WorldWideScience
 
 
1

[Advances of molecularly imprinted polymers for solid phase extraction].  

UK PubMed Central (United Kingdom)

Recent advances in molecularly imprinted polymers (MIPs) as solid phase adsorbents for chromatographic sample pretreatments are summarized, including solid phase extraction, matrix solid phase dispersion extraction, solid phase microextraction, stir bar sorptive extraction and magnetic material extraction. A number of challenges and possibly effective strategies are discussed. And some perspectives of MIPs based extraction in chromatography are also proposed.

Li J; Wen Y; Chen L

2013-03-01

2

Single-walled carbon nanohorn as new solid-phase extraction adsorbent for determination of 4-nitrophenol in water sample.  

UK PubMed Central (United Kingdom)

Single-walled carbon nanohorn (SWCNH) was developed as new adsorbent for solid-phase extraction using 4-nitrophenol as representative. The unique exoteric structures and high surface area of SWCNH allow extracting a large amount of 4-nitrophenol over a short time. Highly sensitive determination of 4-nitrophenol was achieved by linear sweep voltammetry after only 120s extraction. The calibration plot for 4-nitrophenol determination is linear in the range of 5.0x10(-8) M-1.0x10(-5) M under optimum conditions. The detection limit is 1.1x10(-8) M. The proposed method was successfully employed to determine 4-nitrophenol in lake water samples, and the recoveries of the spiked 4-nitrophenol were excellent (92-106%).

Zhu S; Niu W; Li H; Han S; Xu G

2009-10-01

3

Single-walled carbon nanohorn as new solid-phase extraction adsorbent for determination of 4-nitrophenol in water sample.  

Science.gov (United States)

Single-walled carbon nanohorn (SWCNH) was developed as new adsorbent for solid-phase extraction using 4-nitrophenol as representative. The unique exoteric structures and high surface area of SWCNH allow extracting a large amount of 4-nitrophenol over a short time. Highly sensitive determination of 4-nitrophenol was achieved by linear sweep voltammetry after only 120s extraction. The calibration plot for 4-nitrophenol determination is linear in the range of 5.0x10(-8) M-1.0x10(-5) M under optimum conditions. The detection limit is 1.1x10(-8) M. The proposed method was successfully employed to determine 4-nitrophenol in lake water samples, and the recoveries of the spiked 4-nitrophenol were excellent (92-106%). PMID:19635382

Zhu, Shuyun; Niu, Wenxin; Li, Haijuan; Han, Shuang; Xu, Guobao

2009-06-12

4

Solid phase extraction membrane  

Energy Technology Data Exchange (ETDEWEB)

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

5

Automated solid phase extraction.  

UK PubMed Central (United Kingdom)

An overview is given in this chapter of the main potential benefits of using automated Solid phase Extraction (SPE) in the preparation of food samples for LC-MS analysis, both in terms of quality of results and in terms of performance and productivity. Automated SPE instrumentation is described and a range of application examples are given. The foods used in these applications range from non-fatty vegetables, to more complex vegetables, fish, prawn meat, and water, a vital raw product for the food and beverage industries. In most applications previously reported, the SPE technique was mainly used for sample cleanup prior to analysis. Additional examples are given here in which automated SPE is combined with analyte concentration, analyte derivatization, or addition of liquids such as internal standards to further improve limits of quantitation, selectivity, stability and quality of the analysis.

Helle N; Baden M; Petersen K

2011-01-01

6

Studies of properties of complex carbon-silica adsorbents used in sorption-desorption processes (solid-phase extraction)  

Energy Technology Data Exchange (ETDEWEB)

Adsorption properties of carbon and carbon-silica adsorbents, prepared by n-octanol and glucose pyrolysis and catalytic decomposition of n-butane, have been studied regarding their applicability for the extraction and concentration of phenol, its nitro- and chloro-derivatives and trihalomethanes [THM] from aqueous solutions in the concentration range of 2 to 20 mg/l. The adsorbents investigated have been subjected to various physico-chemical processes (hydrothermal treatment, oxidation, silanization) in order to improve their efficiency. The adsorption isotherms measured correspond well to the Freundlich equation. A good correlation have been observed between the values of the Freundlich constant k and the adsorbent efficiency. The investigation has been carried out using the ``off line`` method, and recovery rates for the compounds studied as high as 40-100% have been obtained. (orig.)

Rudzinski, W. [Maria Curie-Sklodowska Univ., Lublin (Poland). Faculty of Chemistry; Gierak, A. [Maria Curie-Sklodowska Univ., Lublin (Poland). Faculty of Chemistry; Leboda, R. [Maria Curie-Sklodowska Univ., Lublin (Poland). Faculty of Chemistry; Dabrowski, A. [Maria Curie-Sklodowska Univ., Lublin (Poland). Faculty of Chemistry

1995-08-01

7

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

UK PubMed Central (United Kingdom)

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.

Deng M; Jiang C; Jia L

2013-04-01

8

HPLC determination of hesperidin, diosmin and eriocitrin in Iranian lime juice using polyamide as an adsorbent for solid phase extraction.  

UK PubMed Central (United Kingdom)

Solid phase extraction (SPE) and HPLC were used for simultaneous determination of hesperidin, diosmin and eriocitrin in Iranian lime juice samples. The method involved very simple efficient SPE with polyamide cartridge, the use of mixture of water/acetonitrile/acetic acid (78:19:3, v/v) as a mobile phase at a flow rate of 0.8 mL/min and UV detection at 280 nm. Optimum conditions for SPE were achieved using 8 mL water/methanol (85:15, v/v, pH=3) as the washing solution and 4 mL methanol for elution. SPE parameters, such as maximum loading capacity and breakthrough volume, were also determined for each analyte. Good clean-up and high>90% were observed for all analytes. Limits of detection, limits of quantification, linear range, recovery, repeatability of retention times, and peak areas for hesperidin, diosmin and eriocitrin were 0.0283-0.0512 ?g/mL, 0.0857-0.155 ?g/mL, 0.0283-105.0 ?g/mL (R² > 0.99), 93.3-98.1%, 3.2-4.7% and 2.8-3.6%, respectively. The method was applied to analysis of lime juice samples obtained from different locations of Iran.

Saeidi I; Hadjmohammadi MR; Peyrovi M; Iranshahi M; Barfi B; Babaei AB; Dust AM

2011-09-01

9

HPLC determination of hesperidin, diosmin and eriocitrin in Iranian lime juice using polyamide as an adsorbent for solid phase extraction.  

Science.gov (United States)

Solid phase extraction (SPE) and HPLC were used for simultaneous determination of hesperidin, diosmin and eriocitrin in Iranian lime juice samples. The method involved very simple efficient SPE with polyamide cartridge, the use of mixture of water/acetonitrile/acetic acid (78:19:3, v/v) as a mobile phase at a flow rate of 0.8 mL/min and UV detection at 280 nm. Optimum conditions for SPE were achieved using 8 mL water/methanol (85:15, v/v, pH=3) as the washing solution and 4 mL methanol for elution. SPE parameters, such as maximum loading capacity and breakthrough volume, were also determined for each analyte. Good clean-up and high>90% were observed for all analytes. Limits of detection, limits of quantification, linear range, recovery, repeatability of retention times, and peak areas for hesperidin, diosmin and eriocitrin were 0.0283-0.0512 ?g/mL, 0.0857-0.155 ?g/mL, 0.0283-105.0 ?g/mL (R² > 0.99), 93.3-98.1%, 3.2-4.7% and 2.8-3.6%, respectively. The method was applied to analysis of lime juice samples obtained from different locations of Iran. PMID:21683540

Saeidi, Iman; Hadjmohammadi, Mohammad Reza; Peyrovi, Moazameh; Iranshahi, Mehrdad; Barfi, Behruz; Babaei, Adel Beig; Dust, Abolghasem Mohammad

2011-05-20

10

Allantoin as a solid phase adsorbent for removing endotoxins.  

UK PubMed Central (United Kingdom)

In this study we present a simple and robust method for removing endotoxins from protein solutions by using crystals of the small-molecule compound 2,5-dioxo-4-imidazolidinyl urea (allantoin) as a solid phase adsorbent. Allantoin crystalline powder is added to a protein solution at supersaturated concentrations, endotoxins bind and undissolved allantoin crystals with bound endotoxins are removed by filtration or centrifugation. This method removes an average of 99.98% endotoxin for 20 test proteins. The average protein recovery is ?80%. Endotoxin binding is largely independent of pH, conductivity, reducing agent and various organic solvents. This is consistent with a hydrogen-bond based binding mechanism. Allantoin does not affect protein activity and stability, and the use of allantoin as a solid phase adsorbent provides better endotoxin removal than anion exchange, polymixin affinity and biological affinity methods for endotoxin clearance.

Vagenende V; Ching TJ; Chua RJ; Gagnon P

2013-08-01

11

Matrix solid-phase dispersion extraction of sulfonamides from blood.  

UK PubMed Central (United Kingdom)

Matrix solid-phase dispersion extraction was applied to the extraction of sulfadiazine, sulfamerazine, and sulfamethazine from human and animal bloods. The separation and determination of the analytes were carried out by high-performance liquid chromatography. The effects of the types of the dispersion adsorbents and elution solvents were investigated, and the highest recovery was obtained when diatomaceous earth was used as the dispersion adsorbent, while acetone was used as the elution solvent. Under the optimal conditions, the linear range for determining the sulfonamides in blood samples was 0.020-10.0 µg/mL, and the average recoveries of the three sulfonamides were higher than 87.5%.

Zhang Y; Xu X; Liu H; Zhai Y; Sun Y; Sun S; Zhang H; Yu A; Wang Y

2012-02-01

12

Diaion HP-2MG modified with 2-(2,6-dichlorobenzylideneamino) benzenethiol as new adsorbent for solid phase extraction and flame atomic absorption spectrometric determination of metal ions.  

Science.gov (United States)

A solid phase extraction method for enrichment-separation and the determination of cobalt (Co(2+)), copper (Cu(2+)), nickel (Ni(2+)), zinc (Zn(2+)) and lead (Pb(2+)) ions in real samples has been proposed. The influences of some analytical parameters like pH, flow rate, eluent type and interference of matrix ions on recoveries of analytes were optimized. The limits of detection were found in the range of 1.6-3.9 µg L(-1), while preconcentration factor for all understudy metal ions were found to be 166 with loading half time (t 1/2) less than 10 min. The procedure was applied for the enrichment-separation of analyte ions in environmental samples with recoveries higher than 94.8% and relative SD <4.9% (N = 5). PMID:23613484

Ghaedi, M; Montazerozohori, M; Haghdoust, S; Zaare, F; Soylak, M

2013-04-01

13

Diaion HP-2MG modified with 2-(2,6-dichlorobenzylideneamino) benzenethiol as new adsorbent for solid phase extraction and flame atomic absorption spectrometric determination of metal ions.  

UK PubMed Central (United Kingdom)

A solid phase extraction method for enrichment-separation and the determination of cobalt (Co(2+)), copper (Cu(2+)), nickel (Ni(2+)), zinc (Zn(2+)) and lead (Pb(2+)) ions in real samples has been proposed. The influences of some analytical parameters like pH, flow rate, eluent type and interference of matrix ions on recoveries of analytes were optimized. The limits of detection were found in the range of 1.6-3.9 µg L(-1), while preconcentration factor for all understudy metal ions were found to be 166 with loading half time (t 1/2) less than 10 min. The procedure was applied for the enrichment-separation of analyte ions in environmental samples with recoveries higher than 94.8% and relative SD <4.9% (N = 5).

Ghaedi M; Montazerozohori M; Haghdoust S; Zaare F; Soylak M

2013-04-01

14

Polypyrrole hollow fiber for solid phase extraction.  

UK PubMed Central (United Kingdom)

We have developed a solid-phase extraction method based on conductive polypyrrole (PPy) hollow fibers which were fabricated by electrospinning and in situ polymerization. The electrospun poly (e-caprolactone) (PCL) fibers were employed as templates for the in situ surface polymerization of PPy under mechanical stirring or ultrasonication to obtain burr-shaped or smooth fiber shells, respectively. Hollow PPy fibers, achieved by removing the PCL templates, were the ideal sorbents for solid phase extraction of polar compounds due to their inherent multi-functionalities. By using the hollow PPy fibers, two important neuroendocrine markers of behavioural disorders, 5-hydroxyindole-3-acetic acid and homovanillic acid, were successfully extracted. Under the optimized conditions, the absolute recoveries of the above two neuroendocrine markers were 90.7% and 92.4%, respectively, in human plasma. Due to its simplicity, selectivity and sensitivity, the method may be applied to quantitatively analyse the concentrations of polar species in complex matrix samples.

Tian T; Deng J; Xie Z; Zhao Y; Feng Z; Kang X; Gu Z

2012-04-01

15

Evaluation of multi-walled carbon nanotubes as solid-phase extraction adsorbents of pesticides from agricultural, ornamental and forestal soils.  

Science.gov (United States)

A new, simple and cost-effective method based on the use of multi-walled carbon nanotubes (MWCNTs) as solid-phase extraction stationary phases is proposed for the determination of a group of seven organophosphorus pesticides (i.e. ethoprophos, diazinon, chlorpyriphos-methyl, fenitrothion, malathion, chlorpyriphos and phosmet) and one thiadiazine (buprofezin) in different kinds of soil samples (forestal, ornamental and agricultural) using gas chromatography with nitrogen phosphorus detection. Soils were first ultrasound extracted with 10 mL 1:1 methanol/acetonitrile (v/v) and the evaporated extract redissolved in 20 mL water (pH 6.0) was passed through 100 mg of MWCNTs of 10-15 nm o.d., 2-6 nm i.d. and 0.1-10 microm length. Elution was carried out with 20 mL dichloromethane. The method was validated in terms of linearity, precision, recovery, accuracy and selectivity. Matrix-matched calibration was carried out for each type of soil since statistical differences between the calibration curves constructed in pure solvent and in the reconstituted soil extract were found for most of the pesticides under study. Recovery values of spiked samples ranged between 54 and 91% for the three types of soils (limits of detection (LODs) between 2.97 and 9.49 ngg(-1)), except for chlorpyrifos, chlorpyrifos-methyl and buprofezin which ranged between 12 and 54% (LODs between 3.14 and 72.4 ngg(-1)), which are the pesticides with the highest soil organic carbon sorption coefficient (K(OC)) values. Using a one-sample test (Student's t-test) with fortified samples at two concentration levels in each type of soil, no significant differences were observed between the real and the experimental values (accuracy percentages ranged between 87 and 117%). It is the first time that the adsorptive potential of MWCNTs for the extraction of organophosphorus pesticides from soils is investigated. PMID:19591701

Asensio-Ramos, M; Hernández-Borges, J; Borges-Miquel, T M; Rodríguez-Delgado, M A

2009-06-12

16

Evaluation of multi-walled carbon nanotubes as solid-phase extraction adsorbents of pesticides from agricultural, ornamental and forestal soils.  

UK PubMed Central (United Kingdom)

A new, simple and cost-effective method based on the use of multi-walled carbon nanotubes (MWCNTs) as solid-phase extraction stationary phases is proposed for the determination of a group of seven organophosphorus pesticides (i.e. ethoprophos, diazinon, chlorpyriphos-methyl, fenitrothion, malathion, chlorpyriphos and phosmet) and one thiadiazine (buprofezin) in different kinds of soil samples (forestal, ornamental and agricultural) using gas chromatography with nitrogen phosphorus detection. Soils were first ultrasound extracted with 10 mL 1:1 methanol/acetonitrile (v/v) and the evaporated extract redissolved in 20 mL water (pH 6.0) was passed through 100 mg of MWCNTs of 10-15 nm o.d., 2-6 nm i.d. and 0.1-10 microm length. Elution was carried out with 20 mL dichloromethane. The method was validated in terms of linearity, precision, recovery, accuracy and selectivity. Matrix-matched calibration was carried out for each type of soil since statistical differences between the calibration curves constructed in pure solvent and in the reconstituted soil extract were found for most of the pesticides under study. Recovery values of spiked samples ranged between 54 and 91% for the three types of soils (limits of detection (LODs) between 2.97 and 9.49 ngg(-1)), except for chlorpyrifos, chlorpyrifos-methyl and buprofezin which ranged between 12 and 54% (LODs between 3.14 and 72.4 ngg(-1)), which are the pesticides with the highest soil organic carbon sorption coefficient (K(OC)) values. Using a one-sample test (Student's t-test) with fortified samples at two concentration levels in each type of soil, no significant differences were observed between the real and the experimental values (accuracy percentages ranged between 87 and 117%). It is the first time that the adsorptive potential of MWCNTs for the extraction of organophosphorus pesticides from soils is investigated.

Asensio-Ramos M; Hernández-Borges J; Borges-Miquel TM; Rodríguez-Delgado MA

2009-08-01

17

Dodecylbenzene sulfonate-coated magnetite nanoparticles as a new adsorbent for solid phase extraction-spectrophotometric determination of ultra trace amounts of ammonium in water samples.  

UK PubMed Central (United Kingdom)

A new method was proposed for the determination of ammonium based on the preconcentration with dodecylbenzene sulfonate modified magnetite nanoparticles. Ammonium was oxidized to nitrite by hypobromite and then the nitrite produced was determined spectrophotometrically, using sulfabenzamide and N-(1-naphthyl) ethylenediamine after solid phase extraction. The azo dye produced was desorbed by an appropriate small volume of sodium hydroxide prior to the absorbance measurement. The linear calibration graphs were obtained in the concentration range of 0.03-6.00 ng mL(-1) ammonium. The relative standard deviation and recovery percents were 1.0 and 99.0, respectively, for 1.0 ng mL(-1) ammonium, and the limit of detection was 3.2 ng L(-1) ammonium. The interfering effects of a large number of diverse ions on the determination of ammonium were studied. The method was applied to the determination of ammonium in various types of water resources. The results revealed a high efficiency for the recommended ammonium determination method.

Eskandari H; Shariati MR

2011-10-01

18

Matrix solid-phase dispersion extraction of sulfonamides from blood.  

Science.gov (United States)

Matrix solid-phase dispersion extraction was applied to the extraction of sulfadiazine, sulfamerazine, and sulfamethazine from human and animal bloods. The separation and determination of the analytes were carried out by high-performance liquid chromatography. The effects of the types of the dispersion adsorbents and elution solvents were investigated, and the highest recovery was obtained when diatomaceous earth was used as the dispersion adsorbent, while acetone was used as the elution solvent. Under the optimal conditions, the linear range for determining the sulfonamides in blood samples was 0.020-10.0 µg/mL, and the average recoveries of the three sulfonamides were higher than 87.5%. PMID:22298763

Zhang, Yupu; Xu, Xu; Liu, He; Zhai, Yujuan; Sun, Ye; Sun, Shuo; Zhang, Hanqi; Yu, Aimin; Wang, Yinghua

2012-02-01

19

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.

2005-01-01

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 0.2µgL(-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

2013-07-16

 
 
 
 
21

Coordination polymer adsorbent for matrix solid-phase dispersion extraction of pesticides during analysis of dehydrated Hyptis pectinata medicinal plant by GC/MS.  

Science.gov (United States)

The coordination polymer [Zn(BDC)(H(2)O)(2)](n) was tested for extraction of pyrimethanil, ametryn, dichlofluanid, tetraconazole, flumetralin, kresoxim-methyl and tebuconazole from the medicinal plant Hyptis pectinata, with analysis using gas chromatography-mass spectrometry in selected ion monitoring mode (GC/MS, SIM). Experiments carried out at different fortification levels (0.1, 0.5 and 1.0 ?g g(-1)) resulted in recoveries in the range 73-97%, and RSD values were between 5 and 12% for the [Zn(BDC)(H(2)O)(2)](n) sorbent. Detection and quantification limits ranged from 0.02 to 0.07 ?g g(-1) and from 0.05 to 0.1 ?g g(-1), respectively, for the different pesticides studied. The method developed was linear over the range tested (0.04-14.0 ?g g(-1)), with correlation coefficients ranging from 0.9987 to 0.9998. Comparison between [Zn(BDC)(H(2)O)(2)](n) and the commercial phase C(18)-bonded silica showed good performance of the [Zn(BDC)(H(2)O)(2)](n) polymeric sorbent for the pesticides tested. PMID:21111184

Aquino, Adriano; Wanderley, Kaline A; Paiva-Santos, Carlos de Oliveira; de Sá, Gilberto F; Alexandre, Marcelo da R; Júnior, Severino A; Navickiene, Sandro

2010-10-15

22

Coordination polymer adsorbent for matrix solid-phase dispersion extraction of pesticides during analysis of dehydrated Hyptis pectinata medicinal plant by GC/MS.  

UK PubMed Central (United Kingdom)

The coordination polymer [Zn(BDC)(H(2)O)(2)](n) was tested for extraction of pyrimethanil, ametryn, dichlofluanid, tetraconazole, flumetralin, kresoxim-methyl and tebuconazole from the medicinal plant Hyptis pectinata, with analysis using gas chromatography-mass spectrometry in selected ion monitoring mode (GC/MS, SIM). Experiments carried out at different fortification levels (0.1, 0.5 and 1.0 ?g g(-1)) resulted in recoveries in the range 73-97%, and RSD values were between 5 and 12% for the [Zn(BDC)(H(2)O)(2)](n) sorbent. Detection and quantification limits ranged from 0.02 to 0.07 ?g g(-1) and from 0.05 to 0.1 ?g g(-1), respectively, for the different pesticides studied. The method developed was linear over the range tested (0.04-14.0 ?g g(-1)), with correlation coefficients ranging from 0.9987 to 0.9998. Comparison between [Zn(BDC)(H(2)O)(2)](n) and the commercial phase C(18)-bonded silica showed good performance of the [Zn(BDC)(H(2)O)(2)](n) polymeric sorbent for the pesticides tested.

Aquino A; Wanderley KA; Paiva-Santos Cde O; de Sá GF; Alexandre Mda R; Júnior SA; Navickiene S

2010-12-01

23

Solid-phase extraction (SPE) of Iron using Lanthanum Silicate ion exchange  

International Nuclear Information System (INIS)

Solid-phase extraction (SPE) is gaining wide use as an effective and speedy technique which reduces solvent usage, disposal costs and extraction time. The analyte is adsorbed from solution onto a solid adsorbent, which is followed by elution of the analyte with a solvent appropriate for instrumental analysis. However, there is an increasing need for new selective adsorbents to expand the area of this technique. Lanthanum silicate ion exchanger, which shows unusual selectivity elements and in this study, it was employed to develop a SPE method for iron ion. Special experiments such as determination of distribution coefficient for iron ion in different solvent systems have been determined.

2002-01-01

24

Liquid-solid extraction coupled with magnetic solid-phase extraction for determination of pyrethroid residues in vegetable samples by ultra fast liquid chromatography.  

