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1

Solid-phase extraction and determination of trace elements in environmental samples using naphthalene adsorbent  

International Nuclear Information System (INIS)

Naphthalene co-precipitated with quaternary ammonium salt such as tetraoctyl ammonium bromide and methyltrioctyl ammonium chloride have been used as adsorbent for solid phase extraction of metal ions such as Hg, Cd and Fe. The metal ions are retained on the adsorbent in a column as their complexes with suitable ligands and eluted by an eluent before instrumental measurements. The optimization of the procedures for solid phase extraction and consequent determination of trace elements and application to environmental samples especially water samples will be discussed. (author)

2

New macroporous ?-cyclodextrin functionalized ionic liquid polymer as an adsorbent for solid phase extraction with phenols.  

Science.gov (United States)

Cyclodextrin-ionic liquid polymer (?CD-BIMOTs-TDI) is a new class of macroporous material and has great potential to be used as an SPE adsorbent material for extraction of phenols in river water samples. Six phenols, as model analytes, were extracted on a ?CD-BIMOTs-TDI SPE cartridge, and then, eluted with 2 mL of methanol containing 1% acetic acid. The optimum experimental condition was 15 mL of sample volume (sample at pH 6) and 2 mL of methanol containing 1% acetic acid as an eluent solvent. The eluent concentration was determined by using Gas Chromatography-Flame Ionization Detector (GC-FID). Under optimized condition, high sensitivity (detection limits 0.23-0.35 µg/L) and good recoveries (87-116%) were achieved with satisfactory relative standard deviation (RSD) (0.1-1.7%). The developed ?CD-BIMOTs-TDI-SPE was then compared with other adsorbents, and the obtained results showed that the ?CD-BIMOTs-TDI exhibited higher extraction recovery due to the unique structure and properties. Finally, the ?CD-BIMOTs-TDI was applied as a solid phase extraction sorbent for phenols determination under optimized condition, in river and tap waters, prior to the GC-FID separation. PMID:25159393

Raoov, Muggundha; Mohamad, Sharifah; bin Abas, Mhd Radzi; Surikumaran, Hemavathy

2014-12-01

3

Solid phase extraction membrane  

Science.gov (United States)

A wet-laid, porous solid phase extraction sheet material that contains both active particles and binder and that possesses excellent wet strength is described. The binder is present in a relatively small amount while the particles are present in a relatively large amount. The sheet material is sufficiently strong and flexible so as to be pleatable so that, for example, it can be used in a cartridge device.

Carlson, Kurt C [Nashville, TN; Langer, Roger L [Hudson, WI

2002-11-05

4

Solid phase extraction of Zn as xylenol orange complex on naphthalene adsorbent and its determination by Flame Atomic Absorption Spectrometry  

International Nuclear Information System (INIS)

A solid-phase extraction method for determination of zinc by FAAS has been described. The proposed procedure was based on adsorption of zinc-xylenol orange complex on naphthalene methyltrioctyl ammonium chloride adsorbent on a column. The adsorbed metal complex was eluted from the column with nitric acid solution and determined by FAAS. Adsorption conditions including pH, reagent concentration, sample volume, flow rate, and concentration of interfering ions were investigated. Calibration plot was linear in 1?50 ng mL-1 concentration range of Zn in the initial solution, r = 0.9999. Limit of detection was calculated based on 3Sb criterion and equaled 0.60 ng mL-1 when 100 mL-in-volume samples were used, and 0.06 ng mL-1 in case of 1000 mL-in-volume samples. Relative standard deviation for ten replicate determinations of 5 and 20 ng mL-1 Zn was 3.8 and 1.1%, respectively. The proposed method was applied to determination of zinc in mineral and tap water samples, as well as in sodium sulfite salt from Merck. (authors)

5

Carboxyl modified multi-walled carbon nanotubes as solid-phase extraction adsorbents combined with high-performance liquid chromatography for analysis of linear alkylbenzene sulfonates.  

Science.gov (United States)

Recently, multi-wall carbon nanotubes (MWCNTs) as adsorbents of solid-phase extraction are attractive because they can be used for enrichment of organic compounds and metal ions at trace levels. In this study, we use the carboxyl modified multi-wall carbon nanotubes (CMMWCNTs) as adsorbents of solid-phase extraction for extraction of linear alkylbenzene sulfonates (LAS), which are widely used anion surfactant with different homologues, and detected by HPLC-UV. The effect of eluent and its volume, sample pH and flow rate, sample volume and the ultrasonic time of sample, the content of the electrolyte (NaCl) were investigated and optimized. The detection limit for LAS homologues was 0.02-0.03microgL(-1) with R.S.D. (n=6) ranging from 2.04 to 10.03%. The recoveries of LAS homologues in the spiked environmental water samples ranged from 84.8 to 106.1%. The proposed method has been applied successfully to the analysis of LAS in aqueous environmental samples, which demonstrates that CMMWCNTs-based solid-phase extraction is a precision and convenient enrichment method and can be used for analysis of LAS homologues in water samples. PMID:18809077

Guan, Zhuo; Huang, Yuming; Wang, Weidong

2008-10-10

6

N-methylimidazolium modified magnetic particles as adsorbents for solid phase extraction of genomic deoxyribonucleic acid from genetically modified soybeans.  

Science.gov (United States)

N-Methylimidazolium modified magnetic particles (MIm-MPs) were prepared and applied in the solid phase extraction of genomic deoxyribonucleic acid (DNA) from genetically modified soybeans. The adsorption of MIm-MPs for DNA mainly resulted from the strong electrostatic interaction between the positively charged MPs and the negatively charged DNA. The elution of DNA from MPs-DNA conjugates using phosphate buffer resulted from the stronger electrostatic interaction of phosphate ions with MPs than DNA. In the extraction procedure, no harmful reagents (e.g. phenol, chloroform and isopropanol, etc.) used, high yield (10.4 ?g DNA per 30 mg sample) and high quality (A260/A280=1.82) of DNA can be realized. The as-prepared DNA was used as template for duplex-polymerase chain reaction (PCR) and the PCR products were analyzed by a sieving capillary electrophoresis method. Quick and high quality extraction of DNA template, and fast and high resolution detection of duplex PCR products can be realized using the developed method. No toxic reagents are used throughout the method. PMID:23522109

Deng, Manchen; Jiang, Cheng; Jia, Li

2013-04-10

7

Eggshell membrane-based biotemplating of mixed hemimicelle/admicelle as a solid-phase extraction adsorbent for carcinogenic polycyclic aromatic hydrocarbons.  

Science.gov (United States)

A new solid-phase extraction (SPE) format was demonstrated, based on eggshell membrane (ESM) templating of the mixed hemimicelle/admicelle of linear alkylbenzenesulfonates (LAS) as an adsorbent for the enrichment of carcinogenic polycyclic aromatic hydrocarbons (PAHs) in environmental aqueous samples. The LAS mixed hemimicelle/admicelle formation and SPE of the target PAHs were conducted simultaneously by adding the organic target and LAS through a column filled with 500 mg of ESM. The effect of various factors, including LAS concentration, solution pH, ionic strength, and humic acid concentration on the recoveries of PAHs were investigated and optimized. The results showed that LAS concentration and solution pH had obvious effect on extraction of PAHs, and the recoveries of PAHs compounds decreased in the presence of salt and humic acid. Under the optimized analytical conditions, the present method could respond down to 0.1-8.6 ng/L PAHs with a linear calibration ranging from 0.02 to 10 ?g/L, showing a good PAHs enrichment ability with high sensitivity. The developed method was used satisfactorily for the detection of PAHs in environmental water samples. The mixed hemimicelle/admicelle adsorbent exhibited high extraction efficiency to PAHs and good selectivity with respect to natural organic matter and was advantageous over commercial C18 adsorbent, for example, high extraction yield, high breakthrough volume, and easy regeneration. PMID:25025712

Wang, Weidong; Chen, Bo; Huang, Yuming

2014-08-13

8

Solid Phase Micro Extraction (SPME)  

Science.gov (United States)

Internation Flavors and Fragrances Inc. proprietary research technology, Solid Phase Micro Extraction (SPME) utilizes a special fiber needle placed directly next to the bloom of the living flower to collect the fragrance molecules. SPME was used in the Space Flower experiment aboard STS-95 space shuttle mission, after which Dr. Braja Mookherjee (left) and Subha Patel of IFF will analyze the effects of gravity on the Overnight Scentsation rose plant.

1998-01-01

9

[Simultaneous determination of 16 organophosphorous pesticides in vegetables, fruits and tea by gas chromatography coupled with clean-up by mesoporous alumina as solid-phase extraction adsorbent].  

Science.gov (United States)

A gas chromatographic method based on solid-phase extraction was developed for the simultaneous determination of 16 organophosphorous pesticides in vegetables, fruits and tea, including cabbage, lettuce, pumpkin, onion, tomato, turnip, apple, pear and tea. The samples were extracted with ethyl acetate, and clean-up with mesoporous alumina as solid-phase extraction adsorbent. The separation of target compounds was performed on a DB-1701 capillary column, and the quantitative analysis of the organophosphorous pesticides was carried out by gas chromatography with flame photometric detection. The results showed that the calibration curves of the 16 organophosphorous pesticides were linear in the range of 10-2 000 microg/L with good correlation coefficients (R2 > 0.997). The recoveries of the pesticides in different samples at three spiked levels ranged from 83.2% to 103.8% with the relative standard deviations of 2.0%-9.9%. This method has high sensitivity, high accuracy and good repeatability, and can be applied to the determination of the organophosphorus pesticide residues in vegetables, fruits and tea. PMID:25255574

Hu, Yeqin; Xi, Cunxian; Cao, Shurui; Wang, Guomin; Li, Xianliang; Zhang, Lei; Zhang, Yunhuai

2014-07-01

10

Synthesis, characterization, and application of polystyrene adsorbents containing tri-n-butylphosphate for solid-phase extraction of uranium (VI) from aqueous nitrate solutions  

International Nuclear Information System (INIS)

Polystyrene adsorbent for solid-phase extraction of U(VI) was developed through in situ copolymerization of styrene and divinylbenzene in the presence of tri-n-butylphosphate and its magnetic form was obtained by addition of fine particles of magnetite in an amount of 15 wt% of the total monomers used. The obtained adsorbents were characterized by means of scanning electron microscope, FTIR spectroscopy and X-ray powder diffraction. The adsorption behavior of U(VI) from aqueous nitrate solutions onto non-magnetic adsorbent RI (St-DVB-TBP) and its magnetic form RII (St-DVB-TBP-Fe3O4) at different experimental condition was studied using batch method. The adsorption results were found to fit Langmuir model. The magnetite-containing adsorbent showed higher uptake values relative to the corresponding magnetite-free one. The adsorption of U(VI) onto RI followed pseudo-first order kinetics whereas the adsorption onto RII followed pseudo-second order. Thermodynamic studies revealed that the adsorption process was a spontaneous exothermic reaction. Desorption of the loaded U(VI) was carried out using distilled water and found to be 97 and 93 % for RI and RII, respectively. (author)

11

Silica gel-polyethylene glycol as a new adsorbent for solid phase extraction of cobalt and nickel and determination by flame atomic absorption spectrometry.  

Science.gov (United States)

In this paper a novel solid phase extraction method to determine Co(II) and Ni(II) using silica gel-polyethylene glycol (Silica-PEG) as a new adsorbent is described. The method is based on the adsorption of cobalt and nickel ions in alkaline media on polyethylene glycol-silica gel in a mini-column, elution with nitric acid and determination by flame atomic absorption spectrometry. The adsorption conditions such as NaOH concentration, sample volume and amount of adsorbent were optimized in order to achieve highest sensitivity. The calibration graph was linear in the range of 0.5-200.0ngmL(-1) for Co(II) and 2.0-100.0ngmL(-1) for Ni(II) in the initial solution. The limit of detection based on 3S(b) was 0.37ngmL(-1) for Co(II) and 0.71ngmL(-1) for Ni(II). The relative standard deviations (R.S.D.) for ten replicate measurements of 40ngmL(-1) of Co(II), and Ni(II) were 3.24 and 3.13%, respectively. The method was applied to determine Co(II) and Ni(II) in black tea, rice flour, sesame seeds, tap water and river water samples. PMID:20298852

Pourreza, N; Zolgharnein, J; Kiasat, A R; Dastyar, T

2010-05-15

12

Ionic liquid-modified magnetic polymeric microspheres as dispersive solid phase extraction adsorbent: a separation strategy applied to the screening of sulfamonomethoxine and sulfachloropyrazine from urine.  

Science.gov (United States)

Ionic liquid-modified magnetic polymeric microspheres (ILMPM) were prepared based on Fe3O4 magnetic nanoparticles (MNPs) and ionic liquids (ILs) incorporated into a polymer. The composites were characterized using scanning electron microscopy, Fourier transform infrared analysis, thermogravimetric analysis, X-ray diffraction, and vibrating magnetometer, which indicated that ILMPM had a regularly spherical shape and strong magnetic property. The obtained ILMPM were successfully applied as a special adsorbent of magnetic dispersive solid phase extraction (MDSPE) for the rapid extraction and isolation of sulfamonomethoxine sodium and sulfachloropyrazine sodium in urine. The factors that affected extraction efficiency, such as adsorption conditions, desorption conditions, washing and elution solvents, and pH of the sample solution, were optimized. Under the optimum condition, good linearity in the range of 0.005-2.0 ?g g(-1) (r???0.9996) was obtained for the two sulfonamides (SAs); the average recoveries at three spiked levels ranged from 86.9 to 102.1 %, with relative standard deviations of ?4.3 %. The presented ILMPM-MDSPE method combined the advantages of ILs, MNPs, and MDSPE and therefore could be potentially applied for rapid screening of SAs in urine. PMID:24573579

Yan, Hongyuan; Gao, Mengmeng; Yang, Chen; Qiu, Mande

2014-04-01

13

Using Zn/Al layered double hydroxide as a novel solid-phase extraction adsorbent to extract polycyclic aromatic hydrocarbons at trace levels in water samples prior to the determination of gas chromatography-mass spectrometry  

Energy Technology Data Exchange (ETDEWEB)

This paper demonstrates, for the first time, the great potential of using Zn/Al layered double hydroxide intercalated sodium dodecyl benzene sulfonate (Zn/Al-SDBS-LDH) as a solid-phase extraction (SPE) material in the extraction of persistent organic pollutants prior to the determination of gas chromatography-mass spectrometry in environmental water samples. Zn/Al-SDBS-LDH, a relatively inexpensive and simply prepared material, was synthesized and used as a SPE adsorbent to quantitatively determine the concentration of five polycyclic aromatic hydrocarbons (PAHs) in environmental water samples. Factors affecting extraction efficiency, such as, eluent type, eluent volume, flow rate of sample, sample volume, and amount of adsorbent, were investigated and optimized in detail. Experimental results indicate that there is an excellent linear relationship between peak area and the concentration of PAHs over the range of 5-500 ng L{sup -1}, and the precisions (relative standard deviation (RSD)) were 2.5-6.3 % under the optimum conditions. Based on the ratio of chromatographic signal-to-base line noise (S/N = 3), the limits of detection could reach 1.2-3.2 ng L{sup -1}. This novel method was successfully applied to the analysis of PAHs in environmental water samples. As such, we show here that the use of Zn/Al-SDBS-LDH as SPE adsorbent materials, coupled with gas chromatography-mass spectrometry, is an excellent improvement in the routine analysis of PAHs at trace levels in the environment. (orig.)

Liu, Yan-Long [Wuhan University of Technology, School of Resources and Environmental Engineering, Wuhan (China); Shandong Academy of Sciences, Key Laboratory for Applied Technology of Sophisticated Analytical Instruments of Shandong Province, Analysis and Test Center, Jinan (China); Zhou, Jia-Bin [Wuhan University of Technology, School of Resources and Environmental Engineering, Wuhan (China); Zhao, Ru-Song; Chen, Xiang-Feng [Shandong Academy of Sciences, Key Laboratory for Applied Technology of Sophisticated Analytical Instruments of Shandong Province, Analysis and Test Center, Jinan (China)

2012-09-15

14

Multiplexed Colorimetric Solid-Phase Extraction  

Science.gov (United States)

Multiplexed colorimetric solid-phase extraction (MC-SPE) is an extension of colorimetric solid-phase extraction (C-SPE) an analytical platform that combines colorimetric reagents, solid phase extraction, and diffuse reflectance spectroscopy to quantify trace analytes in water. In CSPE, analytes are extracted and complexed on the surface of an extraction membrane impregnated with a colorimetric reagent. The analytes are then quantified directly on the membrane surface using a handheld diffuse reflectance spectrophotometer. Importantly, the use of solid-phase extraction membranes as the matrix for impregnation of the colorimetric reagents creates a concentration factor that enables the detection of low concentrations of analytes in small sample volumes. In extending C-SPE to a multiplexed format, a filter holder that incorporates discrete analysis channels and a jig that facilitates the concurrent operation of multiple sample syringes have been designed, enabling the simultaneous determination of multiple analytes. Separate, single analyte membranes, placed in a readout cartridge create unique, analyte-specific addresses at the exit of each channel. Following sample exposure, the diffuse reflectance spectrum of each address is collected serially and the Kubelka-Munk function is used to quantify each water quality parameter via calibration curves. In a demonstration, MC-SPE was used to measure the pH of a sample and quantitate Ag(I) and Ni(II).

Gazda, Daniel B.; Fritz, James S.; Porter, Marc D.

2009-01-01

15

TiO? nanotube arrays prepared by anodization as an adsorbent in micro-solid-phase extraction to preconcentrate and determine nitrogen-containing polycyclic aromatic hydrocarbons in water samples.  

Science.gov (United States)

In this study, a simultaneous determination method for nitrogen-containing polycyclic aromatic hydrocarbons including 7-methylquinoline, acridine, 5,6-benzoquinoline, carbazole, and 9-methylcarbazole was developed. This method is based on a micro-solid phase extraction using TiO2 nanotube arrays as an adsorbent in combination with HPLC. Some factors that had an effect on the enrichment were optimized, such as sample pH, surfactant concentration, ion strength, type of eluent, equilibrium time, and desorption time. Under the optimized conditions, the linear ranges and LODs were in the range of 0.01-100 and 0.0035-0.81 ?g/L, respectively. The precisions of the proposed method were <9.51% (RSD, n = 6). The developed method was validated with four real samples, and the spiked recoveries were in the range of 77-109.6%. All these results demonstrated that this novel micro-solid-phase extraction technique was a reliable alternative to conventional preconcentration method for the extraction and analysis of such nitrogen-containing polycyclic aromatic hydrocarbons in complex samples. PMID:24510730

Zhou, Qingxiang; Fang, Zhi

2014-04-01

16

[Determination of six phthalate acid esters in camellia oil by gas chromatography-mass spectrometry coupled with solid-phase extraction using single-walled carbon nanotubes as adsorbent].  

Science.gov (United States)

An analytical method based on solid-phase extraction with single-walled carbon nanotubes (SWCNTs) as adsorbent was developed for the simultaneous determination of six phthalate acid esters (PAEs) in camellia oil by gas chromatography-mass spectrometry (GC-MS). The samples were diluted by hexane and then cleaned up with a glass SWCNTs solid phase extraction (SPE) column. The PAEs were measured by GC-MS in selected ion monitoring (SIM) mode, using external standard method for quantitative analysis. The important factors affecting extraction efficiency, such as the dilution volume of hexane, the type of adsorbent material, the dosage of SWCNTs, the volume of wash solution, the type and volume of elution solution were optimized. The optimal conditions were as follows: the dilution volume of hexane was 5 mL, the dosage of SWCNTs was 0.6 g, the wash solution was 20 mL hexane, and the elution solution was 5 mL toluene. The six PAEs had a good linear range from 0.05 mg/L to 1.0 mg/L, with the correlation coefficients (r) all above 0.999 9. The average recoveries of the six targets in spiked camellia oil (from 0.05 mg/kg to 1.0 mg/kg) ranged from 86.4% to 111.7% with the relative standard deviations (RSDs) from 4.2% to 10.4%. The developed method is accurate, quick and suitable for the determination of the six PAEs in camellia oil. PMID:25255566

Zhang, Fan; Li, Zhonghai; Zhang, Ying; Huang, Zhiqiang; Wang, Xiaosong

2014-07-01

17

Magnetic solid phase extraction of non-ionic surfactants from water  

Energy Technology Data Exchange (ETDEWEB)

Magnetic solid phase extraction was tested for the preconcentration of non-ionic surfactants based on oxyethylated nonylphenol, aliphatic alcohols and hydrogenated fatty acid methyl esters from water. Magnetic hydrophobic adsorbents exhibited the best extraction characteristics. Surfactants with the middle oxyethylation level were extracted efficiently while the extraction of surfactants with low and high oxyethylation levels was very low.

Safarikova, Mirka [Laboratory of Biochemistry and Microbiology, Institute of Landscape Ecology, Na Sadkach 7, 370 05 Ceske Budejovice (Czech Republic)]. E-mail: mirkasaf@seznam.cz; Kibrikova, Ivanna [Laboratory of Biochemistry and Microbiology, Institute of Landscape Ecology, Na Sadkach 7, 370 05 Ceske Budejovice (Czech Republic); Ptackova, Lucie [Laboratory of Biochemistry and Microbiology, Institute of Landscape Ecology, Na Sadkach 7, 370 05 Ceske Budejovice (Czech Republic); Hubka, Tomas [Department of Analytical Chemistry, Faculty of Chemical Technology, University of Pardubice, Nam. Cs. legii 565, 532 10 Pardubice (Czech Republic); Komarek, Karel [Department of Analytical Chemistry, Faculty of Chemical Technology, University of Pardubice, Nam. Cs. legii 565, 532 10 Pardubice (Czech Republic); Safarik, Ivo [Laboratory of Biochemistry and Microbiology, Institute of Landscape Ecology, Na Sadkach 7, 370 05 Ceske Budejovice (Czech Republic)

2005-05-15

18

Magnetic solid phase extraction of non-ionic surfactants from water  

International Nuclear Information System (INIS)

Magnetic solid phase extraction was tested for the preconcentration of non-ionic surfactants based on oxyethylated nonylphenol, aliphatic alcohols and hydrogenated fatty acid methyl esters from water. Magnetic hydrophobic adsorbents exhibited the best extraction characteristics. Surfactants with the middle oxyethylation level were extracted efficiently while the extraction of surfactants with low and high oxyethylation levels was very low

19

Fe3O4@ionic liquid@methyl orange nanoparticles as a novel nano-adsorbent for magnetic solid-phase extraction of polycyclic aromatic hydrocarbons in environmental water samples.  

Science.gov (United States)

A novel nano-adsorbent, Fe3O4@ionic liquid@methyl orange nanoparticles (Fe3O4@IL@MO NPs), was prepared for magnetic solid-phase extraction (MSPE) of polycyclic aromatic hydrocarbons (PAHs) in environmental water samples. The Fe3O4@IL@MO NPs were synthesized by self-assembly of the ionic liquid 1-octadecyl-3-methylimidazolium bromide (C18mimBr) and methyl orange (MO) onto the surface of Fe3O4 silica magnetic nanoparticles, as confirmed by infrared spectroscopy, ultraviolet-visible spectroscopy and superconducting quantum interface device magnetometer. The extraction performance of Fe3O4@IL@MO NPs as a nano-adsorbent was evaluated by using five PAHs, fluorene (FLu), anthracene (AnT), pyrene (Pyr), benzo(a)anthracene (BaA) and benzo(a)pyrene (BaP) as model analytes. Under the optimum conditions, detection limits in the range of 0.1-2 ng/L were obtained by high performance liquid chromatography-fluorescence detection (HPLC-FLD). This method has been successfully applied for the determination of PAHs in environmental water samples by using the MSPE-HPLC-FLD. The recoveries for the five PAHs tested in spiked real water samples were in the range of 80.4-104.0% with relative standard deviations ranging from 2.3 to 4.9%. PMID:24401423

Liu, Xiaofei; Lu, Xin; Huang, Yong; Liu, Chengwei; Zhao, Shulin

2014-02-01

20

Solvent-assisted dispersive solid phase extraction.  

Science.gov (United States)

In this research, a novel extraction technique termed solvent-assisted dispersive solid phase extraction (SADSPE) was developed for the first time. The new method was based on the dispersion of the sorbent into the sample to maximize the contact surface. In this method, the dispersion of the sorbent at a very low milligram level was achieved by injecting a solution of the sorbent into the aqueous sample. Thereby, a cloudy solution formed. The cloudy state resulted from the dispersion of the fine particles of the sorbent in the bulk aqueous sample. After extraction, phase separation was performed by centrifugation and the enriched analyte in the sedimented phase could be determined by instrumental methods. The performance of SADSPE was illustrated with the determination of the trace amounts of cobalt(II) as a test analyte in food and environmental water samples by using flame atomic absorption spectrometry detection. Some key parameters for SADSPE, such as sorbent selection and amount, type and volume of dispersive solvent, pH, chelating agent concentration, and salt concentration, were investigated. Under the most favorable conditions, good limit of detection (as low as 0.2 µg L(-1)) and repeatability of extraction (RSD below 2.2%, n=10) was obtained. The accuracy of the method was tested with standard reference material (SRM-1643e and SRM-1640a) and spiked addition. The advantages of SADSPE method are simplicity of operation, rapidity, low cost, high recovery, and enrichment factor. PMID:24148429

Jamali, Mohammad Reza; Firouzjah, Ahmad; Rahnama, Reyhaneh

2013-11-15

 
 
 
 
21

Facile preparation of surface-exchangeable core@shell iron oxide@gold nanoparticles for magnetic solid-phase extraction: Use of gold shell as the intermediate platform for versatile adsorbents with varying self-assembled monolayers  

International Nuclear Information System (INIS)

Graphical abstract: -- Highlights: •The core@shell Fe3O4@Au nanoparticles functionalized with SAMs were successfully constructed. •The SAMs could be transformed from one kind to another via thiol exchange process. •The developed nanomaterials could be applied in mode switching MSPE. -- Abstract: The core@shell Fe3O4@Au nanoparticles (NPs) functionalized with exchangeable self-assembled monolayers have been developed for mode switching magnetic solid-phase extraction (MSPE) using high performance liquid chromatography with ultraviolet detection. The adsorbents were synthesized by chemical coprecipitation to prepare magnetic cores followed by sonolysis to produce gold shells. Functionalization of Fe3O4@Au NPs surface was realized through self-assembly of commercially available low molecular weight thiol-containing ligands using gold shells as intermediate platform and the dynamic nature of Au–S chemistry allowed substituent of one thiol-containing ligand with another simply by thiol exchange process. The resultant adsorbents were characterized by transmission electronic microscopy, Fourier transform infrared spectroscopy, elemental analysis, contact angle measurement, and vibrating sample magnetometry. To evaluate the versatile performance of the developed MSPE adsorbents, they were applied for normal-phase SPE followed by reversed-phase SPE. A few kinds of diphenols and polycyclic aromatic hydrocarbons (PAHs) were employed as model analytes, respectively. The predominant parameters affecting extraction efficiency were investigated and optimized. Under the optimum experimental conditions, wide dynamic linear range (6.25–1600 ?g L?1 for diphenols and 1.56–100 ?g L?1 for PAHs) with good linearity (r2 ? 0.989) and low detection limits (0.34–16.67 ?g L?1 for diphenols and 0.26–0.52 ?g L?1 for PAHs) were achieved. The advantage of the developed method is that the Fe3O4@Au NPs could be reutilized for preconcentrating diverse target analytes in different SPE modes sequentially simply through treatment with desired thiol-containing ligands

22

Facile preparation of surface-exchangeable core@shell iron oxide@gold nanoparticles for magnetic solid-phase extraction: use of gold shell as the intermediate platform for versatile adsorbents with varying self-assembled monolayers.  

Science.gov (United States)

The core@shell Fe3O4@Au nanoparticles (NPs) functionalized with exchangeable self-assembled monolayers have been developed for mode switching magnetic solid-phase extraction (MSPE) using high performance liquid chromatography with ultraviolet detection. The adsorbents were synthesized by chemical coprecipitation to prepare magnetic cores followed by sonolysis to produce gold shells. Functionalization of Fe3O4@Au NPs surface was realized through self-assembly of commercially available low molecular weight thiol-containing ligands using gold shells as intermediate platform and the dynamic nature of Au-S chemistry allowed substituent of one thiol-containing ligand with another simply by thiol exchange process. The resultant adsorbents were characterized by transmission electronic microscopy, Fourier transform infrared spectroscopy, elemental analysis, contact angle measurement, and vibrating sample magnetometry. To evaluate the versatile performance of the developed MSPE adsorbents, they were applied for normal-phase SPE followed by reversed-phase SPE. A few kinds of diphenols and polycyclic aromatic hydrocarbons (PAHs) were employed as model analytes, respectively. The predominant parameters affecting extraction efficiency were investigated and optimized. Under the optimum experimental conditions, wide dynamic linear range (6.25-1600 ?g L(-1) for diphenols and 1.56-100 ?g L(-1) for PAHs) with good linearity (r(2)?0.989) and low detection limits (0.34-16.67 ?g L(-1) for diphenols and 0.26-0.52 ?g L(-1) for PAHs) were achieved. The advantage of the developed method is that the Fe3O4@Au NPs could be reutilized for preconcentrating diverse target analytes in different SPE modes sequentially simply through treatment with desired thiol-containing ligands. PMID:24456592

Li, Yaping; Qi, Li; Shen, Ying; Ma, Huimin

2014-02-01

23

Nanostructured carbons for solid phase extraction  

Science.gov (United States)

Nanostructured carbons have been obtained by the template method using zeolite NaY and silica gels (SG60, Fluka and ZK, POCh) as structure directing agents. Texture and porous structure of carbons were characterized by TEM, XRD and nitrogen adsorption. Surface chemistry was investigated by the potentiometric titration method. It has been shown that all carbons show developed and uniform porous structure with mean size in the micropore range (1.1 nm) for zeolite derived carbon and in the mesopore range (3.4 and 4.8 nm) for silica gel derived carbons. The BET surface area of silica gel derived carbons is in the range 1230-1280 m 2/g whereas zeolite derived carbon possesses very high BET surface area, 3000 m 2/g. Potentiometric titration showed that carbons obtained by the template method contain significant amount of acid surface groups (carboxylic, lactone/enol and phenolic) with the total amount 1.1-1.5 mmol/g. To study adsorption-desorption properties of nanostructured carbons towards phenol and chlorophenols the solid phase extraction method was used. High recoveries of chlorophenols were obtained (80-93%) at the breakthrough volumes 1700-3000 mL. The recoveries are much higher than that obtained with commercially available carbon ACC (Supelco).

Puziy, A. M.; Poddubnaya, O. I.; Gawdzik, B.; Sobiesiak, M.; Reinish, C. A.; Tsyba, M. M.; Segeda, T. P.; Danylenko, M. I.

2010-06-01

24

High-performance liquid chromatography analysis of phenolic acid, flavonoid, and phenol contents in various natural Yemeni honeys using multi-walled carbon nanotubes as a solid-phase extraction adsorbent.  

Science.gov (United States)

A simple method has been described for simultaneous determination of phenolic acid, flavonoid, and other phenol contents in various natural honey samples collected from various regions of Yemen. Multi-walled carbon nanotubes were used as a solid-phase adsorbent for extraction of the polyphenols from honey samples. The total contents of phenolic acids, flavonoids, and phenolic components of the 12 different samples were found in the range of 363-2658, 261-1646, and 224-1355 ?g/100 g of honey samples, respectively. The major phenolic acid, flavonoid, and phenolic compound in these samples were found to be 4-hydroxybenzoic acid (1410 ?g/100 g), chrysin (850 ?g/100 g), and cinnamic acid (1336 ?g/100 g), respectively. A total of 25 compounds (10 phenolic acids, 9 flavonoids, and 6 phenols) were analyzed, and a total of 24 were detected, while only 23 compounds were determined quantitatively in the honey samples. The developed method showed potential usefulness for the analysis of honey and was used for the determination of polyphenols in honey extracts. PMID:24871957

Badjah Hadj Ahmed, A Y; Obbed, Munir S; Wabaidur, Saikh M; AlOthman, Zeid A; Al-Shaalan, Nora H

2014-06-18

25

Facile preparation of surface-exchangeable core@shell iron oxide@gold nanoparticles for magnetic solid-phase extraction: Use of gold shell as the intermediate platform for versatile adsorbents with varying self-assembled monolayers  

Energy Technology Data Exchange (ETDEWEB)

Graphical abstract: -- Highlights: •The core@shell Fe{sub 3}O{sub 4}@Au nanoparticles functionalized with SAMs were successfully constructed. •The SAMs could be transformed from one kind to another via thiol exchange process. •The developed nanomaterials could be applied in mode switching MSPE. -- Abstract: The core@shell Fe{sub 3}O{sub 4}@Au nanoparticles (NPs) functionalized with exchangeable self-assembled monolayers have been developed for mode switching magnetic solid-phase extraction (MSPE) using high performance liquid chromatography with ultraviolet detection. The adsorbents were synthesized by chemical coprecipitation to prepare magnetic cores followed by sonolysis to produce gold shells. Functionalization of Fe{sub 3}O{sub 4}@Au NPs surface was realized through self-assembly of commercially available low molecular weight thiol-containing ligands using gold shells as intermediate platform and the dynamic nature of Au–S chemistry allowed substituent of one thiol-containing ligand with another simply by thiol exchange process. The resultant adsorbents were characterized by transmission electronic microscopy, Fourier transform infrared spectroscopy, elemental analysis, contact angle measurement, and vibrating sample magnetometry. To evaluate the versatile performance of the developed MSPE adsorbents, they were applied for normal-phase SPE followed by reversed-phase SPE. A few kinds of diphenols and polycyclic aromatic hydrocarbons (PAHs) were employed as model analytes, respectively. The predominant parameters affecting extraction efficiency were investigated and optimized. Under the optimum experimental conditions, wide dynamic linear range (6.25–1600 ?g L{sup ?1} for diphenols and 1.56–100 ?g L{sup ?1} for PAHs) with good linearity (r{sup 2} ? 0.989) and low detection limits (0.34–16.67 ?g L{sup ?1} for diphenols and 0.26–0.52 ?g L{sup ?1} for PAHs) were achieved. The advantage of the developed method is that the Fe{sub 3}O{sub 4}@Au NPs could be reutilized for preconcentrating diverse target analytes in different SPE modes sequentially simply through treatment with desired thiol-containing ligands.

Li, Yaping [Beijing National Laboratory of Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Graduate School, University of Chinese Academy of Sciences, Beijing 100049 (China); Qi, Li, E-mail: qili@iccas.ac.cn [Beijing National Laboratory of Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Shen, Ying [Beijing National Laboratory of Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Graduate School, University of Chinese Academy of Sciences, Beijing 100049 (China); Ma, Huimin [Beijing National Laboratory of Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

2014-02-06

26

Establishing the feasibility of coupled solid-phase extraction-solid-phase derivatization for acidic herbicides.  

Science.gov (United States)

The significance of this research is that it improves analytical methodology used for organic chemicals in aqueous solutions by establishing the feasibility of heterogeneous chemical derivatization at the liquid-solid interface (i.e., solid-phase reaction or solid-phase derivatization). A solid-phase derivatization method for determining chlorinated herbicide acids was developed. Solid-phase extraction was used to concentrate and retain analytes on sorbents for subsequent solid-phase derivatization. Background interferences were removed from the chromatograms by electronically subtracting the responses of blank, nonfortified analyses from spiked samples. Two extraction sorbents (octadecyl bonded silica and polystyrene-divinylbenzene) and two derivatizing reagents (BF3-MeOH and trimethylsilyldiazomethane) were investigated. Recovery of 13 chlorinated herbicide acids--including pentachlorophenol, dinoseb, and bentazon (having a derivatizable functional group, -OH or -NH, bonded directly to a phenyl group); dicamba, picloram, acifluorfen, 3,5-dichlorobenzoic acid, and dacthal (having a derivatizable functional group, -COOH, bonded directly to a phenyl group); and 2,4-D, 2,4,5-T, dichlorprop, 2,4,5-TP, and 2,4-DB (having a derivatizable functional group, -COOH, bonded directly to a sp3 carbon atom)--was tested. The analytical method developed was proven successful for determining acidic herbicides, except for the dacthal diacid metabolite, in aqueous samples. PMID:17214997

Yu, Lan Z; Wells, Martha J M

2007-03-01

27

Use of solid-phase adsorbents with the Microtox test for determining the toxicity of hydrophobic chemicals  

Energy Technology Data Exchange (ETDEWEB)

The determination of the toxicity of hydrophobic chemicals and to aquatic organisms can be a problem. Often no toxicity is found at concentrations near the solubility of the chemical in water. Solvents are used to increase the solubility of the chemical but the toxicity of the solvent may interfere with the test. Organic extracts of sediments and soil also suffer from the same solubility problems. The Solid-Phase Microtox Test protocol, which involves the incubation of Photobacterium phosphoreum with sediment particles, followed by removal of the particles by filtration, is used for the direct testing of sediment toxicity. The physical and chemical properties of the sediment, however, affect its apparent toxicity to Microtox, giving variable results between polluted and unpolluted sites. Adsorbents, designed for solid-phase extraction, were used as surrogate sediment particles. Toxicants were adsorbed to these materials and were tested for toxicity using the Solid Phase Microtox Test. The advantage of using the absorbent is that they are have a defined surface chemistry, particle size and pore size. Adsorbents containing a variety of functional groups are widely available and can be used for concentrating toxicants from solution by ion exchange, normal phase or reversed phase chromatographic processes. The toxicity of a range of adsorbents to Microtox was determined using the solid-phase protocols. The most toxic absorbent were Florisil and NH{sub 2}(amino) with EC,, values of 2.1 and 5.7 g/L, respectively. Most absorbent had EC{sub 50} values between 50 and 100 g/L and could be used in small amounts for Microtox Tests. Diol and CN(cyanopropyl) absorbent showed no toxicity at concentrations of 100 g/L, the equivalent of one solid-phase cartridge (300 mg) in 3 mL Microtox diluent.

Vaughan, G.T. [CSIRO Division of Coal and Energy Technology, Sydney, New South Wales (Australia). Centre for Advanced Analytical Chemistry

1995-12-31

28

Modified resins for solid-phase extraction  

Science.gov (United States)

A process of treating aqueous solutions to remove organic solute contaminants by contacting an aqueous solution containing polar organic solute contaminants with a functionalized polystyrene-divinyl benzene adsorbent resin, with the functionalization of said resin being accomplished by organic hydrophilic groups such as hydroxymethyl, acetyl and cyanomethyl.

Fritz, James S. (Ames, IA); Sun, Jeffrey J. (Ames, IA)

1993-07-27

29

Solid-phase extraction in segmented flow.  

Science.gov (United States)

Two-phase flow systems are increasingly popular for miniaturized, high-throughput performance of analytical or chemical reactions. In this contribution, we extend a previously described method that allows to increase the range of applications of heterogeneous reactions in two-phase flow, i.e., reactions that rely on isolation and purification of the compound of interest for downstream analysis. Our concept is based on liquid plugs, which serve as miniaturized compartments for the analytical reactions. Purification of the target compound is achieved by extracting the analyte from the aqueous compartments using magnetic beads as solid carriers. In the present paper, we elucidate the influence of parameters such as the polarity of the liquid/liquid and solid/liquid interfaces, the magnetic forces and the fluidic conditions onto the extraction performance. The conditions for reliable extraction and purification of the target compounds are determined. Furthermore, we investigate how to facilitate breaking of the plugs through reduction of the surface tension of the solid/liquid interface. When a lower surface tension is employed, a smaller number of beads is required for the extraction process, which implies a higher sensitivity of the device. In addition, we generate channels with different surface chemistries, which are able to manipulate the flow of the two immiscible liquids. We describe a very simple way to generate such devices and show that we can achieve a transition from segmented flow of plugs to a side-by side flow of the two immiscible liquids, a key requirement for the purification of the compounds. PMID:25300748

Rendl, Martin; Brandstetter, Thomas; Rühe, Jürgen

2014-11-01

30

Hierarchically imprinted mesoporous silica polymer: an efficient solid-phase extractant for bisphenol A.  

Science.gov (United States)

Improving the site accessibility of molecularly imprinted polymer (MIP) is one of the biggest challenges for application of MIP in solid-phase extraction (SPE). Hierarchically imprinted mesoporous silica polymer was prepared with semicovalently bond imprinting methods based on MCM-41 and SBA-15 mesostructures, aiming to improve the site accessibility of MIP and increase the efficiency of molecularly imprinted-SPE. Characterization and performance tests of the obtained products revealed that molecularly imprinted SBA-15 (MIP-SBA-15) not only retained the mesoporous structure of SBA-15, but also displayed excellent selectivity of MIP to the target molecule. As the MIP-SBA-15 were adopted as the adsorbents of solid-phase extraction for detecting bisphenol A in spiked water samples, the recoveries of spiked samples more than 87%, which reveals that the molecularly imprinted SBA-15 were efficient SPE adsorbents for bisphenol A. PMID:24468367

Cheng, Wenjing; Ma, Haotian; Zhang, Li; Wang, Yan

2014-03-01

31

Solid phase micro-extraction in environmental atmosphere  

International Nuclear Information System (INIS)

Solid phase micro-extraction (SPME) is an advanced technique of sample pretreatment in environmental atmosphere analysis, i.e., a sampling method of extracting volatile organic compounds from environmental gas. According to the primary survey on the theory and application of SPME, a suitable extraction tip, i.e., a coated fused silica fiber, is selected to construct a SPME apparatus. This SPME apparatus is used to extract volatile organic compounds from environmental atmosphere and a qualitative detection is conducted in gas chromatography-mass spectrometer system. Good experimental results are obtained

32

Extraction of Pb2+ using Silica from Rice Husks Ash (RHA – Chitosan as Solid Phase  

Directory of Open Access Journals (Sweden)

Full Text Available The existence of lead (Pb compounds in waters can be caused of waste pollution from industrial activities such as dye and battery industries. Lead has toxic characteristic and is able to causing deseases. The levels of Cr(VI can be decreased by methods such as electroplating, oxidation, reduction, and membrane separation. But this methods require high cost and produce a lot of waste. Furthermore, those methods cannot determine the small concentration of Pb2+. Therefore, solid phase extraction is used because it’s a simple method and can be used to preconcentrate Pb2+ ion. The aim of this study is to create solid phase from nature material as an alternative method to determine Pb2+ in water samples. The solid phase is silica from rice husks ash (RHA that was modified using chitosan. To achieve that aim, the optimization of silica : chitosan composition was done. The influence of Pb2+ concentration and citric acid concentration was studied to obtain optimum recovery of Pb2+. Interaction between Pb2+ ion and solid phase silica – chitosan could be estimated based on the result. The result showed the optimum composition of silica : chitosan is 65% silica : 35% chitosan with Cation Exchange Capacity (CEC 0.00455 mek/g. Mass Adsorbed Pb2+for 1 g silica : chitosan 65% is 9.715 mg/g. Optimum recovery of Pb2+ on solid phase extraction is reached at concentration of Pb2+ 10 ppm and citric acid concentration 0.05 M (88.25 % and 81.18 %. This result showed that solid phase extraction using silica – chitosan can be used as an alternative method to determine Pb2+ in water.

Hanandayu Widwiastuti

2013-03-01

33

Preparation of bioconjugates by solid-phase conjugation to ion exchange matrix-adsorbed carrier proteins  

DEFF Research Database (Denmark)

A solid-phase conjugation method utilizing carrier protein bound to an ion exchange matrix was developed. Ovalbumin was adsorbed to an anion exchange matrix using a batch procedure, and the immobilized protein was then derivatized with iodoacetic acid N-hydroxysuccinimid ester. The activated protein was conjugated with glutathione, the conjugation ratio determined by acid hydrolysis, and amino acid analysis performed with quantification of carboxymethyl cysteine. Elution of conjugates from the resin by a salt gradient revealed considerable heterogeneity in the degree of derivatization, and immunization experiments with the eluted conjugates showed that the more substituted conjugates gave rise to the highest titers of glutathione antibodies. Direct immunization with the conjugates adsorbed to the ion exchange matrix was possible and gave rise to high titers of glutathione antibodies. Conjugates of ovalbumin and various peptides were prepared in a similar manner and used for production of peptide antisera by direct immunization with the conjugates bound to the ion exchanger. Advantages of the method are its solid-phase nature, allowing fast and efficient reactions and intermediate washings, and the ability to release conjugates from the solid phase under mild conditions.

Barkholt, Vibeke

2003-01-01

34

Multiwalled carbon nanotubes as a solid-phase extraction adsorbent for the determination of three barbiturates in pork by ion trap gas chromatography-tandem mass spectrometry (GC/MS/MS) following microwave assisted derivatization  

Energy Technology Data Exchange (ETDEWEB)

A new method was developed for the rapid screening and confirmation analysis of barbital, amobarbital and phenobarbital residues in pork by gas chromatography-tandem mass spectrometry (GC/MS/MS) with ion trap MSD. The residual barbiturates in pork were extracted by ultrasonic extraction, cleaned up on a multiwalled carbon nanotubes (MWCNTs) packed solid phase extraction (SPE) cartridge and applied acetone-ethyl acetate (3:7, v/v) mixture as eluting solvent and derivatized with CH{sub 3}I under microwave irradiation. The methylated barbiturates were separated on a TR-5MS capillary column and detected with an ion trap mass detector. Electron impact ion source (EI) operating MS/MS mode was adopted for identification and external standard method was employed for quantification. One precursor ion m/z 169 was selected for analysis of barbital and amobarbital and m/z 232 was selected for phenobarbital. The product ions were obtained under 1.0 V excitation voltage. Good linearities (linear coefficient R > 0.99) were obtained at the range of 0.5-50 {mu}g kg{sup -1}. Limit of detection (LOD) of barbital was 0.2 {mu}g kg{sup -1} and that of amobarbital and phenobarbital were both 0.1 {mu}g kg{sup -1} (S/N {>=} 3). Limit of quatification (LOQ) was 0.5 {mu}g kg{sup -1} for three barbiturates (S/N {>=} 10). Satisfying recoveries ranging from 75% to 96% of the three barbiturates spiked in pork were obtained, with relative standard deviations (R.S.D.) in the range of 2.1-7.8%.

Zhao Haixiang [College of Science, China Agricultural University, Beijing 100094 (China); Inspection Technology and Equipment Institute, Chinese Academy of Inspection and Quarantine, Beijing 100025 (China); Department of Basic Agricultural Science, Hebei North College, Zhangjiakou Hebei 075131 (China); Wang Liping [College of Science, China Agricultural University, Beijing 100094 (China); Qiu Yueming [Inspection Technology and Equipment Institute, Chinese Academy of Inspection and Quarantine, Beijing 100025 (China); Zhou Zhiqiang [College of Science, China Agricultural University, Beijing 100094 (China)]. E-mail: zqzhou@cau.edu.cn; Zhong Weike [Inspection Technology and Equipment Institute, Chinese Academy of Inspection and Quarantine, Beijing 100025 (China); Li Xiang [Inspection Technology and Equipment Institute, Chinese Academy of Inspection and Quarantine, Beijing 100025 (China)

2007-03-14

35

Multi-walled carbon nanotubes as solid-phase extraction adsorbent for the ultra-fast determination of chloramphenicol in egg, honey, and milk by fused-core C18-based high-performance liquid chromatography-tandem mass spectrometry.  

Science.gov (United States)

In the present work, a high-performance liquid chromatography-tandem mass spectrometry method has been developed for the residue analysis of chloramphenicol (CAP) in several food matrices. Following the addition of D(5)-CAP as internal standard, egg, honey, and milk were extracted and cleaned by means of solid-phase extraction, utilizing multi-walled carbon nanotubes as sorbent. The extracts were separated on a Halo fused-core C18 column (50 mm × 2.1 mm, 2.7 ?m) and quantified by a 4000 Q-trap mass spectrometer equipped with a TurboIonSpray™ interface using electrospray ionization and multiple-reaction monitoring mode. The method validation was performed according to the criteria of Commission Decision 2002/657/EC. The decision limit (CC?) and detection capability (CC?) of CAP in milk were calculated for m/z 320.8 > 151.9. Due to the existence of slight signal suppression, quantification was performed by matrix-matched calibration curves, ranging from 0.1 to 100 ng mL(-1), with regression coefficients of 0.9993, 0.9998, and 0.9997 for egg, honey, and milk, respectively. Mean recoveries of the CAP ranged from 95.8% to 102.3%, with the corresponding intra- and inter-day variation (relative standard deviation) less than 7.13% and 8.89%, respectively. The limit of detection and limit of quantification of the method were also reported. This method successfully applied to several food matrixes (egg, honey, and milk) and can serve as a monitoring tool to avoid unacceptable levels of residues of CAP entering the food chain. PMID:20737139

Lu, Yanbin; Shen, Qing; Dai, Zhiyuan; Zhang, Hong

2010-10-01

36

Advances in solid-phase extraction disks for environmental chemistry  

Science.gov (United States)

The development of solid-phase extraction (SPE) for environmental chemistry has progressed significantly over the last decade to include a number of new sorbents and new approaches to SPE. One SPE approach in particular, the SPE disk, has greatly reduced or eliminated the use of chlorinated solvents for the analysis of trace organic compounds. This article discusses the use and applicability of various SPE disks, including micro-sized disks, prior to gas chromatography-mass spectrometry for the analysis of trace organic compounds in water. Copyright (C) 2000 Elsevier Science B.V.

Thurman, E.M.; Snavely, K.

2000-01-01

37

Evaluation of solid-phase extraction procedures in peptide analysis.  

Science.gov (United States)

Solid-phase extraction (SPE) procedures for peptide isolation and fractionation, based on non-polar and ionic interactions, were evaluated using small synthetic peptides and casein enzymatic hydrolysates. SPE based on hydrophobic phases is a useful, efficient and rapid procedure for peptide extraction and concentration. It allows a successful peptide fractionation using eluents that contain an increasing content of acetonitrile in the presence of trifluoroacetic acid. Differences regarding selectivity are observed between sorbents. Non-polar interaction with C18 sorbents is adequate for the isolation of very polar and hydrophobic peptides. CN sorbents are only adequate for very hydrophobic peptides. PH, CH, C8 and C2 sorbents are useful for isolating and fractionating hydrophobic and very non-polar peptides, but generally not for very polar peptides. Ionic solid-phase extraction using Accell Plus cartridges of QMA (quaternary methylammonium) and CM (carboxymethyl) are very useful for the fractionation of peptide mixtures into basic, acidic and neutral pools of peptides. It can be concluded that SPE using these procedures is a useful tool for the isolation and fractionation of peptides from biological and food samples. PMID:7647925

Herraiz, T; Casal, V

1995-08-01

38

Magnetic nanoparticle-based solid-phase extraction of vitamin B12 from pharmaceutical formulations.  

Science.gov (United States)

In the present study, a novel quantitative method, namely magnetic nanoparticle-based solid-phase extraction (MSPE), was applied to extract vitamin B(12) from pharmaceutical formulations. The technique involves the use of Fe(3)O(4) nanoparticles modified by sodium dodecyl sulfate (SDS) as an efficient adsorbent for solid-phase extraction of vitamin B(12). Collection of magnetic nanoparticles (MNPs) from aqueous solution was simply achieved by applying external magnetic field. The analyte was desorbed from MNPs using alkali 1-propanol. The extracted analyte was analyzed by using flow injection inductively coupled plasma-optical emission spectrometry. Factors affecting the extraction efficiency were investigated and optimized. Under the optimum conditions, enhancement factor of 184, linear dynamic range of 2.5-500 ?g L(-1) with correlation of determination (R(2) > 0.999), and limit of detection of 1.0 ?g L(-1) were obtained for vitamin B(12). The percent relative standard deviation based on five-replicate determination was less than 6.2%. The method was successfully applied for extraction and determination of vitamin B(12) in different types of pharmaceutical samples such as multivitamin tablet, effervescent tablet, and injection sample. The results showed that the proposed method based on SDS-Fe(3)O(4) MSPE was a simple, accurate, and highly efficient approach for analysis of vitamin B(12). PMID:22187326

Yamini, Yadollah; Tahmasebi, Elham; Ranjbar, Leila

2012-06-01

39

Solid phase extraction of nitrate and nitrite anions using naturally and available sorbent  

International Nuclear Information System (INIS)

Radioactive waste contains nitrate and nitrite as well as radioactive fission products. Nitrate and nitrite anions are two of the major components of nuclear waste streams and contribute to environmental release hazards. The removal of nitrate and nitrite is a necessary step for the further treatment low-level radioactive wastes. The focus of the research is to evaluate the adsorption potential of solid phase derived from rice straw for nitrate and nitrite anions in single- and binary-component systems due to the fact that the rice straw is a very abundant and by-product material. The removal was accomplished under the optimize conditions of temperature, concentration, pH, contact time and quantity of adsorbent as these parameters are some of the main factors influencing the uptake of two solutes at the solid-solution interface. Batch-mode kinetic and equilibrium studies have been carried out. The experimental data was analyzed using equilibrium isotherm and kinetic models. The thermodynamic parameters (?Gdeg, ?Hdeg, and ?Sdeg) were also determined using the equilibrium constant value obtained at different temperatures. Results show that this adsorbent is effective and much better or even superior than many sorbents for removal of nitrate and nitrite. The prepared sorbent as solid-phase extractant was successfully applied for the extraction of nitrate from actual water samples. (author)

40

Molecular imprinting solid phase extraction for selective detection of methidathion in olive oil.  

Science.gov (United States)

A specific adsorbent for extraction of methidathion from olive oil was developed. The design of the molecularly imprinted polymer (MIP) was based on the results of the computational screening of the library of polymerisable functional monomers. MIP was prepared by thermal polymerisation using N,N'-methylene bisacrylamide (MBAA) as a functional monomer and ethylene glycol dimethacrylate (EGDMA) as a cross-linker. The polymers based on the itaconic acid (IA), methacrylic acid (MAA) and 2-(trifluoromethyl)acryl acid (TFMAA) functional monomers and one control polymer which was made without functional monomers with cross-linker EGDMA were also synthesised and tested. The performance of each polymer was compared using corresponding imprinting factor. As it was predicted by molecular modelling the best results were obtained for the MIP prepared with MBAA. The obtained MIP was optimised in solid-phase extraction coupled with high performance liquid chromatography (MISPE-HPLC-UV) and tested for the rapid screening of methidathion in olive oil. The proposed method allowed the efficient extraction of methidathion for concentrations ranging from 0.1 to 9 mg L(-1) (r(2)=0.996). The limits of detection (LOD) and quantification (LOQ) in olive oil were 0.02 mg L(-1) and 0.1 mg L(-1), respectively. MIPs extraction was much more effective than traditional C18 reverse-phase solid phase extraction. PMID:22704478

Bakas, Idriss; Oujji, Najwa Ben; Moczko, Ewa; Istamboulie, Georges; Piletsky, Sergey; Piletska, Elena; Ait-Ichou, Ihya; Ait-Addi, Elhabib; Noguer, Thierry; Rouillon, Régis

2012-07-13

 
 
 
 
41

[Corrected Title: Solid-Phase Extraction of Polar Compounds from Water] Automated Electrostatics Environmental Chamber  

Science.gov (United States)

A solid-phase extraction (SPE) process has been developed for removing alcohols, carboxylic acids, aldehydes, ketones, amines, and other polar organic compounds from water. This process can be either a subprocess of a water-reclamation process or a means of extracting organic compounds from water samples for gas-chromatographic analysis. This SPE process is an attractive alternative to an Environmental Protection Administration liquid-liquid extraction process that generates some pollution and does not work in a microgravitational environment. In this SPE process, one forces a water sample through a resin bed by use of positive pressure on the upstream side and/or suction on the downstream side, thereby causing organic compounds from the water to be adsorbed onto the resin. If gas-chromatographic analysis is to be done, the resin is dried by use of a suitable gas, then the adsorbed compounds are extracted from the resin by use of a solvent. Unlike the liquid-liquid process, the SPE process works in both microgravity and Earth gravity. In comparison with the liquid-liquid process, the SPE process is more efficient, extracts a wider range of organic compounds, generates less pollution, and costs less.

Sauer, Richard; Rutz, Jeffrey; Schultz, John

2005-01-01

42

New methods and materials for solid phase extraction and high performance liquid chromatography  

Energy Technology Data Exchange (ETDEWEB)

This paper describes methods for solid phase extraction and high performance liquid chromatography (HPLC). The following are described: Effects of Resin Sulfonation on the Retention of Polar Organic Compounds in Solid Phase Extraction; Ion-Chromatographic Separation of Alkali Metals In Non-Aqueous Solvents; Cation-Exchange Chromatography in Non-Aqueous Solvents; and Silicalite As a Stationary Phase For HPLC.

Dumont, P.J.

1996-04-23

43

MOLECULAR IMPRINTED SOLID PHASE EXTRACTION FOR DETERMINATION OF ATRAZINE IN ENVIRONMENTAL SAMPLES  

Directory of Open Access Journals (Sweden)

Full Text Available Solid phase extraction is one of the major applications of molecularly imprinted polymers fields for clean-up of environmental and biological samples namely molecularly imprinted solid-phase extraction. In this study, solid phase extraction using the imprinted polymer has been optimized with the experimental design approach for a triazine herbicide, named atrazine with regard to the critical factors which influence the molecular imprinted solid phase extraction efficiency such as sample pH, concentration, flow-rate, volume, elution solvent, washing solvent and sorbent mass. Optimization methods that involve changing one factor at a time can be laborious. A novel approach for the optimization of imprinted solid-phase extraction using chemometrics is described. The factors were evaluated statistically and also validated with spiked water samples and showed a good reproducibility over six consecutive days as well as six within-day experiments. Also, in order to the evaluate efficiency of the optimized molecularly imprinted solid-phase extraction protocols, enrichment capacity, reusability and cross-reactivity of cartridges have been also evaluated. Finally, selective molecularly imprinted solid-phase extraction of atrazine was successfully demonstrated with a recovery above 90% for spiked drinking water samples. It was concluded that the chemometrics is frequently employed for analytical method optimization and based on the obtained results, it is believed that the central composite design could prove beneficial for aiding the molecularly imprinted polymer and molecularly imprinted solid-phase extraction development.

A. R. Koohpaei ? S. J. Shahtaheri ? M. R. Ganjali ? A. Rahimi Forushani

2008-10-01

44

MOLECULARLY IMPRINTED SOLID PHASE EXTRACTION FOR TRACE ANALYSIS OF DIAZINON IN DRINKING WATER  

Directory of Open Access Journals (Sweden)

Full Text Available Amongst organophosphate pesticides, the one most widely used and common environmental contaminant is diazinon; thus methods for its trace analysis in environmental samples must be developed. Use of diazinon imprinted polymers such as sorbents in solid phase extraction, is a prominent and novel application area of molecular imprinted polymers. For diazinon extraction, high performance liquid chromatography analysis was demonstrated in this study. During optimization of the molecular imprinted solid phase extraction procedure for efficient solid phase extraction of diazinon, Plackett-Burman design was conducted. Eight experimental factors with critical influence on molecular imprinted solid phase extraction performance were selected, and 12 different experimental runs based on Plackett-Burman design were carried out. The applicability of diazinon imprinted polymers as the sorbent in solid phase extraction, presented obtained good recoveries of diazinon from LC-grade water. An increase in pH caused an increase in the recovery on molecular imprinted solid phase extraction. From these results, the optimal molecular imprinted solid phase extraction procedure was as follows: solid phase extraction packing with 100 mg diazinon imprinted polymers; conditioning with 5 mL of methanol and 6 mL of LC-grade water; sample loading containing diazinon (pH=10; washing with 1 mL of LC-grade water, 1 mL LC- grade water containing 30% acetonitrile and 0.5 mL of acetonitrile, respectively; eluting with 1 mL of methanol containing 2% acetic acid. The percentage recoveries obtained by the optimized molecular imprinted solid phase extraction were more than 90% with drinking water spiked at different trace levels of diazinon. Generally speaking, the molecular imprinted solid phase extraction procedure and subsequent high performance liquid chromatography analysis can be a relatively fast and proper approach for qualitative and quantitative analysis of diazinon in drinking water.

