liquid membrane (SLM) and carrier was optimized in order to achieve reasonable extraction performance of all the five alkaloids. With 1-octanol as SLM solvent and with 25mM sodium octanoate as anionic carrier, extraction recoveries for the different opium alkaloids ranged between...... analytes, which then were delivered to the HPLC column. The LPME-chip-HPLC system was completely automated and controlled by the software of the HPLC instrument. The performance of this system was demonstrated with five alkaloids i.e. morphine, codeine, thebaine, papaverine, and noscapine as model analytes...

  6. One-pot preparation of a novel monolith for high performance liquid chromatography applications.

    Science.gov (United States)

    Jiao, Xiaoyan; Shen, Shigang; Shi, Tiesheng

    2015-12-15

    Various novel porous organic-based monoliths with the mode of hydrophobicity were synthesized by in situ free-radical crosslinking copolymerization and optimized for the separations of small molecules and high-performance reversed-phase chromatography (RP-chromatography). These monoliths contained co-polymers based on glycidyl methacrylate (GMA)/ethylene glycol dimethacrylate (EDMA)/tripropylene glycol diacrylate (TPGDA) or EDMA/TPGDA. A mixture of cetanol, methanol and poly (ethylene glycol) (PEG) was used as the porogen, with the ratio of these solvents being varied along with the polymerization temperature to generate a library of monoliths. The conditions were optimized and the resulting poly (GMA-co-TPGDA-co-EDMA) monolith was investigated by infrared spectrometer (IR), field emission scanning electron microscope (FESEM), and mercury intrusion porosimetry (MIP), respectively. The column performance was assessed by the separation of a series of neutral solutes of benzene derivatives. The result demonstrated that the prepared monolith exhibited an RP-chromatographic behavior and relatively homogeneous structure, good permeability and separation performance. Moreover, the relative standard deviations (RSDs) of the retention factor values for benzene derivatives were less than 1.5% (n=7, column-to-column). The approach used in this study was extended to the separation of anilines.

  7. Melatonin in edible plants identified by radioimmunoassay and by high performance liquid chromatography-mass spectrometry

    International Nuclear Information System (INIS)

    Melatonin, the chief hormone of the pineal gland in vertebrates, is widely distributed in the animal kingdom. Among many functions, melatonin synchronizes circadian and circannual rhythms, stimulates immune function, may increase life span, inhibits growth of cancer cells in vitro and cancer progression and promotion in vivo, and was recently shown to be a potent hydroxyl radical scavenger and antioxidant. Hydroxyl radicals are highly toxic by-products of oxygen metabolism that damage cellular DNA and other macromolecules. Herein we report that melatonin, in varying concentrations, is also found in a variety of plants. Melatonin concentrations, measured in nine different plants by radioimmunoassay, ranged from 0 to 862 pg melatonin/mg protein. The presence of melatonin was verified by gas chromatography/mass spectrometry. Our findings suggest that the consumption of plant materials that contain high levels of melatonin could alter blood melatonin levels of the indole as well as provide protection of macromolecules against oxidative damage. (au) 30 refs

  8. Melatonin in edible plants identified by radioimmunoassay and by high performance liquid chromatography-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Dubbels, R.; Klenke, E.; Schnakenberg, E.; Ehlers, C.; Schloot, W. [Univ. of Bremen, Center of Human Genetics and Genetic Counselling, Bremen (Germany); Reiter, R.J. [The Univ. of Texas Health Science Center at San Antonio, Dept. of Cellular and Structural Biology, San Antonio, Texas (United States); Goebel, A.; Schiware, H.W. [Gemeinschaftslabor Dr. Schiwara et al., Breman (Germany)

    1995-01-01

    Melatonin, the chief hormone of the pineal gland in vertebrates, is widely distributed in the animal kingdom. Among many functions, melatonin synchronizes circadian and circannual rhythms, stimulates immune function, may increase life span, inhibits growth of cancer cells in vitro and cancer progression and promotion in vivo, and was recently shown to be a potent hydroxyl radical scavenger and antioxidant. Hydroxyl radicals are highly toxic by-products of oxygen metabolism that damage cellular DNA and other macromolecules. Herein we report that melatonin, in varying concentrations, is also found in a variety of plants. Melatonin concentrations, measured in nine different plants by radioimmunoassay, ranged from 0 to 862 pg melatonin/mg protein. The presence of melatonin was verified by gas chromatography/mass spectrometry. Our findings suggest that the consumption of plant materials that contain high levels of melatonin could alter blood melatonin levels of the indole as well as provide protection of macromolecules against oxidative damage. (au) 30 refs.

  9. Rapid screening for drugs of abuse in biological fluids by ultra high performance liquid chromatography/Orbitrap mass spectrometry.

    Science.gov (United States)

    Jagerdeo, Eshwar; Schaff, Jason E

    2016-08-01

    We present a UPLC(®)-High Resolution Mass Spectrometric method to simultaneously screen for nineteen benzodiazepines, twelve opiates, cocaine and three metabolites, and three "Z-drug" hypnotic sedatives in both blood and urine specimens. Sample processing consists of a high-speed, high-temperature enzymatic hydrolysis for urine samples followed by a rapid supported liquid extraction (SLE). The combination of ultra-high resolution chromatography with high resolution mass spectrometry allows all 38 analytes to be uniquely detected with a ten minute analytical run. Limits of detection for all target analytes are 3ng/mL or better, with only 0.3mL of specimen used for analysis. The combination of low sample volume with fast processing and analysis makes this method a suitable replacement for immunoassay screening of the targeted drug classes, while providing far superior specificity and better limits of detection than can routinely be obtained by immunoassay. PMID:27236533

  10. Determination of Polysaccharide in Radix pseudostellariae Extract by Size-Exclusion High-Performance Liquid Chromatography

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A simple size-exclusion high-performance liquid chromatographic method was developed for rapid molecular mass screening to determine the average molecular mass, polydispersity, and quantity of Taizishen polysaccharides extract. The screening used a TOSOH TSK-GEL G3000SW high-performance liquid chromatographic column with 0.1 mol/L NaNO3 buffer as the mobile phase and refractive index detector. The molecular mass calibration curve was linear for polysaccharide standards from 10 to 100 kDa with a correlation coefficient of 0.9991. The method can be used to analyze the quantity, average molecular mass,and polydispersity of polysaccharides. In addition, the screening method is suitable for quality control of polysaccharide preparations in Chinese medicines and pharmaceutical products.

  11. Determination of pentachlorophenol in water and aquifer sediments by high-performance liquid chromatography

    Science.gov (United States)

    Goerlitz, D.F.

    1981-01-01

    Methods for the determination of pentachlorophenol (PCP) in water and aquifer sediments are presented. Reverse-phase high-performance liquid chromotography employing ion suppression and gradient elution is used. PCP can be determined directly in water at a lower limit of detection Of 0.2 micrograms per liter. For extracts of sediment, PCP can be determined to a lower limit of 1.0 micrograms per kilogram.

  12. Quantitative Estimation of Andrographolide by Reverse Phase-High Liquid Chromatography Method from Andrographis Paniculata Nees.

    OpenAIRE

    Dilip Bhaskar Jadhao

    2012-01-01

    Abstract:Reverse Phase High performance liquid chromatographic method with UV array detection was established for the determination of Andrographolide. The Andrographolide was separated using isocratic solvent system consisting of isopropyl alcohol, formic acid and water (70:10:20 v/v) at flow rate of 1.0 ml/min and the detection wavelength of 223 nm. The method was validated for linearity, precision, accuracy, limit of detection (LOD), and limit of quantitation (LOQ). The linearity of the pr...

  13. High-performance liquid chromatography with fluorescence detection for the rapid analysis of pheophytins and pyropheophytins in virgin olive oil.

    Science.gov (United States)

    Li, Xueqi; Woodman, Michael; Wang, Selina C

    2015-08-01

    Pheophytins and pyropheophytin are degradation products of chlorophyll pigments, and their ratios can be used as a sensitive indicator of stress during the manufacturing and storage of olive oil. They increase over time depending on the storage condition and if the oil is exposed to heat treatments during the refining process. The traditional analysis method includes solvent- and time-consuming steps of solid-phase extraction followed by analysis by high-performance liquid chromatography with ultraviolet detection. We developed an improved dilute/fluorescence method where multi-step sample preparation was replaced by a simple isopropanol dilution before the high-performance liquid chromatography injection. A quaternary solvent gradient method was used to include a fourth strong solvent wash on a quaternary gradient pump, which avoided the need to premix any solvents and greatly reduced the oil residues on the column from previous analysis. This new method not only reduces analysis cost and time but shows reliability, repeatability, and improved sensitivity, especially important for low-level samples.

  14. Quantitative analysis of lactose and lactulose in urine by high performance liquid chromatography for determination of intestinal lactase activity

    Directory of Open Access Journals (Sweden)

    Nani Dharmasetiawani

    2003-03-01

    Full Text Available Determination of intestinal lactase activity is directly done by measuring its activity in intestinal epithelium. This is an invasive method and ethically can not be done in healthy infants. Indirectly, determination of lactase activity, stated as excretion and ingestion ratio of lactose and lactulose, needs 30 hours hospitalized infants. The aim of this study was to look for a method for determination of lactase activity which is not invasive and not necessary hospitalized. Using this method  lactose and lactulose were given as a single oral load after 2 hours fasting. Urine were collected for 5 hours starting from consuming sugar solution and then lactose and lactulose concentration in the urine were measured by High Performance Liquid Chromatography. The results showed single oral load of lactose and lactulose can be used for determination of lactase activity in infant and the infants were observed only for 7 hours. (Med J Indones 2003; 12: 8-12 Keywords: Lactase activity, Lactulose, Lactose, High Performance Liquid Chromatography

  15. Analysis of microdialysate monoamines, including noradrenaline, dopamine and serotonin, using capillary ultra-high performance liquid chromatography and electrochemical detection.

    Science.gov (United States)

    Ferry, Barbara; Gifu, Elena-Patricia; Sandu, Ioana; Denoroy, Luc; Parrot, Sandrine

    2014-03-01

    Electrochemical methods are very often used to detect catecholamine and indolamine neurotransmitters separated by conventional reverse-phase high performance liquid chromatography (HPLC). The present paper presents the development of a chromatographic method to detect monoamines present in low-volume brain dialysis samples using a capillary column filled with sub-2μm particles. Several parameters (repeatability, linearity, accuracy, limit of detection) for this new ultrahigh performance liquid chromatography (UHPLC) method with electrochemical detection were examined after optimization of the analytical conditions. Noradrenaline, adrenaline, serotonin, dopamine and its metabolite 3-methoxytyramine were separated in 1μL of injected sample volume; they were detected above concentrations of 0.5-1nmol/L, with 2.1-9.5% accuracy and intra-assay repeatability equal to or less than 6%. The final method was applied to very low volume dialysates from rat brain containing monoamine traces. The study demonstrates that capillary UHPLC with electrochemical detection is suitable for monitoring dialysate monoamines collected at high sampling rate.

  16. Analysis of major antioxidants from extracts of Myrmecodia pendans by UV/visible spectrophotometer, liquid chromatography/tandem mass spectrometry, and high-performance liquid chromatography/UV techniques

    Directory of Open Access Journals (Sweden)

    Adam Mekonnen Engida

    2015-06-01

    Full Text Available In the present work, heat reflux extraction with ethanol/water (80:20; v/v as the solvent was used to extract antioxidants from Myrmecodia pendans. The crude extract (CE was fractionated using hexane and ethyl acetate. Ethyl acetate fraction (EAF and aqueous fraction were collected. Antioxidant activity against 1,1-diphenyl-2-picrylhydrazyl-radical radical and ferric reducing power of the CE, EAF, and aqueous fraction were evaluated. EAF showed comparable antioxidant activity against 1,1-diphenyl-2-picrylhydrazyl-radical radical and ferric reducing power to those of the CE. UV/visible, liquid chromatography/electrospray ionization/tandem mass spectrometry, and high-performance liquid chromatography were employed for identifying the major antioxidant compounds in the EAF. Three major phenolic compounds (rosmarinic acid, procyanidin B1, and polymer of procyanidin B1 were identified. The first two compounds were confirmed and quantified by high-performance liquid chromatography using authentic standards, but confirmation of the third compound was hampered by a lack of commercial standard. Concentrations of rosmarinic acid and procyanidin B1 in the EAF were found to be 20.688 ± 1.573 mg/g dry sample and 3.236 ± 0.280 mg/g dry sample, respectively. All these three compounds are reported for the first time in sarang semut.