Science.gov (United States)

In this study, liquid-solid extraction coupled with magnetic solid-phase extraction was successfully developed for the extraction of pyrethroid residues in vegetable samples. The analytes were determined by ultra fast liquid chromatography. The pyrethroids were extracted by liquid-solid extraction and then adsorbed onto magnetic adsorbent. Magnetic adsorbent, C18-functionalized ultrafine magnetic silica nanoparticles, was synthesized by chemical coprecipitation, silanization and alkylation. The analytes adsorbed onto the magnetic adsorbent can be simply and rapidly isolated from sample solution with a strong magnet on the bottom of the extraction vessel. The extraction parameters, such as liquid-solid extraction solvent, liquid-solid extraction time, the amount of magnetic adsorbent, magnetic solid-phase extraction time and magnetic solid-phase extraction desorption solvent, were optimized to improve the extraction efficiency. The analytical performances of this method, including linear range, detection limit, precision, and recovery were evaluated. The limits of detection for pyrethroid were between 0.63 and 1.2 ng g(-1). Recoveries obtained by analyzing the four spiked vegetable samples were between 76.0% and 99.5%. The results showed that the present method was a simple, accurate and high efficient approach for the determination of pyrethroids in the vegetable samples. PMID:23953457

Jiang, Chunzhu; Sun, Ying; Yu, Xi; Gao, Yan; Zhang, Lei; Wang, Yuanpeng; Zhang, Hanqi; Song, Daqian

2013-04-12

25

Liquid-solid extraction coupled with magnetic solid-phase extraction for determination of pyrethroid residues in vegetable samples by ultra fast liquid chromatography.  

UK PubMed Central (United Kingdom)

In this study, liquid-solid extraction coupled with magnetic solid-phase extraction was successfully developed for the extraction of pyrethroid residues in vegetable samples. The analytes were determined by ultra fast liquid chromatography. The pyrethroids were extracted by liquid-solid extraction and then adsorbed onto magnetic adsorbent. Magnetic adsorbent, C18-functionalized ultrafine magnetic silica nanoparticles, was synthesized by chemical coprecipitation, silanization and alkylation. The analytes adsorbed onto the magnetic adsorbent can be simply and rapidly isolated from sample solution with a strong magnet on the bottom of the extraction vessel. The extraction parameters, such as liquid-solid extraction solvent, liquid-solid extraction time, the amount of magnetic adsorbent, magnetic solid-phase extraction time and magnetic solid-phase extraction desorption solvent, were optimized to improve the extraction efficiency. The analytical performances of this method, including linear range, detection limit, precision, and recovery were evaluated. The limits of detection for pyrethroid were between 0.63 and 1.2ngg(-1). Recoveries obtained by analyzing the four spiked vegetable samples were between 76.0% and 99.5%. The results showed that the present method was a simple, accurate and high efficient approach for the determination of pyrethroids in the vegetable samples.

Jiang C; Sun Y; Yu X; Gao Y; Zhang L; Wang Y; Zhang H; Song D

2013-09-01

26

Solid phase extraction of food contaminants using molecular imprinted polymers.  

UK PubMed Central (United Kingdom)

Food contamination from natural or anthropogenic sources poses severe risks to human health. It is now largely accepted that continuous exposure to low doses of toxic chemicals can be related to several chronic diseases, including some type of cancer and serious hormonal dysfunctions. Contemporary analytical methods have the sensitivity required for contamination detection and quantification, but direct application of these methods on food samples can be rarely performed. In fact, the matrix introduces severe disturbances, and analysis can be performed only after some clean-up and preconcentration steps. Current sample pre-treatment methods, mostly based on the solid phase extraction technique, are very fast and inexpensive but show a lack of selectivity, while methods based on immunoaffinity extraction are very selective but expensive and not suitable for harsh environments. Thus, inexpensive, rapid and selective clean-up methods, relaying on "intelligent" materials are needed. Recent years have seen a significant increase of the "molecularly imprinted solid phase extraction" (MISPE) technique in the food contaminant analysis. In fact, this technique seems to be particularly suitable for extractive applications where analyte selectivity in the presence of very complex and structured matrices represents the main problem. In this review, several applications of MISPE in food contamination analysis will be discussed, with particular emphasis on the extraction of pesticides, drugs residua, mycotoxins and environmental contaminants.

Baggiani C; Anfossi L; Giovannoli C

2007-05-01

27

Recent developments in matrix solid-phase dispersion extraction.  

UK PubMed Central (United Kingdom)

Matrix solid-phase dispersion is a sample preparation strategy widely applied to solid, semisolid or viscous samples, including animal tissues and foods with a high lipidic content. The process consists in blending the matrix onto a solid support, allowing the matrix cell disruption and the subsequent extraction of target analytes by means of a suitable elution solvent. First introduced in 1989, MSPD employment and developments are still growing because of the feasibility and versatility of the process, as evidenced by the several reviews that have been published since nineties. Therefore, the aim of the present review is to provide a general overview and an update of the last developments of MSPD.

Capriotti AL; Cavaliere C; Giansanti P; Gubbiotti R; Samperi R; Laganà A

2010-04-01

28

Formation of benzoylecgonine isopropyl ester following solid-phase extraction.  

UK PubMed Central (United Kingdom)

In forensic toxicology general alkaline drug screens typically utilize liquid liquid [LLE] or solid phase extraction [SPE] sample preparation techniques. It is expected that different drugs will be detected when a laboratory changes techniques. In this study, when the authors switched from LLE to SPE they were able to detect benzoylecgonine [BE]. Benzoylecgonine isopropyl ester [BEIE] was also detected. Further investigation demonstrated that the BEIE was formed during sample elution with methylene chloride/isopropanol/ammonium hydroxide. BEIE was not detected if methanol/ammonium hydroxide was used as the elution solvent. Analysts should be aware that BEIE is formed in the presence of BE if elution solvents comprise isopropanol and a strong base. Therefore, use of BEIE as an internal standard in such assays will result in inaccurate quantitation of BE.

Juhascik M; Gleba J; Jenkins A

2012-03-01

29

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

UK PubMed Central (United Kingdom)

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.

Bakas I; Oujji NB; Moczko E; Istamboulie G; Piletsky S; Piletska E; Ait-Ichou I; Ait-Addi E; Noguer T; Rouillon R

2012-07-01

30

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

2012-05-19

31

Highly selective solid-phase extraction of trace Pd(II) by murexide functionalized halloysite nanotubes  

Energy Technology Data Exchange (ETDEWEB)

Graphical abstract: Murexide functionalized halloysite nanotubes have been developed to separate and concentrate trace Pd(II) from aqueous samples. Parameters that affected the sorption and elution efficiency were studied in column mode, and the new adsorbent presented high selectivity and adsorption capacity for the solid phase extraction of trace Pd(II). Highlights: Black-Right-Pointing-Pointer Murexide modified halloysite nanotubes as adsorbent has been reported originally. Black-Right-Pointing-Pointer This adsorbent has a unique selectivity for Pd(II) at pH 1.0. Black-Right-Pointing-Pointer This adsorbent had high adsorption capacity for Pd(II). Black-Right-Pointing-Pointer The precision and accuracy of the method are satisfactory. - Abstract: The originality on the high efficiency of murexide modified halloysite nanotubes as a new adsorbent of solid phase extraction has been reported to preconcentrate and separate Pd(II) in solution samples. The new adsorbent was confirmed by Fourier transformed infrared spectra, X-ray diffraction, scanning electron microscope, transmission electron microscope and N{sub 2} adsorption-desorption isotherms. Effective preconcentration conditions of analyte were examined using column procedures prior to detection by inductively coupled plasma-optical emission spectrometry (ICP-OES). The effects of pH, the amount of adsorbent, the sample flow rate and volume, the elution condition and the interfering ions were optimized in detail. Under the optimized conditions, Pd(II) could be retained on the column at pH 1.0 and quantitatively eluted by 2.5 mL of 0.01 mol L{sup -1} HCl-3% thiourea solution at a flow rate of 2.0 mL min{sup -1}. The analysis time was 5 min. An enrichment factor of 120 was accomplished. Common interfering ions did not interfere in both separation and determination. The maximum adsorption capacity of the adsorbent at optimum conditions was found to be 42.86 mg g{sup -1} for Pd(II). The detection limit (3{sigma}) of the method was 0.29 ng mL{sup -1}, and the relative standard deviation (RSD) was 3.1% (n = 11). The method was validated using certified reference material, and has been applied for the determination of trace Pd(II) in actual samples with satisfactory results.

Li Ruijun; He Qun; Hu Zheng; Zhang Shengrui [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, Lanzhou 730000 (China); Zhang Lijun [Faculty of Science and Engineer, Curtin University, Perth, WA 6845 (Australia); Chang Xijun, E-mail: lirj2010@lzu.edu.cn [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, Lanzhou 730000 (China)

2012-02-03

32

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

33

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

2008-01-01

34

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

35

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

36

Applications of monolithic solid-phase extraction in chromatography-based clinical chemistry assays.  

UK PubMed Central (United Kingdom)

Complex matrices, for example urine, serum, plasma, and whole blood, which are common in clinical chemistry testing, contain many non-analyte compounds that can interfere with either detection or in-source ionization in chromatography-based assays. To overcome this problem, analytes are extracted by protein precipitation, solid-phase extraction (SPE), and liquid-liquid extraction. With correct chemistry and well controlled material SPE may furnish clean specimens with consistent performance. Traditionally, SPE has been performed with particle-based adsorbents, but monolithic SPE is attracting increasing interest of clinical laboratories. Monoliths, solid pieces of stationary phase, have bimodal structures consisting of macropores, which enable passage of solvent, and mesopores, in which analytes are separated. This structure results in low back-pressure with separation capabilities similar to those of particle-based adsorbents. Monoliths also enable increased sample throughput, reduced solvent use, varied support formats, and/or automation. However, many of these monoliths are not commercially available. In this review, application of monoliths to purification of samples from humans before chromatography-based assays will be critically reviewed.

Bunch DR; Wang S

2013-04-01

37

Poly-3,4-ethylenedioxythiophene nanoclusters for high effective solid phase extraction.  

UK PubMed Central (United Kingdom)

Solid phase extraction (SPE) has emerged as the widely used technique for sample preparation in the analytical process. Recent research trends of SPE are toward developing novel adsorbents to enrich the analytes simply and effectively. In this study, we proposed the poly-3,4-ethylenedioxythiophene (PEDOT) nanoclusters as the SPE adsorbent. During the application, only a small amount of PEDOT nanoclusters was needed and placed in a pipet tip with glass wool on either side. Without complex preparation, the target analytes could be directly extracted from the sample onto the extraction material and eluted in this lab-in-a-pipet-tip system. The efficiency of this approach was demonstrated by detecting 20 kinds of sulfonamides (SAs) in honey with ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS). All the analytes were detected by multiple reaction monitoring (MRM) mode. The established method was extensively validated by determining the linearity (R(2)?0.991), average recovery (88.4-105.0%) and precision (relative standard deviation ?9.60%). Low detection limits (0.5-4 ?g kg(-1)), wide linearity (10-250 ?g kg(-1)) and short sample pretreatment time (20 min) were achieved under the optimized conditions. The absolute recoveries of the SAs at high level ranged from 71.1% to 91.4%. Due to its simplicity, selectivity and sensitivity, our new method has potential applications in quantitative analysis of the target compounds in complex samples.

Tian T; Zheng S; Ye B; Qu B; Zhao Y; Kang X; Gu Z

2013-02-01

38

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.

2007-09-05

39

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

40

Flame Atomic Absorption Spectrometric Determination of Trace Amounts of Zinc and Thallium in Different Matrixes after Solid Phase Extraction on Modified Multiwalled Carbon Nanotubes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The potential of modified multiwallcd carbon nanotubes, as a solid-phase extraction sorbent for the simultaneous separation and preconcentration of zinc and thallium has been investigated. Zinc and thallium were adsorbed quantitatively onto modified multiwalled carbon nanotubes in the pH range of 3 ...

Sayed Zia Mohammadi

 
 
 
 
41

Highly selective solid-phase extraction of trace Pd(II) by murexide functionalized halloysite nanotubes.  

UK PubMed Central (United Kingdom)

The originality on the high efficiency of murexide modified halloysite nanotubes as a new adsorbent of solid phase extraction has been reported to preconcentrate and separate Pd(II) in solution samples. The new adsorbent was confirmed by Fourier transformed infrared spectra, X-ray diffraction, scanning electron microscope, transmission electron microscope and N(2) adsorption-desorption isotherms. Effective preconcentration conditions of analyte were examined using column procedures prior to detection by inductively coupled plasma-optical emission spectrometry (ICP-OES). The effects of pH, the amount of adsorbent, the sample flow rate and volume, the elution condition and the interfering ions were optimized in detail. Under the optimized conditions, Pd(II) could be retained on the column at pH 1.0 and quantitatively eluted by 2.5 mL of 0.01 mol L(-1) HCl-3% thiourea solution at a flow rate of 2.0 mL min(-1). The analysis time was 5 min. An enrichment factor of 120 was accomplished. Common interfering ions did not interfere in both separation and determination. The maximum adsorption capacity of the adsorbent at optimum conditions was found to be 42.86 mg g(-1) for Pd(II). The detection limit (3?) of the method was 0.29 ng mL(-1), and the relative standard deviation (RSD) was 3.1% (n=11). The method was validated using certified reference material, and has been applied for the determination of trace Pd(II) in actual samples with satisfactory results.

Li R; He Q; Hu Z; Zhang S; Zhang L; Chang X

2012-02-01

42

Highly selective solid-phase extraction of trace Pd(II) by murexide functionalized halloysite nanotubes.  

Science.gov (United States)

The originality on the high efficiency of murexide modified halloysite nanotubes as a new adsorbent of solid phase extraction has been reported to preconcentrate and separate Pd(II) in solution samples. The new adsorbent was confirmed by Fourier transformed infrared spectra, X-ray diffraction, scanning electron microscope, transmission electron microscope and N(2) adsorption-desorption isotherms. Effective preconcentration conditions of analyte were examined using column procedures prior to detection by inductively coupled plasma-optical emission spectrometry (ICP-OES). The effects of pH, the amount of adsorbent, the sample flow rate and volume, the elution condition and the interfering ions were optimized in detail. Under the optimized conditions, Pd(II) could be retained on the column at pH 1.0 and quantitatively eluted by 2.5 mL of 0.01 mol L(-1) HCl-3% thiourea solution at a flow rate of 2.0 mL min(-1). The analysis time was 5 min. An enrichment factor of 120 was accomplished. Common interfering ions did not interfere in both separation and determination. The maximum adsorption capacity of the adsorbent at optimum conditions was found to be 42.86 mg g(-1) for Pd(II). The detection limit (3?) of the method was 0.29 ng mL(-1), and the relative standard deviation (RSD) was 3.1% (n=11). The method was validated using certified reference material, and has been applied for the determination of trace Pd(II) in actual samples with satisfactory results. PMID:22200320

Li, Ruijun; He, Qun; Hu, Zheng; Zhang, Shengrui; Zhang, Lijun; Chang, Xijun

2011-12-02

43

Investigating the potential of metal-organic framework material as an adsorbent for matrix solid-phase dispersion extraction of pesticides during analysis of dehydrated Hyptis pectinata medicinal plant by GC/MS.  

Science.gov (United States)

Metal-organic frameworks aluminum terephthalate MIL-53 and Cu-benzene-1,3,5-tricarboxylate (BTC) were tested for extraction of pyrimethanil, ametryn, dichlofluanid, tetraconazole, flumetralin, kresoximmethyl, and tebuconazole from the medicinal plant Hyptis pectinata, with analysis using GC/MS in the selected ion monitoring mode. Experiments carried out at different fortification levels (0.1, 0.5, and 1.0 microg/g) resulted in recoveries in the range 61 to 107% with RSD values between 3 and 12% for the metal-organic framework materials. Detection and quantification limits ranged from 0.02 to 0.07 and 0.05 to 0.1 microg/g, respectively, for the different pesticides studied. The method developed was linear over the range tested (0.04-20.0 microg/g), with correlation coefficients ranging from 0.9987 to 0.9998. Comparison of MIL-53 and Cu-BTC with C18-bonded silica showed good performance of the MIL-53 metal-organic framework as a sorbent for the pesticides tested. PMID:23175963

Aquino, Adriano; Ferreira, Jordana Alves; Navickiene, Sandro; Wanderley, Kaline A; de Sá, Gilberto F; Júnior, Severino A

44

Investigating the potential of metal-organic framework material as an adsorbent for matrix solid-phase dispersion extraction of pesticides during analysis of dehydrated Hyptis pectinata medicinal plant by GC/MS.  

UK PubMed Central (United Kingdom)

Metal-organic frameworks aluminum terephthalate MIL-53 and Cu-benzene-1,3,5-tricarboxylate (BTC) were tested for extraction of pyrimethanil, ametryn, dichlofluanid, tetraconazole, flumetralin, kresoximmethyl, and tebuconazole from the medicinal plant Hyptis pectinata, with analysis using GC/MS in the selected ion monitoring mode. Experiments carried out at different fortification levels (0.1, 0.5, and 1.0 microg/g) resulted in recoveries in the range 61 to 107% with RSD values between 3 and 12% for the metal-organic framework materials. Detection and quantification limits ranged from 0.02 to 0.07 and 0.05 to 0.1 microg/g, respectively, for the different pesticides studied. The method developed was linear over the range tested (0.04-20.0 microg/g), with correlation coefficients ranging from 0.9987 to 0.9998. Comparison of MIL-53 and Cu-BTC with C18-bonded silica showed good performance of the MIL-53 metal-organic framework as a sorbent for the pesticides tested.

Aquino A; Ferreira JA; Navickiene S; Wanderley KA; de Sá GF; Júnior SA

2012-09-01

45

Analysis of some organochlorine pesticides in seafood samples by solid-phase extraction - gas chromatography  

Energy Technology Data Exchange (ETDEWEB)

The use of the solid-phase extraction technique for the rapid sample preperation of organochlorine pesticides is described. Samples were simultaneously extracted, cleaned, and fractionated by the solid-phase extraction method and a further separation and determination of extracted fractions was carried out by gas chromatography with either an electron capture or a Hall electrolytic conductivity detector. The percent recovery of the extracted seven pesticides was compared to that of the conventional liquid-liquid extraction method. The analytical figures of merit, chromatograms, and statistic data are reported. The application of this method was demonstrated by a real fish sample determination with mass spectra for confirmation of Kepone detection.

Kohler, P.W.; Su, S.Y.

1986-09-01

46

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

UK PubMed Central (United Kingdom)

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%.

Zhang Y; Xu X; Qi X; Gao W; Sun S; Li X; Jiang C; Yu A; Zhang H; Yu Y

2012-01-01

47

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

2011-12-02

48

[Recent applications of solid-phase extraction techniques for analysis of trace residues and contaminants in food].  

UK PubMed Central (United Kingdom)

The determination of trace residues and contaminants in food often requires extensive sample extraction and preparation prior to instrumental analysis. Due to the multiplicity and complexity of food matrices, it is not possible to use only one sample preparation technique. This review introduces the application of some new techniques of solid-phase extraction (SPE) in recent years, such as solid-phase microextraction (SPME), stir-bar sorptive extraction (SBSE), matrix solid-phase dispersion (MSPD), molecularly imprinted solid-phase extraction (MISPE) , immunoaffinity-based solid-phase extraction (IASPE), monolithic solid-phase extraction, carbon nanotube solid-phase extraction, in the analysis of trace residues and contaminants in food. At last, future developments in this field are outlined.

Li G; Ma G

2011-07-01

49

Determining total oil and grease content in wastewater by solid-phase extraction  

Energy Technology Data Exchange (ETDEWEB)

Standard protocol for the determination of oil and grease in industrial and municipal wastewater currently utilizes chlorofluorocarbons (Freons{trademark}) for liquid-liquid extraction. Environmental concern for stratospheric ozone depletion has prompted investigation into alternative methods. EnvirElut{trademark} solid-phase extraction (SPE) columns were developed and evaluated for this analysis. The recovery and variability determined for synthetic samples, fortified with vegetable or used motor oils, were comparable to that expected by liquid-liquid extraction. This presentation reports the results obtained upon comparison of the recovery observed for oil and grease analysis of industrial and municipal wastewater by solid-phase extraction to conventional liquid-liquid extraction procedures using Freon{trademark} 113. Various means of introducing the sample to the solid-phase extraction column, sample elution solvents, and sample drying procedures are explored.

Ferguson, D.M.; Wells, M.J.M. [Tennessee Technological Univ., Cookeville, TN (United States)

1993-12-31

50

Cost analysis of ELISA, solid-phase extraction, and solid-phase microextraction for the monitoring of pesticides in water.  

UK PubMed Central (United Kingdom)

The implementation of a pesticide water monitoring program in South Africa is limited by a lack of financial and analytical resources. A cost analysis of three analytical methods, enzyme-linked immunosorbent assays (ELISA), solid-phase microextraction (SPME), and traditional solid-phase extraction methods (SPE), was conducted. The cost analysis assumed a hypothetical scenario in terms of the sampling area (a grape farming rural region in the Western Cape province of South Africa), sample collection (weekly grab samples collected from eight sites by an environmental health officer in a nearby town), transport of samples (via courier), and analysis (endosulfan and chlorpyrifos analysis conducted by a local higher educational institution laboratory in Cape Town). The cost per sample for the three analytical methods was determined by estimating the annual capital costs, including building and equipment, and recurrent costs, including transport, personnel, supplies, and building operating costs. At the optimal utility of resources, SPME had the lowest cost per sample (US $37), followed by SPE (US $48.50) and ELISA (US $60). Recurrent costs formed the bulk of the costs of all three methods (91-97%). The cost of supplies was particularly high for ELISA (US $34 per sample). The cost per sample estimated for all three methods is substantially lower than those quoted by other laboratories in South Africa. The low cost of SPME is particularly important because of the sensitivity and reliability of this method and the faster output compared to SPE, and SPME is recommended for the long-term monitoring of pesticide pollution.

Dalvie MA; Sinanovic E; London L; Cairncross E; Solomon A; Adam H

2005-05-01

51

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

Science.gov (United States)

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.

Torres-Perea, C.; Muñoz-Rodríguez, D.; Medina-Peralta, S.; Carrera-Figueiras, C.; Moguel-Ordóñez, Y. B.

2013-06-01

52

Rational design and chromatographic evaluation of histamine imprinted polymers optimised for solid-phase extraction of wine samples.  

Science.gov (United States)

This article reports on the computational design, development and application of a molecularly imprinted polymer (MIP) with specific affinity towards histamine. Computational modelling was used to screen a monomer library in order to select the monomers able to form the strongest complex with the target analyte. These were subsequently used for MIP synthesis by radical polymerisation initiated by UV. MIPs were then evaluated by liquid chromatography and solid phase extraction (SPE) and best MIP behaviour was observed when itaconic acid was used as functional monomer. Finally, after optimisation of the polymer composition, MIPs were used as adsorbents for SPE and clean-up of histamine in wine samples. The proposed histamine extraction method with the MIP-SPE cartridge was found to be reproducible (wine extracts. The described methodology is simple and fast and is suitable for the selective histamine extraction and its subsequent quantification by HPLC-DAD from complex matrices such as wine samples. PMID:23953615

Basozabal, Itsaso; Gomez-Caballero, Alberto; Diaz-Diaz, Goretti; Guerreiro, António; Gilby, Stuart; Goicolea, M Aranzazu; Barrio, Ramón J

2013-08-06

53

Regeneration of adsorbed and covalently immobilized antibodies on solid phases for immunoassay.  

UK PubMed Central (United Kingdom)

A technique for the reproducible re-use of antibody-coated solid phases for immunoassays is described. The method based on the dissociation of the antigen-antibody complexes. Two different procedures, using glycine buffer (pH 2.3) or ethanolamine, were developed. More than ten immunoassay cycles can be realized with the same antibody-coated microtitre plates. These procedures were tested with competitive and sandwich immunoassays, monoclonal and polyclonal antibodies, and a commercial immunoassay kit.