M. Rahiminejad ? S. J. Shahtaheri ? M. R. Ganjali ? A. Rahimi Forushani ? F. Golbabaei

2009-04-01

45

Novel materials and methods for solid-phase extraction and liquid chromatography  

Energy Technology Data Exchange (ETDEWEB)

This report contains a general introduction which discusses solid-phase extraction and solid-phase micro-extraction as sample preparation techniques for high-performance liquid chromatography, which is also evaluated in the study. This report also contains the Conclusions section. Four sections have been removed and processed separately: silicalite as a sorbent for solid-phase extraction; a new, high-capacity carboxylic acid functionalized resin for solid-phase extraction; semi-micro solid-phase extraction of organic compounds from aqueous and biological samples; and the high-performance liquid chromatographic determination of drugs and metabolites in human serum and urine using direct injection and a unique molecular sieve.

Ambrose, D.

1997-06-24

46

Improved resins and novel materials and methods for solid phase extraction and high performance liquid chromatography  

Energy Technology Data Exchange (ETDEWEB)

Solid-phase extraction (SPE) has grown to be one of the most widely used methods for isolation and preconcentration of a vast range of compounds from aqueous solutions. By modifying polymeric SPE resins with chelating functional groups, the selective uptake of metals was accomplished. The resin, along with adsorbed metals, was vaporized in the ICP and detection of the metals was then possible using either mass or emission spectroscopy. Drug analyses in biological fluids have received heightened attention as drug testing is on the increase both in sports and in the work environment. By using a direct-injection technique, biological fluids can be injected directly into the liquid chromatographic system with no pretreatment. A new surfactant, a sulfonated form of Brij-30 (Brij-S) is shown to prevent the uptake of serum proteins on commercial HPLC columns by forming a thin coating on the silica C18 surface. Excellent separations of eight or more drugs with a wide range of retention times were obtained. The separations had sharper peaks and lower retention times than similar separations performed with the surfactant sodium dodecylsulfate (SDS). Quantitative recovery of a number of drugs with limits of detection near 1 ppm with a 5 {micro}l injection volume were obtained. Finally, a method for solid-phase extraction in a syringe is introduced. The system greatly reduced the volume of solvent required to elute adsorbed analytes from the SPE bed while providing a semi-automated setup. SPE in a syringe consists of a very small bed of resin-loaded membrane packed into a GC or HPLC syringe. After extraction, elution was performed with just a few {micro}l of solvent. This small elution volume allowed injection of the eluent directly from the syringe into the chromatographic system, eliminating the handling problems associated with such small volumes.

Freeze, R.

1997-10-08

47

COMPARATIVE YIELDS OF MUTAGENS FROM CIGARETTE SMOKERS' URINE OBTAINED BY USING SOLID-PHASE EXTRACTION TECHNIQUES  

Science.gov (United States)

Urine from cigarette smokers was prepared for mutagenicity testing by extracting mutagens with solid phase extraction columns. ommercially available prepacked bonded silicas (cotadecyl, cyclohexyl, cyanopropyl) were compared for their efficiency and specificity in concentration o...

48

Selective solid-phase extraction of uranium by salicylideneimine-functionalized hydrothermal carbon  

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer Hydrothermal carbon material as solid-phase extractant matrix. Black-Right-Pointing-Pointer An excellent hexavalent cation ligand, salicylideneimine, is grafted on the matrix. Black-Right-Pointing-Pointer Adsorbent shows high affinity and selectivity to U(VI) in simulated nuclear effluent. Black-Right-Pointing-Pointer Process is fast, endothermic, spontaneous, and pseudo-second-order chemisorption. - Abstract: A new salicylideneimine-functionalized hydrothermal-carbon-based solid-phase extractant was developed for the purpose of separating uranium selectively for sustainability of uranium resources. The resulting adsorption material was obtained via hydrothermal carbonization, calcination at mild temperature (573.15 K), amination, and grafting with salicylaldehyde in sequence. Both Fourier transform infrared spectra and elemental analysis proved the successful grafting of salicylideneimine onto hydrothermal carbon matrix. Adsorption behaviors of the extractant on uranium(VI) were investigated by varying pH values of solution, adsorbent amounts, contact times, initial metal concentrations, temperatures, and ionic strengths. An optimum adsorption capacity of 1.10 mmol g{sup -1} (261 mg g{sup -1}) for uranium(VI) was obtained at pH 4.3. The present adsorption process obeyed pseudo-second-order model and Langmuir isotherm. Thermodynamic parameters ({Delta}H = +8.81 kJ mol{sup -1}, {Delta}S = +110 J K{sup -1} mol{sup -1}, {Delta}G = -23.0 kJ mol{sup -1}) indicated the adsorption process was endothermic and spontaneous. Results from batch adsorption test in simulated nuclear industrial effluent, containing Cs{sup +}, Sr{sup 2+}, Ba{sup 2+}, Mn{sup 2+}, Co{sup 2+}, Ni{sup 2+}, Zn{sup 2+}, La{sup 3+}, Ce{sup 3+}, Nd{sup 3+}, Sm{sup 3+}, and Gd{sup 3+}, showed the adsorbent could separate uranium(VI) from those competitive ions with high selectivity. The adsorbent might be promising for use in certain key steps in any future sustainable nuclear fuel cycle.

Wang, Hang; Ma, Lijian; Cao, Kecheng; Geng, Junxia; Liu, Jun; Song, Qiang; Yang, Xiaodan [College of Chemistry, Sichuan University, Key Laboratory of Radiation Physics and Technology (Sichuan University), Ministry of Education, Chengdu 610064 (China); Li, Shoujian, E-mail: sjli000616@scu.edu.cn [College of Chemistry, Sichuan University, Key Laboratory of Radiation Physics and Technology (Sichuan University), Ministry of Education, Chengdu 610064 (China)

2012-08-30

49

Optimization of cloud point extraction and solid phase extraction methods for speciation of arsenic in natural water using multivariate technique  

International Nuclear Information System (INIS)

The simple and rapid pre-concentration techniques viz. cloud point extraction (CPE) and solid phase extraction (SPE) were applied for the determination of As3+ and total inorganic arsenic (iAs) in surface and ground water samples. The As3+ was formed complex with ammonium pyrrolidinedithiocarbamate (APDC) and extracted by surfactant-rich phases in the non-ionic surfactant Triton X-114, after centrifugation the surfactant-rich phase was diluted with 0.1 mol L-1 HNO3 in methanol. While total iAs in water samples was adsorbed on titanium dioxide (TiO2); after centrifugation, the solid phase was prepared to be slurry for determination. The extracted As species were determined by electrothermal atomic absorption spectrometry. The multivariate strategy was applied to estimate the optimum values of experimental factors for the recovery of As3+ and total iAs by CPE and SPE. The standard addition method was used to validate the optimized methods. The obtained result showed sufficient recoveries for As3+ and iAs (>98.0%). The concentration factor in both cases was found to be 40.

50

On-line solid phase selective separation and preconcentration of Cd(II) by solid-phase extraction using carbon active modified with methyl thymol blue  

Energy Technology Data Exchange (ETDEWEB)

An on-line flow system was used to develop a selective and efficient on-line sorbent extraction preconcentration system for cadmium. The method is based on adsorption of cadmium ions onto the activated carbon modified with methyl thymol blue. Then the adsorbed ions were washed using 0.5 M HNO{sub 3} and the eluent was used to determine the Cd(II) ions using flame atomic absorption spectrometry. The results obtained show that the modified activated carbon has the greatest adsorption capacity of 80 {mu}g of Cd(II) per 1.0 g of the solid phase. The optimal pH value for the quantitative preconcentration was 9.0 and full desorption is achieved by using 0.5 M HNO{sub 3} solution. It is established that the solid phase can be used repeatedly without a considerable adsorption capacity loss. The detection limit was less than 1 ng mL{sup -1} Cd(II), with an enrichment factor of 1000. The calibration graph was linear in the range of 1-2000 ng mL{sup -1} Cd(II). The developed method has been applied to the determination of trace cadmium (II) in water samples and in the following reference materials: sewage sludge (CRM144R), and sea water (CASS.4) with satisfactory results. The accuracy was assessed through recovery experiments.

Ensafi, Ali A. [College of Chemistry, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)], E-mail: Ensafi@cc.iut.ac.ir; Ghaderi, Ali R. [College of Chemistry, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

2007-09-05

51

On-line solid phase selective separation and preconcentration of Cd(II) by solid-phase extraction using carbon active modified with methyl thymol blue  

International Nuclear Information System (INIS)

An on-line flow system was used to develop a selective and efficient on-line sorbent extraction preconcentration system for cadmium. The method is based on adsorption of cadmium ions onto the activated carbon modified with methyl thymol blue. Then the adsorbed ions were washed using 0.5 M HNO3 and the eluent was used to determine the Cd(II) ions using flame atomic absorption spectrometry. The results obtained show that the modified activated carbon has the greatest adsorption capacity of 80 ?g of Cd(II) per 1.0 g of the solid phase. The optimal pH value for the quantitative preconcentration was 9.0 and full desorption is achieved by using 0.5 M HNO3 solution. It is established that the solid phase can be used repeatedly without a considerable adsorption capacity loss. The detection limit was less than 1 ng mL-1 Cd(II), with an enrichment factor of 1000. The calibration graph was linear in the range of 1-2000 ng mL-1 Cd(II). The developed method has been applied to the determination of trace cadmium (II) in water samples and in the following reference materials: sewage sludge (CRM144R), and sea water (CASS.4) with satisfactory results. The accuracy was assessed through recovery experiments

52

Enhanced spectrofluorimetric determination of aflatoxin M1 in liquid milk after magnetic solid phase extraction  

Science.gov (United States)

A simple and sensitive method using magnetic solid phase extraction (MSPE) followed by spectrofluorimetric detection has been developed for separation and determination of aflatoxin M1 (AFM1) in liquid milk. The method is based on the extraction of AFM1 on the modified magnetic nanoparticles (MMNPs) and subsequent derivatization of extracted AFM1 to AFM1 hemi-acetal derivative (AFM2a) by reaction with trifluoroacetic acid (TFA) for spectrofluorimetric detection. Magnetic nanoparticles (MNPs) coated by 3-(trimethoxysilyl)-1-propantiol (TMSPT) and modified with 2-amino-5-mercapto-1,3,4-thiadiazole (AMT) were used as adsorbent in MSPE procedure. Influential parameters affecting the extraction efficiency were investigated and optimized. Under the optimum conditions the calibration curve for AFM1 determination showed good linearity in the range 0.030-10.0 ?g L-1 (R2 = 0.9991). The repeatability and reproducibility (RSD%) for 0.050 ?g L-1 of AFM1 were 4.5% and 5.3%, respectively and limit of detection limit (S/N = 3) was estimated to be 0.010 ?g L-1. The developed method was successfully applied for extraction of AFM1 from spiked liquid milk and natural contaminated liquid milk. The good spiked recoveries ranging from 91.6% to 96.1% were obtained. The results demonstrated that the developed method is simple, inexpensive, accurate and remarkably free from interference effects.

Hashemi, Mahdi; Taherimaslak, Zohreh; Rashidi, Somayeh

2014-07-01

53

Mixed micelle cloud point-magnetic dispersive ?-solid phase extraction of doxazosin and alfuzosin.  

Science.gov (United States)

Mixed micelle cloud point extraction (MM-CPE) combined with magnetic dispersive ?-solid phase extraction (MD-?-SPE) has been developed as a new approach for the extraction of doxazosin (DOX) and alfuzosin (ALF) prior to fluorescence analysis. The mixed micelle anionic surfactant sodium dodecyl sulfate and non-ionic polyoxyethylene(7.5)nonylphenylether was used as the extraction solvent in MM-CPE, and diatomite bonding Fe?O? magnetic nanoparticles were used as the adsorbent in MD-?-SPE. The method was based on MM-CPE of DOX and ALF in the surfactant-rich phase. Magnetic materials were used to retrieve the surfactant-rich phase, which easily separated from the aqueous phase under magnetic field. At optimum conditions, a linear relationship between DOX and ALF was obtained in the range of 5-300 ng mL(-1), and the limits of detection were 0.21 and 0.16 ng mL(-1), respectively. The proposed method was successfully applied for the determination of the drugs in pharmaceutical preparations, urine samples, and plasma samples. PMID:24995413

Gao, Nannan; Wu, Hao; Chang, Yafen; Guo, Xiaozhen; Zhang, Lizhen; Du, Liming; Fu, Yunlong

2015-01-01

54

Microwave distillation-solid phase adsorbent trapping device for the determination of off-flavors, geosmin and methylisoborneol, in catfish tissue below their rejection levels  

Energy Technology Data Exchange (ETDEWEB)

Described is a rapid microwave-mediated steam distillation device for determining two predominant off-flavor compounds, geosmin and methylisoborneol, in catfish tissue. A microwave on-time of 10 min is needed to efficiently remove these off-flavor compounds from the sample matrix and trap them on a solid phase adsorbent. A minimal amount of organic solvent is used to elute the trapped compounds. The extract is then analyzed by gas chromatography with ion trap detection in the selective ion storage mode. Detection limits in the sub-parts-per-billion range are obtained with this method. 11 refs., 5 figs., 1 tab.

Conte, E.D.; Shen, C.Y.; Miller, D.W. [National Center for Toxicological Research, Jefferson, AK (United States); Perschbacher, P.W. [Univ. of Arkansas, Pine Bluff, AK (United States)

1996-08-01

55

ZnO nanorod array solid phase micro-extraction fiber coating: fabrication and extraction capability  

International Nuclear Information System (INIS)

In this paper, a ZnO nanorod array has been introduced as a coating to the headspace solid phase micro-extraction (HSSPME) field. The coating shows good extraction capability for volatile organic compounds (VOCs) by use of BTEX as a standard and can be considered suitable for sampling trace and small molecular VOC targets. In comparison with the randomly oriented ZnO nanorod HSSPME coating, ZnO nanorod array HSSPME fiber coating shows better extraction capability, which is attributed to the nanorod array structure of the coating. Also, this novel nanorod array coating shows good extraction selectivity to 1-propanethiol.

56

Molecularly Imprinted Solid-Phase Extraction and Liquid Chromatography for Biological Samples  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis focuses on the use of molecularly imprinted polymers as selective sorbents for solid-phase extraction (MISPE). The MISPE methods developed were mainly intended for use with biological samples, such as human urine and blood plasma. These body fluids are complex samples, which often need an effective clean-up step before analysis to reduce the levels of possible interfering substances from the matrix, especially if the analytes are present in trace amounts. Solid-phase extraction (S...

Mo?ller, Kristina

2006-01-01

57

Determination of sulfonamides in livers using matrix solid-phase dispersion extraction high-performance liquid chromatography.  

Science.gov (United States)

The matrix solid-phase dispersion (MSPD) was applied for extracting seven sulfonamides (SAs) in liver samples. The separation and determination were carried out by high-performance liquid chromatography. The analytes were derivated with fluorescamine and detected with fluorescence detector. The types of dispersion adsorbents for MSPD were examined and the highest recovery was obtained when the diatomaceous earth was used as the dispersion adsorbent and the mass ratio of dispersion adsorbent to sample was 3:1. The acetone was used as the elution solvent. Under the optimal conditions, the linear range for determining the SAs in liver samples was 5.0-1000.0 ng/g. The porcine, chicken and cattle liver samples were analyzed and the average recoveries of seven SAs were higher than 84.6%. PMID:22140007

Zhang, Yupu; Xu, Xu; Qi, Xiao; Gao, Wenquan; Sun, Shuo; Li, Xiaotian; Jiang, Chengfei; Yu, Aimin; Zhang, Hanqi; Yu, Yong

2012-01-01

58

Solid phase extraction of uranium(VI) onto benzoylthiourea-anchored activated carbon  

Energy Technology Data Exchange (ETDEWEB)

A new solid phase extractant selective for uranium(VI) based on benzoylthiourea anchored to activated carbon was developed via hydroxylation, amidation and reaction with benzoyl isothiocyanate in sequence. Fourier transform infrared spectroscopy and total element analysis proved that benzoylthiourea had been successfully grafted to the surface of the activated carbon, with a loading capacity of 1.2 mmol benzoylthiourea per gram of activated carbon. The parameters that affect the uranium(VI) sorption, such as contact time, solution pH, initial uranium(VI) concentration, adsorbent dose and temperature, have been investigated. Results have been analyzed by Langmuir and Freundlich isotherm; the former was more suitable to describe the sorption process. The maximum sorption capacity (82 mg/g) for uranium(VI) was obtained at experimental conditions. The rate constant for the uranium sorption by the as-synthesized extractant was 0.441 min{sup -1} from the first order rate equation. Thermodynamic parameters ({Delta}H{sup 0} = -46.2 kJ/mol; {Delta}S{sup 0} = -98.0 J/mol K; {Delta}G{sup 0} = -17.5 kJ/mol) showed the adsorption of an exothermic process and spontaneous nature, respectively. Additional studies indicated that the benzoylthiourea-anchored activated carbon (BT-AC) selectively sorbed uranyl ions in the presence of competing ions, Na{sup +}, Co{sup 2+}, Sr{sup 2+}, Cs{sup +} and La{sup 3+}.

Zhao Yongsheng; Liu Chunxia; Feng Miao; Chen Zhen; Li Shuqiong; Tian Gan; Wang Li; Huang Jingbo [College of Chemistry, Sichuan University, 29 Wangjiang Lu, Chengdu, 610064, Sichuan (China); Li Shoujian, E-mail: sjli000616@scu.edu.cn [College of Chemistry, Sichuan University, 29 Wangjiang Lu, Chengdu, 610064, Sichuan (China)

2010-04-15

59

Solid phase extraction of uranium(VI) onto benzoylthiourea-anchored activated carbon  

International Nuclear Information System (INIS)

A new solid phase extractant selective for uranium(VI) based on benzoylthiourea anchored to activated carbon was developed via hydroxylation, amidation and reaction with benzoyl isothiocyanate in sequence. Fourier transform infrared spectroscopy and total element analysis proved that benzoylthiourea had been successfully grafted to the surface of the activated carbon, with a loading capacity of 1.2 mmol benzoylthiourea per gram of activated carbon. The parameters that affect the uranium(VI) sorption, such as contact time, solution pH, initial uranium(VI) concentration, adsorbent dose and temperature, have been investigated. Results have been analyzed by Langmuir and Freundlich isotherm; the former was more suitable to describe the sorption process. The maximum sorption capacity (82 mg/g) for uranium(VI) was obtained at experimental conditions. The rate constant for the uranium sorption by the as-synthesized extractant was 0.441 min-1 from the first order rate equation. Thermodynamic parameters (?H0 = -46.2 kJ/mol; ?S0 = -98.0 J/mol K; ?G0 = -17.5 kJ/mol) showed the adsorption of an exothermic process and spontaneous nature, respectively. Additional studies indicated that the benzoylthiourea-anchored activated carbon (BT-AC) selectively sorbed uranyl ions in the presence of competing ions, Na+, Co2+, Sr2+, Cs+ and La3+.

60

Recovery evaluation of organophosphorus pesticides from bee pollen by matrix solid-phase dispersion extraction using sorbents based on silica and titania  

International Nuclear Information System (INIS)

This work focused on the evaluation of the recovery of organophosphorus pesticides from bee pollen after matrix solid phase-dispersion extraction (MSPD). Materials based on silica, titania and titania modified with polivylnylimidazole or polyestirene were used as adsorbents for the extraction of pesticides. Small amounts of fortified pollen (0.1 g, at 1 micro-g/g of pesticides), adsorbent (0.4 g) and solvent elution (1 mL de acetonitrile – ACN) were used in the extractions. For recovery evaluation, pollen extracts were analyzed by gas chromatography coupled with mass spectrometry.

 
 
 
 
61

Evaluation of Superparamagnetic Silica Nanoparticles for Extraction of Triazines in Magnetic in-Tube Solid Phase Microextraction Coupled to Capillary Liquid Chromatography  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The use of magnetic nanomaterials for analytical applications has increased in the recent years. In particular, magnetic nanomaterials have shown great potential as adsorbent phase in several extraction procedures due to the significant advantages over the conventional methods. In the present work, the influence of magnetic forces over the extraction efficiency of triazines using superparamagnetic silica nanoparticles (NPs) in magnetic in tube solid phase microextraction (Magnetic-IT-SPME) co...

Gonza?lez-fuenzalida, R. A.; Moliner-marti?nez, Y.; Helena Prima-Garcia; Antonio Ribera; Campins-falco?, P.; Zaragoza?, Ramon J.

2014-01-01

62

Adsorption and solid phase extraction of 8-hydroxyquinoline from aqueous solutions by using natural bentonite  

Energy Technology Data Exchange (ETDEWEB)

The nitrogen-heterocyclic compound 8-hydroxyquinoline (8HQ) is one of the components of coal tar and has a wide variety of uses in industry. Because of its toxicity for aquatic organisms and harmful effects for human health, the removal of 8HQ from aqueous solutions by adsorption onto natural bentonite was investigated in the present work. The experimental results show that the optimum pH value of 2.5 is favourable for the 8HQ adsorption. The experimental data were fitted well with the pseudo-second-order kinetic and Langmuir adsorption isotherm models at all studied temperatures. The maximum adsorption capacity obtained from the Langmuir isotherm model at 20 deg. C was 120.6 mg g{sup -1}. The calculated thermodynamic results such as {Delta}G{sup o} (-24.3 kJ mol{sup -1}) and {Delta}H{sup o} (-9.56 kJ mol{sup -1}) indicate that the adsorption process is spontaneous and exothermic in nature. Solid phase extraction of 8HQ was also performed. The X-ray diffractometry (XRD), Fourier Transform Infrared (FTIR) and thermogravimetric (TG) analyses were carried out in order to confirm the 8HQ adsorption onto bentonite. According to the obtained results, natural bentonite can be a reusable and effective adsorbent for the removal of 8HQ.

Erdem, Bilge; Ozcan, Adnan [Department of Chemistry, Faculty of Science, Anadolu University, Yunusemre Campus, 26470 Eskisehir (Turkey); Ozcan, A. Safa, E-mail: asozcan@anadolu.edu.tr [Department of Chemistry, Faculty of Science, Anadolu University, Yunusemre Campus, 26470 Eskisehir (Turkey)

2010-06-15

63

Detection of ibuprofen and ciprofloxacin by solid-phase extraction and UV/Vis spectroscopy  

Science.gov (United States)

A simple and economic solid-phase extraction coupled with UV/Vis spectrophotometric method is described for the analysis of ibuprofen and ciprofloxacin. Following solid-phase extraction from model wastewater samples containing standard ibuprofen or ciprofloxacin, elutes were analyzed by a UV/Vis spectrophotometer at 225 nm for ibuprofen and 280 nm for ciprofloxacin. The assay was linear for both compounds with good coefficients of correlation. This method shows good recoveries for both compounds with 101.0 ± 9.8% for ibuprofen and 99.4 ± 11.8% ciprofloxacin.

Zhou, Zhengwei; Jiang, Jia Qian

2012-07-01

64

Temperature-swing solid-phase extraction of heavy metals on a poly(N-isopropylacrylamide) hydrogel.  

Science.gov (United States)

The feasibility of temperature-swing adsorption of heavy metals on a thermosensitive N-isopropylacrylamide (NIPA) hydrogel was examined. We have proposed a novel temperature-swing solid-phase extraction (TS-SPE) technique. First, a metal ion in an aqueous solution is complexed with an extractant. Subsequently, the metal-extractant complexes (or micelles) are adsorbed onto the NIPA hydrogel through a hydrophobic interaction above the lower critical solution temperature (LCST). Finally, the metal-extractant complexes are desorbed from the NIPA hydrogel after it is cooled below the LCST. In a model system consisting of Cu(II) ions, sodium n-dodecylbenzenesulfonate (SDBS), and NIPA hydrogel, the proposed TS-SPE technique has been successfully conducted. The following observations can be made: the amount of adsorbed Cu(II) ions increases with the increase in temperature, the maximum adsorption is attained at a temperature above the LCST, and the hydrogel adsorbs and desorbs Cu(II) ions reversibly due to the temperature-swing between 10 and 40 degrees C. The LCSTs of poly(NIPA) in aqueous SDBS solutions with/without CuCl2 and the surface tensions of their solutions suggest that the hydrophobicity of the complex Cu(DBS)2 is greater than the hydrophobicities of SDBS and DBS. In addition to the separation of heavy metals, TS-SPE is potentially applicable to cases such as the separation of biological molecules by means of metal-ion affinity. PMID:17999542

Tokuyama, Hideaki; Iwama, Takahiko

2007-12-18

65

Selective extraction of triazine herbicides based on a combination of membrane assisted solvent extraction and molecularly imprinted solid phase extraction.  

Science.gov (United States)

A selective extraction technique based on the combination of membrane assisted solvent extraction and molecularly imprinted solid phase extraction for triazine herbicides in food samples was developed. Simazine, atrazine, prometon, terbumeton, terbuthylazine and prometryn were extracted from aqueous food samples into a hydrophobic polypropylene membrane bag containing 1000?L of toluene as the acceptor phase along with 100mg of MIP particles. In the acceptor phase, the compounds were re-extracted onto MIP particles. The extraction technique was optimised for the type of organic acceptor solvent, amount of molecularly imprinted polymers particles in the organic acceptor phase, extraction time and addition of salt. Toluene as the acceptor phase was found to give higher triazine binding onto MIP particles compared to hexane and cyclohexane. Extraction time of 120min and 100mg of MIP were found to be optimum parameters. Addition of salt increased the extraction efficiency for more polar triazines. The selectivity of the technique was demonstrated by extracting spiked cow pea and corn extracts where clean chromatograms were obtained compared to only membrane assisted solvent extraction or only molecularly imprinted solid phase extraction. The study revealed that this combination may be a simple way of selectively extracting compounds in complex samples. PMID:21190688

Chimuka, Luke; van Pinxteren, Manuela; Billing, Johan; Yilmaz, Ecevit; Jönsson, Jan Åke

2011-02-01

66

Use of Solid Phase Extraction in the Biochemistry Laboratory to Separate Different Lipids  

Science.gov (United States)

Solid-phase extraction (SPE) was used to demonstrate how various lipids and lipid classes could be separated in a biochemistry laboratory setting. Three different SPE methods were chosen on their ability to separate a lipid mixture, consisting of a combination of a either a fatty acid, a triacylglycerol, a mono- or diacylglycerol, phospholipid,…

Flurkey, William H.

2005-01-01

67

COMPARISON OF TWO DIFFERENT SOLID PHASE EXTRACTION/LARGE VOLUME INJECTION PROCEDURES FOR METHOD 8270  

Science.gov (United States)

Two solid phase (SPE) and one traditional continuous liquid-liquid extraction method are compared for analysis of Method 8270 SVOCs. Productivity parameters include data quality, sample volume, analysis time and solvent waste. One SPE system, unique in the U.S., uses aut...

68

AUTOMATED SOLID PHASE EXTRACTION GC/MS FOR ANALYSIS OF SEMIVOLATILES IN WATER AND SEDIMENTS  

Science.gov (United States)

Data is presented on the development of a new automated system combining solid phase extraction (SPE) with GC/MS spectrometry for the single-run analysis of water samples containing a broad range of organic compounds. The system uses commercially available automated in-line sampl...

69

Development of a Solid Phase Extraction Method for Agricultural Pesticides in Large-Volume Water Samples  

Science.gov (United States)

An analytical method using solid phase extraction (SPE) and analysis by gas chromatography/mass spectrometry (GC/MS) was developed for the trace determination of a variety of agricultural pesticides and selected transformation products in large-volume high-elevation lake water sa...

70

A simplified radiometabolite analysis procedure for PET radioligands using a solid phase extraction with micellar medium  

International Nuclear Information System (INIS)

A solid phase extraction method has been developed for simple and high-speed direct determination of PET radioligands in plasma. Methods: This methodology makes use of a micellar medium and a solid-phase extraction cartridge for displacement of plasma protein bound radioligand and separation of PET radioligands from their radiometabolites without significant preparation. The plasma samples taken from monkey or human during PET measurements were mixed with a micellar eluent containing an anionic surfactant sodium dodecyl sulphate and loaded onto SPE cartridges. The amount of radioactivity corresponding to parent radioligand (retained on the cartridge) and its radioactive metabolites (eluted with micellar eluent) was measured. Results: Under the optimized conditions, excellent separation of target PET radioligands from their radiometabolites was achieved with a single elution and short run-time of 1 min. This method was successfully applied to study the metabolism for 11C-labelled radioligands in human or monkey plasma. The amount of parent PET radioligands estimated by micellar solid phase extraction strongly corresponded with that determined by radio-LC. The improved throughput permitted the analysis of a large number of plasma samples (up to 13 samples per one PET study) for accurate estimation of metabolite-corrected input function during quantitative PET imaging studies. Conclusion: Solid phase extraction together with micellar medium is fast, sensitive and easy to use, and therefore it is an attractive alternative method to determine relative composition of PET radioligands in plasma

71

Analysis of free fatty acids in beer: comparison of solid-phase extraction, solid-phase microextraction, and stir bar sorptive extraction.  

Science.gov (United States)

Solid-phase extraction (SPE), solid-phase microextraction (SPME) using carbowax/divinylbenzen fiber, and stir bar sorptive extraction (SBSE) followed by solvent back extraction have been used for the extraction of free fatty acids (caproic, caprylic, pelargonic, capric, lauric, myristic, palmitic, stearic, oleic, linoleic, and linolenic acids) from beer. Subsequent gas chromatographic analyses with flame ionization detection were used for the determination of these compounds. Medium-chain fatty acids (caproic-lauric acid) were determined as free acids, and long-chain fatty acids (myristic-linolenic acids) were determined as methyl esters after methylation by BF(3)-methanol 14%. Linearity, recovery, and repeatability of all methods have been determined and compared with the SPE method used as a reference (SPME method was used only for medium-chain fatty acid determination). All three procedures provide similar working parameters characterized by high repeatability (2.3-16.3%) and good linearity (correlation coefficient ranging from 0.9919 to 0.9999). Results of beer analyses obtained by using these three methods were highly correlated. Although all methods provide compatible alternatives, for medium-chain fatty acid analysis SPME may be a more appropriate technique due to its operational simplicity, repeatability, and low cost. PMID:19904941

Horák, Tomás; Culík, Jirí; Cejka, Pavel; Jurková, Marie; Kellner, Vladimír; Dvorák, Josef; Hasková, Danusa

2009-12-01

72

Extraction of Genomic DNA Using Magnetic Nanoparticles (Fe3O4 as a Solid-Phase Support  

Directory of Open Access Journals (Sweden)

Full Text Available Magnetic separation technology, using magnetic particles, is quick and easy method for sensitive and reliable captures of specific proteins, genetic material and other biomolecules. The current paper describes a universal genomic DNA extraction method optimized in our laboratory using magnetic nanoparticles as a solid phase adsorbent. The yields of the isolated DNA with magnetic method were higher or equivalent to the conventional procedures in all the samples tested. Additionally, the magnetic method takes less than 15 minutes to extract DNA as against several hours taken by conventional protocols. Furthermore, the isolated DNA was found to function satisfactorily in PCR amplification and restriction endonuclease digestion. The developed procedure is simple, quick, cheap, robust and does not require the use of organic solvents or sophisticated equipments; thereby making it more amenable to automation.

Z. M. Saiyed

2007-01-01

73

Ethanol/Water extraction combined with solid-phase extraction and solid-phase microextraction concentration for the determination of chlorophenols in cork stoppers.  

Science.gov (United States)

The appearance of 2,4,6-trichloroanisole (TCA) in cork stoppers is of great concern because it can cause off-flavors in bottled wine. To prevent this sensorial defect, there should not be any traces of 2,4,6-trichlorophenol (TCP), 2,3,4,6-tetrachlorophenol (TeCP), or pentachlorophenol (PCP) in the finished corks, because they are the direct precursors of TCA. In the course of this study two methodologies based upon an extraction with ethanol/water mixtures to determine the chlorophenolic content in cork matrices were developed. The cork extract is preconcentrated using both solid-phase extraction and solid-phase microextraction methodologies. The latter was optimized by applying a full two-level factorial design. Finally, spiked ground corks at nanogram per gram levels of each chlorophenol were analyzed under optimal conditions and by applying both procedures. The obtained results demonstrate that chlorophenols can be detected in corks contaminated at the nanogram per gram level and, thus, these approaches can be successfully applied as quality control measures in the cork industry. PMID:16448159

Insa, Sara; Besalú, Emili; Iglesias, Cristina; Salvadó, Victoria; Anticó, Enriqueta

2006-02-01

74

Solid-phase extraction of antioxidant compounds from commercial cranberry extract and its antiradical activity  

Directory of Open Access Journals (Sweden)

Full Text Available This study is concerned with the fractionation and determination of major antioxidant compounds (phenols, flavonoids, anthocyanins and vitamin C in commercial cranberry extract. The total content of phenolics, flavonoids and total and monomers of anthocyanins, determined spectrophotometrically, was 1.67 mg/g, 0.41 mg/g, 5.12 mg/g and 3.32 mg/g. The content of vitamin C, determined volumetrically, was 121.74 mg/g. Commercial cranberry extract was dissolved in 80 % acetone and the solution was fractionated using solid phase extraction (SPE in order to abstract vitamin C, neutral and acidic phenols. The free radical scavenging activity of the cranberry extract and its fractions was investigated on stable 2,2-diphenyl-1-picrylhydrazyl (DPPH and reactive hydroxyl radicals employing electron spin resonance (ESR spectroscopy. The most effective fractions were those containing vitamin C (AADPPH= AAOH=100%, neutral (AADPPH=89.50% and AAOH=43.11% and acidic (AADPPH=83.98% and AAOH=38.58% phenols. The presence of vitamin C, abstracted from cranberry extract, was determined by Fe(III-mediated ascorbate oxidation which yields characteristic ESR doublet spectrum of ascorbyl radical.

Tumbas Vesna T.

2007-01-01

75

BIOASSAY AND CHEMICAL ANALYSIS OF AMBIENT AIR PARTICULATE EXTRACTS FRACTIONATED BY USING NONAQUEOUS ANION-EXCHANGE SOLID PHASE EXTRACTION  

Science.gov (United States)

A nonaqueous anion-exchange solid-phase extraction technique has been developed for analyzing particulate extracts of ambient air samples and combustion source samples. he technique has been used for sample preparation and sample prefractionation in bioassay-directed fractionatio...

76

Molecularly imprinted polymer solid-phase extraction for detection of zearalenone in cereal sample extracts.  

Science.gov (United States)

The aim of this work was to develop a method for the clean-up and preconcentration of zearalenone from corn and wheat samples employing molecularly imprinted polymer (MIP) as selective sorbent for solid-phase extraction (SPE). Cereal samples were extracted with acetonitrile/water (75:25, v/v) and the extract was diluted with water and applied to an AFFINIMIP ZON MIP-SPE column. The column was then washed to eliminate the interferences and zearalenone was eluted with methanol and quantified using HPLC with fluorescence detection (lambda(exc)=275/lambda(em)=450 nm). The precision and accuracy of the method were satisfactory for both cereals at the different fortification levels tested and it gave recoveries between 82 and 87% (RSDr 2.5-6.2%, n=3) and 86 and 90% (RSDr 0.9-6.8%, n=3) for wheat and maize, respectively. MIP-SPE column capacity was determined to be not less than 6.6 microg of zearalenone and to be at least four times higher than that of immunoaffinity column (IAC). The application of AFFINIMIP ZON molecularly imprinted polymer as a selective sorbent material for detection of zearalenone fulfilled the method performance criteria required by the Commission Regulation (EC) No. 401/2006, demonstrating the suitability of the technique for the control of zearalenone in cereal samples. PMID:20579483

Lucci, Paolo; Derrien, Delphine; Alix, Florent; Pérollier, Céline; Bayoudh, Sami

2010-07-01

77

Silica supported Fe(3)O(4) magnetic nanoparticles for magnetic solid-phase extraction and magnetic in-tube solid-phase microextraction: application to organophosphorous compounds.  

Science.gov (United States)

This work demonstrates the application of silica supported Fe3O4 nanoparticles as sorbent phase for magnetic solid-phase extraction (MSPE) and magnetic on-line in-tube solid-phase microextraction (Magnetic-IT-SPME) combined with capillary liquid chromatography-diode array detection (CapLC-DAD) to determine organophosphorous compounds (OPs) at trace level. In MSPE, magnetism is used as separation tool while in Magnetic-IT-SPME, the application of an external magnetic field gave rise to a significant improvement of the adsorption of OPs on the sorbent phase. Extraction efficiency, analysis time, reproducibility and sensitivity have been compared. This work showed that Magnetic-IT-SPME can be extended to OPs with successful results in terms of simplicity, speed, extraction efficiency and limit of detection. Finally, wastewater samples were analysed to determine OPs at nanograms per litre. PMID:24105458

Moliner-Martinez, Y; Vitta, Yosmery; Prima-Garcia, Helena; González-Fuenzalida, R A; Ribera, Antonio; Campíns-Falcó, P; Coronado, Eugenio

2014-03-01

78

Determination of volatile compounds in grape distillates by solid-phase extraction and gas chromatography.  

Science.gov (United States)

Solid-phase extraction (SPE) procedure on octadecylsilica (C18) was developed for accumulation of volatile compounds from grape distillates. The procedure was optimised for final analysis by capillary gas chromatography. At mass concentrations in model solutions ranging from 0.1 to 50 mg/l solid-phase extraction recoveries of all analytes ranged from 69% for 2-phenylethanol to 102% for capric acid, with RSD values from 2 to 9%. SPE recoveries of internal standards to be added in the sample solution prior to extraction, higher alcohols 2-ethyl-1-hexanol and 1-undecanol, were 97 and 93%, respectively, with RSD values of 3%. Detection limits of analyzed compounds in model solutions ranged from 0.011 mg/l for isoamyl acetate to 0.037 mg/l for caproic acid. Method efficiency was tested in relation to acetic acid content, volume fraction of ethanol and possible matrix effects. A significant influence of matrix on SPE efficiency for geraniol, cis-2-hexen-1-ol and cis-3-hexen-1-ol was detected. For the same reason, 2-phenylethanol could not be determined by developed SPE method in samples of grape distillates. The developed solid-phase extraction method was successfully applied to determine the differences in volatile compound content in different grape distillates produced by the distillation of crushed, pressed and fermented grapes. PMID:16216256

Luki?, Igor; Banovi?, Mara; Persuri?, Dordano; Radeka, Sanja; Sladonja, Barbara

2006-01-01

79

Halogen bonding: A new retention mechanism for the solid phase extraction of perfluorinated iodoalkanes  

International Nuclear Information System (INIS)

Highlights: ? Halogen bonding (XB) is firstly utilised in solid phase extraction. ? The perfluorinated iodine alkanes can be extracted by C-I?Cl? halogen bonding. ? The C-I?Cl? halogen bond is well characterised by spectroscopy methods. ? The analytes with strong halogen-bonding abilities can be selectively extracted. - Abstract: For the first time, halogen-bonding interaction is utilised in the solid phase extraction of perfluorinated iodoalkane (PFI). Nine PFIs, as model analytes, were tested, and analyses by UV, 19F NMR and Raman spectroscopies demonstrate that the PFIs are extracted by a strong anion exchange (SAX) sorbent from n-hexane due to the C-I?Cl? halogen-bonding interactions. The results also show that the adsorptivities of SAX for the diiodoperfluoro-alkanes (diiodo-PFIs) were much stronger than those for the perfluoroalkyl iodides (monoiodo-PFIs). Specifically, the recoveries for 1,6-diiodoperfluorohexane and 1,8-diiodoperfluorooctane were higher than 80% when 100 mL of sample spiked with a 5 ng mL?1 analyte mixture was extracted. Interestingly, SAX had no adsorption for hexafluorobenzene at all, which is known to be unable to form a halogen bond with Cl?. The analytical performance of the halogen bond-based SPE-GC–MS method for the diiodo-PFIs was also examined in soil samples. The sorbent SAX enabled the selective extraction of four diiodo-PFIs successfully frosuccessfully from soil samples. The recoveries of the diiodo-PFIs extracted from 5 g soil sample at the 100 ng g?1 spike level were in the range of 73.2–93.8% except 26.8% for 1,2-diiodoperfluoroethane. The limit of detection varied from 0.02 to 0.04 ng g?1 in soil samples. Overall, this work reveals the great application potential of halogen bonding in the field of solid phase extraction to selectively extract compounds with strong halogen-bonding abilities.

80

Solid-phase extraction clean-up of ciguatoxin-contaminated coral fish extracts for use in the mouse bioassay  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Florisil solid-phase extraction (SPE) cartridges were used for purifying ciguatoxin-contaminated (CTX-contaminated) coral fish extracts, with an aim to removing extracted lipid but retaining optimal level of CTXs in the purified fractions. CTX-containing fraction (target fraction) in fish ether extract was isolated and purified by eluting through a commercially available Florisil cartridge with hexane-acetone-methanol solvent mixtures of increasing polarity (hexane-acetone...

2009-01-01

 
 
 
 
81

Determination of Phthalate Esters in Drinking Water using Solid-phase Extraction and Gas Chromatography  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Phthalate esters are widely used as plasticizer. They can migrate from plastic materials to the environment. Some of these compounds may have risk to get cancer. Phthalate esters; dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP) and bis(2-ethylhexyl) phthalate (DEHP) were extracted simultaneously using solid-phase and analyzed by gas chromatograph. The percentage recoveries were carried out on LC-18 and Florisil cartridge using various eluting solvent. The 6 mL Flori...

Kanchanamayoon, W.; Prapatpong, P.

2010-01-01

82

VOLATILE COMPOUNDS OF LITHRAEA CAUSTICA (LITRE) DETERMINATED BY SOLID PHASE MICRO-EXTRACTION (SPME)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The head space of the aerial parts of Lithraea caustica was analyzed by Solid Phase Micro-Extraction (SPME) technique, obtaining as main volatile compounds the monoterpenes, myrcene, a -pinene, , p-cymene and limonene, as well as the sesquiterpene caryophylene.De las partes áereas de Lithraea caustica y usando la técnica de Micro-Extracción en Fase Sólida (MEFS), fueron identificados y cuantificados los principales compuestos volátiles: los monoterpenos, mirceno, a -pineno, p-cimeno ...

Garbarino, Juan A.; GIUSEPPE SALVATORE; MARISA PIVANOVO; MARÍA CRISTINA CHAMY; MARCELLO NICOLETTI; ALFREDO DE IOANNES

2002-01-01

83

Determination of organophosphorus pesticides using molecularly imprinted polymer solid phase extraction  

International Nuclear Information System (INIS)

Molecularly imprinted polymer solid phase extraction (MIP-SPE) method has been developed for the determination of organophosphorus pesticides (OPPs) in water samples. The MIP was prepared by thermo-polymerization method using methacrylic acid (MAA) as functional monomer, ethylene glycol dimethacrylate (EGDMA) as crosslinker, acetonitrile as porogenic solvent and quinalphos as the template molecule. The three OPPs (diazinon, quinalphos and chloropyrifos) were selected as target analytes as they are widely used in agriculture sector. Various parameters affecting the extraction efficiency of the imprinted polymers have been evaluated to optimize the selective preconcentration of OPPs from aqueous samples. The characteristics of the MIP-SPE method were validated by high performance liquid chromatography (HPLC). The accuracy and selectivity of the MIP-SPE process developed were verified using non-imprinted polymer solid phase extraction (NIP-SPE) and a commercial C18-SPE was used for comparison. The recoveries of the target analytes obtained using the MIPs as the solid phase sorbent ranged from 83% to 98% (RSDs 1.05 - 1.98 %; n=3) for water sample. The developed MIP-SPE method demonstrates that it could be applied for the determination of OPPs in water samples. (author)

84

Preconcentration and separation of nickel, copper and cobalt using solid phase extraction and their determination in some real samples  

Energy Technology Data Exchange (ETDEWEB)

A solid phase extraction method has been developed to separate and concentrate trace amounts of nickel, cobalt and copper ions from aqueous samples for the measurement by flame atomic absorption spectrometry. By the passage of aqueous samples through activated carbon modified by dithioxamide (rubeanic acid) (DTO), Ni{sup 2+}, Cu{sup 2+} and Co{sup 2+} ions adsorb quantitatively. The recoveries of analytes at pH 5.5 with 500 mg solid phase were greater than 95% without interference from alkaline, earth alkaline and some metal ions. The enrichment factor was 330. The detection limits by three sigma were 0.50 {mu}g L{sup -1} for copper, 0.75 {mu}g L{sup -1} for nickel and 0.80 {mu}g L{sup -1} for cobalt. The loading capacity was 0.56 mg g{sup -1} for Ni{sup 2+}, 0.50 mg g{sup -1} for Cu{sup 2+} and 0.47 mg g{sup -1} for Co{sup 2+}. The presented procedure was applied to the determination of analytes in tap, river and sea waters, vegetable, soil and blood samples with successfully results (recoveries greater than 95%, R.S.D. lower than 2% for n = 3)

Ghaedi, M. [Chemistry Department, University of Yasouj, Yasouj 75914-353 (Iran, Islamic Republic of)]. E-mail: m_ghaedi@mail.yu.ac.ir; Ahmadi, F. [Gachsaran Azad University, Gachsaran (Iran, Islamic Republic of); Soylak, M. [Chemistry Department, University of Erciyes, 38039 Kayseri (Turkey)

2007-08-17

85

Dispersive micro-solid phase extraction based on self-assembling, ionic liquid-coated magnetic particles for the determination of clofentezine and chlorfenapyr in environmental water samples.  

Science.gov (United States)

Two ionic liquid-coated-Fe3O4 magnetic particles (IL-Fe3O4 MPs) were developed for use in two types of dispersive micro-solid phase extraction (D-?-SPE) for the high-performance liquid chromatographic analysis of clofentezine and chlorfenapyr in environmental water samples. Self-assembling IL-Fe3O4 MPs were used in D-?-SPE as adsorbents. Two D-?-SPE extraction methods, namely, direct dispersive micro-solid phase extraction (d-D-?-SPE) and in situ solvent formation-based dispersive micro-solid phase extraction (ISF-D-?-SPE), were proposed, using [C8MIM][PF6] to extract analytes through two pathways. Lower IL doses were required in the extraction process compared with those in other IL-based methods. Fe3O4 MPs can also be recycled and reused after extraction and are thus environmentally friendly. These newly developed methods were demonstrated to be feasible for use in the quantitation of clofentezine and chlorfenapyr at trace levels, with lower limit of detection values ranging from 0.4 to 0.5 ng mL(-1) for d-D-?-SPE and 0.4 ng mL(-1) for ISF-D-?-SPE. Finally, relative standard deviations of less than 6.0% were obtained. PMID:24060962

Peng, Bing; Zhang, Jiaheng; Lu, Runhua; Zhang, Sanbing; Zhou, Wenfeng; Gao, Haixiang

2013-11-21

86

Extraction en phase solide (SPE : théorie et applications Solid phase extraction (SPE: theory and applications  

Directory of Open Access Journals (Sweden)

Full Text Available L’extraction en phase solide (SPE est devenue depuis quelques années une technique de préparation d’échantillons de plus en plus utilisée en toxicologie analytique. Son principe de base est analogue à celui de la chromatographie de partage. Depuis son apparition de nombreuses phases stationnaires ont été développées par les industriels, permettant des extractions de plus en plus ciblées, ou bien adaptées pour l’extraction d’un grand nombre de substances de natures chimiques variées : pour une recherche large de xénobiotiques en milieu hospitalier pour des patients admis aux urgences ou en médecine légale dans les recherches des causes de la mort. De par la diversité des phases stationnaires elle permet l’extraction de composés polaires difficilement extractibles auparavant par les phases organiques. L’extraction se déroule généralement en quatre étapes : le conditionnement de la phase stationnaire, le chargement de l’échantillon, le(s lavage(s de la cartouche et enfin l’élution. La maîtrise de ce pré-analytique permet des facteurs de pré-concentration de(s analyte(s à rechercher ou à doser qui peut abaisser la limite de détection d’une méthode. Les larges gammes commercialisées par les industriels sont adaptées à des extractions ponctuelles de volumes très variés (de quelques dizaines de microlitres à plusieurs millilitres voire litres mais aussi à l’extraction de grandes séries grâce à des plaques de 96 puits. C’est aussi une technique qui a l’avantage d’être automatisable. De très nombreuses méthodes analytiques ont été développées sur les matrices biologiques habituelles : le sérum, le plasma ou les urines mais également dans des matrices plus complexes comme les cheveux ou le méconium. Solid phase extraction (SPE has become, in recent years, a technique for sample preparation increasingly used in analytical toxicology. Its basic principle is similar to that of partition chromatography. Since its appearance, many stationary phases have been developed by industry for more targeted extractions or adapted for the extraction of a large number of chemical substances of various kinds for a wide search for xenobiotics in hospital for patients admitted to the emergency ward, or forensic research into the causes of death. Because of the variety of stationary phases it allows the extraction of polar compounds from previously difficult to extract organic phases. The extraction is generally conducted in four steps: conditioning of the stationary phase, loading of the sample, washing(s of the cartridge and finally, elution. Control of this pre-analytical stage allows factors of pre-concentration of the analyte(s to search for or to be determined which can lower the limit of detection of a method. The wide ranges marketed by the industry are suitable for specific extraction of very varied volumes (a few tens of microliters up to several mL or liters but also for extraction of large sets with plates of 96 wells. It is also a technique which has the advantage of being automated. Many analytical methods have been developed on biological matrices: serum, plasma and urine, but also in more complex matrices such as hair and meconium.

Humbert Luc

2010-05-01

87

Molecularly imprinted polymer microspheres for solid-phase extraction of protocatechuic acid in Rhizoma homalomenae.  

Science.gov (United States)

Molecularly imprinted polymers (MIPs) had been prepared by precipitation polymerization method using acrylamide as the functional monomer, ethylene glycol dimethacrylate as the cross-linker, acetonitrile as the porogen solvent and protocatechuic acid (PA), one of phenolic acids, as the template molecule. The MIPs were characterized by scanning electron microscopy and Fourier transform infrared, and their performance relative to non-imprinted polymers was assessed by equilibrium binding experiments. Six structurally similar phenolic acids, including p-hydroxybenzoic acid, gallic acid, salicylic acid, syringic acid, vanillic acid, ferulic acid were selected to assess the selectivity and recognition capability of the MIPs. The MIPs were applied to extract PA from the traditional Chinese medicines as a solid-phase extraction sorbent. The resultant cartridge showed that the MIPs have a good extraction performance and were able to selectively extract almost 82% of PA from the extract of Rhizoma homalomenae. Thus, the proposed molecularly imprinted-solid phase extraction-high performance liquid chromatography method can be successfully used to extract and analyse PA in traditional Chinese medicines. PMID:21809445

Chen, Fang-Fang; Wang, Guo-Ying; Shi, Yan-Ping

2011-10-01

88

Solid phase extraction of uranium (VI) using penicillium chrysogenum immobilized on silica gel  

International Nuclear Information System (INIS)

Uranium is a metal of strategic importance in the area of Nuclear Technology. It has due to its usage in power generation. Being a toxic element and due to environmental concerns its determination from water, soil and other samples has gained significance. The determination of traces of uranium in such samples requires a preconcentration step. Biosorption methods involving solid phase extraction utilizes various materials of biological origin, including bacteria, fungi, yeast, algae, etc. In the present work a solid phase extraction method for separation and enrichment of uranium (VI) was developed. A solid phase was prepared by immobilization 150 mg of Penicillium and 1.0 g silica. A 350 mg of Penicillium chrysogenum immobilized silica mixed with double distilled water packed in a glass column (150 mm length and 10 mm internal diameter) with wool as support and was systematically investigated to optimize the conditions for quantitative sorption and desorption of uranium (VI). It was determined spectrophotometrically using Arsenazo (III) at 650 nm

89

Speciation of inorganic arsenic in environmental waters using magnetic solid phase extraction and preconcentration followed by ICP-MS  

International Nuclear Information System (INIS)

A new method was developed for the speciation of inorganic arsenic in environmental water by using selective magnetic solid-phase extraction followed by inductively coupled plasma mass spectrometry. It is found that As(V) selectively adsorbed on amino-modified silica-coated magnetic nanoparticles (MNPs) in the pH range from 3 to 8, while As(III) is not be retained. The As(V)-loaded MNPs can be separated easily from the aqueous sample solution by simply applying an external magnetic field. The adsorbed As(V) was quantitatively recovered from the MNPs using using 1 M nitric acid. Total inorganic As was extracted after the permanganate oxidation of As(III) to As(V). Parameters affecting the separation were investigated systematically, and the optimal separation conditions were established. Under the optimal conditions, the limit of detection is 0.21 ng L-1, and the precision is 6.8% (at 10 ng L-1, for n = 7). The method was applied to the speciation of inorganic arsenic in environmental water of tobacco growing area. (author)

90

Synthesis and evaluation of silver nanoparticles material for solid phase extraction of cobalt from water samples  

Science.gov (United States)

In this study, a new solid phase extractor, nano-scale silver particles were synthesized. The silver nanoparticle-based solid phase extraction was used for separation and preconcentration of the trace amount of cobalt ion from various water samples prior to its determination by flame atomic absorption spectrometry. The effects of various parameters, including pH, amount of complexing agent [1-(2-pyridylazo)-2-naphthol] (PAN), flow rates of solution and eluent, type and least amount of the eluent for elution of the cobalt from silver nanoparticles were studied and optimized. Under the optimum conditions, the detection limit of this procedure was 0.78 ?g L-1, and the relative standard deviation (RSD%) was 3.1% ( n = 10, c = 20 ?g L-1). This method was applied to the determination of cobalt in water samples.

Khajeh, Mostafa; Sanchooli, Esmael

2011-12-01

91

[Selective enrichment of iridoid glucosides in Hedyotis diffusa Willd. by tandem solid phase extraction].  

Science.gov (United States)

A method for selective enrichment of iridoid glucosides in Hedyotis diffusa Willd. by tandem solid phase extraction (SPE) was developed. Oligo(ethylene glycol) (OEG) is a novel type of separation material made in this laboratory. The differences of the surface chemical structures between OEG material and ODS material resulted in their different retention capabilities for iridoid glucosides. Based on the differences, an OEG-ODS solid phase extraction method was designed for selective enrichment of iridoid glucosides. The water extract (150.28 mg) of Hedyotis diffusa Willd. was precipitated by ethanol, and an aliquot (27.03 mg) of the product from the supernatant solution was loaded onto an OEG cartridge and rinsed by 5 mL water. Then, the rinsing solution was loaded onto an ODS cartridge. After it was washed by 5 mL water and eluted by 5 mL methanol, 4.01 mg final product was obtained from the methanol eluent. All the products were characterized by ultra performance liquid chromatography (UPLC), and 14 representative peaks of iridoid glucosides were found. The enrichment results were proved effective by directly comparing the chromatograms each step. To further characterize the enrichment efficiency, the changes of the peak area of iridoid glucosides were investigated. The results showed that the content of 14 iridoid glucosides in the final product reached 6.10 times its original proportion in water extraction product and their recovery was 50.1% on average. Therefore, the iridoid glucosides can be enriched by the tandem solid phase extraction method from water extracting-ethanol precipitating solution of Hedyotis diffusa Willd. with a good selectivity and an acceptable recovery. The proposed method has the advantages of high enrichment efficiency and simple operation. PMID:19938499

Zhang, Feng; Guo, Zhimou; Zhang, Feifang; Xue, Xingya; Liang, Xinmiao

2009-07-01

92

On-line coupling of solid-phase extraction to liquid chromatography--a review.  

Science.gov (United States)

Solid-phase extraction (SPE) is an effective sample preparation method for removal of interfering compound and enrichment of analyte. Liquid chromatography (LC) with various detectors is a main separation and detection technique used in the analytical field. This article reviews the literatures about the on-line coupling of SPE with LC. The advantages of on-line coupling are reduction of analysis time, sample contamination, and analyte losses, as well as improvement of precision and accuracy. The SPE sorbents including traditional materials, such as chemically bonded silica, ion-exchange and carbon-based materials, and some novel sorbents, such as restricted access material, molecularly imprinted polymer, immunosorbent, and monolithic material, used in the on-line analysis are discussed in detail. The on-line coupling of SPE-LC to other sample preparation techniques, such as supercritical fluid extraction, subcritical water extraction, microwave-assisted extraction, ultrasound-assisted extraction, and derivatization technique are also reviewed. PMID:19772737

Chen, Ligang; Wang, Hui; Zeng, Qinglei; Xu, Yang; Sun, Lei; Xu, Haoyan; Ding, Lan

2009-09-01

93

Analysis of ecologically relevant pharmaceuticals in wastewater and surface water using selective solid phase extraction and UPLC/MS/MS  

Science.gov (United States)

A rapid and sensitive method has been developed for the analysis of 48 human prescription active pharmaceutical ingredients (APIs) and 6 metabolites of interest, utilizing selective solid-phase extraction (SPE) and ultra performance liquid chromatography in combination with tripl...

94

Matrix solid-phase dispersion versus ultrasound assisted extraction with solid-phase extraction in the HPLC analysis of furanocoumarins from fruits of Archangelica officinalis Hoffm  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Neste estudo, um eficiente método, a dispersão da matriz em fase sólida (DMFS), foi usado para a determinação simultânea de furanocoumarinas de frutos de Archangelica officinalis Hoffm. Amostras da planta foram preparadas pelo procedimento MSPD otimizado, utilizando C18 como sorvente. A análise foi [...] realizada por cromatografia líquida de alta eficiência com detector de arranjo de diodos (HPLC-DAD). A eficiência do método DMFS também foi comparada com a extração assistida por ultra-som associada à extração em fase sólida (SPE com USAE). O MSPD extraiu furanocoumarins (isoimperatorin, imperatorin, bergapteno, isopimpinellin, xantotoxina, umbeliferona e xanthotoxol) de Archangelica officinalis com recuperações satisfatórias que variam de 91,43 a 96,07% e desvio padrão relativo menor do que 4,34% . O limite de detecção das várias furanocoumarinas, encontra-se na faixa de 0,37 mg mL-1 para a xanthotoxol e 10,82 mg mL-1 para imperatorin. Os resultados apresentados no manuscrito revelam que o método DMFS é eficiente, simples, rápido e de fácil execuçaõ, e é adequado para o isolamento de furanocoumarins a partir da plantas. Abstract in english In this study an efficient matrix solid-phase dispersion (MSPD) method for the simultaneous HPLC analysis of furanocoumarins from fruits of Archangelica officinalis Hoffm. was performed. Herbal samples were prepared by an optimized MSPD procedure using C18 as sorbent. The analysis was performed by h [...] igh performance liquid chromatography with diode array detector (HPLC-DAD). The efficiency of the MSPD method was also compared with ultrasound assisted extraction with solid-phase extraction (USAE with SPE). The MSPD extracted furanocoumarins (isoimperatorin, imperatorin, bergapten, isopimpinellin, xanthotoxin, umbelliferone and xanthotoxol) from Archangelica officinalis with satisfactory recoveries ranging from 91.43% to 96.07% and relative standard deviations lower than 4.34%. The detection limit of various furanocoumarins was found to be in the range of 0.37 mg mL-1 for xanthotoxol to 10.82 mg mL-1 for imperatorin. The results presented in the paper reveal that MSPD is efficient, fast, simple and easy to perform method suitable for the isolation of furanocoumarins from herbs.

Anna, Oniszczuk; Krystyna, Skalicka-Wo& #378; niak; Tomasz, Oniszczuk; Monika, Waksmundzka-Hajnos; Kaziemirz, G& #322; owniak.