  17. Sound Velocities of Fe-C and Fe-Si alloying liquids at high pressures

    Science.gov (United States)

    Jing, Z.; Han, J.; Yu, T.; Wang, Y.

    2014-12-01

    Geophysical and geochemical observations suggest light elements such as S, Si, C, O, H, etc., are likely present in the Earth's outer core and the molten cores of other terrestrial planets and moons including Mercury, Mars, Earth's Moon, and Ganymede. In order to constrain the abundances of light elements in planetary cores, it is crucial to determine the density and sound velocity of Fe-light element alloying liquids under core conditions. In this study, sound velocities of Fe-rich liquids were determined by combining the ultrasonic measurements with synchrotron X-ray radiography and diffraction techniques under high-pressure and temperature conditions from 1 to 6 GPa and 1573 to 1973 K. An Fe-C composition (Fe-5wt%C) and four Fe-Si compositions (Fe-10wt%Si, Fe-17wt%Si, Fe-25wt%Si, and FeSi) were studied. Compared to our previous results on the velocity of Fe and Fe-S liquids at high pressures (Jing et al., 2014, Earth Planet. Sci. Lett. 396, 78-87), the presence of both C and Si increases the velocity of liquid Fe, in contrast to the effect of S. The measured velocities of Fe-C and Fe-Si liquids increase with compression and decrease slightly with increasing temperature. Combined with 1-atm density data in the literature, the high-pressure velocity data provide tight constraints on the equations of state and thermodynamic properties such as the adiabatic temperature gradient for Fe-C and Fe-Si liquids. We will discuss these results with implications to planetary cores.

  18. EGFR/cell membrane chromatography-online-high performance liquid chromatography/mass spectrometry method for screening EGFR antagonists from Radix Angelicae Pubescentis

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The intracellular kinase domains of the epidermal growth factor receptor(EGFR) in some tumor cells are significant targets for drug discovery.We have developed a new EGFR cell membrane chromatography(EGFR/CMC)-online-high performance liquid chromatography/mass spectrometry(HPLC/MS) method for screening anti-EGFR antagonists from medicinal herbs such as Radix Angelicae Pubescentis.In this study,the HEK293 EGFR cells with high expression of EGFR were used to prepare cell membrane stationary phase(CMSP) in the EGFR/CMC model.The retention fractions on the EGFR/CMC model were directly analyzed by combining a 10 port columns switcher with a HPLC/MS system online.As a result,osthole from Radix Angelicae Pubescentis was found to be the active component acting on EGFR like dasatinib as the control drug.There was a good relationship between their inhibiting effects on EGFR secretion and HEK293 EGFR cell growth in vitro.This new EGFR/CMC-online-HPLC/MS method can be applied for screening anti-EGFR antagonists from TCMs,for instance,Radix Angelicae Pubescentis.It will be a useful method for drug discovery with natural medicinal herbs as a leading compound resource.

  19. An experimental device for accurate ultrasounds measurements in liquid foods at high pressure

    International Nuclear Information System (INIS)

    The use of high hydrostatic pressure to ensure safe and high-quality product has markedly increased in the food industry during the last decade. Ultrasonic sensors can be employed to control such processes in an equivalent way as they are currently used in processes carried out at room pressure. However, their installation, calibration and use are particularly challenging in the context of a high pressure environment. Besides, data about acoustic properties of food under pressure and even for water are quite scarce in the pressure range of interest for food treatment (namely, above 200 MPa). The objective of this work was to establish a methodology to determine the speed of sound in foods under pressure. An ultrasonic sensor using the multiple reflections method was adapted to a lab-scale HHP equipment to determine the speed of sound in water between 253.15 and 348.15 K, and at pressures up to 700 MPa. The experimental speed-of-sound data were compared to the data calculated from the equation of state of water (IAPWS-95 formulation). From this analysis, the way to calibrate cell path was validated. After this calibration procedure, the speed of sound could be determined in liquid foods by using this sensor with a relative uncertainty between (0.22 and 0.32) % at a confidence level of 95 % over the whole pressure domain.

  20. Speciation analysis of mercury in sediments using ionic-liquid-based vortex-assisted liquid-liquid microextraction combined with high-performance liquid chromatography and cold vapor atomic fluorescence spectrometry.

    Science.gov (United States)

    Leng, Geng; Chen, Wenjin; Wang, Yong

    2015-08-01

    An improved novel method based on ionic liquid vortex-assisted liquid-liquid microextraction has been developed for the extraction of methylmercury, ethylmercury and inorganic mercury in sediment samples prior to analysis by high-performance liquid chromatography with cold vapor atomic fluorescence spectrometry. In this work, mercury species were firstly complexed with dithizone, and the complexes were extracted into 1-hexyl-3-methylimidazolium hexafluorophosphate. Key factors that affect the extraction efficiency of mercury species, such as type and amount of ionic liquid and chelatants, extraction time, sample pH, salt effect and matrix effect were investigated. Under the optimum conditions, linearity was found in the concentration range from 0.1-70 ng/g. Limits of detection ranged from 0.037-0.061 ng/g. Reproducibility and recoveries were assessed by extracting a series of six independent sediment samples that were spiked with different concentration levels. Finally, the proposed method was successfully applied in analysis of real sediment samples. In this work, ionic liquids vortex-assisted liquid-liquid microextraction was for the first time used for the extraction of mercury species in sediment samples. The proposed method was proved to be much simpler and more rapid, as well as more environmentally friendly and efficient compared with the previous methods. PMID:25998155

  1. Traction and nonequilibrium phase behavior of confined sheared liquids at high pressure

    Science.gov (United States)

    Gattinoni, Chiara; Heyes, David M.; Lorenz, Christian D.; Dini, Daniele

    2013-11-01

    Nonequilibrium molecular dynamics simulations of confined model liquids under pressure and sheared by the relative sliding of the boundary walls have been carried out. The relationship between the time-dependent traction coefficient, μ(t), and the state of internal structure of the film is followed from commencement of shear for various control parameters, such as applied load, global shear rate, and solid-liquid atom interaction parameters. Phase diagrams, velocity and temperature profiles, and traction coefficient diagrams are analyzed for pure Lennard-Jones (LJ) liquids and a binary LJ mixture. A single component LJ liquid is found to form semicrystalline arrangements with high-traction coefficients, and stick-slip behavior is observed for high pressures and low-shear velocities, which is shown to involve periodic deformation and stress release of the wall atoms and slip in the solid-liquid boundary region. A binary mixture, which discourages crystallization, gives a more classical tribological response with the larger atoms preferentially adsorbing commensurate with the wall. The results obtained are analyzed in the context of tribology: the binary mixture behaves like a typical lubricant, whereas the monatomic system behaves like a traction fluid. It is discussed how this type of simulation can give insights on the tribological behavior of realistic systems.

  2. Detection of 36 antibiotics in coastal waters using high performance liquid chromatography-tandem mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    NA Guangshui; GU Jia; GE Linke; ZHANG Peng; WANG Zhen; LIU Chunyang; ZHANG Lin

    2011-01-01

    Among pharmaceuticals and personal care products released into the aquatic environment,antibiotics are of particular concern,because of their ubiquity and health effects.Although scientists have recently paid more attention to the threat of antibiotics to coastal ecosystems,researchers have often focused on relatively few antibiotics,because of the absence of suitable analytical methods.We have therefore developed a method for the rapid detection of 36 antibiotic residues in coastal waters,including tetracyclines (TCs),sulfanilamides (SAs),and quinolones (QLs).The method consists of solid-phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis,using electrospray ionization (ESI) in positive mode.The SPE was performed with Oasis HLB and Oasis MCX cartridges.Chromatographic separation on a C18 column was achieved using a binary eluent containing methanol and water with 0.1% formic acid.Typical recoveries of the analytes ranged from 67.4% to 109.3% at a fortification level of 100 ng/L.The precision of the method,calculated as relative standard deviation (RSD),was below 14.6% for all the compounds.The limits of detection (LODs) varied from 0.45 pg to 7.97 pg.The method was applied to determine the target analytes in coastal waters of the Yellow Sea in Liaoning,China.Among the tested antibiotics,31 were found in coastal waters,with their concentrations between the LOD and 212.5 ng/L.These data indicate that this method is valid for analysis of antibiotics in coastal waters.The study first reports such a large number of antibiotics along the Yellow Sea coast of Liaoning,and should facilitate future comprehensive evaluation of antibiotics in coastal ecosystems.

  3. Screening for multiple classes of marine biotoxins by liquid chromatography-high-resolution mass spectrometry.

    Science.gov (United States)

    Blay, Pearl; Hui, Joseph P M; Chang, James; Melanson, Jeremy E

    2011-04-01

    Marine biotoxins pose a significant food safety risk when bioaccumulated in shellfish, and adequate testing for biotoxins in shellfish is required to ensure public safety and long-term viability of commercial shellfish markets. This report describes the use of a benchtop Orbitrap system for liquid chromatography-mass spectrometry (LC-MS) screening of multiple classes of biotoxins commonly found in shellfish. Lipophilic toxins such as dinophysistoxins, pectenotoxins, and azaspiracids were separated by reversed phase LC in less than 7 min prior to MS data acquisition at 2 Hz with alternating positive and negative scans. This approach resulted in mass accuracy for analytes detected in positive mode (gymnodimine, 13-desmethyl spirolide C, pectenotoxin-2, and azaspiracid-1, -2, and -3) of less than 1 ppm, while those analytes detected in negative mode (yessotoxin, okadaic acid, and dinophysistoxin-1 and -2) exhibited mass errors between 2 and 4 ppm. Hydrophilic toxins such as domoic acid, saxitoxin, and gonyautoxins were separated by hydrophilic interaction LC (HILIC) in less than 4 min, and MS data was collected at 1 Hz in positive mode, yielding mass accuracy of less than 1 ppm error at a resolving power of 100,000 for the analytes studied (m/z 300-500). Data were processed by extracting 5 ppm mass windows centered around the calculated masses of the analytes. Limits of detection (LOD) for the lipophilic toxins ranged from 0.041 to 0.10 μg/L (parts per billion) for the positive ions, 1.6-5.1 μg/L for those detected in negative mode, while the domoic acid and paralytic shellfish toxins yielded LODs ranging from 3.4 to 14 μg/L. Toxins were detected in mussel tissue extracts free of interference in all cases.

  4. Determination of anabolic esters in oily formulations and plasma in husbandry using high-performance liquid chromatography and gas chromatography-mass selective detection.