Ilchmann D; Helbig D; Göhler H; Stopsack M; Thiele HJ; Hubl W

1990-10-01

54

Magnetic solid-phase extraction and ultrafast liquid chromatographic detection of Sudan dyes in red wines, juices, and mature vinegars.  

UK PubMed Central (United Kingdom)

A nanocomposite of polystyrene-coated magnetic nanoparticles was successfully synthesized and employed as adsorbent for magnetic solid-phase extraction of four Sudan dyes (I, II III, and IV) in red wines, juices, and mature vinegars. The prepared magnetic nanoparticles with highly hydrophobic properties have excellent adsorption capacity for these lipophilic Sudan dyes. Extraction conditions were optimized. Experimental results showed that the recoveries of the four Sudan dyes were very satisfactory when 70 mg of polystyrene-coated magnetic nanoparticles were used and the extraction could be completed within 20 min. It was proved that these magnetic nanoparticles can be reused after an easy washing process. By coupling the magnetic solid-phase extraction with ultrafast liquid chromatography-ultraviolet spectrometry, a rapid, green, effective, and sensitive method for the determination of Sudan dyes was developed. The LOD for Sudan I, Sudan II, Sudan III, and Sudan IV were 0.0039, 0.0063, 0.0057, and 0.017 ng/mL, respectively. Recoveries obtained by analyzing spiked water samples at three concentration levels (0.1, 1.0, and 10.0 ng/mL) were between 76.3 and 96.6%. The intra- and interday RSDs for the analytes were lower than 9.6%.

Yu X; Sun Y; Jiang CZ; Gao Y; Wang YP; Zhang HQ; Song DQ

2012-12-01

55

Optimisation of the membrane-assisted passive sampler and its comparison with solid phase extraction technique  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english A novel membrane-assisted passive sampler was further optimised in the laboratory. It was then compared to the solid phase extraction technique in terms of the extraction efficiency, enrichment factor, detection limit and selectivity in wastewater. The passive sampler was exposed to 3 wastewater samples under laboratory conditions for 3 days. Five hundred millilitres of wastewater was extracted with C18 cartridges. The extr (more) action efficiency of the passive sampler ranged from 4 to 10% while in solid phase extraction it was 40 to 67% for the 3 chlorophenols. In both cases, extraction efficiency was highest for 2,4-dichlorophenol. The low extraction efficiency in the passive sampler supports the idea that it is not an exhaustive extraction technique and does not disturb the chemical equilibrium of the sample. It therefore measures the bioavailable fraction of the compound and can be used for equilibrium sampling and extraction. The obtained enrichment factors from the passive sampler were 89 and 295 for 2-chlorophenol and 2,4-dichlorophenol, respectively. From solid phase extraction, enrichment factors of 102, 113 and 167 were obtained for 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol, respectively. The enrichment factor (~2.5) and sampling rates (~28 µ·h-1) were both low for 4-chlorophenol in wastewater from passive sampler extraction. The calculated sampling rates were found to be 2 604 µ·h-1 for 2-chlorophenol, 1 074 µ·h-1 for 4-chlorophenol and 5 089 µ·h-1 for 2,4-dichlorophenol in spiked deionised water. In wastewater, the sampling rates were found to be 1 544 µ·h-1 for 2-chlorophenol, 28 µ·h-1 for 4-chlorophenol and 5 106 µ·h-1 for 2,4-dichlorophenol. The passive sampler was found to be superior in its selectivity towards the target compounds compared to solid phase extraction technique with C18 sorbent. Chromatograms from solid phase extraction of wastewater contained high peaks of unidentified, potentially interfering compounds, especially in the early part of the chromatogram. In contrast, chromatograms from the passive sampler extraction were very clean. The detection limits of the passive sampler were comparable with that of solid phase extraction and were around 1.5 µg·-1 except for 4-chlorophenol that was high in wastewater (~100 µg·-1).

Nyoni, Hlengilizwe; Chimuka, Luke; Vrana, Branislav; Cukrowska, Ewa; Tutu, Hlanganani

2010-07-01

56

Multiresidue analysis of neonicotinoids by solid-phase extraction technique using high-performance liquid chromatography.  

Science.gov (United States)

For routine monitoring of pesticides, a multiresidue analysis through solid-phase extraction technique and using high-performance liquid chromatography (HPLC) in cotton seed cake (CSC) has been developed. Extraction of fortified samples was carried out with aqueous acetone under vacuum. The concentrated extract was loaded onto the solid-phase extraction units, preconditioned with acetonitrile. The extraction units were then washed with hexane and finally eluted with acetonitrile. The pesticide residues were determined using a multiresidue method by reversed-phase HPLC. The average percentage recoveries were found to range between 65.47% and 110% at spiking levels of 10 to 40 mg/kg. The method developed shows a healthy rate of recovery and can successfully be utilized for the extraction and screening of neonicotinoid residues in CSC. The detection limits for imidacloprid, acetamiprid, and thiacloprid using this method were found to be 5, 10, and 20 mg/kg, respectively. PMID:19421881

Mohan, Chander; Kumar, Yogesh; Madan, Jyotsana; Saxena, Navneet

2009-05-07

57

Multiresidue analysis of neonicotinoids by solid-phase extraction technique using high-performance liquid chromatography.  

UK PubMed Central (United Kingdom)

For routine monitoring of pesticides, a multiresidue analysis through solid-phase extraction technique and using high-performance liquid chromatography (HPLC) in cotton seed cake (CSC) has been developed. Extraction of fortified samples was carried out with aqueous acetone under vacuum. The concentrated extract was loaded onto the solid-phase extraction units, preconditioned with acetonitrile. The extraction units were then washed with hexane and finally eluted with acetonitrile. The pesticide residues were determined using a multiresidue method by reversed-phase HPLC. The average percentage recoveries were found to range between 65.47% and 110% at spiking levels of 10 to 40 mg/kg. The method developed shows a healthy rate of recovery and can successfully be utilized for the extraction and screening of neonicotinoid residues in CSC. The detection limits for imidacloprid, acetamiprid, and thiacloprid using this method were found to be 5, 10, and 20 mg/kg, respectively.

Mohan C; Kumar Y; Madan J; Saxena N

2010-06-01

58

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

59

Solid Phase Extraction: Applications to the Chromatographic Analysis of Vegetable Oils and Fats  

Energy Technology Data Exchange (ETDEWEB)

Applications of solid-phase extraction for the isolation of certain lipid classes prior to chromatographic analysis are given. More information was found for sterols and related compounds, polar phenols and contaminants such as polycyclic aromatic hydrocarbons. Detailed analytical protocols are presented and discussed in many cases. (Author) 120 refs.

Panagiotopoulout, P. M.; Tsimidou, M.

2002-07-01

60

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

UK PubMed Central (United Kingdom)

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.

Chimuka L; van Pinxteren M; Billing J; Yilmaz E; Jönsson JÅ

2011-02-01

 
 
 
 
61

Solid-phase extraction using molecularly imprinted polymers for selective extraction of a mycotoxin in cereals.  

UK PubMed Central (United Kingdom)

The aim of this work was to develop a method for the clean-up of a mycotoxin, i.e. Ochratoxin A (OTA), from cereal extracts employing a new molecularly imprinted polymer (MIP) as selective sorbent for solid-phase extraction (SPE) and to compare with an immunoaffinity column. A first series of experiments was carried out in pure solvents to estimate the potential of the imprinted sorbent in terms of selectivity studying the retention of OTA on the MIP and on a non-imprinted polymer using conventional crushed monolith. The selectivity of the MIP was also checked by its application to wheat extracts. Then, after this feasibility study, two different formats of MIP: crushed monolith and micro-beads were evaluated and compared. Therefore an optimization procedure was applied to the selective extraction from wheat using the MIP beads. The whole procedure was validated by applying it to wheat extract spiked by OTA at different concentration levels and then to a certified contaminated wheat sample. Recoveries close to 100% were obtained. The high selectivity brought by the MIP was compared to the selectivity by an immunoaffinity cartridge for the clean-up of the same wheat sample. The study of capacity of both showed a significant higher capacity of the MIP.

Ali WH; Derrien D; Alix F; Pérollier C; Lépine O; Bayoudh S; Chapuis-Hugon F; Pichon V

2010-10-01

62

The application of fully automated on-line solid phase extraction in bioanalysis.  

UK PubMed Central (United Kingdom)

This paper describes the application of fully automated on-line solid phase extraction to the bioanalysis of three example compounds using the Symbiosis platform. The on-line assay performance is compared to off-line methodologies for the same compounds. The three example compounds possess a variety of physicochemical properties and different extraction modes were applied in off-line methods. These methods were developed through optimisation of solid phase or liquid-liquid extraction and chromatographic separation conditions for each of the analytes. Both on-line and off-line methods were evaluated for linearity, carryover, imprecision and inaccuracy. Experiments were also performed investigating modification of ionisation and selectivity against different batches of plasma. On-line and off-line methods were found to be comparable in performance. In conclusion, on-line methodology has distinct advantages for the analysis of large numbers of samples with a marked reduction in manual operation.

Mitchell RJ; Christian R; Hughes H; Miah A; Walker DK

2010-05-01

63

Ultrasonic assisted extraction combined with titanium-plate based solid phase extraction for the analysis of PAHs in soil samples by HPLC-FLD.  

UK PubMed Central (United Kingdom)

In this work, ultrasonic assisted extraction combined with solid phase extraction (SPE) was applied in the analysis of polycyclic aromatic hydrocarbons (PAHs) in environment samples. A titania nanotubes/titanium plate was modified with n-octadecanethiol monolayer-protected Ag nanoparticles, and developed as the adsorbent in SPE of PAHs. Six different PAHs in soil samples were analyzed with high performance liquid chromatography-fluorescence detection. The experiment conditions including the deposition time of Ag nanoparticles, extraction solvent properties, the amount of extraction solvent, the amount of organic modifier, extraction time, and desorption solvent properties were optimized. Under the optimized conditions, good linearity and low limits of detection of 0.0015-0.4 ng g(-1) were obtained. The analysis of PAHs in real soil samples gave satisfactory recoveries ranging from 70.32% to 115.51% with 3.14%-13.56% intra-day relative standard deviations (RSD) and 4.92%-14.87% inter-day RSD.

Pan D; Wang J; Chen C; Huang C; Cai Q; Yao S

2013-04-01

64

Silica supported Fe3O 4 magnetic nanoparticles for magnetic solid-phase extraction and magnetic in-tube solid-phase microextraction: application to organophosphorous compounds.  

UK PubMed Central (United Kingdom)

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.

Moliner-Martinez Y; Vitta Y; Prima-Garcia H; González-Fuenzalida RA; Ribera A; Campíns-Falcó P; Coronado E

2013-10-01

65

Chemically modified alumina nanoparticles for selective solid phase extraction and preconcentration of trace amounts of Cd(II)  

International Nuclear Information System (INIS)

We have developed a solid phase extraction method for the determination of cadmium ions in aqueous samples. It is based on the adsorption of Cd(II) on alumina nanoparticles coated with sodium dodecyl sulfate and modified with a newly synthesized Schiff base. Analytical parameters such as pH value, amount of adsorbent, type and concentration of eluent, flow rates of the sample and eluent, sample volume and matrix effects were optimized. Desorption is accomplished with 2 mol L-1 nitric acid. Cd(II) was then determined by flame atomic absorption spectrometry. The maximum enrichment factor is 75. Under the optimum experimental conditions, the detection limit is 0.14 ?g L-1 in original solution. The adsorption capacity of the modified sorbent is 4.90 mg g-1 for cadmium ions. The method was applied to the determination of trace quantities of Cd(II) in water, wastewater, and biological and food samples with satisfactory results. (author)

2011-01-01

66

Quantitation of Binding, Recovery and Desalting Efficiency in Solid Phase Extraction Micropipette Tips  

Energy Technology Data Exchange (ETDEWEB)

Micropipette-tip solid phase extraction systems are common in proteomic analyses for desalting and concentrating samples for mass spectrometry, removing interferences, and increasing sensitivity. These systems are inexpensive, disposable, and highly efficient. Here we show micropipette-tip solid phase extraction is a direct sample preparation method for {sup 14}C-accelerator mass spectrometry (AMS), removing salts or reagent from labeled macromolecules. We compared loading, recovery and desalting efficiency in commercially available SPE micro-tips using {sup 14}C-labeled peptides and proteins, AMS, and alpha spectrometry ion energy loss quantitation. The polypropylene in the tips was nearly {sup 14}C-free and simultaneously provided low-background carrier for AMS. The silica material did not interfere with the analysis. Alpha spectrometry provided an absolute measurement of desalting efficiency.

Palmblad, M N; Vogel, J S

2004-08-02

67

Solid phase extraction of polyhalogenated pollutants from freshwater using chemically modified multi-walled carbon nanotubes and their determination by gas chromatography.  

UK PubMed Central (United Kingdom)

This paper describes the application of pristine and chemically modified multi-walled carbon nanotubes (MWCNTs) as packing materials for the preconcentration and determination of various polyhalogenated organic pollutants, pentachlorophenol, 2,4,5-trichlorophenol, 3,3',4,4'-tetrachlorobiphenyl, and 2,2',5,5'-tetrabromobiphenyl from real water samples based on solid-phase extraction. MWCNTs were chemically modified by octadecyl amine and polyethylene glycol, separately, and the resulting nano materials were used as packing materials for solid phase extraction. Method development, applicability, and suitability of the above mentioned adsorbents for the solid phase extraction were studied. Method development showed great reproducibility and sensitivity, and low limits of detection within a considerable linear range. The regeneration and reusability of the SPE cartridges were studied using Rideau River (Ottawa, Canada) surface water samples and the results showed that cartridges could be used for three cycles of adsorption/desorption with no loss of efficiency. In general, the results suggested that modification of MWCNTs affords a novel class of adsorbents, which could be used for the SPE of various analytes from aqueous solutions with great efficiency, recovery, reproducibility, sensitivity, and precision, within a wide range of analyte concentrations.

Abdel Salam M; Burk R

2009-04-01

68

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

International Nuclear Information System (INIS)

[en] 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

2012-03-01

69

Reducing the sulfur-dioxide binding power of sweet white wines by solid-phase extraction.  

UK PubMed Central (United Kingdom)

The high sulfur-dioxide binding power of sweet white wines may be reduced by extracting the naturally present carbonyl compounds from wine that are responsible for carbonyl bisulphites formation. The carbonyl compounds mainly responsible for trapping SO2 are acetaldehyde, pyruvic acid, and 2-oxoglutaric acid. The method employed was selective solid phase extraction, using phenylsulfonylhydrazine as a scavenging agent. The scavenging function was grafted onto a support prepared from raw materials derived from lignin. This approach is more acceptable to winemakers than the polymer media previously reported, as it reduces the possible contamination of wine to molecules already present in the wine making process.

Saidane D; Barbe JC; Birot M; Deleuze H

2013-11-01

70

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...

71

Rational design and chromatographic evaluation of histamine imprinted polymers optimised for solid-phase extraction of wine samples.  

UK PubMed Central (United Kingdom)

This article reports on the computational design, development and application of a molecularly imprinted polymer (MIP) with specific affinity towards histamine. Computational modelling was used to screen a monomer library in order to select the monomers able to form the strongest complex with the target analyte. These were subsequently used for MIP synthesis by radical polymerisation initiated by UV. MIPs were then evaluated by liquid chromatography and solid phase extraction (SPE) and best MIP behaviour was observed when itaconic acid was used as functional monomer. Finally, after optimisation of the polymer composition, MIPs were used as adsorbents for SPE and clean-up of histamine in wine samples. The proposed histamine extraction method with the MIP-SPE cartridge was found to be reproducible (<5% RSD) and accurate (93-99% recovery) and provided clear wine extracts. The described methodology is simple and fast and is suitable for the selective histamine extraction and its subsequent quantification by HPLC-DAD from complex matrices such as wine samples.

Basozabal I; Gomez-Caballero A; Diaz-Diaz G; Guerreiro A; Gilby S; Goicolea MA; Barrio RJ

2013-09-01

72

Molecularly Imprinted Solid-Phase Extraction for Selective Trace Analysis of Trifluoperazine.  

UK PubMed Central (United Kingdom)

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.

Attaran AM; Mohammadi N; Javanbakht M; Akbari-Adergani B

2013-06-01

73

Development of a solid phase extraction method for agricultural pesticides in large-volume water samples.  

UK PubMed Central (United Kingdom)

An analytical method using solid phase extraction (SPE) and analysis by gas chromatography/mass spectrometry (GC-MS) was developed to determine trace levels of a variety of 41 agricultural pesticides and selected transformation products in high-elevation surface waters. Large-volume water sampling (up to 100L) was employed because it was anticipated that pesticide contamination, if present, would be at very low levels. The target compounds comprise pesticides (and selected oxygen transformation products) known to have been extensively used in agriculture in the San Joaquin Valley, CA, USA. Solid phase extraction using the polymeric resin Abselut Nexus was optimized to extract the pesticide analytes from water samples. A single determinative method using GC-MS with electron ionization was used for all the analytes. Recoveries from 100L of reagent water at 100pg/L and 1ng/L concentrations were generally greater than 75%, although dimethoate, disulfoton, and phorate were not recovered. Analysis of the extracts without cleanup yielded detection limits for the remaining 38 analytes between 0.1 and 30ng/L. A silica cleanup with separate analysis of 3 eluant fractions improved detection limits for 37 of the compounds to between 6 and 600pg/L in high-elevation surface waters.

Momplaisir GM; Rosal CG; Heithmar EM; Varner KE; Riddick LA; Bradford DF; Tallent-Halsell NG

2010-06-01

74

New Ionic Liquid Modified Polymeric Microspheres for Solid-Phase Extraction of Four Sudan Dyes in Foodstuff Samples.  

UK PubMed Central (United Kingdom)

The new ionic liquid modified polymeric microspheres (ILPM) were synthesized by precipitation polymerization using 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF(6)]) as the functional monomer, divinylbenzene (DVB) as the cross-linker, and a mixture of toluene and acetonitrile as the dispersant solvent. The obtained ILPM showed good adsorbability to the four kinds of Sudan dyes and were successfully applied as a special sorbent of solid-phase extraction (SPE) coupled with high-performance liquid chromatography (HPLC) for the simultaneous isolation and determination of four Sudan dyes from foodstuff samples. Compared with the traditional SPE adsorbents such as neutral alumina and C(18), the ILPM sorbents provided higher recovery with a significant purification effect. Good linearity was obtained in a range of 0.05-4.0 ?g/g (r(2) ? 0.9996) for the four kinds of Sudan dyes, and the average recoveries at three spiked levels ranged from 92.5% to 106.1% with the relative standard deviations ?5.7%. The proposed ILPM-SPE-HPLC method could be potentially applied to rapid isolation and determination of Sudan dyes in complicated food samples.

Yan H; Gao M; Qiao J

2012-06-01

75

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.

Dandan Han; Kyung Ho Row

2011-01-01

76

Solid phase extraction: Applications to the chromatographic analysis of vegetable oils and fats  

Directory of Open Access Journals (Sweden)

Full Text Available Applications of solid-phase extraction for the isolation of certain lipid classes prior to chromatographic analysis are given. More information was found for sterols and related compounds, polar phenols and contaminants such as polycyclic aromatic hydrocarbons. Detailed analytical protocols are presented and discussed in many cases.Se analizan las aplicaciones de la extracción en fase sólida para el aislamiento de ciertos lípidos previamente al análisis cromatográfico. La mayor parte de la información se refiere a los esteroles y compuestos relacionados, fenoles polares y contaminantes como los hidrocarburos aromáticos policíclicos. Se muestran y discuten numerosos protocolos analíticos en detalle.

Panagiotopoulou, P. M.; Tsimidou, M.

2002-01-01

77

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)

2005-01-01

78

Tandem solid-phase extraction of atrazine ozonation products in water.  

UK PubMed Central (United Kingdom)

The preconcentration of aqueous solutions containing atrazine degradation products was investigated using solid-phase extraction on octadecyl and cation-exchanger silica phases. The retention and elution steps were studied and evaluated separately in order to define and optimize the critical experimental parameters involved. A strategy which combines sequentially both phases is proposed to fractionate compounds into two groups of increasing polarities: firstly, the native pesticide, hydroxyatrazine and most chlorotriazines on octadecyl support, and secondly monodealkylated hydroxytriazines, ammeline and ammelide on cation-exchanger. This tandem procedure was successfully applied for analysing and quantifying atrazine ozonation products and its efficiency demonstrated using [U-ring 14C]-labelled atrazine experiments.

Nélieu S; Stobiecki M; Einhorn J

2000-01-01

79

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

2011-03-12

80

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

UK PubMed Central (United Kingdom)

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.

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

2011-06-01

 
 
 
 
81

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

Science.gov (United States)

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.

Gutiérrez-Solís, M. C.; Muñoz-Rodríguez, D.; Medina-Peralta, S.; Carrera-Figueiras, C.; Ávila-Ortega, A.

2013-06-01

82

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

83

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

UK PubMed Central (United Kingdom)

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 644nm. Beer's law was obeyed up to 450ngmL(-1) of iron. The molar absorptivity, Sandell's sensitivity, detection and quantification limits were calculated and found to be 1.09×10(5)Lmol(-1)cm(-1), 0.51ngcm(-2), 1.98 and 6.0ngmL(-1), respectively and compared with parameters obtained without using solid phase extraction method. After reduction of Fe(III) by addition of 2.0mL 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%).

Kassem MA; Amin AS

2013-12-01

84

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 644nm. Beer's law was obeyed up to 450ngmL(-1) of iron. The molar absorptivity, Sandell's sensitivity, detection and quantification limits were calculated and found to be 1.09×10(5)Lmol(-1)cm(-1), 0.51ngcm(-2), 1.98 and 6.0ngmL(-1), respectively and compared with parameters obtained without using solid phase extraction method. After reduction of Fe(III) by addition of 2.0mL 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

2013-05-20

85

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

Science.gov (United States)

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, (19)F 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 100mL 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 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. PMID:23107136

Yan, Xiao Qing; Shen, Qian Jin; Zhao, Xiao Ran; Gao, Hai Yue; Pang, Xue; Jin, Wei Jun

2012-09-26

86

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

UK PubMed Central (United Kingdom)

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, (19)F 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 100mL 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 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.

Yan XQ; Shen QJ; Zhao XR; Gao HY; Pang X; Jin WJ

2012-11-01

87

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

Energy Technology Data Exchange (ETDEWEB)

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{sup -1}. The relative standard deviations (R.S.D.) at a concentration level of 0.1 ng mL{sup -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{sup -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.

Bagheri, Habib [Department of Chemistry, Sharif University of Technology, Azadi Av., P.O. Box 11365-9516, Tehran (Iran, Islamic Republic of)], E-mail: bagheri@sharif.edu; Babanezhad, Esmaeil; Khalilian, Faezeh [Department of Chemistry, Sharif University of Technology, Azadi Av., P.O. Box 11365-9516, Tehran (Iran, Islamic Republic of)

2009-02-23

88

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 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

1136-01-00

89

Matrix solid-phase dispersion extraction for chromatographic analysis of labdane diterpenoids in Coleus forskohlii.  