1166-11-01

95

Molecularly imprinted polymer / cryogel composites for solid phase extraction of bisphenol A from river water and wine  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Superporous monolithic hydrogels (cryogel monoliths) are elastic, sponge-like materials that can be prepared in an aqueous medium through a cryotropic gelation technique. These monoliths show interesting properties for the development of high- throughput solid phase extraction supports to treat large volumes of aqueous samples. In this work, a cryogel-supported molecularly imprinted solid-phase extraction approach for the endocrine disruptor bisphenol A (BPA) from river water and wine samp...

Giraudi, Gianfranco; Anfossi, Laura; Baggiani, Claudio; Baravalle, Patrizia Domenica; Giovannoli, Cristina

2010-01-01

96

Molecularly imprinted solid-phase extraction for selective trace analysis of trifluoperazine.  

Science.gov (United States)

In this study, a novel sample clean-up technique based on the molecularly imprinted solid-phase extraction procedure is described for the determination of trifluoperazine (TFP) in biological fluids. The water-compatible molecularly imprinted polymers (MIPs) were prepared by using methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linker, chloroform as porogen and TFP as the template molecule. The novel imprinted polymer was used as a solid-phase extraction sorbent for the extraction of TFP from human serum and urine samples. Various parameters affecting the extraction efficiency of the polymer were evaluated. The selectivity of MIPs was evaluated by checking several substances with molecular structures similar to the template. The limits of detection and quantification for TFP in urine samples were 0.06 and 0.2 µg/L, respectively. These limits for TFP in serum samples were 0.15 and 0.4 µg/L, respectively. The recovery values for serum and urine samples were higher than 92 and 93%, respectively. PMID:23788020

Attaran, Abdol Mohammad; Mohammadi, Narges; Javanbakht, Mehran; Akbari-Adergani, Behrouz

2014-08-01

97

Determination of trace copper in food samples by flame atomic absorption spectrometry after solid phase extraction on modified soybean hull  

International Nuclear Information System (INIS)

Soybean hull was chemically modified with citric acid and used as a solid phase extraction adsorbent for the determination of trace amounts of Cu2+ in food samples by flame absorption spectrometry (FAAS). The effect of pH, sample flow rate and volume, elution flow rate and volume and co-existing ions on the recovery of the analyte were investigated. The results showed that Cu2+ could be adsorbed on the modified soybean hull at pH 8.0 and eluted by 2.0 mL of 1.0 mol L-1 HCl. Under the optimized conditions, the adsorption capacity of modified soybean hull was found to be 18.0 mg g-1 for Cu2+. The detection limit of the proposed method was 0.8 ng mL-1 for Cu2+ with an enrichment factor of 18. The analytical result for the certified reference tea sample (GBW07605) was in a good agreement with the certified value. The proposed method has also been successfully applied to the determination of trace Cu2+ in dried sweet potato, lake water and milk powder, the recovery of Cu2+ for spiked samples was between 91% and 109.6%.

98

Determination of trace copper in food samples by flame atomic absorption spectrometry after solid phase extraction on modified soybean hull  

Energy Technology Data Exchange (ETDEWEB)

Soybean hull was chemically modified with citric acid and used as a solid phase extraction adsorbent for the determination of trace amounts of Cu{sup 2+} in food samples by flame absorption spectrometry (FAAS). The effect of pH, sample flow rate and volume, elution flow rate and volume and co-existing ions on the recovery of the analyte were investigated. The results showed that Cu{sup 2+} could be adsorbed on the modified soybean hull at pH 8.0 and eluted by 2.0 mL of 1.0 mol L{sup -1} HCl. Under the optimized conditions, the adsorption capacity of modified soybean hull was found to be 18.0 mg g{sup -1} for Cu{sup 2+}. The detection limit of the proposed method was 0.8 ng mL{sup -1} for Cu{sup 2+} with an enrichment factor of 18. The analytical result for the certified reference tea sample (GBW07605) was in a good agreement with the certified value. The proposed method has also been successfully applied to the determination of trace Cu{sup 2+} in dried sweet potato, lake water and milk powder, the recovery of Cu{sup 2+} for spiked samples was between 91% and 109.6%.

Xiang Guoqiang, E-mail: xianggq@126.com [School of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou 450001 (China); Zhang Yingming; Jiang Xiuming; He Lijun; Fan Lu; Zhao Wenjie [School of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou 450001 (China)

2010-07-15

99

Separation and Purification of Sulforaphane from Broccoli by Solid Phase Extraction  

Directory of Open Access Journals (Sweden)

Full Text Available A simple solid-phase extraction (SPE method for the determination of sulforaphane in broccoli has been developed. The optimal conditions were found to be use of a silica SPE cartridge, and ethyl acetate and dichloromethane as washing and eluting solvents, respectively, which could eliminate interferences originating from the broccoli matrix. The extracts were sufficiently clean to be directly injected into high-performance liquid chromatography (HPLC for further chromatographic analysis. Good linearity was obtained from 0.05 to 200 ?g/mL (r = 0.998 for sulforaphane with the relative standard deviations less than 3.6%. The mean recoveries of sulforaphane from broccoli were more than 90.8% and the detection limit (S/N = 3:1 was 0.02 ?g/mL. The SPE method provides a higher yield of sulforaphane from crude extracts compared to conventional liquid-liquid extraction.

Kyung Ho Row

2011-03-01

100

Solid-phase extraction and HPLC determination of levamisole hydrochloride in sheep plasma  

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The anthelmintic, levamisole, was determined in sheep plasma by means of ion-pair solid-phase extraction (SPE) and reverse-phase liquid chromatography. The SPE columns were conditioned with 2 ml of methanol followed by 1 ml of octane sulphonic-acid buffer. After sample application, the columns were washed with 2 ml of the same buffer, followed by elution with 90/10 acetonitrile: buffer. A phenyl reversephase column (Spherisorb S5 Phenyl, 250 x 4,6 mm) was used with a mobile phase ...

Du Preez, J. L.; Lotter, A. P.

1996-01-01

 
 
 
 
101

Determination of amoxicillin in human plasma by high-performance liquid chromatography and solid phase extraction.  

Science.gov (United States)

A high-performance liquid chromatographic method using solid phase extraction has been developed for the determination of amoxicillin in human plasma. After concentration of amoxicillin on a C8 cartridge, the cartridge was eluted on-line to a reversed-phase column packed with 5 microns Chromspher C18. The mobile phase was methanol-0.08 M phosphate buffer (pH 7.6) (20:80), which contained 0.01 M tetrabutylammonium dihydrogenphosphate. The column effluent was monitored by UV spectrophotometry at 234 nm. The method has proved to be reliable and is used in bioavailability studies for the development of new amoxicillin formulations. PMID:8408402

Krauwinkel, W J; Volkers-Kamermans, N J; van Zijtveld, J

1993-08-11

102

VOLATILE COMPOUNDS OF LITHRAEA CAUSTICA (LITRE) DETERMINATED BY SOLID PHASE MICRO-EXTRACTION (SPME)  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in spanish De las partes áereas de Lithraea caustica y usando la técnica de Micro-Extracción en Fase Sólida (MEFS), fueron identificados y cuantificados los principales compuestos volátiles: los monoterpenos, mirceno, a -pineno, p-cimeno y limoneno, y el sesquiterpeno cariofileno. [...] Abstract in english The head space of the aerial parts of Lithraea caustica was analyzed by Solid Phase Micro-Extraction (SPME) technique, obtaining as main volatile compounds the monoterpenes, myrcene, a -pinene, , p-cymene and limonene, as well as the sesquiterpene caryophylene. [...

JUAN A, GARBARINO; GIUSEPPE, SALVATORE; MARISA, PIVANOVO; MARÍA CRISTINA, CHAMY; MARCELLO, NICOLETTI; ALFREDO, DE IOANNES.

103

Application of Reversed-Phase Solid Phase Extraction for the HPLC Analysis of Microcystins in Water  

Energy Technology Data Exchange (ETDEWEB)

To determine the concentrations of microcystins present in lake water or in tap water using high performance liquid chromatography, it is necessary to concentrate a large volume of water samples (about 20 L) into very small volume (0.1-0.3 mL). Concentration can be conveniently done when disc type solid phase extraction (SPE) apparatus is used. Using this apparatus we have investigated the recovery rates of three kinds of microcystins, RR, YR, LR, however, that the appropriate selection of the disc conditioning and eluting solvents and reproducible reconcentration process after SPE will improve both the recovery rates and the reproducibilities. (author). 19 refs., 3 tabs.

Kim, M.H. [Petroleum Quality Inspection Institute, Kyungki-do (Korea); Kim, T.S. [National Institute of Environmental Research, Seoul (Korea); Kim, T.K. [Chongju University, Chongju (Korea); Park, S.K. [National Institute of Environmental Research, Seoul (Korea)

2000-06-01

104

VOLATILE COMPOUNDS OF LITHRAEA CAUSTICA (LITRE DETERMINATED BY SOLID PHASE MICRO-EXTRACTION (SPME  

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Full Text Available The head space of the aerial parts of Lithraea caustica was analyzed by Solid Phase Micro-Extraction (SPME technique, obtaining as main volatile compounds the monoterpenes, myrcene, a -pinene, , p-cymene and limonene, as well as the sesquiterpene caryophylene.De las partes áereas de Lithraea caustica y usando la técnica de Micro-Extracción en Fase Sólida (MEFS, fueron identificados y cuantificados los principales compuestos volátiles: los monoterpenos, mirceno, a -pineno, p-cimeno y limoneno, y el sesquiterpeno cariofileno.

JUAN A GARBARINO

2002-12-01

105

Automated solid-phase extraction of herbicides from water for gas chromatographic-mass spectrometric analysis  

Science.gov (United States)

An automated solid-phase extraction (SPE) method was developed for the pre-concentration of chloroacetanilide and triazine herbicides, and two triazine metabolites from 100-ml water samples. Breakthrough experiments for the C18 SPE cartridge show that the two triazine metabolites are not fully retained and that increasing flow-rate decreases their retention. Standard curve r2 values of 0.998-1.000 for each compound were consistently obtained and a quantitation level of 0.05 ??g/l was achieved for each compound tested. More than 10,000 surface and ground water samples have been analyzed by this method.

Meyer, M.T.; Mills, M.S.; Thurman, E.M.

1993-01-01

106

Volatiles from Michelia champaca flower: comparative analysis by simultaneous distillation-extraction and solid phase microextraction.  

Science.gov (United States)

The chemical composition of the volatile compounds isolated by simultaneous distillation-extraction (SDE) and headspace-solid phase microextraction (SPME) from flowers of Michelia champaca growing in Cuba was investigated by GC/FID and GC/MS. Sixty-seven and thirty-four components were identified by SDE and SPME, respectively, with 1,8-cineole (22.8%) as the main constituent in the volatile oil isolated by SDE, and methyl benzoate (30.3%), indole (16.6%) and beta-elemene (10.4%) the major components detected by SPME. PMID:22799101

Báez, Disnelys; Morales, Diego; Pino, Jorge A

2012-05-01

107

Solid phase extraction and chromatographic determination of pesticide residues in water samples: DDT and its metabolites  

International Nuclear Information System (INIS)

Solid phase extraction cartridge embedded with octadecyl C/sub 18/ chain bounded to silica particles were used for the isolation and trace enrichment of pesticides from water samples collected from cotton, rice growing and municipal areas. The eluents were analyzed with HPLC using methanol (100%) as mobiles phase at different UV-Visible wavelengths. DDT and its metabolites were found in all areas but were not present in all samples. Concentration of pesticide residues varies from sample to sample and was in the range of 0.017 ng ml/sup -1/. Overall, recoveries ranged from 84%-91% for all target pesticides. (author)

108

VOLATILE COMPOUNDS OF LITHRAEA CAUSTICA (LITRE) DETERMINATED BY SOLID PHASE MICRO-EXTRACTION (SPME)  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in spanish De las partes áereas de Lithraea caustica y usando la técnica de Micro-Extracción en Fase Sólida (MEFS), fueron identificados y cuantificados los principales compuestos volátiles: los monoterpenos, mirceno, a -pineno, p-cimeno y limoneno, y el sesquiterpeno cariofileno. [...] Abstract in english The head space of the aerial parts of Lithraea caustica was analyzed by Solid Phase Micro-Extraction (SPME) technique, obtaining as main volatile compounds the monoterpenes, myrcene, a -pinene, , p-cymene and limonene, as well as the sesquiterpene caryophylene. [...

JUAN A, GARBARINO; GIUSEPPE, SALVATORE; MARISA, PIVANOVO; MARÍA CRISTINA, CHAMY; MARCELLO, NICOLETTI; ALFREDO, DE IOANNES.

2002-12-01

109

Characterisation of chamomile volatiles by simultaneous distillation solid-phase extraction in comparison to hydrodistillation and simultaneous distillation extraction.  

Science.gov (United States)

A new method for complete separation of steam-volatile organic compounds is described using the example of chamomile flowers. This method is based on the direct combination of hydrodistillation and solid-phase extraction in a circulation apparatus. In contrast to hydrodistillation and simultaneous distillation extraction (SDE), an RP-18 solid phase as adsorptive material is used rather than a water-insoluble solvent. Therefore, a prompt and complete fixation of all volatiles takes place, and the circulation of water-soluble bisabololoxides as well as water-soluble and thermolabile en-yne-spiroethers is inhibited. This so-called simultaneous distillation solid-phase extraction (SD-SPE) provides extracts that better characterise the real composition of the vapour phase, as well as the composition of inhalation vapours, than do SDE extracts or essential oils obtained by hydrodistillation. The data indicate that during inhalation therapy with chamomile, the bisabololoxides and spiroethers are more strongly involved in the inhaling activity than so far assumed. PMID:20033869

Krüger, Hans

2010-05-01

110

Development of andrographolide molecularly imprinted polymer for solid-phase extraction  

Science.gov (United States)

A method employing molecularly imprinted polymer (MIP) as selective sorbent for solid-phase extraction (SPE) to pretreat samples was developed. The polymers were prepared by precipitation polymerization with andrographolide as template molecule. The structure of MIP was characterized and its static adsorption capacity was measured by the Scatchard equation. In comparison with C 18-SPE and non-imprinted polymer (NIP) SPE column, MIP-SPE column displays high selectivity and good affinity for andrographolide and dehydroandrographolide for extract of herb Andrographis paniculata ( Burm.f.) Nees (APN). MIP-SPE column capacity was 11.9 ± 0.6 ?mol/g and 12.1 ± 0.5 ?mol/g for andrographolide and dehydroandrographolide, respectively and was 2-3 times higher than that of other two columns. The precision and accuracy of the method developed were satisfactory with recoveries between 96.4% and 103.8% (RSD 3.1-4.3%, n = 5) and 96.0% and 104.2% (RSD 2.9-3.7%, n = 5) for andrographolide and dehydroandrographolide, respectively. Various real samples were employed to confirm the feasibility of method. This developed method demonstrates the potential of molecularly imprinted solid phase extraction for rapid, selective, and effective sample pretreatment.

Yin, Xiaoying; Liu, Qingshan; Jiang, Yifan; Luo, Yongming

2011-06-01

111

Spectrophotometric determination of iron in environmental and food samples using solid phase extraction.  

Science.gov (United States)

A simple, selective and highly sensitive extraction method has been developed for the determination of iron(II) spectrophotometrically after solid phase extraction. The absorbance is measured at ?max 644 nm. Beer's law was obeyed up to 450 ng mL(-1) of iron. The molar absorptivity, Sandell's sensitivity, detection and quantification limits were calculated and found to be 1.09×10(5) L mol(-1) cm(-1), 0.51 ng cm(-2), 1.98 and 6.0 ng mL(-1), respectively and compared with parameters obtained without using solid phase extraction method. After reduction of Fe(III) by addition of 2.0 mL of 10% hydroxylamine HCl, the system was applied to the total iron. The interference of various ions has been studied in detail and the statistical evaluation of the experimental results is reported. The proposed methods have been successfully applied for the determination of trace amount of iron in environment water, soil and botanical reference materials with recovery range (98.71-101.51%). PMID:23870913

Kassem, Mohammed A; Amin, Alaa S

2013-12-01

112

A novel solid-phase extraction-spectrofluorimetric method for the direct determination of atenolol in human urine.  

Science.gov (United States)

A novel, simple, sensitive and selective solid-phase extraction (SPE)-spectrofluorimetric method has been developed for the determination of atenolol (ATE) in human urine. Because an extraction procedure is required to isolate ATE or eliminate the interfering molecules present in complex human urine for the direct spectrofluorimetric determination, a pH-sensitive poly(acrylic acid-ethylene glycol dimethacrylate) [poly(AA-EGDMA)] hydrogel was developed and used as a SPE adsorbent. Some factors affecting the ATE extraction efficiency, such as washing solvent type and volume, and the volume of elution solvent were optimized. Eluates from SPE cartridges were analyzed using a spectrofluorimeter (?(ex) ?=?277 nm and ?(em) ?=?300 nm). The calibration graph was linear over the concentration range 0.15-4.0 µg/mL. Limit of detection (LOD) and limit of quantification (LOQ) values were found to be 0.03 and 0.10 µg/mL, respectively. Relatively high intraday [2.06%, mean relative standard deviation (RSD)] and interday (2.6%, mean RSD) precisions were achieved. High mean recovery (95.4%) and low RSD values (3.8%) were obtained for spiked ATE in human urine. The spectrofluorimetric method presented here can be easily applied to assay trace amounts of ATE in pharmaceuticals and biological samples. PMID:23733327

Basan, Hasan; Yar?mkaya, Sezen

2014-05-01

113

Solid-phase extraction and GC-MS analysis of potentially genotoxic cleavage products of ?-carotene in primary cell cultures.  

Science.gov (United States)

A validated method for the simultaneous determination of prominent volatile cleavage products (CPs) of ?-carotene in cell culture media has been developed. Target CPs comprised ?-ionone (?-IO), cyclocitral (CC), dihydroactinidiolide (DHA), and 1,1,6-trimethyltetraline (TMT). CPs were extracted by solid-phase extraction applying a phenyl adsorbent, eluted with 10% (v/v) tetrahydrofuran in n-hexane, and identified and quantified by gas chromatography-mass spectrometry with electron impact ionization. Method validation addressed linearity confirmation over two application ranges and homoscedasticity testing. Recoveries from culture media were between 71.7% and 95.7% at 1.0 ?g/ml. Precision of recoveries determined in intra-day (N?=?5) and inter-day (N?=?15) assays were <2.0% and <4.8%, respectively. Limit of detection and limit of quantification of the analysis method were <18.0 and <53.0 ng/ml for ?-IO, CC, and TMT, whereas 156 and 474 ng/ml were determined for DHA, respectively. Although extractions of blank matrix proved the absence of interfering peaks, statistical comparison between slopes determined for instrumental and total method linearity revealed significant differences. The method was successfully applied in selecting an appropriate solvent for the fortification of culture media with volatile CPs, including the determination of their availability over the incubation period. For the first time, quantification of volatile CPs in treatment solutions and culture media for primary cells becomes accessible by this validated method. PMID:21400075

Martano, G; Vogl, C; Bojaxhi, E; Bresgen, N; Eckl, P; Stutz, H

2011-06-01

114

Matrix solid-phase dispersion extraction of organophosphorus pesticide using SiO2-poly(N-vinylimidazole)  

International Nuclear Information System (INIS)

A sorbent material based on silica particles modified with poly(N-vinylimidazole) (SiO2-PVI) has been evaluated for the treatment of samples by matrix solid-phase dispersion (MSPD). The extraction of four organophosphorus pesticides was done from a spiked tomato and the extracts were analyzed by gas chromatography coupled to mass spectrometry. Six elution solvents were evaluated and acetone was selected due to better recovery of the four pesticides and low background signal in the chromatograms. A factorial design 24 was used for selection of extraction conditions. The factors were contact time, acetone volume, treatment (with or without freeze-drying) and adsorbent (SiO2 or SiO2-PVI). The best recoveries were obtained using 15 minutes of contact, 2 mL of solvent and sorbent without freeze-drying. The recoveries were between 60 and 83% for SiO2-PVI in spiked tomato with 0.2 and 0.8?g/g.

115

Determination of five pyrethroids in tea drinks by dispersive solid phase extraction with polyaniline-coated magnetic particles.  

Science.gov (United States)

The polyaniline-coated magnetic particles with bowl-shaped morphology (Fe3O4/C/PANI microbowls) were successfully prepared and characterized by scanning electron microscopy, transmission electron microscopy and vibrating sample magnetometry. The prepared microbowls were used as the magnetic adsorbent in dispersive solid phase extraction of five pyrethroids, including cyhalothrin, beta-cypermethrin, esfenvalerate, permethrin and bifenthrin in plain tea drinks. The effects of experiment factors, including amount of Fe3O4/C/PANI microbowls, pH value, ultrasound extraction time and desorption conditions, were investigated. The extraction recoveries obtained with 8 mg of magnetic microbowls were satisfactory, and the microbowls can be reused after easy washing. Thus, a simple, selective and effective method for the determination of the pyrethroids was established successfully. The results showed that the method had good linearity (r=0.9992-0.9998), and the limits of detections (LODs) were from 0.025 to 0.032 ng mL(-1). The intra-day and inter-day relative standard deviations (RSDs) were in the range of 2.4-6.1% and 3.5-8.8%, respectively. Recoveries obtained by analyzing the real tea drinks were in the range of 72.1-118.4%. PMID:24401414

Wang, Yuanpeng; Sun, Ying; Gao, Yan; Xu, Bo; Wu, Qiong; Zhang, Hanqi; Song, Daqian

2014-02-01

116

Comparison of solvent extraction and solid-phase extraction for the determination of polychlorinated biphenyls in transformer oil.  

Science.gov (United States)

Solid-phase extraction (SPE) of nine polychlorinated biphenyls (PCBs) from transformer oil samples was evaluated using octadecyl (CI8)-bonded porous silica. The efficiency of SPE of these PCBs was compared with those obtained by solvent extraction with DMSO and hexane. Average recoveries exceeding 95% for these PCBs were obtained via the SPE method using small cartridges containing 100mg of 40 pm CI8-bonded porous silica. The average recovery by solvent extraction with DMSO and hexane exceeded 83%. It was concluded that the recoveries and precision for the solvent extraction of PCBs were poorer than those for the SPE. PMID:24083901

Mahindrakar, A N; Chandra, S; Shinde, L P

2014-01-01

117

An interior needle electropolymerized pyrrole-based coating for headspace solid-phase dynamic extraction  

International Nuclear Information System (INIS)

A headspace solid-phase dynamic extraction (HS-SPDE) technique was developed by the use of polypyrrole (PPy) sorbent, electropolymerized inside the surface of a needle, as a possible alternative to solid-phase microextraction (SPME). Thermal desorption was subsequently, employed to transfer the extracted analytes into the injection port of a gas chromatography-mass spectrometry (GC-MS). The PPy sorbent including polypyrrole-dodecyl sulfate (PPy-DS) was deposited on the interior surface of a stainless steel needle from the corresponding aqueous electrolyte by applying a constant deposition potential. The homogeneity and the porous surface structure of the coating were examined using the scanning electron microscopy (SEM). The developed method was applied to the trace level extraction of some polycyclic aromatic hydrocarbons (PAHs) from aqueous sample. In order to enhance the extraction efficiency and increase the partition coefficient of analytes, the stainless steel needle was cooled at 5 deg. C, while the sample solution was kept at 80 deg. C. Optimization of influential experimental conditions including the voltage of power supply, the time of PPy electrodeposition, the extraction temperature, the ionic strength and the extraction time were also investigated. The detection limits of the method under optimized conditions were in the range of 0.002-0.01 ng mL-1. The relative standard deviations (R.S.D.) at a concentration level of 0.1 ng mL-1 werration level of 0.1 ng mL-1 were obtained between 7.54 and 11.4% (n = 6). The calibration curves of PAHs showed linearity in the range of 0.01-10 ng mL-1. The proposed method was successfully applied to the extraction of some selected PAHs from real-life water samples and the relative recoveries were higher than 90% for all the analytes

118

Rapid determination of ions by combined solid-phase extraction--diffuse reflectance spectroscopy  

Science.gov (United States)

We introduce colorimetric solid-phase extraction (C-SPE) for the rapid determination of selected ions. This new technique links the exhaustive concentration of an analyte by SPE onto a membrane disk surface for quantitative measurement with a hand-held diffuse reflectance spectrometer. The concentration/measurement procedure is complete in approximately 1 min and can be performed almost anywhere. This method has been used to monitor iodine and iodide in spacecraft water in the 0.1-5.0 ppm range and silver(I) in the range of 5.0-1000 microg/l. Applications to the trace analysis of copper(II), nickel(II), iron(III) and chromium(VI) are described. Studies on the mechanism of extraction showed that impregnation of the disk with a surfactant as well as a complexing reagent results in uptake of additional water, which markedly improves the extraction efficiency.

Fritz, James S.; Arena, Matteo P.; Steiner, Steven A.; Porter, Marc D.

2003-01-01

119

Determination of available phenolic compounds in soils by liquid chromatography with solid-phase extraction.  

Science.gov (United States)

A fast, selective, and sensitive liquid chromatographic (LC) method was developed for determination of derivatives of benzoic and cinnamic acids (gallic, protocatechuic, 2,3,4-trihydroxybenzoic, 4-hydroxybenzoic, vanillic, caffeic, syringic, 4-coumaric, ferulic, sinapic, benzoic, 2-coumaric, cinnamic acids, and 4-hydroxybenzaldehyde and vanillin) in soil samples. The method for sample pretreatment is based on temperature-controlled extraction with water (pH 5.6) for 60 min. Extracts were preconcentrated and purified by solid-phase extraction on OASIS HLB sorbent, with subsequent separation and quantification of individual substances by LC with UV diode-array detection. Limits of detection (3 signal-to-noise LODs) better than 65 ng/g (dry weight) and recoveries from 88 to 99% were found for each compound at absorbance 280 nm. The method was used for determination of bioavailable phenolic compounds in different soil samples. PMID:12477182

Matejícek, David; Klejdus, Borivoj; Kubán, Vlastimil

2002-01-01

120

[Determination of histamine in fish and fish products by tandem solid-phase extraction].  

Science.gov (United States)

A simple and practical method was developed for the determination of histamine in fish and fish products by solid-phase extraction and fluorescence derivatization. Histamine was extracted with trichloroacetic acid. The extract was neutralized and diluted with phosphate buffer (pH 6.8), and cleaned up with a tandem-connected octadecyl silica (ODS) and strong cation exchange silica (SCX) cartridge. After removal of the solvent, histamine was derivatized with fluorescamine and analyzed by ion-paired reversed-phase high-performance liquid chromatography with fluorescence detection. Recovery tests of histamine from six kinds of fish and fish products showed acceptable recovery (83-92%) with low relative standard deviation (less than 5%). This method could be useful for determination of histamine in fish. PMID:21720127

Awazu, Kaoru; Nomura, Chie; Yamaguchi, Mizuka; Obana, Hirotaka

2011-01-01

 
 
 
 
121

Optimization of Solid Phase Micro-Extraction (SPME for Monitoring Occupational Exposure to Ethyl Benzene  

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Full Text Available AbstractBackground and Objectives: Analytical methods for volatile organic compounds (VOCs in different samples need extraction of compounds, by applying hazardous solvents. Solid phase micro-extraction (SPME is a solvent-free equilibrium extraction method, in which proper calibration can allow quantitative determinations of VOCs at a very good sensitivity without the use of any organic solvent. VOCs are generally present in urine only at trace levels, therefore, a sensitive procedure is needed for their trace determinations. Throughout this study, headspace solid phase micro-extraction (HS-SPME was followed by GC-FID for ethyl benzene in spiked urine was optimized.Methods: In this study, the parameters influencing SPME and gas chromatography of ethyl benzene, including extraction time, temperature, desorption temperature, desorption time, salt addition, sample pH, sample volume and sample agitation were investigated. Results: Extraction procedure was performed at 30°C for 6 min, using 0.2 gml-1 of NaCl in the sample solution. The sample volume and sample pH were optimized at 5 ml and 7 (neutral pH, respectively. Desorption of the ethyl benzene was carried out for 60 sec. at 250°C. The method was also validated with three different spiked urine samples and illustrated an appropriate reproducibility over six consecutive days as well as six within-day experiments. During this investigation, parameters of accuracy, linearity, and detection limits of the procedure were also evaluated.Conclusion: The developed method of HS- SPME-GC-FID proved to be a simple, convenient, and practical procedure, and was successfully used for measuring of ethyl benzene in spiked urine.

H. Heidari

2009-08-01

122

Selective enrichment of the degradation products of organophosphorus nerve agents by zirconia based solid-phase extraction.  

Science.gov (United States)

Selective extraction and enrichment of nerve agent degradation products has been achieved using zirconia based commercial solid-phase extraction cartridges. Target analytes were O-alkyl alkylphosphonic acids and alkylphosphonic acids, the environmental markers of nerve agents such as sarin, soman and VX. Critical extraction parameters such as modifier concentration, nature and volume of washing and eluting solvents were investigated. Amongst other anionic compounds, selectivity in extraction was observed for organophosphorus compounds. Recoveries of analytes were determined by GC-MS which ranged from 80% to 115%. Comparison of zirconia based solid-phase extraction method with anion-exchange solid-phase extraction revealed its selectivity towards phosphonic acids. The limits of detection (LOD) and limit of quantification (LOQ) with selected analytes were achieved down to 4.3 and 8.5 ng mL(-1), respectively, in selected ion monitoring mode. PMID:21862029

Kanaujia, Pankaj K; Pardasani, Deepak; Tak, Vijay; Purohit, Ajay K; Dubey, D K

2011-09-23

123

Solid phase extraction and spectrophotometric determination of palladium with 2-(2-quinolylazo-5-diethylaminobenzoic acid  

Directory of Open Access Journals (Sweden)

Full Text Available Asensitive, selective and rapid method for the determination of palladium based on the rapid reaction of palladium(II with 2-(2-quinolylazo-5-diethylaminobenzoic acid (QADEAB and the solid phase extraction of the Pd(II –QADEAB chelate with a reversed phase polymer-based C18 cartridge was developed. In the presence of 0.05 – 0. 5 mol/L of hydrochloric acid solution and cetyl trimethylammonium bromide (CTAB medium, QADEAB reacts with palladium(II to form a violet complex with a mole ratio 1:2 (palladium to QADEAB. The chelate was enriched by solid phase extraction with a reversed phase polymer-based C18 cartridge. An enrichment factor of 200 was obtained by elution of the chelate form the cartridge with the minimal amount of isopentyl alcohol. The molar absorptivity of the chelate in the isopentyl alcohol medium was 1.43 × 105 L mol-1 cm-1 at 628 nm. Beer’s law was obeyed in the range of 0.01 – 1.2 mg/mL. The relative standard deviation for eleven replicate samples at the 0.2 mg/L level was 2.18 %. The attained detection limit amounted to 0.02 mg/L in the original samples. This method was applied to the determination of palladium in environmental samples with good results.

WEIZU YANG

2006-07-01

124

Monitoring of chloropesticide methoxychlor preconcentration from waste water using hplc - solid phase extraction (abstract)  

International Nuclear Information System (INIS)

The method involves preconcentration of methoxychlor by solid phase extraction (SPE) with 1 mL silica based C-18 and 3 mL polymer based C-18 cartridge and then quantification by high performance liquid chromatography with UV detector (HPLC-UV). Optimization of HPLC parameters was done by determining max of methoxychlor on a double beam UV/Visible spectrophotometer, flow rate of mobile phase on reversed phase columns. Lowest detection limit for methoxychlor dissolved in water and methanol was 0.2ppm and 0.1ppm respectively. For solid phase extraction recovery studies and effect of different parameters such as initial concentration of analyte 0.01 to 0.05 ppm, loading rate 1 and 2mL/min, nature of desorbing solvent (methanol, ethyl acetate and acetonitrile) were investigated. Periodic self degradation of methoxychlor, and reusing potential of both SPE materials was also explored. Lower initial concentrations and slower loading rate of methoxychlor solutions gave improved recoveries. Recoveries were in the range of 80 to 90% for new SPE cartridge and reduced to 35 to 57% for once used silica based C-18 tubes. It was around 73 % for HLB C18 on their second use, and decreased on their repeated reuse. Lastly recoveries for stimulant and real waste water samples were determined to be 77 and 60% respectively. (author)

125

Solid phase extraction and spectrophotometric determination of trace amounts of thiocyanate in real samples.  

Science.gov (United States)

A simple, selective and rapid method for solid phase extraction and spectrophotometric determination of thiocyanate using a manganese (III) tetrakis (p-sulfonatophenyl) porphyrin, [Mn (TPPS) OAC] bound to Amberlite IR-400 has been developed. The influence of pH, amount of solid phase, sample matrix, type and amount of eluting agent and flow rates i.e. variables affecting the efficiency of the extraction system were evaluated and conditions of the sample, eluting solution and active phase were optimized. The maximal capacity was found to be as 1.16 microg mL(-1) for 1200 mL. Thiocyanate ions can be eluted quantitatively with 8 mL 0.3 M ferric chloride. The enrichment factor was 150. The linear range of the determination is between 0.4-2.0 microg mL(-1) for preconcentration method with a limit of detection of 2.8 ng mL(-1). The method has been successfully applied for determination of trace amounts of thiocyanate in tap water, saliva sample and a synthetic mixture. PMID:17217173

Ghaedi, Mehrorang; Parham, Hooshang; Moghadam, Majid; Mortazavi, Kianosh; Soylak, Mustafa

2006-01-01

126

Novel polymeric resin for solid phase extraction and determination of lead in waters  

Energy Technology Data Exchange (ETDEWEB)

Interest in preconcentration techniques for the determination of metals at ultratrace levels still continues increasingly because of some disadvantages of flameless atomic absorption spectrometry and the high costs of other sensitive methods in compared to flame atomic absorption spectrometry (FAAS). Among preconcentration techniques, solid-phase extraction is the most popular because of a number of advantages. In this work, thiol-containing sulfonamide resin was synthesized, characterized, and applied as a new sorption material for solid phase extraction and determination of lead in natural water samples. The optimization of experimental conditions was performed using the parameters including pH, contact time, and volumes of initial and elution solutions. After preconcentration procedure, FAAS was used for determinations. The synthesized resin exhibits the superiority in compared to the other adsorption reagents because of the fact that there is no necessity of any complexing reagent as well as high sorption capacity. Consequently, 280-fold improvement in the sensitivity of analytical scheme was achieved by combining the slotted tube atom trap-atomic absorption spectrometry (STAT-FAAS) and the developed preconcentration method. The limit of detection was found to be 0.15 ng mL{sup -1}. The Pb{sup 2+} concentrations in the studied water samples were found to be in the range of 0.9-6.7 ng mL{sup -1}. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Karaaslan, Nagihan M.; Cengiz, Emine; Yaman, Mehmet [Science Faculty, Department of Chemistry, Firat University, Elazig (Turkey); Senkal, B. Filiz [Science and Arts Faculty, Department of Chemistry, Istanbul Technical University, Istanbul (Turkey)

2010-11-15

127

Hemimicelle capped functionalized carbon nanotubes-based nanosized solid-phase extraction of arsenic from environmental water samples  

International Nuclear Information System (INIS)

The end functionalization of CNTs can introduce oxygen-containing negatively functional groups such as -COOH, -OH, or -C=O on their surface site. If cationic surfactant such as cetyltrimethylammonium chloride (CTAC) was added to the functionalized CNTs, then interactions such as hydrophobic and ionic may lead to formation of hemimicelle/admicelle aggregates on the CNTs, a new kind of adsorbents, namely, the hemimicelle capped CMMWCNTs, is obtained. The application of the hemimicelle capped carbon nanotubes-based nanosized solid-phase extraction (SPE) adsorbents in environmental analysis is reported for the first time using arsenic as model target. The effect of adsorption and desorption conditions for arsenic including the amount of surfactant, initial pH of sample solution, the ultrasonic time of sample solution, the amount of electrolyte, flow rate, eluent and its amount were investigated and optimized prior to its determination by atomic fluorescence spectrophotometry (AFS). Arsenic can be quantitatively retained on the hemimicelle capped CMMWCNTs at pH 5-6 from sample volume up to 500 mL and then eluted completely with 2 mol L-1 HNO3 in the presence of 10 mg L-1 CTAC. The method detection limit for arsenic determination with AFS detection was 2 ng L-1, and the relative standard deviation (RSD, n = 11) was 5.3% at the 0.5 ?g L-1 level. The recoveries of arsenic in the spiked environmental water samples ranged from 94% to 104.29% with 500 mL of water sample. The proposed method has been applied successfully to the analysis of arsenic in aqueous environmental samples, which demonstrates the hemimicelle capped CMMWCNTs can be an excellent SPE adsorbents for arsenic pretreatment and enrichment from real water samples

128

Evaluation of single-walled carbon nanohorns as sorbent in dispersive micro solid-phase extraction  

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer The potential of single walled carbon nanohorns in dispersive solid phase microextraction has been evaluated. Black-Right-Pointing-Pointer The method was characterized for the extraction of PAHs from waters. Black-Right-Pointing-Pointer Single walled carbon nanohorns were better extractant than carbon nanotubes and carbon nanocones. Black-Right-Pointing-Pointer The limits of detection were adequate for the target analytes in environmental waters. - Abstract: A new dispersive micro solid-phase extraction method which uses single-walled carbon nanohorns (SWNHs) as sorbent is proposed. The procedure combines the excellent sorbent properties of the nanoparticles with the efficiency of the dispersion of the material in the sample matrix. Under these conditions, the interaction with the analytes is maximized. The determination of polycyclic aromatic hydrocarbons was selected as model analytical problem. Two dispersion strategies were evaluated, being the functionalization via microwave irradiation better than the use of a surfactant. The extraction was accomplished by adding 1 mL of oxidized SWHNs (o-SWNHs) dispersion to 10 mL of water sample. After extraction, the mixture was passed through a disposable Nylon filter were the nanoparticles enriched with the PAHs were retained. The elution was carried out with 100 {mu}L of hexane. The limits of detection achieved were between 30 and 60 ng L{sup -1} with a precision (as repeatability) better than 12.5%. The recoveries obtained for the analytes in three different water samples were acceptable in all instances. The performance of o-SWNHs was favourably compared with that provided by carboxylated single-walled carbon nanotubes and thermally treated carbon nanocones.

Jimenez-Soto, Juan Manuel; Cardenas, Soledad [Department of Analytical Chemistry, Institute of Fine Chemistry and Nanochemistry, Marie Curie Building, Campus de Rabanales, University of Cordoba, 14071 Cordoba (Spain); Valcarcel, Miguel, E-mail: qa1meobj@uco.es [Department of Analytical Chemistry, Institute of Fine Chemistry and Nanochemistry, Marie Curie Building, Campus de Rabanales, University of Cordoba, 14071 Cordoba (Spain)

2012-02-10

129

Evaluation of single-walled carbon nanohorns as sorbent in dispersive micro solid-phase extraction  

International Nuclear Information System (INIS)

Highlights: ? The potential of single walled carbon nanohorns in dispersive solid phase microextraction has been evaluated. ? The method was characterized for the extraction of PAHs from waters. ? Single walled carbon nanohorns were better extractant than carbon nanotubes and carbon nanocones. ? The limits of detection were adequate for the target analytes in environmental waters. - Abstract: A new dispersive micro solid-phase extraction method which uses single-walled carbon nanohorns (SWNHs) as sorbent is proposed. The procedure combines the excellent sorbent properties of the nanoparticles with the efficiency of the dispersion of the material in the sample matrix. Under these conditions, the interaction with the analytes is maximized. The determination of polycyclic aromatic hydrocarbons was selected as model analytical problem. Two dispersion strategies were evaluated, being the functionalization via microwave irradiation better than the use of a surfactant. The extraction was accomplished by adding 1 mL of oxidized SWHNs (o-SWNHs) dispersion to 10 mL of water sample. After extraction, the mixture was passed through a disposable Nylon filter were the nanoparticles enriched with the PAHs were retained. The elution was carried out with 100 ?L of hexane. The limits of detection achieved were between 30 and 60 ng L?1 with a precision (as repeatability) better than 12.5%. The recoveries obtained for the analytes in three different water samples wehree different water samples were acceptable in all instances. The performance of o-SWNHs was favourably compared with that provided by carboxylated single-walled carbon nanotubes and thermally treated carbon nanocones.

130

Determination of naphthenic acids in crude oils using nonaqueous ion exchange solid-phase extraction.  

Science.gov (United States)

A method is presented for the routine, rapid, and quantitative analysis of aliphatic and naphthenic acids in crude oils, based on their isolation using nonaqueous ion exchange solid-phase extraction cartridges. The isolated acid fractions are methylated and analyzed by gas chromatography and gas chromatography/mass spectrometry. The method is effective on both light and heavy oils and is capable of providing mechanistic information of geochemical significance on the origin of the acids in the oils. Analysis of oils that were solvent extracted from laboratory and field mesocosm marine sediment oil degradation studies indicate that this new method of analyzing the products of hydrocarbon biodegradation may be a useful tool for monitoring the progress of bioremediation of oil spills in the environment. PMID:11217788

Jones, D M; Watson, J S; Meredith, W; Chen, M; Bennett, B

2001-02-01

131

Analysis of volatiles of malt whisky by solid-phase microextraction and stir bar sorptive extraction.  

Science.gov (United States)

Blended Scotch whisky was analysed by solid-phase microextraction (SPME) and stir bar sorptive extraction (SBSE) to study the composition of the volatiles. For SPME analysis, three different fibres were compared, poly(dimethylsiloxane) (PDMS) (100 microm). poly(acrylate) (PA) (85 microm) and divinylbenzene-Carboxen on poly(dimethylsiloxane) (DVB-CAR-(PDMS) (50/30 microm). It was found that the PDMS and DVB-CAR-PDMS fibres showed a higher enrichment capacity than PA as well as a better reproducibility. The influence of sampling time, temperature and salt addition on the enrichment of volatiles as well as the difference between liquid and headspace SPME were studied. An optimum SPME method was developed. Finally a more recent sample preparation technique, namely SBSE was evaluated to extract whisky volatiles. PMID:12580490

Demyttenaere, Jan C R; Martínez, Jorge I Sánchez; Verhé, Roland; Sandra, Pat; De Kimpe, Norbert

2003-01-24

132

Solid phase extraction of 22 drugs of interest in the forensic toxicology field  

Directory of Open Access Journals (Sweden)

Full Text Available Many solid phase extraction columns which are dedicated to the extraction of various drugs associated with their specific protocols are proposed to the analyst. We have optimised a one stage procedure for the extraction from whole blood of acidic, neutral and basic drugs. Each step of the protocol has been optimised so as to obtain the best extraction recovery. The analysis of the extracts (identification and quantification has been realised with the help of High Performance Liquid Chromatography system coupled with a Diode Array Detector (HPLC-DAD. The SPE Evolute ABN column (Acid Base Neutral by Argonaut is the column which does extract the more and the best the different analysed components among all the columns which have been tested. Oasis HLB column (Hydrophilic Lipophilic Balance by Waters also allows the extraction of the whole list of active principles studied but with lower recoveries. The other columns studied (sold by Varian and Phenomenex presented insufficient results for this project. In the last step of the work we checked if the results did fit to the forensic toxicology purpose; detection and quantification limits have been compared to therapeutic and toxic concentrations usually found in forensic toxicology. Implementing this new procedure allowed us to create a method of comprehensive screening of drugs frequently implicated in forensic toxicology.

Mélinda Mancebo

2008-01-01

133

Principles and applications of colorimetric solid-phase extraction with negligible depletion  

Energy Technology Data Exchange (ETDEWEB)

Colorimetric solid-phase extraction (C-SPE) is an integrated technique in which an analyte is selectively concentrated onto a disk and then quantitated by diffuse reflectance spectroscopy. This paper describes the results of an investigation that applies the concept of negligible depletion (ND) to C-SPE, representing the first application of ND concepts to solid-phase extractions. The approach relies on passing the minimal volume of sample through the disk required to reach an equilibrium in which the concentration of analyte in the sample entering and exiting the disk are equal. At this point, the amount of analyte extracted by the disk is proportional to the sample concentration but is independent of the sample volume passed through the disk. With this new method, called C-SPE/ND, the precise measurement of sample volume is no longer necessary. The work herein details the general principles of this new methodology, and validates its basic tenets in an investigation of the extraction of the organic dye methyl violet. The analytical capabilities of C-SPE/ND are then demonstrated by its application to measurements of iodine. Iodine is a biocide increasingly used as a simple and effective disinfectant for water in locations where municipal water treatment systems are potentially compromised. Thus, the ability to operate C-SPE in an ND mode notably enhances the broad-based utility of this methodology as a reliable and an easy-to-use analysis tool for water quality assessments. Since iodine is also the biocide used on NASAs Space Shuttle, C-SPE/ND has the potential to overcome problems associated with the removal of air bubbles entrapped in a water sample in the microgravity environment encountered in space exploration. Extensions of C-SPE/ND to facile determinations of other water quality parameters with respect to both earth- and space-based needs are briefly discussed.

Dias, Neil C. [Institute for Combinatorial Discovery, Ames Laboratory-U.S. Department of Energy, Department of Chemistry, Iowa State University, Ames, IA 50011 (United States); Porter, Marc D. [Institute for Combinatorial Discovery, Ames Laboratory-U.S. Department of Energy, Department of Chemistry, Iowa State University, Ames, IA 50011 (United States)]. E-mail: mporter@porter1.ameslab.gov; Fritz, James S. [Institute for Combinatorial Discovery, Ames Laboratory-U.S. Department of Energy, Department of Chemistry, Iowa State University, Ames, IA 50011 (United States)

2006-02-03

134

Extraction of pesticides from plants using solid phase microextraction and QuEChERS  

Scientific Electronic Library Online (English)

Full Text Available SciELO South Africa | Language: English Abstract in english A study employing dispersive solid phase extraction in the form of the quick, easy, cheap, effective, rugged and safe (QuEChERS) method and solid phase microextraction (SPME) for the cleanup of pesticides in plant samples from the Okavango Delta (Botswana) is presented. Concentration levels of aldri [...] n, 1,1-dichloro-2,4-bis[chlorophenyl]ethane (DDD), 1,1-dichloro-2,2-bis[p-chlorophenyl]ethylene(DDE), 1,1,1-trichloro-2,2-bis[p-chlorophenyl]ethane (DDT), dieldrin, endosulfan and endrin were investigated using gas chromatography with electron capture detection (GC-ECD) and confirmed with gas chromatography with high resolution time of flight mass spectrometry (GC-TOFMS). Parameters affecting the extraction efficiencies of both techniques were optimized. In the absence of CRMs for the plants under investigation, method validation and evaluation of the extraction efficiencies were achieved through spiking of Nymphaea nouchali (Tswii) leaves at two concentration levels with trichlorobenzene as an internal standard. Recoveries for both SPME and QuEChERS were in the range 61-95 %. The calibration plots were reproducible and linear (R² > 0.995) with limits of detection ranging from 0.102 to 1.693 µg L-1 for all the pesticides. The optimal conditions for QuEChERS and SPME were applied to the extraction of pesticides residues from the edible parts (leaves, roots and/ or stems) of Asparagus africanus, Cleome hirta and Nymphaea nouchali plants. No pesticides were detected in the leaves and stems of all the plants studied. Aldrin and endosulfan were detected in the Nymphaea nouchali roots at concentrations of 3-21 µg kg-1 and 5-3 µg kg-1, respectively. Pentachlorobenzene (PCB) and hexachlorobenzene (HCB) were also detected but were not quantified.

Veronica C., Obuseng; Beauty M., Mookantsa; Harriet, Okatch; Ketlhatlogile, Mosepele; Nelson, Torto.

135

Combined liquid and solid-phase extraction improves quantification of brain estrogen content  

Directory of Open Access Journals (Sweden)

Full Text Available Accuracy in quantifying brain-derived steroid hormones (‘neurosteroids’ has become increasingly important for understanding the modulation of neuronal activity, development, and physiology. Relative to other neuroactive compounds and classical neurotransmitters, steroids pose particular challenges with regard to isolation and analysis, owing to their lipid solubility. Consequently, anatomical studies of the distribution of neurosteroids have relied primarily on the expression of neurosteroid synthesis enzymes. To evaluate the distribution of synthesis enzymes vis-à-vis the actual steroids themselves, traditional steroid quantification assays, including radioimmunoassays (RIA, have successfully employed liquid extraction methods (e.g., ether, dichloromethane or methanol to isolate steroids from microdissected brain tissue. Due to their sensitivity, safety and reliability, the use of commercial enzyme immunoassays (EIA for laboratory quantification of steroids in plasma and brain has become increasingly widespread. However, EIAs rely on enzymatic reactions in vitro, making them sensitive to interfering substances in brain tissue and thus producing unreliable results. Here, we evaluate the effectiveness of a protocol for combined, two-stage liquid/solid phase extraction as compared to conventional liquid extraction alone for the isolation of estradiol (E2 from brain tissue. We employ the songbird model system, in which brain steroid production is pronounced and linked to neural mechanisms of learning and plasticity. This study outlines a combined liquid-solid phase extraction protocol that improves the performance of a commercial EIA for the quantification of brain E2 content. We demonstrate the effectiveness of our optimized method for evaluating the region specificity of brain E2 content, compare these results to established anatomy of the estrogen synthesis enzyme and estrogen receptor, and discuss the nature of potential EIA interfering substances.

LukeRemage-Healey

2011-09-01

136

Extraction of pesticides from plants using solid phase microextraction and QuEChERS  

Scientific Electronic Library Online (English)

Full Text Available SciELO South Africa | Language: English Abstract in english A study employing dispersive solid phase extraction in the form of the quick, easy, cheap, effective, rugged and safe (QuEChERS) method and solid phase microextraction (SPME) for the cleanup of pesticides in plant samples from the Okavango Delta (Botswana) is presented. Concentration levels of aldri [...] n, 1,1-dichloro-2,4-bis[chlorophenyl]ethane (DDD), 1,1-dichloro-2,2-bis[p-chlorophenyl]ethylene(DDE), 1,1,1-trichloro-2,2-bis[p-chlorophenyl]ethane (DDT), dieldrin, endosulfan and endrin were investigated using gas chromatography with electron capture detection (GC-ECD) and confirmed with gas chromatography with high resolution time of flight mass spectrometry (GC-TOFMS). Parameters affecting the extraction efficiencies of both techniques were optimized. In the absence of CRMs for the plants under investigation, method validation and evaluation of the extraction efficiencies were achieved through spiking of Nymphaea nouchali (Tswii) leaves at two concentration levels with trichlorobenzene as an internal standard. Recoveries for both SPME and QuEChERS were in the range 61-95 %. The calibration plots were reproducible and linear (R² > 0.995) with limits of detection ranging from 0.102 to 1.693 µg L-1 for all the pesticides. The optimal conditions for QuEChERS and SPME were applied to the extraction of pesticides residues from the edible parts (leaves, roots and/ or stems) of Asparagus africanus, Cleome hirta and Nymphaea nouchali plants. No pesticides were detected in the leaves and stems of all the plants studied. Aldrin and endosulfan were detected in the Nymphaea nouchali roots at concentrations of 3-21 µg kg-1 and 5-3 µg kg-1, respectively. Pentachlorobenzene (PCB) and hexachlorobenzene (HCB) were also detected but were not quantified.

Veronica C., Obuseng; Beauty M., Mookantsa; Harriet, Okatch; Ketlhatlogile, Mosepele; Nelson, Torto.

2013-08-01

137

Determination of quinolones in milk samples using a combination of magnetic solid-phase extraction and capillary electrophoresis.  

Science.gov (United States)

A magnetic solid-phase extraction (MSPE) method combined with capillary electrophoresis for the simultaneous determination of seven quinolones (QNs) (danofloxacin, ciprofloxacin, marbofloxacin, enrofloxacin, difloxacin, oxolinic acid, and flumequine), using (S)-(+)-6-methoxy-?-methyl-2-naphthaleneacetic acid as internal standard, in milk samples was developed. The variables involved in the preconcentration magnetic procedure were: the composition of the magnetic support composition, the sample pH, and the weight of magnetic adsorbent used. The variables were optimized using a simplex-lattice design. Different magnetite covered with octyl-phenyl silica adsorbents were synthesized by varying the molar ratio of phenyltrimethylsilane and octyltrimethoxysilane; the solids were evaluated for QN preconcentration. Under optimal conditions, a linear range was obtained from 27 to 1000 ?g L(-1) with limits of detection ranging from 9 to 12 ?g L(-1) for the seven QNs. The absolute recoveries of the seven QNs at three different spiked levels (40, 150, and 400 ?g L(-1) ) ranged from 74% to 98% with a relative standard deviation less than 10% in all cases. The proposed method was applied to analyze 20 whole milk samples of different brands. All samples were positive for the presence of QN residues; in some cases, extract dilution was required. The concentrations found are in the range from 31.1 to 5047.3 ?g L(-1) . Marbofloxacin was the most frequently found. The method proposed offers advantages in terms of simplicity, sensitivity, efficiency, cost, and analysis time making it an alternative for the analysis of QNs in whole milk samples. PMID:22806471

Ibarra, Israel S; Rodriguez, Jose A; Páez-Hernández, Ma Elena; Santos, Eva M; Miranda, Jose M

2012-07-01

138

Separation of lanthanum (3) and neodymium (3) by tributyl phosphate extraction in the presence of solid phase  

International Nuclear Information System (INIS)

Lanthanum (3) and neodymium (3) extraction from nitric acid solutions by tributyl phosphate in the presence of solid phase of the element nitrates is investigated. An increase in distribution of neodymium nitrate in the presence of solid phase with the decrease in its concentration in the initial solution and with the increase in lanthanum nitrate concentration is detected. The highest effect of extractive-crystallizational separation is observed in the range of neodymium nitrate microconcentrations. A method of neodymium quantitative extraction from lanthanum nitrate solutions with neodymium - lanthanum separation coefficient exceeding 25 is suggested

139

Ionic liquid-modified materials for solid-phase extraction and separation: a review.  

Science.gov (United States)

In recent years, materials science has propelled to the research forefront. Ionic liquids with unique and fascinating properties have also left their footprints to the developments of materials science during the last years. In this review we highlight some of their recent advances and provide an overview at the current status of ionic liquid-modified materials applied in solid-phase extraction, liquid and gas chromatography and capillary electrochromatography with reference to recent applications. In addition, the potential of ionic liquids in the modification of capillary inner wall in capillary electrophoresis is demonstrated. The main target material modified with ionic liquids is silica, but polymers and monoliths have recently joined the studies. Although imidazolium is still clearly the most commonly used ionic liquid for the covalently modification of materials, the exploitation of pyridinium and phosphonium will most probably increase in the future. PMID:22244164

Vidal, Lorena; Riekkola, Marja-Liisa; Canals, Antonio

2012-02-17

140

Solid Phase Extraction (SPE) of REE's and uranium using sequestered resin  

International Nuclear Information System (INIS)

A novel resin has been designed and developed for the pre-concentration and separation of trace amounts of rare earth elements (REE's) from uranium containing aqueous effluent by solid phase extraction technique. Determinations of Gadolinium (Gd) and Uranium (U) have been carried out by ICP-AES. Experiments were carried out using both batch and column techniques. Parameters such as equilibration rate, effect of concentration on sorption and desorption of metal ions have been studied. The maximum separation factor capacities for Gd and U were found to be 0.98 at pH 1.5 for Gd and same for U at pH 1.00 respectively when contacted originally 20 ppm Gadolinium and 10 ppm Uranium containing simulated solution. The designed sequestered resin was reusable even after 10 cycles

 
 
 
 
141

Solid phase extraction for sample preparation in trace analysis of ionogenic compounds by capillary isotachophoresis  

International Nuclear Information System (INIS)

Various sorbents recommended for solid phase extraction (SPE) in sample preparation procedures were studied for use in combination with capillary isotachophoresis (ITP). They were very efficient in achieving trace concentration levels (low ppb, i.e., low parts per 109) for different types of ITP analytes present in environmental and biological matrices. A macroporous carbon sorbent was convenient for sample preparation in ITP analysis of short chain fatty acids (C4-C9) in drinking water. Chelating sorbents based on hydroxyalkyl methacrylate matrix with salicylate, thioglycolate and 8-hydroxyquinolinate functionalities were found to be very suitable for preconcentration of heavy metals with an inherent sample clean-up. An octadecyl-bonded silica sorbent enabled in ITP a photometric detection of ?-aminobutyrate (labeled with a 2,4,6-trinitrophenyl group) at concentrations considerably lower than required for the determination of this amino acid in cerebrospinal fluid (?5*10-8 mol/l). (author) 34 refs.; 3 figs.; 1 tab

142

High-performance liquid chromatographic assay of dilazep in plasma after solid-phase extraction.  

Science.gov (United States)

A new, simple and accurate high-performance liquid chromatography method is presented for measuring dilazep in plasma, using a reversed-phase technique and UV absorption at 267 nm. Dilazep and papaverine (the internal standard) added to plasma were successfully isolated using a solid-phase extraction procedure (CN cartridges). The method was linear between 2.5-12.5 micrograms ml-1. Over the tested concentration range the intra-day coefficient of variation for replicate analyses of plasma ranged from 2.38 to 5.27% (the day-to-day CV ranged from 2.52 to 7.99%). The detection limit for the analysis of dilazep in plasma was 50 ng with 20 microliters injection. PMID:9160267

Gumieniczek, A; Przyborowski, L

1997-04-01

143

A solid phase extraction procedure for Indium prior to its graphite furnace atomic absorption spectrometric determination  

International Nuclear Information System (INIS)

A procedure based on solid phase extraction of indium ions at trace level on Chromosorb 108 resin as bathocuproinedisulfonic acid chelate is presented for its preconcentration. The optimum pH value for quantitative sorption is 8.0-9.0, and desorption can be achieved by using 10.0 ml of 2 M HNO3. The effects of diverse ions on the sorption and recovery of indium have been studied. The capacity of sorbent was 3.78 mg In/g resin. Recoveries for indium from water samples were in the range 95-105%. The accuracy of procedure was confirmed by indium determination in certified reference materials. The method developed was applied with varying results to the analysis of real samples including metallic zinc with satisfactory results

144

Analysis of imazaquin in soybeans by solid-phase extraction and high-performance liquid chromatography.  

Science.gov (United States)

An analytical method for the determination imazaquin residues in soybeans was developed. The developed liquid/liquid partition and strong anion exchange solid-phase extraction procedures provide the effective cleanup, removing the greatest number of sample matrix interferences. By optimizing mobile-phase pH water/acetonitrile conditions with phosphoric acid, using a C-18 reverse-phase chromatographic column and employing ultraviolet detection, excellent peak resolution was achieved. The combined cleanup and chromatographic method steps reported herein were sensitive and reliable for determining the imazaquin residues in soybean samples. This method is characterized by recovery >88.4%, precision Imazaquin residues in soybeans were further confirmed by high performance liquid chromatography-mass spectrometry (LC-MS). The proposed method was successfully applied to the analysis of imazaquin residues in soybean samples grown in an experimental field after treatments of imazaquin formulation. PMID:18183337

Guo, C; Hu, J-Y; Chen, X-Y; Li, J-Z

2008-02-01

145

Determination of Nickel in Water and Wastewater at Ultratrace Level by Solid-Phase Extraction-Flame Atomic Absorption Spectrometry  

International Nuclear Information System (INIS)

Solid-phase extraction using octadecyl silica membrane disk modified with 2[(2-mercaptophenylimino)methyl] phenol (MPMP) ligand was utilized in FAAS determination of ultratrace amount of nickel in water and wastewater samples. Ni2+ ions were adsorbed quantitatively during the passage of an aqueous sample through the modified octadecyl silica membrane disk. The retained Ni2+ ions were then eluted from the disk with 5 mL of 0.5 mol L-1 nitric acid as an eluent, and subsequently determined by FAAS. The break-through volume of the method was 2000 mL, which corresponded to the enrichment factor of 400. Maximum capacity of the membrane disk modified with 6 mg of the ligand was 210 ?g of Ni2+, and the limit of determination was 0.17 ?g L-1. The effect of various ionic interferences on preconcentration and determination of nickel in binary mixture was studied. The method was successfully applied to determination of nickel in water and wastewater samples; accuracy was examined in recovery experiment and by independent GFAAS analysis (graphite furnace atomic absorption spectrometry). The accuracy was further confirmed by applying the proposed method to the analysis of standard reference alloy (BCR No 112) and comparing the result with the declared value. (authors)

146

Selective solid-phase extraction of Sudan I in chilli sauce by single-hole hollow molecularly imprinted polymers.  