    Science.gov (United States)

    Hooijerink, D; Schilt, R; van Bennekom, E; Brouwer, B

    1994-12-01

    Two different analytical methods are described for the analysis of anabolic steroid esters in oily formulations for veterinary use and animal plasma samples, respectively. For the determination of anabolic steroid esters in oily formulations (at mg kg-1 levels) a reversed-phase high-performance liquid chromatographic method with gradient elution is described. Gradient elution is performed owing to the relatively large variations in polarity of the investigated anabolic steroid esters. For the analysis of anabolic steroid esters in plasma (at ng ml-1 levels) two different strategies are applied. After solid-phase extraction, the plasma samples are introduced into the high-performance liquid chromatography (HPLC) system where the obtained fractions are then analysed by using gas chromatography-mass selective detection (GC-MSD). An alternative method is direct analysis of plasma samples after solid-phase extraction by using GC-MSD without any further clean-up procedure. Prior to GC-MSD the samples are derivatized to corresponding trifluoroacyl (TFA) derivatives. The calibration graph for HPLC is rectilinear over the range 25-150 ng ml-1 plasma and the analytical recoveries for medroxyprogesterone acetate (MPA) and testosterone propionate (TP) are more than 95%. The detection limits for both analytes in GC-MS are 2.5 ng ml-1 plasma for MPA and 0.5 ng ml-1 plasma for TP with an acceptable signal-to-noise ratio (calculated for the derivatized relative molecular mass). In the analysis of plasma obtained from animal experiments concentrations of 6.5 ng ml-1 are found for MPA by using GC-MSD and 5.0 ng ml-1 are found for nortestosterone laurate (NL) by using HPLC. PMID:7879863

  5. Ionic liquid-based ultrasound-assisted emulsification microextraction coupled with high performance liquid chromatography for the determination of four fungicides in environmental water samples.

    Science.gov (United States)

    Liang, Pei; Wang, Fang; Wan, Qin

    2013-02-15

    A highly efficient and environmentally friendly sample preparation method termed ionic liquid-based ultrasound-assisted emulsification microextraction (IL-USAEME) combined with high performance liquid chromatography has been developed for the determination of four fungicides (azoxystrobin, diethofencarb, pyrimethanil and kresoxim-methyl) in water samples. In this novel approach, ionic liquid (IL) was used as extraction solvent in place of the organic solvent used in conventional USAEME assay, and there is no need for using organic dispersive solvent which is typically required in the common dispersive liquid-liquid microextraction method. Various parameters that affect the extraction efficiency, such as the kind and volume of IL, ultrasound emulsification time, extraction temperature and salt addition were investigated and optimized. Under the optimum extraction condition, the linearities of calibration curves were in the range from 3 to 5000 ng mL(-1) for target analytes with the correlation coefficient higher than 0.9992. The enrichment factors and the limits of detection were in the range of 88-137 and 0.73-2.2 ng mL(-1), depending on the analytes. The environmental water samples were successfully analyzed using the proposed method, and the relative recoveries at fortified levels of 50 and 100 ng mL(-1) were in the range of 83.9%-116.2%. PMID:23597988

  6. Highly stable liquid metal-based pressure sensor integrated with a microfluidic channel.

    Science.gov (United States)

    Jung, Taekeon; Yang, Sung

    2015-05-21

    Pressure measurement is considered one of the key parameters in microfluidic systems. It has been widely used in various fields, such as in biology and biomedical fields. The electrical measurement method is the most widely investigated; however, it is unsuitable for microfluidic systems because of a complicated fabrication process and difficult integration. Moreover, it is generally damaged by large deflection. This paper proposes a thin-film-based pressure sensor that is free from these limitations, using a liquid metal called galinstan. The proposed pressure sensor is easily integrated into a microfluidic system using soft lithography because galinstan exists in a liquid phase at room temperature. We investigated the characteristics of the proposed pressure sensor by calibrating for a pressure range from 0 to 230 kPa (R2 > 0.98) using deionized water. Furthermore, the viscosity of various fluid samples was measured for a shear-rate range of 30-1000 s(-1). The results of Newtonian and non-Newtonian fluids were evaluated using a commercial viscometer and normalized difference was found to be less than 5.1% and 7.0%, respectively. The galinstan-based pressure sensor can be used in various microfluidic systems for long-term monitoring with high linearity, repeatability, and long-term stability.

  7. Drug-to-antibody ratio (DAR) and drug load distribution by hydrophobic interaction chromatography and reversed phase high-performance liquid chromatography.

    Science.gov (United States)

    Ouyang, Jun

    2013-01-01

    Hydrophobic interaction chromatography (HIC) is the method of choice for determination of the drug-to-antibody ratio (DAR) and drug load distribution for cysteine (Cys)-linked antibody-drug conjugates (ADCs). The drug-loaded species are resolved based on the increasing hydrophobicity with the least hydrophobic, unconjugated form eluting first and the most hydrophobic, 8-drug form eluting last. The area percentage of a peak represents the relative distribution of the particular drug-loaded ADC species. The weighted average DAR is then calculated using the percentage peak area information and the drug load numbers. Reversed phase high-performance liquid chromatography (RP-HPLC) offers an orthogonal method to obtain DAR for Cys-linked ADCs. The method involves, first, a reduction reaction to completely dissociate the heavy and light chains of the ADC, then separation of the light and heavy chains and their corresponding drug-loaded forms on an RP column. The percentage peak area from integration of the light chain and heavy chain peaks, combined with the assigned drug load for each peak, is used to calculate the weighted average DAR. PMID:23913154

  8. Comparison of high-performance liquid chromatography and supercritical fluid chromatography using evaporative light scattering detection for the determination of plasticizers in medical devices.

    Science.gov (United States)

    Lecoeur, Marie; Decaudin, Bertrand; Guillotin, Yoann; Sautou, Valérie; Vaccher, Claude

    2015-10-23

    Recently, interest in supercritical fluid chromatography (SFC) has increased due to its high throughput and the development of new system improving chromatographic performances. However, most papers dealt with fundamental studies and chiral applications and only few works described validation process of SFC method. Likewise, evaporative light scattering detection (ELSD) has been widely employed in liquid chromatography but only a few recent works presented its quantitative performances hyphenated with SFC apparatus. The present paper discusses about the quantitative performances of SFC-ELSD compared to HPLC-ELSD, for the determination of plasticizers (ATBC, DEHA, DEHT and TOTM) in PVC tubing used as medical devices. After the development of HPLC-ELSD, both methods were evaluated based on the total error approach using accuracy profile. The results show that HPLC-ELSD was more precise than SFC-ELSD but lower limits of quantitation were obtained by SFC. Hence, HPLC was validated in the ± 10% acceptance limits whereas SFC lacks of accuracy to quantify plasticizers. Finally, both methods were used to determine the composition of plasticized-PVC medical devices. Results demonstrated that SFC and HPLC both hyphenated with ELSD provided similar results.

  9. Chiral separation of neonicotinoid insecticides by polysaccharide-type stationary phases using high-performance liquid chromatography and supercritical fluid chromatography.

    Science.gov (United States)

    Zhang, Cheng; Jin, Lixia; Zhou, Shanshan; Zhang, Yifan; Feng, Shuoli; Zhou, Qinyan

    2011-03-01

    The enantiomeric separations of three neonicotinoid insecticides (identified as compounds 1, 2, and 3) were performed on three polysaccharide-type chiral columns, that is, Chiralcel OD-H, Chiralpak AD-H, and Chiralpak IB, by high-performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC). Effects of the modifier percentage and column temperature on chiral recognitions of chiral stationary phases were also studied. Both 1 and 2 could be resolved on all three columns selected, with the highest R(s) values obtained on Chiralpak AD-H and Chiralcel OD-H, respectively. However, satisfactory separation of the four stereoisomers of 3 was only achieved on Chiralcel OD-H. Considering the effects of ethanol on the values of k, α, and R(s), we concluded that hydrogen bonding, π-π, and/or dipole-dipole interactions might be all responsible for the chiral separation. In comparison to HPLC, a shorter run time was achieved for 1 and 2 by SFC. However, 3 could not be stereoselectively resolved using SFC. On the basis of the calculated thermodynamic parameters, we found that the separation processes of enantiomers of 1 and 2 were entropy controlled and enthalpy controlled, respectively.

  10. Stability of Y-90 Zevalin: Radiochemical purity evaluation using instant thin layer and size exclusion high performance liquid chromatography

    International Nuclear Information System (INIS)

    Aim: The purpose of the study was to evaluate the stability of typical Y-90 Zevalin (IDEC Pharmaceuticals Corp) patient doses, either maintained at room temperature or refrigerated, using the manufacturer's recommended instant thin layer chromatography procedure and confirming the results using size exclusion high performance liquid chromatography (HPLC) to evaluate radiochemical purity. Material and Methods: Following radiolabeling of Y-90 Zevalin, two patient doses were withdrawn into a 10-ml syringe. One patient dose, consisting of 41.2 mCi Y-90 Zevalin in 10 ml, was refrigerated. The other patient dose, consisting of 31.2 mCi Y-90 Zevalin in 7.3 ml, was maintained at room temperature. At selected time intervals after formulation, ranging from 0.5 to 49 hrs, radiochemical purity evaluations were performed using instant thin layer chromatography (ITLC-SG) with normal saline and size exclusion HPLC using a TSKgel G3000SW molecular sizing column. For each time interval, five separate samples were analyzed and the data statistically summarized. Results: Following initial radiolabeling, the radiochemical purity of all preparations evaluated was greater than 95%, as demonstrated by both chromatographic methods. At 24 hours post radiolabeling, the mean radiochemical purity of Y-90 Zevalin, refrigerated or maintained at room temperature, was 95.4% ± 0.3% (s.d.) and 86.3% ± 1.2% (s.d), respectively using instant thin layer chromatography. At 48 hours post radiolabeling, the mean radiochemical purity of Y-90 Zevalin, refrigerated or maintained at room temperature, was 91.0% ±± 0.8% (s.d.) and 86.0% ± 2.0% (s.d.), respectively using instant thin layer chromatography. In general, size exclusion HPLC confirmed the chromatographic results. With increased time post radiolabeling, an increase in radiolabeled low molecular weight components (Y-90 DTPA) and an increase in radiolabeled high molecular weight components and/or aggregates was observed. These radiochemical

  11. Quantitative determination of dexamethasone in bovine milk by liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry.

    Science.gov (United States)

    Cherlet, Marc; De Baere, Siegrid; De Backer, Patrick

    2004-06-01

    Dexamethasone (DXM) is a synthetic glucocorticoid that is authorized for therapeutic use in veterinary medicine. The European Community (EC) fixed a maximum residue limit (MRL) at 2ng/g for liver, 0.75ng/g for muscle and kidney tissues, and 0.3ng/ml for milk, while its use as growth-promoter is completely banned. The purpose of this study was to develop and validate a simple and reliable method to determine DXM residues in bovine milk. Milk proteins were removed by the addition of concentrated trichloroacetic acid and paper filtration. Solid-phase extraction clean-up on a C18 reversed phase column was performed to obtain an extract suitable for liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Chromatographic separation of DXM and the internal standard desoximetasone, was achieved on a PLRP-S polymeric reversed phase column, using a mixture of 0.1% (v/v) acetic acid in water (mobile phase A) and acetonitrile (mobile phase B) as the mobile phases. They were identified using the MS/MS detection technique, and were subsequently quantified. The method has been validated according to the requirements of the EC at 0.15, 0.30 and 0.60ng/ml (being half the MRL, the MRL and double the MRL levels fixed by the EC). Calibration graphs were prepared in the 0.15-5ng/ml range and good linearity was achieved (r>or=0.99 and goodness of fit

  12. Rapid determination of Papaver somniferum alkaloids in process streams using monolithic column high-performance liquid chromatography with chemiluminescence detection

    International Nuclear Information System (INIS)

    We have combined high-performance liquid chromatography (HPLC) separations using a monolithic column with acidic potassium permanganate and tris(2,2'-bipyridyl)ruthenium(II) chemiluminescence detection in a rapid and highly sensitive method to monitor the process of extracting opiate alkaloids from Papaver somniferum. Due to the high flow rates allowed with the monolithic column and the inherent selectivity of the chemiluminescence reactions, the four predominant alkaloids - morphine, codeine, oripavine and thebaine - were determined in less than 2 min. The results obtained with numerous process samples compared favourable with those of the standard HPLC methodology. Limits of detection were 1 x 10-10 M, 5 x 10-10 M, 5 x 10-10 M and 1 x 10-9 M, for morphine, codeine, oripavine and thebaine, respectively

  13. Qualitative and quantitative two-dimensional thin-layer chromatography/high performance liquid chromatography/diode-array/electrospray-ionization-time-of-flight mass spectrometry of cholinesterase inhibitors.