UK PubMed Central (United Kingdom)

INTRODUCTION: The quality of Coleus forskohlii is often evaluated by high performance liquid chromatography (HPLC), using bioactive labdane diterpenoids as chemical markers. However, the existing sample preparation methods for the analysis of diterpenoids in C. forskohlii are generally labour-intensive, time-consuming and require large volumes of solvents. OBJECTIVE: To establish an efficient matrix solid-phase dispersion (MSPD) extraction method for the simultaneous analysis of five bioactive diterpenoids in C. forskohlii by HPLC. METHODOLOGY: Herbal samples were prepared by an optimised MSPD procedure using C(18) as the sorbent. The quantification of the diterpenoids was achieved by HPLC with evaporative light scattering detector (ELSD), and the identification of the five compounds was performed by HPLC with tandem mass detector (MS/MS). The efficiency of the MSPD method was also compared with other extraction techniques including Soxhlet extraction, heat reflux extraction, ultrasonic-assisted extraction and microwave-assisted extraction. RESULTS: The MSPD extracted five diterpenoids with satisfactory recoveries ranging from 98.36% to 102.08%. Compared with other extraction methods, the proposed MSPD method had the advantages of combining extraction and clean-up into a single step, consuming less time and requiring lower solvent volumes. CONCLUSION: The MSPD method is simple, rapid and efficient for the extraction of labdane diterpenoids from C. forskohlii. The MSPD procedure coupled with HPLC-ELSD or HPLC-MS/MS is suitable for the quantification and identification of the diterpenoids in C. forskohlii.

Yin J; Wang Y; Tan B; Kang Y; Xie D; Tian L; Huang J

2013-02-01

90

Application of sulfur microparticles for solid-phase extraction of polycyclic aromatic hydrocarbons from sea water and wastewater samples.  

UK PubMed Central (United Kingdom)

The application of sulfur microparticles as efficient adsorbents for the solid-phase extraction (SPE) and determination of trace amounts of 10 polycyclic aromatic hydrocarbons (PAHs) was investigated in sea water and wastewater samples using high performance liquid chromatography coupled with an ultraviolet detector (HPLC-UV). Parameters influencing the preconcentration of PAHs such as the amount of sulfur, solution flow rate and volume, elution solvent, type and concentration of organic modifier, and salt effect were examined. The results showed that at a flow rate of 10 mL min(-1) for the sample solutions (100mL), the PAHs could be adsorbed on the sulfur microparticles and then eluted by 2.0 mL of acetonitrile. For HPLC-UV analysis of extracted PAHs, the calibration curves were linear in the range of 0.05-80.0 ?g L(-1); the coefficients of determinations (r(2)) were between 0.9934 and 0.9995. The relative standard deviations (RSDs) for eight replicates at two concentration levels (0.5 and 4.0 ?g L(-1)) of PAHs were lower than 7.3%, under optimized conditions. The limits of detection (LODs, S/N = 3) of the proposed method for the studied PAHs were 0.007-0.048 ?g L(-1). The recoveries of spiked PAHs (0.5 and 4 ?g L(-1)) in the wastewater and sea water samples ranged from 78% to 108%. The simplicity of experimental procedure, high extraction efficiency, short sample analysis, and using of low cost sorbent demonstrate the potential of this approach for routine trace PAH analysis in water and wastewater samples.

Khalili-Fard V; Ghanemi K; Nikpour Y; Fallah-Mehrjardi M

2012-02-01

91

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

International Nuclear Information System (INIS)

[en] 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)

2011-01-01

92

Solid phase extraction of petroleum carboxylic acids using a functionalized alumina as stationary phase.  

UK PubMed Central (United Kingdom)

Petroleum essentially consists of a mixture of organic compounds, mainly containing carbon and hydrogen, and, in minor quantities, compounds with nitrogen, sulphur, and oxygen. Some of these compounds, such as naphthenic acids, can cause corrosion in pipes and equipment used in processing plants. Considering that the methods of separation or clean up the target compounds in low concentrations and in complex matrix use large amounts of solvents or stationary phases, is necessary to study new methodologies that consume smaller amounts of solvent and stationary phases to identify the acid components present in complex matrix, such as crude oil samples. The proposed study aimed to recover acid compounds using the solid phase extraction method, employing different types of commercial stationary ion exchange phases (SAX and NH(2)) and new phase alumina functionalized with 1,4-bis(n-propyl)diazoniabicyclo[2.2.2]octane chloride silsesquioxane (Dab-Al(2)O(3)), synthesized in this work. Carboxylic acids were used as standard mixture in the solid phase extraction for further calculation of recovery yield. Then, the real sample (petroleum) was fractionated into saturates, aromatics, resins, and asphaltenes, and the resin fraction of petroleum (B1) was eluted through stationary ion exchange phases. The stationary phase synthesized in this work showed an efficiency of ion exchange comparable to that of the commercial stationary phases.

de Conto JF; Nascimento Jdos S; de Souza DM; da Costa LP; Egues SM; Freitas Ldos S; Benvenutti EV

2012-04-01

93

Rapid solid-phase extraction and analysis of resveratrol and other polyphenols in red wine.  

Science.gov (United States)

Red wine has long been credited as a good source of health-beneficial antioxidants, including the bioactive polyphenols catechin, quercetin, and (E)-resveratrol. In this paper, we report the application of reusable molecularly imprinted polymers (MIPs) for the selective and robust solid-phase extraction (SPE) and rapid analysis of (E)-resveratrol (LOD=8.87×10(-3)mg/L, LOQ=2.94×10(-2)mg/L), along with a range of other polyphenols from an Australian Pinot noir red wine. Optimization of the molecularly imprinted solid-phase extraction (MISPE) protocol resulted in the significant enrichment of (E)-resveratrol and several structurally related polyphenols. These secondary metabolites were subsequently identified by RP-HPLC and ?LC-ESI ion trap MS/MS methods. The developed MISPE protocol employed low volumes of environmentally benign solvents selected according to the Green Chemistry principles, and resulted in the recovery of 99% of the total (E)-resveratrol present. These results further demonstrate the potential of generic protocols for the analysis of target compound with health beneficial properties within the food and nutraceutical industries using tailor-made MIPs. PMID:23871560

Hashim, Shima N N S; Schwarz, Lachlan J; Boysen, Reinhard I; Yang, Yuanzhong; Danylec, Basil; Hearn, Milton T W

2013-06-28

94

Rapid solid-phase extraction and analysis of resveratrol and other polyphenols in red wine.  

UK PubMed Central (United Kingdom)

Red wine has long been credited as a good source of health-beneficial antioxidants, including the bioactive polyphenols catechin, quercetin, and (E)-resveratrol. In this paper, we report the application of reusable molecularly imprinted polymers (MIPs) for the selective and robust solid-phase extraction (SPE) and rapid analysis of (E)-resveratrol (LOD=8.87×10(-3)mg/L, LOQ=2.94×10(-2)mg/L), along with a range of other polyphenols from an Australian Pinot noir red wine. Optimization of the molecularly imprinted solid-phase extraction (MISPE) protocol resulted in the significant enrichment of (E)-resveratrol and several structurally related polyphenols. These secondary metabolites were subsequently identified by RP-HPLC and ?LC-ESI ion trap MS/MS methods. The developed MISPE protocol employed low volumes of environmentally benign solvents selected according to the Green Chemistry principles, and resulted in the recovery of 99% of the total (E)-resveratrol present. These results further demonstrate the potential of generic protocols for the analysis of target compound with health beneficial properties within the food and nutraceutical industries using tailor-made MIPs.

Hashim SN; Schwarz LJ; Boysen RI; Yang Y; Danylec B; Hearn MT

2013-06-01

95

Immobilized humic substances and immobilized aggregates of humic substances as sorbent for solid phase extraction.  

Science.gov (United States)

In this work, humic substances (HS) immobilized, as a thin layer or as aggregates, on silica gel were tested as material for solid phase extraction. Some triazines (simazine, atrazine, therbutylazine, atrazine-desethyl-desisopropyl-2-hydroxy, ametryn and terbutryn), have been selected as test analytes due to their environmental importance and to span a large range of solubility and octanol/water partition coefficient (logP). The sorbent was obtained immobilizing a thin layer of HS via physisorption on a pre-coated silica gel with a cationic polymer (polybrene). While the sorbent could be used as it is, it was demonstrated that additional HS could be immobilized, via weak interactions, to form stable humic aggregates. However, while a higher quantity of HS could be immobilized, no significant differences were observed in the sorption parameters. This sorbent have been tested for solid phase extraction to concentrate triazines from aqueous matrixes. The sorbent demonstrated performances equivalent to commercial alternatives as a concentration factor between 50 and 200, depending on the type of triazines, was obtained. Moreover the low cost and the high flow rate of sample through the column allowed using high quantity of sorbent. The analytical procedure was tested with different matrixes including tap water, river water and estuarine water. PMID:23916952

Erny, Guillaume L; Gonçalves, Bruna M; Esteves, Valdemar I

2013-07-19

96

Immobilized humic substances and immobilized aggregates of humic substances as sorbent for solid phase extraction.  

UK PubMed Central (United Kingdom)

In this work, humic substances (HS) immobilized, as a thin layer or as aggregates, on silica gel were tested as material for solid phase extraction. Some triazines (simazine, atrazine, therbutylazine, atrazine-desethyl-desisopropyl-2-hydroxy, ametryn and terbutryn), have been selected as test analytes due to their environmental importance and to span a large range of solubility and octanol/water partition coefficient (logP). The sorbent was obtained immobilizing a thin layer of HS via physisorption on a pre-coated silica gel with a cationic polymer (polybrene). While the sorbent could be used as it is, it was demonstrated that additional HS could be immobilized, via weak interactions, to form stable humic aggregates. However, while a higher quantity of HS could be immobilized, no significant differences were observed in the sorption parameters. This sorbent have been tested for solid phase extraction to concentrate triazines from aqueous matrixes. The sorbent demonstrated performances equivalent to commercial alternatives as a concentration factor between 50 and 200, depending on the type of triazines, was obtained. Moreover the low cost and the high flow rate of sample through the column allowed using high quantity of sorbent. The analytical procedure was tested with different matrixes including tap water, river water and estuarine water.

Erny GL; Gonçalves BM; Esteves VI

2013-09-01

97

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; QIUFEN HU; ZHANGJIE HUANG; JIAYUAN YIN; GANG XIE; JING CHEN

2006-01-01

98

Solid phase extraction and determination of PAHs in soil- and oilsamples. Festphasenextraktion und Bestimmung von PAKs aus Boden- und Oelproben  

Energy Technology Data Exchange (ETDEWEB)

A simple, rapid and economized method was developed for PAH determination in soil and oil samples. The PAHs in the crude extracts first were separated from contaminations by solid-phase extraction and then determined by HPLC with UV- or fluorescence detection. HPLC in combination with fluorescence detection is a selective and sensitive method. For each compound the detection limit is in the range of 3 to 30 pg. The advantages of this method using solid-phase extraction and HPLC separation technique in comparison to liquid/liquid extraction or GC results in economical working. (orig.).

Kicinski, H.G.; Adamek, S.; Kettrup, A. (Paderborn Univ. (Gesamthochschule) (Germany, F.R.). Fachgebiet Angewandte Chemie)

1989-12-01

99

Molecularly imprinted polymer for solid-phase extraction of rutin in complicated traditional Chinese medicines.  

UK PubMed Central (United Kingdom)

In the present work, an improved and direct approach for the preparation of molecularly imprinted polymers (MIPs) was proposed. The MIPs were prepared based on bulk polymerization by water-bath heating and ultrasonic elution of the template, using rutin as the template, acrylamide (AM) as the functional monomer and 2,2'-azobisisobutyronitrile (AIBN) as the cross linker. Molecularly imprinted polymers prepared by other elution methods, including microwave-assisted extraction and conventional Soxhlet extraction, were used for comparison and the results showed that the ultrasonic elution method is the best. The synthesized MIPs were characterized by Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). High performance liquid chromatography (HPLC) was used to evaluate the adsorption properties and recognition mechanism of the MIPs. Structurally similar compounds including quercetin and genistein were utilized for verifying the molecular selectivity and characterizing the recognition capability of the MIPs. The MIPs were used as a sorbent for the solid phase extraction of rutin, and the resultant cartridge showed a good extraction performance. Thus, a molecularly imprinted solid-phase extraction (MISPE) procedure for selective pre-concentration of rutin from complicated traditional Chinese medicine (TCM) samples was proposed. Various elution parameters that affect the adsorption capacity of the polymer were evaluated to optimize the selective pre-concentration of rutin. The characteristics of the MISPE method were validated by HPLC. The recoveries ranged from 85% to 91% for TCMs, which demonstrated that this MISPE-HPLC method could be applied to pre-concentrate and determinate rutin directly from complicated TCM samples in the presence of other interfering substances.

Peng L; Wang Y; Zeng H; Yuan Y

2011-02-01

100

Molecularly imprinted polymer for solid-phase extraction of rutin in complicated traditional Chinese medicines.  

Science.gov (United States)

In the present work, an improved and direct approach for the preparation of molecularly imprinted polymers (MIPs) was proposed. The MIPs were prepared based on bulk polymerization by water-bath heating and ultrasonic elution of the template, using rutin as the template, acrylamide (AM) as the functional monomer and 2,2'-azobisisobutyronitrile (AIBN) as the cross linker. Molecularly imprinted polymers prepared by other elution methods, including microwave-assisted extraction and conventional Soxhlet extraction, were used for comparison and the results showed that the ultrasonic elution method is the best. The synthesized MIPs were characterized by Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). High performance liquid chromatography (HPLC) was used to evaluate the adsorption properties and recognition mechanism of the MIPs. Structurally similar compounds including quercetin and genistein were utilized for verifying the molecular selectivity and characterizing the recognition capability of the MIPs. The MIPs were used as a sorbent for the solid phase extraction of rutin, and the resultant cartridge showed a good extraction performance. Thus, a molecularly imprinted solid-phase extraction (MISPE) procedure for selective pre-concentration of rutin from complicated traditional Chinese medicine (TCM) samples was proposed. Various elution parameters that affect the adsorption capacity of the polymer were evaluated to optimize the selective pre-concentration of rutin. The characteristics of the MISPE method were validated by HPLC. The recoveries ranged from 85% to 91% for TCMs, which demonstrated that this MISPE-HPLC method could be applied to pre-concentrate and determinate rutin directly from complicated TCM samples in the presence of other interfering substances. PMID:21152622

Peng, Lin; Wang, Yuzhi; Zeng, Huan; Yuan, Ya

2010-12-13

 
 
 
 
101

Molecularly imprinted solid-phase extraction for the determination of fenitrothion in tomatoes.  

UK PubMed Central (United Kingdom)

Organophosphorus insecticides are widely employed in agriculture, and residues of them can remain after harvesting or storage. Pesticide residue control is an important task for ensuring food safety. Common chromatographic methods used in the determination of pesticide residues in food require clean-up and concentration steps prior to quantitation. While solid-phase extraction has been widely employed for this purpose, there is a need to improve selectivity. Due to their inherent biomimetic recognition systems, molecularly imprinted polymers (MIP) allow selectivity to be enhanced while keeping the costs of analysis low. In this work, a MIP that was designed to enable the selective extraction of fenitrothion (FNT) from tomatoes was synthesized using a noncovalent imprinting approach. The polymer was prepared using methacrylic acid as functional monomer and ethyleneglycol dimethacrylate as crosslinking monomer in dichloromethane (a porogenic solvent). The polymer was characterized by Fourier transform infrared spectroscopy, solid-state nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), and nitrogen sorption porosimetry. The pore structure and the surface area were evaluated using the BET adsorption method. To characterize the batch rebinding behavior of the MIP, the adsorption isotherm was measured, allowing the total number of binding sites, the average binding affinity and the heterogeneity index to be established. A voltammetric method of quantifying FNT during the molecularly imprinted solid-phase extraction (MISPE) studies was developed. The polymer was placed in extraction cartridges which were then used to clean up and concentrate FNT in tomato samples prior to high-performance liquid chromatographic quantitation. The material presented a medium extraction efficiency of 59% (for analyses performed with three different cartridges on three days and a fortification level of 5.0 microg g(-1)) and selectivity when used in the preparation of tomato samples, and presented the advantage that the polymer could be reused several times after regeneration.

Pereira LA; Rath S

2009-02-01

102

Determination of chloroethenes in environmental biological samples using gas chromatography coupled with solid phase micro extraction  

Energy Technology Data Exchange (ETDEWEB)

An analytical method has been developed to determine the chloroethene series, tetrachloroethene (PCE), trichloroethene (TCE), cisdichloroethene (cis-DCE) and transdichloroethene (trans-DCE) in environmental biotreatment studies using gas chromatography coupled with a solid phase micro extraction (SPME) technique. The volatile chlorinated compounds in aqueous solution can be analyzed directly without solvent extraction, purge and trap, or thermal heating. The calibration curves have demonstrated good linear relationships within 50.0 to 300.0 {mu}g L{sup -1} concentration range. Detection limits are 18.0, 5.0, 25.0, and 42.0 {mu}g L{sup -1}, for PCE, TCE, cis-DCE and trans-DCE, respectively. Factors which affect the SPME process, such as sample adsorption time, thermal desorption time, and concentration of salt in the matrix, have also been evaluated. (orig.)

Xu, N. [United States Environmental Protection Agency, National Risk Management Research Lab., Ada, OK (United States); Vandegrift, S. [ManTech Environmental Research Services Corp., Ada, OK (United States); Sewell, G.W. [United States Environmental Protection Agency, National Risk Management Research Lab., Ada, OK (United States)

1996-03-01

103

Extraction of pesticides from plants using solid phase microextraction and QuEChERS  

Scientific Electronic Library Online (English)

Full Text Available 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 aldrin, 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 (more) 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.

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

2013-08-01

104

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; Martine Perrin

2008-01-01

105

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

UK PubMed Central (United Kingdom)

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.

Ibarra IS; Rodriguez JA; Páez-Hernández ME; Santos EM; Miranda JM

2012-07-01

106

Combination of graphene oxide-based solid phase extraction and electro membrane extraction for the preconcentration of chlorophenoxy acid herbicides in environmental samples.  

UK PubMed Central (United Kingdom)

Combination of different extraction methods is an interesting and debatable work in the field of sample preparation. In the current study, for the first time, solid phase extraction combined with electro membrane extraction (SPE-EME) was developed for ultra-preconcentration and determination of chlorophenoxy acid herbicides in environmental samples using capillary electrophoresis (CE). In the mentioned method, first, a 100mL of chlorophenoxy acid herbicides (2-methyl-4-chlorophenoxyacetic acid (MCPA), 2-(2,4-dichlorophenoxy) propanoic acid (2,4-DP) and 2-(4-chloro-2-methylphenoxy) propanoic acid (MCPP)) was passed through a column of graphene oxide as a solid phase, and then the adsorbed herbicides were eluted by 4.0mL of 8% acetic acid (HOAC) in methanol. Then, the elution solvent was evaporated and the herbicides residue was dissolved in 4.0mL of double distilled water (pH 9.0). Afterwards, the herbicides in 4.0mL of the aqueous solution were transferred to an EME glass vial. In the EME step, the herbicides were extracted from the sample solution into the basic acceptor solution (pH 13.0) under electrical potential, which was held inside the lumen of the fiber with 1-octanol as the supported liquid membrane (SLM). Under the optimized conditions, high enrichment factors were obtained in the range of 1950-2000. The limits of quantification (LOQs) and method detection limits (MDLs) were obtained in the range of 1.0-1.5 and 0.3-0.5ngmL(-1), respectively. Finally, the performance of the present method was evaluated for extraction and determination of chlorophenoxy acid herbicides in environmental samples.

Tabani H; Fakhari AR; Shahsavani A; Behbahani M; Salarian M; Bagheri A; Nojavan S

2013-07-01

107

Combination of graphene oxide-based solid phase extraction and electro membrane extraction for the preconcentration of chlorophenoxy acid herbicides in environmental samples.  

Science.gov (United States)

Combination of different extraction methods is an interesting and debatable work in the field of sample preparation. In the current study, for the first time, solid phase extraction combined with electro membrane extraction (SPE-EME) was developed for ultra-preconcentration and determination of chlorophenoxy acid herbicides in environmental samples using capillary electrophoresis (CE). In the mentioned method, first, a 100mL of chlorophenoxy acid herbicides (2-methyl-4-chlorophenoxyacetic acid (MCPA), 2-(2,4-dichlorophenoxy) propanoic acid (2,4-DP) and 2-(4-chloro-2-methylphenoxy) propanoic acid (MCPP)) was passed through a column of graphene oxide as a solid phase, and then the adsorbed herbicides were eluted by 4.0mL of 8% acetic acid (HOAC) in methanol. Then, the elution solvent was evaporated and the herbicides residue was dissolved in 4.0mL of double distilled water (pH 9.0). Afterwards, the herbicides in 4.0mL of the aqueous solution were transferred to an EME glass vial. In the EME step, the herbicides were extracted from the sample solution into the basic acceptor solution (pH 13.0) under electrical potential, which was held inside the lumen of the fiber with 1-octanol as the supported liquid membrane (SLM). Under the optimized conditions, high enrichment factors were obtained in the range of 1950-2000. The limits of quantification (LOQs) and method detection limits (MDLs) were obtained in the range of 1.0-1.5 and 0.3-0.5ngmL(-1), respectively. Finally, the performance of the present method was evaluated for extraction and determination of chlorophenoxy acid herbicides in environmental samples. PMID:23688683

Tabani, Hadi; Fakhari, Ali Reza; Shahsavani, Abolfath; Behbahani, Mohammad; Salarian, Mani; Bagheri, Akbar; Nojavan, Saeed

2013-04-17

108

On-line solid-phase extraction coupled to supercritical fluid chromatography to determine phenol and nitrophenols in water.  

UK PubMed Central (United Kingdom)

Determining of phenol and nitrophenols using solid-phase extraction on-line coupled to supercritical fluid chromatography (SFC) is studied. SFC quickly separated the compounds studied, in less than 6 min, and solid-phase extraction was used to decrease the limits of detection. C18, PLRP-S and a highly cross-linked styrene-divinylbenzene copolymer in a 10 x 3 mm I.D. laboratory-packed precolumn were tested comparatively as sorbents in the preconcentration step. Tetrabutylammonium bromide was used as ion-pair reagent in the extraction process to increase breakthrough volumes, mainly for phenol. Performance of the method was checked with tap and river waters.

Pocurull E; Marcé RM; Borrull F; Bernal JL; Toribio L; Serna ML

1996-11-01

109

Headspace Solid Phase Microextraction in Pesticide Residues Analysis:1. Optimisation of Extraction Conditions  

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Full Text Available The method of headspace solid phase microextraction (HS/SPME) was successfully used in a simultaneous multicomponent analysis of hexachlorobenzene (HCB), tefluthrin, heptachlor, aldrin, chlorpyrifos, fenthion and bifenthrin in aqueous medium. Measurementswere performed using a nonpolar polydimethyl siloxane (PDMS) fiber. Detection and quantification were done by gas chromatography/mass spectrometry (GC/MS).Optimal conditions for HS/SPME were determined both by performing extraction at different temperatures and examining extraction time profiles at constant temperature. Optimal extraction temperature for each pesticide studied was determined as follows: 60°C for HCB and for heptachlor, 80°C for aldrin and for chlorpyrifos, fenthion and tefluthrin, and temperature exceeding 80°C for bifenthrin. For the pesticide mixture studied, 60°C was identified as the optimum extraction temperature.Based on the time profiles obtained, it was confirmed that satisfactory extraction sensitivity can be obtained even for extraction times shorter than the time required to reach a sorption equilibrium. This conclusion was confirmed by linear concentration profiles obtained for the following ranges: 0.05-10 ng/ml (HCB), 0.05-25 ng/ml (tefluthrin), 0.05-40 ng/ml (heptachlor), 0.05-40 ng/ml (aldrin), 0.05-25 ng/ml (chlorpyrifos), 0.05-25 ng/ml (fenthion)and 0.05-25 ng/ml (bifenthrin).Relative standard deviation (RSD) values for triplicate measurements did not exceed 15%.