Science.gov (United States)

A new single-hole hollow molecularly imprinted polymer (SHH-MIP) was prepared by multistep seed swelling polymerization using Sudan I as template molecule and successfully applied to selective solid-phase extraction (SPE) of Sudan dyes in chilli sauce samples. The polymers possessed high specific surface area obtained by nitrogen adsorption and good thermal stability without decomposition lower than 380 °C by thermogravimetry analysis. Much higher binding capacity was exhibited than with irregular solid MIP prepared by bulk polymerization, because most of the binding sites were located in the surface of the polymers, facilitating template removal and mass transfer. Accordingly, the SHH-MIP was employed as SPE adsorbent for chilli sauce analysis and offered high recoveries for Sudan I in the range of 87.5-103.4% with the precision of 1.94-5.33% at three spiked levels. The SHH-MIP with high selectivity and high stability was demonstrated to be potentially applicable for high selective preconcentration and determination of trace Sudan dyes in complicated samples. PMID:22168281

Zhang, Zhong; Xu, Shoufang; Li, Jinhua; Xiong, Hua; Peng, Hailong; Chen, Lingxin

2012-01-11

147

Determination of volatile organic hydrocarbons in water samples by solid-phase dynamic extraction  

Energy Technology Data Exchange (ETDEWEB)

In the present study a headspace solid-phase dynamic extraction method coupled to gas chromatography-mass spectrometry (HS-SPDE-GC/MS) for the trace determination of volatile halogenated hydrocarbons and benzene from groundwater samples was developed and evaluated. As target compounds, benzene as well as 11 chlorinated and brominated hydrocarbons (vinyl chloride, dichloromethane, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, carbon tetrachloride, chloroform, trichloroethylene, tetrachloroethylene, bromoform) of environmental and toxicological concern were included in this study. The analytes were extracted using a SPDE needle device, coated with a poly(dimethylsiloxane) with 10% embedded activated carbon phase (50-{mu}m film thickness and 56-mm film length) and were analyzed by GC/MS in full-scan mode. Parameters that affect the extraction yield such as extraction and desorption temperature, salting-out, extraction and desorption flow rate, extraction volume and desorption volume, the number of extraction cycles, and the pre-desorption time have been evaluated and optimized. The linearity of the HS-SPDE-GC/MS method was established over several orders of magnitude. Method detection limits (MDLs) for the compounds investigated ranged between 12 ng/L for cis-dichloroethylene and trans-dichloroethylene and 870 ng/L for vinyl chloride. The method was thoroughly validated, and the precision at two concentration levels (0.1 mg/L and a concentration 5 times above the MDL) was between 3.1 and 16% for the analytes investigated. SPDE provides high sensitivity, short sample preparation and extraction times and a high sample throughput because of full automation. Finally, the applicability to real environmental samples is shown exemplarily for various groundwater samples from a former waste-oil recycling facility. Groundwater from the site showed a complex contamination with chlorinated volatile organic compounds and aromatic hydrocarbons. (orig.)

Jochmann, Maik A.; Schmidt, Torsten C. [Eberhard-Karls-Universitaet Tuebingen, Center for Applied Geoscience (ZAG), Tuebingen (Germany); Chair of Instrumental Analysis, University Duisburg-Essen, Duisburg (Germany); Yuan, Xue [Eberhard-Karls-Universitaet Tuebingen, Center for Applied Geoscience (ZAG), Tuebingen (Germany)

2007-03-15

148

Solid phase microextraction and stir bar sorptive extraction for organotin compounds - a comparison (P9)  

International Nuclear Information System (INIS)

Full text: Organotin compounds have been largely used in agricultural and industrial applications. Hyphenated techniques were developed for the sensitive and selective determination of such species. For this task GC has been coupled with atomic emission detection. Derivatization to transform the Sn-compounds into sufficiently volatile compounds was necessary and carried out using sodium tetrapropylborate. For sample preparation the application of solid phase microextraction (SPME) give recent advances in comparison to classical liquid-liquid extraction (LEE). A problem in the usage of SPME exists however in the small volume of the PDMS coating for enrichment the analytes. For improvement of both sample enrichment and extraction of the organotin compounds stir bar sorptive extraction (SBSE) was applied. It base on the application of stir bars coated with PDMS. Here the extraction yield is substantially higher. Aim of this study was to compare the capabilities of GC-AED in combination with SPME and SBSE. After optimization of the experimental parameters it was possible to reach detection limits in the pg / 1 - level. A comparison of both methods shows the expected results. By application of SBSE it was possible to increase the detection limits one order of magnitude. With SPME the reproducibility of the analytical results (in the 1 ng / 1 concentration range) was found to be between 10 and 15 %, it could be enhanced to 5-8 % by application of SBSE. These low limits of detection and the good reproducibility allowed the determination of organotin compounds according required regulations. Ref. 1 (author)

149

A rapid solid-phase extraction fluorometric method for thiamine and riboflavin in salmonid eggs  

Science.gov (United States)

A new method has been developed and successfully applied to the selective measurement of thiamine (nonphosphorylated), total thiamine (sum of thiamine, thiamine monophosphate [TMP], thiamine diphosphate [TDP], and thiamine triphosphate [TTP]), and potentially interfering riboflavin in acidic (2% trichloroacetic acid) extracts of selected salmonid and walleye egg samples. Acidic extracts of eggs were applied directly to end-capped C18, reversed-phase solid-phase extraction (SPE) columns and separated into three fractions by elution with mixtures of PO4 buffer (pH 2), methanol (10%), and acetonitrile (20%). All thiamine compounds recovered in the first two fractions were oxidized to their corresponding thiochromes with alkaline potassium hexacyanoferrate, and we measured the thiochrome fluorescence (excitation at 360 nm, emission at 460 nm) in a 96-well microplate reader. Riboflavin, recovered in third fraction (eluted with pH 2, 20% acetonitrile), was analyzed directly by measuring the fluorescence of this fraction (excitation at 450 nm, emission at 530 nm). Significant portions of the phosphate esters of thiamine (TMP, TDP, and presumably TTP), when present at low concentrations (extract thiamine compounds into 2% trichlororacetic acid solution; an inexpensive, commercially available SPE column; small amounts of sample (0.5-1 g); microliter volumes of solvents per sample; a traditional, relatively nonhazardous, oxidation of thiamine compounds to fluorescent thiochromes; and an ultraviolet-visible-wavelength-filter fluorometer for the measurements. ?? Copyright by the American Fisheries Society 2005.

Zajicek, J.L.; Tillitt, D.E.; Brown, S.B.; Brown, L.R.; Honeyfield, D.C.; Fitzsimons, J.D.

2005-01-01

150

Volatile composition of peppermint (Mentha piperita L.) commercial teas through solid phase extraction.  

Science.gov (United States)

Volatiles from aqueous extract of peppermint commercial sachets were investigated through gas chromatography/flame ionization detection (GC/FID) and GC/mass spectrometry (MS). Samples were prepared under similar conditions as in homemade tea. Volatiles were isolated using solid phase extraction method (SPE) with Porapak Q trap followed by desorption with acetone. Estimated mean values for short and medium chain carboxylic acids (C2-C12) and ketones lay in the range of 50-64 microg kg(-1) whilst aliphatic alcohols and acyclic hydrocarbons had values lower than 6 microg kg(-1). The major volatiles were terpenes (275-382 microg kg(-1)) that reached 89 % of the total composition. A total of 16 compounds, among them dodecane, acetoin, acetol, citral, geraniol and octanoic acid have been described by the first time in peppermint tea. These findings could be attributed to the different analytical approach employed, mainly to the use of different extraction/pre-concentration techniques. Given the apparently lower proportion of terpenes in the aqueous extract it may be that the chemical properties of the peppermint essential oil are not entirely reproduced with homemade tea. PMID:24020260

Riachi, L G; Abi-Zaid, I E; Moreira, R F A; De Maria, C A B

2012-12-01

151

Bioactive phenols in algae: the application of pressurized-liquid and solid-phase extraction techniques.  

Science.gov (United States)

A new extraction technique based on the off-line combination of pressurized-liquid with solid-phase extraction (PLE-SPE) is described. The method was used for the extraction of bioactive phenolic acids (protocatechuic, p-hydroxybenzoic, 2,3-dihydroxybenzoic, chlorogenic, vanillic, caffeic, p-coumaric, salicylic acid), cinnamic acid and hydroxybenzaldehydes (p-hydroxybenzaldehyde, 3,4-dihydroxybenzaldehyde, vanillin) from in vitro culture of two freshwater algae (Anabaena doliolum and Spongiochloris spongiosa) and from food products of marine macroalgae Porphyra tenera (nori) and Undaria pinnatifida (wakame). For the identification and quantification of the compounds the molecular ions [M-H](-) and specific fragments were analyzed by quadrupole mass spectrometry analyzer connected on-line with a reversed-phase HPLC system. Our analysis showed that the freshwater algae and marine algal products contained submicrogram or microgram level of above-mentioned phenols per gram of lyophilized sample. In addition, the total phenol content (Folin-Ciocalteu assay) and antioxidant activity (TEAC assay, Trolox equivalent antioxidant capacity assay) of the PLE-SPE extracts were determined and discussed. PMID:19410410

Onofrejová, L; Vasícková, J; Klejdus, B; Stratil, P; Misurcová, L; Krácmar, S; Kopecký, J; Vacek, J

2010-01-20

152

Insight into the extraction mechanism of polymeric ionic liquid sorbent coatings in solid-phase microextraction.  

Science.gov (United States)

An investigation into the mechanism of extraction for polymeric ionic liquid (PIL)-based solid phase microextraction sorbent coatings is described. Four PIL-based coatings, namely, a poly(1-4-vinylbenzyl)-3-hexadecylimidazolium bis[(trifluoromethyl)sulfonyl] imide (poly([VBHDIM][NTf2])) PIL produced through 2,2'-azo-bis(isobutyronitrile) (AIBN) initiated free-radical polymerization, a UV-initiated poly(1-vinyl-3-hexylimidazolium) chloride (poly([VHIM][Cl])) PIL, and two crosslinked PILs containing the same IL monomers copolymerized with dicationic IL crosslinkers, were investigated. Calibration curves of 1-octanol were plotted in the presence of naphthalene, a model interfering compound, to observe changes in the linear range, sensitivity, and amount of analytes extracted. Results were compared with a polydimethylsiloxane/divinylbenzene (PDMS/DVB) coating and a polyacrylate (PA) coating which are known to extract analytes primarily through adsorption and partitioning mechanisms, respectively. All PIL-based coatings extracted analytes via a non-competitive partitioning mechanism regardless of the extent of crosslinking. PMID:23746645

Ho, Tien D; Cole, William T S; Augusto, Fabio; Anderson, Jared L

2013-07-12

153

Carbon nanotubes as solid-phase extraction sorbents prior to atomic spectrometric determination of metal species: A review  

International Nuclear Information System (INIS)

Highlights: ? The use of CNTs as sorbent for metal species in solid phase extraction has been described. ? Physical and chemical strategies for functionalization of carbon nanotubes have been discussed. ? Published analytical methods concerning solid phase extraction and atomic spectrometric determination have been reviewed. - Abstract: New materials have significant impact on the development of new methods and instrumentation for chemical analysis. From the discovery of carbon nanotubes in 1991, single and multi-walled carbon nanotubes – due to their high adsorption and desorption capacities – have been employed as sorption substrates in solid-phase extraction for the preconcentration of metal species from diverse matrices. Looking for successive improvements in sensitivity and selectivity, in the past few years, carbon nanotubes have been utilized as sorbents for solid phase extraction in three different ways: like as-grown, oxidized and functionalized nanotubes. In the present paper, an overview of the recent trends in the use of carbon nanotubes for solid phase extraction of metal species in environmental, biological and food samples is presented. The determination procedures involved the adsorption of metals on the nanotube surface, their quantitative desorption and subsequent measurement by means of atomic spectrometric techniques such as flame atomic absorption spectrometry, electrothermal atomic absorption spectrometry or inductively coupled plasma a or inductively coupled plasma atomic emission spectrometry/mass spectrometry, among others. Synthesis, purification and types of carbon nanotubes, as well as the diverse chemical and physical strategies for their functionalization are described. Based on 140 references, the performance and general properties of the applications of solid phase extraction based on carbon nanotubes for metal species atomic spectrometric determination are discussed.

154

Selective solid-phase extraction using molecularly imprinted polymer for analysis of methamidophos in water and soil samples.  

Science.gov (United States)

An analytical methodology for the analysis of methamidophos in water and soil samples incorporating a molecularly imprinted solid-phase extraction process using methamidophos-imprinted polymer was developed. Binding study demonstrated that the polymer exhibited excellent affinity and high selectivity to the methamidophos. Evidence was also found by FT-IR analysis that hydrogen bonding between the CO(2)H in the polymer cavities and the NH(2) and P=O of the template was the origin of methamidophos recognition. The use of molecularly imprinted solid-phase extraction improved the accuracy and precision of the GC method and lowered the limit of detection. The recovery of methamidophos extracted from a 10.0 g soil sample at the 100 ng/g spike level was 95.4%. The limit of detection was 3.8 ng/g. The recovery of methamidophos extracted from 100 mL tap and river water at 1 ng/mL spike level was 96.1% and 95.8%, and the limits of detection were 10 and 13 ng/L respectively. These molecularly imprinted solid-phase extraction procedures enabled selective extraction of polar methamidophos successfully from water and soil samples, demonstrating the potential of molecularly imprinted solid-phase extraction for rapid, selective, and cost-effective sample pretreatment. PMID:21389628

Shen, Zhong-Lan; Yuan, Dong; Su, Qing-De; Zhang, Hui; Wang, Jun; Zhu, Jian-Hua; Liu, Yan-Ming

2011-01-01

155

Determining plasma morphine levels using GC-MS after solid phase extraction to monitor drug levels in the postoperative period  

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OBJECTIVE: To implement a selective and sensitive analytical method to quantify morphine in small volumes of plasma by gas-liquid chromatography-mass spectrometry (GC-MS), aimed at post-operatively monitoring the drug. METHOD: A gas-liquid chromatographic method with mass detection has been developed to determine morphine concentration in plasma after solid phase extraction. Morphine-d3 was used as an internal standard. Only 0.5 mL of plasma is required for the drug solid-phase extraction in ...

Veronica Santos; Karin Jannet Vera López; Luciana Moraes Santos; Mauricio Yonamine; Maria José Carvalho Carmona; Silvia Regina Cavani Jorge Santos

2008-01-01

156

Sodium dodecyl sulfate coated ?-alumina support modified by a new Schiff base for solid phase extraction and flame-AAS determination of lead and copper ions  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english A simple and fast approach for solid phase extraction is herein described, and used to determine trace amounts of Pb2+ and Cu2+ metal ions. The solid phase support is sodium dodecyl sulfate (SDS)-coated ?-alumina modified with bis(2-hydroxy acetophenone)-1,6-hexanediimine (BHAH) ligand. The adsorbed [...] ions were stripped from the solid phase by 6 mL of 4 M nitric acid as eluent. The eluting solution was analyzed by flame atomic absorption spectrometry (FAAS). The sorption recovery of metal ions was investigated with regard to the effects of pH, amount of ligand, ?-alumina and surfactant and the amount and type of eluent. Complexation of BHAH with Pb2+ or Cu2+ ions was examined via spectrophotometry using the HypSpec program. The detection limit for Cu2+ was 7.9 µg L-1 with a relative standard deviation of 1.67%, while that for Pb2+ was 6.4 µg L-1 with a relative standard deviation of 1.64%. A preconcentration factor of 100 was achieved for these ions. The method was successfully applied to determine analyte concentrations in samples of liver, parsley, cabbage, and water.

Ardeshir, Shokrollahi; Morteza, Montazerozohori; Tahere, Mehrpour; Hossein, Tavallali; Batool Zare, Khafri; Zohreh, Montaseri.

157

Sodium dodecyl sulfate coated ?-alumina support modified by a new Schiff base for solid phase extraction and flame-AAS determination of lead and copper ions  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english A simple and fast approach for solid phase extraction is herein described, and used to determine trace amounts of Pb2+ and Cu2+ metal ions. The solid phase support is sodium dodecyl sulfate (SDS)-coated ?-alumina modified with bis(2-hydroxy acetophenone)-1,6-hexanediimine (BHAH) ligand. The adsorbed [...] ions were stripped from the solid phase by 6 mL of 4 M nitric acid as eluent. The eluting solution was analyzed by flame atomic absorption spectrometry (FAAS). The sorption recovery of metal ions was investigated with regard to the effects of pH, amount of ligand, ?-alumina and surfactant and the amount and type of eluent. Complexation of BHAH with Pb2+ or Cu2+ ions was examined via spectrophotometry using the HypSpec program. The detection limit for Cu2+ was 7.9 µg L-1 with a relative standard deviation of 1.67%, while that for Pb2+ was 6.4 µg L-1 with a relative standard deviation of 1.64%. A preconcentration factor of 100 was achieved for these ions. The method was successfully applied to determine analyte concentrations in samples of liver, parsley, cabbage, and water.

Ardeshir, Shokrollahi; Morteza, Montazerozohori; Tahere, Mehrpour; Hossein, Tavallali; Batool Zare, Khafri; Zohreh, Montaseri.

1354-13-01

158

Molecularly imprinted solid-phase extraction of matrine from radix Sophorae tonkinensis.  

Science.gov (United States)

In the study, molecularly imprinted polymers (MIPs) with special molecular recognition properties of matrine (MAT) were prepared in our lab, using melamine-urea-formaldehyde (MUF) as the functional monomer and matrine as the template. An equilibrium binding experiment was performed to investigate the binding ability of the MIPs, and indicated that the MIPs had a high adsorption and good elution ability to the target molecule MAT, when the template/functional monomer ratio (T/M) was 5 mg g(-1). Scatchard analysis and isothermal equilibrium adsorption indicated that only one kind of binding site had existed in the MAT-imprinted polymers with its dissociation constants estimated to be 3.31 × 10(-4) mol L(-1) (200-400 mesh (inch(-1))) and 6.83 × 10(-4) mol L(-1) (over 400 mesh (inch(-1))) depending on the mesh of the MIPs. MAT purification and elution experiments were carried out using MIPs as the solid-phase extraction (MISPE) sorbent, and acetone, water, and chloroform as the elution solvents. The results demonstrated that MIPs achieved their highest adsorption capability after treatment with alkaline solution, while acetone was the most efficient elution solvent. Then, a crude extraction of matrine in radix Sophorae tonkinensis was performed using these MIPs as the separation medium. The results showed that MIPs had a high MAT selectivity, and the amount of matrine content obtained by MISPE was 1.4-fold to that obtained by liquid-liquid extraction. PMID:21655631

Guo, Zhifeng; Zhang, Lixia; Song, Caiyu; Zhang, Xiaoxuan

2011-07-21

159

Application of solid phase micro extraction (SPME) in profiling hydrocarbons in oil spill cases  

International Nuclear Information System (INIS)

In environmental forensic, it is extremely important to have a fast and reliable method in identifying sources of spilled oil and petroleum products. In this study, solid phase micro extraction (SPME) method coupled to gas chromatography-mass spectrometry was developed for the analysis of hydrocarbons in diesel and petroleum contaminated soil samples. Optimization of SPME parameters such as extraction time, extraction temperature and desorption time, was performed using 100-?m poly dimethylsiloxane (PDMS) fiber. These parameters were studied at three levels by means of a central composite experimental design and the optimum experimental conditions were determined using response surface method. The developed SPME method was applied to determine the profiles of hydrocarbons in several oil contaminated soil sample. The SPME method was also used to study the effects of weathering on the profiles of hydrocarbons in unleaded gasoline, diesel and kerosene contaminated soil samples. After several days, significant losses of the lighter hydrocarbons were observed compared to the heavier ones. From these data, SPME method can be used to differentiate possible candidate sources in oil spill cases. (author)

160

PHARMACOKINETIC STUDY OF RISPERIDONE: APPLICATION OF A HPLC METHOD WITH SOLID PHASE EXTRACTION  

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Full Text Available A new, simplified solid phase extraction procedure for the determination of risperidone and 9-hydroxyrisperidone in human plasma has been developed. This method involves the use of an optimized extraction protocol developed in Waters OASIS® HLB 30mg 1cc extraction columns using 1 mL of human serum. Separation was performed by HPLC using a Waters XTerra RP-18 (5 µm, 150x4,6 mm column with a mobile phase consisting in acetonitrile - potassium dihydrogen phosphate 50 mM pH 3.4 (27/73. UV detection at 278 nm was used to quantify analytes, encountering good linearity (r² > 0.999 in the 2-100 ng/mL concentration range. The mean recovery was 92.4 % and 92.8 % for risperidone and 9-hydroxyrisperidone respectively, with an intraday - interday precision below 7%, and accuracy below 115 %. The method has been successfully applied in pharmacokinetic studies that require a large sample number.

PABLO TORRES V

2011-01-01

 
 
 
 
161

Solid phase extraction of magnetic carbon doped Fe3O4 nanoparticles.  

Science.gov (United States)

Carbon decorated Fe3O4 nanoparticles (Fe3O4/C) are promising magnetic solid-phase extraction (MSPE) sorbents in environmental and biological analysis. Fe3O4/C based MSPE method shows advantages of easy operation, rapidness, high sensitivity, and environmental friendliness. In this paper, the MSPE mechanism of Fe3O4/C nanoparticles has been comprehensively investigated, for the first time, through the following three efforts: (1) the comparison of extraction efficiency for polycyclic aromatic hydrocarbons (PAHs) between the Fe3O4/C sorbents and activated carbon; (2) the chromatographic retention behaviors of hydrophobic and hydrophilic compounds on Fe3O4/C nanoparticles as stationary phase; (3) related MSPE experiments for several typical compounds such as pyrene, naphthalene, benzene, phenol, resorcinol, anisole and thioanisole. It can be concluded that there are hybrid hydrophobic interaction and hydrogen bonding interaction or dipole-dipole attraction between Fe3O4/C sorbents and analytes. It is the existence of carbon and oxygen-containing functional groups coated on the surface of Fe3O4/C nanoparticles that is responsible for the effective extraction process. PMID:24342532

Yang, Jing; Li, Jia-yuan; Qiao, Jun-qin; Lian, Hong-zhen; Chen, Hong-yuan

2014-01-17

162

PHARMACOKINETIC STUDY OF RISPERIDONE: APPLICATION OF A HPLC METHOD WITH SOLID PHASE EXTRACTION  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english A new, simplified solid phase extraction procedure for the determination of risperidone and 9-hydroxyrisperidone in human plasma has been developed. This method involves the use of an optimized extraction protocol developed in Waters OASIS® HLB 30mg 1cc extraction columns using 1 mL of human serum. [...] Separation was performed by HPLC using a Waters XTerra RP-18 (5 µm, 150x4,6 mm) column with a mobile phase consisting in acetonitrile - potassium dihydrogen phosphate 50 mM pH 3.4 (27/73). UV detection at 278 nm was used to quantify analytes, encountering good linearity (r² > 0.999) in the 2-100 ng/mL concentration range. The mean recovery was 92.4 % and 92.8 % for risperidone and 9-hydroxyrisperidone respectively, with an intraday - interday precision below 7%, and accuracy below 115 %. The method has been successfully applied in pharmacokinetic studies that require a large sample number.

PABLO, TORRES V; M. JACQUELINE, SEPÚLVEDA C; CARLOS, VON PLESSING R.

163

In-line pressurized-fluid extraction-solid-phase extraction for determining phenolic compounds in grapes.  

Science.gov (United States)

A new method of pressurized-fluid extraction coupled in-line with solid-phase extraction has been used for the extraction of phenolic compounds from grapes. The full extraction method is performed under an inert atmosphere. Five different solvents have been assayed using different extraction pressures and temperatures. Using two extraction stages with two different solvents, water and methanol, quantitative recovery for most of the assayed compounds has been found in the second extract. Only the most polar phenolic compound, gallic acid, was found distributed in both extracts. The application to real samples allows for a clean-up of the extracts. Cinnamic esters like caftaric acid, cis and trans-coutaric acids were found only in the methanolic extract. The reproducibility for the new method was measured using both an inert solid spiked with standards and grapes. Using between 202 and 424 microg of spiked standards, the resulting relative standard deviations were less than 5%, with the exception of gallic acid (RSD=13%). For grapes, the resulting RSD were 11% for trans-coutaric acid, 10% for caftaric acid and 6% for cis-coutaric acid. PMID:12236492

Palma, Miguel; Piñeiro, Zulema; Barroso, Carmelo G

2002-08-30

164

Determination of Scopolamine in Human Saliva Using Solid Phase Extraction and LC/MS/MS  

Science.gov (United States)

Purpose: Scopolamine is the preferred treatment for motion sickness during space flight because of its quick onset of action, short half-life and favorable side-effect profile. The dose administered depends on the mode of administration and usually ranges between 0.1 and 0.8 mg. Such small doses make it difficult to detect concentrations of scopolamine in biological fluids by using conventional HPLC methods. To measure scopolamine in saliva and thereby to evaluate the pharmacokinetics of scopolamine, we developed an LC/MS/MS method using off-line solid phase extraction. Method: Samples (0.5mL) were loaded onto Waters Oasis HLB co-polymer cartridges (10 mg, 1 mL) and eluted with 0.5 mL methanol without evaporation and reconstitution. HPLC separation of the eluted sample was performed using an Agilent Zorbax SB-CN column (50 x 2.1 mm) at a flow rate of 0.2 mL/min for 4 minutes. The mobile phase for separation was 90:10 (v/v) methanol: ammonium acetate (2 mM) in water, pH 5.0 +/- 0.1. Concentrations of scopolamine were determined using a Micromass Quattro Micro(TM) mass spectrometer with electrospray ionization (ESI). ESI mass spectra were acquired in positive ion mode with multiple reaction monitoring for the determination of scopolamine m/z = 304.2 yields 138.1 and internal standard (IS) hyoscyamine m/z = 290.2 yields 124.1. Results: The method is rapid, reproducible, specific and has the following parameters: scopolamine and the IS are eluted at 1.7 and 3.2 min respectively. The linear range is 50-5000 pg/mL for scopolamine in saliva with correlation coefficients > 0.99 with a CV samples with concentrations of 75, 300, 750 and 3000 pg/mL of scopolamine in human saliva. Conclusion: Solid phase extraction allows more rapid sample preparation and greater precision than liquid extraction. Furthermore, we increased the sensitivity and specificity by adjusting the LC mobile phase and using an MS/MS detector.

Wang, Zuwei; Vaksman, Zalman; Boyd, Jason; Putcha, Lakshmi

2007-01-01

165

Determination of Scopolamine in Human Saliva Using Solid Phase Extraction and LC/MS/MS  

Science.gov (United States)

Purpose: Scopolamine is the preferred treatment for motion sickness during space flight because of its quick onset of action, short half-life and favorable side-effect profile. The dose administered depends on the mode of administration and usually ranges between 0.1 and 0.8 mg. Such small doses make it difficult to detect concentrations of scopolamine in biological fluids by using conventional HPLC methods. To measure scopolamine in saliva and thereby to evaluate the pharmacokinetics of scopolamine, we developed an LC/MS/MS method using off-line solid phase extraction. Method: Samples (0.5mL) were loaded onto Waters Oasis HLB co-polymer cartridges (10 mg, 1 mL) and eluted with 0.5 mL methanol without evaporation and reconstitution. HPLC separation of the eluted sample was performed using an Agilent Zorbax SB-CN column (50 x 2.1 mm) at a flow rate of 0.2 mL/min for 4 minutes. The mobile phase for separation was 90:10 (v/v) methanol: ammonium acetate (2 mM) in water, pH 5.0 +/- 0.1. Concentrations of scopolamine were determined using a Micromass Quattro Micro(TM) mass spectrometer with electrospray ionization (ESI). ESI mass spectra were acquired in positive ion mode with multiple reaction monitoring for the determination of scopolamine m/z = 304.2 yields 138.1 and internal standard (IS) hyoscyamine m/z = 290.2 yields 124.1. Results: The method is rapid, reproducible, specific and has the following parameters: scopolamine and the IS are eluted at 1.7 and 3.2 min respectively. The linear range is 50-5000 pg/mL for scopolamine in saliva with correlation coefficients > 0.99 with a CV Solid phase extraction allows more rapid sample preparation and greater precision than liquid extraction. Furthermore, we increased the sensitivity and specificity by adjusting the LC mobile phase and using an MS/MS detector.

Wang, Zuwei; Vaksman, Zalman; Boyd, Jason; Putcha, Lakshmi

2007-01-01

166

Determination of Scopolamine in Human Saliva Using Solid Phase Extraction and LC/MS/MS  

Science.gov (United States)

Purpose: Scopolamine is the preferred treatment for motion sickness during space flight because of its quick onset of action, short half-life and favorable side-effect profile. The dose administered depends on the mode of administration and usually ranges between 0.1 and 0.8 mg. Such small doses make it difficult to detect concentrations of scopolamine in biological fluids by using conventional HPLC methods. To measure scopolamine in saliva and thereby to evaluate the pharmacokinetics of scopolamine, we developed an LC/MS/MS method using off-line solid phase extraction. Method: Samples (0.5mL) were loaded onto Waters Oasis HLB co-polymer cartridges (10 mg, 1 mL) and eluted with 0.5 mL methanol without evaporation and reconstitution. HPLC separation of the eluted sample was performed using an Agilent Zorbax SB-CN column (50 x 2.1 mm) at a flow rate of 0.2 mL/min for 4 minutes. The mobile phase for separation was 90:10 (v/v) methanol: ammonium acetate (2 mM) in water, pH 5.0 +/- 0.1. Concentrations of scopolamine were determined using a Micromass Quattro Micro(TM) mass spectrometer with electrospray ionization (ESI). ESI mass spectra were acquired in positive ion mode with multiple reaction monitoring for the determination of scopolamine m/z = 304.2 yields 138.1 and internal standard (IS) hyoscyamine m/z = 290.2 yields 124.1. Results: The method is rapid, reproducible, specific and has the following parameters: scopolamine and the IS are eluted at 1.7 and 3.2 min respectively. The linear range is 50-5000 pg/mL for scopolamine in saliva with correlation coefficients > 0.99 with a CV < 0.5 %. The intra-day and inter-day CVs are < 15 % for quality control samples with concentrations of 75, 300, 750 and 3000 pg/mL of scopolamine in human saliva. Conclusion: Solid phase extraction allows more rapid sample preparation and greater precision than liquid extraction. Furthermore, we increased the sensitivity and specificity by adjusting the LC mobile phase and using an MS/MS detector.

Wang, Zuwei; Vaksman, Zalman; Boyd, Jason; Putcha, Lakshmi

2007-01-01

167

Utilization of Modified Corn Silk as a Biosorbent for Solid-phase Extraction of Cr(III) and Chromium Speciation.  

Science.gov (United States)

The ues of corn silk modified with diluted nitric acid (HNO3-MCS) as a novel biosorbent has been established for solid-phase extraction of Cr(III) and chromium speciation in water samples. The functional groups of the HNO3-MCS surface are favorable for the adsorption of Cr(III). Effective extraction conditions were optimized in both batch and column methods. At pH 3.0 - 6.0, a discrimination of Cr(III) and Cr(VI) is achieved on the HNO3-MCS surface. Cr(III) ions are retained onto the HNO3-MCS surface, however, the adsorption of Cr(VI) is negligible under the same conditions. The adsorption isotherm of HNO3-MCS for Cr(III) has been demonstrated in accordance with a linear form of the Langmuir equation, and the maximum adsorption capacity is 35.21 mg g(-1). The well fitted linear regression of the pseudo-second order model showed the indication of a chemisorption mechanism for the entire concentration range. Thermodynamic studies have shown that the adsorption process is spontaneous and endothermic. The adsorbed Cr(III) was quantitatively eluted by a nitric acid solution with detection by flame atomic absorption spectrometry (FAAS). With a sample volume of 30 mL, a detection limit (3?) of 0.85 ?g L(-1) and a precision of 2.0% RSD at the 40 ?g L(-1) level were achieved. The concentration of Cr(III) could be accurately quantified within a linear range of 3 - 200 ?g L(-1). After Cr(VI) has been reduced to Cr(III) with hydroxylamine hydrochloride, the total amount of chromium was obtained, and the content of Cr(VI) was given by subtraction. The procedure was validated by analyzing chromium in a certified reference material (GBW (E) 080039). It was also successfully applied for the speciation of chromium in wastewater samples. PMID:25382045

Yu, Hongmei; Pang, Jing; Wu, Mei; Wu, Qiaoli; Huo, Cuixiu

2014-01-01

168

Solid phase extraction and high performance liquid chromatographic determination of dobutamine in plasma of dialysed patients.  

Science.gov (United States)

An isocratic reversed-phase high performance liquid chromatographic method has been developed for th e determination of dobutamine in the plasma of dialysed patients. A solid phase extraction method with a Sep-Pak C18 cartridge was used to isolate the drug and isoxsuprine (internal standard) from plasma. The separation was carried out on an ODS-Hypersil column with 0.1 M phosphate buffer:acetonitrile:methanol (72:20:8 v/v/v) as the mobile phase. The recovery of dobutamine added to plasma by the extraction procedure was 87 +/- 2.3% (mean +/- SD). The accuracy and reproducibility of the method were within acceptable limits over the concentration range 0-1000 ng/mL. Quantification was by fluorescence detection at 275 nm excitation and 310 nm emission wavelengths with a detection limit of 5 ng/mL for dobutamine. This procedure was applied to ascertain the pharmacokinetics of dobutamine infusion in nine patients with cardiogenic shock and end-stage renal disease undergoing haemodialysis. PMID:7888736

Leflour, C; Dine, T; Luyckx, M; Brunet, C; Gressier, B; Cazin, M; Robert, H; Durocher, A; Cazin, J C

1994-01-01

169

Analysis of urinary benzodiazepines using solid-phase extraction and gas chromatography-mass spectrometry.  

Science.gov (United States)

A solid-phase extraction and GC-MS confirmation method was developed for certain urinary diazolo- and triazolobenzodiazepines, including the metabolites of lorazepam, clonazepam, alprazolam, and triazolam. The latter two do not form benzophenones, and the others are not readily confirmed by conventional thin-layer chromatography or GC-MS techniques. Samples were hydrolyzed with glucuronidase at 37 degrees C, adjusted to pH 4.5, extracted with Bond Elut Certify columns, dried, and derivatized using BSTFA with 1% TMCS. Sample preparation time averaged 4 hours. A GC-MS selected-ion-monitoring acquisition method targeting retention time, molecular ion abundances, and qualifier ion ratios was used to determine positive results. The recovery of 7-NH2-clonazepam was 95%, and recoveries of alpha-hydroxyalprazolam, alpha-hydroxytriazolam, and lorazepam were greater than 66%. Linearity was demonstrated from 0.1 to 1.0 microgram/mL for each drug. Within-run CVs were less than 11%, and between-run CVs were less than 16%. Using this technique, we have been able to confirm suspected cases of abuse that had not been confirmed by previous techniques. PMID:7967537

Black, D A; Clark, G D; Haver, V M; Garbin, J A; Saxon, A J

1994-01-01

170

Solid Phase Extraction for Monitoring of Occupational Exposure to Cr (III  

Directory of Open Access Journals (Sweden)

Full Text Available Chromium is an important constituent widely used in different industrial processes for production of various synthetic materials. For evaluation of workers’ exposure to trace toxic metal of Cr (III, environmental and biological monitoring are essential processes, in which, preparation of samples is one of the most time-consuming and error-prone aspects prior to analysis. The use of solid-phase extraction (SPE has grown and is a fertile technique of sample preparation as it provides better results than those produced by liquid-liquid extraction (LLE. SPE using mini columns filled with XAD-4 resin was optimized regarding to sample pH, ligand concentration, loading flow rate, elution solvent, sample volume, elution volume, amount of resins, and sample matrix interferences. Chromium was retained on solid sorbent and was eluted with 2 M HNO3 followed by simple determination of analytes by using flame atomic absorption spectrometery. Obtained recoveries of metal ion were more than 92%. The optimized procedure was also validated with three different pools of spiked urine samples and showed a good reproducibility over six consecutive days as well as six within-day experiments. Through this study, suitable results were obtained for relative standard deviation, therefore, it is concluded that, this optimized method can be considered to be successful in simplifying sample preparation for trace residue analysis of Cr in different matrices for evaluation of occupational and environmental exposures. To evaluate occupational exposure to chromium, 16 urine samples were taken, prepared, and analyzed based on optimized procedure.

S.J. Shahtaheri

2007-01-01

171

Solvent vapour monitoring in work space by solid phase micro extraction.  

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Solid phase micro extraction (SPME) is a fast, solvent-less alternative to conventional charcoal tube sampling/carbon disulfide extraction for volatile organic compounds (VOC). In this work, SPME was compared to the active sampling technique in a typical lab atmosphere. Two different types of fibre coatings were evaluated for solvent vapour at ambient concentration. A general purpose 100 microm film polydimethylsiloxane (PDMS) fibre was found to be unsuitable for VOC work, despite the thick coating. The mixed-phase carboxen/PDMS fibre was found to be suitable. Sensitivity of the SPME was far greater than charcoal sorbent tube method. Calibration studies using typical solvent such as dichloromethane (DCM), benzene (B) and toluene (T) showed an optimal exposure time of 5 min, with a repeatability of less than 20% for a broad spectrum of organic vapour. Minimum detectable amount for DCM is in the range of 0.01 microg/l (0.003 ppmv). Variation among different fibres was generally within 30% at a vapour concentration of 1 microg DCM/l, which was more than adequate for field monitoring purpose. Adsorption characteristics and calibration procedures were studied. An actual application of SPME was carried out to measure background level of solvent vapour at a bench where DCM was used extensively. Agreement between the SPME and the charcoal sampling method was generally within a factor of two. No DCM concentration was found to be above the regulatory limit of 50 ppmv. PMID:11267747

Li, K; Santilli, A; Goldthorp, M; Whiticar, S; Lambert, P; Fingas, M

2001-05-01

172

Determination of tetracycline residues by liquid chromatography coupled with electrochemical detection and solid phase extraction.  

Science.gov (United States)

A liquid chromatography based on the reverse phase separation and a solid phase extraction (SPE) procedure using a phenyl-silica sorbent for the simultaneous separation and extraction/preconcentration of six tetracyclines was studied and optimized. An amperometric detector using a polycrystalline gold electrode operating under both DC and IPAD conditions was tested for the determination of the selected tetracyclines. Under optimal SPE and chromatographic conditions, the limit of detection of the investigated tetracyclines comprised between 50 nM (25 microg L(-1)) and 75 nM (37 microg L(-1)), and the dynamic linear range spanned generally over 3 orders of magnitude, when the electrochemical detector was used under DC conditions at a constant applied potential of 1.6 V vs Ag/AgCl. The analytical method was successfully tested for the determination of tetracyclines in milk samples ((UHT low-fat, fresh pasteurized, and powdered milk) with reproducibility and recovery levels ranged between 3.1%-5.6% and 70%-118%, respectively. PMID:19754048

Casella, Innocenzo G; Picerno, Fabio

2009-10-14

173

Determination of glabridin in human plasma by solid-phase extraction and LC-MS/MS.  

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Glabridin is a major flavonoid included specifically in licorice (Glycyrrhiza glabra L.), and has various physiological activities including antioxidant and anti-inflammatory effects. We have developed and validated an analytical method for determination of glabridin in human plasma by solid-phase extraction (SPE) and LC-MS/MS. Glabridin was extracted from plasma by SPE using a C8 cartridge and analyzed by LC-MS/MS using mefenamic acid as an internal standard (IS). The analyte were separated by a C18 column on LC, and monitored with a fragment ion of m/z 201 formed from a molecular ion of m/z 323 for glabridin and that of m/z 196 from m/z 240 for IS during negative ion mode with tandem MS detection. The lower limit of quantitation (LLOQ) of glabridin was 0.1 ng/mL in plasma, corresponding to 1.25 pg injected on-column. The calibration curves exhibited excellent linearity (r>0.997) between 0.1 and 50 ng/mL. Precision and accuracy were 90%, and was stable when kept at 10 degrees C for 72 h, at -20 degrees C until 12 weeks, and after three freeze-thaw cycles. This is the first report on determination of glabridin in body fluids by the selective, sensitive, and reproducible method. PMID:16183339

Aoki, Fumiki; Nakagawa, Kaku; Tanaka, Akiyoshi; Matsuzaki, Kazue; Arai, Naoki; Mae, Tatsumasa

2005-12-15

174

Preconcentration of trace uranium from natural water with solid-phase extraction  

International Nuclear Information System (INIS)

In the present study, an effective method was used for the preconcentration and determination of uranium(VI) by solid-phase extraction (SPE). For this purpose, a microcolumn of alumina modified with sodium dodecyl sulfate (SDS) and 1-(2-pyridylazo)-2-naphthol (PAN) was prepared for the preconcentration of trace uranyl(VI) from water samples. The uranium(VI) was completely eluted with 6.0 mol dm-3 HCl and determined by a spectrophotometric method with Arsenazo III. The SPE conditions were optimized by evaluating the effective factors such as pH, flow rate and masking agent. By the proposed method a preconcentration factor more than 150 was achieved. The average recovery of uranium(VI) was 99.8%. The relative standard deviation was 2.6% for ten replicate determinations of uranyl(VI) ion in a solution with a concentration of 50 ng cm-3. Some concomitant ions such as Cd2+, Ni2+, MoO42-, Cu2+, Th4+ and Ce3+, which interfere in the determination process of uranium(VI), were masked with EDTA in the aqueous phase during the extraction process. The proposed method was successfully used for the determination of uranium in natural water. (author)

175

Application of solid-phase extraction for determination of phenolic compounds in barrique wines.  

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A fast, selective and sensitive chromatographic method has been developed for determination of gallic, protocatechuic, p-hydroxybenzoic, vanillic, caffeic, syringic, p-coumaric, benzoic, ferulic, sinapic, cinnamic, and ellagic acids and p-hydroxybenzaldehyde, vanillin, syringaldehyde, 2-furfural, 5-methylfurfural, and 5-methoxyfurfural. The compounds from untreated wine samples were pre-concentrated and cleaned using solid-phase extraction on RP-105 polymeric sorbent. The cartridge was conditioned with methanol and water. Co-extracted ballast substances were rinsed from the sorbent with 0.1 mol L(-1) hydrochloric acid-methanol, 1:4 (v/ v). Retained phenolic compounds were selectively eluted with diethyl ether. A linear mobile phase gradient containing 0.3% acetic acid and methanol was used for final baseline chromatographic separation on a Hypersil BDS C18 column. Limits of detection (LOD=3 s(bl)) in the range 5.2 to 181.2 microg L(-1), resolution (R) better than 1.7, and repeatability of 2.7-5.1% (RSD for real samples) were achieved. The method was applied for quantification of individual phenolic compounds in barrique wines. PMID:12923605

Matejícek, D; Klejdus, B; Mikes, O; Sterbová, D; Kubán, V

2003-09-01

176

On-line solid-phase extraction for liquid chromatography-mass spectrometry analysis of pesticides.  

Science.gov (United States)

Public concern about pesticides in food and water has increased dramatically in the last two decades. In order to guarantee consumers' health and safety, analytical methods that could provide fast and reliable answers without compromising accuracy and precision are required. Sample treatment is probably the most tedious and time-consuming step in many analytical procedures and, despite the significant advances in chromatographic separations and mass spectrometry techniques, sample treatment is still one of the most important parts of the analytical process for achieving good analytical results. Therefore, over the last years, considerable efforts have been made to simplify the stage and to develop fast, accurate, and robust methods that allow the determination of a wide range of pesticides without compromising the integrity of the extraction process. This review article intends to give a short overview of recently developed on-line solid-phase extraction, preconcentration, and clean-up procedures for the determination of pesticides in complex matrices by liquid chromatography-mass spectrometry techniques. PMID:25103367

Lucci, Paolo; Núñez, Oscar

2014-10-01

177

Development of magnetic micro-solid phase extraction for analysis of phthalate esters in packaged food.  

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A novel, simple and low cost magnetic multi-walled carbon nanotubes-poly (vinyl alcohol) cryogel-micro-solid phase extraction (magnetic-MWCNTs-PVA cryogel-?-SPE) sorbent was synthesized by incorporating magnetic particles and MWCNTs into a PVA cryogel. The magnetic-MWCNTs-PVA cryogel-?-SPE sorbent developed, with a large surface area and macro-porous structure, provided good sorbent-to-sorbent reproducibility (%RSD<8) and each sorbent could be used up to 30 times (%RSD<6). This sorbent was applied for the extraction of dibutyl phthalate (DBP) and di-2-(ethylhexyl) phthalate (DEHP) in packaged food prior to analysis by gas chromatograph coupled with flame ionisation detector (GC-FID). The concentration of DBP and DEHP in hot-water samples from plastic bags were found in the range 0.04-0.15 ?g mL(-1) and 0.03-0.20 ?g mL(-1), respectively, but only DEHP was found in clear chicken soup samples in the range 0.02-0.07 ?g mL(-1). PMID:25053056

Makkliang, Fonthip; Kanatharana, Proespichaya; Thavarungkul, Panote; Thammakhet, Chongdee

2015-01-01

178

Chemically functionalized ? alumina with alizarin red-S for selective complexion solid phase extraction of Pb (II), Ag(I) and determination by flame atomic absorption spectrometry  

International Nuclear Information System (INIS)

Complete text of publication follows. A new and efficient solid phase extraction method is described for the preconcentration of Pb(II), Ag(I). ? Alumina was firstly functionalized with sodium dodecyle sulfate and then adding the alizarin red-S solution in ethanol, the solid phase was prepared to adsorb trace heavy metals in the samples. The metal sorption properties of modified alumina were studied towards Pb(II), Ag (I). For batch method, the optimum pH was 7 and the contact times to rich the equilibrium were about 15 min. Various parameter such as amount of adsorbent, ligand, surfactant, eluent type and volume, flow rate of sample solution, volume of the sample solution and matrix interference effect on the retention of the metal ions have been studied. The linear range was 100-1500, and 300-3000 ng mL-1 for lead and silver, respectively. The preconcentration factor 35 and 32 for lead and silver, respectively. The limit of detection was 45 and 150 ng mL-1 for lead and silver respectively. This method was successfully applied for separation and determination of Pb(II), Ag (I) in some real samples.

179

Studies on the separation of rare earth elements and yttrium using a new solid phase adsorbent xylenol orange immobilized on silica: application to geological samples  

International Nuclear Information System (INIS)

This paper presents the investigation carried out on a new solid phase adsorbent developed in our laboratory, xylenol orange immobilized on silica (XO-Si) by a single step process. Preparation of silica from sodium meta-silicate solution and immobilization of xylenol orange on it takes place simultaneously in presence of cationic surfactant cetyl-tri-methyl ammonium bromide (CTAB). It was observed that in the absence of surfactant, xylenol orange was completely removed from the silica surface during washing. The surfactant CTAB acts as a bridge between silica and xylenol orange molecule

180

Design of a new cartridge for selective solid phase extraction using molecularly imprinted polymers: selective extraction of theophylline from human serum samples.  

Science.gov (United States)

This paper describes design of a new cartridge for selective solid phase extraction (SPE) using molecularly imprinted polymers (MIPs). The apparatus which is termed solvent extraction-MISPE (SE-MISPE) cartridge, consisted of a modified conventional micro test tube and has been developed to perform simultaneous forward-extraction of analyte from aqueous sample solution to an organic phase and back-extraction to MIP solid phase. In order to evaluate the performance of the proposed method, extraction of theophylline (THP) from human serum sample was investigated. An appropriate amount of THP-imprinted polymer was placed in the bottom of the micro tube and an organic solvent pipetted onto it and left to swell the polymer completely. A polyethylene frit to secure MIP particles was positioned by two Teflon rings such that it was fixed below the level of the organic layer. Then, aqueous sample solution containing THP was layered over the organic phase and the lid was closed. After completion of extraction, the organic and aqueous phases were removed and the adsorbed analyte was desorbed using a polar organic solvent. In order to reach the highest recovery, the experimental parameters such as the type of organic solvent, pH and ionic strength of aqueous phase, organic to aqueous volume ratio, time of extraction, type and amount of desorbent solvent were optimized. Under the experimental conditions, a plot of HPLC peak areas vs. initial concentrations of THP in the concentration interval of 0.5-30 microg ml(-1) showed a good linearity (r=0.9974). The limit of detection (LOD) and limit of quantification (LOQ) based on three and ten times of the noise of HPLC profile were 0.09 and 0.3 microg ml(-1), respectively. The relative standard deviation (RSD) of the proposed method for the extraction and determination of 5 microg THP from 200 microl standard sample solution for 3 replicate measurements was 3.5%. The results showed that by means of the proposed cartridge, THP could significantly separate from the other structurally related compounds such as theobromine (THB) and caffeine (CAF). The added THP could be quantitatively recovered (79-83%) from the serum samples by the proposed procedure, being thus a guarantee of the accuracy of the SE-MISPE procedure. In addition, the loss of capability of the SE-MISPE cartridge was not considerably observed after 10 times loading and elution cycles. PMID:19157845

Khorrami, Afshin Rajabi; Rashidpur, Amene

2009-11-15

 
 
 
 
181

Sample digestion and solid-phase extraction for the enrichment of actinides from radioactive waste  

International Nuclear Information System (INIS)

For the destructive characterization of radioactive waste, the actinides to be analysed must be separated from matrix components, if possible, in an element-specific manner. Microwave pressure digestion is a time-saving digestion method for radioactive waste samples. This method serves to digest solid samples in teflon pressure autoclaves with the addition of various acids. Different microwave programs have been developed for all common radioactive waste matrices such as cement, ion exchange resins, filter dusts, sludges and mineral blasting sands permitting digestion times of approx. 1.5 hours including time for cooling. The partitioning of the actinides from the liquid samples was carried out with the aid of solid-phase extraction. For the experiments, on the one hand, commercially available extraction resins such as Actinide, TRU, UTEVA and TEVA resinTM from Eichrom were used. On the other hand, an extraction resin with Cyanex 301 produced in-house was employed specifically for actinide-lanthanide partitioning. It was possible to separate 99.4% of the lanthanides by a two-stage partitioning process. A partitioning run using the Eichrom resins was successfully adapted to the waste matrices and automated with the aid of a laboratory robot. It is particularly meaningful to perform a prior matrix partitioning with Actinide resinTM. A rough qualification of the sample is possible by the ?-analysis of the actinide fraction. The extractant, which was eluted from the column together with the actinides, was destroyed oxidatively by means of a newly developed technique using microwave pressure digestion. The final determination of the actinides was performed with the aid of ?-spectrometry. Electrodeposition proved to be a suitable method for the preparation of samples with minimum possible layer thickness. This preparation technique was optimized so as to provide samples with half-widths of 18 keV in the ?-spectrometer. (orig.)

182

Cyclodextrin polymer/Fe3O4 nanocomposites as solid phase extraction material coupled with UV-vis spectrometry for the analysis of rutin  

Science.gov (United States)

In this paper, carboxymethyl-hydroxypropyl-?-cyclodextrin polymer modified magnetic particles Fe3O4 (CM-HP-?-CDCP-MNPs) were prepared and applied to magnetic solid phase extraction of rutin combined with UV-visible spectrometry detection. The synthesized magnetic particles were characterized by element analysis, Fourier transform infrared spectra, thermal gravimetric analysis, and transmission electron microscopy. Several variables affecting the extraction and desorption of rutin such as pH, the amount of adsorbent, the type and volume of eluent, extraction and desorption time, and temperature were investigated. The maximum adsorption capacity was 67.0 mg g-1 for rutin with the equilibrium time of 30 min at room temperature, and the adsorbent could be reused for 10 times. A calibration curve was linear in the range of 0.05-8.00 ?g mL-1 with a relative standard deviation of 2.9% (n = 5, c = 4.0 ?g mL-1). The limit of detection was 7.0 ng mL-1. The interaction mechanism between the adsorbent and rutin was also studied. Feasibility of this method was validated by the analysis of rutin tablets and lotus plumule.

Gong, Aiqin; Ping, Wenhui; Wang, Jue; Zhu, Xiashi

2014-03-01

183

Preparation of molecularly imprinted solid phase extraction using bensulfuron-methyl imprinted polymer and clean-up for the sulfonylurea-herbicides in soybean.  

Science.gov (United States)

A pre-treatment methodology based on the molecularly imprinted solid phase extraction (MI-SPE) procedure was developed for the determination of bensulfuron-methyl (BSM), tribenuron-methyl (TBM), metsulfuron-methyl (MSM) and nicosulfuron (NS) in soybean samples. A molecular imprinted polymer (MIP) was prepared by precipitation polymerization using BSM as the template molecule, alpha-methacrylic acid (MAA) as the functional monomer, trimethylolpropane trimethacrylate (TRIM) as the cross-linker and dichloromethane as the porogen. The binding behaviors of the template BSM and its analogues on the MIP were evaluated by high performance liquid chromatography (HPLC). Then, solid phase extraction (SPE) with a BSM molecularly imprinted polymer (BSM-MIP) as adsorbent was investigated and the optimum loading, washing, and eluting conditions for MI-SPE of the selected BSM, MSM, TBM, and NS were established. The optimized MI-SPE procedure was used to extract the sulfonylureas and a high recovery was obtained in the soybean samples. PMID:18405688

Tang, Kaijie; Chen, Shangwei; Gu, Xiaohong; Wang, Haijun; Dai, Jun; Tang, Jian

2008-04-28

184

Extraction and on-fiber derivatization of chlorophenols in leather by internally cooled solid phase microextraction  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Neste estudo é proposto um novo procedimento analítico para a determinação de fenóis em amostras de couro utilizando a técnica de microextração em fase sólida refrigerada internamente (CF-SPME) com derivatização direta na fibra e cromatografia gasosa acoplada a espectrometria de massas com monitoram [...] ento de íons selecionados (GC-SIM-MS). As condições experimentais para a extração e derivatização foram otimizadas utilizando procedimentos quimiométricos, sendo tempo de extração e temperatura da amostra de 5 min e 170 ºC, temperatura do recobrimento da fibra de 20 ºC, e exposição da fibra ao headspace de 70 µL do agente derivatizante bis(trimetilsilil)trifluor-acetamida por 23 min. Limites de detecção variaram entre 1,03 e 2,68 µg g-1 e o desvio padrão relativo (RSD) foi menor que 15% (n = 5). Estudos de recuperações em três níveis de concentração variaram entre 64,5 e 92,3%. Abstract in english This study proposes a new analytical procedure based on an internally cooled solid phase microextraction technique (CF-SPME) combined with on-fiber derivatization and gas chromatography-selected ion monitoring-mass spectrometry (GC-SIM-MS) for the determination of phenols extracted directly from lea [...] ther samples. The extraction and derivatization conditions were optimized using experimental designs, such as: extraction time and sample temperature of 5 min and 170 ºC, fiber recoat temperature of 20 ºC, and exposing the fiber to the headspace of 70 µL of bis(trimethylsylyl)trifluoro-acetamide derivatizing agent for 23 min. Detection limits ranging from 1.03 to 2.68 µg g-1 and relative standard deviation (RSD) lower than 15% (n = 5) were obtained. The recovery was studied at three concentration levels and excellent recoveries ranging from 64.5 to 92.3% were obtained.

Cristine D. de Souza, Silveira; Josias, Merib; Edmar, Martendal; Eduardo, Carasek.

2232-22-01

185

Extraction and on-fiber derivatization of chlorophenols in leather by internally cooled solid phase microextraction  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Neste estudo é proposto um novo procedimento analítico para a determinação de fenóis em amostras de couro utilizando a técnica de microextração em fase sólida refrigerada internamente (CF-SPME) com derivatização direta na fibra e cromatografia gasosa acoplada a espectrometria de massas com monitoram [...] ento de íons selecionados (GC-SIM-MS). As condições experimentais para a extração e derivatização foram otimizadas utilizando procedimentos quimiométricos, sendo tempo de extração e temperatura da amostra de 5 min e 170 ºC, temperatura do recobrimento da fibra de 20 ºC, e exposição da fibra ao headspace de 70 µL do agente derivatizante bis(trimetilsilil)trifluor-acetamida por 23 min. Limites de detecção variaram entre 1,03 e 2,68 µg g-1 e o desvio padrão relativo (RSD) foi menor que 15% (n = 5). Estudos de recuperações em três níveis de concentração variaram entre 64,5 e 92,3%. Abstract in english This study proposes a new analytical procedure based on an internally cooled solid phase microextraction technique (CF-SPME) combined with on-fiber derivatization and gas chromatography-selected ion monitoring-mass spectrometry (GC-SIM-MS) for the determination of phenols extracted directly from lea [...] ther samples. The extraction and derivatization conditions were optimized using experimental designs, such as: extraction time and sample temperature of 5 min and 170 ºC, fiber recoat temperature of 20 ºC, and exposing the fiber to the headspace of 70 µL of bis(trimethylsylyl)trifluoro-acetamide derivatizing agent for 23 min. Detection limits ranging from 1.03 to 2.68 µg g-1 and relative standard deviation (RSD) lower than 15% (n = 5) were obtained. The recovery was studied at three concentration levels and excellent recoveries ranging from 64.5 to 92.3% were obtained.

Cristine D. de Souza, Silveira; Josias, Merib; Edmar, Martendal; Eduardo, Carasek.

186

Combined liquid and solid-phase extraction improves quantification of brain estrogen content.  