    Science.gov (United States)

    Mroczek, Tomasz

    2016-09-10

    Recently launched thin-layer chromatography-mass spectrometry (TLC-MS) interface enabling extraction of compounds directly from TLC plates into MS ion source was unusually extended into two-dimensional thin-layer chromatography/high performance liquid chromatography (2D, TLC/HPLC) system by its a direct connection to a rapid resolution 50×2.1mm, I.D. C18 column compartment followed by detection by diode array (DAD) and electrospray ionisation time-of-flight mass spectrometry (ESI-TOF-MS). In this way, even not separated bands of complicated mixtures of natural compounds could be analysed structurally, only within 1-2min after development of TLC plates. In comparison to typically applied TLC-MS interface, no ion suppression for acidic mobile phases was observed. Also, substantial increase in ESI-TOF-MS sensitivities and quality of spectra, were noticed. It has been utilised in combination with TLC- based bioautographic approaches of acetylcholinesterase (AChE) inhibitors, However, it can be also applied in any other procedures related to bioactivity (e.g. 2,2-Diphenyl-1-picryl-hydrazyl-DPPH screen test for radicals). This system has been also used for determination of half maximal inhibitory concentration (IC50 values) of the active inhibitor-galanthamine, as an example. Moreover, AChE inhibitory potencies of some of purified plant extracts, never studied before, have been quantitatively measured. This is first report of usage such the 2D TLC/HPLC/MS system both for qualitative and quantitative evaluation of cholinesterase inhibitors in biological matrices.

  14. Evaluation of Carbohydrates in Natural and Cultured Cordyceps by Pressurized Liquid Extraction and Gas Chromatography Coupled with Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Jia Guan

    2010-06-01

    Full Text Available Free and polymeric carbohydrates in Cordyceps, a valued edible mushroom and well-known traditional Chinese medicine, were determined using stepwise pressurized liquid extraction (PLE extraction and GC-MS. Based on the optimized PLE conditions, acid hydrolysis and derivatization, ten monosaccharides, namely rhamnose, ribose, arabinose, xylose, mannose, glucose, galactose, mannitol, fructose and sorbose in 13 samples of natural and cultured Cordyceps were qualitatively and quantitatively analyzed and compared with myo-inositol hexaacetate as internal standard. The results showed that natural C. sinensis contained more than 7.99% free mannitol and a small amount of glucose, while its polysaccharides were usually composed of mannose, glucose and galactose with a molar ratio of 1.00:16.61~3.82:1.60~1.28. However, mannitol in cultured C. sinensis and cultured C. militaris were less than 5.83%, and free glucose was only detected in a few samples, while their polysaccharides were mainly composed of mannose, glucose and galactose with molar ratios of 1.00:3.01~1.09:3.30~1.05 and 1.00:2.86~1.28:1.07~0.78, respectively. Natural and cultured Cordyceps could be discriminated by hierarchical clustering analysis based on its free carbohydrate contents.

  15. Trace determination of 13 haloacetamides in drinking water using liquid chromatography triple quadrupole mass spectrometry with atmospheric pressure chemical ionization.

    Science.gov (United States)

    Chu, Wenhai; Gao, Naiyun; Yin, Daqiang; Krasner, Stuart W; Templeton, Michael R

    2012-04-27

    The haloacetamides (HAcAms) are disinfection by-products (DBPs) in drinking water which are currently receiving increased scientific attention due to their elevated toxicity relative to regulated disinfection by-products. A simultaneous determination method of 13 HAcAms, combining solid-phase extraction (SPE) enrichment, liquid chromatographic (LC) separation, and triple quadrupole mass spectrometry (tqMS) detection with atmospheric pressure chemical ionization (APCI) using selective reaction monitoring in positive mode, was developed to measure HAcAms, including chlorinated, brominated, and iodinated analogs. Ammonium chloride and Oasis HLB were selected as the dechlorinating reagent and polymeric SPE sorbent of HAcAm samples. The used tqMS apparatus showed higher sensitivity for the studied HAcAms in the APCI mode than electrospray ionization. 13 HAcAms were separated by LC in 9.0 min, and the detection limits ranged from 7.6 to 19.7 ng/L. The SPE-LC/tqMS method was successfully applied to quantify 13 HAcAms in drinking water samples for the first time, and first indentified tribromoacetamide and chloroiodoacetamide as DBPs in drinking water.

  16. Development of poison injection code-COPJET for high pressure liquid poison injection in pressure tube type heavy water reactor

    International Nuclear Information System (INIS)

    Shut Down System-2 (SDS-2) in advanced vertical pressure tube type reactor, provides rapid reactor shutdown by high pressure injection of a neutron absorbing liquid called poison, into the moderator in the calandria. Poison inside the calandria is distributed by poison jets issued from holes provided in the injection tubes. Effectiveness of the system depends on the rate and spread of the poison in the moderator. In this study, a transient one-dimensional (1-D) hydraulic code, COPJET is developed, to predict the performance of system by predicting poison jet length with time. Validation of the COPJET is done with the data available in literature. Thereafter, it is applied for poison jet length prediction of advanced vertical pressure type reactor. (author)

  17. Equations of states for an ionic liquid under high pressure: A molecular dynamics simulation study

    International Nuclear Information System (INIS)

    Highlights: • We compare different equation of states, EoS, for an ionic liquid under high pressure. • Molecular dynamics, MD, simulations have been used to evaluate the best EoS. • MD simulations show that a group contribution model can be extrapolated to P ∼ 1.0 GPa. • A perturbed hard-sphere EoS also fits the densities calculated by MD simulations. - Abstract: The high-pressure dependence of density given by empirical equation of states (EoS) for the ionic liquid 1-butyl-3-methylimidazolium trifluoromethanesulfonate (or triflate), [C4C1im][TfO], is compared with results obtained by molecular dynamics (MD) simulations. Two EoS proposed for [C4C1im][TfO] in the pressure range of tens of MPa, which give very different densities when extrapolated to pressures beyond the original experiments, are compared with a group contribution model (GCM). The MD simulations provide support that one of the empirical EoS and the GCM is valid in the pressure range of hundreds of MPa. As an alternative to these EoS that are based on modified Tait equations, it is shown that a perturbed hard-sphere EoS based on the Carnahan–Starling–van der Waals equation also fits the densities calculated by MD simulations of [C4C1im][TfO] up to ∼1.0 GPa

  18. Simultaneous determination of pseudoephedrine hydrochloride and cetrizine hydrochloride by reverse phase high performance liquid chromatography

    OpenAIRE

    Nalini C; Kavitha K

    2006-01-01

    A reversed phase high performance liquid chromatographic method has been developed using Shimadzu HPLC-VP series, LC-10 ATV pump, SPD10 AVP and C8 column, for simultaneous determination of pseudoephedrine hydrochloride and cetrizine hydrochloride in three marketed tablet formulations (extended release). The mobile phase consists of phosphate buffer of pH 7.0 and acetonitrile HPLC grade in the ratio of 1:1. The flow rate was maintained at 1 ml/min and the ultraviolet detection was done at 242 ...

  19. Determination of Constituents in Hair Dyes by Reversed-phase High-Performance Liquid Chromatography

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A reversed-phase high-performance liquid chromatographic method for the separation and quantitation of 1,4-phenylenediamine, 4-aminophenol, 3-aminophenol, 1,3-benzendiol and 2,6-phenylenediamine in hair dyes was developed. The separation was carried out on a μ-Bondapak C18 column with methanol-water containing 0.1% triethylamine and 0.02 mol/L NH4Ac (pH=5.20) (10:90, vol./vol.) as the mobile phase. Two real samples were analyzed.

  20. Fatty acids by high-performance liquid chromatography and evaporative light-scattering detector.

    Science.gov (United States)

    Bravi, Elisabetta; Perretti, Giuseppe; Montanari, Luigi

    2006-11-17

    A high-performance liquid chromatographic (HPLC) separation method with an evaporative light-scattering detector (ELSD) has been developed for the separation and quantitative analysis of fatty acid methyl esters (FAME) in three different oils. Reverse-phased C18 HPLC separation of 13 FAME is achieved using a methanol/water eluent mixture. The retention times (RT) reflect the elution behavior of these compounds on C18 reversed-phase HPLC. The proposed method is tested on: soybean oil (Glycine max L.) as reference sample, rice bran oil (Oryza sativa L.), pumpkin seed oil (Cucurbita pepo L.) and algal oil (Arthrospira platensis Nordst.). PMID:17007865

  1. Simultaneous determination of pseudoephedrine hydrochloride and cetrizine hydrochloride by reverse phase high performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Nalini C

    2006-01-01

    Full Text Available A reversed phase high performance liquid chromatographic method has been developed using Shimadzu HPLC-VP series, LC-10 ATV pump, SPD10 AVP and C8 column, for simultaneous determination of pseudoephedrine hydrochloride and cetrizine hydrochloride in three marketed tablet formulations (extended release. The mobile phase consists of phosphate buffer of pH 7.0 and acetonitrile HPLC grade in the ratio of 1:1. The flow rate was maintained at 1 ml/min and the ultraviolet detection was done at 242 nm, which is the isosbestic point. Linearity coefficients, assay values, recovery studies and repeatability studies showed that the method is accurate and precise.

  2. Triggering the Chemical Instability of an Ionic Liquid under High Pressure.

    Science.gov (United States)

    Faria, Luiz F O; Nobrega, Marcelo M; Temperini, Marcia L A; Bini, Roberto; Ribeiro, Mauro C C

    2016-09-01

    Ionic liquids are an interesting class of materials due to their distinguished properties, allowing their use in an impressive range of applications, from catalysis to hypergolic fuels. However, the reactivity triggered by the application of high pressure can give rise to a new class of materials, which is not achieved under normal conditions. Here, we report on the high-pressure chemical instability of the ionic liquid 1-allyl-3-methylimidazolium dicyanamide, [allylC1im][N(CN)2], probed by both Raman and IR techniques and supported by quantum chemical calculations. Our results show a reaction occurring above 8 GPa, involving the terminal double bond of the allyl group, giving rise to an oligomeric product. The results presented herein contribute to our understanding of the stability of ionic liquids, which is of paramount interest for engineering applications. Moreover, gaining insight into this peculiar kind of reactivity could lead to the development of new or alternative synthetic routes to achieve, for example, poly(ionic liquids). PMID:27470147

  3. An optimized gossypol high-performance liquid chromatography assay and its application in evaluation of different gland genotypes of cotton

    Indian Academy of Sciences (India)

    Yingfan Cai; Hong Zhang; Yu Zeng; Jianchuan Mo; Jinku Bao; Chen Miao; Jie Bai; Fang Yan; Fang Chen

    2004-03-01

    A comparative study on gossypol content of various genetic types of pigment glands of cotton varieties was conducted through an optimized high-performance liquid chromatography (HPLC) on a C18 column (4.6 mm × 250 mm, 5 m particle) with methanol–0.5% acetic acid aqueous solution, 90 : 10 (v/v), as mobile phase, at a flow rate of 0.8 ml/min and UV detection at 254 nm. The method was shown to be highly reproducible, with precision [as relative standard deviation (RSD)] and accuracy [as relative mean error (RME)] < 10%, both intra-day and inter-day. Absolute recoveries were > 94%. The results revealed major differences among the different gland varieties or species of cotton, including the special and ordinary glandless and glanded Gossypium hirsutum, G. barbadense, and displayed the precious resources of different glands of extraordinary cotton.