Rada ?urovi?; Jelena Milinovi?; Mirjana Markovi?; Dragan Markovi?

2007-01-01

110

Determination of additives in cosmetics by supercritical fluid extraction on-line headspace solid-phase microextraction combined with gas chromatography-mass spectrometry.  

UK PubMed Central (United Kingdom)

A new hyphenated technique couples supercritical fluid extraction in situ derivatization and on-line headspace solid-phase microextraction to gas chromatography-mass spectrometry (SFE in situ derivatization on-line HS-SPME-GC-MS) for the determination of paraben preservatives and polyphenolic antioxidants in cosmetics. The preservatives and antioxidants were extracted from the cosmetic matrices with supercritical carbon dioxide at a pressure of 13,840 kPa. The supercritical fluid extraction was performed at 55 degrees C for 10 min of static extraction then 15 min of dynamic extraction. The extractant subsequently was derivatized in situ with the silylation reagent N,O-bis(trimethylsilyl)trifluoroacetamide with 0.1% trimethylchlorosilane. The product was then adsorbed on a polyacrylate solid-phase microextraction (SPME) fiber in the headspace. Sea sand was used as a dispersive material in the SFE step. The analytical linear ranges for the preservatives and antioxidants were found to be from 10 to 1000 ng g(-1) with RSD values below 7.8%. The detection limits ranged from 0.5 to 8.3 ng g(-1). These results are better than those obtained by using only SPME or SFE for trace preservatives and antioxidants analysis in cosmetic matrices. The new method was successfully utilized to determine the amounts of preservatives and antioxidants in real cosmetics without the need for tedious pretreatments.

Yang TJ; Tsai FJ; Chen CY; Yang TC; Lee MR

2010-06-01

111

Determination of additives in cosmetics by supercritical fluid extraction on-line headspace solid-phase microextraction combined with gas chromatography-mass spectrometry.  

Science.gov (United States)

A new hyphenated technique couples supercritical fluid extraction in situ derivatization and on-line headspace solid-phase microextraction to gas chromatography-mass spectrometry (SFE in situ derivatization on-line HS-SPME-GC-MS) for the determination of paraben preservatives and polyphenolic antioxidants in cosmetics. The preservatives and antioxidants were extracted from the cosmetic matrices with supercritical carbon dioxide at a pressure of 13,840 kPa. The supercritical fluid extraction was performed at 55 degrees C for 10 min of static extraction then 15 min of dynamic extraction. The extractant subsequently was derivatized in situ with the silylation reagent N,O-bis(trimethylsilyl)trifluoroacetamide with 0.1% trimethylchlorosilane. The product was then adsorbed on a polyacrylate solid-phase microextraction (SPME) fiber in the headspace. Sea sand was used as a dispersive material in the SFE step. The analytical linear ranges for the preservatives and antioxidants were found to be from 10 to 1000 ng g(-1) with RSD values below 7.8%. The detection limits ranged from 0.5 to 8.3 ng g(-1). These results are better than those obtained by using only SPME or SFE for trace preservatives and antioxidants analysis in cosmetic matrices. The new method was successfully utilized to determine the amounts of preservatives and antioxidants in real cosmetics without the need for tedious pretreatments. PMID:20493297

Yang, Tzung-Jie; Tsai, Feng-Jie; Chen, Chung-Yu; Yang, Thomas Ching-Cherng; Lee, Maw-Rong

2010-04-18

112

Liquid chromatographic determination of amoxicillin concentrations in bovine plasma by using a tandem solid-phase extraction method.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We report a means of determining amoxicillin in bovine plasma by liquid chromatography with UV detection at 235 nm. Purification and concentration of extracts were accomplished by a tandem solid-phase extraction procedure with two reversed-phase columns. Separation of amoxicillin from interferences ...

Nelis, H J; Vandenbranden, J; De Kruif, A; De Leenheer, A P

113

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)

2007-01-01

114

Column solid?phase extraction of sunset yellow and spectrophotometric determination of its use in powdered beverage and confectionery products  

UK PubMed Central (United Kingdom)

A new and simple solid?phase extraction method for the determination of trace levels of sunset yellow has been developed on Diaion HP 2MG column system. The adsorbed sunset yellow on the resin was eluted with 3?mL of methanol and determined by UV–Vis spectrophotometry at 484?nm. Various experimental parameters such as pH, amount of sunset yellow, flow rates of sample and eluent solutions, resin amount, sample volumes, etc. were investigated. The influences of some alkali, alkali earth and transition metals on the recoveries of sunset yellow were investigated. The recovery values for sunset yellow were higher than 95%. Preconcentration factor was found as 150. The detection limit (three sigma) of the reagent blank for sunset yellow was 5.2??g?L?1. The relative standard deviations (RSD) of the procedure were found as 3.9%. The validation of the presented procedure was performed by the method of standard addition. The procedure was successfully applied to the determination of trace levels of sunset yellow in powdered beverage and confectionery products.

Unsal YE; Soylak M; Tuzen M

2012-06-01

115

Speciation of chromium in mineral waters and salinas by solid-phase extraction and graphite furnace atomic absorption spectrometry.  

Science.gov (United States)

A simple GF-AAS method for speciation analysis of chromium in mineral waters and salinas was developed. Cr(VI) species were separated from Cr(III) by solid-phase extraction with APDC (ammonium pyrrolidinedithiocarbamate). The APDC complexes were formed in the sample solution under proper conditions, adsorbed on Diaion HP-2MG resin and the resin was separated from the sample. After elution with concentrated nitric acid Cr(VI) was determined by GF-AAS. Total chromium was determined by GF-AAS directly in the sample and Cr(III) concentration was calculated as the difference between those results. The detection limit of the method defined as 3s of background variation was 0.03mugl(-1) for Cr(VI) and 0.3mugl(-1) for total chromium. RSD for Cr(VI) determination at the concentration of 0.14mugl(-1) was 9%, and for total chromium at the concentration of 5.6mugl(-1) was 5%. The recovery of Cr(VI) was in the range of 94-100%, dependently on type of the sample. The investigation of recovery of the spiked Cr(VI) showed that at concentration levels near 1mugl(-1) and lower recovery may be reduced significantly even by pure reagents that seem to be free from any reductants. PMID:18970128

Chwastowska, Jadwiga; Skwara, Witold; Sterli?ska, Elzbieta; Pszonicki, Leon

2005-02-26

116

Solid phase extraction of iron and lead in environmental matrices on amberlite xad-1180/pv  

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Full Text Available A solid phase extraction procedure using Amberlite XAD-1180/Pyrocatechol violet (PV) chelating resin for the determination of iron and lead ions in various environmental samples was established. The procedure is based on the sorption of lead(II) and iron(III) ions onto the resin at pH 9, followed by elution with 1 mol/L HNO3 and determination by flame atomic absorption spectrometry. The influence of alkaline, earth alkaline and some transition metals, as interferents, are discussed. The recoveries for the spiked analytes were greater than 95%. The detection limits for lead and iron by FAAS were 0.37 µg/L and 0.20 µg/L, respectively. Validation of the method described here was performed by using three certified reference materials (SRM 1515 Apple Leaves, SRM 2711 Montana Soil and NRCC-SLRS-4 Riverine Water). The procedure was successfully applied to natural waters and human hair.

Mustafa Soylak; Mustafa Tuzen; Ibrahim Narin

2006-01-01

117

Determination of fluoroquinolones in blood by matrix solid-phase dispersion extraction and CE.  

Science.gov (United States)

A simple and rapid method for the determination of residues of four fluoroquinolones in blood samples was developed. The method was based on matrix solid-phase dispersion extraction followed by CE with ultraviolet detection. 1-Butyl-3-methylimidazolium tetrafluoroborate aqueous solution was used as the background electrolyte for the separation of fluoroquinolones. The average recoveries of the four fluoroquinolones at two spiked levels ranged from 54.0 to 86.4% for pig blood, and 45.4 to 79.9% for deer blood, with the relative standard deviations <9.45%. Detection limits for the four fluoroquinolones in blood sample ranged from 0.15 to 0.31??g/mL. PMID:21374809

Li, Dan; Yang, Qiuling; Wang, Ziming; Su, Rui; Xu, Xu; Zhang, Hanqi

2011-03-04

118

Determination of fluoroquinolones in blood by matrix solid-phase dispersion extraction and CE.  

UK PubMed Central (United Kingdom)

A simple and rapid method for the determination of residues of four fluoroquinolones in blood samples was developed. The method was based on matrix solid-phase dispersion extraction followed by CE with ultraviolet detection. 1-Butyl-3-methylimidazolium tetrafluoroborate aqueous solution was used as the background electrolyte for the separation of fluoroquinolones. The average recoveries of the four fluoroquinolones at two spiked levels ranged from 54.0 to 86.4% for pig blood, and 45.4 to 79.9% for deer blood, with the relative standard deviations <9.45%. Detection limits for the four fluoroquinolones in blood sample ranged from 0.15 to 0.31??g/mL.

Li D; Yang Q; Wang Z; Su R; Xu X; Zhang H

2011-04-01

119

Solid-Phase Extraction and Spectrophotometric Determination of Mercury with 6-Mercaptopurine in Environmental Samples  

International Nuclear Information System (INIS)

[en] A highly selective, sensitive and rapid method for the determination of trace amounts of inorganic mercury based on the reaction of Hg (2) with 6-mercaptopurine and the solid phase extraction of the complex on C18 membrane disks was developed. The 6-mercaptopurine selectively reacts with Hg (2) to form a complex in the pH range of 5-8. This complex was preconcentrated by solid phase extraction with C18 disks. An enrichment factor of 100 was achieved. The molar absorptivity of the complex is 0.26 x10-6 L. mol-1. cm-1 measured at 315 nm. The Beer's law is obeyed in the concentration range of 0.002 - 0.048 ?g mL-1. The relative standard deviation for eleven-replicated measurement of 0.04 ?g mL-1 is 1.5 %. The detection limit is 0.001 ?g mL-1 in the water samples. The advantage of the method is that the determination of Hg (2) is free from interference of almost all the cations and anions found in environment and wastewater samples. The determination of Hg (2) in water samples of different origins and marine sediment were carried out by the present method and cold vapor atomic absorption spectrometry (CVAAS). Also the method's accuracy was investigated by using SRM 2709. The obtained results by the present procedure were in good agreement with those of the CVAAS and certified value, so that the applicability of the proposed method was confirmed for the real samples

2007-01-01

120

Automated mass spectrometric analysis of urinary free catecholamines using on-line solid phase extraction.  

UK PubMed Central (United Kingdom)

Analysis of catecholamines (epinephrine, norepinephrine and dopamine) in plasma and urine is used for diagnosis and treatment of catecholamine-producing tumors. Current analytical techniques for catecholamine quantification are laborious, time-consuming and technically demanding. Our aim was to develop an automated on-line solid phase extraction method coupled to high performance liquid chromatography-tandem mass spectrometry (XLC-MS/MS) for the quantification of free catecholamines in urine. Five microlitre urine equivalent was pre-purified by automated on-line solid phase extraction, using phenylboronic acid complexation. Reversed phase (pentafluorophenylpropyl column) chromatography was applied. Mass spectrometric detection was operated in multiple reaction monitoring mode using a quadrupole tandem mass spectrometer with positive electrospray ionization. Urinary reference intervals were set in 24-h urine collections of 120 healthy subjects. XLC-MS/MS was compared with liquid chromatography with electrochemical detection (HPLC-ECD). Total run-time was 14 min. Intra- and inter-assay analytical variations were <10%. Linearity was excellent (R2>0.99). Quantification limits were 1.47 nmol/L, 15.8 nmol/L and 11.7 nmol/L for epinephrine, norepinephrine and dopamine, respectively. XLC-MS/MS correlated well with HPLC-ECD (correlation coefficient >0.98). Reference intervals were 1-10 micromol/mol, 10-50 micromol/mol and 60-225 micromol/mol creatinine for epinephrine, norepinephrine and dopamine, respectively. Advantages of the XLC-MS/MS catecholamine method include its high analytical performance by selective PBA affinity and high specificity and sensitivity by unique MS/MS fragmentation.

de Jong WH; de Vries EG; Wolffenbuttel BH; Kema IP

2010-06-01

 
 
 
 
121

Molecularly imprinted sol-gel silica for solid phase extraction of phenobarbital  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Sílica organicamente modificada e molecularmente impressa foi preparada através de um procedimento sol-gel simples, e avaliada como sorvente específico para extração em fase sólida (Solid Phase Extraction, SPE) de fenobarbital em amostras aquosas e forenses. As propriedades analíticas dessa sílica molecularmente impressa (MIS, molecularly imprinted silica) foram inicialmente avaliadas e o material determinado como específico para as espécies-alvo: o fator de imp (more) ressão IF, medido como a razão entre o pico do fenobarbital em cromatogramas de MIS e NIS (sílica não-impressa) foi estimado como 58. Este valor é consideravelmente maior que aquele apresentado normalmente para sorventes de impressão convencional baseados em metacrilatos e sugere que interações não-específicas analito/sorvente são insignificantes no MIS. O material foi aplicado no isolamento de fenobarbital de amostras aquosas e plasma; limites de detecção de 10 e 62 µg mL-1, respectivamente, foram encontrados para essas amostras. Abstract in english A molecularly imprinted organically modified silica was prepared through a simple sol-gel procedure, and evaluated as specific sorbent for solid-phase extraction (SPE) of phenobarbital from aqueous and forensic samples. The analytical properties of the molecularly imprinted silica (MIS, non-imprinted sílica) were initially evaluated and the MIS was found to be specific towards the target species: the imprinting factor IF, measured as the ratio between phenobarbital peak (more) areas in the MIS and NIS chromatograms, was estimated as 58. This value is considerably higher than those usually found for conventional methacrylate-based molecularly imprinted sorbents and suggests that non-specific analyte/sorbent interactions are insignificant in the MIS. This material is applied to the isolation of phenobarbital from aqueous samples and plasma; detection limit of 10 and 62 µg mL-1 was achieved for the former samples, respectively.

Pilau, Eduardo J.; Silva, Raquel G. C.; Jardim, Isabel C. F. S.; Augusto, Fabio

2008-01-01

122

Determination of colloidal and dissolved silver in water samples using colorimetric solid-phase extraction.  

UK PubMed Central (United Kingdom)

The increase in bacterial resistance to antibiotics has led to resurgence in the use of silver as a biocidal agent in applications ranging from washing machine additives to the drinking water treatment system on the International Space Station (ISS). However, growing concerns about the possible toxicity of colloidal silver to bacteria, aquatic organisms and humans have led to recently issued regulations by the US EPA and FDA regarding the usage of silver. As part of an ongoing project, we have developed a rapid, simple method for determining total silver, both ionic (silver(I)) and colloidal, in 0.1-1mg/L aqueous samples, which spans the ISS potable water target of 0.3-0.5mg/L (total silver) and meets the US EPA limit of 0.1mg/L in drinking water. The method is based on colorimetric solid-phase extraction (C-SPE) and involves the extraction of silver(I) from water samples by passage through a solid-phase membrane impregnated with the colorimetric reagent DMABR (5-[4-(dimethylamino)benzylidene]rhodanine). Silver(I) exhaustively reacts with impregnated DMABR to form a colored compound, which is quantified using a handheld diffuse reflectance spectrophotometer. Total silver is determined by first passing the sample through a cartridge containing Oxone, which exhaustively oxidizes colloidal silver to dissolved silver(I). The method, which takes less than 2 min to complete and requires only approximately 1 mL of sample, has been validated through a series of tests, including a comparison with the ICP-MS analysis of a water sample from ISS that contained both silver(I) and colloidal silver. Potential earth-bound applications are also briefly discussed.

Hill AA; Lipert RJ; Porter MD

2010-03-01

123

Molecularly imprinted solid-phase extraction for the screening of antihyperglycemic biguanides.  

Science.gov (United States)

A new molecularly imprinted polymer (MIP) was specifically synthesized as a smart material for the recognition of metformin hydrochloride in solid-phase extraction. Particles of this MIP were packed into a stainless-steel tubing (50 mm x 0.8 mm i.d.) equipped with an exit frit. This micro-column was employed in the development of a molecularly imprinted solid-phase extraction (MISPE) method for metformin determination. The MISPE instrumentation consisted of a micrometer pump, an injector valve equipped with a 20-microl sample loop, a UV detector, and an integrator. With CH3CN as the mobile phase flowing at 0.5 ml/min, 95 +/- 2% binding could be achieved for 1200 ng of metformin from one injection of a phosphate-buffered sample solution (pH 2.5). Methanol + 3% trifluoroacetic acid was good for quantitative pulsed elution (PE) of the bound metformin. The MISPE-PE method, with UV detection at 240 nm, afforded a detection limit of 16 ng (or 0.8 microg/ml) for metformin. However, the micro-column interacted indiscriminately with phenformin with a 49 +/- 2% binding. A systematic investigation of binding selectivity was conducted with respect to sample composition (including the solvent, matrix, pH, buffer and surfactant effects). An intermediate step of differential pulsed elution used acetonitrile with 5% picric acid to remove phenformin and other structural analogues. A final pulsed elution of metformin for direct UV detection was achieved using 3% trifluoroacetic acid in methanol. PMID:14971497

Feng, Sherry Y; Lai, Edward P C; Dabek-Zlotorzynska, Ewa; Sadeghi, Susan

2004-02-20

124

Molecularly imprinted solid-phase extraction for the screening of antihyperglycemic biguanides.  

UK PubMed Central (United Kingdom)

A new molecularly imprinted polymer (MIP) was specifically synthesized as a smart material for the recognition of metformin hydrochloride in solid-phase extraction. Particles of this MIP were packed into a stainless-steel tubing (50 mm x 0.8 mm i.d.) equipped with an exit frit. This micro-column was employed in the development of a molecularly imprinted solid-phase extraction (MISPE) method for metformin determination. The MISPE instrumentation consisted of a micrometer pump, an injector valve equipped with a 20-microl sample loop, a UV detector, and an integrator. With CH3CN as the mobile phase flowing at 0.5 ml/min, 95 +/- 2% binding could be achieved for 1200 ng of metformin from one injection of a phosphate-buffered sample solution (pH 2.5). Methanol + 3% trifluoroacetic acid was good for quantitative pulsed elution (PE) of the bound metformin. The MISPE-PE method, with UV detection at 240 nm, afforded a detection limit of 16 ng (or 0.8 microg/ml) for metformin. However, the micro-column interacted indiscriminately with phenformin with a 49 +/- 2% binding. A systematic investigation of binding selectivity was conducted with respect to sample composition (including the solvent, matrix, pH, buffer and surfactant effects). An intermediate step of differential pulsed elution used acetonitrile with 5% picric acid to remove phenformin and other structural analogues. A final pulsed elution of metformin for direct UV detection was achieved using 3% trifluoroacetic acid in methanol.

Feng SY; Lai EP; Dabek-Zlotorzynska E; Sadeghi S

2004-02-01

125

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 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.

2012-10-24

126

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

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer The use of CNTs as sorbent for metal species in solid phase extraction has been described. Black-Right-Pointing-Pointer Physical and chemical strategies for functionalization of carbon nanotubes have been discussed. Black-Right-Pointing-Pointer 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 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.

Herrero Latorre, C., E-mail: carlos.herrero@usc.es [Universidad de Santiago de Compostela, Dpto. Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Alfonso X el Sabio s/n, 27002 Lugo (Spain); Alvarez Mendez, J.; Barciela Garcia, J.; Garcia Martin, S.; Pena Crecente, R.M. [Universidad de Santiago de Compostela, Dpto. Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Alfonso X el Sabio s/n, 27002 Lugo (Spain)

2012-10-24

127

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

2011-03-07

128

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

UK PubMed Central (United Kingdom)

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.

Shen ZL; Yuan D; Su QD; Zhang H; Wang J; Zhu JH; Liu YM

2011-01-01

129

Determination of triazine herbicides using membrane-protected carbon nanotubes solid phase membrane tip extraction prior to micro-liquid chromatography.  

UK PubMed Central (United Kingdom)

A novel microextraction technique termed solid phase membrane tip extraction (SPMTE) was developed. Selected triazine herbicides were employed as model compounds to evaluate the extraction performance and multiwall carbon nanotubes (MWCNTs) were used as the adsorbent enclosed in SPMTE device. The SPMTE procedure was performed in semi-automated dynamic mode and several important extraction parameters were comprehensively optimized. Under the optimum extraction conditions, the method showed good linearity in the range of 1-100 microg/L, acceptable reproducibility (RSD 6-8%, n=5), low limits of detection (0.2-0.5 microg/L), and satisfactory relative recoveries (95-101%). The SPMTE device could be regenerated and reused up to 15 analyses with no analyte carry-over effects observed. Comparison was made with commercially available solid phase extraction-molecular imprinted polymer cartridge (SPE-MIP) for triazine herbicides as the reference method. The new developed method showed comparable or even better results against reference method and is a simple, feasible, and cost effective microextraction technique.

See HH; Marsin Sanagi M; Ibrahim WA; Naim AA

2010-03-01

130

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)

2002-07-03

131

Application of solid-phase extraction to agar-supported fermentation.  

UK PubMed Central (United Kingdom)

Agar-supported fermentation (Ag-SF), a variant of solid-state fermentation, has recently been improved by the development of a dedicated 2 m(2) scale pilot facility, Platotex. We investigated the application of solid-phase extraction (SPE) to Ag-SF in order to increase yields and minimize the contamination of the extracts with agar constituents. The selection of the appropriate resin was conducted on liquid-state fermentation and Diaion HP-20 exhibited the highest recovery yield and selectivity for the metabolites of the model fungal strains Phomopsis sp. and Fusarium sp. SPE applied to Ag-SF resulted in a particular compartmentalization of the culture. The mycelium that requires oxygen to grow migrates to the top layer and formed a thick biofilm. The resin beads intercalate between the agar surface and the mycelium layer, and trap directly the compounds secreted by the mycelium through a "solid-solid extraction" (SSE) process. The resin/mycelium layer is easily recovered by scraping the surface and the target metabolites extracted by methanol. Ag-SF associated to SSE represents an ideal compromise for the production of bioactive secondary metabolites with limited economic and environmental impact.

Le Goff G; Adelin E; Cortial S; Servy C; Ouazzani J

2013-09-01

132

Application of solid-phase extraction to agar-supported fermentation.  