Science.gov (United States)

Accuracy in quantifying brain-derived steroid hormones ("neurosteroids") has become increasingly important for understanding the modulation of neuronal activity, development, and physiology. Relative to other neuroactive compounds and classical neurotransmitters, steroids pose particular challenges with regard to isolation and analysis, owing to their lipid solubility. Consequently, anatomical studies of the distribution of neurosteroids have relied primarily on the expression of neurosteroid synthesis enzymes. To evaluate the distribution of synthesis enzymes vis-à-vis the actual steroids themselves, traditional steroid quantification assays, including radioimmunoassays, have successfully employed liquid extraction methods (e.g., ether, dichloromethane, or methanol) to isolate steroids from microdissected brain tissue. Due to their sensitivity, safety, and reliability, the use of commercial enzyme-immunoassays (EIA) for laboratory quantification of steroids in plasma and brain has become increasingly widespread. However, EIAs rely on enzymatic reactions in vitro, making them sensitive to interfering substances in brain tissue and thus producing unreliable results. Here, we evaluate the effectiveness of a protocol for combined, two-stage liquid/solid-phase extraction (SPE) as compared to conventional liquid extraction alone for the isolation of estradiol (E(2)) from brain tissue. We employ the songbird model system, in which brain steroid production is pronounced and linked to neural mechanisms of learning and plasticity. This study outlines a combined liquid-SPE protocol that improves the performance of a commercial EIA for the quantification of brain E(2) content. We demonstrate the effectiveness of our optimized method for evaluating the region specificity of brain E(2) content, compare these results to established anatomy of the estrogen synthesis enzyme and estrogen receptor, and discuss the nature of potential EIA interfering substances. PMID:21909323

Chao, Andrew; Schlinger, Barney A; Remage-Healey, Luke

2011-01-01

187

Solid phase extraction of trace amount of Cu(II) using functionalized-graphene  

Science.gov (United States)

A novel and selective method for the fast determination of trace amounts of Cu(II) ions in water samples has been developed. The first organic-solution-processable functionalized-graphene (SPF-Graphene) hybrid material with porphyrins, porphyrin-graphene nanohybrid, 5-(4-aminophenyl)-10, 15, 20-triphenyl porphyrin and its photophysical properties including optical (TPP) and grapheme oxide molecules covalently bonded together via an amide bond (TPP-NHCO-SPFGraphene) were used as absorbent for extraction of Cu(II) ions by solid phase extraction method. The complexes were eluted with HNO3 (2 M) 10% (vol/vol) methanol in acetone and determined the analyte by flame atomic absorption spectrometry. The procedure is based on the selective formation of Cu(II) at optimum pH by elution with organic eluents and determination by flame atomic absorption spectrometry. The method is based on complex formation on the surface of the ENVI-18 DISK™ disks modified porphyrin-graphene nanohybrid, 5-(4-aminophenyl)-10,15,20-triphenyl porphyrin (TPP) and grapheme oxide molecules covalently bonded together via an amide bond (TPP-NHCO-SPFGraphene) followed by stripping of the retained species by minimum amounts of appropriate organic solvents. The elution is efficient and quantitative. The effect of potential interfering ions, pH, TPP-NHCO-SPFGraphene, amount, stripping solvent, and sample flow rate were also investigated. Under the optimal experimental conditions, the break-through volume was found to about 1000 mL providing a preconcentration factor of 600. The maximum capacity of the disks was found to be 398 ± 3 ?g for Cu2+. The limit of detection of the proposed method is 5 ng per 1000 mL. The method was applied to the extraction and recovery of copper in different water samples.

Moghimi, Ali

2013-11-01

188

[Preparation and application of solid phase extraction packing of zirconia microsphere coated with sulfonated crosslinked polystyrene].  

Science.gov (United States)

Zirconia microsphere was prepared by polymerization-induced colloid aggregation (PICA) method and carbon-carbon double bond was grafted onto its surface by titanic acid ester coupling reagent. Poly(styrene-divinylbenzene) was synthesized by free radical polymerization by using styrene, divinylbenzene and carbon-carbon double bond on the microsphere surface in solution system, so the polymer was coated on the microsphere surface. After the benzene ring of the polymer was sulfonated, the cation exchange packing for solid phase extraction (SPE) was obtained. The material was characterized by Fourier transform infrared spectroscopy, scanning electron microscope and X-ray energy dispersive spectroscopy. Three herbicides of mesotrione, atrazine and acetochlor in water were determined by the SPE cartridge coupled with high performance liquid chromatography (HPLC). In the range of 0.5 - 3.0 mg/L, the relationships between the peak areas and mass concentrations of mesotrione, atrazine and acetochlor were linear with the correlation coefficients of 0.9936, 0.9925, 0.9919, respectively. The limits of detection were 5.41, 6.72 and 13.4 microg/L for mesotrione, atrazine and acetochlor, respectively. The results showed that the zirconium dioxide microspheres coated with polymer have diameters in the range of about 6 to 8 microm, the SPE cartridges of which have high adsorption rate for the targets. PMID:24369611

Shen, Shuchang; Liu, Yuhui; Xiao, Xiaoxing

2013-08-01

189

Collecting peptide release from the brain using porous polymer monolith-based solid phase extraction capillaries  

Science.gov (United States)

Porous polymer monolithic (PPM) columns are employed to collect and concentrate neuronal release from invertebrate and vertebrate model systems, prior to their characterization with mass spectrometry. The monoliths are fabricated in fused silica capillaries from lauryl methacrylate (LMA) and ethylene glycol dimethacrylate (EDMA). The binding capacities for fluorescein and for fluorescently labeled peptides are on the order of nanomoles per millimeter length of monolith material for a 200 ?m inner diameter capillary. To evaluate this strategy for collecting peptides from physiological solutions, angiotensin I and insulin in artificial seawater are loaded onto, and then released from the monoliths after a desalination rinse, resulting in femtomole limits of detection via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Positioned in the extracellular media near Aplysia californica bag cell neurons, upon electrical stimulation, these LMA-EDMA monoliths are also used to collect and concentrate peptide release, with egg laying hormone and acidic peptide detected. In addition, the collection of several known peptides secreted from chemically stimulated mouse brain slices demonstrates their ability to collect releasates from a variety of neuronal tissues. When compared to collection approaches using individual beads placed on brain slices, the PPM capillaries offer greater binding capacity. Moreover, they maintain higher spatial resolution as compared to the larger-volume, solid phase extraction collection strategies. PMID:19485405

Iannacone, Jamie M.; Ren, Shifang; Hatcher, Nathan G.; Sweedler, Jonathan V.

2010-01-01

190

Molecularly imprinted polymers-curcuminoids and its application for solid phase extraction  

Science.gov (United States)

Molecularly Imprinted Polymers (MIPs) for the selective recognition properties of curcumin (CUR), a cancer chemopreventive agent were obtained by a non-covalent imprinting approach with bisdemetoxycurcumin (BDMC) as the template molecule. The double bond of BDMC has been reduced in order not to be involved in polymerization and make the template molecules easy to be eluted. Several functional monomers have been evaluated to maximize the interactions with the template molecule during polymerization. MIPs prepared by bulk of N-(2-aminoethyl) metacrylamid hydrochlorideas functional monomer, ethylene glycol dimethacrylate as crosslinker, 2,2'-azobis (2'4-dimethyl valeronitril) as initiator and acetonitrile as porogen. Non-imprinted polymer (NIP) have been also synthesized for reference purposes. UV-vis spectroscopy has been used to predict the template to functional monomer ratio which indicates the formation of 2:1 complexes between monomer and curcumin and the association constants (K11 = 2529 ?M and K12 = 1960.75 ?M in acetonitrile). The capacity and imprinting factor have been evaluated as stationary phases in high-pressure liquid chromatography to CUR and BDMC. The binding properties and the homogeneity of the binding sites of the different polymers have been studied by Freundlich isotherm modeling and weight average affinity and number of binding sites. One of the foremost applications of molecular imprinting has been in molecularly imprinted solid phase extraction and it has the ability to separate and preconcentrate between closely related compounds in curcuminoids.

Wulandari, Meyliana; Amran, M. B.; Lopez, A. B. Descalzo; Urraca, J. L.; Moreno-Bondi, M. C.

2014-03-01

191

Recent developments in automatic solid-phase extraction with renewable surfaces exploiting flow-based approaches  

DEFF Research Database (Denmark)

Solid-phase extraction (SPE) is the most versatile sample-processing method for removal of interfering species and/or analyte enrichment. Although significant advances have been made over the past two decades in automating the entire analytical protocol involving SPE via flow-injection approaches,on-line SPE assays performed in permanent mode lack sufficient reliability as a consequence of progressively tighter packing of the bead reactor, contamination of the solid surfaces and potential leakage of functional moieties. This article overviews the current state-of-the-art of an appealing tool for overcoming the above shortcomings, so-called bead-injection (BI) analysis, based on automated renewal of the sorbent material per assay exploiting the various generations of flow-injection analysis. It addresses novel instrumental developments for implementing BI and a number of alternatives for online chemical-derivatization reactions, and it pinpoints the most common instrumental detection techniques utilized. We present and discuss in detail relevant environmental and bioanalytical applications reported in the past few years.

Miró, Manuel; Hartwell, Supaporn Kradtap

2008-01-01

192

Determination of Inorganic Arsenic in Natural Water by Solid Phase Extraction  

International Nuclear Information System (INIS)

Arsenic (As) is generally known for its toxicity. The toxicity and mobility of As in the environment are dependent on the chemical forms or species in which it exists. Arsenic (III) and (V) are the most often determined species in environmental water, soil and sediment, while organic As species are common constituents of biological tissue and fluids. It is well known that inorganic As, such as arsenite (As(III)) and arsenate (As(V)) are more toxic than their organic counterparts. This study is conducted to investigate the separation of each As inorganic species using solid phase extraction (SPE) technique. The technique utilizes SPE column for selective retention of As species, followed by elution and measurement of eluted fractions by inductively coupled plasma mass spectrometry (ICP-MS) for total As. Several type of SPE columns namely strongly anion exchange (SAX), strongly cation exchange (SCX), weakly anion exchange (WAX) and weakly cation exchange (WCX) were tested using three different types of media including deionized water, succinic acid and acetic acid containing inorganic As species. The SPE technique is suitable for on-site separation and preservation of As species from water. (author)

193

Tandem Solid Phase Extraction for the Determination of Pharmaceuticals in Wastewater  

International Nuclear Information System (INIS)

In this study, a simple and rapid tandem solid phase extraction (SPE) was developed for the analysis of seven pharmaceuticals (acetaminophen, caffeine, carbamazepine, diclofenac, naproxen, ibuprofen and metaprolol) in wastewater sample. The novel aspect of coupling SPE cartridge in tandem is the ability to simplify the SPE procedure (sample introduction step) as no single sorbent was able to retain and concentrate all selected compounds since these compounds are of different physicochemical properties. A tandem SPE cartridges using Oasis HLB and octadecyl bonded silica (C18) was found to be efficient with the advantages of minimizing sample volume and reducing analysis time. Using this approach, carbamazepine, diclofenac, naproxen and metaprolol were trapped in the Oasis HLB while acetaminophen, caffeine and ibuprofen were trapped in the second cartridge (C18). The instrumental limits of detection (LOD) ranged from 0.01 to 0.04 ?g/ L and satisfactory recoveries were obtained between 76 % to 104 %. The calibration curves were linear from 0.1 to 5.0 ?g/ mL, with correlation coefficients (R2) in the range of 0.995 to 0.999. The developed method was applied to the analysis of pharmaceuticals in wastewater samples. The amount of pharmaceuticals detected in wastewater samples varied from 0.4 to 24.5 mg/ L. (author)

194

Determination of rhodamine B in soft drink, waste water and lipstick samples after solid phase extraction.  

Science.gov (United States)

A new solid phase extraction method is described for sensitive and selective determination of trace levels of rhodamine B in soft drink, food and industrial waste water samples. The method is based on the adsorption of rhodamine B on the Sepabeads SP 70 resin and its elution with 5 mL of acetonitrile in a mini chromatographic column. Rhodamine B was determined by using UV visible spectrophotometry at 556 nm. The effects of different parameters such as pH, amount of rhodamine B, flow rates of sample and eluent solutions, resin amount, and sample volume were investigated. The influences of some alkali, alkali earth and transition metals on the recoveries of rhodamine B were investigated. The preconcentration factor was found 40. The detection limit based on three times the standard deviation of the reagent blank for rhodamine B was 3.14 ?g L?¹. The relative standard deviations of the procedure were found as 5% in 1×10?? mol L?¹ rhodamine B. The presented procedure was successfully applied to real samples including soft drink, food and industrial waste water and lipstick samples. PMID:21570440

Soylak, Mustafa; Unsal, Yunus Emre; Yilmaz, Erkan; Tuzen, Mustafa

2011-08-01

195

Rapid gas chromatography/mass spectrometry quinine determination in plasma after automated solid-phase extraction.  

Science.gov (United States)

The combined use of an automatic solid-phase extraction (SPE) apparatus with Oasis MCX cartridges and gas chromatography/mass spectrometry (GC/MS) to rapidly quantify quinine in biological samples with cyproheptadine as the internal standard is described. The selected ion monitoring mode, with the quantification ions m/z 136 and 287 (qualifier ions: m/z 261, 381 and 215, 96), allows the estimation of quinine levels, respectively. Separation was completed within 12.7 min. Excellent linearity was found up to 10 000 microg/L of plasma. The limit of detection (LOD) was 12.2 microg/L and the limit of quantification (LOQ) was 40.6 microg/L. High reproducibility (intra-assay CV range 1.9-4.3%, inter-assay CV range 2.2-11.3%) and accuracy values (intra-assay range 83.2-103.7%, inter-assay range 86.8-103.7%) were obtained. Recoveries were concentration-independent (97.2% and 89.8% for 4000 and 10 000 microg/L, respectively). This sensitive, simple assay for quinine in various matrices meets the current requirements for bioanalytical assays and may be used to monitor quinine levels in patients developing severe malaria with acute renal failure during hemofiltration. The optimal quinine dose in this situation is not really established and to improve clinical care, quinine concentrations might be explored to improve efficacy and minimise potential toxicity. PMID:16878344

Damien, Richard; Daval, Sandrine; Souweine, Bertrand; Deteix, Patrice; Eschalier, Alain; Coudoré, François

2006-01-01

196

Solid-phase extraction procedure for determination of phenolic acids and some flavonols in honey.  

Science.gov (United States)

The solid-phase extraction procedure (SPE) for isolation and preconcentration of phenolic acids (gallic, p-HBA, p-coumaric, vanillic, caffeic and syringic acid) and some flavonols (rutin, quercetin and kaempferol) from honey samples prior to their determination by HPLC is reported. Different solid sorbents such as Bond Elut octadecyl C(18), Oasis HLB, Strata-X and Amberlite XAD-2 were tested for this purpose. The best results were obtain when aqueous solution of honey (100 mL) was adjusted to pH 2 and passed through the microcolumn containing 2.5 g of Oasis HB followed by washing the sorbent with 50 mL of acidified water (pH 2). The analytes were then eluted with methanol. The proposed method permits the quantification of the studied compounds with the limit of detections ranged from 25 ng kg(-1) to 0.75 microg kg(-1) for p-HBA and quercetin, respectively. The precision of the overall analytical procedure was estimated by measuring the within-day repeatability and the relative standard deviations of the parallel (n=3) results were in the range of 1.9-10.1%. The method was tested for real honey samples from different botanical origins. PMID:18282581

Michalkiewicz, Anna; Biesaga, Magdalena; Pyrzynska, Krystyna

2008-04-11

197

Gas chromatographic determination of N-nitrosamines in beverages following automatic solid-phase extraction.  

Science.gov (United States)

A semiautomatic method for the determination of seven N-nitrosamines in beverages by gas chromatography with nitrogen-phosphorus detection is proposed. Beverage samples are aspirated into a solid-phase extraction module for preconcentration and cleanup. The influence of the experimental conditions was examined by using various sorbents among which LiChrolut EN was found to provide quantitative elution and the highest preconcentration factors of all. The proposed method is sensitive, with limits of detection between 7 and 33 ng/kg, and precise, with relative standard deviations from 4.3% to 6.0%. The recoveries of N-nitrosamines from beverage samples spiked with 0.5 or 1 microg/kg concentrations of these compounds ranged from 95% to 102%. The method was successfully applied to the determination of residues of the studied N-nitrosamines in beverages including beer, wine, liquor, whisky, cognac, rum, vodka, grape juice, cider, tonic water, and soft drinks. The analytes were only detected in beer samples, positives being confirmed by gas chromatography coupled with impact ionization mass spectrometry. PMID:17960883

Jurado-Sánchez, Beatriz; Ballesteros, Evaristo; Gallego, Mercedes

2007-11-28

198

Solid-phase extraction of antipyrine dye for spectrophotometric determination of phenolic compounds in water.  

Science.gov (United States)

In order to determine phenolic compounds in water, we propose a method based on the reaction of phenolic compounds with 4-aminoantipyrine in the presence of peroxodisulfate at pH 10 to form antipyrine dye and the solid-phase extraction of dye with a Varian Bond Elut Plexa cartridge. Dye collected on the cartridge is eluted with acetonitrile and the absorbance is measured at 475 nm. In our experiments, recovery ratios of >90% were obtained for phenol, o-aminophenol, m-aminophenol, o-methoxyphenol, m-methoxyphenol, p-methoxyphenol, o-cresol, m-cresol, o-chlorophenol, m-chlorophenol, p-chlorophenol, 2,5-dimethylphenol, and 2,4-dichlorophenol. The calibration curve obeyed Beer's law in the range 0 - 0.30 µg ml(-1) phenol. The precision of repeated tests (n = 4) was 1.7% of the phenol solution (0.10 µg ml(-1)); the detection limit was 0.0011 µg ml(-1). Recovery tests using river water, waste water, and sewage influent gave highly satisfactory results. PMID:21558654

Morita, Emi; Nakamura, Eiko

2011-01-01

199

Magnetic solid-phase extraction of sulfonylurea herbicides in environmental water samples by Fe3O4@dioctadecyl dimethyl ammonium chloride@silica magnetic particles.  

Science.gov (United States)

A magnetic solid phase extraction (MSPE) method coupled with high-performance liquid chromatography (HPLC) was proposed for the determination of five sulfonylurea herbicides (bensulfuron-methyl, prosulfuron, pyrazosulfuron-ethyl, chlorimuron-ethyl and triflusulfuron-methyl) in environmental water samples. The magnetic adsorbent was prepared by incorporating Fe(3)O(4) nanoparticles and surfactant into a silica matrix according to a sol-gel procedure, which can provide surfactant free extracts during the eluting step to avoid chromatographic interference. The prepared adsorbent was used to extract the sulfonylurea herbicides in several kinds of water samples. The main factors affecting the extraction efficiency, including desorption conditions, extraction time, sample volume, and sample solution pH were optimized. Under the optimum conditions, good linearity was obtained within the range of 0.2-50.0 ?g L(-1) for all analytes, with correlation coefficients ranging from 0.9993 to 0.9999. The enrichment factors were between 1200 and 1410, and the limits of detection were between 0.078 and 0.10 ?g L(-1). The proposed method was successfully applied in the analysis of sulfonylurea herbicides in environmental samples (tap, reservoir, river, and rice field). The recoveries of the method ranged between 80.4% and 107.1%. This study reported for the first time the use of MSPE procedure in the preconcentration of sulfonylurea herbicides in environmental samples. The procedure proved to be efficient, environmentally friendly, and fast. PMID:22986132

He, Zeying; Liu, Donghui; Li, Ranhong; Zhou, Zhiqiang; Wang, Peng

2012-10-17

200

Magnetic single-walled carbon nanotubes-dispersive solid-phase extraction method combined with liquid chromatography-tandem mass spectrometry for the determination of paraquat in urine.  

Science.gov (United States)

In this study, magnetic single-walled carbon nanotubes (MSWCNTs) were prepared by impregnating magnetic Fe3O4 nanoparticles onto the surfaces of carboxylic single-walled carbon nanotubes based on electrostatic interactions. The prepared MSWCNTs were used as the adsorbent for the dispersive solid-phase extraction (DSPE) of paraquat from human urine. After adsorption, the paraquat was quantitatively desorbed with 5%TFA in acetonitrile and determined by HPLC-MS. Extraction parameters such as the type of CNT adsorbent, extraction time, sample volume, wash solvent, and the type and volume of desorption solvent were optimized to obtain high DSPE recoveries and extraction efficiencies. Under the optimized conditions, the calibration curve was linear in the range 3.75-375.0 ?g/L with a correlation coefficient of 0.999 45. The LOD (S/N=3) and LOQ (S/N=10) were 0.94 and 2.82 ?g/L, respectively. The recoveries ranged from 92.89 to 108.9% for spiked real urine samples with RSDs below 3.21%. Finally, the new method was successfully used to determine paraquat in urine samples of suspected paraquat poisoning patients. The MSWCNTs exhibited suitable properties and a high adsorption capacity for the extraction of paraquat. PMID:24999616

Ruan, Xiao-Lin; Qiu, Jing-Jing; Wu, Chuan; Huang, Tao; Meng, Rui-Bo; Lai, Yong-Qiang

2014-08-15

 
 
 
 
201

Magnetically assisted solid phase extraction using Fe3O4 nanoparticles combined with enhanced spectrofluorimetric detection for aflatoxin M1 determination in milk samples.  

Science.gov (United States)

A novel, facile and inexpensive solid phase extraction (SPE) method using ethylene glycol bis-mercaptoacetate modified 3-(trimethoxysilyl)-1-propanethiol grafted Fe(3)O(4) nanoparticles coupled with spectrofluorimetric detection was proposed for determination of aflatoxin M1 (AFM1) in liquid milk samples. The method uses the advantage fluorescence enhancement by ?-cyclodexterin complexation of AFM1 in 12% (v/v) acetonitrile-water and the remarkable properties of Fe(3)O(4) nanoparticles namely high surface area and strong magnetization were utilized to achieve high enrichment factor (57) and satisfactory extraction recoveries (91-102%) using only 100 mg of magnetic adsorbent. Furthermore, fast separation time of about 15 min avoids many time-consuming column-passing procedures of conventional SPE. The main factors affecting extraction efficiency including pH value, desorption conditions, extraction/desorption time, sample volume, and adsorbent amount were evaluated and optimized. Under the optimal conditions, a wide linear range of 0.04-8 ng mL(-1) with a low detection limit of 0.015 ng mL(-1) was obtained. The developed method was applied for extraction and preconcentration of AFM1 in three commercially available milk samples and the results were compared with the official AOAC method. PMID:25127653

Taherimaslak, Zohreh; Amoli-Diva, Mitra; Allahyary, Mehdi; Pourghazi, Kamyar

2014-09-01

202

DETERMINATION OF CHLOROETHENES IN ENVIRONMENTAL BIOLOGICAL SAMPLES USING GAS CHROMATOGRAPHY COUPLED WITH SOLID PHASE MICRO EXTRACTION  

Science.gov (United States)

An analytical method has been developed to determine the chloroethene series, tetrachloroethene (PCE), trichloroethene (TCE),cisdichloroethene (cis-DCE) andtransdichloroethene (trans-DCE) in environmental biotreatment studies using gas chromatography coupled with a solid phase mi...

203

Headspace solid-phase Microextraction of Volatile and furanic Compounds in Coated Fish Sticks: Effect of the Extraction Temperature  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work evaluated the effect of temperature on headspace solid-phase microextraction of volatile and furanic compounds in coated fish sticks. The major goal was the analysis of the samples as consumed, to reproduce volatile compounds people feel when consuming those products. Extraction at 37 ºC (the human body temperature) throughout the HS-SPME analysis of volatile and furanic compounds in coated fish was compared with higher extraction temperatures, which are freque...

Pe?rez-palacios, M. T.; Petisca, Catarina; Pinho, Oli?via; Ferreira, I. M. P. L. V. O.

2012-01-01

204

Synthesis and application of surface-imprinted activated carbon sorbent for solid-phase extraction and determination of copper (II)  

Science.gov (United States)

A new Cu(II)-imprinted amino-functionalized activated carbon sorbent was prepared by a surface imprinting technique for selective solid-phase extraction (SPE) of Cu(II) prior to its determination by inductively coupled plasma atomic emission spectrometry (ICP-AES). Experimental conditions for effective adsorption of Cu(II) were optimized with respect to different experimental parameters using static and dynamic procedures in detail. Compared with non-imprinted sorbent, the ion-imprinted sorbent had higher selectivity and adsorption capacity for Cu(II). The maximum static adsorption capacity of the ion-imprinted and non-imprinted sorbent for Cu(II) was 26.71 and 6.86 mg g-1, respectively. The relatively selectivity factor values (?r) of Cu(II)/Zn(II), Cu(II)/Ni(II), Cu(II)/Co(II) and Cu(II)/Pb(II) were 166.16, 50.77, 72.26 and 175.77, respectively, which were greater than 1. Complete elution of the adsorbed Cu(II) from Cu(II)-imprinted sorbent was carried out using 2 mL of 0.1 mol L-1 EDTA solution. The relative standard deviation of the method was 2.4% for eleven replicate determinations. The method was validated for the analysis by two certified reference materials (GBW 08301, GBW 08303), the results obtained is in good agreement with standard values. The developed method was also successfully applied to the determination of trace copper in natural water samples with satisfactory results.

Li, Zhenhua; Li, Jingwen; Wang, Yanbin; Wei, Yajun

2014-01-01

205

Multi-walled carbon nanotube modified dummy-template magnetic molecularly imprinted microspheres as solid-phase extraction material for the determination of polychlorinated biphenyls in fish.  

Science.gov (United States)

Novel multi-walled carbon nanotube modified dummy-template molecularly imprinted microspheres (MWCNTs@DMMIPs) were successfully synthesized as adsorbents for six kinds of polychlorinated biphenyls (PCBs). MWCNTs@DMMIPs were prepared by a surface molecular imprinting technique. Core-shell Fe3 O4 @SiO2 nanoparticles were employed as magnetic support. 3,4-Dichlorobenzene acetic acid was used as a dummy template instead of PCBs, methacrylic acid was used as functional monomer and ethylene glycol dimethacrylate was used as the cross-linker. The resulting absorbent was characterized by various methods. The adsorbent was employed for extracting PCBs and exhibited good selectivity and high adsorption efficiency. Furthermore, it was reusable and capable of magnetic separation. Adsorption kinetics fit well with a pseudo-second-order kinetic equation and also exhibited a three-stage intra-particle diffusion model. The Freundlich model was used to describe the adsorption isotherms. The materials were successfully applied to the magnetic dispersive solid-phase extraction of six kinds of PCBs followed by gas chromatography with mass spectrometry determination in fish samples, the limit of detection of six kinds of PCBs were 0.0028-0.0068 ?g/L and spiked recoveries ranged between 73.41 and 114.21%. The prepared adsorbent was expected to be a new material for the removal and recovery of PCBs from contaminated foods. PMID:24737691

Du, Xiaowen; Lin, Saichai; Gan, Ning; Chen, Xidong; Cao, Yuting; Li, Tianhua; Zhan, Pan

2014-07-01

206

Methods of Imazethapyr Extraction from Soil and Cleaning up by Solid Phase Extraction  

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Full Text Available The aim of this work was to optimize the determination methods of imazethapyr residues in soil using HPLC with DAD and C 18 (Hypersil ODS, 5 ?m, 2.0 x 250 mm columns and to find the most appropiate solvent for imazethapyr extraction as well as the most suitable SPE cartridges for extract purification. For soil extract purification we decided to use SPE Amino/Carbon, C 18 and SDB-1 cartridges. On the basis of the perfomed chromatography method for optimising imazethapyrdetermination in soil it was found that the most appropiate method for determining imazethapyr residues in soil is the extraction method with Na2CO3 solution, followed by cleaning up on SPE SDB-1 catridge and elution with ACN and water.

Sanja Lazi?

2007-01-01

207

CLEANUP OF ENVIRONMENTAL SAMPLE EXTRACTS USING FLORISIL SOLID-PHASE EXTRACTION CARTRIDGES  

Science.gov (United States)

Disposable cartridges containing 1 g of Florisil are investigated for cleanup of extracts obtained from various environmental natrices. lution patterns and recoveries are determined for 22 chlorinated hydrocarbons and 16 phthalate esters in the presence of interferents such as co...

208

Colorimetric Solid Phase Extraction (CSPE): Using Color to Monitor Spacecraft Water Quality  

Science.gov (United States)

In August 2009, an experimental water quality monitoring kit based on Colorimetric Solid Phase Extraction (CSPE) technology was delivered to the International Space Station (ISS). The kit, called the Colorimetric Water Quality Monitoring Kit (CWQMK), was launched as a Station Development Test Objective (SDTO) experiment to evaluate the suitability of CSPE technology for routine use monitoring water quality on the ISS. CSPE is a sorption-spectrophotometric technique that combines colorimetric reagents, solid-phase extraction, and diffuse reflectance spectroscopy to quantify trace analytes in water samples. In CSPE, a known volume of sample is metered through a membrane disk that has been impregnated with an analyte-specific colorimetric reagent and any additives required to optimize the formation of the analyte-reagent complex. As the sample flows through the membrane disk, the target analyte is selectively extracted, concentrated, and complexed. Formation of the analyte-reagent complex causes a detectable change in the color of the membrane disk that is proportional to the amount of analyte present in the sample. The analyte is then quantified by measuring the color of the membrane disk surface using a hand-held diffuse reflectance spectrophotometer (DRS). The CWQMK provides the capability to measure the ionic silver (Ag +) and molecular iodine (I2) in water samples on-orbit. These analytes were selected for the evaluation of CSPE technology because they are the biocides used in the potable water storage and distribution systems on the ISS. Biocides are added to the potable water systems on spacecraft to inhibit microbial growth. On the United States (US) segment of the ISS molecular iodine serves as the biocide, while the Russian space agency utilizes silver as a biocide in their systems. In both cases, the biocides must be maintained at a level sufficient to control bacterial growth, but low enough to avoid any negative effects on crew health. For example, the presence of high levels of iodine in water can cause taste and odor issues that result in decreased water consumption by the crew. There are also concerns about potential impacts on thyroid function following exposure to high levels of iodine. With silver, there is a risk of developing argyria, an irreversible blue-gray discoloration of the skin, associated with long term consumption of water containing high concentrations of silver. The need to ensure that safe, effective levels of biocide are maintained in the potable water systems on the ISS provides a perfect platform for evaluating the suitability of CSPE technology for in-flight water quality monitoring. This paper provides an overview of CSPE technology and details on the silver and iodine methods used in the CWQMK. It also reports results obtained during in-flight analyses performed with the CWQMK and briefly discusses other potential applications for CSPE technology in both the spacecraft and terrestrial environments.

Gazda, Daniel B.; Nolan, Daniel J.; Rutz, Jeffrey A.; Schultz, John R.; Siperko, Lorraine M.; Porter, Marc D.; Lipert, Robert J.; Flint, Stephanie M.; McCoy, J. Torin

2010-01-01

209

Novel sol-gel hybrid methyltrimethoxysilane-tetraethoxysilane as solid phase extraction sorbent for organophosphorus pesticides.  

Science.gov (United States)

A novel sol-gel hybrid methyltrimethoxysilane-tetraethoxysilane (MTMOS-TEOS) was produced and applied as sorbent for solid phase extraction (SPE). Five selected organophosphorus pesticides (OPPs) were employed as model compounds to evaluate the extraction performance of the synthesized sol-gel organic-inorganic hybrid MTMOS-TEOS. Analysis was performed using gas chromatography-mass spectrometry. Several important SPE parameters were optimized. Under the optimum extraction conditions, the method using the sol-gel organic-inorganic hybrid MTMOS-TEOS as SPE sorbent showed good linearity in the range of 0.001-1 ?g L(-1), good repeatability (RSD 2.1-3.1%, n=5), low limits of detection at S/N=3 (0.5-0.9 pg mL(-1)) and limit of quantification (1-3 pg mL(-1), S/N=10). The performance of the MTMOS-TEOS SPE was compared to commercial C18 Supelclean SPE since C18 SPE is widely used for OPPs. The MTMOS-TEOS SPE method LOD was 500-600 × lower than the LOD of commercial C18 SPE. The LOD achieved with the sol-gel organic-inorganic hybrid MTMOS-TEOS SPE sorbent allowed the detection of these OPPs in drinking water well below the level set by European Union (EU) at 0.1 ?g L(-1) of each pesticides. The developed MTMOS-TEOS SPE method was successfully applied to real sample analysis of the selected OPPs from several water samples and its application extended to the analysis of several fruits samples. Excellent recoveries and RSDs of the OPPs were obtained from the various water samples (recoveries: 97-111%, RSDs 0.4-2.8%, n=3) and fruit samples (recoveries: 96-111%), RSDs 1-4%, n=5) using the sol-gel organic-inorganic hybrid MTMOS-TEOS SPE sorbent. Recoveries and RSDs of OPPs from river water samples and fruit samples using C18 Supelclean SPE sorbent were 91-97%, RSD 0.9-2.6, n=3 and 86-96%, RSD 3-8%, n=5, respectively). The novel sol-gel hybrid MTMOS-TEOS SPE sorbent demonstrate the potential as an alternative inexpensive extraction sorbent for OPPs with higher sensitivity for the OPPs. PMID:22326188

Wan Ibrahim, Wan Aini; Veloo, Krishna Veni; Sanagi, Mohd Marsin

2012-03-16

210

/ Volatile composition of peppermint (Mentha piperita L.) commercial teas through solid phase extraction  

Scientific Electronic Library Online (English)

Full Text Available SciELO Venezuela | Language: Spanish Abstract in spanish Estudo da composição da fração volátil do extrato aquoso de sachês de hortelã pimenta (Mentha piperita L.) através da extração em fase sólida. O princípio desse trabalho foi investigar a fração volátil do extrato aquoso de sachês comerciais de hortelã pimenta usando cromatografia gasosa com detector [...] es de ionização em chama e de massas. As amostras foram preparadas em condições similares às usadas para o preparo do chá caseiro. Os compostos voláteis foram isolados via método de extração em fase sólida com adsorvente Porapak Q e eluídos com acetona. Uma estimativa dos valores médios dos ácidos carboxílicos de cadeias média e curta ficou na faixa de 50-64 ?g kg-1, enquanto alcoóis alifáticos e hidrocarbonetos acíclicos tiveram valores menores do que 6 ?g kg-1. Os terpenos (275-382 ?g kg-1) foram os compostos majoritários alcançando 89 % dos sólidos totais. Um total de 16 compostos voláteis, entre eles, dodecano, acetoína, acetol, citral, geraniol e ácido octanóico foram descritos pela primeira vez no chá de hortelã pimenta. Esses resultados poderiam ser atribuídos aos diferentes métodos analíticos empregados, principalmente devido ao uso de diferentes técnicas de extração e pré-concentração. Em função da proporção menor de terpenos no extrato aquoso é razoável especular que as propriedades químicas do óleo essencial da hortelã pimenta não sejam totalmente reproduzidas com o consumo do chá caseiro. Abstract in english Volatiles from aqueous extract of peppermint commercial sachets were investigated through gas chromatography/flame ionization detection (GC/FID) and GC/mass spectrometry (MS). Samples were prepared under similar conditions as in homemade tea. Volatiles were isolated using solid phase extraction meth [...] od (SPE) with Porapak Q trap followed by desorption with acetone. Estimated mean values for short and medium chain carboxylic acids (C2- C12) and ketones lay in the range of 50-64 ?g kg-1 whilst aliphatic alcohols and acyclic hydrocarbons had values lower than 6 ?g kg-1. The major volatiles were terpenes (275-382 ?g kg-1) that reached 89 % of the total composition. A total of 16 compounds, among them dodecane, acetoin, acetol, citral, geraniol and octanoic acid have been described by the first time in peppermint tea. These findings could be attributed to the different analytical approach employed, mainly to the use of different extraction/pre-concentration techniques. Given the apparently lower proportion of terpenes in the aqueous extract it may be that the chemical properties of the peppermint essential oil are not entirely reproduced with homemade tea.

L.G, Riachi; I.E., Abi-Zaid; R.F.A, Moreira; C.A.B., De Maria.

211

/ Volatile composition of peppermint (Mentha piperita L.) commercial teas through solid phase extraction  

Scientific Electronic Library Online (English)

Full Text Available SciELO Venezuela | Language: Spanish Abstract in spanish Estudo da composição da fração volátil do extrato aquoso de sachês de hortelã pimenta (Mentha piperita L.) através da extração em fase sólida. O princípio desse trabalho foi investigar a fração volátil do extrato aquoso de sachês comerciais de hortelã pimenta usando cromatografia gasosa com detector [...] es de ionização em chama e de massas. As amostras foram preparadas em condições similares às usadas para o preparo do chá caseiro. Os compostos voláteis foram isolados via método de extração em fase sólida com adsorvente Porapak Q e eluídos com acetona. Uma estimativa dos valores médios dos ácidos carboxílicos de cadeias média e curta ficou na faixa de 50-64 ?g kg-1, enquanto alcoóis alifáticos e hidrocarbonetos acíclicos tiveram valores menores do que 6 ?g kg-1. Os terpenos (275-382 ?g kg-1) foram os compostos majoritários alcançando 89 % dos sólidos totais. Um total de 16 compostos voláteis, entre eles, dodecano, acetoína, acetol, citral, geraniol e ácido octanóico foram descritos pela primeira vez no chá de hortelã pimenta. Esses resultados poderiam ser atribuídos aos diferentes métodos analíticos empregados, principalmente devido ao uso de diferentes técnicas de extração e pré-concentração. Em função da proporção menor de terpenos no extrato aquoso é razoável especular que as propriedades químicas do óleo essencial da hortelã pimenta não sejam totalmente reproduzidas com o consumo do chá caseiro. Abstract in english Volatiles from aqueous extract of peppermint commercial sachets were investigated through gas chromatography/flame ionization detection (GC/FID) and GC/mass spectrometry (MS). Samples were prepared under similar conditions as in homemade tea. Volatiles were isolated using solid phase extraction meth [...] od (SPE) with Porapak Q trap followed by desorption with acetone. Estimated mean values for short and medium chain carboxylic acids (C2- C12) and ketones lay in the range of 50-64 ?g kg-1 whilst aliphatic alcohols and acyclic hydrocarbons had values lower than 6 ?g kg-1. The major volatiles were terpenes (275-382 ?g kg-1) that reached 89 % of the total composition. A total of 16 compounds, among them dodecane, acetoin, acetol, citral, geraniol and octanoic acid have been described by the first time in peppermint tea. These findings could be attributed to the different analytical approach employed, mainly to the use of different extraction/pre-concentration techniques. Given the apparently lower proportion of terpenes in the aqueous extract it may be that the chemical properties of the peppermint essential oil are not entirely reproduced with homemade tea.

L.G, Riachi; I.E., Abi-Zaid; R.F.A, Moreira; C.A.B., De Maria.

2012-12-01

212

Fabrication of metal-organic frameworks and graphite oxide hybrid composites for solid-phase extraction and preconcentration of luteolin.  

Science.gov (United States)

A novel solid-phase extraction sorbent, metal-organic frameworks and graphite oxide hybrid composite, was prepared by a solvothermal technique. The morphology and properties of the resultant material were examined by Fourier transform infrared spectroscopy, X-ray diffraction and field emission scanning electron microscopy. To evaluate the extraction performance of the resultant sorbent, luteolin was chosen as a model analyte. The extraction conditions were optimized. Based on these, a convenient and efficient solid-phase extraction procedure for the determination of luteolin was established and the subsequent quantification step was performed by square wave anodic stripping voltammetry. Under the optimal conditions, the oxidation current increased linearly with increasing the concentration of luteolin in the range of 5.0 × 10(-9)-5.0 × 10(-7)molL(-1) with a correlation coefficient of 0.9983 and a detection limit of 7.9 × 10(-10)molL(-1). The relative standard deviation of seven successive scans was 4.20% for 5.0 × 10(-8)molL(-1) luteolin. This work not only proposes a useful method for sample pretreatment, but also reveals the great potential of metal-organic frameworks based hybrid materials as an excellent sorbent in solid-phase extraction. PMID:24720967

Wang, Yang; Wu, Yichun; Ge, Huali; Chen, Huanhuan; Ye, Guiqin; Hu, Xiaoya

2014-05-01

213

State-of-the-art in solid-phase extraction of biofluids (M10)  

International Nuclear Information System (INIS)

Full text: A major drawback of many SPE protocols in bioanalytical LC is a rather unselective and/or time consuming clean-up procedure. In order to optimize SPE based sample processing with regard to selectivity and speed we investigated tailor-made SPE adorbents, distinct SPE column hardware as well as a novel software (ChromSword ADS, Merck KGaA) for LC(MS)-integrated SPE using column-switching. Restricted Access Materials (RAM) are one family of such special SPE column packing. RAMs are characterized in that they have a defined size-selective exclusion barrier and a non-adsorptive outer particle surface towards macromolecular matrix components (e.g. proteins, nucleic acids, polysaccharides). Low-molecular compounds (e.g. drugs) have free access to the binding centers and thus can be extracted and enriched prior to their analytical separation and MS detection. A RAM-SPE column (e.g. LiChrospher ADS, Merck KGaA, Germany) allows the direct, multiple injection and fractionation of crude, complex samples such as hemolyzed blood, plasma, serum, milk, saliva, urine, fermentation broth and cell-culture or tissue homogenate supernatant. In order to improve the selectivity, we extended this on-line sample clean-up protocol by coupling a reversed-phase modified RAM-SPE column with a second short column packed with a Molecularly Imprinted Polymeric (MIP) adsorbent. MIP-SPE adsorbents can be compared with immunoaffinity adsorbents. Besides selective/specific molecular recognition properties, these artificial antibodies exhibit a high stability with respect to pressure, pH, temperature as well as organic solvents. These innovative adsorbents are also attractive because of the ease, low-cost and high reproducibility of preparation. Using MIPS in combination with RAMs we developed a generic SPE platform and protocol, respectively, for highly selective clean-up of complex (bio)fluids. Finally, we succeeded in speeding up the RAM fractionation step (e.g. extraction of 50 pl of human plasma in less than 60 seconds) by applying an optimized column size and flow-rate, respectively. In conclusion, tailor-made SPE-column packing and hardware allow a robust and rugged operation of on-line (high speed) SPE-(LC)-MS(MS). Refs. 6 (author)

214

Solid-phase extraction of antioxidant compounds from commercial cranberry extract and its antiradical activity  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study is concerned with the fractionation and determination of major antioxidant compounds (phenols, flavonoids, anthocyanins and vitamin C) in commercial cranberry extract. The total content of phenolics, flavonoids and total and monomers of anthocyanins, determined spectrophotometrically, was 1.67 mg/g, 0.41 mg/g, 5.12 mg/g and 3.32 mg/g. The content of vitamin C, determined volumetrically, was 121.74 mg/g. Commercial cranberry extract was dissolved in 80 % acetone and the solution was...

Tumbas Vesna T.; ?ilas Sonja M.; ?anadanovi?-Brunet Jasna M.; ?etkovi? Gordana S.; Savatovi? Sla?ana M.

2007-01-01

215

Dispersive micro solid-phase extraction for the rapid analysis of synthetic polycyclic musks using thermal desorption gas chromatography-mass spectrometry.  

Science.gov (United States)

A simple and solvent-free method for the rapid analysis of five synthetic polycyclic musks in water samples is described. The method involves the use of dispersive micro solid-phase extraction (D-?-SPE) coupled with direct thermal desorption (TD) gas chromatography-mass spectrometry (GC-MS) operating in the selected-ion-storage (SIS) mode. The parameters affecting the extraction efficiency of the target analytes from water sample and the thermal desorption conditions in the GC injection-port were optimized using a central composite design method. The optimal extraction conditions involved immersing 3.2mg of a typical octadecyl (C18) bonded silica adsorbent (i.e., ENVI-18) in a 10mL water sample. After extraction by vigorously shaking for 1.0min, the adsorbents were collected and dried on a filter. The adsorbents were transferred to a micro-vial, which was directly inserted into GC temperature-programmed injector, and the extracted target analytes were then thermally desorbed in the GC injection-port at 337°C for 3.8min. The limits of quantitation (LOQs) were determined to be 1.2-3.0ng/L. Precision, as indicated by relative standard deviations (RSDs), was less than 9% for both intra- and inter-day analysis. Accuracy, expressed as the mean extraction recovery, was between 74 and 90%. A preliminary analysis of the river water samples revealed that galaxolide (HHCB) and tonalide (AHTN) were the two most common synthetic polycyclic musks present. Using a standard addition method, their concentrations were determined to in the range from 11 to 140ng/L. PMID:23932027

Chung, Wu-Hsun; Tzing, Shin-Hwa; Ding, Wang-Hsien

2013-09-13

216

EVALUATION OF SAMPLE EXTRACT CLEANUP USING SOLID-PHASE EXTRACTION CARTRIDGES  

Science.gov (United States)

Fractionation and cleanup of sample extracts prior to instrumental analysis is usually accomplished by column chromatography, gel permeation chromatography, or acid-base partitioning. n this report, the results of a study are described in which we investigated the application of ...

217

Simultaneous quantification of dissolved organic carbon fractions and copper complexation using solid-phase extraction  

International Nuclear Information System (INIS)

Trace metal cycling in natural waters is highly influenced by the amount and type of dissolved organic C (DOC). Although determining individual species of DOC is unrealistic, there has been success in classifying DOC by determining operationally defined fractions. However, current fractionation schemes do not allow for the simultaneous quantification of associated trace metals. Using operational classifications, a scheme was developed to fractionate DOC based on a set of seven solid-phase extraction (SPE) cartridges. The cartridges isolated fractions based on a range of specific mechanisms thought to be responsible for DOC aggregation in solution, as well as molecular weight. The method was evaluated to determine if it can identify differences in DOC characteristics, including differences in Cu-DOC complexation. Results are that: (1) cartridge blanks were low for both DOC and Cu, (2) differences are observed in the distribution of DOC amongst the fractions from various sources that are consistent with what is known about the DOC materials and the mechanisms operative for each cartridge, (3) when present as a free cation, Cu was not retained by non-cationic cartridges allowing the method to be used to assess Cu binding, (4) the capability of the method to provide quantitative assessment of Cu-DOC complexation was demonstrated for a variety of DOC standards, (5) Cu was found to preferentially bind with high molecular weight fractions of DOC, and (6) estimated partitioning coefficients and conditional binding constants for Cu were similar to those reported elsewhere. The method developed describes DOC characteristics based on specific bonding mechanisms (hydrogen, donor-acceptor, London dispersion, and ionic bonding) while simultaneously quantifying Cu-DOC complexation. The method provides researchers a means of describing not only the extent of DOC complexation but also how that complex will be behave in natural waters.

218

Determination of Scopolamine in Human Saliva Using Solid Phase Extraction and LC/MS/MS  

Science.gov (United States)

Purpose: Scopolamine is the preferred treatment for motion sickness during space flight because of its quick onset of action, short half-life and favorable side-effect profile. The dose administered depends on the mode of administration and usually ranges between 0.1 and 0.8 mg. Such small doses make it difficult to detect concentrations of scopolamine in biological fluids by using conventional HPLC methods. To measure scopolamine in saliva and thereby to evaluate the pharmacokinetics of scopolamine, we developed an LC/MS/MS method using off-line solid phase extraction. Method: Samples (0.5mL) were loaded onto Waters Oasis HLB co-polymer cartridges (10 mg, 1 mL) and eluted with 0.5 mL methanol without evaporation and reconstitution. HPLC separation of the eluted sample was performed using an Agilent Zorbax SB-CN column (50 x 2.1 mm) at a flow rate of 0.2 mL/min for 4 minutes. The mobile phase for separation was 90:10 (v/v) methanol: ammonium acetate (2 mM) in water, pH 5.0 +/- 0.1. Concentrations of scopolamine were determined using a Micromass Quattro Micro(TM) mass spectrometer with electrospray ionization (ESI). ESI mass spectra were acquired in positive ion mode with multiple reaction monitoring for the determination of scopolamine m/z = 304.2 yields 138.1 and internal standard (IS) hyoscyamine m/z = 290.2 yields 124.1. Results: The method is rapid, reproducible, specific and has the following parameters: scopolamine and the IS are eluted at 1.7 and 3.2 min respectively. The linear range is 50-5000 pg/mL for scopolamine in saliva with correlation coefficients > 0.99 with a CV MS/MS detector.

Wang, Zuwei; Vaksman, Zalman; Boyd, Jason; Putcha, Lakshmi

2007-01-01

219

Matrix supported tailored polymer for solid phase extraction of fluoride from variety of aqueous streams  

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer Th complexed with poly (bis[2-(methacryloyloxy)-ethyl]phosphate) as tailored polymer membranes. Black-Right-Pointing-Pointer Membranes offered high capacity and selectivity for fluoride in aqueous media. Black-Right-Pointing-Pointer Quantitative uptake (80 {+-} 5%) of fluoride. Black-Right-Pointing-Pointer Fast sorption kinetics. Black-Right-Pointing-Pointer Reusability of polymer membranes. - Abstract: Fluoride related health hazards (fluorosis) are a major environmental problem in many regions of the world. It affects teeth; skeleton and its accumulation over a long period can lead to changes in the DNA structure. It is thus absolutely essential to bring down the fluoride levels to acceptable limits. Here, we present a new inorganic-organic hybrid polymer sorbent having tailored fixed-sites for fluoride sorption. The matrix supported poly (bis[2-(methacryloyloxy)-ethyl]phosphate) was prepared by photo-initiator induced graft-polymerization in fibrous and microporous (sheet) host poly(propylene) substrates. These substrates were conditioned for selective fluoride sorption by forming thorium complex with phosphate groups on bis[2-methacryloyloxy)-ethyl] phosphate (MEP). These tailored sorbents were studied for their selectivity towards fluoride in aqueous media having different chemical conditions. The fibrous sorbent was found to take up fluoride with a faster rate (15 min for Almost-Equal-To 76% sorption) than the sheet sorbent. But, the fluoride loading capacity of sheet sorbent (4320 mg kg{sup -1}), was higher than fibrous and any other sorbent reported in the literature so far. The sorbent developed in the present work was found to be reusable after desorption of fluoride using NaOH solution. It was tested for solid phase extraction of fluoride from natural water samples.

Thakur, Neha; Kumar, Sanjukta A.; Wagh, D.N. [Analytical Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Das, Sadananda; Pandey, Ashok K. [Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Kumar, Sangita D., E-mail: sangdk@barc.gov.in [Analytical Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Reddy, A.V.R. [Analytical Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

2012-01-30

220

Utilizing ion-pairing hydrophilic interaction chromatography solid phase extraction for efficient glycopeptide enrichment in glycoproteomics  

DEFF Research Database (Denmark)

Glycopeptide enrichment is a prerequisite to enable structural characterization of protein glycosylation in glycoproteomics. Here we present an improved method for glycopeptide enrichment based on zwitter-ionic hydrophilic interaction chromatography solid phase extraction (ZIC-HILIC SPE) in a microcolumn format. The method involves TFA ion pairing (IP) to increase the hydrophilicity difference between glycopeptides and nonglycosylated peptides. Three mobile phases were investigated, i.e., 2% formic acid (defined as IP(2% FA) ZIC-HILIC SPE), 0.1% TFA and 1% TFA (defined as IP(0.1% TFA) and IP(1% TFA) ZIC-HILIC SPE) all containing 80% acetonitrile. Samples of increasing complexities, i.e., digests of single glycoproteins, a five-glycoprotein mixture, and depleted plasma, were used in the study. The presence of TFA in the mobile phase significantly improved the glycopeptide enrichment for all complexities, as evaluated by enhanced glycopeptide detection using MALDI-TOF MS and RP-LC-ESI-MS/MS, e.g., the glycopeptide ion signals were increased by up to 3.7-fold compared to IP(2% FA) conditions. The enhanced glycopeptide detection was promoted by a substantial depletion of nonglycosylated peptides, offering an almost complete isolation of IgG glycopeptides using a single SPE enrichment step and a reduction from 711 nonglycosylated peptides observed in the IP(2% FA) ZIC-HILIC SPE retained plasma fraction, to only 157 and 97 when 0.1% and 1% TFA was used in the mobile phase. In conclusion, this systematic study has shown that TFA-containing mobile phases increase glycopeptide enrichment efficiency considerably for a broad range of sample complexities when using ZIC-HILIC SPE.

Mysling, Simon; Palmisano, Giuseppe

2010-01-01

 
 
 
 
221

Elemental analysis of iron and steel by solid-phase extraction/ICP-MS using a cation exchange extraction disk  

International Nuclear Information System (INIS)

A simple pretreating method which consists of solid phase extraction using cation exchange extraction disk was tried for the determination of trace elements in iron and steel samples by means of inductively coupled plasma mass spectrometry (ICP-MS). The sample of 0.100 g was dissolved by nitric acid, subsequently adding 8 cm3 of 10 w/v% ethylenediaminetetraacetic acid disodium salt (EDTA) solution as masking agent for the iron matrix. The sample solution was adjusted by the dilution with water to pH 1.8 or more and poured into the extraction disk. The target elements retained in the extraction disk were then eluted using 10 cm3 of 3 kmol/m3 nitric acid. Quantities of the obtained target elements were determined using ICP-MS. Highly sensitive quantification was established for 6 trace elements in iron and steel, and for Ca, Mn, Mg, Ba, Tl and Sr with the following detection limits [3?; ng/g (ppb)]: Ca: 4.75, Mn: 0.26, Mg: 0.40, Ba: 0.014, Tl: 0.033 and Sr: 0.11. This method is extremely easy, is rapid, the amount of the reagent used is a little, and a free skill and the zero emission are achieved. (author)

222

Elemental analysis of iron and steel by solid-phase extraction/ICP-MS using a high performance extraction disk  

International Nuclear Information System (INIS)

A simple pretreating method which consists of solid phase extraction using cation exchange extraction disk was tried for the determination of trace elements in iron and steel samples by means of inductively coupled plasma mass spectrometry (ICP-MS). The sample of 0.100 g was dissolved by nitric acid, hydrofluoric acid and hydrogen peroxide. The sample solution was adjusted by the dilution with water to pH 2.3 or more and poured into the extraction disk. The target elements retained in the extraction disk were then eluted using 10 cm3 of 3 kmol/m3 nitric acid. Quantities of the obtained target elements were determined using ICP-MS. Highly sensitive quantification was established for 8 trace elements in iron and steel, and for Al, Ca, Mn, Mg, Ba, Cd, Zn and Sr with the following detection limit [3 ?; ng/g (ppb)]: Al: 0.48, Ca: 8.54, Mn: 0.09, Mg: 0.10, Ba: 0.13, Cd: 0.11, Zn: 0.21 and Sr: 0.07. This method is extremely easy, is rapid, the amount of the reagent used is a little, and a skill free and the zero emission are achieved. (author)

223

Simultaneous spectrophotometric determination of trace amount of polycyclic aromatic hydrocarbons in water samples after magnetic solid-phase extraction by using projection pursuit regression.  

Science.gov (United States)

Magnetic solid-phase extraction based on coated nano-magnets Fe(3)O(4) was applied for the preconcentration of four polycyclic aromatic hydrocarbons (PAHs; anthracene, phenanthrene, fluorine, and pyrene) in environmental water samples prior to simultaneous spectrophotometric determination using multivariate calibration method. Magnetic nanoparticles, carrying target metals, were easily separated from the aqueous solution by applying an external magnetic field so, no filtration or centrifugation was necessary. After elution of the adsorbed PAHs, the concentration of PAHs was determined spectrophotometrically with the aid of a new and efficient multivariate spectral analysis base on principal component analysis-projection pursuit regression, without separation of analytes. The obtained results revealed that using projection pursuit regression as a flexible modeling approach improves the predictive quality of the developed models compared with partial least squares and least squares support vector machine methods. The method was used to determine four PAHs in environmental water samples. PMID:22684809

Ghasemi, Jahan B; Zolfonoun, E

2013-03-01

224

Extraction of crocin from saffron (Crocus sativus) using molecularly imprinted polymer solid-phase extraction.  

Science.gov (United States)

A new molecularly imprinted polymer for extraction of crocin from saffron stigmas was prepared using gentiobiose (a glycoside moiety in crocin structure) as a template. Crocin binding to gentiobiose imprinted polymer (Gent-MIP) was studied in comparison with a blank nonimprinted polymer in aqueous media. Affinity of the Gent-MIP for the crocin was more than the nonimprinted polymer at all concentrations. In Scatchard analysis, the number of binding sites in each gram of polymer (maximum binding sites) and dissociation constant of crocin to binding sites were 18.4 micromol/g polymer and 11.2 microM, respectively. The Gent-MIP was then used as the sorbent in an SPE method for isolation and purification of crocin from methanolic extract of saffron stigmas. The recovery of crocin, safranal and picrocrocin was determined in washing and elution steps. The Gent-MIP had significantly higher affinity for crocin than other compounds and enabled selective extraction of crocin with a high recovery (84%) from a complex mixture. The results demonstrated the possibility of using a part of a big molecule in preparing a molecularly imprinted polymer with a good selectivity for the main structure. PMID:20589782

Mohajeri, Seyed Ahmad; Hosseinzadeh, Hossein; Keyhanfar, Fariborz; Aghamohammadian, Javad

2010-08-01

225

Chromium speciation by solid phase extraction on Dowex M 4195 chelating resin and determination by atomic absorption spectrometry.  

Science.gov (United States)

A solid phase extraction procedure has been established for chromium speciation in natural water samples prior to determination by atomic absorption spectrometry. The procedure is based on the solid phase extraction of the Cr(VI)- Dowex M 4195 chelating resin. After oxidation of Cr(III) to Cr(VI) by using H2O2, the presented method was applied to the determination of the total chromium. The level of Cr(III) is calculated by difference of total chromium and Cr(VI) levels. The procedure was optimized for some analytical parameters including pH, eluent type, flow rates of sample and eluent, matrix effects, etc. The presented method was applied for the speciation of chromium in natural water samples with satisfactory results (recoveries >95%, RSDs GBW 07603 Bush branched and leaves. PMID:17951001

Saygi, Kadriye Ozlem; Tuzen, Mustafa; Soylak, Mustafa; Elci, Latif

2008-05-30

226

Chromium speciation by solid phase extraction on Dowex M 4195 chelating resin and determination by atomic absorption spectrometry  

International Nuclear Information System (INIS)

A solid phase extraction procedure has been established for chromium speciation in natural water samples prior to determination by atomic absorption spectrometry. The procedure is based on the solid phase extraction of the Cr(VI)- Dowex M 4195 chelating resin. After oxidation of Cr(III) to Cr(VI) by using H2O2, the presented method was applied to the determination of the total chromium. The level of Cr(III) is calculated by difference of total chromium and Cr(VI) levels. The procedure was optimized for some analytical parameters including pH, eluent type, flow rates of sample and eluent, matrix effects, etc. The presented method was applied for the speciation of chromium in natural water samples with satisfactory results (recoveries >95%, RSDs <10%). In the determinations of chromium species, flame atomic absorption spectrometer was used. The results were checked by using NIST SRM 2711 Montana soil and GBW 07603 Bush branched and leaves

227

Selective solid-phase extraction using molecular imprinted polymer sorbent for the analysis of florfenicol in food samples.  

Science.gov (United States)

A molecularly imprinted polymer (MIP) for the selective solid phase extraction (SPE) of florfenicol (FF) was prepared using FF as template and 4-vinyl pyridine (4-VP) as functional monomer. For comparison, non-imprinted polymer (NIP) was synthesized in the absence of FF. The synthesized polymers were characterised by infrared spectroscopy (IR), scanning electron microscopy (SEM), thermogravimetry analysis (TGA) and differential thermal analysis (DTA). A molecularly imprinted solid phase extraction (MISPE) procedure was performed in column method by spectrophotometry detection technique. The prepared FF-MIP showed higher adsorption capacity than the non-imprinted polymer (NIP) and the maximum static adsorption capacities of FF on the MIP and the NIP were 4.32 and 2.88mgg(-1), respectively. Kinetics of the adsorption was fast and the adsorption equilibrium was achieved in 30min. The accuracy of the developed method was satisfactory for determination of FF in fish, chicken meat and honey samples. PMID:23790909

Sadeghi, Susan; Jahani, Moslem

2013-11-15

228

A novel dispersive micro solid phase extraction using zein nanoparticles as the sorbent combined with headspace solid phase micro-extraction to determine chlorophenols in water and honey samples by GC-ECD.  