  4. Modernization of Chinese herbal compound and the high performance liquid chromatography tandem mass spectrometry (HPLC-MS)

    Institute of Scientific and Technical Information of China (English)

    LI Wen-lan; SUN Zhi; DU Juan

    2008-01-01

    Chinese herbal compound is playing an important role on curing human diseases. And it has been a trend that Chinese herbal compound is being used all over the world in 21 century. However, our Chinese herbal compound is facing serious challenge for the lack of canonical system of quality criterion for Chinese herbal compound so it has been a urgent problem to set up the quality control standards and reveal therapeutic basis of Chinese herbal compound. In order to give full play to the advantages of Chinese herbal compound, modern scientific and technological is used to research of Chinese herbal compound, especially the high performance liquid chromatography tandem mass spectrometry(HPLC-MS), because it is high sensitive, rapid, and obtain more information. It is very necessary that HPLC-MS is uesed to elucidate the effective components of basic substances of Chinese Herbal Compound, and endow traditional Chinese medicine with modern scientific connotation.

  5. Identification of tyrosinase specific inhibitors from Xanthium strumarium fruit extract using ultrafiltration-high performance liquid chromatography.

    Science.gov (United States)

    Wang, Zhiqiang; Hwang, Seung Hwan; Huang, Bo; Lim, Soon Sung

    2015-10-01

    In this study, a strategy based on ultrafiltration-high performance liquid chromatography coupled with diode array detection (UF-HPLC-DAD) was proposed for screening tyrosinase specific inhibitors in Xanthii fructus. The false negatives were distinguished by optimizing the UF-HPLC-DAD parameters to reduce the background noise; the false positives were distinguished by introducing a blocked tyrosinase in the control group for comparison. To obtain the best blocker, the competitive experiments were performed using various known ligands. Using this strategy, three competitive inhibitors (protocatechuic acid; 3,5-di-O-caffeoylquinic acid; and 1,5-di-O-caffeoylquinic acid) and one mixed-type inhibitor (chlorogenic acid) were identified. These results were verified using tyrosinase inhibition assay, kinetic analysis, and structural simulation of the complex. Our experimental results suggest that the proposed strategy could be useful for high-throughput identification of tyrosinase specific inhibitors in natural products. PMID:26367464

  6. High temperatures and high pressures Brillouin scattering studies of liquid H(2)O+CO(2) mixtures.

    Science.gov (United States)

    Qin, Junfeng; Li, Min; Li, Jun; Chen, Rongyan; Duan, Zhenhao; Zhou, Qiang; Li, Fangfei; Cui, Qiliang

    2010-10-21

    The Brillouin scattering spectroscopy studies have been conducted in a diamond anvil cell for a liquid mixtures composed of 95 mol % H(2)O and 5 mol % CO(2) under high temperatures and pressures. The sound velocity, refractive index, density, and adiabatic bulk modulus of the H(2)O+CO(2) mixtures were determined under pressures up to the freezing point at 293, 453, and 575 K. It is found from the experiment that sound velocities of the liquid mixture are substantially lower than those of pure water at 575 K, but not at lower temperatures. We presented an empirical relation of the density in terms of pressure and temperature. Our results show that liquid H(2)O+CO(2) mixtures are more compressible than water obtained from an existing equation of state of at 453 and 575 K. PMID:20969409

  7. Method development for the determination of selected pesticides on tobacco by high-performance liquid chromatography-electrospray ionisation-tandem mass spectrometry.

    Science.gov (United States)

    Mayer-Helm, Bernhard; Hofbauer, Ludwig; Müller, Jutta

    2008-02-15

    A method was developed for the quantitative determination of alachlor, benalaxyl, clomazone, diflubenzuron, dimethomorph, diphenamid, ethofumesate, metalaxyl, methoprene, metobromuron and piperonyl butoxide on tobacco. The pesticides were extracted with water and methanol from five different types of tobacco. The extracts were purified by partition on an extraction cartridge containing diatomaceous earth. The purified extracts were analysed by reversed-phase high-performance liquid chromatography connected to an atmospheric pressure ionisation-electrospray-triple quadrupole mass spectrometer operating in the positive ion mode. Two different transitions and their relative intensities were monitored for unambiguous identification. All pesticides presented overall recovery rates between 35% and 110%. The trueness is near 100% and the interday precision is below 15%. The limits of quantifications are equal or below the guidance residue levels proposed by the Agrochemical Advisory Committee of CORESTA, an association of organisations having scientific research relative to tobacco.

  8. Online profiling of triacylglycerols in plant oils by two-dimensional liquid chromatography using a single column coupled with atmospheric pressure chemical ionization mass spectrometry.

    Science.gov (United States)

    Wei, Fang; Ji, Shu-Xian; Hu, Na; Lv, Xin; Dong, Xu-Yan; Feng, Yu-Qi; Chen, Hong

    2013-10-18

    The complexity of natural triacylglycerols (TAGs) in various edible oils is high because of the hundreds of TAG compositions, which makes the profiling of TAGs quite difficult. In this investigation, a rapid and high-throughput method for online profiling of TAGs in plant oils by two-dimensional (2D) liquid chromatography using a single column coupled with atmospheric pressure chemical ionization (APCI) mass spectrometry was reported. A novel mixed-mode 2D chromatographic column packed with silver-ion-modified octyl and sulfonic co-bonded silica was employed in this online 2D separation system. This novel 2D column combined the features of C8 column and silver-ion. In comparison with the traditional C18 column and silver-ion column, which are the two main columns used for the separation of complex TAGs in natural oil samples, this novel 2D column, could provide hydrophobic interactions as well as π-complexation interactions. It exhibited much higher selectivity for the separation of TAGs, and the separation was rapid. This online 2D separation system was successful in the separation of a large number of TAG solutes, and the TAG structures were evaluated by analyzing their APCI mass spectra information. This system was applied for the profiling of TAGs in peanut oils, corn oils, and soybean oils. 30 TAGs in peanut oils, 18 TAGs in corn oils, and 21 TAGs in soybean oils were determined and quantified. The highest relative content of TAGs was LLL, which was found in corn oil with the relative content up to 45.43 (%, w/w), and the lowest relative content of TAGs was LLS and OSS, which was found in soybean oil and corn oil respectively, with the relative content only 0.01 (%, w/w). In addition, the TAG data were analyzed by principal component analysis (PCA). Results of PCA enabled a clear identification of different plant oils. This method provided an efficient and convenient chromatographic technology for the fast characterization and quantification of complex TAGs

  9. Construction of an Ultrahigh Pressure Liquid Chromatography-Tandem Mass Spectral Library of Plant Natural Products and Comparative Spectral Analyses.

    Science.gov (United States)

    Lei, Zhentian; Jing, Li; Qiu, Feng; Zhang, Hua; Huhman, David; Zhou, Zhiqin; Sumner, Lloyd W

    2015-07-21

    A plant natural product tandem mass spectral library has been constructed using authentic standards and purified compounds. Currently, the library contains 1734 tandem mass spectra for 289 compounds, with the majority (76%) of the compounds being plant phenolics such as flavonoids, isoflavonoids, and phenylpropanoids. Tandem mass spectra and chromatographic retention data were acquired on a triple quadrupole mass spectrometer coupled to an ultrahigh pressure liquid chromatograph using six different collision energies (CEs) (10-60 eV). Comparative analyses of the tandem mass spectral data revealed that the loss of ring substituents preceded the C-ring opening during the fragmentation of flavonoids and isoflavonoids. At lower CE (i.e., 10 and 20 eV), the flavonoids and isoflavonoid central ring structures typically remained intact, and fragmentation was characterized by the loss of the substituents (i.e., methyl and glycosyl groups). At higher CE, the flavonoid and isoflavonoid core ring systems underwent C-ring cleavage and/or rearrangement depending on the structure, particularly hydroxylation patterns. In-source electrochemical oxidation was observed for phenolics that had ortho-diphenol moieties (i.e., vicinal hydroxyl groups on the aromatic rings). The ortho-diphenols were oxidized to ortho-quinones, yielding an intensive and, in most cases, a base ion peak corresponding to a [(M - 2H) - H](-) ion in their mass spectra. The library also contains reverse-phase retention times, allowing for the construction, validation, and testing of an artificial neural network retention prediction of other flavonoids and isoflavonoids not contained within the library. The library is freely available for nonprofit, academic use and it can be downloaded at http://www.noble.org/apps/Scientific/WebDownloadManager/DownloadArea.aspx.

  10. Multimode gradient high performance liquid chromatography mass spectrometry method applicable to metabolomics and environmental monitoring.

    Science.gov (United States)

    Ammann, Adrian A; Suter, Marc J-F

    2016-07-22

    Metabolomics or environmental investigations generate samples containing very large numbers of small molecular weight analytes. A single mode chromatographic separation excludes a substantial part of such complex analyte mixtures. For instance, a reversed-phase separation would not retain ionic species, resulting in a correspondingly huge front peak. To address this problem, we used two commercially available mixed-mode ion-exchange reversed-phase columns (WAX-1 and WCX-1) in sequence in a novel multimode separation method. After trapping hydrophobics on a C18-trap in loop position, hydrophilics passing the trap are separated by a simultaneous gradient for HILIC, anion and cation exchange chromatography. This gradient ends in a washout phase with a high percentage of water, the correct starting conditions for a reversed-phase gradient eluting hydrophobics from the trap in a second step of the run. Amino acids (9), organic acids (2), sugars (8), fatty acid derived compounds (11), antioxidants (4), miscellanea (6) and xenobiotics (4) were analyzed. Compounds were separated after a single sample injection during a 50min run. Lipids derived small fatty acids up to a chain length of 12 carbons were also accessible within this run time. PMID:27324626

  11. Early detection of degraded A14-125I-insulin in human fibroblasts by the use of high performance liquid chromatography

    International Nuclear Information System (INIS)

    We studied the metabolism of A14-125I-insulin in intact human fibroblasts using high performance liquid chromatography (HPLC) to detect and separate its early degradation products. The high resolving power of HPLC enabled us to separate what has been considered ''intact insulin'' by Sephadex G-50 chromatography or TCA precipitability into two additional peaks that had decreased biochemical properties with respect to immunoprecipitability and receptor binding but not decreased TCA precipitability. We conclude that human fibroblast is capable of metabolizing insulin within 2 min at 37 degrees C into intermediate molecules that can be detected by HPLC but not by TCA precipitability or molecular sieve chromatography

  12. Fundamental and practical studies on high-performance liquid affinity chromatography of biopolymers with novel stationary phases

    Energy Technology Data Exchange (ETDEWEB)

    Bacolod, M.D.

    1992-01-01

    Rigid microparticulate stationary phases having surface-bound metal chelating functions were developed and evaluated in high performance metal chelate affinity chromatography of proteins. Silica- and polystyrene-divinylbenzene-based metal chelate sorbents were produced in wide pore and in non-porous type of column packings. A major effort has been placed on development of non-porous highly crosslinked polystyrene-divinylbenzene (PSDVB). These PSDVB microparticles were produced by a two-step swelling polymerization, and exhibited excellent mechanical strength over a wide range of flow-rates and composition used in high performance liquid chromatography (HPLC). Simple and reproducible hydrophilic coatings were developed for the surface modification of hydrophobic PSDVB supports. A tetradentate metal chelating ligand, ethylenediamine-N, N[prime]-diacetic acid (EDDA), was covalently bound to the surface of the various supports. Sorbents having iminodiacetic acid (IDA) metal chelating functions were also evaluated. The hydrophilic character and surface coverage of various stationary phases were assessed chromatographically. Studies concerning the effects of eluent pH as well as the nature and concentration of salts on retention and selectivity with different metal chelate stationary phases having various immobilized metal ions were carried out. Elution schemes were developed for rapid separation of proteins in metal chelate affinity chromatography. EDDA stationary phases in metal forms can be viewed as complementary to IDA stationary phases since they afforded different selectivity and retentivity toward proteins. Hydrophilic PSDVB could be functionalized with IDA or EDDA metal chelating ligands or lectins. The non-porous metal chelate stationary phases afforded rapid separation of proteins by the development of multiple gradient systems, which permitted higher column peak capacity, enabling the separation of a greater number of proteins in a single chromatographic run.