Science.gov (United States)

Agar-supported fermentation (Ag-SF), a variant of solid-state fermentation, has recently been improved by the development of a dedicated 2 m(2) scale pilot facility, Platotex. We investigated the application of solid-phase extraction (SPE) to Ag-SF in order to increase yields and minimize the contamination of the extracts with agar constituents. The selection of the appropriate resin was conducted on liquid-state fermentation and Diaion HP-20 exhibited the highest recovery yield and selectivity for the metabolites of the model fungal strains Phomopsis sp. and Fusarium sp. SPE applied to Ag-SF resulted in a particular compartmentalization of the culture. The mycelium that requires oxygen to grow migrates to the top layer and formed a thick biofilm. The resin beads intercalate between the agar surface and the mycelium layer, and trap directly the compounds secreted by the mycelium through a "solid-solid extraction" (SSE) process. The resin/mycelium layer is easily recovered by scraping the surface and the target metabolites extracted by methanol. Ag-SF associated to SSE represents an ideal compromise for the production of bioactive secondary metabolites with limited economic and environmental impact. PMID:23263569

Le Goff, Géraldine; Adelin, Emilie; Cortial, Sylvie; Servy, Claudine; Ouazzani, Jamal

2012-12-23

133

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

UK PubMed Central (United Kingdom)

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.

Riachi LG; Abi-Zaid IE; Moreira RF; De Maria CA

2012-12-01

134

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

135

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

UK PubMed Central (United Kingdom)

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 samples is presented. An imprinted polymer with molecular recognition properties for BPA was prepared in acetonitrile by thermal polymerization of a mixture of 4,4'-dihydroxy-2,2-diphenyl-1,1,1,3,3,3-trifluoropropane as a mimic template of BPA, 4-vinylpyridine and trimethylolpropane trimethacrylate in a molar ratio of 1 + 6 + 6. Fine imprinted particles (<10 microm) were embedded in a poly-acrylamide-co-N,N'-methylenbisacrylamide cryogel obtained by ammonium persulfate-induced cryopolymerization at -18 degrees C. The resulting monolithic gel was evaluated for its use as a sorbent support in an off-line solid-phase extraction approach to recover BPA from dilute aqueous samples with minimum pre-loading work-up. The optimized extraction protocol resulted in a reliable MISPE method suitable to selectively extract and preconcentrate BPA from river water and red wine samples, demonstrating the practical feasibility of cryogel-trapped imprinted polymers as solid-phase extraction materials.

Baggiani C; Baravalle P; Giovannoli C; Anfossi L; Giraudi G

2010-05-01

136

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

Science.gov (United States)

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 samples is presented. An imprinted polymer with molecular recognition properties for BPA was prepared in acetonitrile by thermal polymerization of a mixture of 4,4'-dihydroxy-2,2-diphenyl-1,1,1,3,3,3-trifluoropropane as a mimic template of BPA, 4-vinylpyridine and trimethylolpropane trimethacrylate in a molar ratio of 1 + 6 + 6. Fine imprinted particles (ammonium persulfate-induced cryopolymerization at -18 degrees C. The resulting monolithic gel was evaluated for its use as a sorbent support in an off-line solid-phase extraction approach to recover BPA from dilute aqueous samples with minimum pre-loading work-up. The optimized extraction protocol resulted in a reliable MISPE method suitable to selectively extract and preconcentrate BPA from river water and red wine samples, demonstrating the practical feasibility of cryogel-trapped imprinted polymers as solid-phase extraction materials. PMID:20225052

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

2010-03-12

137

Quantification of limonin in human urine using solid-phase extraction by LC-MS/MS.  

Science.gov (United States)

A highly sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of limonin in human urine using podophyllotoxin as internal standard. The analyte and IS were extracted with solid-phase extraction and separated by a rapid isocratic elution with 1% formic acid/methanol (v:v, 40:60) on an C(18) column (150 mm × 2.1 mm I.D.). The detection was performed by mass spectrometry in the multi-reaction-monitoring mode. The precursor to product ion transitions of m/z 471.3?161.2 and m/z 397.2?313.1 were used to measure the analyte and the IS. The assay was linear over the concentration range of 0.0783-10 ng/mL for limonin in human urine. The lower limit of quantification was 0.0783 ng/mL and the extraction recovery was larger than 76.7% for limonin. The inter- and intra-day precision of the method at three concentrations was less than 7.4%. The method was successfully applied to pharmacokinetic study of limonin in humans. PMID:22999474

Liu, Shijia; Zhang, Jun; Zhou, Ling; Yu, Boyang; Li, Changyin; Liu, Zixiu; Ju, Wenzheng

2012-09-07

138

Quantification of limonin in human urine using solid-phase extraction by LC-MS/MS.  

UK PubMed Central (United Kingdom)

A highly sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of limonin in human urine using podophyllotoxin as internal standard. The analyte and IS were extracted with solid-phase extraction and separated by a rapid isocratic elution with 1% formic acid/methanol (v:v, 40:60) on an C(18) column (150 mm × 2.1 mm I.D.). The detection was performed by mass spectrometry in the multi-reaction-monitoring mode. The precursor to product ion transitions of m/z 471.3?161.2 and m/z 397.2?313.1 were used to measure the analyte and the IS. The assay was linear over the concentration range of 0.0783-10 ng/mL for limonin in human urine. The lower limit of quantification was 0.0783 ng/mL and the extraction recovery was larger than 76.7% for limonin. The inter- and intra-day precision of the method at three concentrations was less than 7.4%. The method was successfully applied to pharmacokinetic study of limonin in humans.

Liu S; Zhang J; Zhou L; Yu B; Li C; Liu Z; Ju W

2012-10-01

139

[Optimization of solid-phase extraction for enrichment of toxic organic compounds in water samples].  

Science.gov (United States)

A concentration method for enrichment of toxic organic compounds in water samples has been developed based on combined solid-phase extraction (SPE) to reduce impurities and improve recoveries of target compounds. This SPE method was evaluated in every stage to identify the source of impurities. Based on the analysis of Waters Oasis HLB without water samples, the eluent of SPE sorbent after dichloromethane and acetone contributed 85% of impurities during SPE process. In order to reduce the impurities from SPE sorbent, soxhlet extraction of dichloromethane followed by acetone and lastly methanol was applied to the sorbents for 24 hours and the results had proven that impurities were reduced significantly. In addition to soxhlet extraction, six types of prevalent SPE sorbents were used to absorb 40 target compounds, the lgK(ow) values of which were within the range of 1.46 and 8.1, and recovery rates were compared. It was noticed and confirmed that Waters Oasis HLB had shown the best recovery results for most of the common testing samples among all three styrenedivinylbenzene (SDB) polymer sorbents, which were 77% on average. Furthermore, Waters SepPak AC-2 provided good recovery results for pesticides among three types of activated carbon sorbents and the average recovery rates reached 74%. Therefore, Waters Oasis HLB and Waters SepPak AC-2 were combined to obtain a better recovery and the average recovery rate for the tested 40 compounds of this new SPE method was 87%. PMID:23914538

Zhang, Ming-quan; Li, Feng-min; Wu, Qian-yuan; Hu, Hong-ying

2013-05-01

140

[Optimization of solid-phase extraction for enrichment of toxic organic compounds in water samples].  

UK PubMed Central (United Kingdom)

A concentration method for enrichment of toxic organic compounds in water samples has been developed based on combined solid-phase extraction (SPE) to reduce impurities and improve recoveries of target compounds. This SPE method was evaluated in every stage to identify the source of impurities. Based on the analysis of Waters Oasis HLB without water samples, the eluent of SPE sorbent after dichloromethane and acetone contributed 85% of impurities during SPE process. In order to reduce the impurities from SPE sorbent, soxhlet extraction of dichloromethane followed by acetone and lastly methanol was applied to the sorbents for 24 hours and the results had proven that impurities were reduced significantly. In addition to soxhlet extraction, six types of prevalent SPE sorbents were used to absorb 40 target compounds, the lgK(ow) values of which were within the range of 1.46 and 8.1, and recovery rates were compared. It was noticed and confirmed that Waters Oasis HLB had shown the best recovery results for most of the common testing samples among all three styrenedivinylbenzene (SDB) polymer sorbents, which were 77% on average. Furthermore, Waters SepPak AC-2 provided good recovery results for pesticides among three types of activated carbon sorbents and the average recovery rates reached 74%. Therefore, Waters Oasis HLB and Waters SepPak AC-2 were combined to obtain a better recovery and the average recovery rate for the tested 40 compounds of this new SPE method was 87%.

Zhang MQ; Li FM; Wu QY; Hu HY

2013-05-01

 
 
 
 
141

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

International Nuclear Information System (INIS)

[en] 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)

2008-01-01

142

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

Directory of Open Access Journals (Sweden)

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; M. JACQUELINE SEPÚLVEDA C; CARLOS VON PLESSING R

2011-01-01

143

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

Scientific Electronic Library Online (English)

Full Text Available 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 p (more) H 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.

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

2011-01-01

144

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

UK PubMed Central (United Kingdom)

ZnO nanorod array coating is a novel kind of solid-phase microextraction (SPME) fiber coating which shows good extraction capability due to the nanostructure. To prepare the composite coating is a good way to improve the extraction capability. In this paper, the ZnO nanorod array polydimethylsiloxane (PDMS) composite SPME fiber coating has been prepared and its extraction capability for volatile organic compounds (VOCs) has been studied by headspace sampling the typical volatile mixed standard solution of benzene, toluene, ethylbenzene and xylene (BTEX). Improved detection limit and good linear ranges have been achieved for this composite SPME fiber coating. Also, it is found that the composite SPME fiber coating shows good extraction selectivity to the VOCs with alkane radicals.

Wang D; Wang Q; Zhang Z; Chen G

2012-01-01

145

Determination of crystal violet in water by direct solid phase spectrophotometry after rotating disk sorptive extraction.  

UK PubMed Central (United Kingdom)

The microextraction of crystal violet (CV) from water samples into polydimethylsiloxane (PDMS) using the rotating disk sorptive extraction (RDSE) technique was performed. The extracting device was a small Teflon disk that had an embedded miniature magnetic stirring bar and a PDMS (560 ?L) film attached to one side of the disk using double-sided tape. The extraction involves a preconcentration of CV into the PDMS, where the analyte is then directly quantified using solid phase spectrophotometry at 600 nm. Different chemical and extraction device-related variables were studied to achieve the best sensitivity for the determination. The optimum extraction was performed at pH 14 because under this condition, CV is transformed to the neutral and colorless species carbinol, which can be quantitatively transferred to the PDMS phase. Although the colorless species is the chemical form extracted in the PDMS, an intense violet coloration appeared in the phase because the -OH bond in the carbinol molecule is weakened through the formation of hydrogen bonds with the oxygen atoms of the PDMS, allowing the resonance between the three benzene rings to compensate for the charge deficit on the central carbon atom of the molecule. The accuracy and precision of the method were evaluated in river water samples spiked with 10 and 30 ?g L(-1) of CV, yielding a relative standard deviation of 6.2% and 8.4% and a recovery of 98.4% and 99.4%, respectively. The method detection limit was 1.8 ?g L(-1) and the limit of quantification was 5.4 ?g L(-1), which can be decreased if the sample volume is increased.

Manzo V; Navarro O; Honda L; Sánchez K; Inés Toral M; Richter P

2013-03-01

146

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.

2009-09-03

147

Solid-phase extraction and capillary electrophoresis determination of phenols from soil after alkaline CuO oxidation.  

UK PubMed Central (United Kingdom)

Alkaline CuO oxidation has been used on molecular-level analyses of phenols from organic matter in the last decades. This method, originally developed by Hedges and Ertel [Hedges, J.I., Ertel, J.R., 1982. Characterization of lignin by gas capillary chromatography of cupric oxide oxidation products. Anal. Chem. 54, 174-178] has several drawbacks that have limited is wider utilization. In this paper, we propose a modification of the method using a solid-phase extraction (SPE) instead of a liquid-liquid extraction. The SPE procedure using C18 cartridges was optimized to obtain high recoveries. The sequential elution with acetonitrile and methanol was found to be the most appropriate procedure. Recoveries of the 12 phenols in individual standard solutions ranged from 84% to 113% with relative standard deviation (RSD) lower than 12%. Experiments with a mixed standard solution highlighted the competition between the different phenols for the adsorbing sites. Recoveries decreased with polarity, reaching 30% for p-hydroxybenzoic acid when present at a concentration of 2.5 x 10(-3)M. A sample soil subjected to a CuO oxidation was used to test the reproducibility of the SPE method and good results were achieved, RSD ranged between 0.4% and 28.3%. The performance of the CE method was also evaluated by correlation coefficients (higher than 0.9920), linearity (higher than 99.902%) and limit of detection (ranging from 2.64 x 10(-6) to 1.25 x 10(-5)M). SPE procedure presents several advantages such as fast sample preparation, good recoveries, good accuracy, low sample handling and safety improvement due to reduced solvent/sample exposure and glassware management.

Lima DL; Duarte AC; Esteves VI

2007-09-01

148

Use of itaconic acid-based polymers for solid-phase extraction of deoxynivalenol and application to pasta analysis.  

Science.gov (United States)

Molecular modelling and computational design were used to identify itaconic acid (IA) as a functional monomer with high affinity towards deoxynivalenol (DON), a Fusarium-toxin frequently occurring in cereals. IA-based polymers were photochemically synthesised in dimethyl formamide (porogen) using ethylenglycol dimethacrylate as cross-linker and 1,1'-azo-bis(cyclohexane carbonitrile) as initiator, and the relevant binding interactions with DON in solvents with different polarity were investigated. The performances of the non-imprinted IA-based polymer (blank polymer, BP) and the corresponding molecularly imprinted polymer (MIP) were compared using DON as a template. Both BP and MIP were able to bind about 90% DON either in toluene, water or water containing 5% polyethylene glycol. Non-imprinted polymers with different molar ratios of IA to cross-linker were evaluated as adsorbents for solid-phase extraction (SPE) clean-up and pre-concentration of DON from wheat and pasta samples prior to HPLC analysis. Samples were extracted with PBS/0.1M EDTA solution and cleaned up through a cartridge containing blank IA-based polymer. The column was washed with PBS (pH 9.2) and the toxin was eluted with methanol and quantified by reversed-phase HPLC with UV detector (lambda=220nm), using methanol:water:acetic acid (15:85:0.1, v/v/v) as the mobile phase. Effective removal of matrix interferences was observed only for pasta with DON recoveries higher than 70% (RSD<7%, n=3) at levels close to or higher than EU regulatory limit. PMID:18261508

Pascale, Michelangelo; De Girolamo, Annalisa; Visconti, Angelo; Magan, Naresh; Chianella, Iva; Piletska, Elena V; Piletsky, Sergey A

2008-01-10

149

Determination of organic acids in Salicornia herbacea by solid-phase extraction combined with liquid chromatography.  

UK PubMed Central (United Kingdom)

A solid-phase extraction (SPE) method for the determination of procatechuic acid, ferulic acid and caffeic acid in Salicornia herbacea L. (Hamcho) has been developed. The optimal conditions were obtained by using a C18 SPE cartridge. By using ethanol and acetonitrile /water/ trifluoracetic acid as washing and eluting solvents, most interfering compounds originating from the hamcho matrix were eliminated. The extracts were sufficiently clean to be directly injected into the HPLC for further chromatographic analysis. Good linearity was obtained from 0.1 to 200 microg/mL (r > 0.999) for procatechuic acid, 0.2 to 400 microg/mL (r > 0.999) for caffeic acid and 0.3 to 600 microg/mL (r > 0.999) for ferulic acid, with the relative standard deviations being less than 3.6%. The mean recoveries of procatechuic acid, ferulic acid and caffeic acid from hamcho were more than 79.2% and the detection limit (S/N = 3:1) was 0.02 microg/mL for procatechuic acid, 0.01 microg/mL for caffeic acid and 0.04 microg/mL for ferulic acid. This method is a viable alternative to the existing HPLC methods for analyzing the content of procatechuic acid, ferulic acid and caffeic acid in hamcho.

Han D; Tian M; Park DW; Row KH

2013-02-01

150

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

International Nuclear Information System (INIS)

[en] 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)

2003-01-01

151

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

Energy Technology Data Exchange (ETDEWEB)

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{sup -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{sup -3}. Some concomitant ions such as Cd{sup 2+}, Ni{sup 2+}, MoO{sub 4}{sup 2-}, Cu{sup 2+}, Th{sup 4+} and Ce{sup 3+}, 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)

Farzaneh Shemirani; Shiva Dehghan Abkenar; Mohammad Reza Jamali [University of Tehran, Faculty of Science, Tehran (Iran)

2003-03-01

152

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; M. Khadem; F. Golbabaei; A. Rahimi-Froushani

2007-01-01

153

Determination of organic acids in Salicornia herbacea by solid-phase extraction combined with liquid chromatography.  

Science.gov (United States)

A solid-phase extraction (SPE) method for the determination of procatechuic acid, ferulic acid and caffeic acid in Salicornia herbacea L. (Hamcho) has been developed. The optimal conditions were obtained by using a C18 SPE cartridge. By using ethanol and acetonitrile /water/ trifluoracetic acid as washing and eluting solvents, most interfering compounds originating from the hamcho matrix were eliminated. The extracts were sufficiently clean to be directly injected into the HPLC for further chromatographic analysis. Good linearity was obtained from 0.1 to 200 microg/mL (r > 0.999) for procatechuic acid, 0.2 to 400 microg/mL (r > 0.999) for caffeic acid and 0.3 to 600 microg/mL (r > 0.999) for ferulic acid, with the relative standard deviations being less than 3.6%. The mean recoveries of procatechuic acid, ferulic acid and caffeic acid from hamcho were more than 79.2% and the detection limit (S/N = 3:1) was 0.02 microg/mL for procatechuic acid, 0.01 microg/mL for caffeic acid and 0.04 microg/mL for ferulic acid. This method is a viable alternative to the existing HPLC methods for analyzing the content of procatechuic acid, ferulic acid and caffeic acid in hamcho. PMID:23513729

Han, Dandan; Tian, Minglei; Park, Dong Wha; Row, Kyung Ho

2013-02-01

154

Dynamic solid phase DNA extraction and PCR amplification in polyester-toner based microchip.  

Science.gov (United States)

A variety of substrates have been used for fabrication of microchips for DNA extraction, PCR amplification, and DNA fragment separation, including the more conventional glass and silicon as well as alternative polymer-based materials. Polyester represents one such polymer, and the laser-printing of toner onto polyester films has been shown to be effective for generating polyester-toner (PeT) microfluidic devices with channel depths on the order of tens of micrometers. Here, we describe a novel and simple process that allows for the production of multilayer, high aspect-ratio PeT microdevices with substantially larger channel depths. This innovative process utilizes a CO(2) laser to create the microchannel in polyester sheets containing a uniform layer of printed toner, and multilayer devices can easily be constructed by sandwiching the channel layer between uncoated cover sheets of polyester containing precut access holes. The process allows the fabrication of deep channels, with ~270 ?m, and we demonstrate the effectiveness of multilayer PeT microchips for dynamic solid phase extraction (dSPE) and PCR amplification. With the former, we found that (i) more than 65% of DNA from 0.6 ?L of blood was recovered, (ii) the resultant DNA was concentrated to greater than 3 ng/?L (which was better than other chip-based extraction methods), and (iii) the DNA recovered was compatible with downstream microchip-based PCR amplification. Illustrative of the compatibility of PeT microchips with the PCR process, the successful amplification of a 520 bp fragment of ?-phage DNA in a conventional thermocycler is shown. The ability to handle the diverse chemistries associated with DNA purification and extraction is a testimony to the potential utility of PeT microchips beyond separations and presents a promising new disposable platform for genetic analysis that is low cost and easy to fabricate. PMID:21557576

Duarte, Gabriela R M; Price, Carol W; Augustine, Brian H; Carrilho, Emanuel; Landers, James P

2011-06-03

155

Dynamic solid phase DNA extraction and PCR amplification in polyester-toner based microchip.  

UK PubMed Central (United Kingdom)

A variety of substrates have been used for fabrication of microchips for DNA extraction, PCR amplification, and DNA fragment separation, including the more conventional glass and silicon as well as alternative polymer-based materials. Polyester represents one such polymer, and the laser-printing of toner onto polyester films has been shown to be effective for generating polyester-toner (PeT) microfluidic devices with channel depths on the order of tens of micrometers. Here, we describe a novel and simple process that allows for the production of multilayer, high aspect-ratio PeT microdevices with substantially larger channel depths. This innovative process utilizes a CO(2) laser to create the microchannel in polyester sheets containing a uniform layer of printed toner, and multilayer devices can easily be constructed by sandwiching the channel layer between uncoated cover sheets of polyester containing precut access holes. The process allows the fabrication of deep channels, with ~270 ?m, and we demonstrate the effectiveness of multilayer PeT microchips for dynamic solid phase extraction (dSPE) and PCR amplification. With the former, we found that (i) more than 65% of DNA from 0.6 ?L of blood was recovered, (ii) the resultant DNA was concentrated to greater than 3 ng/?L (which was better than other chip-based extraction methods), and (iii) the DNA recovered was compatible with downstream microchip-based PCR amplification. Illustrative of the compatibility of PeT microchips with the PCR process, the successful amplification of a 520 bp fragment of ?-phage DNA in a conventional thermocycler is shown. The ability to handle the diverse chemistries associated with DNA purification and extraction is a testimony to the potential utility of PeT microchips beyond separations and presents a promising new disposable platform for genetic analysis that is low cost and easy to fabricate.

Duarte GR; Price CW; Augustine BH; Carrilho E; Landers JP

2011-07-01

156

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

Scientific Electronic Library Online (English)

Full Text Available 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 monitoramento de íons selecionados (GC-SIM-MS). As condições experimentais para a extração e derivatização foram otimizadas utilizando procedimentos quimiométricos, s (more) endo 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 leather samples. The extraction and derivatization conditions were optimized using experimental designs, such as: extraction time and sample temperature of 5 min and 170 ºC, fibe (more) r 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.

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

2012-12-01

157

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

UK PubMed Central (United Kingdom)

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.

He Z; Liu D; Li R; Zhou Z; Wang P

2012-10-01

158

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

2012-08-27

159

Preparation and evaluation of molecularly imprinted polymer of olivetol for solid phase extraction.  

UK PubMed Central (United Kingdom)

Molecularly imprinted polymer (MIP) was synthesized by bulk polymerization, using olivetol as template molecule, methyl acrylic acid (MAA) as monomer, ethylene glycol dimethacrylate (EDMA) as crosslinker, toluene and dodecanol as solvents. The resulted MIP was characterized by the equilibrium binding experiments, scanning electron microscope (SEM) and Fourier transform infrared spectrometer (FTIR). The polymer was then applied to solid phase extraction (SPE) of olivetol from spiked wheat bran samples. From the equilibrium binding experiments, it was showed that MIP had a better recognizability for the template molecule. Scatchard analysis showed that MIP had specific adsorption to olivetol with two classes of binding sites. The high and low binding sites dissociation constants were 0.021 and 1.002 mmol/L. The corresponding maximum binding capacities were 18.74 and 135.9 micromol/g, respectively. Under the optimum condition of SPE, the recoveries of olivetol on MIP cartridge were in the range of 97.8% - 98.8%. The relative standard deviations (RSDs) were 2.8% -4.2%. The linearity range was between 0.1 and 100 mg/L. The limit of detection (S/N = 3) was 0.062 mg/L. MIP cartridge showed stronger selectivity, higher recovery and purified the sample more drastically compared with non-imprinted polymer (NIP) cartridge and commercial poly (styrene/divinyl-benzene) (PLS) cartridge.