Science.gov (United States)

This study presents a new technique, dispersive micro solid phase extraction (DMSPE) combined with headspace solid phase micro-extraction (HS-SPME) for extraction and determination of chlorophenols (CPs) in water and honey samples using a Gas Chromatography-Electron Capture Detector (GC-ECD). Zein nanoparticles were made by liquid-liquid dispersion and applied for the first time as the sorbent phase in DMSPE. In the proposed DMSPE-HS-SPME method, 1% w/v of ethanolic zein solution was added to an aqueous sample and then a dose of the in-situ generated zein nanoparticles was applied to a pre-concentration of target analytes. Thermal desorption of analytes was performed after the isolating sorbent phase, and then HS-SPME was applied for enrichment prior to introducing to gas chromatography. All the important parameters influencing efficiency of the extraction process such effects of salt, pH, sorbent concentration, temperature, sorbent solution volume in DMSPE procedure, extraction temperature, extraction time, desorption temperature and time in the HS-SPME procedure were investigated and optimized. Results showed that under optimum extraction conditions, detection limits (signal to noise ratio=3) were in the range of 0.08-0.6 ng mL(-1) and evaluations for relative standard deviations (RSDs %) were between 6.62% and 8.36%. PMID:25059191

Farhadi, Khalil; Matin, Amir Abbas; Amanzadeh, Hatam; Biparva, Pourya; Tajik, Hossein; Farshid, Amir Abbas; Pirkharrati, Hossein

2014-10-01

229

Flame atomic absorption spectrometric determination of trace amounts of heavy metal ions after solid phase extraction using modified sodium dodecyl sulfate coated on alumina  

International Nuclear Information System (INIS)

A sensitive and selective solid phase extraction procedure for the determination of traces of Cu(II), Zn(II), Pb(II) and Fe(III) has been developed. An alumina-sodium dodecyl sulfate (SDS) coated on with meso-phenyl bis(indolyl) methane (MPBIM) was used for preconcentration and determination of Cu(II), Zn(II), Pb(II) and Fe(III) ions by flame atomic absorption spectrometry. The analyte ions were adsorbed quantitatively on adsorbent due to their complexation with MPBIM. Adsorbed metals were quantitatively eluted using 6 mL of 4 mol L-1 nitric acid. The effects of parameters such as pH, amount of alumina, amount of MBITP, flow rate, type and concentration of eluting agent were examined. The effects of interfering ions on the separation-preconcentration of analytes were also investigated. The relative standard deviation of the method was found to be less than 3.0%. The presented procedure was successfully applied for determination of analytes in real samples

230

Flame atomic absorption spectrometric determination of trace amounts of heavy metal ions after solid phase extraction using modified sodium dodecyl sulfate coated on alumina  

Energy Technology Data Exchange (ETDEWEB)

A sensitive and selective solid phase extraction procedure for the determination of traces of Cu(II), Zn(II), Pb(II) and Fe(III) has been developed. An alumina-sodium dodecyl sulfate (SDS) coated on with meso-phenyl bis(indolyl) methane (MPBIM) was used for preconcentration and determination of Cu(II), Zn(II), Pb(II) and Fe(III) ions by flame atomic absorption spectrometry. The analyte ions were adsorbed quantitatively on adsorbent due to their complexation with MPBIM. Adsorbed metals were quantitatively eluted using 6 mL of 4 mol L{sup -1} nitric acid. The effects of parameters such as pH, amount of alumina, amount of MBITP, flow rate, type and concentration of eluting agent were examined. The effects of interfering ions on the separation-preconcentration of analytes were also investigated. The relative standard deviation of the method was found to be less than 3.0%. The presented procedure was successfully applied for determination of analytes in real samples.

Ghaedi, Mehrorang [Chemistry Department, Yasouj University, Yasouj 75914-353 (Iran, Islamic Republic of)], E-mail: m_ghaedi@mail.yu.ac.ir; Niknam, Khodabakhsh [Chemistry Department, Persian Gulf University, Bushehr (Iran, Islamic Republic of); Shokrollahi, Ardeshir; Niknam, Ebrahim; Rajabi, Hamid Reza [Chemistry Department, Yasouj University, Yasouj 75914-353 (Iran, Islamic Republic of); Soylak, Mustafa [Chemistry Department, University of Erciyes, 38039 Kayseri (Turkey)

2008-06-30

231

A Nanoparticle-based Solid Phase Extraction Method for Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometric Analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A solid-phase extraction (SPE) procedure with the use of superparamagnetic Fe3O4 nanoparticles as extracting agent was developed for HPLC-ESI-MS/MS analysis. Four most heavily used triazine pesticides (herbicides) were taken as the test compounds. The NPs showed an excellent capability to retain the compounds tested, and a quantitative extraction was achieved within 10 min under the testing conditions, i.e. 100 ?L NP solution was added to 400 mL sample in a beaker with stirring. After extrac...

Song, Yaru; Zhao, Shulin; Tchounwou, Paul; Liu, Yi-ming

2007-01-01

232

Investigating the Retention Mechanisms of Liquid Chromatography Using Solid-Phase Extraction Cartridges  

Science.gov (United States)

Liquid chromatography (LC) experiments for the undergraduate analytical laboratory course often illustrate the application of reversed-phase LC to solve a separation problem, but rarely compare LC retention mechanisms. In addition, a high-performance liquid chromatography instrument may be beyond what some small colleges can purchase. Solid-phase

O'Donnell, Mary E.; Musial, Beata A.; Bretz, Stacey Lowery; Danielson, Neil D.; Ca, Diep

2009-01-01

233

Rapid determination of cyclamate in foods by solid-phase extraction and capillary electrophoresis.  

Science.gov (United States)

A method for the determination of cyclamate in food was developed using solid-phase extraction (SPE) and capillary electrophoresis (CE) with indirect ultraviolet (UV) detection. A 5-10 g sample in 0.1 mol/L hydrochloric acid was homogenized and made up to a volume of 50 mL with 0.1 mol/L hydrochloric acid. After the sample was centrifuged, 25 mL of supernatant was loaded into an Oasis HLB SPE cartridge. The cartridge was washed with 2 mL of demineralized water followed by 2 mL of 50% aqueous methanol, and cyclamate was eluted with 4.5 mL of 50% aqueous methanol. The eluate was added to a solution of sodium propionate (internal standard) for CE analysis. The cyclamate in the eluate was electrophoresed on a fused-silica capillary using 1 mmol/L hexadecyltrimethylammonium bromide and 10 mmol/L potassium sorbate as a running buffer. Detection and reference wavelengths of cyclamate determined with a UV detector were 300 and 254 nm, respectively. The calibration curves for cyclamate showed good linearity in the range of 2-1000 microg/mL and the limits of detection in beverage, fruit in syrup, jam, pickles and confectionary are sample dependent and ranged from 5-10 microg/g. The recovery of cyclamate added at a level of 200 microg/g to various kinds of foods was 93.3-108.3% and the relative standard deviation was less than 4.9% (n=3). A number of commercial samples were analyzed using the proposed method. Cyclamate was detected in one waume, two pickles, and two sunflower seeds. The quantitative values determined with CE correlated to those from high-performance liquid chromatography (HPLC) (the detected values of cyclamate in a sunflower seed measured by CE and HPLC were 3.40 g/kg and 3.51 g/kg, respectively). This analytical method for cyclamate using CE is especially suitable for use in the field. PMID:17433340

Horie, Masao; Ishikawa, Fusako; Oishi, Mitsuo; Shindo, Tetsuya; Yasui, Akiko; Ito, Koichi

2007-06-22

234

Molecularly imprinted solid-phase extraction for selective extraction of bisphenol analogues in beverages and canned food.  

Science.gov (United States)

This study aimed to develop a selective analytical method for the simultaneous determination of seven bisphenol analogues in beverage and canned food samples by using a new molecularly imprinted polymer (MIP) as a sorbent for solid-phase extraction (SPE). Liquid chromatography coupled to triple-quadruple tandem mass spectrometry (LC-MS/MS) was used to identify and quantify the target analytes. The MIP-SPE method exhibited a higher level of selectivity and purification than the traditional SPE method. The developed procedures were further validated in terms of accuracy, precision, and sensitivity. The obtained recoveries varied from 50% to 103% at three fortification levels and yielded a relative standard deviation (RSD, %) of less than 15% for all of the analytes. The limits of quantification (LOQ) for the seven analytes varied from 0.002 to 0.15 ng/mL for beverage samples and from 0.03 to 1.5 ng/g for canned food samples. This method was used to analyze real samples that were collected from a supermarket in Beijing. Overall, the results revealed that bisphenol A and bisphenol F were the most frequently detected bisphenols in the beverage and canned food samples and that their concentrations were closely associated with the type of packaging material. This study provides an alternative method of traditional SPE extraction for screening bisphenol analogues in food matrices. PMID:25350221

Yang, Yunjia; Yu, Jianlong; Yin, Jie; Shao, Bing; Zhang, Jing

2014-11-19

235

Development and validation of an automated solid-phase extraction and liquid chromatographic method for determination of lumefantrine in capillary blood on sampling paper.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A bioanalytical method for the determination of lumefantrine in 100 microl blood applied onto sampling paper, by solid-phase extraction and liquid chromatography, has been developed and validated. Whatman 31 ET Chr sampling paper was pre-treated with 0.75 M tartaric acid before sampling capillary blood to enable a high recovery of lumefantrine. Lumefantrine was extracted from the sampling paper, then further purified using solid-phase extraction and finally quantified with HPLC. The between-d...

Blessborn, D.; Ro?msing, S.; Annerberg, A.; Sundquist, D.; Bjo?rkman, A.; Lindegardh, N.; Bergqvist, Y.

2007-01-01

236

Evaluation of Superparamagnetic Silica Nanoparticles for Extraction of Triazines in Magnetic in-Tube Solid Phase Microextraction Coupled to Capillary Liquid Chromatography  

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Full Text Available The use of magnetic nanomaterials for analytical applications has increased in the recent years. In particular, magnetic nanomaterials have shown great potential as adsorbent phase in several extraction procedures due to the significant advantages over the conventional methods. In the present work, the influence of magnetic forces over the extraction efficiency of triazines using superparamagnetic silica nanoparticles (NPs in magnetic in tube solid phase microextraction (Magnetic-IT-SPME coupled to CapLC has been evaluated. Atrazine, terbutylazine and simazine has been selected as target analytes. The superparamagnetic silica nanomaterial (SiO2-Fe3O4 deposited onto the surface of a capillary column gave rise to a magnetic extraction phase for IT-SPME that provided a enhancemment of the extraction efficiency for triazines. This improvement is based on two phenomena, the superparamegnetic behavior of Fe3O4 NPs and the diamagnetic repulsions that take place in a microfluidic device such a capillary column. A systematic study of analytes adsorption and desorption was conducted as function of the magnetic field and the relationship with triazines magnetic susceptibility. The positive influence of magnetism on the extraction procedure was demonstrated. The analytical characteristics of the optimized procedure were established and the method was applied to the determination of the target analytes in water samples with satisfactory results. When coupling Magnetic-IT-SPME with CapLC, improved adsorption efficiencies (60%–63% were achieved compared with conventional adsorption materials (0.8%–3%.

R. A. González-Fuenzalida

2014-04-01

237

A fast, simple and green method for the extraction of carbamate pesticides from rice by microwave assisted steam extraction coupled with solid phase extraction.  

Science.gov (United States)

This paper presented a fast, simple and green sample pretreatment method for the extraction of 8 carbamate pesticides in rice. The carbamate pesticides were extracted by microwave assisted water steam extraction method, and the extract obtained was immediately applied on a C18 solid phase extraction cartridge for clean-up and concentration. The eluate containing target compounds was finally analysed by high performance liquid chromatography with mass spectrometry. The parameters affecting extraction efficiency were investigated and optimised. The limits of detection ranging from 1.1 to 4.2ngg(-1) were obtained. The recoveries of 8 carbamate pesticides ranged from 66% to 117% at three spiked levels, and the inter- and intra-day relative standard deviation values were less than 9.1%. Compared with traditional methods, the proposed method cost less extraction time and organic solvent. PMID:24054230

Song, Weitao; Zhang, Yiqun; Li, Guijie; Chen, Haiyan; Wang, Hui; Zhao, Qi; He, Dong; Zhao, Chun; Ding, Lan

2014-01-15

238

Solid-phase extraction of plutonium in various oxidation states from simulated groundwater using N-benzoylphenylhydroxylamine  

International Nuclear Information System (INIS)

Solid-phase extraction of plutonium in different individual and mixed oxidation states from simulated groundwater (pH 8.5) was studied. The extraction of plutonium species was carried out in a dynamic mode using DIAPAK C16 cartridges modified by N-benzoylphenylhydroxylamine (BPHA). It was shown that the extent of recovery depends on the oxidation state of plutonium. The extraction of Pu(IV) was at the level of 98-99% regardless of the volume and flow-rate of the sample solution. Pu(V) was extracted by 90-95% and 75-80% from 10- and 100-mL aliquots of the samples, respectively, whereas the extraction of Pu(VI) did not exceed 45-50%. An equimolar mixture of Pu(IV), Pu(V), and Pu(VI) was extracted by 74%. The distribution coefficients (Kd) and kinetic exchange capacities (S) of plutonium in various oxidation states were measured. It was found that during the sorption process, Pu(V) was reduced to Pu(IV) by 80-90% after an hour-long contact with the solid phase. Pu(VI) is reduced to Pu(V) by 34% and to Pu(IV) by 55%. In the case of mixed-valent solution of plutonium, only Pu(V) and Pu(IV) were found in the effluents. (author)

239

Synthesis and Evaluation of a Molecularly Imprinted Polymer for Selective Solid-Phase Extraction of Irinotecan from Human Serum Samples  

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Full Text Available A molecularly imprinted polymer (MIP was synthesized by non-covalent imprinting polymerization using irinotecan as template. Methacrylic acid and 4-vinylpyridine were selected as functional monomers. An optimized procedure coupled to LC-PDA analysis was developed for the selective solid-phase extraction of irinotecan from various organic media. A specific capacity of 0.65 µmol•g?1 for the MIP was determined. The high specificity of this MIP was demonstrated by studying the retention behaviour of two related compounds, camptothecin and SN-38. This support was applied for the extraction of irinotecan from human serum samples.

Isabelle Lefebvre-Tournier

2012-02-01

240

Magnetic solid phase extraction based on magnetite/reduced graphene oxide nanoparticles for determination of trace isocarbophos residues in different matrices.  

Science.gov (United States)

A simple one-step solvothermal method was applied for the preparation of magnetite/reduced graphene oxide (MRGO), and the synthetic nanocomposites with a magnetic particle size of ?8nm were used as an adsorbent for magnetic solid phase extraction of isocarbophos (ICP) in different sample matrices prior to gas chromatography (GC) detection. The identity of the nanomaterial was confirmed using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. It was shown that Fe3O4 nanoparticles with a uniform size were homogeneously anchored on RGO nanosheets. Increased oxidation degrees of graphite oxide, big particle sizes and large loading amounts of Fe3O4 on the surface of RGO led to a decrease of adsorption capacity of MRGO to ICP. The adsorption behavior of this adsorbent was better fitted by the pseudo-second-order kinetic model. Several parameters affecting the extraction efficiency were investigated and optimized, including adsorbent dosage, extraction time, ionic strength and desorption conditions. And then, a rapid and effective method based on MRGO combined with GC was developed for the determination of ICP in aqueous samples. A linear range from 0.05 to 50ngmL(-1) was obtained with a high correlation coefficient (R(2)) of 0.9995, and the limit of detection was found to be 0.0044ngmL(-1). This method was successfully applied to the analysis of ICP in five kinds of samples, including apple, rice, lake water, cowpea and cabbage. The recoveries in different sample matrices were in the range from 81.00% to 108.51% with relative standard deviations less than 9.72%. It can be concluded that the proposed analytical method is highly-efficient, sensitive, precise, accurate and practicable. PMID:24800969

Yan, Shan; Qi, Ting-Ting; Chen, De-Wen; Li, Zhao; Li, Xiu-Juan; Pan, Si-Yi

2014-06-20

 
 
 
 
241

Preparation of molecular imprinted polymers using bi-functional monomer and bi-crosslinker for solid-phase extraction of rutin.  

Science.gov (United States)

Molecular imprinted polymers (MIPs) were prepared using rutin as the template, different reagents as the functional monomer and different reagents as the cross-linker by solution polymerization. Several parameters that would influence the performance of MIPs were investigated including the type of functional monomer (single or double) and cross-linker (single or double), and the molar ratio of the template, the functional monomer and the cross-linker. The optimum synthesis conditions of MIPs were found to be bi-monomers (acrylamide-co-2-vinyl pyridine, 3:1) and bi-crosslinker (ethylene glycol dimethacrylate-co-divinylbenzene, 3:1). The ratio of the template, the functional monomer and the cross-linker was found to be 1:6:20. MIPs synthesized under these conditions were filled into the cartridges as the adsorbents of solid-phase extraction (SPE). A competition test was conducted to authenticate the selectivity and the specificity of molecularly imprinted solid-phase extraction (MISPE) for rutin using the mixture solution of standard rutin and its structural analogs including quercetin, naringenin and kaempferol. Compared with purchased SPE including C(18), silica and PCX, MISPE showed better selectivity and enrichment property for rutin in the extracted solutions of Chinese medicinal plants than any others. The mean recoveries were 85.93% (RSD: 3.04%, n=3) for Saururus chinensis (Lour.) Bail and 88.61% (RSD: 3.36%, n=3) for Flos Sophorae, respectively, which indicated that the optimized rutin-MIPs possess the value of practical application. PMID:22483895

Zeng, Huan; Wang, Yuzhi; Liu, Xiaojie; Kong, Jinhuan; Nie, Chan

2012-05-15

242

Rotating disk sorptive extraction of Cu-bisdiethyldithiocarbamate complex from water and its application to solid phase spectrophotometric quantification.  

Science.gov (United States)

This study demonstrates the first use of polydimethylsiloxane (PDMS) immobilized on a rotating disk for the extraction of copper from aqueous matrices and its subsequent direct determination by solid phase UV-Visible spectrophotometry. To accomplish the solid-phase extraction and the direct solvent-free spectrophotometric measurement, sodium diethyldithiocarbamate (NaDDTC) was used as an analytical reagent to form the uncharged chromophore complex Cu(DDTC)2, which absorbs at 432 nm. Different physicochemical conditions (pH, temperature, reagent concentration, chemical modifiers) and hydrodynamic factors (rotation velocity, extraction time, sample volume) were optimized. Under the optimized conditions, extraction equilibrium times of 30, 53 and 90 min were obtained for 100, 500 and 1000 mL of sample, respectively, with preconcentration factors of 286, 712 and 1284, respectively. The methodology was precise (repeatability and reproducibility of 7.2 and 8.4%, respectively, as relative standard deviation) and accurate (recovery of 96.7%) when analyzing a multielement certified reference standard. The latter study also confirmed the high selectivity of the extraction and determination of the copper chromophore over other metal ions. The obtained limits of detection and quantification reached values lower than 12 ?g L(-1), which can be reduced further by increasing the sample volume. Accuracy was also assessed using both recovery tests on drinking water matrices (95.5% recovery) and comparison with results obtained by an independent method using inductively coupled plasma-optical emission spectroscopy (ICP-OES); no significant differences were observed. PMID:24813962

Muñoz, Carlos; Toral, M Inés; Ahumada, Inés; Richter, Pablo

2014-01-01

243

Comparison of liquid-liquid extraction-thin layer chromatography with solid-phase extraction-high-performance thin layer chromatography in detection of urinary morphine  

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Liquid-liquid extraction-thin layer chromatography (LLE-TLC) has been a common and routine combined method for detection of drugs in biological materials. Solid-phase extraction (SPE) is gradually replacing the traditional LLE method. High performance thin layer chromatography (HPTLC) has several advantages over TLC. The present work studied the higher efficiency of a new SPE-HPTLC method over that of a routine LLE-TLC method, in extraction and detection of urinary morphine. Fifty-eight urine...

Ahadi, Ali; Partoazar, Alireza; Abedi-khorasgani, Mohammad-hassan; Shetab-boushehri, Seyed Vahid

2011-01-01

244

Comparison of liquid-liquid extraction and solid phase extraction for manganese in water analysed by neutron activation analysis  

International Nuclear Information System (INIS)

Full text: The concentrations of total manganese in most natural water systems are in the range of 0.001 to 1.0 mgl-1. The maximum contaminant level (MCL) of manganese in drinking water as recommended by US Environmental Protection Agency (EPA) is 0.05 mg/l. Analytical methods capable of measuring the low level of manganese are necessary for evaluating the quality of natural water. Neutron activation analysis (NAA) is one of the most sensitive techniques for the determination of trace elements. However, direct application of neutron activation for analysis of trace elements in a complex system such as natural waters is generally difficult because of matrix interference. Preconcentration and/or matrix separation procedures are often required before irradiation to eliminate such interferences. In this study two methods based on solid phase extraction (SPE) and liquid-liquid extraction (LLE) has been developed for the extraction of manganese in water prior to irradiation. Experimental parameters such as effect of pH, type and volume of the chelating agent and flow rate were studied and optimized. Analytical parameters such as linearity, precision, accuracy, detection and quantitation limits, and matrix effects for SPE and LLE methods were evaluated for comparison purposes with the aim of selecting the most appropriate depending on the high recoveries and lower detection capabilities required. Both methods can be applied to real samples and give the same results, but SPE allows the high recovery of 99.8 % of manganese with lower detection limit of 0.001 ?gl-1 as compared to LLE (90.5 % of manganese recovery with lower detection limit of 0.73 ?gl-1). Furthermore, the SPE is easily used compared with LLE and not time consuming which allows analysis of a large number of samples. (author)

245

Comparison of liquid-liquid extraction and solid phase extraction for manganese in water analyzed by neutron activation analysis  

International Nuclear Information System (INIS)

Full text: The concentrations of total manganese in most natural water systems are in the range of 0.001 to 1.0 mgl-1. The maximum contaminant level (MCL) of manganese in drinking water as recommended by US Environmental Protection Agency (EPA) is 0.05 mg/l. Analytical methods capable of measuring the low level of manganese are necessary for evaluating the quality of natural water. Neutron activation analysis (NAA) is one of the most sensitive techniques for the determination of trace elements. However, direct application of neutron activation for analysis of trace elements in a complex system such as natural waters is generally difficult because of matrix interference. Preconcentration and/or matrix separation procedures are often required before irradiation to eliminate such interferences. In this study two methods based on solid phase extraction (SPE) and liquid-liquid extraction (LLE) has been developed for the extraction of manganese in water prior to irradiation. Experimental parameters such as effect of pH, type and volume of the chelating agent and flow rate were studied and optimized. Analytical parameters such as linearity, precision, accuracy, detection and quantitation limits, and matrix effects for SPE and LLE methods were evaluated for comparison purposes with the aim of selecting the most appropriate depending on the high recoveries and lower detection capabilities required. Both methods can be applied to real samples and give the same results, but SPE allows the high recovery of 99.8% of manganese with lower detection limit of 0.001 ?gl-1 as compared to LLE (90.5% of manganese recovery with lower detection limit of 0.73 ?gl-1). Furthermore, the SPE is easily used compared with LLE and not time consuming which allows analysis of a large number of samples. (author)

246

Spectrophotometric Determination of Aluminium in Iron Ores Using Solid-Phase Extraction  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese No presente trabalho, um procedimento para separação e determinação de alumínio em matrizes de ferro é proposto. Este é baseado na extração em fase sólida do ferro sob a forma de tiocianatos complexos, pela espuma de poliuretano. Os seguintes parâmetros foram estudados: efeito de pH e da concentraçã [...] o de tiocianato sob a extração do ferro, tempo de agitação necessário para extração quantitativa, quantidade de espuma requerida, separação de alumínio de ferro e de outros elementos, influência de ânions sob a sorção de ferro pela espuma e características analíticas do procedimento para determinação de alumínio usando o azul de metiltimol (MTB) como reagente cromogênico. Os resultados demonstraram que na faixa de pH de 1,5 a 4,7, com tiocianato na concentração de 0.80 mol L-1, tempo de agitação de 1 min e usando 1 g de espuma de poliuretano para extração, é possível separar alumínio(40 mig) de: grandes quantidades de ferro (10 mg), 800 mig de cobre(II), cobalto(II), zinco(II), mercúrio(II), manganês(II), estanho(IV) e tungstênio(V); 100 mig de chumbo(II) e titânio(IV) e 50 mig de vanádio(V). Cálcio(II), bário(II), estrôncio(II) e magnésio(II) não são separados por este processo; entretanto, não reagem com o MTB nas condições estabelecidas para determinação de alumínio. Os ânions nitrato, cloreto, sulfato e acetato não afetam a extração do ferro. Fosfato e EDTA devem estar ausentes. O azul de metiltimol possibilita a determinação espectrofotométrica de alumínio, com absortividade molar de 1,32 x 10(4) L mol-1 cm-1(em 528 nm), sensibilidade de calibração de 0,491 mL mig-1, limite de detecção de 5 ng mL-1, intervalo dinâmico de aplicação de 15 ng mL-1 a 1,00 mig mL-1 e coeficiente de variação de 0,73%. O procedimento proposto foi aplicado para determinação de alumínio em padrões de minérios de ferro e ligas metálicas. Os resultados encontrados não exibiram diferenças significativas em relação aos valores certificados. Abstract in english In the present paper, a procedure for separation and determination of aluminium in iron matrices is proposed. It is based on the solid-phase extraction of the iron, in the form of thiocyanate complexes, by a polyurethane(PU) foam. The followings parameters were studied: effect of pH and of the thioc [...] yanate concentration on the iron extraction, shaking time required for quantitative extraction, amount of PU foam necessary for complete extraction of iron, aluminium separation from other cations, influence of anions on the iron sorption by PU foam and analytical characteristics of the procedure for aluminium determination using methylthymol blue as chromogenic reagent. The results show that, in the pH range from 1.5 to 4.7, with a thiocyanate concentration of 0.80 mol L-1, by extraction using 1 g of polyurethane foam and a shaking time of 1 min, aluminium (40 mug) can be separated from large amounts of iron (10 mg), 800 mug of copper(II), cobalt(II), zinc(II), mercury(II), tin(IV), manganese(II) and tungsten(V); 100 mug of titanium(IV) and lead(II); and 50 mug of vanadium(V). Calcium(II), barium(II), strontium(II) and magnesium(II) can not be separated by this process, but do not react with MTB under the conditions used for aluminium determination. The anions nitrate, chloride, sulfate and acetate do not affect the iron extraction. Phosphate and EDTA must be absent. The methylthymol blue allowed the spectrophotometric determination of aluminium with molar absorptivity of 1.32 x 10(4) L mol-1 cm-1 (528 nm), calibration sensitivity of 0.491 mL g-1, detection limit of 5 ng mL-1 and dynamic interval of application of 15 ng mL-1 to 1.00 mg mL-1 and variation coefficient of 0.73%. The proposed procedure was applied for aluminium determination in iron ores and metal-base alloy standards. The obtained results did not show significant difference from the certified values.

Sérgio Luis Costa, Ferreira; Valfredo Azevedo, Lemos; Antônio Celso Spinola, Costa; Djane Santiago de, Jesus; Marcelo Souza de, Carvalho.

247

Spectrophotometric Determination of Aluminium in Iron Ores Using Solid-Phase Extraction  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese No presente trabalho, um procedimento para separação e determinação de alumínio em matrizes de ferro é proposto. Este é baseado na extração em fase sólida do ferro sob a forma de tiocianatos complexos, pela espuma de poliuretano. Os seguintes parâmetros foram estudados: efeito de pH e da concentraçã [...] o de tiocianato sob a extração do ferro, tempo de agitação necessário para extração quantitativa, quantidade de espuma requerida, separação de alumínio de ferro e de outros elementos, influência de ânions sob a sorção de ferro pela espuma e características analíticas do procedimento para determinação de alumínio usando o azul de metiltimol (MTB) como reagente cromogênico. Os resultados demonstraram que na faixa de pH de 1,5 a 4,7, com tiocianato na concentração de 0.80 mol L-1, tempo de agitação de 1 min e usando 1 g de espuma de poliuretano para extração, é possível separar alumínio(40 mig) de: grandes quantidades de ferro (10 mg), 800 mig de cobre(II), cobalto(II), zinco(II), mercúrio(II), manganês(II), estanho(IV) e tungstênio(V); 100 mig de chumbo(II) e titânio(IV) e 50 mig de vanádio(V). Cálcio(II), bário(II), estrôncio(II) e magnésio(II) não são separados por este processo; entretanto, não reagem com o MTB nas condições estabelecidas para determinação de alumínio. Os ânions nitrato, cloreto, sulfato e acetato não afetam a extração do ferro. Fosfato e EDTA devem estar ausentes. O azul de metiltimol possibilita a determinação espectrofotométrica de alumínio, com absortividade molar de 1,32 x 10(4) L mol-1 cm-1(em 528 nm), sensibilidade de calibração de 0,491 mL mig-1, limite de detecção de 5 ng mL-1, intervalo dinâmico de aplicação de 15 ng mL-1 a 1,00 mig mL-1 e coeficiente de variação de 0,73%. O procedimento proposto foi aplicado para determinação de alumínio em padrões de minérios de ferro e ligas metálicas. Os resultados encontrados não exibiram diferenças significativas em relação aos valores certificados. Abstract in english In the present paper, a procedure for separation and determination of aluminium in iron matrices is proposed. It is based on the solid-phase extraction of the iron, in the form of thiocyanate complexes, by a polyurethane(PU) foam. The followings parameters were studied: effect of pH and of the thioc [...] yanate concentration on the iron extraction, shaking time required for quantitative extraction, amount of PU foam necessary for complete extraction of iron, aluminium separation from other cations, influence of anions on the iron sorption by PU foam and analytical characteristics of the procedure for aluminium determination using methylthymol blue as chromogenic reagent. The results show that, in the pH range from 1.5 to 4.7, with a thiocyanate concentration of 0.80 mol L-1, by extraction using 1 g of polyurethane foam and a shaking time of 1 min, aluminium (40 mug) can be separated from large amounts of iron (10 mg), 800 mug of copper(II), cobalt(II), zinc(II), mercury(II), tin(IV), manganese(II) and tungsten(V); 100 mug of titanium(IV) and lead(II); and 50 mug of vanadium(V). Calcium(II), barium(II), strontium(II) and magnesium(II) can not be separated by this process, but do not react with MTB under the conditions used for aluminium determination. The anions nitrate, chloride, sulfate and acetate do not affect the iron extraction. Phosphate and EDTA must be absent. The methylthymol blue allowed the spectrophotometric determination of aluminium with molar absorptivity of 1.32 x 10(4) L mol-1 cm-1 (528 nm), calibration sensitivity of 0.491 mL g-1, detection limit of 5 ng mL-1 and dynamic interval of application of 15 ng mL-1 to 1.00 mg mL-1 and variation coefficient of 0.73%. The proposed procedure was applied for aluminium determination in iron ores and metal-base alloy standards. The obtained results did not show significant difference from the certified values.

Sérgio Luis Costa, Ferreira; Valfredo Azevedo, Lemos; Antônio Celso Spinola, Costa; Djane Santiago de, Jesus; Marcelo Souza de, Carvalho.

1998-04-01

248

Extração em fase sólida (SPE e micro extração em fase sólida (SPME de piretróides em água Solid-phase extraction (SPE and solid-phase microextraction of pyrethroids in water  

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Full Text Available The pyrethroids bifenthrin, permethrin, cypermethrin and deltamethrin were extracted by solid phase extraction (SPE and solid phase microextraction (SPME. The analysis were performed on a gas chromatograph with electron capture detection (GC-ECD. Octadecil Silano-C18, Florisil and Silica stationary phases were studied for SPE. Better results were obtained for Florisil which gave recoveries from 80% to 108%. Pyrethroids extraction by SPME showed a linear response and a detection limit of 10 pg ml-1. Although the data showed that the two extraction methods were able to isolate the pesticide residues from water samples, the best results were obtained by using SPME which is more sensitive, faster, cheeper, being a more useful technique for the analysis of pyrethroids in drinking water.

Wilma Regina Barrionuevo

2001-04-01

249

Determination of hyperoside and isoquercitrin in rat plasma by membrane-protected micro-solid-phase extraction with high-performance liquid chromatography.  

Science.gov (United States)

A novel method, micro-solid-phase extraction based on membrane-protected molecularly imprinted polymer, was developed to extract hyperoside and isoquercitrin in rat plasma. Synthesized hyperoside MIPs were packed in a porous polyether sulfone membrane envelope to perform extraction. The parameters sorbent materials, membrane types, extraction time and desorption conditions were optimized for micro-solid-phase extraction. Under the optimal conditions, correlation coefficients, 0.998 and 0.999, were obtained for hyperoside and isoquercitrin, respectively, with the linear range between 1 and 120??g/mL. The absolute extraction recoveries from 84.5 to 89.3% were found. The method detection limits of hyperoside and isoquercitrin were 0.24 and 0.22??g/mL, respectively. Compared with traditional methods, solid-phase extraction, liquid-liquid extraction and protein precipitation, the developed method was simple, highly efficient for extraction, environmentally friendly, and particularly suitable for complex biological samples. PMID:22258808

Yin, Xiao-Ying; Luo, Yong-Ming; Fu, Jian-Jiang; Zhong, You-Quan; Liu, Qing-Shan

2012-02-01

250

EPA Method 525.3 - Determination of Semivolatile Organic Chemicals in Drinking Water by Solid Phase Extraction and Capillary Column Gas Chromatography/Mass Spectrometry (GC/MS)  

Science.gov (United States)

Method 525.3 is an analytical method that uses solid phase extraction (SPE) and gas chromatography/mass spectrometry (GC/MS) for the identification and quantitation of 125 selected semi-volatile organic chemicals in drinking water. ...

251

Speciation analysis of thallium using solid phase extraction and electrothermal atomic absorption spectrometry  

International Nuclear Information System (INIS)

Complete text of publication follows. Thallium is a heavy, very toxic metallic element, which occurs in earth's crust in an estimated abundance from 0.1 to 0.8 mg.kg-1. In the environment, it is mainly combined with other elements (primarily oxygen, sulfur, halogens, potassium and rubidium) in inorganic compounds. During the weathering processes it can be mobilized by aqueous media and accumulated in sediments and soils. The main sources of pollution nowadays come from anthropogenic emissions from refineries, coal-fired power stations, mining activities, metal smelters and the cement industry. Thallium exists in natural waters as either Tl(I) (thallous) or Tl(III) (thallic) species. The oxidation state of Tl affects its complexation and subsequent bioavailability and toxicity in the environment. Thallium content in surface waters is within the range 1-82 ng l-1. Due to this low contents of Tl in water samples, it is necessary to combine the laboratory separation, preconcentration and determination techniques for the purpose of Tl speciation analysis. The scope of the presented work was to use an solid phase extraction (SPE) for the separation and preconcentration of Tl species in water samples followed by the determination using electrothermal atomic absorption spectrometry (ET AAS). In this method, Tl(III) was stabilized by formation of a Tl(III)-DTPA complex. Tl(I) species remained in its original form. These two species were then separated by These two species were then separated by using a cation exchange resin Amberlite IR120 and nitric acid as the eluent in a batch SPE protocol. The potential interferences of Fe (III), Al, Ca, Mg and other metals were investigated. The optimized experimental conditions for separation/preconcentration step (pH 2-3, time 15 min, temperature 60 deg C) and Zeeman ET AAS determination (chemical modifier Pd + ascorbic acid, atomization temperature 2100 deg C) were used for the speciation analysis of thallium in filtered acid water samples from open quartzite mine in the Banska Stiavnica - Sobov region (Slovakia) where an acid mine drainage is present mainly as a product of pyrite oxidation. For both Tl species the preconcentration factor about 40 was achieved, LOD and LOQ were 25 and 90 ng l-1, the calibration curve was linear from 75 ng l-1 to 25 ?g l-1, the precision expressed by a RSD ranged from 3 to 19%. The accuracy of analytical results was checked by the analyte addition technique and by analysis of water CRM samples. The work was supported by Slovak Research and Development Agency under the contracts No. LPP-0038-06, LPP-0188-06, SK-CZ-0044-07 and LPP-0146-09, by Scientific Grant Agency of Ministry of Education of Slovak Republic and the Slovak Academy of Sciences under the contracts No. VEGA 1/4463/07, VEGA 1/4464/07 and VEGA 1/0272/08 and by Ministry of Education, Youth and Sports of Czech Republic under the contract No. MEB 080813.

252

POLYELECTROLYTE MODIFIED SILICA GEL MICRO-COLUMN SOLID PHASE EXTRACTION FOR THE DETERMINATION OF SILVER IN ENVIRONMENTAL WATER SAMPLES BY FLAME ATOMIC ABSORPTION SPECTROMETRY  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english Silica gel was chemically modified with polyelectrolyte and used as a solid phase extraction adsorbent for the determination of trace silver in environmental water samples by flame absorption spectrometry (FAAS). The effects of pH, sample flow rate and volume, elution conditions and co-existing ions [...] on the recovery of the analyte were investigated. The results showed that silver could be adsorbed at pH 5.0 and eluted by 5.0 mL 2% thiourea in HNO3 (0.1 mol L-1). Under the optimized conditions, the adsorption capacity of modified silica gel was found to be 8.6 mg g-1 for silver. The detection limit of the proposed method was 1.0 ng mL-1 for silver with an enrichment factor of 18.7. The analytical result for the certified reference water sample (GBW08610) was in a good agreement with the certified value. The proposed method has also been successfully applied to the determination of trace silver in drinking water, well water, snow water and waste water with the recoveries for spiked samples between 94% and 105%.

GUOQIANG, XIANG; LULU, LI; XIUMING, JIANG; LIJUN, HE; LU, FAN.

253

POLYELECTROLYTE MODIFIED SILICA GEL MICRO-COLUMN SOLID PHASE EXTRACTION FOR THE DETERMINATION OF SILVER IN ENVIRONMENTAL WATER SAMPLES BY FLAME ATOMIC ABSORPTION SPECTROMETRY  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english Silica gel was chemically modified with polyelectrolyte and used as a solid phase extraction adsorbent for the determination of trace silver in environmental water samples by flame absorption spectrometry (FAAS). The effects of pH, sample flow rate and volume, elution conditions and co-existing ions [...] on the recovery of the analyte were investigated. The results showed that silver could be adsorbed at pH 5.0 and eluted by 5.0 mL 2% thiourea in HNO3 (0.1 mol L-1). Under the optimized conditions, the adsorption capacity of modified silica gel was found to be 8.6 mg g-1 for silver. The detection limit of the proposed method was 1.0 ng mL-1 for silver with an enrichment factor of 18.7. The analytical result for the certified reference water sample (GBW08610) was in a good agreement with the certified value. The proposed method has also been successfully applied to the determination of trace silver in drinking water, well water, snow water and waste water with the recoveries for spiked samples between 94% and 105%.

GUOQIANG, XIANG; LULU, LI; XIUMING, JIANG; LIJUN, HE; LU, FAN.

2182-21-01

254

Development and validation of an automated solid phase extraction and liquid chromatographic method for the determination of piperaquine in urine.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A sensitive and specific bioanalytical method for determination of piperaquine in urine by automated solid-phase extraction (SPE) and liquid chromatography (LC) has been developed and validated. Buffered urine samples (containing internal standard) were loaded onto mixed phase (cation-exchange and octylsilica) SPE columns using an ASPEC XL SPE robot. Chromatographic separation was achieved on a Chromolith Performance RP-18e (100 mm x 4.6 mm I.D.) LC column with phosphate buffer (pH 2.5; 0.1 m...

Tarning, J.; Singtoroj, T.; Annerberg, A.; Ashton, M.; Bergqvist, Y.; White, Nj; Day, Np; Lindegardh, N.

2006-01-01

255

HPLC method with UV detection for evaluation of digoxin tablet dissolution in acidic medium after solid-phase extraction.  

Science.gov (United States)

A simple and reliable method for the evaluation of dissolution of digoxin tablets in 0.01 M hydrochloric acid was developed. Digoxin and its degradation products after solid-phase extraction using C18 Sep-Pak cartridges were evaluated. Analyses were performed on C18 column (LiChrospher RP-18e, 5 microm, 125 x 4.0 mm), as mobile phase water and acetonitrile (72:28, v/v) were used. Detection wavelength was 218 nm. Identity of digoxin degradation products was confirmed by HPLC-MS. PMID:12946537

Jedlicka, A; Grafnetterová, T; Miller, V

2003-09-15

256

Quantification of endogenous brassinosteroids in sub-gram plant tissues by in-line matrix solid-phase dispersion-tandem solid phase extraction coupled with high performance liquid chromatography-tandem mass spectrometry.  

Science.gov (United States)

A matrix solid-phase dispersion (MSPD)-tandem mixed mode anion exchange (MAX)-mixed mode cation exchange (MCX) solid phase extraction-high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) method was developed for quantification of six endogenous brassinosteroids (BRs) (24-epibrassinolide, 24-epicastasterone, 6-deoxo-24-epicastasterone, dolichosterone, teasterone and typhasterol) in rice plant tissues. Non-polar interferences were removed effectively by C8 dispersant used in MSPD, while the following tandem MAX-MCX process facilitated the elimination of polar and ionizable compounds. The weak reversed-phase retention feature of MAX-MCX leaded to good compatibility of the elution solvents in the in-line coupled MSPD-MAX-MCX system. This system was optimized for extraction and purification of BRs in plant samples. The effects of the type of solid phase, the elution solvent, the extraction temperature and the clean-up material were studied. Before HPLC separation, BRs purified were derivatized by m-aminophenylboronic acid to enhance the sensitivity of MS/MS to BRs. Compared with traditional liquid-liquid extraction and solid phase extraction (LLE-SPE), the proposed MSPD-MAX-MCX method showed higher extraction efficiency, lower matrix effect, and advantages of easy manipulation and time-saving. The in-line MSPD-MAX-MCX coupled with HPLC-MS/MS method provided a linear response over two orders of magnitude of BRs concentration with correlation coefficients above 0.9982, limits of detection between 0.008 and 0.04ngmL(-1), relative standard deviations (RSDs) below 29.4%, and recoveries above 77.8%. The proposed method has been successfully applied to analysis of endogenous BRs in rice plant at booting stage and maturity stage. PMID:25092597

Wang, Lu; Duan, Chunfeng; Wu, Dapeng; Guan, Yafeng

2014-09-12

257

Selective solid-phase extraction of uranium by salicylideneimine-functionalized hydrothermal carbon  

International Nuclear Information System (INIS)

s was endothermic and spontaneous. Results from batch adsorption test in simulated nuclear industrial effluent, containing Cs+, Sr2+, Ba2+, Mn2+, Co2+, Ni2+, Zn2+, La3+, Ce3+, Nd3+, Sm3+, and Gd3+, showed the adsorbent could separate uranium(VI) from those competitive ions with high selectivity. The adsorbent might be promising for use in certain key steps in any future sustainable nuclear fuel cycle.

258

Molecularly imprinted solid phase extraction for the selective HPLC determination of alpha-tocopherol in bay leaves.  

Science.gov (United States)

A new sorbent for molecularly imprinted solid phase extraction (MISPE) was synthesized to extract and purify alpha-tocopherol (alpha-TP) from vegetable sources. Molecularly imprinted polymers (MIP) were synthesized using methacrylic acid (MAA) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as crosslinking agent using a photo-polymerization procedure. A thermo-polymerization was also performed but no imprinting effect in the resulting materials was raised. The proposed MISPE protocol could overcome the drawback of traditional detection methods, which require pre-treatments of the samples. The possibility to obtain the selective recognition of alpha-TP from natural samples in aqueous mixtures represents one of the main advantages of our materials. Our procedure involves the direct HPLC injection of eluate without any treatment and above all the use of no toxic and biocompatible organic solvents. After the evaluation of the selectivity of the alpha-TP imprinted polymers, the performance of these materials as solid phase extraction (SPE) sorbents was investigated. Our MISPE-HPLC procedure has a high sensitivity, LOD and LOQ were 3.49x10(-7) and 1.16x10(-6) mol L(-1), respectively, as well as good precision (intraday precision below 3.3% and interday precisions below 6.5%) and recovery (60%). Thus, it can be successfully used for the purification of alpha-TP from bay leaves. PMID:17543603

Puoci, F; Cirillo, G; Curcio, M; Iemma, F; Spizzirri, U G; Picci, N

2007-06-19

259

Separation and Enhanced Detection of Anesthetic Compounds Using Solid Phase Micro-Extraction (SPME)-Raman Spectroscopy.  

Science.gov (United States)

Polydimethylsiloxane (PDMS)-based solid-phase micro-extraction (SPME) was used along with Raman spectroscopy (RS) to separate and enhance the detection of five anesthetic compounds (halothane, propofol, isoflurane, enflurane, and etomidate) from aqueous and serum phases. Raman signals in the spectral ranges 250-450 cm(-1) and 950-1050 cm(-1) allowed the unique characterization of all five compounds when extracted into the PDMS phase. The SPME-RS detection of clinically relevant concentrations of aqueous propofol (6.5 ?M) and halothane (200 ?M) is shown. We quantify the partition coefficient for aqueous halothane in PDMS as log K = 1.9 ± 0.2. Solid-phase micro-extraction of the anesthetics makes their detection possible without the strong autofluorescent interference of serum proteins. Because of low solubility and/or weak Raman scattering, we found it challenging to detect enflurane, isoflurane, and etomidate directly from the aqueous phase, but could we do so with SPME enhancement. These studies show the potential of SPME-RS as a method for the direct detection of anesthetics in blood. PMID:25285420

Nwaneshiudu, Ikechukwu C; Nwaneshiudu, Chinwe A; Schwartz, Daniel T

2014-11-01

260

Analysis of Acidic Endogenous Phytohormones in Grapes by Using Online Solid-Phase Extraction Coupled with LC-MS/MS.  

Science.gov (United States)

Phytohormones play important roles in regulating numerous plant physiological and developmental processes, even during the postharvest storage period. In order to determine the functions and changes of gibberellins acid (GA3), indoleacetic acid (IAA), abscisic acid (ABA), indolebutyric acid (IBA) and jasmonic acid (JA) in grape berries during storage, an ultrasensitive method based on direct injection online solid-phase extraction coupled with high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed. Grape berries were extracted with cold methanol. After centrifugation, the supernatants were concentrated with a vacuum centrifugal concentrator and injected into an online solid-phase extraction column. After the cleanup procedure, the analytes were determined by LC-MS/MS. The results showed that the linearity of the proposed method was 10-210 µg kg(-1) for ABA, 20-200 µg kg(-1) for IBA, 15-320 µg kg(-1) for IAA, 20-320 µg kg(-1) for GA3 and 3.0-90.0 µg kg(-1) for JA. The limits of detection of the method were 0.71, 2.79, 0.94, 0.39 and 0.57 µg kg(-1), respectively. The proposed method was successfully applied to the analysis of endogenous phytohormones in grape berries during the postharvest storage period. PMID:24200641

Yu, Jian-Na; Meng, Qing-Yan; Liu, Wen-Jie; Lu, Ya-Ling; Ren, Xiao-Lin

2014-10-01

 
 
 
 
261

Supported liquid membrane-protected molecularly imprinted beads for micro-solid phase extraction of sulfonamides in environmental waters.  

Science.gov (United States)

In this work, molecularly imprinted polymer (MIP) beads have been prepared and evaluated for the development of a supported liquid membrane-protected micro-solid phase extraction method for the analysis of sulfonamides (SAs) in aqueous samples. The performance of MIP beads was firstly evaluated in cartridges by conventional solid-phase extraction for the simultaneous analysis of SAs. Afterward, beads were packed into a polypropylene hollow fiber protected by an organic solvent immobilized in the pores of the capillary wall. During the process, the analytes were extracted from the aqueous sample to the immobilized organic solvent and then selectively retained by the MIP beads located inside the capillary. The effect of various experimental parameters as sample pH, time and stirring-rate among others, were studied for the establishment of optimum rebinding conditions. Relative recoveries for all sulfonamides tested in river and reservoir water samples by the proposed method using 100mL water sample spiked with 50?g L-1 of each sulfonamide were within 70-120%, with a relative standard deviation (RSD) <10% (n=3). The detection limits (LODs) were within 0.2-3?gL(-1), depending upon the sulfonamide and the type of water used. PMID:24780262

Díaz-Álvarez, M; Barahona, F; Turiel, E; Martín-Esteban, A

2014-08-29

262

Solid-phase extraction and purification for the quantification of polycyclic aromatic hydrocarbon metabolites in fish bile  

Energy Technology Data Exchange (ETDEWEB)

An analytical protocol including solid-phase extraction and purification is described for the individual quantification of polycyclic aromatic hydrocarbon metabolites (hydroxylated PAHs) in liquid biological matrices such as plasma and bile. The method consists in an enzymatic deconjugation followed by a solid-phase extraction on a C{sub 18} cartridge and by a cleanup on an NH{sub 2} cartridge. Extracts are then submitted to a derivatization step before gas chromatography/mass spectrometry (GC/MS) analysis. The quantification of PAH metabolites is ensured by adding an internal standard, 1-hydroxypyrene deuterated, at the beginning of the protocol. Recoveries obtained for the entire protocol were for the major part of the compounds between 96 and 70%. However, recoveries were not so satisfying concerning 2-hydroxybiphenyl and especially 3-hydroxybenzo(a)pyrene, with 62 and 36% respectively. Finally, the protocol was applied to different fish bile samples and showed its good applicability to fish bile samples. The NH{sub 2} cleanup step has been proved to be a very selective purification step, necessary to remove most of the bile pigments before GC/MS injection. Different PAH metabolites could be detected in those natural samples and their quantification allowed us to distinguish different levels of fish exposure. (orig.)

Mazeas, Olivier; Budzinski, Helene [Universite Bordeaux I, Laboratoire de Physico-et Toxico-Chimie des Systemes Naturels, Talence (France)

2005-11-01

263

Analysis of volatiles in silver carp by headspace solid phase micro-extraction coupled with GC-MS  

International Nuclear Information System (INIS)

In this paper, a method for the determination of volatiles using headspace solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) was presented. The extraction conditions were optimized with reference to these volatiles as hexanal, heptanal, benzaldehyde, 1-Octen-3-ol, octanal, nonanal, decenal, 2,4-heptadienal and 2,4-decadienal. The extraction of fish muscle followed by incubation on a StableFlex divinyl benzene/Carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber during 50 in at 60 obtained the most effective extraction of the analytes. The methods by HS-SPME and GC-MS were effective in detecting volatiles in the gills, scales, viscera and fish muscles. The types of volatiles in the gill were more than other organs and the number of odors compounds was 63, and the number of volatiles in scales, viscera and fish muscles was 48, 44 and 42 respectively. (authors)

264

Explorative Solid-Phase Extraction (E-SPE) for Accelerated Microbial Natural Product Discovery, Dereplication, and Purification  

DEFF Research Database (Denmark)

Microbial natural products (NP) cover a high chemical diversity, and in consequence extracts from microorganisms are often complex to analyze and purify. A distribution analysis of calculated pK(a) values from the 34390 records in Antibase2008 revealed that within pH 2-11, 44% of all included compounds had an acidic functionality, 17% a basic functionality, and 9% both. This showed a great potential for using ion-exchange chromatography as an integral part of the separation procedure, orthogonal to the classic reversed-phase strategy. Thus, we investigated the use of an "explorative solid-phase extraction" (E-SPE) protocol using SAX, Oasis MAX, SCX, and LH-20 columns for targeted exploitation of chemical functionalities. E-SPE provides a minimum of fractions (15) for chemical and biological analyses and implicates development into a preparative scale methodology. Overall, this allows fast extract prioritization, easier dereplication, mapping of biological activities, and formulation of a purification strategy.

Månsson, Maria; Phipps, Richard Kerry

2010-01-01

265

Determination of apramycin in animal feeds by solid-phase extraction and liquid chromatography with precolumn derivatization and fluorescence detection.  

Science.gov (United States)

A high-performance liquid chromatographic method for determining apramycin in animal feeds was developed. Apramycin in feeds was extracted with 0.1 M HCl solution and cleaned up with an MCX solid-phase extraction column. The purified extract was derivatized with o-phthaldehyde, and components were separated on a C18 column and detected with a fluorescence detector. Mass spectrometric data confirmed that apramycin was derivatized at all the 4 primary amines on the apramycin molecule. Average recoveries at 8 included levels (5, 10, 20, 40, 80, 200, 400, and 2000 mg/kg) ranged from 92.2 to 100.5%, and the coefficients of variation were < 6.5%. Standard curves were linear over the range 0.05 to 10 microg/mL. The detection and quantitation limits were determined to be 0.2 and 1.0 mg/kg, respectively. PMID:17760324

Zhang, Liying; Wang, Zongyi; Chang, Biying; Yang, Wengjun

2007-01-01

266

Optimization of headspace solid-phase microextraction technique for extraction of volatile smokeless powder compounds in forensic applications.  

Science.gov (United States)

Smokeless powders are low explosives and are potentially found in cases involving firearms and improvised explosive devices. Apart from inorganic compound analysis, forensic determination of organic components of these materials appears as a promising alternative, especially the chromatographic techniques. This work describes the optimization of a solid-phase microextraction technique using an 85 ?m polyacrylate fiber followed by gas chromatography-flame ionization detection for smokeless powder. A multivariate experimental design was performed to optimize extraction-influencing parameters. A 2(4) factorial first-order design revealed that sample temperature and extraction time were the major influencing parameters. Doehlert matrix design has subsequently selected 66°C and 21 min as the compromised conditions for the two predetermined parameters. This extraction technique has successfully detected the headspace compounds of smokeless powders from different ammunition types and allowed for their differentiation. The novel technique allows more rapid sample preparation for chromatographic detection of smokeless powders. PMID:24611488

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

2014-07-01

267

Solid phase speciation of arsenic by sequential extraction in standard reference materials and industrially contaminated soil samples  

International Nuclear Information System (INIS)

Leaching experiments, a mineralogical survey and larger samples are preferred when arsenic is present as discrete mineral phases. - Availability, mobility, (phyto)toxicity and potential risk of contaminants is strongly affected by the manner of appearance of elements, the so-called speciation. Operational fractionation methods like sequential extractions have been applied for a long time to determine the solid phase speciation of heavy metals since direct determination of specific chemical compounds can not always be easily achieved. The three-step sequential extraction scheme recommended by the BCR and two extraction schemes based on the phosphorus-like protocol proposed by Manful (1992, Occurrence and Ecochemical Behaviours of Arsenic in a Goldsmelter Impacted Area in Ghana, PhD dissertation, at the RUG) were applied to four standard reference materials (SRM) and to a batch of samples from industrially contaminated sites, heavily contaminated with arsenic and heavy metals. The SRM 2710 (Montana soil) was found to be the most useful reference material for metal (Mn, Cu, Zn, As, Cd and Pb) fractionation using the BCR sequential extraction procedure. Two sequential extraction schemes were developed and compared for arsenic with the aim to establish a better fractionation and recovery rate than the BCR-scheme for this element in the SRM samples. The major part of arsenic was released from the heavily contaminated samples after NaOH-extraction. Inferior extraction variabaOH-extraction. Inferior extraction variability and recovery in the heavily contaminated samples compared to SRMs could be mainly contributed to subsample heterogeneity

268

Chromium speciation by solid phase extraction on Dowex M 4195 chelating resin and determination by atomic absorption spectrometry  

Energy Technology Data Exchange (ETDEWEB)

A solid phase extraction procedure has been established for chromium speciation in natural water samples prior to determination by atomic absorption spectrometry. The procedure is based on the solid phase extraction of the Cr(VI)- Dowex M 4195 chelating resin. After oxidation of Cr(III) to Cr(VI) by using H{sub 2}O{sub 2}, the presented method was applied to the determination of the total chromium. The level of Cr(III) is calculated by difference of total chromium and Cr(VI) levels. The procedure was optimized for some analytical parameters including pH, eluent type, flow rates of sample and eluent, matrix effects, etc. The presented method was applied for the speciation of chromium in natural water samples with satisfactory results (recoveries >95%, RSDs <10%). In the determinations of chromium species, flame atomic absorption spectrometer was used. The results were checked by using NIST SRM 2711 Montana soil and GBW 07603 Bush branched and leaves.

Saygi, Kadriye Ozlem; Tuzen, Mustafa [Gaziosmanpasa University, Faculty of Science and Arts, Chemistry Department, 60250 Tokat (Turkey); Soylak, Mustafa [Erciyes University, Faculty of Science and Arts, Chemistry Department, 38039 Kayseri (Turkey)], E-mail: msoylak@gmail.com; Elci, Latif [Pamukkale University, Faculty of Science and Arts, Chemistry Department, 20020 Denizli (Turkey)

2008-05-30

269

Simultaneous determination of 12 illicit drugs in whole blood and urine by solid phase extraction and UPLC-MS/MS.  

Science.gov (United States)

A rapid and sensitive method based on solid phase extraction and ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) for the simultaneous determination of amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylene-dioxymethamphetamine, N-methyl-1-(3,4-methyl-enedioxyphenyl)-2-butanamine, 3,4-methylenedioxyethylamphetamine, p-methoxymethamphetamine, ephedrine, N-methylephedrine, cathinone, methcathinone, and ketamine in whole blood and urine was developed and validated. Following solid phase extraction, the analytes were separated on ACQUITY UPLC BEH Phenyl column (100mm×2.1mm, 1.7?m) under gradient elution using a mobile phase containing of acetonitrile and 0.3% formic acid in water at a flow rate of 0.4mLmin(-1) and analyzed by a triplequadrupole mass spectrometer in the multiple reaction monitoring (MRM) mode. The proposed method was linear for each analyte with correlation coefficients over 0.99. Recovery validation studies showed accuracy bias below 4.4%. Acceptable precision was also obtained with a relative standard deviation below 8.9%. The sensitivity of the assay was found to be adequate for the quantitation of the illicit drugs in whole blood and urine sample and was higher than reported methods. The present method was proved to be reliable and robust for drug screening in forensic toxicological analysis. PMID:24631805

Zhang, Lin; Wang, Zhao-Hong; Li, Hong; Liu, Yong; Zhao, Meng; Jiang, Ye; Zhao, Wen-Song

2014-04-01

270

[Determination of ethyl glucuronide in human urine by solid phase extraction-gas chromatography-mass spectrometry].  

Science.gov (United States)

A solid phase extraction (SPE) and gas chromatography (GC) with mass spectrometry (MS) method for determination of ethyl glucuronide (EtG) in human urine was established. One mL urine sample was deproteinated by 100 microL 3 mol/L hydrochloric acid and cleaned up through a solid phase extraction column. The target analytes were eluted from an NH2-column with 4% ammonia solution and then treated with bis (trimethylsilyl) trifluoroacetamide (BSTFA) + trimethylchlorosilane (TMCS) (99:1) for derivatization. The derivatized samples were analyzed by GC-MS. Data were acquired in the selected ion monitoring (SIM) mode and the quantitation of EtG was done through internal standard method. Good linearity was obtained at the mass concentration range of 0.1 - 3.2 mg/L with a correlation coefficient (r) of 0.9921. The limit of detection (LOD) was 28.4 microg/L. The range of recoveries was 92.5% - 108.7%, and the relative standard deviations (RSDs) of intra-day and inter-day were all less than 5%. This method is sensitive, specific, accurate and can be applied to the determination of EtG for medicolegal identification and clinical laboratory. PMID:21598520

Yu, Tianxiao; Li, Qing; Wan, Tao; Li, Jianbo; Ding, Shijia

2011-02-01

271

Application of solid-phase extraction for the concentration of chromophores, fluorophores, and photosensitizers from lens protein digests.  