  13. Experimental study on liquid immiscibility of lamprophyre-sulfide melt at high temperature and high pressure and its geological significance

    Institute of Scientific and Technical Information of China (English)

    LI Bo; HUANG Zhilong; ZHU Chengming

    2009-01-01

    With lamprophyre and pyrite from the Laowangzhai gold deposit, Yunnan Province, China, as starting materials, and at pressures from 1.5 to 3.0 GPa and temperatures from 1160 to 1560℃, an experimental study was carried out on the liquid immiscibility of lamprophyre-sulfide melt at high temperature and ultra-high pressure in the DS-29A cubic 3600T/6-type high pressure apparatus. Results showed that the liquid immiscibility of lampropyre-sulfide melt in the magmatic system would happen during the early magmatic evolution (high temperature and high pressure conditions) and was controlled by temperature and pressure. The sulfide melt which was separated from the lamprophyric melt would make directional movement in the temperature and pressure field and assemble in the low-temperature and low-pressure region. Because the density of SM is higher than that of the lamprophyric melt, the former would gather together at the bottom of the magma chamber and there would exist a striking boundary between the two melts. On the other hand, the results also suggested that there would be little possibility for lamprophyric magma to carry massive gold, and lamprophyres can't provide many of ore-forming materials (Au) in the processes of gold mineralization.

  14. [Qualitative and quantitative analysis of amygdalin and its metabolite prunasin in plasma by ultra-high performance liquid chromatography-tandem quadrupole time of flight mass spectrometry and ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry].

    Science.gov (United States)

    Gao, Meng; Wang, Yuesheng; Wei, Huizhen; Ouyang, Hui; He, Mingzhen; Zeng, Lianqing; Shen, Fengyun; Guo, Qiang; Rao, Yi

    2014-06-01

    A method was developed for the determination of amygdalin and its metabolite prunasin in rat plasma after intragastric administration of Maxing shigan decoction. The analytes were identified by ultra-high performance liquid chromatography-tandem quadrupole time of flight mass spectrometry and quantitatively determined by ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry. After purified by liquid-liquid extraction, the qualitative analysis of amygdalin and prunasin in the plasma sample was performed on a Shim-pack XR-ODS III HPLC column (75 mm x 2.0 mm, 1.6 microm), using acetonitrile-0.1% (v/v) formic acid aqueous solution. The detection was performed on a Triple TOF 5600 quadrupole time of flight mass spectrometer. The quantitative analysis of amygdalin and prunasin in the plasma sample was performed by separation on an Agilent C18 HPLC column (50 mm x 2.1 mm, 1.7 microm), using acetonitrile-0.1% (v/v) formic acid aqueous solution. The detection was performed on an AB Q-TRAP 4500 triple quadrupole mass spectrometer utilizing electrospray ionization (ESI) interface operated in negative ion mode and multiple-reaction monitoring (MRM) mode. The qualitative analysis results showed that amygdalin and its metabolite prunasin were detected in the plasma sample. The quantitative analysis results showed that the linear range of amygdalin was 1.05-4 200 ng/mL with the correlation coefficient of 0.999 0 and the linear range of prunasin was 1.25-2 490 ng/mL with the correlation coefficient of 0.997 0. The method had a good precision with the relative standard deviations (RSDs) lower than 9.20% and the overall recoveries varied from 82.33% to 95.25%. The limits of detection (LODs) of amygdalin and prunasin were 0.50 ng/mL. With good reproducibility, the method is simple, fast and effective for the qualitative and quantitative analysis of the amygdalin and prunasin in plasma sample of rats which were administered by Maxing shigan decoction.

  15. Using glucaminium-based ionic liquids for improving the separation of 2-aminopyrimidine-5-ylboronic acid and its pinacol ester by high performance liquid chromatography.

    Science.gov (United States)

    Joshi, Manishkumar D; Li, Tianhao; Zhong, Qiqing; Anderson, Jared L

    2013-09-20

    A reversed-phase high performance liquid chromatography (HPLC) method is described for the determination of boronic acids that are commonly present as impurities in pinacolboronate ester reagents. Boronic acids and their pinacolboronate esters are key reagents in the Suzuki-Miyaura coupling reaction. The retention of hydrophilic boronic acids in reversed-phase chromatography is often a challenge, especially in very high pH mobile phases, which are needed to mitigate the on-column degradation of pinacolboronate esters. In this study, a hydrophilic boronic acid, 2-aminopyrimidine-5-ylboronic acid, was complexed with specifically functionalized glucaminium-based ionic liquids that were added to the diluent. The two glucaminium-based ILs possess cis-diol moieties that are capable of forming complexes with boronic acids. In addition, aromatic functional groups within the glucaminium cation allow strong π-π interactions with the polymeric stationary phase. Using this approach, the limit of detection for 2-aminopyrimidine-5-ylboronic acid was found to be 3-4μM. The quantification of 2-aminopyrimidine-5-ylboronic acid within a 2-aminopyrimidine-5-pinacolboronate ester sample was successfully achieved using this method. PMID:23958694

  16. High pressure combustion of liquid fuels. [alcohol and n-paraffin fuels

    Science.gov (United States)

    Canada, G. S.

    1974-01-01

    Measurements were made of the burning rates and liquid surface temperatures for a number of alcohol and n-paraffin fuels under natural and forced convection conditions. Porous spheres ranging in size from 0.64-1.9 cm O.D. were emloyed to simulate the fuel droplets. The natural convection cold gas tests considered the combustion in air of methanol, ethanol, propanol-1, n-pentane, n-heptane, and n-decane droplets at pressures up to 78 atmospheres. The pressure levels of the natural convection tests were high enough so that near critical combustion was observed for methanol and ethanol vaporization rates and liquid surface temperature measurements were made of droplets burning in a simulated combustion chamber environment. Ambient oxygen molar concentrations included 13%, 9.5% and pure evaporation. Fuels used in the forced convection atmospheric tests included those listed above for the natural convection tests. The ambient gas temperature ranged from 600 to 1500 K and the Reynolds number varied from 30 to 300. The high pressure forced convection tests employed ethanol and n-heptane as fuels over a pressure range of one to 40 atmospheres. The ambient gas temperature was 1145 K for the two combustion cases and 1255 K for the evaporation case.

  17. Determination of nine high-intensity sweeteners in various foods by high-performance liquid chromatography with mass spectrometric detection.

    Science.gov (United States)

    Zygler, Agata; Wasik, Andrzej; Kot-Wasik, Agata; Namieśnik, Jacek

    2011-06-01

    An analytical procedure involving solid-phase extraction (SPE) and high-performance liquid chromatography-mass spectrometry has been developed for the determination of nine high-intensity sweeteners authorised in the EU; acesulfame-K (ACS-K), aspartame (ASP), alitame (ALI), cyclamate (CYC), dulcin (DUL), neohesperidin dihydrochalcone (NHDC), neotame (NEO), saccharin (SAC) and sucralose (SCL) in a variety of food samples (i.e. beverages, dairy and fish products). After extraction with a buffer composed of formic acid and N,N-diisopropylethylamine at pH 4.5 in ultrasonic bath, extracts were cleaned up using Strata-X 33 μm Polymeric SPE column. The analytes were separated in gradient elution mode on C(18) column and detected by mass spectrometer working with an electrospray source in negative ion mode. To confirm that analytical method is suitable for its intended use, several validation parameters, such as linearity, limits of detection and quantification, trueness and repeatibilty were evaluated. Calibration curves were linear within a studied range of concentrations (r(2) ≥ 0.999) for six investigated sweeteners (CYC, ASP, ALI, DUL, NHDC, NEO). Three compounds (ACS-K, SAC, SCL) gave non-linear response in the investigated concentration range. The method detection limits (corresponding to signal-to-noise (S/N) ratio of 3) were below 0.25 μg mL(-1) (μg g(-1)), whereas the method quantitation limits (corresponding to S/N ratio of 10) were below 2.5 μg mL(-1) (μg g(-1)). The recoveries at the tested concentrations (50%, 100% and 125% of maximum usable dose) for all sweeteners were in the range of 84.2 ÷ 106.7%, with relative standard deviations sweeteners in drinks, yoghurts and fish products. The procedure described here is simple, accurate and precise and is suitable for routine quality control analysis of foodstuffs. PMID:21465096

  18. Enzyme-assisted extraction and ionic liquid-based dispersive liquid-liquid microextraction followed by high-performance liquid chromatography for determination of patulin in apple juice and method optimization using central composite design.

    Science.gov (United States)

    Mohammadi, Abdorreza; Tavakoli, Rouya; Kamankesh, Marzieh; Rashedi, Hamid; Attaran, Abdolmohammad; Delavar, Mostafa

    2013-12-01

    A simple and highly sensitive analytical methodology for isolation and determination of patulin in apple-juice samples, based on enzyme-assisted extraction (EAE) and ionic liquid-based dispersive liquid-liquid microextraction (IL-DLLME) was developed and optimized. Enzymes play essential roles in eliminating interference and increasing the extraction efficiency of patulin. Apple-juice samples were treated with pectinase and amylase. A mixture of 80 μL ionic liquid and 600 μL methanol (disperser solvent) was used for the IL-DLLME process. The sedimented phase was analyzed by high-performance liquid chromatography (HPLC). Experimental parameters controlling the performance of DLLME, were optimized using response surface methodology (RSM) based on central composite design (CCD). Under optimum conditions, the calibration curves showed high levels of linearity (R(2)>0.99) for patulin in the range of 1-200 ng g(-1). The relative standard deviation (RSD) for the seven analyses was 7.5%. The limits of detection (LOD) and limits of quantification (LOQ) were 0.15 ng g(-1) and 0.5 ng g(-1), respectively. The merit figures, compared with other methods, showed that new proposed method is an accurate, precise and reliable sample-pretreatment method that substantially reduces sample matrix interference and gives very good enrichment factors and detection limits for investigation trace amount of patulin in apple-juice samples.

  19. A simple high-performance liquid chromatography for the determination of linezolid in human plasma and saliva.

    Science.gov (United States)

    Hara, Shuuji; Uchiyama, Masanobu; Yoshinari, Masami; Matsumoto, Taichi; Jimi, Shiro; Togawa, Atsushi; Takata, Tohru; Takamatsu, Yasushi

    2015-09-01

    Linezolid is an antimicrobial agent for the treatment of multiresistant Gram-positive infections. A practical high-performance liquid chromatography method was developed for the determination of linezolid in human plasma and saliva. Linezolid and an internal standard (o-ethoxybenzamide) were extracted from plasma and saliva with ethyl acetate and analyzed on a Capcell Pak C18 MG column with UV detection at 254 nm. The calibration curve was linear through the range 0.5-50 µg/mL using a 200 μL sample volume. The intra- and interday precisions were all saliva. The accuracies ranged from 98.8 to 110% for both matrices. The mean recoveries of linezolid were 80.8% for plasma and 79.0% for saliva. This method was used to determine the plasma and saliva concentrations of linezolid in healthy volunteers who were orally administered a 600 mg dose of linezolid. Our liquid-liquid extraction procedure is easy and requires a small volume of plasma or saliva (200 μL). This small volume can be advantageous in clinical pharmacokinetic studies, especially if children participate.