Jin Y; Chen N; Liu R; Chen J; Bai L; Zhang Y

2013-06-01

160

Preparation and evaluation of molecularly imprinted polymer of olivetol for solid phase extraction.  

Science.gov (United States)

Molecularly imprinted polymer (MIP) was synthesized by bulk polymerization, using olivetol as template molecule, methyl acrylic acid (MAA) as monomer, ethylene glycol dimethacrylate (EDMA) as crosslinker, toluene and dodecanol as solvents. The resulted MIP was characterized by the equilibrium binding experiments, scanning electron microscope (SEM) and Fourier transform infrared spectrometer (FTIR). The polymer was then applied to solid phase extraction (SPE) of olivetol from spiked wheat bran samples. From the equilibrium binding experiments, it was showed that MIP had a better recognizability for the template molecule. Scatchard analysis showed that MIP had specific adsorption to olivetol with two classes of binding sites. The high and low binding sites dissociation constants were 0.021 and 1.002 mmol/L. The corresponding maximum binding capacities were 18.74 and 135.9 micromol/g, respectively. Under the optimum condition of SPE, the recoveries of olivetol on MIP cartridge were in the range of 97.8% - 98.8%. The relative standard deviations (RSDs) were 2.8% -4.2%. The linearity range was between 0.1 and 100 mg/L. The limit of detection (S/N = 3) was 0.062 mg/L. MIP cartridge showed stronger selectivity, higher recovery and purified the sample more drastically compared with non-imprinted polymer (NIP) cartridge and commercial poly (styrene/divinyl-benzene) (PLS) cartridge. PMID:24063201

Jin, Yafeng; Chen, Na; Liu, Runqiang; Chen, Jun; Bai, Lianyang; Zhang, Yuping

2013-06-01

 
 
 
 
161

Stability of pesticides stored on polymeric solid-phase extraction cartridges.  

UK PubMed Central (United Kingdom)

The stability of four pesticides (desethylatrazine, fenamiphos, fenitrothion and fonofos) was examined under different storage conditions after preconcentration in disposable solid-phase extraction (SPE) cartridges containing new polymer sorbent materials (Hysphere-1, IST EnviroLut and LiChrolut). Complete recovery for all the compounds was observed in precolumns kept at -20 degrees C for 1 month when preconcentrating 26 ml of ground water sample spiked at 10 micrograms/l. Degradation of fenamiphos and fenitrothion occurred in precolumns stored at 4 degrees C and at room temperature after 1 month. Fonofos was stable when compared to their storage in C18 precolumns. Problems in the quantification of the analytes after storage at 4 degrees C and at room temperature were encountered due to the presence of many interfering peaks in the chromatograms. Analysis of blanks with C18 precolumns was carried out, to determine the interferences. The stability of the pesticides was also examined in acidifed and non-acidified ground water in order to compare it to the stability of pesticides stored on SPE cartridges. Significant losses of fenamiphos and fenitrothion were achieved and were related to the pH of the water sample and their chemical structure. Finally, the new polymeric sorbent Hysphere-I was evaluated in terms of breakthroughs and compared with those of C18, obtaining higher recoveries for desethylatrazine.

Ferrer I; Barceló D

1997-08-01

162

Solid Phase Extraction and spectrophotometric determination of palladium using hexyl benzimidazolyl sulfide as a chromogenic agent  

International Nuclear Information System (INIS)

Synthesis and application of hexyl benzimidazolyl sulfide (HBMS) as a new chromogenic reagent for determination of palladium has been described. Highly sensitive, selective, and fast method for determination of palladium based on its rapid reaction with HBMS and solid phase extraction of the colored complex on the CLEAN-UP C8 cartridge has been developed. In the presence of 0.01-0.1 mol L-1 HCl solution and polyoxyethylene-nonylphenol ether (emulsifier-OP) medium, HBMS reacted with palladium to form colored complex of palladium-to-HBMS molar ratio of 1:2. The crystal structure of the Pd(II)-HBMS complex has been determined using single-crystal X-ray diffraction. The complex was eluted from the cartridge with N,N-dimethylformamide (DMF) and enrichment factor of 50 was achieved. In DMF medium, molar absorptivity of the complex was 2.08 x 105 L mol-1 cm-1 at 452 nm. Beer's law was obeyed in the concentration range 0.01-0.6 ?g mL-1 Pd(II)-HBMS. Relative standard deviation for eleven replicate determinations of 0.001 ?g mL-1 Pd(II)-HBMS was 2.8%. In the original sample detection limit was 0.1 ?g L-1. The proposed method was applied to the determination of trace palladium in automobile exhaust gas converter catalysts with good result. (authors)

2008-01-01

163

Solid phase extraction of iron and lead in environmental matrices on amberlite xad-1180/pv  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english A solid phase extraction procedure using Amberlite XAD-1180/Pyrocatechol violet (PV) chelating resin for the determination of iron and lead ions in various environmental samples was established. The procedure is based on the sorption of lead(II) and iron(III) ions onto the resin at pH 9, followed by elution with 1 mol/L HNO3 and determination by flame atomic absorption spectrometry. The influence of alkaline, earth alkaline and some transition metals, as interferents, are (more) discussed. The recoveries for the spiked analytes were greater than 95%. The detection limits for lead and iron by FAAS were 0.37 µg/L and 0.20 µg/L, respectively. Validation of the method described here was performed by using three certified reference materials (SRM 1515 Apple Leaves, SRM 2711 Montana Soil and NRCC-SLRS-4 Riverine Water). The procedure was successfully applied to natural waters and human hair.

Soylak, Mustafa; Tuzen, Mustafa; Narin, Ibrahim

2006-04-01

164

Selective determination of acidic pharmaceuticals in wastewater using molecularly imprinted solid-phase extraction.  

Science.gov (United States)

The determination of acidic pharmaceuticals, such as non-steroidal anti-inflammatory drugs NSAIDs and clofibric acid (metabolite of clofibrate), at low ngL(-1) levels in wastewater requires highly selective and sensitive analytical procedures. The removal of matrix components during sample preparation results in significant benefits towards reducing the matrix effects during LC-MS analysis. Therefore this work describes a simple method to enrich and clean up NSAIDs and clofibric acid from sewage water using molecularly imprinted solid-phase extraction (MISPE). Final analysis was performed by liquid chromatography-tandem mass spectrometry. The performance of this method has been evaluated in fortified tap and sewage water in terms of recovery, precision, linearity, and method quantification limit. Recovery for all compounds ranged in all matrices between 84 and 116% with intra-day R.S.D. values below 11.5%. Matrix effect evaluation demonstrated that even complex sample matrixes, such as pond or sewage water did not showed significant ion suppression/enhancement compared to tap water. The performance of the method was further emphasized by the study of pond water, which receives treated water from a sewage treatment plant in south Sweden. Raw sewage and treated water were also tested. In those samples, all acidic pharmaceuticals were detected in concentration above method quantification limits ranging from 5.1 to 5153.0ngL(-1). PMID:18790115

Zorita, Saioa; Boyd, Brian; Jönsson, Stig; Yilmaz, Ecevit; Svensson, Carin; Mathiasson, Lennart; Bergström, Staffan

2008-08-09

165

Determination of phenols in landfill leachate-contaminated groundwaters by solid-phase extraction  

DEFF Research Database (Denmark)

A solid-phase extraction method for phenols in landfill leachates was developed and optimized in order to solve the expected and observed problems associated with an anaerobic matrix containing high concentrations of salts and organic matter. Isolute ENV1 cartridges exhibited the best retention of phenols of the four sorbents examined, and was the only cartridge which a 1 L leachate sample could pass through. With the other cartridges, clogging made this impossible. The final method, which included 27 different phenols, gave detection limits of ,0.1 mg/L (drinking water concentration limit for pesticides) for most phenols (25), and for 12 phenols ,0.01 mg/ L. Recovery rates (determined for four concentrations in the range 1–25 mg/ L, two replicates of each) were in the range 79–104% (SD 1–12%), except for phenol (2661.3%) and 2-methoxyphenol (6264.2%). Up to 12 different phenols could be identified in leachates from three Danish landfills, ranging in concentration from 0.01 to 29 mg/ L, which is at the lower end of the concentration range usually found for phenols in landfill leachates (sub-mg/L to mg/L). ? 2002 Elsevier Science B.V. All rights reserved.

Ask Reitzel, Lotte; Ledin, Anna

2002-01-01

166

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

UK PubMed Central (United Kingdom)

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.

Morita E; Nakamura E

2011-01-01

167

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

UK PubMed Central (United Kingdom)

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.

Soylak M; Unsal YE; Yilmaz E; Tuzen M

2011-08-01

168

Microchip emitter for solid-phase extraction-gradient elution-mass spectrometry.  

Science.gov (United States)

A microchip electrospray emitter with a magnetic bead trap has been designed for solid-phase extraction-gradient elution-mass spectrometry (SPE-GEMS). The goal of this method is the detection of analytes at low concentrations and it is here demonstrated using reverse phase coated magnetic beads (Mbs) for the preconcentration and detection of the peptides. The sample is passed through the chip, and the peptides are retained and enriched in the trap. After washing, the peptides are released sequentially by stepwise gradient elution and electrosprayed for mass spectrometry analysis. This approach allows effective sample desalting, enrichment, sequential elution, and MS detection without the introduction of an additional separation step after SPE. Efficient preconcentration of model peptides by SPE and sequential release and analysis of peptides by GEMS were demonstrated for diluted sample solutions within the range of 1 ?M to 10 nM. Fortified human blood serum, protein digest and fractions collected after protein digest OFFGEL separation were analyzed by SPE-GEMS allowing the detection of low abundance peptides usually not observed by direct mass spectrometry analysis. A mathematical model for gradient elution is proposed. PMID:23730778

Gasilova, Natalia; Qiao, Liang; Momotenko, Dmitry; Pourhaghighi, Mohammad Reza; Girault, Hubert H

2013-06-18

169

Determination of Cotinine by LC-MS-MS with Automated Solid-Phase Extraction.  

UK PubMed Central (United Kingdom)

Cotinine is the primary metabolite of nicotine and the preferred biomarker for assessing cigarette smoke exposure. Several liquid chromatography-tandem mass spectrometry (LC-MS-MS) methods have been described for measuring cotinine in biological fluids. Sample preparation typically involves manual solvent evaporation and reconstitution steps. This study describes a novel LC-MS-MS method for the quantification of cotinine by using electrospray ionization with multiple reaction monitoring and cotinine-d3 as internal standard, coupled with an automated solid-phase extraction (SPE) procedure. The assay was linear over the analytical range of 0.5-1,000 ng/mL. The limits of detection and quantification were 0.13 and 0.20 ng/mL, respectively. Intra-assay and inter-assay imprecision of cotinine in all samples was <5 and <10% (coefficient of variation), respectively. The analytical recovery of cotinine spiked into plasma was >95-100%. Matrix effects in serum and plasma were <10%.A rapid, sensitive and specific LC-MS-MS method was developed and validated for the determination of cotinine in human plasma, using a straightforward automated SPE protocol. The application of this method to an epidemiological study has demonstrated its utility for batch analyses of a large sample set (>500 samples).

Dunlop AJ; Clunie I; Stephen DW; Allison JJ

2013-04-01

170

Measurement of associations of pharmaceuticals with dissolved humic substances using solid phase extraction.  

UK PubMed Central (United Kingdom)

An innovative method was developed to determine association of carbadox, lincomycin and tetracycline with dissolved humic acids using solid phase extraction (SPE). Dissolved organic matter (DOM) and DOM-bound pharmaceuticals passed through the SPE cartridge while the cartridge retained freely dissolved pharmaceuticals from water. This method was validated by comparison with the results measured using the common equilibrium dialysis technique. For the SPE method pharmaceutical interaction with DOM required ?30h to approach the equilibration, whereas 50-120h was needed for the equilibrium dialysis technique. The uneven distributions of freely membrane-penetrating pharmaceuticals and protons inside vs. outside of the dialysis cell due to the Donnan effect resulted in overestimates of pharmaceutical affinity with DOM for the equilibrium dialysis method. The SPE technique eliminates the Donnan effect, and demonstrates itself as a more efficient, less laborious and more accurate method. The measured binding coefficients with DOM followed the order of carbadox

Ding Y; Teppen BJ; Boyd SA; Li H

2013-04-01

171

Solid phase extractive preconcentration of uranium(VI) onto diarylazobisphenol modified activated carbon.  

Science.gov (United States)

Diarylazobisphenol (DAB) 1 and diarylazobisphenol modified carbon 2 were synthesized and characterised. The latter has been used for solid phase extractive preconcentration and separation of trace amounts of uranium(VI) from other inorganics. In this, a column mode preconcentration of uranium(VI) was carried out in the pH range 4.0-5.0, eluted with 1.0moll(-1) HCl and determined by an Arsenazo III spectrophotometric procedure. Calibration graphs were rectilinear over the uranium(VI) concentrations in the range 5-200mugl(-1). Five replicate determinations of 25mug of uranium(VI) present in 1l solution gave a mean absorbance of 0.032 with a relative standard deviation of 2.52%. The detection limit corresponding to three times the standard deviation of the blank was found to be 5mugl(-1). The accuracy of the developed preconcentration method in conjunction with the Arsenazo III procedure was tested by analysing MESS-3, a marine sediment certified reference material. Further, the above procedure has been successfully employed for analysis of uranium(VI) in soil and sediment samples. PMID:18969421

Starvin, A M; Rao, T Prasada

2004-05-28

172

Solid phase extractive preconcentration of uranium(VI) onto diarylazobisphenol modified activated carbon.  

UK PubMed Central (United Kingdom)

Diarylazobisphenol (DAB) 1 and diarylazobisphenol modified carbon 2 were synthesized and characterised. The latter has been used for solid phase extractive preconcentration and separation of trace amounts of uranium(VI) from other inorganics. In this, a column mode preconcentration of uranium(VI) was carried out in the pH range 4.0-5.0, eluted with 1.0moll(-1) HCl and determined by an Arsenazo III spectrophotometric procedure. Calibration graphs were rectilinear over the uranium(VI) concentrations in the range 5-200mugl(-1). Five replicate determinations of 25mug of uranium(VI) present in 1l solution gave a mean absorbance of 0.032 with a relative standard deviation of 2.52%. The detection limit corresponding to three times the standard deviation of the blank was found to be 5mugl(-1). The accuracy of the developed preconcentration method in conjunction with the Arsenazo III procedure was tested by analysing MESS-3, a marine sediment certified reference material. Further, the above procedure has been successfully employed for analysis of uranium(VI) in soil and sediment samples.

Starvin AM; Rao TP

2004-05-01

173

Solid-phase extraction and LC-MS analysis of pyrrolizidine alkaloids in honeys.  

Science.gov (United States)

Strong-cation-exchange, solid-phase extraction of pyrrolizidine alkaloids and their N-oxides from honey samples was followed by reduction of the N-oxides and subsequent analysis of total pyrrolizidine alkaloids using high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry. A limited survey of 63 preprocessing samples of honey, purposefully biased toward honeys attributed to floral sources known to produce pyrrolizidine alkaloids, demonstrated levels of pyrrolizidine alkaloids up to approximately 2000 parts per billion (ppb) in a sample attributed to Echium plantagineum. Up to 800 ppb pyrrolizidine alkaloids was detected in some honeys not attributed by the collector to any pyrrolizidine alkaloid-producing floral source. No pyrrolizidine alkaloids were detected in approximately 30% of the samples in this limited study, while some honeys showed the copresence of pyrrolizidine alkaloids from multiple floral sources such as E. plantagineum and Heliotropium europaeum. In addition, retail samples of blended honeys (with no labeling to suggest that pyrrolizidine alkaloid-producing floral sources were used in the blends) have been shown to contain up to approximately 250 ppb pyrrolizidine alkaloids. PMID:15479038

Beales, Kerrie A; Betteridge, Keith; Colegate, Steven M; Edgar, John A

2004-10-20

174

COMPARING THE SOLID PHASE AND SALINE EXTRACT MICROTOX(R) ASSAYS FOR TWO PAH CONTAMINATED SOILS  

Science.gov (United States)

The performance of remedial treatments is typically evaluated by measuring the concentration of specific chemicals. By adding toxicity bioassays to treatment evaluations, a fuller understanding of treatment performance is obtained. The solid phase Microtox assay is one potenti...

175

Core-Shell Diamond as a Support for Solid-Phase Extraction and High-Performance Liquid Chromatography  

Energy Technology Data Exchange (ETDEWEB)

We report the formation of core-shell diamond particles for solid phase extraction (SPE) and high performance liquid chromatography (HPLC) made by layer-by-layer (LbL) deposition. Their synthesis begins with the amine functionalization of microdiamond by its immersion in an aqueous solution of a primary amine-containing polymer (polyallylamine (PAAm)). The amine-terminated microdiamond is then immersed in an aqueous suspension of nanodiamond, which leads to adsorption of the nanodiamond. Alternating (self-limiting) immersions in the solutions of the amine-containing polymer and the suspension of nanodiamond are continued until the desired number of nanodiamond layers is formed around the microdiamond. Finally, the core-shell particles are cross-linked with 1,2,5,6-diepoxycyclooctane or reacted with 1,2-epoxyoctadecane. Layer-by-layer deposition of PAAm and nanodiamond is also studied on planar Si/SiO2 surfaces, which were characterized by SEM, Rutherford backscattering spectrometry (RBS) and nuclear reaction analysis (NRA). Core-shell particles are characterized by diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), environmental scanning electron microscopy (ESEM), and Brunauer Emmett Teller (BET) surface area and pore size measurements. Larger (ca. 50 ?m) core-shell diamond particles have much higher surface areas, and analyte loading capacities in SPE than nonporous solid diamond particles. Smaller (ca. 3 ?m), normal and reversed phase, core-shell diamond particles have been used for HPLC, with 36,300 plates per meter for mesitylene in a separation of benzene and alkyl benzenes on a C18 adsorbent, and 54,800 plates per meter for diazinon in a similar separation of two pesticides.

Saini, Gaurav; Jensen, David S.; Wiest, Landon A.; Vail, Michael A.; Dadson, Andrew; Lee, Milton L.; Shutthanandan, V.; Linford, Matthew R.

2010-06-01

176

Membrane solid-phase extraction: Field application for isolation of polycyclic aromatic hydrocarbons from water samples  

International Nuclear Information System (INIS)

Solid-phase extraction (SPE) membranes (M-SPE) were used to isolate microgram-per-liter to nanogram-per-liter quantities of polycyclic aromatic hydrocarbons (PAH) in 4- to 8-liter ground-water samples from a crude-oil-contaminated ground-water site near Bemidji, Minnesota. The M-SPE method was evaluated (1) under laboratory conditions using reagent water fortified with individual PAH at 1.23 micrograms per liter, and (2) at the Bemidji site. At the site, ground-water samples were processed and PAH isolated using a M-SPE system connected directly to the well pump. Following sample isolation, all M-SPE samples were extracted using dichloromethane and analyzed by gas chromatography-mass spectrometry with selected-ion monitoring. Operationally, the M-SPE method provided a simple means to isolate PAH on site at the wellhead, particularly for anoxic water samples. Acceptable recoveries, ranging from 56 to over 100 percent, were observed for lower molecular weight PAH (naphthalene to pyrene) using the M-SPE method. Recoveries using M-SPE were somewhat lower, but reproducible, for higher molecular weight PAH (chrysene to benzo[ghi]perylene), ranging from 18 to 56 percent. M-SPE provides the capability to collect and field isolate PAH from a sufficiently large number of samples to identify environmental chemical processes occurring at individual compound concentrations of 50 to 1,200 nanograms per liter. Using M-SPE, the potential for facilitated transport of PAH by in situ-derived dissolved organic carbon (DOC) was evaluated at the site. Plots comparing DOC and PAH concentrations indicate that PAH concentrations increase exponentially with linear increases in DOC concentrations

1995-01-01

177

Membrane solid-phase extraction: Field application for isolation of polycyclic aromatic hydrocarbons from water samples  

Energy Technology Data Exchange (ETDEWEB)

Solid-phase extraction (SPE) membranes (M-SPE) were used to isolate microgram-per-liter to nanogram-per-liter quantities of polycyclic aromatic hydrocarbons (PAH) in 4- to 8-liter ground-water samples from a crude-oil-contaminated ground-water site near Bemidji, Minnesota. The M-SPE method was evaluated (1) under laboratory conditions using reagent water fortified with individual PAH at 1.23 micrograms per liter, and (2) at the Bemidji site. At the site, ground-water samples were processed and PAH isolated using a M-SPE system connected directly to the well pump. Following sample isolation, all M-SPE samples were extracted using dichloromethane and analyzed by gas chromatography-mass spectrometry with selected-ion monitoring. Operationally, the M-SPE method provided a simple means to isolate PAH on site at the wellhead, particularly for anoxic water samples. Acceptable recoveries, ranging from 56 to over 100 percent, were observed for lower molecular weight PAH (naphthalene to pyrene) using the M-SPE method. Recoveries using M-SPE were somewhat lower, but reproducible, for higher molecular weight PAH (chrysene to benzo[ghi]perylene), ranging from 18 to 56 percent. M-SPE provides the capability to collect and field isolate PAH from a sufficiently large number of samples to identify environmental chemical processes occurring at individual compound concentrations of 50 to 1,200 nanograms per liter. Using M-SPE, the potential for facilitated transport of PAH by in situ-derived dissolved organic carbon (DOC) was evaluated at the site. Plots comparing DOC and PAH concentrations indicate that PAH concentrations increase exponentially with linear increases in DOC concentrations.

Furlong, E.T.; Koleis, J.C.; Gates, P.M. [Geological Survey, Arvada, CO (United States)

1995-12-31

178

Liquid chromatographic determination of amoxicillin concentrations in bovine plasma by using a tandem solid-phase extraction method.  

UK PubMed Central (United Kingdom)

We report a means of determining amoxicillin in bovine plasma by liquid chromatography with UV detection at 235 nm. Purification and concentration of extracts were accomplished by a tandem solid-phase extraction procedure with two reversed-phase columns. Separation of amoxicillin from interferences was improved by the incorporation of a crown ether in the solvent systems used both for the solid-phase extraction and the final high-pressure liquid chromatography. Cefadroxil was added as an internal standard. The average recovery of amoxicillin from plasma (n = 23) was 78.2 +/- 3.0%, and the within-run and between-run coefficients of variation ranged from 1.8 to 7.0%. The detection limit was estimated at 0.1 microgram/ml. This method was used to determine amoxicillin in bovine plasma after intramuscular administration of the drug.

Nelis HJ; Vandenbranden J; De Kruif A; De Leenheer AP

1992-09-01

179

The Speciation Analysis of Radioactive Iodine in Aqueous Samples Using a New Derivatisation-Solid Phase Extraction Method  

International Nuclear Information System (INIS)

Full text: A new derivatization-solid phase extraction (DSPE) method was developed for the identification of radioactive iodine species, especially iodate (IO3 -) and iodide (I-), in aqueous samples. It was based on the conversion of iodine species to 4-iodo-N, N-dimethylaniline (IDMA) which was then extracted from the aqueous sample by using solid phase extraction. DSPE methods could be adapted to collect individual 129I species as radioactive IDMA which could be then measured by liquid scintillation counting (LSC). The mean recoveries from determining 129I- (?9.2 Bq g-1) and 129IO3 - (?0.52 Bq g-1) in water were 96.5±2.6 % and 94.6±0.8 %, respectively. These adapted methods would be applied for the speciation analysis of radioactive iodine in environmental samples

2011-01-01

180

Ultra-high performance liquid chromatography/tandem mass spectrometry determination of feminizing chemicals in river water, sediment and tissue pretreated using disk-type solid-phase extraction and matrix solid-phase dispersion.  