Science.gov (United States)

Solid-phase extraction was applied for the separation of protein digests obtained from aged human lenses, cataractous human lenses, calf lens proteins in vitro glycated with dehydroascorbic acid and native calf lens proteins. Four fractions were collected after stepwise elution with different solvents. The first fraction contained about 80% of the digested material possessing free amino groups. At the same time, the third and the fourth fractions were enriched in chromophores, fluorophores, and photosensitizing structures that originate mainly from advanced protein glycation. The comparison between the total digest and the fourth fraction based on their UV absorption at 330 nm, intensity of fluorescence (excitation/emission 350/450 nm), and production of singlet oxygen upon UVA irradiation argues that the solid-phase extraction was capable of concentrating the advanced glycation end-products about a hundredfold. Thus, this technique is a useful step for separation and concentration of fluorophores, chromophores, and photosensitizers from aged and glycated lens protein digests. PMID:25143146

Argirov, Ognyan K; Hubenova, Yolina; Argirova, Mariana D

2014-11-01

272

Solid phase extraction and a spectrophotometric method for the determination of trace amounts of gold with 4-rhodanineazo benzoic acid  

Directory of Open Access Journals (Sweden)

Full Text Available The synthesis and application of 4-rhodanineazo benzoic acid (4-BARA as a new chromogenic reagent for the determination of gold is des¬cribed. A highly sensitive, selective, and fast method for the determination of gold based on its rapid reaction with 4-rhodanineazo benzoic acid and the solid phase extraction of the colored complex on a reversed phase Clean-up® C5 cartridge was developed. In the presence of 0.02–0.2 mol/L phosphoric acid solution and a polyoxyethylene nonylphenol ether (emulsifier-OP medium, 4-rhodanineazo benzoic acid reacted with gold to form a colored complex with a gold-to-4-BARA molar ratio of 1:2. The complex was enriched by solid phase extraction with a reversed phase Clean-up® C5 cartridge. The complex was eluted from the cartridge with ethanol and an enrichment factor of 50 was achieved. In ethanol medium, the molar absorptivity of the complex was 2.39×105 L mol-1 cm-1 at 505 nm. The Beer Law was obeyed in the concentration range 0.01–?1.2 µg/mL. The relative standard deviation for eleven replicate samples at the 0.001 µg/mL level was 2.3 %. In the original sample, the detection limit was 8.0×10-5 µg/mL. This method was applied to the determination of trace amounts of gold in ore samples with good result.

ZHANG JIE HUANG

2009-09-01

273

Solid phase extraction and spectrophotometric determination of mercury in tobacco and tobacco additives with 5-(p-aminobenzylidene)-thiothiorhodanine  

Energy Technology Data Exchange (ETDEWEB)

A highly sensitive, selective and rapid method for the determination of mercury based on the rapid reaction of mercury(II) with 5-(p-aminobenzylidene)-thiorhodanine (ABTR) and the solid phase extraction of the colored chelate with C{sub 18} disks has been developed. At pH 3.5 and in the presence of emulsifier-OP medium, ABTR reacts with mercury(II) to form a red chelate of a 1:2 (mercury to ABTR) molar ratio. This chelate was enriched by solid phase extraction with C{sub 18} disks and the retained chelate eluted form the disks with dimethyl formamide (DMF). An enrichment factor of 50 was achieved. In the DMF medium, the molar absorptivity of the chelate is 1.21 X 10{sup 5} L mol{sup -1} cm{sup -1} at 545 nm, and Beer's law is obeyed in the 0.01{approx}3 {mu}g mL{sup -1} range in the measured solution. The relative standard deviation for eleven sample replicate measurements at the 0.01 {mu}g mL{sup -1} level is 1.7%. This method was applied to the determination of mercury in tobacco and tobacco additives and good preconcentration was found between proposed and comparative methods results. (author)

Yang, Weizhu; Yang, Guangyu [Yunnan University, Kunming (China). Dept. of Chemistry]. E-mail: ygy1110@163.com; Hu, Qun; Ma, Jing; Wang, Liming [Kunming Science and Technology University, Kunming (China). School of Materials and Metallurgy; Xie, Gang [Yunnan Academy of Tobacco Science, Kunming (China)

2006-09-15

274

Silver nanoparticles as a new solid-phase adsorbent and its application to preconcentration and determination of lead from biological samples.  

Science.gov (United States)

A new, simple, and fast method for preconcentration and determination of trace amount of lead from biological samples was developed by modified silver nanoparticle-based solid-phase extraction technique and graphite furnace atomic absorption spectrometry. In this study, morin was used as a complexing agent. Some factors influencing the recovery of lead including pH, sample flow rate, type, flow rate, and least amount of the eluent for elution of the lead from silver nanoparticles were studied and optimized. Under the optimum conditions, the detection limit of this method was 68 ng L(-1), and the relative standard deviation was 4.1% (n?=?10, c?=?20 ?g L(-1)). The developed procedure was validated by the analysis of certified reference material and applied to the recovery and determination of lead in biological samples. PMID:21384144

Khajeh, Mostafa; Sanchooli, Esmael

2011-12-01

275

Solid-phase/supercritical-fluid extraction for liquid chromatography of phenolic compounds in freshwater microalgae and selected cyanobacterial species.  

Science.gov (United States)

In the present paper a new extraction technique based on the combination of solid-phase/supercritical-fluid extraction (SPE/SFE) with subsequent reversed-phase HPLC is described. The SPE/SFE extractor was originally constructed from SPE-cartridge incorporated into the SFE extraction cell. Selected groups of benzoic acid derivatives (p-hydroxybenzoic, protocatechuic, gallic, vanillic and syringic acid), hydroxybenzaldehydes (4-hydroxybenzaldehyde and 3,4-dihydroxybenzaldehyde) and cinnamic acid derivatives (o-coumaric, p-coumaric, caffeic, ferulic, sinapic and chlorogenic acid) were extracted. Cyclic addition of binary extraction solvent system based on methanol:water (1:1, v/v) and methanol/ammonia aqueous solution was used for extraction at 40MPa and 80 degrees C. The p-hydroxybenzoic, protocatechuic, vanillic, syringic, caffeic and chlorogenic acid; 4-hydroxybenzaldehyde and 3,4-dihydroxybenzaldehyde were identified by HPLC-electrospray mass spectrometry in SPE/SFE extracts of acid hydrolyzates of microalga (Spongiochloris spongiosa) and cyanobacterial strains (Spirulina platensis, Anabaena doliolum, Nostoc sp., and Cylindrospermum sp.). For the identification and quantification of the compounds the quasi-molecular ions [M-H](-) and specific fragments were analysed by quadrupole mass spectrometry analyzer. Our analysis showed that the microalgae and cyanobacteria usually contained phenolic acids or aldehydes at microg levels per gram of lyophilized sample. The proposed SPE/SFE extraction method would be useful for the analysis of different plant species containing trace amount of polar fraction of phenols. PMID:19111311

Klejdus, B; Kopecký, J; Benesová, L; Vacek, J

2009-01-30

276

Multiresidue determination of UV filters in water samples by solid-phase extraction and liquid chromatography with tandem mass spectrometry analysis.  

Science.gov (United States)

UV filters, contained in sunscreens and other cosmetic products, as well as in some plastics and industrial products, are nowadays considered contaminants of emerging concern because their widespread and increasing use has lead to their presence in the environment. Furthermore, some UV filters are suspected to have endocrine disruption activity. In the present work, we developed an analytical method based on liquid chromatography with tandem mass spectrometry for the determination of UV filters in tap and lake waters. Sixteen UV filters were extracted from water samples by solid-phase extraction employing graphitized carbon black as adsorbent material. Handling 200 mL of water sample, satisfactory recoveries were obtained for almost all the analytes. The limits of detection and quantification of the method were comparable to those reported in other works, and ranged between 0.7-3.5 and 1.9-11.8 ng/L, respectively; however in our case the number of investigated compounds was larger. The major encountered problem in method development was to identify the background contamination sources and reduce their contribution. UV filters were not detected in tap water samples, whereas the analyses conducted on samples collected from three different lakes showed that the swimming areas are most subject to UV filter contamination. PMID:25124312

Capriotti, Anna Laura; Cavaliere, Chiara; Piovesana, Susy; Samperi, Roberto; Stampachiacchiere, Serena; Ventura, Salvatore; Laganà, Aldo

2014-10-01

277

Application of magnetic solid phase extraction for separation and determination of aflatoxins B ? and B? in cereal products by high performance liquid chromatography-fluorescence detection.  

Science.gov (United States)

A simple and sensitive method based on the magnetic solid phase extraction with modified magnetic nanoparticles followed by high performance liquid chromatography with fluorescence detection has been developed for extraction and determination of aflatoxins B1 (AFB1) and B2 (AFB2) in cereal products. Magnetic nanoparticle coated with 3-(trimethoxysilyl)-1-propanthiol (TMSPT) and modified with 2-amino-5-mercapto-1,3,4-thiadiazole (AMT) was used as an antibody-free adsorbent. Under the optimal conditions, the calibration curves for AFB1 and AFB2 were linear in the ranges of 0.2-15 ?g L(-1) and 0.04-3 ?g L(-1), respectively. Detection limit was 0.041 ?g L(-1) for AFB1 and 0.013 ?g L(-1) for AFB2. The proposed method was successfully applied to the determination of AFB1 and AFB2 in spiked corn and rice samples with an average recovery of 93.5%. The results demonstrated that the developed method is simple, rapid, inexpensive, accurate and remarkably free from interference effects. PMID:24814005

Hashemi, Mahdi; Taherimaslak, Zohreh; Rashidi, Somayeh

2014-06-01

278

Flame atomic absorption spectrometric determination of ?g amounts of Fe (III) ions after solid phase extraction using modified octadecyl silica membrane disks  

International Nuclear Information System (INIS)

A simple, rapid and reliable method has been developed to selectively separate and concentrate ultra trace amounts of Fe (III) ions from aqueous samples for the measurement by flame atomic absorption spectrometry (FAAS). By the passage of aqueous samples through an octadecyl silica membrane disk modified by a recently synthesized Schiff base (Bis-(4-nitro phenyl azo) salisilidine-1,3-diamino propane), Fe(III) ions adsorb quantitatively and most of matrix elements will pass through the disk to drain. The retained iron ions are then stripped from the disk by minimal amount of 0.1 mol l-1 sulfuric acid as eluent. Extraction efficiency and the influence of pH, flow rates, amount of ligand, type and least amount of stripping acid as eluent were evaluated. The recovery of the iron from aqueous solution on the membrane disk modified with 3 mg Schiff's base was quantitative over pH 2-4.5. The linear dynamic range of the proposed method for Fe (III) ions was found in a wide concentration range of 0.20 (± 0.05)-680 (± 2) ?g l-1. The detection limit and preconcentration factor of this solid phase extraction method were found 20.0 (± 0.7) ng l-1 and 100 respectively. The reproducibility of the procedure is at the most 1.5%

279

Solid-phase extraction of trace metal ions with magnetic nanoparticles modified with 2,6-diaminopyridine  

International Nuclear Information System (INIS)

We have modified silica-coated Fe3O4 nanoparticles with 2,6-diaminopyridine and used these for selective magnetic solid-phase extraction of trace amounts of metal ions. The nanoparticles were characterized by transmission electron microscopy and Fourier transform infrared spectroscopy. Quantitative extraction of trace amounts of Cu(II) and Zn(II) from mixed-ion solutions was accomplished at an optimal pH value of 6 within less than 10 min. The metal ions were eluted from the sorbent with hydrochloric acid. Common electrolytes and chemically related metal ions do not interfere. The relative standard deviations of the method are <4 %. It was successfully applied to the separation and preconcentration of trace metal ions from the certified reference materials GBW 08301 (river sediment) and GBW 08607 (water solution), in natural water, and in samples of vegetable with satisfying results. (author)

280

Magnetic nanoparticles modified with polydimethylsiloxane and multi-walled carbon nanotubes for solid-phase extraction of fluoroquinolones  

International Nuclear Information System (INIS)

We have surface-functionalized magnetic particles (MPs) with polydimethylsiloxane and multi-walled carbon nanotubes in a two-step reaction. The MPs were applied to solid-phase extraction of the fluoroquinolones ofloxacin, norfloxacin, ciprofloxacin, enrofloxacin prior to their determination by capillary liquid chromatography. The effects of sample pH, adsorption time, type of eluent, desorption time and desorption temperature were investigated. Under the optimum conditions, the extraction efficiencies are in the range from 81.5 % to 94.1 %, with relative standard deviations (RSDs) of -1. The method was applied to the analysis of spiked mineral water and honey. The recoveries for the fluoroquinolones in the real samples range from 84.0 % to 112 %, with RSDs ranging from 2.9 % to 7.8 %. (author)

 
 
 
 
281

Chemically modified polymeric resins for solid-phase extraction and group separation prior to analysis by liquid or gas chromatography  

Energy Technology Data Exchange (ETDEWEB)

Polystyrene divinylbenzene was modified by acetyl, sulfonic acid, and quaternary ammonium groups. A resin functionalized with an acetyl group was impregnated in a PTFE membrane and used to extract and concentrate phenolic compounds from aqueous samples. The acetyl group created a surface easily wetted, making it an efficient adsorbent for polar compounds in water. The membrane stabilized the resin bed. Partially sulfonated high surface area resins are used to extract and group separate an aqueous mixture of neutral and basic organics; the bases are adsorbed electrostatically to the sulfonic acid groups, while the neutraons are adsorbed hydrophobically. A two-step elution is then used to separate the two fractions. A partially functionalized anion exchange resin is used to separate organic acids and phenols from neutrals in a similar way. Carboxylic acids are analyzed by HPLC and phenols by GC.

Schmidt, L.W.

1993-07-01

282

Solid phase speciation of arsenic by sequential extraction in standard reference materials and industrially contaminated soil samples  

Energy Technology Data Exchange (ETDEWEB)

Leaching experiments, a mineralogical survey and larger samples are preferred when arsenic is present as discrete mineral phases. - Availability, mobility, (phyto)toxicity and potential risk of contaminants is strongly affected by the manner of appearance of elements, the so-called speciation. Operational fractionation methods like sequential extractions have been applied for a long time to determine the solid phase speciation of heavy metals since direct determination of specific chemical compounds can not always be easily achieved. The three-step sequential extraction scheme recommended by the BCR and two extraction schemes based on the phosphorus-like protocol proposed by Manful (1992, Occurrence and Ecochemical Behaviours of Arsenic in a Goldsmelter Impacted Area in Ghana, PhD dissertation, at the RUG) were applied to four standard reference materials (SRM) and to a batch of samples from industrially contaminated sites, heavily contaminated with arsenic and heavy metals. The SRM 2710 (Montana soil) was found to be the most useful reference material for metal (Mn, Cu, Zn, As, Cd and Pb) fractionation using the BCR sequential extraction procedure. Two sequential extraction schemes were developed and compared for arsenic with the aim to establish a better fractionation and recovery rate than the BCR-scheme for this element in the SRM samples. The major part of arsenic was released from the heavily contaminated samples after NaOH-extraction. Inferior extraction variability and recovery in the heavily contaminated samples compared to SRMs could be mainly contributed to subsample heterogeneity.

Herreweghe, Samuel van; Swennen, Rudy; Vandecasteele, Carlo; Cappuyns, Valerie

2003-04-01

283

Optimization of the Matrix Solid Phase Dispersion Extraction Procedure for the Analysis of Polybrominated Diphenyl Ethers in Human Placenta  

Science.gov (United States)

Characterization of prenatal exposure to hazardous chemicals most often relies upon the analysis of cord blood. However, human placenta is an appropriate tissue alternative with noteworthy advantages. Owing to analytical challenges, reports on placental levels of toxic chemicals are limited. The purpose of this study was to establish a reliable, cost effective, and relatively fast and simple method to extract polybrominated diphenyl ethers (PBDEs) from human placenta for analysis using gas chromatography coupled with mass spectrometry (GC/MS). The matrix solid phase dispersion (MSPD) method was optimized for the extraction and analysis of 43 PBDEs (including BDE209) from human placenta samples. Different sorbents, sample conditions, grinding methods, elution solvents, and single and repeated extractions were compared for their effects on the extraction efficiency. The performance of the optimized method was validated by analyzing spiked placenta samples and a standard reference material of fish tissue. Congener specific PBDE recovery ranged from 91to 114% for the spiked samples and 89 to 115% for a standard reference material (SRM) of fish tissue. The optimized MSPD procedure was compared with two conventional extraction methods. The extraction efficiency of MSPD was found to be comparable with that of the traditional Soxhlet method and superior to that using a liquid extraction method. Twenty two PBDEs were detected in all of the 5 samples collected in Chicago in 2008. This is the first description of PBDEs detected in human placentas reported in the U.S. PMID:19863067

Dassanayake, R. M. A. Priyanthi S.; Wei, Hua; Chen, Rachel C.; Li, An

2009-01-01

284

Solid phase speciation of arsenic by sequential extraction in standard reference materials and industrially contaminated soil samples.  

Science.gov (United States)

Availability, mobility, (phyto)toxicity and potential risk of contaminants is strongly affected by the manner of appearance of elements, the so-called speciation. Operational fractionation methods like sequential extractions have been applied for a long time to determine the solid phase speciation of heavy metals since direct determination of specific chemical compounds can not always be easily achieved. The three-step sequential extraction scheme recommended by the BCR and two extraction schemes based on the phosphorus-like protocol proposed by Manful (1992, Occurrence and Ecochemical Behaviours of Arsenic in a Goldsmelter Impacted Area in Ghana, PhD dissertation, at the RUG) were applied to four standard reference materials (SRM) and to a batch of samples from industrially contaminated sites, heavily contaminated with arsenic and heavy metals. The SRM 2710 (Montana soil) was found to be the most useful reference material for metal (Mn, Cu, Zn, As, Cd and Pb) fractionation using the BCR sequential extraction procedure. Two sequential extraction schemes were developed and compared for arsenic with the aim to establish a better fractionation and recovery rate than the BCR-scheme for this element in the SRM samples. The major part of arsenic was released from the heavily contaminated samples after NaOH-extraction. Inferior extraction variability and recovery in the heavily contaminated samples compared to SRMs could be mainly contributed to subsample heterogeneity. PMID:12547522

Van Herreweghe, Samuel; Swennen, Rudy; Vandecasteele, Carlo; Cappuyns, Valérie

2003-01-01

285

Solid phase nucleic acid extraction technique in a microfluidic chip using a novel non-chaotropic agent: dimethyl adipimidate.  

Science.gov (United States)

Here, we present a silicon microfluidic system for the purification and extraction of nucleic acids from human body fluid samples utilizing a dimethyl adipimidate (DMA)-based solid-phase extraction method. We propose DMA, which has been used as an amino-reactive cross-linking agent within cells and proteins, as a non-chaotropic reagent for the capture of nucleic acids to overcome the limitations of existing chaotropic and non-chaotropic techniques such as low binding efficiency, PCR inhibition and so on. DMA contains bi-functional imidoesters that form reversible cross-linking structures with DNA therefore providing a high surface-area to volume ratio for capturing DNA without structurally modifying microfluidic channels. In this work, we have first demonstrated highly efficient capture and purification of genomic DNA (T24 cell line) with DMA using a label-free silicon microring resonator sensor device. In addition, we observed the improvement of the DNA amplification efficiency by using the proposed technique for both the genetic (HRAS) and epigenetic (RAR?) analysis of DNA biomarkers. Particularly, we confirmed that the DMA-based solid-phase extraction technique can be applied for the extraction of genomic DNA with higher purity (p < 0.001) using human body fluids (blood and urine) in silicon microfluidic devices compared to other chaotropic methods. Therefore, the proposed technique would be able to harmonize with a micro-total analysis system platform for the analysis of genetic and epigenetic DNA biomarkers related to human diseases in the field of point-of-care (POC) diagnostic applications. PMID:24263404

Shin, Yong; Perera, Agampodi Promoda; Wong, Chee Chung; Park, Mi Kyoung

2014-01-21

286

Determination of ibuprofen in combined dosage forms and cream by direct UV spectrophotometry after solid-phase extraction.  

Science.gov (United States)

Solid-phase extraction method followed by direct UV spectrophotometry at 264 nm was developed and applied for the selective ibuprofen determination in two-component formulation of ibuprofen and pseudoephedrine-HCl, combined powder which contains ibuprofen in the form of salt with L-arginine and 10% ibuprofen cream. Procedures for ibuprofen determination in complex pharmaceutical preparations by direct UV spectrophotometry lack selectivity because of interferences of other active substances and fat components. A limited number of spectrophotometric methods applicable to these samples are based on derivative (first and second-order) UV spectroscopy. Common HPLC procedures are more selective but more expensive and for creams also require some type of extraction because the large amount of oily excipients would clog up the column. The proposed solid-phase extraction method proved to be suitable for analysis of ibuprofen in combined tablets, powders and creams by direct UV spectrophotometry. Also the method provides an effective clean-up of the cream and allows ibuprofen determination by HPLC analysis. For the extraction three different commercial sorbents were tested: anion exchange Oasis MAX, hydrophilic-lipophilic balanced Oasis HLB and reverse-phase Chromabond C18ec. The optimization of the SPE method was first done on standard ibuprofen solutions and then the suitability of the method was checked on solutions of commercial pharmaceutical samples. The method yields good results for all three types of commercial preparations on the anion-exchange Oasis MAX cartridges, with recoveries of 90-100.2%. The interferences in UV analysis were not registered and good precision (RSD method has been verified as accurate as the reference HPLC with the great advantage of less expensive instrumentation. For this reason, the method would be suitable for a routine and rapid drug quality control. PMID:23757930

Sunaric, Slavica; Petkovic, Milica; Denic, Marko; Mitic, Snezana; Pavlovic, Aleksandra

2013-01-01

287

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of pesticides in water by C-18 solid-phase extraction and capillary-column gas chromatography/mass spectrometry with selected-ion monitoring  

Science.gov (United States)

A method for the isolation of 41 pesticides and pesticide metabolites in natural-water samples using C-18 solid-phase extraction and determination by capillary-column gas chromatography/mass spectrometry with selected-ion monitoring is described. Water samples are filtered to remove suspended particulate matter and then are pumped through disposable solid-phase extraction columns containing octadecyl-bonded porous silica to extract the pesticides. The columns are dried using carbon dioxide or nitrogen gas, and adsorbed pesticides are removed from the columns by elution with 3.0 milliliters of hexane-isopropanol (3:1). Extracted pesticides are determined by capillary- column gas chromatography/mass spectrometry with selected-ion monitoring of three characteristic ions. The upper concentration limit is 4 micrograms per liter (g/L) for most pesticides, with the exception of widely used corn herbicides--atrazine, alachlor, cyanazine, and metolachlor--which have upper concentration limits of 20 g/L. Single- operator method detection limits in reagent-water samples range from 0.001 to 0.018 g/L. Average short-term single-operator precision in reagent- water samples is 7 percent at the 0.1- and 1.0-g/L levels and 8 percent at the 0.01-g/L level. Mean recoveries in reagent-water samples are 73 percent at the 0.1- and 1.0-g/L levels and 83 percent at the 0.01-g/L level. The estimated holding time for pesticides after extraction on the solid-phase extraction columns was 7 days. An optional on-site extraction procedure allows for samples to be collected and processed at remote sites where it is difficult to ship samples to the laboratory within the recommended pre-extraction holding time.

Zaugg, Steven D.; Sandstrom, Mark W.; Smith, Steven G.; Fehlberg, Kevin M.

1995-01-01

288

Surfactant-enhanced liquid-liquid microextraction coupled to micro-solid phase extraction onto highly hydrophobic magnetic nanoparticles  

International Nuclear Information System (INIS)

We are presenting a simplified alternative method for dispersive liquid-liquid microextraction (DLLME) by resorting to the use of surfactants as emulsifiers and micro solid-phase extraction (?-SPE). In this combined procedure, DLLME of hydrophobic components is initially accomplished in a mixed micellar/microemulsion extractant phase that is prepared by rapidly mixing a non-ionic surfactant and 1-octanol in aqueous medium. Then, and in contrast to classic DLLME, the extractant phase is collected by highly hydrophobic polysiloxane-coated core-shell Fe2O3(at)C magnetic nanoparticles. Hence, the sample components are the target analyte in the DLLME which, in turn, becomes the target analyte of the ?-SPE step. This 2-step approach represents a new and simple DLLME procedure that lacks tedious steps such as centrifugation, thawing, or delicate collection of the extractant phase. As a result, the analytical process is accelerated and the volume of the collected phase does not depend on the volume of the extraction solvent. The method was applied to extract cadmium in the form of its pyrrolidine dithiocarbamate chelate from spiked water samples prior to its determination by FAAS. Detection limits were brought down to the low ?g L?1 levels by preconcentrating 10 mL samples with satisfactory recoveries (96.0–108.0 %). (author)

289

Comparative evaluation of liquid-liquid extraction, solid-phase extraction and solid-phase microextraction for the gas chromatography-mass spectrometry determination of multiclass priority organic contaminants in wastewater.  

Science.gov (United States)

The European Water Framework Directive (WFD) 2000/60/EC establishes guidelines to control the pollution of surface water by sorting out a list of priority substances that involves a significant risk to or via the aquatic systems. In this article, the analytical performance of three different sample preparation methodologies for the GC-MS/MS determination of multiclass organic contaminants-including priority comprounds from the WFD-in wastewater samples using gas chromatography-mass spectrometry was evaluated. The methodologies tested were: (a) liquid-liquid extraction (LLE) with n-hexane; (b) solid-phase extraction (SPE) with C18 cartridges and elution with ethyl acetate:dichloromethane (1:1 (v/v)), and (c) headspace solid-phase microextraction (HS-SPME) using two different fibers: polyacrylate and polydimethylsiloxane/carboxen/divinilbenzene. Identification and confirmation of the selected 57 compounds included in the study (comprising polycyclic aromatic hydrocarbons (PAHs), pesticides and other contaminants) were accomplished using gas chromatography tandem mass spectrometry (GC-MS/MS) with a triple quadrupole instrument operated in the multiple reaction monitoring (MRM) mode. Three MS/MS transitions were selected for unambiguous confirmation of the target chemicals. The different advantages and pitfalls of each method were discussed. In the case of both LLE and SPE procedures, the method was validated at two different concentration levels (15 and 150 ng L(-1)) obtaining recovery rates in the range 70-120% for most of the target compounds. In terms of analyte coverage, results with HS-SPME were not satisfactory, since 14 of the compounds tested were not properly recovered and the overall performance was worse than the other two methods tested. LLE, SPE and HS-SPME (using polyacrylate fiber) procedures also showed good linearity and precision. Using any of the three methodologies tested, limits of quantitation obtained for most of the detected compounds were in the low nanogram per liter range. PMID:24209357

Robles-Molina, José; Gilbert-López, Bienvenida; García-Reyes, Juan F; Molina-Díaz, Antonio

2013-12-15

290

Rapid, low level determination of silver(I) in drinking water by colorimetric-solid-phase extraction  

International Nuclear Information System (INIS)

A rapid, highly sensitive two-step procedure for the trace analysis of silver(I) is described. The method is based on: (1) the solid-phase extraction (SPE) of silver(I) from a water sample onto a disk impregnated with a silver-selective colorimetric reagent, and (2) the determination of the amount of complexed analyte extracted by the disk by diffuse reflectance spectroscopy (DRS). This method, called colorimetric-solid-phase extraction (C-SPE), was recently shown effective in determining low concentrations (0.1-5.0 mg/ml) of iodine and iodide in drinking water. This report extends C-SPE to the trace (?4 ?g/l) level monitoring of silver(I) which is a biocide used on the International Space Station (ISS). The determination relies on the manually driven passage of a water sample through a polystyrene-divinylbenzene disk that has been impregnated with the colorimetric reagent 5-(p-dimethylaminobenzylidene) rhodanine (DMABR) and with an additive such as a semi-volatile alcohol (1,2-decanediol) or nonionic surfactant (Brij 30). The amount of concentrated silver(I) is then determined in a few seconds by using a hand-held diffuse reflectance spectrometer, with a total sample workup and readout time of ?60 s. Importantly, the additive induces the uptake of water by the disk, which creates a local environment conducive to silver(I) complexation at an extremely high concentration factor (?800). There is no detectable reaction between silver(I) and impregnated DMABR in thlver(I) and impregnated DMABR in the absence of the additive. This strategy represents an intriguing new dimension for C-SPE in which additives, directly loaded in the disk material, provide a means to manipulate the reactivity of the impregnated reagent

291

Rapid, low level determination of silver(I) in drinking water by colorimetric-solid-phase extraction  

Energy Technology Data Exchange (ETDEWEB)

A rapid, highly sensitive two-step procedure for the trace analysis of silver(I) is described. The method is based on: (1) the solid-phase extraction (SPE) of silver(I) from a water sample onto a disk impregnated with a silver-selective colorimetric reagent, and (2) the determination of the amount of complexed analyte extracted by the disk by diffuse reflectance spectroscopy (DRS). This method, called colorimetric-solid-phase extraction (C-SPE), was recently shown effective in determining low concentrations (0.1-5.0 mg/ml) of iodine and iodide in drinking water. This report extends C-SPE to the trace ({approx}4 {mu}g/l) level monitoring of silver(I) which is a biocide used on the International Space Station (ISS). The determination relies on the manually driven passage of a water sample through a polystyrene-divinylbenzene disk that has been impregnated with the colorimetric reagent 5-(p-dimethylaminobenzylidene) rhodanine (DMABR) and with an additive such as a semi-volatile alcohol (1,2-decanediol) or nonionic surfactant (Brij 30). The amount of concentrated silver(I) is then determined in a few seconds by using a hand-held diffuse reflectance spectrometer, with a total sample workup and readout time of {approx}60 s. Importantly, the additive induces the uptake of water by the disk, which creates a local environment conducive to silver(I) complexation at an extremely high concentration factor ({approx}800). There is no detectable reaction between silver(I) and impregnated DMABR in the absence of the additive. This strategy represents an intriguing new dimension for C-SPE in which additives, directly loaded in the disk material, provide a means to manipulate the reactivity of the impregnated reagent.

Arena, Matteo P.; Porter, Marc D.; Fritz, James S

2003-04-15

292

Solid-phase extraction and purification of membrane proteins using a UV-modified PMMA microfluidic bioaffinity ?SPE device.  

Science.gov (United States)

We present a novel microfluidic solid-phase extraction (?SPE) device for the affinity enrichment of biotinylated membrane proteins from whole cell lysates. The device offers features that address challenges currently associated with the extraction and purification of membrane proteins from whole cell lysates, including the ability to release the enriched membrane protein fraction from the extraction surface so that they are available for downstream processing. The extraction bed was fabricated in PMMA using hot embossing and was comprised of 3600 micropillars. Activation of the PMMA micropillars by UV/O3 treatment permitted generation of surface-confined carboxylic acid groups and the covalent attachment of NeutrAvidin onto the ?SPE device surfaces, which was used to affinity select biotinylated MCF-7 membrane proteins directly from whole cell lysates. The inclusion of a disulfide linker within the biotin moiety permitted release of the isolated membrane proteins via DTT incubation. Very low levels (?20 fmol) of membrane proteins could be isolated and recovered with ?89% efficiency with a bed capacity of 1.7 pmol. Western blotting indicated no traces of cytosolic proteins in the membrane protein fraction as compared to significant contamination using a commercial detergent-based method. We highlight future avenues for enhanced extraction efficiency and increased dynamic range of the ?SPE device using computational simulations of different micropillar geometries to guide future device designs. PMID:24487280

Battle, Katrina N; Jackson, Joshua M; Witek, Ma?gorzata A; Hupert, Mateusz L; Hunsucker, Sally A; Armistead, Paul M; Soper, Steven A

2014-03-21

293

Rapid mixed mode solid phase extraction method for the determination of acrylamide in roasted coffee by HPLC-MS/MS.  

Science.gov (United States)

In this work, a rapid and reliable purification method based on a single mixed solid phase extraction (SPE) column, for the determination of acrylamide in roasted coffee by liquid chromatography-tandem mass spectrometry, was developed. Deuterium labelled d(3)-acrylamide was used as internal standard. Acrylamide was extracted by 10 mL of water and the extract purified by a single SPE column consisting of 0.5 g of an in-house prepared mixture of C18, strong cation (SCX) and anion exchange (SAX) sorbents in the ratio 2/1.5/1.5 (w/w/w). The amount of the three sorbents was optimised in order to eliminate the main interfering compounds present in coffee extracts, such as melanoidins, trigonelline, chlorogenic acids and caffeine. The SPE procedure was very simple and consisted of pushing 1 mL of an aqueous coffee extract through the SPE column followed by 1 mL of water which was collected for the analysis. The method was tested on six samples of roasted coffee of different composition and roasting level. The repeatability of the method, expressed as relative standard deviation (n=6), was lower than 5%. The recovery of acrylamide at three spiked levels ranged from 92% to 95%. The limits of detection (LOD) and quantitation (LOQ) were 5 and 16 ?g kg(-1), respectively. PMID:22980859

Bortolomeazzi, Renzo; Munari, Marina; Anese, Monica; Verardo, Giancarlo

2012-12-15

294

Solid phase extraction as a cleanup step before microextraction of diclofenac and mefenamic acid using nanostructured solvent.  

Science.gov (United States)

A new pretreatment method, solid-phase extraction combined with supramolecular solvents, was proposed for the first time for extraction of diclofenac (DIC) and mefenamic acid (MEF) from urine and water samples. Supramolecular solvent (SUPRAS) is a nano-structured liquid, generated from the amphiphiles through a sequential self-assembly process occurring on two scales, molecular and nano. SUPRAS tested were generated from solutions of reverse micelles of decanoic acid (DeA) in tetrahydrofuran (THF) by addition of water, which acted as the coacervating agent. In the present study, due to matrix effect, drugs were first extracted from the samples by SPE. The extracted analytes were then eluted from the sorbent with THF, and the eluate was subjected to SUPRAS formation (SUPRASF) process. Finally, the analytes in the SUPRAS were separated and determined by HPLC-UV. Several parameters affecting the SPE-SUPRASF process were investigated and optimized. The new method provides enrichment factors in the range of 431-489 for MEF and DIC, respectively. Calibration plots are linear in the range of 2-200 ?g L(-1) for MEF and 1-200 ?g L(-1) for DIC, with correlation of determination (r(2)) ranging from 0.996 to 0.999. The method was successfully applied for extraction and determination of analytes in urine and water samples and relative recoveries of the studied compounds were obtained in the range of 90.4-103.8%. PMID:23598005

Rezaei, Fatemeh; Yamini, Yadollah; Moradi, Morteza; Ebrahimpour, Behnam

2013-02-15

295

Analysis of the herbicide bispyribac-sodium in rice by solid phase extraction and high performance liquid chromatography.  

Science.gov (United States)

Bispyribac-sodium is a commonly used herbicide. An analytical method employing HPLC with a diode array detector was developed to determine bispyribac-sodium residues in rice. The liquid-liquid partition and anion exchange solid phase procedures that were developed provide effective extraction and cleanup methods for analysis feasibility. Recoveries ranged from 83.98 to 98.51% with a relative standard deviation of 0.56-6.36% and sensitivity of 0.01 mg/kg. Bispyribac-sodium residues in rice were further confirmed by LC-MS. The proposed method was successfully applied to the analysis of bispyribac-sodium residues from a rice field in Jiangxi Province that had been treated using bispyribac-sodium. PMID:21298252

Wu, Shimin; Mei, Jun

2011-03-01

296

Methylene crosslinked calix[6]arene hexacaarboxylic acid resin: a highly efficient solid phase extractant for decontamination of lead bearing effluents.  

Science.gov (United States)

Calixarene-based cation exchange resin has been developed by methylene crosslinking of calix[6]arene hexacarboxylic acid derivative and the resin has been exploited for solid phase extraction of some toxic heavy metal ions. The selectivity order of the resin towards some metal ions follows the order Pb(II) > Cu(II)> Zn(II), Ni(II), Co(II). The maximum lead ion binding capacity of the resin was found to be 1.30 mmol g(-1) resin. The loaded lead was quantitatively eluted with dilute acid solution regenerating the resin. Mutual separation of Pb(II), Cu(II) and Zn(II) was achieved by using the column packed with the resin. PMID:21835544

Adhikari, Birendra Babu; Gurung, Manju; Kawakita, Hidetaka; Jumina; Ohto, Keisuke

2011-10-15

297

Determination of fipronil in bovine plasma by solid-phase extraction and liquid chromatography with ultraviolet detection  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english A fast and efficient method has been developed and validated for the determination of fipronil in bovine plasma. Samples were subjected to solid-phase extraction (SPE) followed by reversed phase liquid chromatography (LC) separation, using acetonitrile/water (60:40 v/v) as the mobile phase with a fl [...] ow rate of 1.0 mL/min and ultraviolet (UV) detection at 210 nm. Ethiprole was used as the internal standard (IS). The method was found to be linear over the range 5-500 ng/mL (r = 0.999). The limit of quantitation (LOQ) was validated at 5 ng/mL. The method was successfully applied to monitor plasma concentrations following subcutaneous administration of fipronil in cattle.

Yara P., Cid; Thais P., Ferreira; Deborah M. V. C., Medeiros; Rodrigo M., Oliveira; Nathália C. C., Silva; Viviane S., Magalhães; Fábio B., Scott.

298

Multi-element pre-concentration of heavy metal ions by solid phase extraction on Chromosorb 108  

International Nuclear Information System (INIS)

A multi-element preconcentration procedure for solid phase extraction on Chromosorb 108 as bathocuproinedisulfonic acid chelates and flame atomic absorption spectrometric determinations of some heavy metal ions in environmental samples is proposed in the present work. The influences of analytical parameters including pH of the aqueous solution, amounts of reagents, flow rates of sample and eluent solutions, sample volume etc. on the quantitative recoveries of copper, cadmium, lead, zinc, manganese, iron, chromium, nickel and cobalt ions were investigated. The effects of concomitant ions on the retentions of the analytes were also examined. The presented preconcentration procedure was applied to the determination of metal ions in reference standard materials (NRCC-SLRS 4 Riverine Water, SRM 1515 Apple leaves and GBW 07605 Tea) and some real samples including tap and river water, red wine, rice, black tea and honey

299

Trace determination of pharmaceuticals and other wastewater-derived micropollutants by solid phase extraction and gas chromatography/mass spectrometry.  

Science.gov (United States)

The presence of pharmaceuticals and other wastewater-derived micropollutants in surface and groundwaters is receiving intense public and scientific attention. Yet simple GC/MS methods that would enable measurement of a wide range of such compounds are scarce. This paper describes a GC/MS method for the simultaneous determination of 13 pharmaceuticals (acetaminophen, albuterol, allopurinol, amitriptyline, brompheniramine, carbamazepine, carisoprodol, ciclopirox, diazepam, fenofibrate, metoprolol, primidone, and terbinafine) and 5 wastewater-derived contaminants (caffeine, diethyltoluamide, n-butylbenzene sulfonamide, n-nonylphenol, and n-octylphenol) by solid phase extraction (SPE) and derivatization with BSTFA. The method was applied to the analysis of raw and treated sewage samples obtained from a wastewater treatment plant located in the mid-Atlantic United States. All analytes were detected in untreated sewage, and 14 of the 18 analytes were detected in treated sewage. PMID:20015510

Bisceglia, Kevin J; Yu, Jim T; Coelhan, Mehmet; Bouwer, Edward J; Roberts, A Lynn

2010-01-22

300

Determination of selenoprotein P in human plasma by solid phase extraction and inductively coupled plasma mass spectrometry  

DEFF Research Database (Denmark)

A method based on solid phase extraction was developed for the determination of selenoprotein P as selenium in human plasma. Separation of selenoprotein P from other selenium-containing proteins was accomplished by immobilized metal-ion affinity chromatography. The selenium content was subsequently measured by inductively coupled plasma mass spectrometry (ICP-MS) monitoring the Se-82 isotope. Linear response was observed in the concentration range 0.3-70.8 mu g/l selenium as selenoprotein P with a correlation coefficient of 0.9994. The precision expressed as relative standard deviation was better than 2% in this range. The estimated limit of detection was 2 mu g/l and the experimentally verified quantification limit was 5 mu g/l, giving a relative standard deviation less than 2%. (C) 2000 Elsevier Science B.V. All rights reserved

Bendahl, L.; Sidenius, U.

2000-01-01

 
 
 
 
301

Monitoring of Pesticides Residues in Italian Mineral Waters by Solid Phase Extraction and Gas Chromatography Mass Spectrometry  

Directory of Open Access Journals (Sweden)

Full Text Available Twenty-two pesticides and metabolites, selected on the basis of regional priority lists, were surveyed in thirty Italian mineral waters springs for three years by a procedure based on solid phase extraction in combination with gas chromatography coupled with mass spectrometry detection. The procedure proved to be simple, sensitive and reliable, the limits of detection and relative standard deviations were respectively in the range of 0.002 - 0.04 ?g/L and 3% - 7%, recoveries ranged from 86% to 105% at the European Union Maximum Acceptable Concentration (MAC. Pesticide residues were detected in just one of the ninety water samples analyzed but no one exceeding the MAC. These results demonstrate the good quality of Italian mineral waters, not forgetting the need of constant revision and update of the priority list of pollutants.

Anna Maria Tarola

2012-10-01

302

Determination of fipronil in bovine plasma by solid-phase extraction and liquid chromatography with ultraviolet detection  

Directory of Open Access Journals (Sweden)

Full Text Available A fast and efficient method has been developed and validated for the determination of fipronil in bovine plasma. Samples were subjected to solid-phase extraction (SPE followed by reversed phase liquid chromatography (LC separation, using acetonitrile/water (60:40 v/v as the mobile phase with a flow rate of 1.0 mL/min and ultraviolet (UV detection at 210 nm. Ethiprole was used as the internal standard (IS. The method was found to be linear over the range 5-500 ng/mL (r = 0.999. The limit of quantitation (LOQ was validated at 5 ng/mL. The method was successfully applied to monitor plasma concentrations following subcutaneous administration of fipronil in cattle.

Yara P. Cid

2012-01-01

303

Colorimetric Solid Phase Extraction for the Measurement of Total I (Iodine, Iodide, and Triiodide) in Spacecraft Drinking Water  

Science.gov (United States)

An experimental drinking water monitoring kit for the measurement of iodine and silver(I) was recently delivered to the International Space Station (ISS). The kit is based on Colorimetric Solid Phase Extraction (CSPE) technology, which measures the change in diffuse reflectance of indicator disks following exposure to a water sample. To satisfy additional spacecraft water monitoring requirements, CSPE has now been extended to encompass the measurement of total I (iodine, iodide, and triiodide) through the introduction of an oxidizing agent, which converts iodide and triiodide to iodine, for measurement using the same indicator disks currently being tested on ISS. These disks detect iodine, but are insensitive to iodide and triiodide. We report here the operational considerations, design, and ground-based performance of the CSPE method for total I. The results demonstrate that CSPE technology is poised to meet NASA's total I monitoring requirements.

Lipert, Robert J.; Porter, Marc D.; Siperko, Lorraine M.; Gazda, Daniel B.; Rutz, Jeff A.; Schultz, John R.; Carrizales, Stephanie M.; McCoy, J. Torin

2009-01-01

304

Determination of enrofloxacin by room-temperature phosphorimetry after solid phase extraction on an acrylic polymer sorbent  

Science.gov (United States)

A phosphorimetric method was developed to enable the determination of enrofloxacin using photochemical derivatization which was used to both improve detection limits and to minimize the uncertainty of measurements. Phosphorescence was induced on cellulose containing TlNO3. Absolute limit of detection at the ng range and linear analytical response over three orders of magnitude were achieved. A metrological study was made to obtain the combined uncertainty value and to identify that the precision was mainly affected by the changing of substrates when measuring the signal from each replicate. Pharmaceutical formulations containing enrofloxacin were successfully analyzed by the method and the results were similar to the ones achieved using a HPLC method. A solid phase extraction on an acrylic polymer was optimized to separate enrofloxacin from interferents such as diclofenac and other components from biological matrices, which allowed the successful use of the method in urine analysis.

de Souza, Cabrini F.; Martins, Renata K. S.; da Silva, Andrea R.; da Cunha, Alessandra L. M. C.; Aucélio, Ricardo Q.

305

ALTERNATIVES TO METHANOL WATER ELUTION OF SOLID-PHASE EXTRACTION COLUMNS FOR THE FRACTIONATION OF HIGH LOG KOW ORGANIC COMPOUNDS IN AQUEOUS ENVIRONMENTAL SAMPLES  

Science.gov (United States)

A toxicity-directed method for fractionating non-polar organic toxicants using solid-phase extraction (SPE) is described in phase II of EPA's "Methods for Aquatic Toxicity Evaluations". his method has been used very successfully to extract and fractionate acutely and chronically ...

306

A method to detect diphenylamine contamination of apple fruit and storages using headspace solid phase micro-extraction and gas chromatography/mass spectroscopy.  

Science.gov (United States)

Analysis of headspace concentrations of diphenylamine using solid phase micro-extraction (SPME) was examined for its suitability to detect DPA contamination and off-gassing in apple (Malus domestica) fruit, storage rooms and storage materials. Four SPME fibre coatings including polydimethylsiloxane (PDMS, 100 ?m), PDMS/divinylbenzene (PDMS/DVB), Polyacrylate (PA) and PDMS 7 ?m were evaluated. The average limits of detection and of quantification for head space DPA ranged from 0.13 to 0.72 ?g L(-1) and 0.42 to 2.35 ?g L(-1), respectively. Polyacrylate was identified to be the most suitable and compatible fibre for DPA analysis in apple samples, because of its high sensitivity to DPA and low fruit volatile interferences. SPME techniques were further applied to study contamination of DPA in apples, storage rooms and packaging materials. DPA was found in the air of storage rooms containing apples that were not treated with DPA. Wood and plastic bin material, bin liners, and foam insulation all adsorbed and off-gassed DPA and could be potential sources of contamination of untreated apples. PMID:24799236

Song, Jun; Forney, Charles F; Jordan, Michael A

2014-10-01

307

Determination of atrazine and its major degradation products in soil pore water by solid-phase extraction, chemical derivatization, and gas chromatography/mass spectrometry  

Science.gov (United States)

This report describes a method for the determination of atrazine, desethylatrazine, deisopropylatrazine, didealkylatrazine, and hydroxyatrazine from soil pore waters by use of solid-phase extractionfollowed by chemical derivatization and gas chromatography/mass spectrometry. The analytes are isolated from the pore-water matrix byextraction onto a graphitized carbon-black cartridge. The cartridge is dried under vacuum, and adsorbed analytes are removed by elution with ethyl acetate followed by dichloromethane/methanol (7:3, volume/volume). Water is removed from the ethyl acetate fraction on an anhydrous sodium sulfate column. The combined fractions are solvent exchanged into acetonitrile, evaporated by use of a nitrogen stream, and derivatized by use of N- methyl-N-(tert-butyldimethylsilyl)- trifluoroacetamide. The derivatized extracts are analyzed by capillary-column gaschromatography/electron-impact mass spectrometry in the scan mode. Estimated method detection limits range from 0.03 to 0.07 micrograms per liter. The mean recoveries of all analytes and surrogates determined at 0.74 to 0.82 micrograms per liter in reagent water in soil pore water were 94 percent and 98 percent, respectively. The mean recoveries of all analytes and surrogates determined at 7.4 to 8.2 micrograms per liter in reagent water and in soil pore water were 96 percent and 97 percent,respectively. Recoveries were 90 percent or higher, regardless of analyte concentration or matrix composition, for all compounds excepthydroxyatrazine, whose recoveries were slightly lower (77 percent) at the low concentration.

Carter, D.S.

1996-01-01

308

Determination of alachlor and its sulfonic acid metabolite in water by solid-phase extraction and enzyme-linked immunosorbent assay  

Science.gov (United States)

Solid-phase extraction (SPE) and enzyme-linked immunosorbent assay (ELISA) were combined for the trace analysis of the herbicide alachlor and its major soil metabolite, ethanesulfonic acid (ESA). The anti-alachlor antibody cross-reacted with ESA, which produced false-positive detections of alachlor in water samples by immunoassay screens. Alachlor and ESA were isolated from water by SPE on a C18 resin and eluted sequentially with ethyl acetate and methanol. Alachlor is soluble in ethyl acetate while the anionic ESA is not. Thus ESA remained adsorbed on the C18 resin and was eluted later with methanol. The combination of SPE with ELISA effectivety separated and quantified both alachlor and ESA using the same antibody for two ELISA methods. The general method may have applicability for the separation of other herbicides and their ionic metabolites. The SPE-ELISA method has a, detection limit of 0.01 ??g/L for alachlor and 0.05 ??g/L for ESA, with a precision of ?? 10%. Analyses of surface and ground water samples were confirmed by gas chromatography/mass spectrometry and high-performance liquid chromatography with photodiode-array detection. Results showed widespread occurrence of ESA in surface and ground water of the midwestern United States, with concentrations ranging from 10 ??g/L.

Aga, D.S.; Thurman, E.M.; Pomes, M.L.

1994-01-01

309

Acrylamide-modified graphene for online micro-solid-phase extraction coupled to high-performance liquid chromatography for sensitive analysis of heterocyclic amines in food samples.  

Science.gov (United States)

Heterocyclic amines (HAs) are considered as potential mutagens and carcinogens, and are found in trace quantities (ng/g level) in food samples. Therefore, it is important to develop a selective and effective method to determine trace HAs in complex matrices. In this study, acrylamide-modified graphene (AMG) was successfully synthesised and showed good stability and permeability in aqueous and organic phases. AMG was used as an efficient adsorbent in the online micro-solid-phase extraction (?-SPE) of trace HAs. The enrichment factors of the AMG ?-SPE column were determined as 78-166 for six HAs. An online method based on AMG ?-SPE coupled to high-performance liquid chromatography was developed. The limits of detection ranged from 0.70 to 2.5ng/L. Trace HAs in spicy salted duck, baked fish, and fried chicken samples were determined and the concentrations of 2-amino-3-methylimidazo[4,5-f]quinoine, 2-amino-3,4-dimethylimidazo[4,5-f]quinoine, and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline in these samples were 4.7-37.3, 8.1-15.4, and 43.3-109ng/g, respectively. The recoveries for the six HAs ranged from 65.9% to 118%, and the relative standard deviation (RSDs) were less than 10.8%. The proposed online method was sensitive, reliable, and convenient for the analysis of trace HAs in food samples. PMID:25281083

Zhang, Qianchun; Li, Gongke; Xiao, Xiaohua

2015-01-01

310

Application of dispersive solid-phase extraction and ultra-fast liquid chromatography-tandem quadrupole mass spectrometry in food additive residue analysis of red wine.  

Science.gov (United States)

A novel and effective dispersive solid-phase extraction (dSPE) procedure with rapid magnetic separation using ethylenediamine-functionalized magnetic polymer as an adsorbent was developed. The new procedure had excellent clean-up ability for the selective removal of the matrix in red wine. An accurate, simple, and rapid analytical method using ultra-fast liquid chromatography-tandem quadrupole mass spectrometry (UFLC-MS/MS) for the simultaneous determination of nine food additives (i.e., acesulfame, saccharin, sodium cyclamate, aspartame, benzoic acid, sorbic acid, stevioside, dehydroacetic acid, and neotame) in red wine was also used and validated. Recoveries ranging from 78.5% to 99.2% with relative standard deviations ranging from 0.46% to 6.3% were obtained using the new method. All target compounds showed good linearities in the tested range with correlation coefficients (r) higher than 0.9993. The limits of quantification for the nine food additives were between 0.10 ?g/L and 50.0 ?g/L. The proposed dSPE-UFLC-MS/MS method was successfully applied in the food-safety risk monitoring of real red wine in Zhejiang Province, China. PMID:23044217

Chen, Xiao-Hong; Zhao, Yong-Gang; Shen, Hao-Yu; Jin, Mi-Cong

2012-11-01

311

Fast solid-phase extraction-gas chromatography-mass spectrometry procedure for oil fingerprinting. Application to the Prestige oil spill.  

Science.gov (United States)

A rapid and simple fractionation procedure using solid-phase extraction (SPE) cartridges was developed for an accurate determination of aliphatic and polycyclic aromatic hydrocarbons in petroleum residues and further application in chemical fingerprinting of oil spills by gas chromatography-mass spectrometry (GC-MS). Among the adsorbents evaluated, SiO2/C3-CN exhibited the best selectivity, providing, by elution with n-hexane (4 ml) and n-hexane-CH2Cl2 (1:1) (5 ml), two well-resolved aliphatic and aromatic hydrocarbon fractions, with recoveries of 97 +/- 7.2 and 99.7 +/- 13.9%, respectively. The SPE fractionation procedure was compared with the conventional silica-alumina adsorption chromatography showing similar results but practical advantages in terms of reproducibility, analysis time, solvent reduction and cost. Moreover, is particularly suitable for routine analysis with a high sample throughput. The developed methodology was tested in the characterization of fuel-oil samples collected along the Spanish north-west coast, after the Prestige oil spill accident. PMID:14753680

Alzaga, Roberto; Montuori, Paolo; Ortiz, Laura; Bayona, Josep M; Albaigés, Joan

2004-01-30

312

Synthesis, characterization and application of ethylenediamine-modified multiwalled carbon nanotubes for selective solid-phase extraction and preconcentration of metal ions  

Energy Technology Data Exchange (ETDEWEB)

A new method that utilizes ethylenediamine-modified multiwalled carbon nanotubes as a solid-phase extractant has been developed for simultaneous preconcentration of trace Cr(III), Fe(III) and Pb(II) prior to the measurement by inductively coupled plasma optical emission spectrometry. Identification of the surface modification was characterized and performed on the basis of transmission electron microscopy, Fourier transform infrared spectra and elemental analysis. The separation/preconcentration conditions of analytes were investigated, including the pH value, the shaking time, the sample flow rate and volume, the elution condition and the interfering ions. The maximum adsorption capacity of the adsorbent at optimum conditions was found to be 39.58, 28.69 and 54.48 mg g{sup -1} for Cr(III), Fe(III) and Pb(II), respectively. The detection limits of the method were under 0.35 ng mL{sup -1} and the relative standard deviations were lower than 3.5% (n = 11). The method was validated using a certified reference material, and has been applied for the determination of trace Cr(III), Fe(III) and Pb(II) in biological and natural water samples with satisfactory results.

Zang Zhipeng; Hu Zheng; Li Zhenhua; He Qun [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Chang Xijun, E-mail: li_zhh06@lzu.cn [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China)

2009-12-30

313

Assessment of a new method for the analysis of decomposition gases of polymers by a combining thermogravimetric solid-phase extraction and thermal desorption gas chromatography mass spectrometry.  

Science.gov (United States)

For analysis of the gaseous thermal decomposition products of polymers, the common techniques are thermogravimetry, combined with Fourier transformed infrared spectroscopy (TGA-FTIR) and mass spectrometry (TGA-MS). These methods offer a simple approach to the decomposition mechanism, especially for small decomposition molecules. Complex spectra of gaseous mixtures are very often hard to identify because of overlapping signals. In this paper a new method is described to adsorb the decomposition products during controlled conditions in TGA on solid-phase extraction (SPE) material: twisters. Subsequently the twisters were analysed with thermal desorption gas chromatography mass spectrometry (TDS-GC-MS), which allows the decomposition products to be separated and identified using an MS library. The thermoplastics polyamide 66 (PA 66) and polybutylene terephthalate (PBT) were used as example polymers. The influence of the sample mass and of the purge gas flow during the decomposition process was investigated in TGA. The advantages and limitations of the method were presented in comparison to the common analysis techniques, TGA-FTIR and TGA-MS. PMID:24929909

Duemichen, E; Braun, U; Senz, R; Fabian, G; Sturm, H

2014-08-01

314

Determining plasma morphine levels using GC-MS after solid phase extraction to monitor drug levels in the postoperative period  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english OBJECTIVE: To implement a selective and sensitive analytical method to quantify morphine in small volumes of plasma by gas-liquid chromatography-mass spectrometry (GC-MS), aimed at post-operatively monitoring the drug. METHOD: A gas-liquid chromatographic method with mass detection has been develope [...] d to determine morphine concentration in plasma after solid phase extraction. Morphine-d3 was used as an internal standard. Only 0.5 mL of plasma is required for the drug solid-phase extraction in the Bond Elut-Certify®, followed by the quantification of morphine derivative by GC-MS using a linear temperature program, a capillary fused silica column, and helium as the carrier and make-up gas. The method was applied to determine morphine content in plasma samples of four patients during the postoperative period of cardiac surgery. Patient-controlled analgesia with morphine was performed by a venous catheter, and a series of venous blood samples were collected. After the oro-After the orotracheal extubation, morphine plasma levels were monitored for up to 36 hours. RESULTS: The run time was 16 minutes because morphine and the internal standard were eluted after 8.8 minutes. The GC-MS method had 0.5 -1000 ng/mL linearity range (r²=0.9995), 0.1 ng/mL limit of detection, intraday and interday precision equivalent to 1.9% and 6.8%, and 0.1% and 0.8% systematic error (intraday and interday, respectively). The analytical method showed optimal absolute (98%) and relative (100.7%) recoveries. Morphine dose requirements and plasma levels are discussed. CONCLUSION: The analytical gas-liquid chromatography-mass spectrometry method is selective and adequate for morphine measurements in plasma for applications in clinical studies.

Veronica, Santos; Karin Jannet Vera, López; Luciana Moraes, Santos; Mauricio, Yonamine; Maria José Carvalho, Carmona; Silvia Regina Cavani Jorge, Santos.

315

Determining plasma morphine levels using GC-MS after solid phase extraction to monitor drug levels in the postoperative period  

Directory of Open Access Journals (Sweden)

Full Text Available OBJECTIVE: To implement a selective and sensitive analytical method to quantify morphine in small volumes of plasma by gas-liquid chromatography-mass spectrometry (GC-MS, aimed at post-operatively monitoring the drug. METHOD: A gas-liquid chromatographic method with mass detection has been developed to determine morphine concentration in plasma after solid phase extraction. Morphine-d3 was used as an internal standard. Only 0.5 mL of plasma is required for the drug solid-phase extraction in the Bond Elut-Certify®, followed by the quantification of morphine derivative by GC-MS using a linear temperature program, a capillary fused silica column, and helium as the carrier and make-up gas. The method was applied to determine morphine content in plasma samples of four patients during the postoperative period of cardiac surgery. Patient-controlled analgesia with morphine was performed by a venous catheter, and a series of venous blood samples were collected. After the oro-After the orotracheal extubation, morphine plasma levels were monitored for up to 36 hours. RESULTS: The run time was 16 minutes because morphine and the internal standard were eluted after 8.8 minutes. The GC-MS method had 0.5 -1000 ng/mL linearity range (r²=0.9995, 0.1 ng/mL limit of detection, intraday and interday precision equivalent to 1.9% and 6.8%, and 0.1% and 0.8% systematic error (intraday and interday, respectively. The analytical method showed optimal absolute (98% and relative (100.7% recoveries. Morphine dose requirements and plasma levels are discussed. CONCLUSION: The analytical gas-liquid chromatography-mass spectrometry method is selective and adequate for morphine measurements in plasma for applications in clinical studies.

Veronica Santos

2008-01-01

316

Determination of several pesticides in water by solid-phase extraction, liquid chromatography and electrospray tandem mass spectrometry.  

Science.gov (United States)

The analysis of pesticides in water samples is a problem of primary concern for quality control laboratories due to the toxicity level of these compounds and their public health risk. In order to evaluate the impact of pesticides in the Lisbon drinking water supply system, following the requirements of the European Union Directive 98/83/EC, we developed and validated an analytical method based on the combination of solid-phase extraction with liquid chromatography and tandem mass spectrometry. In this work, several pesticides were studied: imidacloprid, dimethoate, cymoxanil, carbendazime, phosmet, carbofuran, isoproturon, diuron, methidathion, linuron, pyrimethanil, methiocarbe, tebuconazole and chlorpyrifos. Several parameters of the electrospray source were optimized in order to get the best formation conditions of the precursor ion for each pesticide, namely capillary and extractor voltage, cone voltage, cone gas flow rate and desolvation gas flow rate. After optimization of the collision cell energy of the triple quadrupole, two different precursor ion-product ion transitions were selected for each pesticide, one for quantification and one for qualification, and these ions were monitored under time-scheduled multiple reaction monitoring (MRM) conditions. The selection of specific fragment ions for each pesticide guarantees a high degree of selectivity as well as additional sensitivity to quantify trace levels of these pesticides in water samples. This method showed excellent linearity ranges for all pesticides, with correlation coefficients greater than 0.9989. Determination limits (between 0.0041 and 0.0480 microg/L), precision (RSD <9.18%), accuracy and recovery studies in several water samples using solid-phase extraction were also performed. PMID:17064714

Rodrigues, Alexandre Mourão; Ferreira, Vera; Cardoso, Vitor Vale; Ferreira, Elisabete; Benoliel, Maria João

2007-05-25

317

Metal-organic framework MIL-53(Al) as a solid-phase microextraction adsorbent for the determination of 16 polycyclic aromatic hydrocarbons in water samples by gas chromatography-tandem mass spectrometry.  