  20. A high-performance liquid chromatography-based radiometric assay for acyl-CoA:alcohol transacylase from jojoba.

    Science.gov (United States)

    Garver, W S; Kemp, J D; Kuehn, G D

    1992-12-01

    Acyl-CoA:alcohol transacylase catalyzes the final step in the biosynthesis of storage liquid wax esters from acyl-CoA fatty acids and fatty alcohols in a limited number of microbes, algae, and Simmondsia chinensis Link (jojoba). An improved and automated method of enzyme assay for this catalyst from cotyledons of jojoba is described. The assay method uses reversed-phase C18 high performance liquid chromatography (HPLC) to separate the labeled C30:1 liquid wax product, [14C]-dodecanyl-octadecenoate, from the unreacted substrate, [14C]octadecenoyl-CoA (oleyl-CoA), and other components produced from enzymes present in the crude homogenate of jojoba cotyledons, including [14C]-octadecenoic acid (oleic acid) and [14C]octadecenol (oleyol). Methods are also described for microscale chemical synthesis in one vessel of 14C-radiolabeled substrates and products for the transacylase. These labeled reagents are required to confirm the HPLC separations of reaction products. The radioactive components are quantitated using an on-line flow-through scintillation detector enabling sensitive and precise analysis of the reaction products.

  1. Evaluation of transfer rates of multiple pesticides from green tea into infusion using water as pressurized liquid extraction solvent and ultra-performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Chen, Hongping; Pan, Meiling; Liu, Xin; Lu, Chengyin

    2017-02-01

    Pesticide residues could be transferred from tea into its infusion and by-products, and subsequently consumed by humans. Extra extraction conditions may induce more pesticide leaching into the infusion and by-products of tea and cause greater damage to humans. The aim of this study is to evaluate the infusion of multiple pesticides from green tea into hot water via pressurized liquid extraction. The results showed that pesticides in spiked samples generally have higher leaching (0.8-45.0%) than those in the positive samples. There was a marked rise of transfer rates when water solubility increased from 20mgL(-1) to 450mgL(-1) and LogKow decreased from 6 to 4. All pesticides had more leaching into hot water using pressurized liquid extraction than traditional tea brewing. This study helps in risk assessment of pesticide residues and in the formulation of maximum residue levels (MRLs) in tea and its by-products. PMID:27596385

  2. 液相色谱-串联质谱法测定植物源性食品中16种氨基甲酸酯类农药及其代谢物%Determination of 16 carbamate pesticides and metabolite residues in plant-derived foodstuffs by high pressure liquid chromatography-tandem mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    王敬; 陈瑞春; 郭春海; 窦彩云

    2013-01-01

    目的:建立液相色谱-串联质谱法测定植物源性食品中16种氨基甲酸酯类农药及其代谢物(涕灭威、涕灭威亚砜、涕灭威砜、灭害威、恶虫威、甲萘威、克百威、乙霉威、仲丁威、茚虫威、异丙威、灭多威、速灭威、杀线威、抗蚜威和残杀威)残留量的方法。方法样品用0.1%冰醋酸-乙腈提取,提取液经过滤、浓缩后用石墨化炭黑/氨基固相萃取柱净化,采用多反应监测(multi-reaction monitoring, MRM)正离子扫描模式进行准确的定性和定量分析。结果16种氨基甲酸酯类农药在5~500 ng/mL浓度范围内均呈良好线性。16种农药在苹果、菠菜、山药、大米、大豆和生姜6种基质中的检出限和定量下限为2.0µg/kg和5.0µg/kg,在低、中、高3个水平的加标回收率为71.0%~108.0%之间, RSDs (relative standard deviations)为2.03%~11.30%。结论该方法简单快速,其灵敏度、准确度和精密度均能满足农药残留分析的要求。%Objective To establish a high pressure liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for determination 16 kinds of carbamate pesticides and their metabolites (aldicarb, al-dicarb-sulfoxide, aldicarb-sulfone, aminocarb, bendicarb, carbaryl, carbofuran, diethofencarb, fenobucarb, in-doxacarb, isoprocarb, methomyl, metolcarb, oxamyl, pirimicarb and propoxur) in plant-derived foodstuffs. Methods Samples were extracted with 0.1%formic acid-acetonitrile solution. After concentrated, the solution was cleaned up with solid-phase extraction (SPE) column of envi-Carb/NH2, the mode of multi-reaction moni-toring positive ion scanning was adopted for both the quantitative and qualitative analyses. Results Calibra-tion curves showed a good linearity over the range of 5~500 ng/mL. The limits of detection (LOD) were 2.0 µg/kg and the limits of quantification (LOQ) were 5.0 µg/kg for all the 16 pesticides spiked in apple, spinach, Chinese yam, rice, soybean and ginger

  3. Development for sound velocity and density measurements of liquid metal at high pressures

    Science.gov (United States)

    Terasaki, H.; Nishida, K.; Urakawa, S.; Uesugi, K.; Takubo, Y.; Kuwabara, S.; Nakatsuka, A.; Hoshino, M.; Kono, Y.; Higo, Y.; Kondo, T.

    2012-12-01

    Sound velocity and density of liquid Fe-alloys under high pressure is quite important physical property to estimate the amount of light elements in the terrestrial core from the seismic data. Here, we have developed the system for simultaneous measurement of sound velocity and density combined with X-ray tomography technique at high pressure and temperature. High pressure experiments were performed using 80-ton uni-axial press (Urakawa et al. 2010) installed at X-ray computed micro-tomography (CT) beamline (BL20B2), SPring-8 synchrotron radiation facility. High pressure was generated using opposed-type cupped anvils. We measured the sound velocity and density of solid FeSi at room temperature and those of solid and liquid Ni-S at high temperature. Experimental pressure was obtained from the volume of h-BN. CT measurement was carried out by rotating the press from 0 to 180o with 0.2-0.3o steps. Monochromatized X-ray of 51 keV was used. Density was determined by using X-ray absorption method based on the X-ray radiograph image. The sample thickness for the X-ray path can be directly obtained from the CT data. This is a big advantage for CT measurement. Sound velocity was measured using pulse-echo overlapping ultrasonic method. P-wave signals were generated and detected by LiNbO3 transducer attached backside of the anvil. We have successfully observed both P-wave and S-wave signals up to 1.5 GPa and 1673 K. We detected change of signal intensity and shape corresponding to melting of Ni-S sample.

  4. Fingerprint chromatogram analysis of Pseudostellaria heterophylla (Miq.) Pax root by high performance liquid chromatography.

    Science.gov (United States)

    Han, Chao; Chen, Junhui; Chen, Bo; Lee, Frank Sen-Chun; Wang, Xiaoru

    2006-09-01

    A simple and reliable high performance liquid chromatographic (HPLC) method has been developed and validated for the fingerprinting of extracts from the root of Pseudostellaria heterophylla (Miq.) Pax. HPLC with gradient elution was performed on an authentic reference standard of powdered P. heterophylla (Miq.) Pax root and 11 plant samples of the root were collected from different geographic locations. The HPLC chromatograms have been standardized through the selection and identification of reference peaks and the normalization of retention times and peak intensities of all the common peaks. The standardized HPLC fingerprints show high stability and reproducibility, and thus can be used effectively for the screening analysis or quality assessment of the root or its derived products. Similarity index calculations based on cosine angle values or correlation methods have been performed on the HPLC fingerprints. As a group, the fingerprints of the P. heterophylla (Miq.) Pax samples studied are highly correlated with closely similar fingerprints. Within the group, the samples can be further divided into subgroups based on hierarchical clustering analysis (HCA). Sample grouping based on HCA coincides nicely with those based on the geographical origins of the samples. The HPLC fingerprinting techniques thus have high potential in authentication or source-tracing types of applications.

  5. A Rough Guide to Metabolite Identification Using High Resolution Liquid Chromatography Mass Spectrometry in Metabolomic Profiling in Metazoans

    Directory of Open Access Journals (Sweden)

    David G Watson

    2013-01-01

    Full Text Available Compound identification in mass spectrometry based metabolomics can be a problem but sometimes the problem seems to be presented in an over complicated way. The current review focuses on metazoans where the range of metabolites is more restricted than for example in plants. The focus is on liquid chromatography with high resolution mass spectrometry where it is proposed that most of the problems in compound identification relate to structural isomers rather than to isobaric compounds. Thus many of the problems faced relate to separation of isomers, which is usually required even if fragmentation is used to support structural identification. Many papers report the use of MS/MS or MS2 as an adjunct to the identification of known metabolites but there a few examples in metabolomics studies of metazoans of complete structure elucidation of novel metabolites or metabolites where no authentic standards are available for comparison.

  6. Quantitative analysis of triglyceride species of vegetable oils by high performance liquid chromatography via a flame ionization detector.

    Science.gov (United States)

    Phillips, F C; Erdahl, W L; Schmit, J A; Privett, O S

    1984-11-01

    A method for the quantitative analysis of triglyceride species composition of vegetable oils by reversed-phase high performance liquid chromatography (RP-HPLC) via a flame ionization detector (FID) is described. Triglycerides are separated into molecular species via Zorbax chemically bonded octadecylsilane (ODS) columns using gradient elution with methylene chloride in acetonitrile. Identification of species is made by matching the retention times of the peaks in the chromatogram with the order of elution of all of the species that could be present in the sample on the basis of a random distribution of the fatty acids and comparison of experimental and calculated theoretical carbon numbers (TCN). Quantitative analysis is based on a direct proportionality of peak areas. Differences in the response of individual species were small and did not dictate the use of response factors. The method is applied to cocoa butter before and after randomization, soybean oil and pure olive oil.

  7. Characterisation of honeys according to their content of phenolic compounds using high performance liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Sergiel, Iwona; Pohl, Pawel; Biesaga, Magdalena

    2014-02-15

    A simple, fast and specific high performance liquid chromatography separation with an electro-spray ionisation tandem mass spectrometry detection in a negative single reaction ion monitoring scan mode was developed and used for the characterization of Polish honeys according to the content of phenolic acids, including caffeic, chlorogenic, p-coumaric, ferulic, homogentisic, p-hydroxybenzoic and vanillic acids, and flavonoids, i.e., apigenin, genistein, hesperetin, kaempferol, luteolin, rhamnetin, rutin, tricetin and quercetin. Target compounds were isolated and pre-concentrated from the honey matrix by means of the solid phase extraction using Strata X (500mg) cartridges. Analysed honeys did not contain tricetin and genistein. Hesperetin was determined for the first time in heather and linden honeys while rutin in rape honey. PMID:24128495

  8. A strategy for screening antioxidants in Ginkgo biloba extract by comprehensive two-dimensional ultra high performance liquid chromatography.

    Science.gov (United States)

    Guo, Ru-Zhou; Liu, Xin-Guang; Gao, Wen; Dong, Xin; Fanali, Salvatore; Li, Ping; Yang, Hua

    2015-11-27

    Recently, screening of bioactive compounds by on-line ultra-high performance liquid chromatography (UHPLC) draws increasing attentions for the advantages of rapidity and intuition. Nevertheless, most on-line methods were limited to the shortcoming like low resolution and peak capacity, which could interfere the active ingredient identification. Comprehensive two-dimensional UHPLC (LC×LC) has revealed to be a powerful tool to separate complex mixtures. Herein, a strategy based on LC×LC analysis coupled with pre-column 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay was proposed to screen the antioxidants from the extract of Ginkgo biloba (EGB). A total of 61 compounds were identified in EGB, and 25 of them showed appreciable radical scavenging capacity. This work may offer pharmacodynamics base for further research about EGB, also the strategy is likelihood to be applied in screening antioxidant in other herbal medicine. PMID:26477520

  9. Use of on-site high performance liquid chromatography to evaluate the magnitude and extent of organic contaminants in aquifers

    Science.gov (United States)

    Goerlitz, D.F.; Franks, B.J.

    1989-01-01

    Appraisal of ground water contaminated by organic substances raises problems of difficult sample collection and timely chemical analysis. High-performance liquid chromatography was evaluated for on-site determination of specific organic contaminants in ground water samples and was used at three study sites. Organic solutes were determined directly in water samples, with little or no preparation, and usually in less than an hour after collection. This information improved sampling efficiency and was useful in screening for subsequent laboratory analysis. On two occasions, on-site analysis revealed that samples were undergoing rapid change, with major solutes being upgraded and alteration products being formed. In addition to sample stability, this technique proved valuable for monitoring other sampling factors such as compositional changes with respect to pumping, filtration, and cross contamination. -Authors

  10. Identification of phosphorylation sites of proteins by high performance liquid chromatography-electrospray ionization-quadrupole ion trap mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    车发云; 邵晓霞; 夏其昌

    2000-01-01

    The phosphorylation sites of two phosphorylated proteins, bovine β-casein and myelin basic protein (MBP), were identified by high performance liquid chromatography-electrospray ionization-quadrupole ion trap mass spectrometry (HPLC-ESI-QITMS). The tryptic digest of each protein was separated by HPLC, the molecular weight of each peptide was determined by ESI-QITMS on line, and MS/MS spectrum of each peptide was simultaneously obtained by the combination of collision-induced desorption (CID) technique and tandem mass spectrometry (MS/MS) of QITMS. The phosphorylated peptide was identified by looking into whether the difference between the observed and predicted molecular weights of a peptide is 80 u or its integral multiple. Then the phosphorylation site was identified through manual interpretation of the MS/MS spectrum of the phosphorylated peptide or automatic SEQUEST data base-searching.

  11. Molecular and nanoparticle postcolumn reagents for assay of low-molecular-mass biothiols using high-performance liquid chromatography.

    Science.gov (United States)

    Zu, Yanbing

    2009-10-15

    Determination of low-molecular-mass (LMM) biothiols in biological matrixes is of importance in the studies of their related bio-processes and for the clinical diagnostics of a variety of diseases. Standard method for the assay of the small biothiols is in demand. Postcolumn techniques used in high-performance liquid chromatography (HPLC) allow automation of the derivatization step and, therefore, are suitable for standardization of HPLC analysis. This paper gives an overview of the existing reaction systems useful for the postcolumn assay of the LMM biothiol molecules in conjunction with HPLC. The postcolumn reagents are classified by the types of their reactions with thiol-containing compounds. The chemical reactivity and selectivity as well as the spectroscopic characteristics of the postcolumn reagents have been addressed. The emerging strategies of using nanoparticles as thiol-reactive reagents and their applications in postcolumn detection of the LMM biothiols have also been discussed in detail. PMID:19442593

  12. Determination of biogenic amines in squid and white prawn by high-performance liquid chromatography with postcolumn derivatization.

    Science.gov (United States)

    Zhao, Qing-Xi; Xu, Jie; Xue, Chang-Hu; Sheng, Wen-Jing; Gao, Rui-Chang; Xue, Yong; Li, Zhao-Jie

    2007-04-18

    A simple method was developed for the determination of biogenic amines in aquatic food products using a reverse-phase high-performance liquid chromatography with postcolumn automatic o-phthalaldehyde derivatization and fluorescence detection. The linearity, repeatability, and recovery of the method for seven amines (tyramine, putrescine, cadaverine, histamine, agmatine, spermidine, and spermine) were evaluated. This optimized method was applied to detect biogenic amines in squid and white prawn during refrigerated storage. Sensory analysis, pH value, and total volatile base nitrogen value were combined to evaluate the freshness quality of these two raw materials. Agmatine and cadaverine in squid, cadaverine, and putrescine in white prawn were the most obviously changed amines during the storage at two different temperatures, and these biogenic amines could be the effective quality indicators for the freshness of the raw aquatic materials. PMID:17381105

  13. IDENTIFICATION OF MYCOBACTERIUM GENAVENSE IN A DIANA MONKEY (CERCOPITHECUS DIANA) BY POLYMERASE CHAIN REACTION AND HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY.

    Science.gov (United States)

    Kelly, Kathleen M; Wack, Allison N; Bradway, Dan; Simons, Brian W; Bronson, Ellen; Osterhout, Gerard; Parrish, Nicole M; Montali, Richard J

    2015-06-01

    A 25-yr-old Diana monkey (Cercopithecus diana) with a 1.5-yr history of chronic colitis and diarrhea was found to have disseminated granulomatous disease with intralesional acid fast bacilli. Bacilli were identified as Mycobacterium genavense by polymerase chain reaction, sequencing of the 16S-23S ribosomal RNA intergenic spacer (ITS) gene, and mycolic acid analysis by high-performance liquid chromatography. Mycobacterium genavense is a common cause of mycobacteriosis in free-ranging and captive birds. In addition, recognition of opportunistic infection in human immunodeficiency virus-positive patients is increasing. Disease manifestations of M. genavense are similar to Mycobacterium avium complex (MAC) and include fever, wasting, and diarrhea with disseminated disease. Similar clinical signs and lesions were observed in this monkey. Mycobacterium genavense should be considered as a differential for disseminated mycobacterial disease in nonhuman primates as this agent can mimic MAC and related mycobacteria.

  14. Automated direct assay system for RU38486, an antiprogesterone-antiglucocorticoid agent, and its metabolites using high performance liquid chromatography.

    Directory of Open Access Journals (Sweden)

    Nagoshi,Kazusuke

    1991-04-01

    Full Text Available An automated direct assay system using high performance liquid chromatography was developed for the measurement of RU38486 and its three metabolites (RU42698, RU42848, RU42633 in human serum. Serum concentrations of these compounds were measured up to 144 h following single oral administration of 200 (200 mg group, n = 3 or 400 mg (400 mg group, n = 3 of RU38486 to healthy female volunteers. The serum half-lives (200 mg group-400 mg group of RU38486, RU42698, RU42848 and RU42633 were 31.8-33.1 h, 41.2-39.3 h, 33.9-36.6 h and 29.2-36.6 h, respectively. Our system could quantify them easily and simultaneously, and was considered to be valuable in studies on the relationship between the pharmacokinetics and the clinical effects of RU38486.

  15. Enantioselective and diastereoselective separation of synthetic pyrethroid insecticides on a novel chiral stationary phase by high-performance liquid chromatography.

    Science.gov (United States)

    Tan, Xulin; Hou, Shicong; Wang, Min

    2007-07-01

    A novel chiral packing material for high-performance liquid chromatography (HPLC) was prepared by connecting (R)-1-phenyl-2-(4-methylphenyl) ethylamine (PTE) amide derivative of (S)-isoleucine to aminopropyl silica gel through 2-amino-3,5-dinitro-1-carboxamido-benzene unit. This chiral stationary phase was applied to the enantioselective and diastereoselective separation of five pyrethroid insecticides by HPLC under normal phase condition. To achieve satisfactory baseline separation an optimization of the variables of mobile phase composition was required. The two enantiomers of fenpropathrin and four stereoisomers of fenvalerate were baseline separated using hexane-1,2-dichloroethane-2-propanol as mobile phase. The results show that the enantioselectivity of CSP is better than Pirkle type 1-A column for these compounds. Only partial separations for the cypermethrin and cyfluthrin stereoisomers were observed. Seven peaks and eight peaks were observed for cypermethrin and cyfluthrin, respectively. The elution orders were assigned by using different stereoisomer-enriched products.

  16. Analytical method by high resolution-liquid chromatography for assay of 2 g Clonazepam tablets disolution without lactose

    International Nuclear Information System (INIS)

    A valid method was developed to assess 2 mg Clonazepam tablets disolution without lactose by high-performance liquid chromatography by UV detection to 254 nm. Establishment of Clonazepam in dissolution medium was confirmed, and parameters of specificity, linearity, and accuracy were assessed, as well as influence of filtration and stability or active principle. Linearity curve was drawed in rank of 1, 2-2,6 μg/mL, with a correlation coefficient similar to 0,99418; statistical test wasn't statistically significant for interceptor and slope. In study, it was possible to demonstrate that stability or active principle in dissolution was maintained in more than double of duration of dissolution assay. (Author)

  17. [Simultaneous determination of six synthetic sweeteners in food by high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Liu, Xiaoxi; Ding, Li; Liu, Jinxia; Zhang, Ying; Huang, Zhiqiang; Wang, Libing; Chen, Bo

    2010-11-01

    A simple and sensitive method for the determination of six synthetic sweeteners (sodium cyclamate, saccharin sodium, acesulfame-K, aspartame, alitame and neotame) in food was developed. The synthetic sweeteners were extracted by methanol-water (1 : 1, v/v). The extract was separated on a C18 column using 0.1% (v/v) formic acid-5 mmol/L ammonium formate/acetonitrile as mobile phase, and then detected by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) using multiple reaction monitoring (MRM) mode. The good linearities (r > 0.998) were achieved for all the analytes over the range of 20-500 microg/L. The recoveries obtained ranged from 81.3% to 106.0% at three spiked concentrations, with the relative standard deviations lower than 11%. The established method has been successfully applied to the determination of synthetic sweeteners in food. PMID:21381416

  18. Identification of phosphorylation sites of proteins by high performance liquid chromatography-electrospray ionization-quadrupole ion trap mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The phosphorylation sites of two phosphorylated proteins, bovine b-casein and myelin basic protein (MBP), were identified by high performance liquid chromatography-electrospray ionization-quadrupole ion trap mass spectrometry (HPLC-ESI-QITMS). The tryptic digest of each protein was separated by HPLC, the molecular weight of each peptide was determined by ESI-QITMS on line, and MS/MS spectrum of each peptide was simultaneously obtained by the combination of collision-induced desorption (CID) technique and tandem mass spectrometry (MS/MS) of QITMS. The phosphorylated peptide was identified by looking into whether the difference between the observed and predicted molecular weights of a peptide is 80 u or its integral multiple. Then the phosphorylation site was identified through manual interpretation of the MS/MS spectrum of the phosphorylated peptide or automatic SEQUEST data base-searching.

  19. Retention and chiral recognition mechanism of organo-phosphorus compounds in high-performance liquid chroma-tography

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In normal phase condition, a series of chiral phosphorus organic compounds have been separated by high-performance liquid chromatography. In order to study the retention and chiral recognition mechanism, the method of quantitative structure-enantioselectivity retention relationships (QSERRs) has been investigated from the quantitative equations established between the chromatographic retention of enantiomers and their molecular descriptors of physicochemical properties. The results show that on the Pirkle-type chiral stationary phase (CSP) of Sumichiral OA4700, it is the parameter of LUMO that gives the most contribution to the chromatographic re-tention of O-ethyl O-(substituted) phenyl N-isopropyl phosphoroamidothioates resulting from the interaction of hydrogen bond and (or) p-p interaction. Meanwhile, the chiral recognition is formed from the contribution of logP and LUMO.

  20. Determination of trace mercury species by high performance liquid chromatography-inductively coupled plasma mass spectrometry after cloud point extraction.

    Science.gov (United States)

    Chen, Haiting; Chen, Jianguo; Jin, Xianzhong; Wei, Danyi

    2009-12-30

    A sensitive method for speciation analysis of inorganic mercury (Hg(2+)) and methyl mercury (MeHg(+)) has been developed by using high performance liquid chromatography (HPLC) combined with inductively coupled plasma mass spectrometry (ICP-MS) after cloud point extraction. The analytes were complexed with sodium diethyldithiocarbamate (DDTC) and preconcentrated by a non-ionic surfactant Triton X-114. Mercury species were effectively separated by HPLC in less than 6 min. The enhancement factors for 25 mL sample solution were 42 and 21, and the limits of detection were 4 and 10 ng L(-1) for Hg(2+) and MeHg(+), respectively. The developed method was successfully applied to the determination of trace amount of mercury species in environmental and biological samples.