Science.gov (United States)

In this paper, the potential applications of metal-organic framework (MOF) materials as fiber coatings for the solid-phase microextraction (SPME) of polycyclic aromatic hydrocarbons (PAHs) in water samples were explored. Fibers coated with MIL-53(Al, Cr, Fe) materials were fabricated by an adhesive method for SPME. The quantitation was performed by gas chromatography-tandem mass spectrometry (GC-MS/MS) using the multiple reaction monitoring mode. Among the three MIL-53(M) coatings, MIL-53(Al) showed the highest extraction efficiency towards PAHs under the current fabrication procedure. Under optimized conditions, the MIL-53(Al)-coated fiber showed good precision (relative standard deviation 0.98) for aqueous solutions containing 16 PAH . The fiber also offered high thermal and chemical stability. The method developed based on MIL-53(Al) SPME-GC-MS/MS was successfully applied in the analysis of real water samples. Based on the simulation results, the PAHs were adsorbed on MIL-53(Al) primarily through the hydrophobic and ?-? interactions between PAHs and the organic linker of the material. The results presented in this paper indicate that water-stable MOF materials have great potential for the SPME of aromatic compounds in water samples. PMID:23042089

Chen, Xiang-Feng; Zang, Hao; Wang, Xia; Cheng, Jian-Guang; Zhao, Ru-Song; Cheng, Chuan-Ge; Lu, Xiao-Qing

2012-11-21

318

Preparation of p-tert[(dimethylamino)methyl]-calix[4]arene functionalized aminopropylpolysiloxane resin for selective solid-phase extraction and preconcentration of metal ions.  

Science.gov (United States)

A new p-tert-[(dimethylamino)methyl]-1,3-bisglyciyl-calix[4]arene functionalized aminopropylpolysiloxane resin (APPS-CA) has been prepared and investigated for selective solid-phase extraction (SPE) of trace Cr (III), Cu (II), Ni (II), Co (II) and Zn (II) prior to their determination by inductively coupled plasma optical emission spectrometry (ICP-OES). The characterization of the surface modification was performed on the basis of FT-IR spectroscopy, elemental analysis and thermal gravimetric analysis. The separation/preconcentration conditions of analytes were investigated, including effect of pH, the shaking time, the sample flow rate and volume, the elution condition, the interfering ions and stability test. At pH 4.0, the maximum adsorption capacity of Cr (III), Cu (II), Ni (II), Co (II) and Zn (II) were 47.2, 34.3, 52.8, 29.8 and 36.4 mg g(-1), respectively. The adsorbed metal ions were quantitatively eluted by 2.0 mL of 0.5 mol L(-1) HCl. Common coexisting ions did not interfere with the separation. According to the definition of International Union of Pure and Applied Chemistry, the detection limits (3 sigma) of this method were found to be 0.58, 0.33, 0.47, 0.61 and 0.14 ng mL(-1) for Cr (III), Cu (II), Ni (II), Co (II) and Zn (II), respectively. The relative standard deviation under optimum conditions is less than 4.0%. The application of this new adsorbent to preconcentration trace Cr (III), Cu (II), Ni (II), Co (II) and Zn (II) of two water samples gave high accurate and precise results. PMID:19398269

Nie, Rong; Chang, Xijun; He, Qun; Hu, Zheng; Li, Zhenhua

2009-09-30

319

Solid-phase extraction and liquid chromatography--mass spectrometry for the determination of free fatty acids in shellfish.  

Science.gov (United States)

A novel analytical protocol for the determination of free fatty acids (FFAs; saturated, monounsaturated and polyunsaturated) in shellfish using electrospray ionisation and liquid chromatography-mass spectrometry (LC-MS) is described. Total lipids were extracted from four commercially important shellfish species using chloroform-methanol in a modification of the traditionally used Bligh and Dyer method. FFAs were recovered from lipidic shellfish extracts by solid-phase extraction (SPE) on an aminopropyl-silica column using a 98:2 v/v diethyl ether (DEE)-acetic acid solution. Ether extracts containing the FFAs were evaporated and reconstituted in 70:30 v/v methanol-chloroform before analysis by LC-MS. The limits of quantification (LOQs) of the method ranged from 60 to 560 microgg(-1) wet weight depending on the different FFAs determined with selected ion monitoring (SIM). Results demonstrate that LC-MS is well suited for identification and quantification of FFAs in shellfish and negates the use of sample derivatisation required in gas chromatographic analysis. PMID:17270196

Lacaze, Jean-Pierre C L; Stobo, Lesley A; Turrell, Elizabeth A; Quilliam, Michael A

2007-03-23

320

Field method for the determination of hexavalent chromium by ultrasonication and strong anion-exchange solid-phase extraction.  

Science.gov (United States)

A simple, fast, sensitive, and economical field method was developed and evaluated for the determination of hexavalent chromium (CrVI) in environmental and workplace air samples. By means of ultrasonic extraction in combination with a strong anion-exchange solid-phase extraction (SAE-SPE) technique, the filtration, isolation, and determination of CrVI in the presence of trivalent chromium (CrIII) and potential interferents was achieved. The method entails (1) ultrasonication in basic ammonium buffer solution to extract CrVI from environmental matrixes; (2) SAE-SPE to separate CrVI from CrIII and interferences; (3) elution/acidification of the eluate; (4) complexation of chromium with 1,5-diphenylcarbazide; and (5) spectrophotometric determination of the colored chromium-diphenylcarbazone complex. Several critical parameters were optimized in order to effect the extraction of both soluble (K2CrO4) and insoluble (PbCrO4) forms of CrVI without inducing CrIII oxidation or CrVI reduction. The method allowed for the dissolution and purification of CrVI from environmental and workplace air sample matrixes for up to 24 samples simultaneously in less than 90 min (including ultrasonication). The results demonstrated that the method was simple, fast, quantitative, and sufficiently sensitive for the determination of occupational exposures of CrVI. The method is applicable for on-site monitoring of CrVI in environmental and industrial hygiene samples. PMID:10079763

Wang, J; Ashley, K; Marlow, D; England, E C; Carlton, G

1999-03-01

 
 
 
 
321

Volatile phytochemical composition of rhizome of ginger after extraction by headspace solid-phase microextraction, petroleum ether extraction and steam distillation extraction  

Directory of Open Access Journals (Sweden)

Full Text Available The sampling techniques headspace solid-phase microextraction (HS-SPME, petrol ether extraction (PEE and steam distillation extraction (SDE were compared for the GC-MS of volatile constituents present in ginger (Zingiber officinale. The effects of different parameters, such as extraction fibers, extraction time, extraction temperature and particle size ranges, on the HS-SPME of rhizome of ginger were investigated. Zingiberene (53.12% were predominant components of ginger samples obtained by HS-SPME whereas those levels were 39.01% in the same samples by PEE and 35.05% in those by SDE, respectively. HS-SPME with polydimethylsiloxane (PDMS fiber was more selective and particularly efficient for the isolation of volatile phytochemical composition and afforded a higher yield of total compounds than PEE and SDE. The specific compound isolated by SPME, which due to effective fiber, was much larger than that isolated by PEE or SDE. HS-SPME is a powerful tool for determining the volatile constitutes present in the traditional Chinese medicines.

Zhannan Yang, Weiping Yang, Quancai Peng, Qiansong He, Yong Feng, Shiqiong Luo, Zhengwen Yu

2009-12-01

322

Selective mixed-bed solid phase extraction of atrazine herbicide from environmental water samples using molecularly imprinted polymer.  

Science.gov (United States)

A novel approach for the selective extraction of organic target compounds from water samples has been developed using a mixed-bed solid phase extraction (mixed-bed SPE) technique. The molecularly imprinted polymer (MIP) particles are embedded in a network of silica gel to form a stable uniform porous bed. The capabilities of this method are demonstrated using atrazine as a model compound. In comparison to conventional molecularly imprinted-solid phase extraction (MISPE), the proposed mixed-bed MISPE method in combination with gas chromatography-mass spectrometry (GC-MS) analysis enables more reproducible and efficient extraction performance. After optimization of operational parameters (polymerization conditions, bed matrix ingredients, polymer to silica gel ratio, pH of the sample solution, breakthrough volume plus washing and elution conditions), improved LODs (1.34 µg L(-1) in comparison to 2.25 µg L(-1) obtained using MISPE) and limits of quantification (4.5 µg L(-1) for mixed-bed MISPE and 7.5 µg L(-1) for MISPE) were observed for the analysis of atrazine. Furthermore, the relative standard deviations (RSDs) for atrazine at concentrations between 5 and 200 µg L(-1) ranged between 1.8% and 6.3% compared to MISPE (3.5-12.1%). Additionally, the column-to-column reproducibility for the mixed-bed MISPE was significantly improved to 16.1%, compared with 53% that was observed for MISPE. Due to the reduced bed-mass sorbent and at optimized conditions, the total amount of organic solvents required for conditioning, washing and elution steps reduced from more than 25 mL for conventional MISPE to less than 2 mL for mixed-bed MISPE. Besides reduced organic solvent consumption, total sample preparation time of the mixed-bed MISPE method relative to the conventional MISPE was reduced from more than 20 min to less than 10 min. The amount of organic solvent required for complete elution diminished from 3 mL (conventional MISPE) to less than 0.4 mL with the mixed-bed technique shows its inherent potential for online operation with an analytical instrument. In order to evaluate the selectivity and matrix effects of the developed mixed-bed MISPE method, it was applied as an extraction technique for atrazine from environmental wastewater and river water samples. PMID:25127575

Zarejousheghani, Mashaalah; Fiedler, Petra; Möder, Monika; Borsdorf, Helko

2014-11-01

323

[Simultaneous determination of 9 heterocyclic aromatic amine in poultry products by solid-phase extraction-high performance liquid chromatography].  

Science.gov (United States)

A method was developed for the simultaneous determination of 9 heterocyclic aromatic amines (HAAs) including 2-amino-3-methylimidazo[4,5-f] quinoline (IQ), 2-amino-3,4-dimethylimidazo[4, 5-f] quinoline (MeIQ), 2-amino-3, 8-dimethylimidazo [4, 5-f] quinoxaline (MeIQx), 2-amino-3, 4, 8-trimethyl-imidazo [4,5-f quinoxaline (4,8-DiMeIQx), 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (PhIP), 3-amino-1 -methyl-5H-pyrido [4, 3-b] indole (Trp-p-2), 3-amino-1, 4-dimethyl-5H-pyrido [4,3-b] indole (Trp-p-1), 9H-pyrido [3,4-b] indole (Norharman), 1-methyl-9H-pyrido 3, 4-b] indole (Harman)) in poultry products using solid-phase extraction-high performance liquid chromatography (SPE-HPLC). The performance of 3 different organic extraction solutions, 2 solid phase extraction (SPE) procedures, three different reversed-phase columns and five different mobile phases were tested for optimizing separation conditions of the 9 HAAs from poultry products. In the end, ethyl acetate was selected as the extraction solution, and the extract was purified with propylsulfonic acid silica (PRS) and C18 SPE columns. The analysis was performed on a TSK-gel ODS-80TM column using a gradient elution with the mobile phases of 0.05 mol/L aqueous acetic acid-ammonium acetate buffer (pH 3.4) and acetonitrile. The results showed that the average recoveries (n = 6) of the 9 HAAs spiked in meat samples at 3 levels ranged from 60.47% to 90.55% with the relative standard deviations (RSDs) between 0.49% and 9.74%, and the limits of detection (LODs, S/N = 3) were in the range of 0.1 - 3.6 microg/kg. The method is simple, rapid, accurate and sensitive enough for the analysis of HAAs in poultry products. PMID:22128739

Shao, Bin; Peng, Zengqi; Yang, Hongsheng; Wu, Guanghong; Yao, Yao; Wan, Kehui

2011-08-01

324

Separation of lanthanum(III) and neodymium(III) by extraction with tributyl phosphate in the presence of a solid phase  

International Nuclear Information System (INIS)

Lanthanum(III) and neodymium(III) extraction from nitric acid solutions with tributyl phosphate in the presence of a solid phase has been studied. The coefficient of neodymium nitrate distribution ? in presence of solid phase has been found to increase with decrease of its concentration in the original solution and increase of lanthanum nitrate concentration. Separation is most pronounced in the neodymium nitrate microregion. A procedure has been proposed for quantitative neodymium extraction form lanthanum nitrate solutions with a neodymium and lanthanum separation coefficient higher than 25

325

SUPERCRITICAL FLUID EXTRACTION OF PARTICULATE AND ADSORBENT MATERIALS  

Science.gov (United States)

The report is a summary of work performed by PNL on the extraction of semivolatile organic materials (SVOCs), for example, polynuclear aromatic compounds, from various adsorbents and environmental matrices, using supercritical fluids (SCFs) as extractants. The results of the work...

326

Solid phase extraction of actinides using polymeric beads impregnated with TODGA  

International Nuclear Information System (INIS)

137Cs is one of the major radionuclides contributing to the activity of the high level waste (HLW) and its separation facilitates the safe disposal of the latter in deep geological repository as vitrified mass. The global inventory of 137Cs was estimated to be around 3.7x1014 kBq in 2010. Due to its long half-life and reasonable gamma energy (661 keV), 137Cs it has potential application as a radiation source in gamma irradiators in the environmental pollution control, food preservation and sterilization of medical accessories. It is, therefore, required to develop efficient separation methods for its recovery from HLW. We have recently reported that solvent system containing calix(4)arene-crown-6 ligands in FS-13 have yielded much improved extraction of radio-cesium as compared to analogous solvent systems containing nitrobenzene as the diluents. Our studies involving four different calix-bis-crown-6 and calix-mono-crown-6 ligands have indicated that calix(4)arene-dibenzo-bis-crown-6 (CBC) ligands were better suited due to more favourable extraction of Cs(I) and radiolytic stability of the ligand. In the present study, we have tried use the developed solvent system for the recovery of radio-cesium (137Cs and 134Cs) from actual high level waste (HLW). The HLW, containing a total activity of 100 Ci/L also contained 3.85 g/L U and 7.09 mg/L Pu which were removed by contacting the waste solution twice with 30% TBP in n-dodecane in a hot-cell facility. The raffinate from the TBP extraction step contained negligible amounts of the actinides and was subsequently contacted four times with 1.0x10-3 M CBC in FS-13 (each time with fresh organic phase) in the hot-cell facility and the extraction results indicated 137Cs to remain in the raffinate out of 15.88 Ci/L suggesting ? 97% extraction in 4 stages. Quantitative extraction can be done by increasing the number of stages. It was interesting to note that none of the other radionuclides, such as 144Ce, 106Ru, 95Zr, 95Nb, 90Y and 90Sr were extracted to any measurable extent. Stripping of the extracted radio-cesium was made possible in four stages by contacting the organic extracts with equal volumes of de-ionized water

327

Sol-gel approach for fabrication of coated anodized titanium wire for solid-phase microextraction: highly efficient adsorbents for enrichment of trace polar analytes.  

Science.gov (United States)

Nanotubular titania film was prepared in situ on titanium wire and was used as the fiber substrate for solid-phase microextraction (SPME) because of its high surface-to-volume ratio, easy preparation, and mechanical stability. Three different functional coatings, ?-cyclodextrin (?-CD), ?-cyclodextrin-co-poly(ethylenepropylene glycol) (?-CD/PEG), and polyethylene glycol (PEG)-based sorbents were chemically bonded to the nanostructured wire surface via sol-gel technology to further enhance the absorbing capability and extraction selectivity. Coupled to gas chromatography-flame ionic detection (GC-FID), the prepared SPME fibers were investigated using diverse compounds. The results indicated that the fibers showed good mechanical strength, excellent thermal stability, and wonderful capacity and selectivity to polar compounds, including polar aromatic compounds, alcohols, and ketones. Combining the superior hydrophilic property of a bonded functional molecule and the highly porous structure of a fiber coating, the prepared PEG-coated SPME fiber showed much higher adsorption affinity to ephedrine and methylephedrine than ?-CD and ?-CD/PEG fibers. The as-established PEG-coated SPME-GC analytical method provided excellent sensitivity (LODs, 0.004 and 0.001 ng mL(-1) for ephedrine and methylephedrine, respectively) and better linear range (0.01-2 000 ?g L(-1)). In addition, it has surprising repeatability and reproducibility. Finally, the present approach was used to analyze ephedrine and methylephedrine from real urine samples, and reliable results were obtained. PMID:24682230

Jia, Jing; Xu, Lili; Wang, Shuai; Wang, Licheng; Liu, Xia

2014-05-01

328

Determination of benzimidazole residues in animal tissue samples by combination of magnetic solid-phase extraction with capillary zone electrophoresis.  

Science.gov (United States)

Benzimidazole drugs (BZDs) comprise a large number of synthetic anthelmintics, which are widely used in food-producing animals for prophylactic and therapeutic purposes. To protect consumers from the risks related to BZDs residues, a simple, rapid, and efficient method for simultaneous determination of ten BZDs in animal tissues samples was developed. This analytical procedure involved extracting samples with magnetic solid-phase extraction (MSPE) using magnetite/silica/poly (methacrylic acid-co-ethylene glycol dimethacrylate) (Fe(3)O(4)/SiO(2)/poly (MAA-co-EGDMA)) magnetic microspheres, and determination by capillary zone electrophoresis (CZE). To improve the sensitivity of the method, we employed the electrokinetic injection with field-amplified sample stacking technique (FASS). Berbine solution was used as internal standard to minimize the fluctuation of analytical results. Under the optimized extraction conditions, good linearities were obtained for the ten BZDs with the correlation coefficients (R(2)) above 0.9920. The limits of detections (LODs) for ten BZDs were 1.05-10.42 ng/g in swine muscle and 1.06-12.61 ng/g in swine liver, respectively. The intra- and inter-day relative standard deviations (RSDs) of the developed method were less than 13.6%. The recoveries of the ten BZDs for the spiked samples ranged from 81.1% to 105.4% with RSDs less than 9.3%. PMID:22284500

Hu, Xi-Zhou; Chen, Ming-Luan; Gao, Qiang; Yu, Qiong-Wei; Feng, Yu-Qi

2012-01-30

329

Tea bag filter paper as a novel protective membrane for micro-solid phase extraction of butachlor in aqueous samples.  

Science.gov (United States)

An innovative, cost-effective, simple, and environmental friendly tea bag filter paper protected micro-solid phase extraction (?-SPE) technique was developed for the first time with the aim to miniaturize and minimize the use of organic solvents for the extraction and determination of butachlor in aqueous samples. The ?-SPE device was produced by packing 3.0 mg of an easily synthesized new sorbent, hydroxyl-functionalized polypyrrole (OH-PPY), inside a small tea bag filter paper sachet (1.0 cm × 0.5 cm) that served as a protective envelope. Both the extraction and desorption procedures were facilitated by sonication. Due to the high porosity and the fast water absorption of the tea bag filter paper, the analyte could easily diffuse through and enhance the interaction with the sorbent. Under the optimized conditions for the GC-ECD and the ?-SPE, the limit of detection (S/N ? 3) was 2.0 ?g L(-1) while the limit of quantitation (S/N ? 10) was 10.0 ?g L(-1). The recoveries of the butachlor spiked at 0.050, 0.10, and 0.50 ?g mL(-1) ranged from 77.9 ± 3.0 to 112.5 ± 2.9%. The proposed method was successfully applied for the determination of butachlor in water samples from paddy cultivation sites. The levels found were from non-detectable to 24.71 ± 0.37 ?g L(-1). PMID:24813982

Pelden, Tshering; Thammaknet, Chongdee; Thavarungkul, Panote; Kanatharana, Proespichaya

2014-01-01

330

Solid-phase extraction of ursolic acid from herb using beta-cyclodextrin-based molecularly imprinted microspheres.  

Science.gov (United States)

A new method was employed to solid-phase extract ursolic acid from Ilex kudingcha C. J. Tseng using molecularly imprinted microspheres (MIMs) as the sorbent. Using a surface molecular imprinting technique, MIMs for ursolic acid were prepared with bonded beta-CD and acrylamide in combination based on functionalized poly(glycidyl methacrylate) microspheres (F-PGMA). Compared with non-MIMs (NIMs), MIMs showed high adsorption capacity, significant selectivity, and good site accessibility for ursolic acid. The maximum static adsorption capacities of the MIMs and NIMs for ursolic acid were 42.5 and 4.9 micromol/g, respectively. Chromatographic analysis shows that ursolic acid and oleanolic acid could be separated well when MIMs were used as the stationary phase of HPLC. The conditions of molecularly imprinted SPE (MISPE) of ursolic acid from the herb extract were optimized using different concentrations of ethanol solutions as loading, washing, and eluting solutions. The successful extraction of ursolic acid by MIMs provided a possible innovative approach to separate ursolic acid from herb. PMID:18844208

Liu, Hanmao; Liu, Chunhai; Yang, Xiaojing; Zeng, Songjun; Xiong, Yuanqin; Xu, Weijian

2008-10-01

331

Rapid magnetic solid-phase extraction for the selective determination of isoflavones in soymilk using baicalin-functionalized magnetic nanoparticles.  

Science.gov (United States)

Most protocols of sample preparation for isoflavone determination in soymilk and other liquid soybean products involves tedious freeze-drying and time-consuming extraction procedures. We report a facile and rapid magnetic solid-phase extraction (MSPE) of isoflavones from soymilk for subsequent high-performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) analysis. The extraction was based on the selective binding of isoflavones to baicalin-functionalized core-shell magnetic nanoparticles (BMNPs). The proposed MSPE-HPLC-MS/MS analytical method had a linear calibration curve in the concentration range from 0.3 to 80 mg/L isoflavones. With the use of calycosin, an isomer of one of the isoflavones targeted as an internal standard, interday (5 days) precisions of the slope and intercept of the calibration curves were found to be in the range between 2.5% and 3.6% (RSD, n = 5). Six isoflavones, that is, daidzein, glycitein, genistein, daidzin, glycitin, and genistin were detected in commercial soymilk samples and quantified by the proposed analytical method. The results indicated that the method was useful for fast determination of isoflavones in soymilk and other liquid soybean products. PMID:23898976

Qing, Lin-Sen; Xue, Ying; Liu, Yi-Ming; Liang, Jian; Xie, Jing; Liao, Xun

2013-08-28

332

SOLID PHASE EXTRACTION OF Cd(II) AND Pb(II) IONS BY A NEW CARBOTHIOAMIDE DERIVATIVE  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english An effective, simple, low cost and accurate sorption-spectrophotometric platform for the extractions and subsequent quantifications of Cd(II) and Pb(II) ions in food and environmental samples has been described in this dissertation. The separation and preconcentration of the analyte ions were accomp [...] lished by solid phase extraction method based on the adsorption of their N-(4-methylphenyl)-2-{[(4-phenyl-5-pyridin-4-yl-H-1,2,4-triazol-3-yl)thio]acetyl} hydrazinecarbothioamide (MFPTAHK) complex on Amberlite XAD-8 resin in a mini column. The developed method was systematically investigated in different set of experimental parameters that influence the separation and preconcentration of Cd(II) and Pb(II) ions. The precision of the method was determined by reproducibility studies and expressed as relative standard deviations (RSD %) which were less than 4% for both analyte ions. The limits of detections (LODs) for Cd(II) and Pb(II) ions based on the three times the standard deviation of the blanks (N:10) were found to be 0.31 ?g L-1 and 0.86 ?g L-1, respectively. The developed SPE procedure was utilized for the simultaneous extraction and determinations of Cd(II) and Pb(II) ions levels in rice, cracked wheat and red lentil as food samples and various water samples.

OZDES, DUYGU; DURAN, CELAL; BAYRAK, HACER; SERENCAM, HUSEYIN; BASRI SENTURK, HASAN.

333

Preparation and application of sulfaguanidine-imprinted polymer on solid-phase extraction of pharmaceuticals from water.  

Science.gov (United States)

The molecularly imprinted polymers (MIPs) with sulfaguanidine as a template, methacrylic acid, 4-vinylpyridine, and 2-hydroxyethyl methacrylate as functional monomers, ethylene glycol dimethacrylate as a cross-linker and 2,2'-azobis-isobutyronitrile as an initiator have been prepared through the cross-link reaction of polymerization. Solid-phase extraction (SPE) procedure for the extraction of sulfaguanidine from water samples using the prepared MIPs and non-imprinted (NIPs) was evaluated. The best MIP in combination with commercial sorbents was applied for simultaneous extraction of eight pharmaceuticals. New SPE cartridges were prepared by combination of optimal produced MIP and Oasis HLB in 6mL of polypropilene SPE reservoir. The developed method which includes new SPE cartridge (MIPMAA-Oasis HLB, 400mg/6mL) and thin-layer chromatography was validated. The method provides a linear response over the concentration range of 0.5-150?g/L, depending on the pharmaceutical with the correlation coefficients>0.9843 in all cases except for norfloxacin (0.9770) and penicillin G procaine (0.9801). Also, the method has revealed low limits of detection (0.25-20?g/L), good precision (intra and inter-day), a relative standard deviation below 15% and recoveries above 95% for all eight pharmaceuticals. The developed method by using newly prepared SPE cartridge has been successfully applied to the analysis of production wastewater samples from pharmaceutical industry. PMID:25281079

Mutavdži? Pavlovi?, Dragana; Nikši?, Korana; Livazovi?, Sara; Brnardi?, Ivan; Anžlovar, Alojz

2015-01-01

334

Quantitation of promethazine and metabolites in urine samples using on-line solid-phase extraction and column-switching  

Science.gov (United States)

A chromatographic method for the quantitation of promethazine (PMZ) and its three metabolites in urine employing on-line solid-phase extraction and column-switching has been developed. The column-switching system described here uses an extraction column for the purification of PMZ and its metabolites from a urine matrix. The extraneous matrix interference was removed by flushing the extraction column with a gradient elution. The analytes of interest were then eluted onto an analytical column for further chromatographic separation using a mobile phase of greater solvent strength. This method is specific and sensitive with a range of 3.75-1400 ng/ml for PMZ and 2.5-1400 ng/ml for the metabolites promethazine sulfoxide, monodesmethyl promethazine sulfoxide and monodesmethyl promethazine. The lower limits of quantitation (LLOQ) were 3.75 ng/ml with less than 6.2% C.V. for PMZ and 2.50 ng/ml with less than 11.5% C.V. for metabolites based on a signal-to-noise ratio of 10:1 or greater. The accuracy and precision were within +/- 11.8% in bias and not greater than 5.5% C.V. in intra- and inter-assay precision for PMZ and metabolites. Method robustness was investigated using a Plackett-Burman experimental design. The applicability of the analytical method for pharmacokinetic studies in humans is illustrated.

Song, Q.; Putcha, L.; Harm, D. L. (Principal Investigator)

2001-01-01

335

In vitro biomonitoring in polar extracts of solid phase matrices reveals the presence of unknown compounds with estrogenic activity.  

Science.gov (United States)

Determination of estrogenic activity has so far mainly concentrated on the assessment of compounds in surface water and effluent. This study is one of the first to biomonitor (xeno-)estrogens in sediment, suspended particulate matter and aquatic organisms. The relatively polar acetone extracts from these solid phase matrices do not contain the well-known estrogenic compounds such as hormones, alkylphenols and phthalates. An in vitro 'estrogen receptor-mediated chemical activated luciferase gene expression' (ER-CALUX) assay was applied to samples from various locations in the Netherlands. Estrogenic activity measured in polar fractions of particulate matter and sediment extracts ranged from below detection limit to up to 4.5 pmol estradiol equivalents (EEQ)/g dry weight. Estrogenic activity in freshwater river sediments was up to five times higher compared to sediments from large lakes and coastal locations. Tissue extracts EEQs were determined in bream (Abramis brama), flounder (Platichthysflesus), freshwater mussels (Dreissena polymorpha) and marine mussels (Mytilus edulis). The highest biota EEQ levels were found in the freshwater zebra mussel (30 pmol EEQ/g lipid). One sample site showed greatly elevated EEQs in sediment and biota, which correlated with effects found in the wild populations of bream. The EEQ activity of the unknown compounds in the polar fraction mostly was much higher than the calculated EEQ levels based on known estrogens in the non-polar fraction (previously published data). PMID:12739871

Legler, J; Leonards, P; Spenkelink, A; Murk, A J

2003-01-01

336

Speciation of bio-available chromium in soils by solid-phase extraction and graphite furnace atomic absorption spectrometry  

International Nuclear Information System (INIS)

Speciation of bio-available chromium in soils was performed using extraction with 0.05 M EDTA followed by strong anionic solid-phase extraction. The step gradient elution technique with 0.1 and 0.5 M NaCl as eluent in sequence was sufficient to separate Cr(III) and Cr(VI) with recoveries of 99.7 and 93.4%, respectively. During the determination of separated chromium species by graphite furnace atomic absorption spectrometry (GFAAS), 10% ammonium nitrate solution was co-injected with the sample to eliminate the interferences from the eluent matrix containing high concentrations of chloride. Linear calibration curves over the range of 0-15 ng mL-1 were obtained with good correlation coefficients (R2 = 0.9976 for Cr(III)EDTA-, and 0.9897 for Cr(VI)). The sum of the chromium species determined after separation was in good agreement with total chromium from EDTA extraction of NIST soil standard SRM2709 (0.688 ?g g-1 Cr(III), 0.127 ?g g-1 Cr(VI), 0.742 ?g g-1 total Cr) and a local soil sample (0.030 ?g g-1 Cr(III), 0 ?g g-1 Cr(VI), 0.053 ?g g-1 total Cr)

337

Hydrophilic interaction liquid chromatography-solid phase extraction directly combined with protein precipitation for the determination of triptorelin in plasma.  

Science.gov (United States)

Peptide drugs play a critical role in therapeutic treatment. However, as the complexity of plasma, determination of peptide drugs using liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a daunting task. To solve this problem, hydrophilic interaction liquid chromatography-solid phase extraction (HILIC-SPE) directly combined with protein precipitation (PPT) was developed for the selective extraction of triptorelin from plasma. The extracts were analyzed by reversed-phase liquid chromatography (RPLC). Proteins, phospholipids and highly polar interferences could be removed from plasma by the efficient combination of PPT, HILIC-SPE and RPLC-MS/MS. This method was evaluated by matrix effect, recovery and process efficiency at different concentration levels (50, 500 and 5,000 ng/mL) of triptorelin. Furthermore, the performance of HILIC-SPE was compared with that of reversed-phase C18 SPE and hydrophilic lipophilic balance (Oasis HLB) SPE. Among them, HILIC-SPE provided the minimum matrix effect (ranging from 96.02% to 103.41%), the maximum recovery (ranging from 80.68% to 90.54%) and the satisfactory process efficiency (ranging from 82.83% to 92.95%). The validated method was successfully applied to determine triptorelin in rat plasma. PMID:24820974

Wang, Jixia; Kong, Song; Yan, Jingyu; Jin, Gaowa; Guo, Zhimou; Shen, Aijin; Xu, Junyan; Zhang, Xiuli; Zou, Lijuan; Liang, Xinmiao

2014-06-01

338

Fast Determination of 22 Pesticides in Rice Wine by Dispersive Solid-Phase Extraction in Combination with GC-MS  

Directory of Open Access Journals (Sweden)

Full Text Available A rapid method was developed for the determination of 22 pesticides in rice wine. The procedure involved an extraction with acetonitrile and a cleanup step using dispersive solid-phase extraction (d-SPE, and primary-secondary amine (PSA and octadecylsilane (ODS were used as sorbents. D-SPE had some advantages over some traditional prepara- tions, especially in time and cost. Both the extraction and cleanup only cost about 15 min per a sample. Then the GC-MS was used for quantitative and qualitative analysis. Matrix-matched standards solution and analyte protectant were compared to decrease the matrix effect, and the former showed a better efficacy. Acceptable linearity was achieved in the range of 0.05 - 0.30 mg/L. After matrix-matched standards calibration, recoveries were between 60 and 140%. For the most of pesticides, precision and repeatability were less than 10% and 16%, respectively. The result indicated that the developed method was suitable for the determination of the multi-pesticides in rice wine.

Zhenghe Xiong

2012-01-01

339

In situ electrochemical solid-phase extraction of anions and cations using polypyrrole and overoxidized sulfonated polypyrrole.  

Science.gov (United States)

A new method for the extraction of both anions and cations is proposed using electro-synthesized polypyrrole (PPy) and overoxidized sulfonated polypyrrole film (OSPPy). In situ anion (chloride, nitrate, sulfate) and cation (calcium, magnesium) uptake and release were examined under controlled potential conditions for prospective applications in electrochemically controlled solid-phase extraction (EC-SPE). The PPy film was used as an anode (anion-exchanger) and OSPPy film was used as a cathode (cation-exchanger) material and reverse order of the electrodes were investigated in EC-SPE. This new cell arrangement containing two ion exchanger polymer electrodes was developed to provide in situ removal of both anions and cations from aqueous solution. Simple preparation of the film coatings on a platinum plate was possible using a constant potential method. Applied positive and negative potentials facilitated the in situ extraction and desorption of ions, respectively. Both anions and cations were desorbed into sample aliquot and were determined by ion chromatography (IC). The method was validated using a standard reference material and tested for the determination of the ions in real water samples. PMID:18371893

Sahin, Yücel; Ercan, Betül; Sahin, Mutlu

2008-04-15

340

SOLID PHASE EXTRACTION OF Cd(II) AND Pb(II) IONS BY A NEW CARBOTHIOAMIDE DERIVATIVE  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english An effective, simple, low cost and accurate sorption-spectrophotometric platform for the extractions and subsequent quantifications of Cd(II) and Pb(II) ions in food and environmental samples has been described in this dissertation. The separation and preconcentration of the analyte ions were accomp [...] lished by solid phase extraction method based on the adsorption of their N-(4-methylphenyl)-2-{[(4-phenyl-5-pyridin-4-yl-H-1,2,4-triazol-3-yl)thio]acetyl} hydrazinecarbothioamide (MFPTAHK) complex on Amberlite XAD-8 resin in a mini column. The developed method was systematically investigated in different set of experimental parameters that influence the separation and preconcentration of Cd(II) and Pb(II) ions. The precision of the method was determined by reproducibility studies and expressed as relative standard deviations (RSD %) which were less than 4% for both analyte ions. The limits of detections (LODs) for Cd(II) and Pb(II) ions based on the three times the standard deviation of the blanks (N:10) were found to be 0.31 ?g L-1 and 0.86 ?g L-1, respectively. The developed SPE procedure was utilized for the simultaneous extraction and determinations of Cd(II) and Pb(II) ions levels in rice, cracked wheat and red lentil as food samples and various water samples.

DUYGU, OZDES; CELAL, DURAN; HACER, BAYRAK; HUSEYIN, SERENCAM; HASAN, BASRI SENTURK.

2204-22-01

 
 
 
 
341

Pesticide residue analysis in cereal-based baby foods using multi-walled carbon nanotubes dispersive solid-phase extraction.  

Science.gov (United States)

In the present study, a new analytical method has been developed for the simultaneous quantification of 15 organophosphorus pesticides, including some of their metabolites, (disulfoton-sulfoxide, ethoprophos, cadusafos, dimethoate, terbufos, disulfoton, chlorpyrifos-methyl, malaoxon, fenitrothion, pirimiphos-methyl, malathion, chlorpyrifos, terbufos-sulfone, disulfoton-sulfone and fensulfothion) in three different types of commercial cereal-based baby foods. Dispersive solid-phase extraction (dSPE) with multi-walled carbon nanotubes (MWCNTs) was used together with gas chromatography with nitrogen phosphorus detection. Most favorable conditions involved a previous ultrasound-assisted extraction of the sample with acetonitrile containing formic acid. After evaporation of the extract and redissolution in water, a dSPE procedure was carried out with MWCNTs. The whole method was validated in terms of repeatability, linearity, precision and accuracy and matrix effect was also evaluated. Absolute recoveries were in the range 64-105 % with relative standard deviation values below 7.6 %. Limits of quantification achieved ranged from 0.31 to 5.50 ?g/kg, which were lower than the European Union maximum residue limits for pesticide residues in cereal-based baby foods. PMID:22623047

González-Curbelo, Miguel Angel; Asensio-Ramos, María; Herrera-Herrera, Antonio V; Hernández-Borges, Javier

2012-07-01

342

Preparation and evaluation of molecularly imprinted solid-phase micro-extraction fibers for selective extraction of phthalates in an aqueous sample  

International Nuclear Information System (INIS)

A novel molecularly imprinted polymer (MIP) that was applied to a solid-phase micro-extraction (SPME) device, which could be coupled directly to gas chromatograph and mass spectrometer (GC/MS), was prepared using dibutyl phthalate (DBP) as the template molecule. The characteristics and application of this fiber were investigated. Electron microscope images indicated that the MIP-coated solid-phase micro-extraction (MI-SPME) fibers were homogeneous and porous. The extraction yield of DBP with the MI-SPME fibers was higher than that of the non-imprinted polymer (NIP)-coated SPME (NI-SPME) fibers. The MI-SPME fibers had a higher selectivity to other phthalates that had similar structures as DBP. A method was developed for the determination of phthalates using MI-SPME fibers coupled with GC/MS. The extraction conditions were optimized. Detection limits for the phthalate samples were within the range of 2.17-20.84 ng L-1. The method was applied to five kinds of phthalates dissolved in spiked aqueous samples and resulted in recoveries of up to 94.54-105.34%, respectively. Thus, the MI-SPME fibers are suitable for the extraction of trace phthalates in complicated samples.

343

Removal of cesium and strontium from nuclear wastes using solid phase extraction membranes  

International Nuclear Information System (INIS)

Battelle Pacific Northwest Laboratory (PNL), Westinghouse Idaho Nuclear Co. (WINCO), 3M, and IBC Advanced Technologies, Inc. have demonstrated the removal of strontium and cesium from Idaho National Engineering Laboratory (INEL) radioactive acidic waste using 3M web technology. The acidic waste experiments duplicated simulated open-quotes coldclose quotes test results and confirmed selective removal provided by IBC ligand-particles (Sr, Pb) and ion exchange (Cs) membranes. This same technology can be applied to other adsorbents that have been prepared as fine particles, too fine for use in standard ion exchange columns because they would create too much back pressure. The 3M method which was used to incorporate particles into membranes is flexible so that almost any material with an average particle size of 2-80 micrometers can be made into membrane. Therefore, a number of absorbents that could only be made as fine particles can now be utilized. Other absorbents which are large enough for column use can be ground to finer size and incorporated into membranes. They can then be utilized at much higher flow rates to achieve more rapid separations

344

Polymer monoliths with chelating functionalities for solid phase extraction of metal ions from water.  

Science.gov (United States)

Simple devices for the adsorption and preconcentration of metal ions comprising various monolithic polymers have been prepared by in situ polymerization within the 5.5cm long and 5.6mm i.d. polypropylene syringes. Poly(glycidyl methacrylate-co-ethylene dimethacrylate) monolith was modified with ethylenediamine to obtain the chelating material. The poly(butyl methacrylate-co-ethylene dimethacrylate) and poly(lauryl methacrylate-co-ethylene dimethacrylate) monoliths were first photografted with glycidyl methacrylate prior to functionalization with ethylenediamine. Alternatively, other chelating functionalities including poly(ethylene imines) varying in molecular weight and shape (linear and branched) as well as lysozyme were also attached to the monolithic supports. We found that the poly(glycidyl methacrylate-co-ethylene dimethacrylate) monolith functionalized with ethylenediamine exhibited the best chelating properties characterized with rapid adsorption and a capacity of 111.2mg/g (537?mol/g) for Pb(2+), 38.1mg/g (649?mol/g) for Ni(2+), 69.9mg/g (1100?mol/g) for Cu(2+), and 188.9mg/g (3633?mol/g) for Cr(3+). The very fast desorption was then achieved using 1.0mol/L HNO3 as the eluent. An enrichment factor of 300 was observed for metal ions adsorbed from solutions containing 2ppb of the metal. PMID:24745847

Wang, Hongxia; Zhang, Haiyang; Lv, Yongqin; Svec, Frantisek; Tan, Tianwei

2014-05-23

345

Dispersive micro-solid-phase extraction of benzodiazepines from biological fluids based on polyaniline/magnetic nanoparticles composite.  

Science.gov (United States)

In this study, diverse types of Fe3O4 nanocomposites modified by polyaniline, polypyrrole, and aniline-pyrrole copolymer were synthesized through chemical oxidative polymerization process for dispersive-?-solid phase extraction (D-?-SPE) in the presence of various dopants. The results showed that the nanocomposite modified by polyaniline with p-toluene sulfonic acid as a dopant demonstrated higher extraction efficiency for lorazepam (LRZ) and nitrazepam (NRZ). Also the synthesized magnetic sorbents were characterized. The nanocomposite sorbent in combination with high performance liquid chromatography-UV detection was applied for the extraction, preconcentration and determination of lorazepam and nitrazepam in urine and plasma samples. Different parameters influencing the extraction efficiency including: sample pH, amount of sorbent, sorption time, elution solvent and its volume, salt content, and elution time were optimized. The obtained optimal conditions were: sample pH, 6; amount of sorbent, 5mg; sorption time, 5.0min; elution solvent and its volume, 0.5mM cethyltrimethyl ammonium bromide in acetonitrile, 150?L; elution time, 2.0min and without addition of NaCl. The calibration curves were linear in the concentration range of 1-2000?gL(-1). The limits of detection (LODs) were achieved in the range of 0.5-1.8?gL(-1) for NRZ and 0.2-2.0?gL(-1) for LRZ, respectively. The percent of extraction recoveries and relative standard deviations (n=5) were in the range of 84.0-99.0, 6.1-7.8 for NRZ and 90.0-99.0, 4.1-7.0 for LRZ, respectively. Ultimately, the applicability of the method was successfully confirmed by the extraction and determination of NRZ and LRZ in human urine and plasma samples. PMID:25172820

Asgharinezhad, Ali Akbar; Ebrahimzadeh, Homeira; Mirbabaei, Fatemeh; Mollazadeh, Narges; Shekari, Nafiseh

2014-09-24

346

Determination of herbicides by solid phase extraction gas chromatography-mass spectrometry in drinking waters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Asolid phase extraction (SPE) method has been optimized for the gas chromatography–mass spectrometry (GC–MS) simultaneous determination of herbicides belonging to the following different families: carbamate (molinate), atrazines (atrazine, propazine, simazine, ametryne, cyanazine, terbutylazine, deethylterbutylazine, deethylatrazine), dinitroaniline (trifluralin, pendimethalin), chloroacetamide (alachlor, metolachlor). Different solid substrates have been compared (C18, cyano, st...

Sarzanini, Corrado; Bruzzoniti, Maria Concetta

2006-01-01

347

Micro-column solid phase extraction to determine uranium and thorium in environmental samples  

International Nuclear Information System (INIS)

Extraction chromatographic separation techniques based on U/TEVA and TEVA resins were utilized to separate uranium and thorium isotopes in complex matrices from environmental samples. This approach has the advantages of ease of quantitative analysis, small sample size, an absence of mixed waste solvents, complete separation of U/Th isotopes, acceptable chemical yields and good energy resolution in the alpha spectrum. The procedure for analyzing alpha-emitting isotopes of uranium and thorium in geothermal water from Peito, Taiwan, is illustrated in detail. It involves sample pre-concentration, filtration and separation by highly selective extraction chromatographic resins, followed by electroplating and alpha-spectroscopy. The analytical results show a chemical recovery exceeding 55% for U and 65% for Th, respectively, under optimized conditions. The efficient and cost-effective use of recyclable columns makes the analytical methods simple, accurate, rapid, reliable and robust

348

Novel Solid Phase Extraction and Mass Spectrometry Approaches to Multicomponent Analyses in Complex Matrices  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Analysis of compounds present in complex matrices is always a challenge, which can be partly overcome by applying various sample preparation techniques prior to detection. Ideally, the extraction techniques should be as selective as possible, to minimize the concentration of interfering substances. In addition, results can be improved by efficient chromatographic separation of the sample components. The elimination of interfering substances is especially important when utilizing mass spectrom...

Amini, Nahid

2010-01-01

349

Solid phase extraction and reversed-phase high performance liquid chromatography of homidium in animal tissues  

International Nuclear Information System (INIS)

Homidium bromide, an antitrypanosomal drug, has been in use for about 40 years both for chemotherapy and limited chemoprophylaxis but no specific and accurate method for its detection at sub-microgram levels in tissues is available. The HPLC method described uses C18 reversed phase analytical column with UV detection after basic sample extraction and clean-up on a 3 ml cyano Bond Elut disposable extraction column. Drug recoveries of up to 80% were obtained in the extracts. All tissues analysed were from animals treated with 14C labelled homidium at a dose of 1 mg/kg body weight and slaughtered at 14, 21 and 28 days after treatment. Recoveries were determined by comparing radiometric and HPLC results. The advantage of this procedure was that large amounts of samples could be processed especially from tissues with low drug levels. The detection limit was 50 ng per gram wet tissue. This method is simple, fast, accurate and sufficiently sensitive to be used for monitoring drug levels in meat destined for human consumption. (author). 3 refs, 4 figs, 6 tabs

350

Development of colorimetric solid phase extraction (C-SPE) for in-flight monitoring of spacecraft water supplies  

Science.gov (United States)

Colorimetric solid phase extraction (C-SPE) is a sorption-spectrophotometric technique that combines colorimetric reagents, solid phase extraction, and diffuse reflectance spectroscopy to quantify trace analytes in water samples. In C-SPE, a syringe is used to meter a known volume of sample through a membrane impregnated with a selective colorimetric reagent along with any additives required to optimize the complexation of the reagent and analyte. As the sample is passed through the membrane, analytes are extracted and complexed, leading to a detectable change in the optical characteristics of the membrane. The analyte-reagent complex is then quantified directly on the membrane, using a hand-held diffuse reflectance spectrophotometer. This dissertation focuses on the development, ground testing, and microgravity flight demonstration of C-SPE methods to meet the near- and long-term water quality monitoring needs of NASA. To this end, the ability of C-SPE to function in a microgravity environment was tested through performance evaluations of methods for the determination of the biocidal agents silver(I) and iodine on the KC-135 microgravity simulator. The biocidal iodine platform was investigated further to determine which iodine species is responsible for the C-SPE signal. Through systematic comparisons of C-SPE results and UV-Visible absorbance studies it was determined that biocidally active I2 is the iodine species complexed by poly(vinylpyrrolidone). The application of C-SPE to additional target water quality parameters is demonstrated through the determination of nickel(II), a metal leachate found in archived water samples from the International Space Station, using dimethylglyoxime. This method introduced a new variation of C-SPE, the quantification of trace analytes based on the collection of an insoluble, colored precipitate. The nickel(II) method was then combined with the method for biocidal silver(I) and a new method to measure sample pH to create a multiplexed C-SPE platform. This invention is presented as an approach to increase the collection of on-orbit water quality data collected without requiring additional crew time. The dissertation is concluded with a summation of the current work and a look at future directions.

Gazda, Daniel Bryan

351

Comparison of liquid-liquid extraction, solid-phase extraction and co-precipitation preconcentration methods for the determination of cadmium, copper, nickel, lead and zinc in seawater  

International Nuclear Information System (INIS)

Three major types of pre-concentration methods were evaluated and optimised for the extraction and determination of Cd, Cu, Ni, Pb and Zn from seawater samples. The traditional APDC/DDDC-Freon liquid-liquid extraction method showed excellent results for a multi-elemental analysis. However, the technique is labour consuming, very sensitive to operational conditions, employs environmentally unsafe and expensive solvents and requires large sample volumes. In the solid phase extraction method, the performances of a traditional Amberlite XAD-4 and a novel Dowex Optipore V-493 were evaluated. Application of Dowex Optipore V-493 resin provided better results at low concentrations than the generally used Amberlite XAD-4 resin using low sample volumes. However, the presence of natural organic compounds may decrease extraction efficiency of both resins for Cu. Thus, a pre-treatment with UV irradiation is advantageous for samples with high organic content. Cobalt co-precipitation methods showed good Cu and Ni recoveries, but gave poor results for Cd at low concentrations. In addition, high sample volumes are required. Both solid phase and co-precipitation methods showed unsatisfactory results in determination of Pb. Finally, a summary of methods advantages are given for choosing the most suitable method

352

Determination of the Antibiotic Oxytetracycline in Commercial Milk by Solid-Phase Extraction: A High-Performance Liquid Chromatography (HPLC) Experiment for Quantitative Instrumental Analysis  

Science.gov (United States)

Trace levels of oxytetracylcine spiked into commercial milk samples are extracted, cleaned up, and preconcentrated using a C[subscript 18] solid-phase extraction column. The extract is then analyzed by a high-performance liquid chromatography (HPLC) instrument equipped with a UV detector and a C[subscript 18] column (150 mm x 4.6 mm x 3.5 [mu]m).…

Mei-Ratliff, Yuan

2012-01-01

353

Solid phase extraction of clenbuterol from plasma using immunoaffinity followed by HPLC.  

Science.gov (United States)

An immuno-extraction column for clenbuterol has been prepared. Optimum conditions for the selective retention and elution of clenbuterol have been developed, based on a modification of our earlier work on morphine, chlortoluron and isoproturon. Clenbuterol could be retained on the immuno-column then eluted in one x one ml fraction using 50% methanol in phosphate buffered saline pH 2. On columns containing antisera (but not to clenbuterol) the clenbuterol was removed in the washing step. HPLC-UV determination gave clean traces. Day-to-day reproducibility was improved by precipitating the plasma proteins with acetonitrile. PMID:10701431

Rashid, B A; Kwasowski, P; Stevenson, D

1999-11-01

354

Analysis of trace contamination of phthalate esters in ultrapure water using a modified solid-phase extraction procedure and automated thermal desorption-gas chromatography/mass spectrometry.  

Science.gov (United States)

The present study was aimed to develop a procedure modified from the conventional solid-phase extraction (SPE) method for the analysis of trace concentration of phthalate esters in industrial ultrapure water (UPW). The proposed procedure allows UPW sample to be drawn through a sampling tube containing hydrophobic sorbent (Tenax TA) to concentrate the aqueous phthalate esters. The solid trap was then demoisturized by two-stage gas drying before subjecting to thermal desorption and analysis by gas chromatography-mass spectrometry. This process removes the solvent extraction procedure necessary for the conventional SPE method, and permits automation of the analytical procedure for high-volume analyses. Several important parameters, including desorption temperature and duration, packing quantity and demoisturizing procedure, were optimized in this study based on the analytical sensitivity for a standard mixture containing five different phthalate esters. The method detection limits for the five phthalate esters were between 36 ng l(-1) and 95 ng l(-1) and recovery rates between 15% and 101%. Dioctyl phthalate (DOP) was not recovered adequately because the compound was both poorly adsorbed and desorbed on and off Tenax TA sorbents. Furthermore, analyses of material leaching from poly(vinyl chloride) (PVC) tubes as well as the actual water samples showed that di-n-butyl phthalate (DBP) and di(2-ethylhexyl) phthalate (DEHP) were the common contaminants detected from PVC contaminated UPW and the actual UPW, as well as in tap water. The reduction of DEHP in the production processes of actual UPW was clearly observed, however a DEHP concentration of 0.20 microg l(-1) at the point of use was still being quantified, suggesting that the contamination of phthalate esters could present a barrier to the future cleanliness requirement of UPW. The work demonstrated that the proposed modified SPE procedure provided an effective method for rapid analysis and contamination identification in UPW production lines. PMID:18342867

Liu, Hsu-Chuan; Den, Walter; Chan, Shu-Fei; Kin, Kuan Tzu

2008-04-25

355

A sensitive method for determining total vanadium in water samples using colorimetric-solid-phase extraction-fiber optic reflectance spectroscopy  

Energy Technology Data Exchange (ETDEWEB)

A selective colorimetric-solid-phase extraction (C-SPE) method for the determination of total vanadium in water samples was developed. This method introduced a new variation of C-SPE. The colour reaction is based on the reaction of vanadium(V) ternary complex formed with 1-(2-Pyridylazo)-2-naphtol (PAN) in the presence hydrogen peroxide (H{sub 2}O{sub 2}). In this technique, the target analytes in samples are extracted onto solid matrix loaded with a colorimetric reagent and then quantified directly on the adsorbent surface by using a miniature fiber optic reflectance spectrometer. The measurements were carried out at a wavelength of 589.4 nm since it yielded the largest divergence different in reflectance spectra before and after reaction with the vanadium. The overall time required for the C-SPE procedure was {approx}20 min. The amount of concentrated V is then determined in a few seconds by using miniature reflectance spectrometer. At the optimal conditions, a calibration curve was constructed, revealing a linear range of 0.05-0.52 mg L{sup -1} and a detection limit as low as 0.01 mg L{sup -1} while the RSD lower than 2.8%. In order to verify the accuracy of the method, a certified reference water samples (TMDA) were analysed and the results obtained were in good agreement with the certified values. The proposed method was applied to the determination of vanadium in tap water, seawater samples with a recovery for the spiked samples in the range of 98-102%.

Filik, Hayati, E-mail: filik@istanbul.edu.tr [Istanbul University, Faculty of Engineering, Department of Chemistry, 34320 Istanbul (Turkey); Yanaz, Zeynep [Istanbul University, Faculty of Engineering, Department of Chemistry, 34320 Istanbul (Turkey)

2009-12-30

356

Forensic analysis of high explosives residues in post-blast water samples employing solid phase extraction for analyte pro-concentration  

International Nuclear Information System (INIS)

Nitro aromatic, nitramine and nitrate ester compounds are a major group of high order explosive or better known as military explosives. Octahydro-1,3,5,7-tetrazocine (HMX), 1,3,5-hexahydro-1,3,5-trinitro triazine (RDX), 2,4,6-trinitro-toluene (TNT), pentaerythritol tetranitrate (PETN) and 2,4-dinitrotoluene (2,4-DNT) are secondary high explosives classified as most commonly used explosives components. There is an increasing demand for pre-concentration of these compounds in water samples as the sensitivity achieved by instrumental analytical methods for these high explosives residues are the main drawback in the application at trace levels for forensic analysis. Hence, a simple cartridge solid phase extraction (SPE) procedure was optimized as the off-line extraction and pre-concentration method to enhance the detection limit of high explosive residues using micellar electrokinetic chromatography (MEKC) and gas chromatography with electron-capture detection (GC-ECD) methods. The SPE cartridges utilized LiChrolut EN as the SPE adsorbent. By emplying pre-concentration using SPE, the detection limits of the target analytes in water sample were lowered by more than 1000 times with good percentage recovery (>87%) for MEKC method and lowered by 120 times with more than 2 % percentage recovery for GC-ECD methods. In order to test the feasibility of the developed method to real cases, post-blast water samples were analyzed. The post-blast water samples which were collected froast water samples which were collected from Baling Bom training range, Ulu Kinta, Perak contained RDX and PETN in the range of 0.05 - 0.17 ppm and 0.0124 - 0.0390 ppm respectively. (author)

357

Valuation of solid phase extraction disks in the determination of pesticide residues in surface and groundwater in Panama  

International Nuclear Information System (INIS)

In Panama large quantities of pesticides are used in agriculture and livestock farming and there is increasing concern about their impact on public health and the environment. Chiriqui is the Province that registers the largest number of producers whose activities have impact on the environment, especially on surface and groundwater. Systematic monitoring programmes are non-existent due, in part, to the high cost of laboratory determination of environmental residues of pesticides. Within the framework of the FAO/IAEA/SIDA Coordinated Research Programme, efforts were focused on evaluating and optimising the use of solid phase extraction C18 membrane disks in the analysis of surface and groundwater samples to determine pesticide residues. Factors studied were the effect of pre-washing and conditioning of the disks, flow rates, concentration level and matrix effects of field samples. Four pesticides, carbofuran, chlorothalonil, ametryn and chlorpyrifos were selected for these tests because preliminary analysis showed their presence in surface and groundwater. The technique significantly reduces the amount of organic solvents used as compared with the liquid-liquid extraction method. Quantifiable detection limits (QL) for the method were found to be 0.003 ?g/L carbofuran, 0.016 ?g/L chlorothalonil, 0.007 ?g/L ametryn and 0.003 ?g/L chlorpyrifos, when using standard spiked solutions. Recovery (%) was high when standard mixtures were used for the test runs but low when real surface water samples were tested, especially for chlorothalonil which was not recovered at all. (author)

358

Determination of Benzo(a)pyrene in Malaysian commercialized coffee powder using solid phase extraction and gas chromatography  

International Nuclear Information System (INIS)

Roasting is a critical process in coffee production as it enables the development of flavor and aroma. Benzo[a]pyrene (BaP) is a non desirable product of incomplete combustion at temperatures between 300 and 600 degree Celsius and may be produced during roasting step. In this study, selected samples of roasted coffee powder were analysed for BaP. Extraction of BaP was achieved using C18 solid phase extraction (SPE) prior to analysis by gas chromatography. Calibration curve prepared with concentrations ranged between 3 - 50 ppm showed good linearity with r = 0.999. The limit of detection (LOD) was 0.25 ppm and the limit of quantification (LOQ) was 0.85 ppm. Recovery of BaP obtained from spiked sample (3 ppm) was 88.7 % with RSD (n=3) of 5.4 %. Benzo[a]pyrene was detected in all samples, at level ranging from 0.14 to 0.62 ppb. (author)

359

Study of an online molecularly imprinted solid phase extraction coupled to chemiluminescence sensor for the determination of trichlorfon in vegetables.  

Science.gov (United States)

This study reports a new online molecularly imprinted solid phase extraction coupled to chemiluminescence for the determination of trichlorfon. This molecularly imprinted polymer (MIP) was prepared through bulk polymerization, in which methacrylic acid (MAA) was used as the functional monomer and ethylene glycol dimethacrylate (EGDMA) as the cross-linker. This novel functionalized material was characterized by FT-IR spectra and adsorption, and it exhibited good recognition and selective ability and fast adsorption-desorption dynamics toward trichlorfon. The factors affecting preconcentration of the analytes and sensitivity of the method are discussed in detail. Under the optimal condition, the linear range of the calibration graph was between 0.02 and 1.0 ng L(-1), and the detection limit was 1 × 10(3) ng L(-1). The blank cucumber samples spiked with trichlorfon at three levels were extracted and determined by the presented method with recoveries ranging from 83.5 to 94.5%, and the results were correlated well with those obtained using gas chromatography. Moreover, this developed method was successfully applied to the quantitative detection of trichlorfon residues in leek samples. PMID:22107158

Meng, Ling; Qiao, Xuguang; Song, Jiaming; Xu, Zhixiang; Xin, Junhong; Zhang, Yue

2011-12-28

360

Determination of penicillin-V in human plasma by high-performance liquid chromatography and solid-phase extraction.  

Science.gov (United States)

A high-performance liquid chromatographic method has been developed for the determination of penicillin-V concentrations between 0.1 and 19 micrograms/ml in human plasma. Penicillin-V was isolated from plasma by solid-phase extraction on a C18/OH cartridge. The extracts were injected onto a reversed-phase HPLC system. A 125 x 4 mm C18 column was used to separate penicillin-V from its main metabolites, 5R- and 5S-penicilloic acid and endogenous compounds. The eluent consisted of 66% 0.02 M phosphoric acid buffer, to which tetrabutylammonium dihydrogenphosphate and 34% acetonitrile were added. The column effluent was monitored by ultraviolet spectrophotometry at 269 nm. Using this method, penicillin-V concentrations in plasma could be determined with an accuracy between -5.4 and 5.2% and a precision between 0.8 and 1.6%. The method has proved to be reliable and was used in bioavailability studies for the development of a new oral penicillin-V formulation. PMID:8998551

Krauwinkel, W J; Volkers-Kamermans, N J

1996-04-26

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