UK PubMed Central (United Kingdom)

This study developed and validated a method of measuring the feminizing chemicals 4-tert-octylphenol, 4-nonylphenol, nonylphenol monoethoxycarboxylate (NP(1)EC), nonylphenol monoethoxylate (NP(1)EO), nonylphenol diethoxylate (NP(2)EO), estrone, 17?-estradiol, estriol, 17?-ethinyl estradiol and bisphenol A in river water, sediment, and tissue using ultra-high performance liquid chromatography/tandem mass spectrometry (UHPLC/MS/MS) and isotope-dilution techniques. Water samples were pretreated using disk-type automated solid-phase extraction (SPE). Solid samples of sediment, fish, and clams were treated with matrix solid-phase dispersion (MSPD) using C(8) adsorbent. Eluents were directly passed following alumina cartridges for cleanup. The signal intensity of analytes on electrospray ionization (ESI) was compared with that of atmospheric pressure photoionization (APPI). The analytes were separated on a UHPLC C(18) column with aqueous 10-mM ammonium acetate for NPEOs and aqueous 10-mM N-methylmorpholine for the other compounds. On-line cleanup was evaluated using two-dimensional liquid chromatography (2-D LC). ESI could provide satisfactory response for all of the analytes. Though APPI did not offer suitable response for NP(1)EO, NP(2)EO and NP(1)EC, it provided better signal intensities for the steroid estrogens (1.0-2.4 times) and the phenols (3.2-4.4 times) than ESI. UHPLC shortened chromatographic time to less than 10 min. Disk-type automated SPE and MSPD dramatically increased the throughput of sample preparation. The extraction efficiency on surface water samples ranged from 10% to 91%. The extraction efficiency of MSPD on sediment, fish, and clams was 51-101%, 36-109%, and 30-111%, respectively. Acidic alumina cleanup was essential for the analysis of the tissue sample, and reduced matrix effects better than 2-D LC on-line cleanup. The limits of detection (LODs) in water ranged from 0.81 ng/L to 89.9 ng/L. The LODs in sediment and tissue ranged from tens of pg/g wet weight to only a few ng/g wet weight. This method proved to be accurate and reproducible, as both quantitative biases and relative deviations remained smaller than 20% at three spiked levels.

Chen WL; Wang GS; Gwo JC; Chen CY

2012-01-01

 
 
 
 
181

Ultra-high performance liquid chromatography/tandem mass spectrometry determination of feminizing chemicals in river water, sediment and tissue pretreated using disk-type solid-phase extraction and matrix solid-phase dispersion.  

Science.gov (United States)

This study developed and validated a method of measuring the feminizing chemicals 4-tert-octylphenol, 4-nonylphenol, nonylphenol monoethoxycarboxylate (NP(1)EC), nonylphenol monoethoxylate (NP(1)EO), nonylphenol diethoxylate (NP(2)EO), estrone, 17?-estradiol, estriol, 17?-ethinyl estradiol and bisphenol A in river water, sediment, and tissue using ultra-high performance liquid chromatography/tandem mass spectrometry (UHPLC/MS/MS) and isotope-dilution techniques. Water samples were pretreated using disk-type automated solid-phase extraction (SPE). Solid samples of sediment, fish, and clams were treated with matrix solid-phase dispersion (MSPD) using C(8) adsorbent. Eluents were directly passed following alumina cartridges for cleanup. The signal intensity of analytes on electrospray ionization (ESI) was compared with that of atmospheric pressure photoionization (APPI). The analytes were separated on a UHPLC C(18) column with aqueous 10-mM ammonium acetate for NPEOs and aqueous 10-mM N-methylmorpholine for the other compounds. On-line cleanup was evaluated using two-dimensional liquid chromatography (2-D LC). ESI could provide satisfactory response for all of the analytes. Though APPI did not offer suitable response for NP(1)EO, NP(2)EO and NP(1)EC, it provided better signal intensities for the steroid estrogens (1.0-2.4 times) and the phenols (3.2-4.4 times) than ESI. UHPLC shortened chromatographic time to less than 10 min. Disk-type automated SPE and MSPD dramatically increased the throughput of sample preparation. The extraction efficiency on surface water samples ranged from 10% to 91%. The extraction efficiency of MSPD on sediment, fish, and clams was 51-101%, 36-109%, and 30-111%, respectively. Acidic alumina cleanup was essential for the analysis of the tissue sample, and reduced matrix effects better than 2-D LC on-line cleanup. The limits of detection (LODs) in water ranged from 0.81 ng/L to 89.9 ng/L. The LODs in sediment and tissue ranged from tens of pg/g wet weight to only a few ng/g wet weight. This method proved to be accurate and reproducible, as both quantitative biases and relative deviations remained smaller than 20% at three spiked levels. PMID:22284486

Chen, Wen-Ling; Wang, Gen-Shuh; Gwo, Jin-Chywan; Chen, Chia-Yang

2011-12-14

182

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

UK PubMed Central (United Kingdom)

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.

Wan Ibrahim WA; Veloo KV; Sanagi MM

2012-03-01

183

Selective solid-phase extraction of a triterpene acid from a plant extract by molecularly imprinted polymer.  

Science.gov (United States)

A molecularly imprinted polymer (MIP) has been prepared by a thermal polymerisation method using methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linking agent, chloroform as porogenic solvent and an oleanane triterpene compound (18-beta-glycyrrhetinic acid) as imprinted molecule (template). Equilibrium ligand binding experiments were done to assess the performance of the MIP relative to non-imprinted polymer (NIP). After optimisation of SPE protocol (CHCl3 as washing solvent and MeOH as elution solvent), successful imprinting was confirmed by comparison of the recoveries between NIP (5%) and MIP (97%) cartridges. The binding capacity of the MIP for 18-beta-glycyrrhetinic acid was determined to be 0.94 mg g(-1). Four structurally related oleanane triterpenes (18-alpha-glycyrrhetinic acid, oleanolic acid, echinocystic acid, erythrodiol) were selected to assess the MIP selectivity. Experimental data illustrated the influence of functional groups on the triterpene skeleton. The MIP was applied to the solid-phase extraction of triterpenoids from a plant extract prior HPLC analysis. However, CHCl3 was replaced by ACN during the washing step in order to suppress non-specific interactions due to polar matrix components. A selective extraction of 18-beta-glycyrrhetinic acid from hydrolyzed extract of liquorice roots was achieved with a good extraction yield (98%). PMID:18371889

Claude, Bérengère; Morin, Philippe; Lafosse, Michel; Belmont, Anne-Sophie; Haupt, Karsten

2007-11-21

184

Capillary electrophoresis for analyzing pesticides in fruits and vegetables using solid-phase extraction and stir-bar sorptive extraction.  

UK PubMed Central (United Kingdom)

Two procedures based on solid-phase extraction (SPE) and stir-bar sorptive extraction (SBSE) in combination with micellar electrokinetic chromatography (MEKC)--diode array detection (DAD) were compared for the simultaneous extraction of acrinathrin, bitertanol, cyproconazole, fludioxonil, flutriafol, myclobutanil, pyriproxyfen, and tebuconazole in lettuce, tomato, grape, and strawberry. Selectivity and resolution of the MEKC procedure were studied changing the pH and the molarity of the buffer, the type and the concentration of surfactant, and the methanol content in the mobile phase. A buffer consisting of 6 mM sodium tetraborate decahydrate with 75 mM of cholic acid sodium solution (pH 9.2) gave the best results. Linearity, extraction efficiencies and limits of quantitation (LOQs) of both extraction methods were compared. The recoveries obtained by SPE ranged from 40 to 106% with relative standard deviations (R.S.D.s) from 10 to 19% whereas by the SBSE method, the recoveries were 12-47% and the R.S.D.s 3-17%. The LOQs were much better by SPE (0.2-0.5 mg kg(-1) depending on the processed sample amount) than those obtained by SBSE (1 mg kg(-1) for each compound). Advantages and disadvantages of both procedures are also discussed. As SPE is more robust, rapid, and sensitive than SBSE, its application in combination with MEKC is recommended because provided LOQs below the MRLs established, which is not always attained by SBSE.

Juan-García A; Picó Y; Font G

2005-05-01

185

Capillary electrophoresis for analyzing pesticides in fruits and vegetables using solid-phase extraction and stir-bar sorptive extraction.  

Science.gov (United States)

Two procedures based on solid-phase extraction (SPE) and stir-bar sorptive extraction (SBSE) in combination with micellar electrokinetic chromatography (MEKC)--diode array detection (DAD) were compared for the simultaneous extraction of acrinathrin, bitertanol, cyproconazole, fludioxonil, flutriafol, myclobutanil, pyriproxyfen, and tebuconazole in lettuce, tomato, grape, and strawberry. Selectivity and resolution of the MEKC procedure were studied changing the pH and the molarity of the buffer, the type and the concentration of surfactant, and the methanol content in the mobile phase. A buffer consisting of 6 mM sodium tetraborate decahydrate with 75 mM of cholic acid sodium solution (pH 9.2) gave the best results. Linearity, extraction efficiencies and limits of quantitation (LOQs) of both extraction methods were compared. The recoveries obtained by SPE ranged from 40 to 106% with relative standard deviations (R.S.D.s) from 10 to 19% whereas by the SBSE method, the recoveries were 12-47% and the R.S.D.s 3-17%. The LOQs were much better by SPE (0.2-0.5 mg kg(-1) depending on the processed sample amount) than those obtained by SBSE (1 mg kg(-1) for each compound). Advantages and disadvantages of both procedures are also discussed. As SPE is more robust, rapid, and sensitive than SBSE, its application in combination with MEKC is recommended because provided LOQs below the MRLs established, which is not always attained by SBSE. PMID:15909524

Juan-García, Ana; Picó, Yolanda; Font, Guillermina

2005-05-01

186

Comparison of solvent extraction and solid-phase extraction for the determination of organochlorine pesticide residues in water.  

UK PubMed Central (United Kingdom)

Solid-phase extraction (SPE) of organochlorine pesticide residues from environmental water samples was evaluated using octadecyl (C18)-bonded porous silica. The efficiency of SPE of these pesticide residues from reagent water samples at 1-5 micrograms dm-3 levels was compared with those obtained by solvent extraction with hexane and Freon TF (trichlorotrifluoroethane). Average recoveries exceeding 80% for these organochlorine pesticides were obtained via the SPE method using small cartridges containing 100 mg of 40 microns C18-bonded porous silica. The average recovery by solvent extraction with hexane and Freon TF exceeded 90% in both instances. It was concluded that the recoveries and precision for the SPE of organochlorine pesticides were poorer than those for the solvent extraction method. Organochlorine pesticide residue levels in environmental water samples from two major rivers flowing through predominantly rice-growing areas were monitored by gas chromatography using the solvent extraction method with hexane. Exceptionally high levels of organochlorine pesticide residues such as BHC, DDT, heptachlor, endosulfan and dieldrin were found in these water samples.

Tan GH

1992-07-01

187

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

Directory of Open Access Journals (Sweden)

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?; Vojislava Bursi?; Slavica Vukovi?

2007-01-01

188

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

UK PubMed Central (United Kingdom)

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.

Chung WH; Tzing SH; Ding WH

2013-09-01

189

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

2013-07-24

190

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

International Nuclear Information System (INIS)

[en] 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)

2002-07-03

191

Determination of trace total inorganic arsenic by hydride generation atomic fluorescence spectrometry after solid phase extraction-preconcentration on aluminium hydroxide gel  

International Nuclear Information System (INIS)

[en] We describe a simple, effective, inexpensive and rapid method for the determination of trace amounts of total inorganic arsenic in water samples by means of a modified solid phase preconcentration procedure using an aluminium hydroxide gel sorbent and hydride generation atomic fluorescence spectrometry (HGAFS). This method avoids the traditional extraction procedures that are time- and solvent-consuming. The effects of quantity of adsorbent, solution pH, adsorption time and potentially interfering ions were studied. Under the optimal conditions, the detection limit is 3 ng.L-1, and the enrichment factor is 167. The calibration plot is linear in the range from 0.05 to 10 ?g.L-1, with a correlation coefficient of 0.9992. The relative standard deviation (RSD) was less than 6.1 % (n = 5) and recoveries in spiked environmental water were >100 %. The method was successfully applied to the determination of total inorganic arsenic in natural water samples. (author)

2013-01-01

192

Xylenol orange adsorbed on silica surface as a solid phase reagent for lead determination using diffuse reflectance spectroscopy.  

Science.gov (United States)

The solid-phase reagents on the base of xylenol orange and its complex with Fe(III) immobilized on silica surface were obtained. The interaction of Pb(II) with developed reagents was studied. The conditions of quantitative recovery of Pb(II) from diluted solutions, such as acidity of aqueous phase, the amount of the sorbent, the volume of solutions and the time of equilibrium reaching, were examined. The tolerance limits of metal ions in the sorption of Pb(II) at pH 4.5-5.5 are reported. The capabilities of immobilized xylenol orange for Pb(II) pre-concentration prior to its diffusion reflectance spectroscopic detection was evaluated. The detection limit was 2 mug l(-1). The developed method was applied to Pb(II) determination in natural water and foodstuffs. PMID:18968817

Zaporozhets, O A; Tsyukalo, L Ye

2002-11-12

193

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

194

Optimization of in-line fritless solid-phase extraction for capillary electrophoresis-mass spectrometry.  

UK PubMed Central (United Kingdom)

In this study, in-line frit-free solid-phase extraction (SPE) has been studied for the preconcentration of analytes prior to analysis by capillary electrophoresis-mass spectrometry (CE-MS). The mixed-mode sorbent Oasis HLB was selected for the trapping of compounds of different polarity. Using 2-ethylidene-1,5-dimethyl-3,3-diphenylpirrolidine (EDDP), dihydrocodeine and codeine as test compounds, SPE parameters such as the pH of the sample and composition of the washing and elution solvent were optimized. Trapping of the analytes was optimal at pH 8.0 or higher. For efficient elution of the SPE micro column, 85% of methanol in water with 2% (v/v) acetic acid was used, which also prevented current break down in subsequent CE analysis. CE resolution of the test compounds was highest for background electrolytes (BGEs) with a pH above 8. For optimal analysis, samples were 1:1 diluted with carbonate buffer (1M, pH 8.0) prior to analysis, BGE was 60mM ammonium acetate buffer (pH 10.0), and the injected sample volume was 60 ?l (i.e., 30 capillary volumes). Good recoveries were found: 101% for EDDP, 88% for codeine and 90% for dihydrocodeine. Intraday RSDs for migration time and peak areas were below 0.56% and 15%, respectively. Peak widths at half height obtained with SPE-CE-MS were 12s for EDDP, 3.7s for dihydrocodeine and 7.4s for codeine, and were comparable to those for CE-MS. LODs were 0.22 pg/ml for EDDP, 2.1 pg/ml for dihydrocodeine and 24 pg/ml for codeine. It is concluded that the applied fritless in-line preconcentration construct proved to be highly useful for improving the sensitivity of CE while maintaining separation.

Tak YH; Toraño JS; Somsen GW; de Jong GJ

2012-12-01

195

An integrated solid-phase extraction system for sub-picomolar detection.  

UK PubMed Central (United Kingdom)

A microchip structure etched on a glass substrate for packed column solid-phase extraction (SPE) and capillary electrochromatography (CEC) is described. A 200 microm long, octadecylsilane (ODS) packed column was secured using two different approaches: solvent lock or polymer entrapment. The former method was utilized for SPE while the latter approach was applied for CEC. In SPE, the ODS packed chamber gave a detection limit of 70 fM for a nonpolar BODIPY (493/503) dye when concentrated for 3 min at an electroosmotic flow rate of 4.14 nL/min, compared to 30 pM for this detector without the SPE step. SPE beds showed reproducible, linear calibration curves (R(2) = 0.9989) between 1 and 100 pM BODIPY at fixed preconcentration times. Breakthrough curves for the 330 pL (ODS-packed) bed indicated a capacity for BODIPY dye of 8.1 x 10(-14) mmol, or 0.25 mmol dye per liter of bed. The ODS-chamber could also be used to analyze dilute amino acid and peptide solutions. In the CEC format, two neutral dyes (BODIPY and acridine orange) were baseline-separated in an isocratic run with a theoretical plate count of 84 (420 000 plates/m) and a reduced plate height of about 1. A labeled peptide was also analyzed by CEC, using the acidic eluent (84% acetonitrile, and 26% aqueous trifluoroacetic acid (0.05%)) preferred for peptide separations on ODS-coated silica particles.

Jemere AB; Oleschuk RD; Ouchen F; Fajuyigbe F; Harrison DJ

2002-10-01

196

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

Science.gov (United States)

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. PMID:20536156

Mysling, Simon; Palmisano, Giuseppe; Højrup, Peter; Thaysen-Andersen, Morten

2010-07-01

197

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

UK PubMed Central (United Kingdom)

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 S; Palmisano G; Højrup P; Thaysen-Andersen M

2010-07-01

198

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.

2010-01-01

199

Determination of herbicides by solid phase extraction gas chromatography-mass spectrometry in drinking waters.  

UK PubMed Central (United Kingdom)

A solid 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, styrene-divinylbenzene, phenyl, graphitic carbon). The type of conditioning and elution solvent, its volume, and the sample flow rate have been considered as variables affecting the recovery yields of the herbicides. The optimized experimental conditions are C18 phase conditioned with 3 mL acetone, loaded with 1L water sample at 5 mL min(-1), and eluted with 3 mL acetone. Good recoveries (included between 79% and 99%) and R.S.D. (included between 2% and 12%) have been obtained for all analytes, except for deethylatrazine whose recovery was 46+/-7%. The recovery of deethylatrazine increases up to 94+/-17% if a non-porous graphitic carbon is coupled to the C18 phase, keeping the other parameters constant as optimized. The optimized method has been successfully checked for the identification and quantitation of the selected herbicides in raw and drinking water samples, with quantitation limits as low as 0.01 microg L(-1), fully in agreement with the current legislation. The method is easily routinable. After development, the method is currently routinely applied for the analysis of herbicides in waters and, up today, more than one thousand samples have been analysed at the "Laboratorio della Società Metropolitana Acque di Torino" (Laboratory of the Municipal Waterworks of Turin) in charge of the control of drinking water quality in Torino.

Bruzzoniti MC; Sarzanini C; Costantino G; Fungi M

2006-09-01

200

Determination of herbicides by solid phase extraction gas chromatography-mass spectrometry in drinking waters.  

Science.gov (United States)

A solid 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, styrene-divinylbenzene, phenyl, graphitic carbon). The type of conditioning and elution solvent, its volume, and the sample flow rate have been considered as variables affecting the recovery yields of the herbicides. The optimized experimental conditions are C18 phase conditioned with 3 mL acetone, loaded with 1L water sample at 5 mL min(-1), and eluted with 3 mL acetone. Good recoveries (included between 79% and 99%) and R.S.D. (included between 2% and 12%) have been obtained for all analytes, except for deethylatrazine whose recovery was 46+/-7%. The recovery of deethylatrazine increases up to 94+/-17% if a non-porous graphitic carbon is coupled to the C18 phase, keeping the other parameters constant as optimized. The optimized method has been successfully checked for the identification and quantitation of the selected herbicides in raw and drinking water samples, with quantitation limits as low as 0.01 microg L(-1), fully in agreement with the current legislation. The method is easily routinable. After development, the method is currently routinely applied for the analysis of herbicides in waters and, up today, more than one thousand samples have been analysed at the "Laboratorio della Società Metropolitana Acque di Torino" (Laboratory of the Municipal Waterworks of Turin) in charge of the control of drinking water quality in Torino. PMID:17723718

Bruzzoniti, M C; Sarzanini, C; Costantino, G; Fungi, M

2006-06-30

 
 
 
 
201

Chromatographic determination of drugs of abuse in vitreous humor using solid-phase extraction.  

UK PubMed Central (United Kingdom)

A simple method is presented for the simultaneous determination of morphine, 6-acetylmorphine, codeine, cocaine, benzoylecgonine, cocaethylene, methadone and 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) in vitreous humor by high-performance liquid chromatography with photodiode array detector after solid-phase extraction with Oasis® HLB cartridges and dichloromethane as eluent. The chromatographic process was carried out using an XTerra® RP8 column (250?×?4.6?mm i.d., 5?µm particle size) and a mobile phase composed of acetonitrile and pH 6.5 phosphate buffer in gradient mode. A linear response from the detector was obtained within the concentration range of 0.1-4?µg ml(-1) , with correlation coefficients higher than 0.99. The limits of detection were lower than 30?ng ml(-1) for all the drugs studied, the coefficients of variation fluctuated between 0.1 and 12.4%, and the average recoveries were higher than 78% for all the drugs except for EDDP, with a value of 66.4%. Finally, the proposed method was applied to 15 vitreous humor samples coming from individuals who had died from opiate and/or cocaine overdose, showing consumption of cocaine in 14 cases, methadone in five cases and heroin in three cases. Average concentrations of 0.30?µg ml(-1) for morphine, 0.24?µg ml(-1) for 6-acetylmorphine, 0.10?µg ml(-1) for codeine, 0.81?µg ml(-1) for cocaine, 1.26?µg ml(-1) for benzoylecgonine, 0.15?µg ml(-1) for cocaethylene, 0.11?µg ml(-1) for methadone and 0.68?µg ml(-1) for EDDP were obtained.

Fernández P; Seoane S; Vázquez C; Tabernero MJ; Carro AM; Lorenzo RA

2013-08-01

202

Effect of process conditions on the analysis of free and conjugated estrogen hormones by solid-phase extraction-gas chromatography/mass spectrometry (SPE-GC/MS).  

Science.gov (United States)

Simultaneous analysis of 11 free estrogen hormones and five conjugated estrogens in water and municipal wastewater was studied. The analytical method was developed and tested for different types of solid-phase extraction adsorbents, eluents, sample containers and storage conditions, derivatization, and matrix effects. Varian Bond Elut C-18 solid-phase extraction adsorbent cartridge was selected based on its high recoveries for both free and conjugated estrogens. Sample storage conditions, as well as selection and pretreatment of sample container materials, can affect the trace level analysis of estrogens. Silanization of glassware is observed to provide low relative standard deviation (RSD) in the analysis and less percentage loss due to contacting with sample container materials. Light exposure during the test can significantly impact the results. The derivatized samples stored at -20°C for at least 6 days showed less than 10.5% average RSD in the analysis. The recovery efficiency in clean water varies from 72% to 101% for free estrogens and 78% to 82% for conjugated estrogens. The method detection limits (MDL) for most of the compounds range from 30 to 870 ng/L using a sample volume of 200 mL. With a sample volume of 3 L, the most sensitive compound produces a MDL of 0.03 ng/L. Dilute methanol is used to wash the loaded cartridge as a cleanup step in order to remove interfering species during analysis of wastewater samples. Using the optimized analytical methods, the concentration level of free estrogens in the influent and effluent municipal wastewaters is tested. PMID:21544501

Suri, Rominder P S; Singh, Tony Sarvinder; Chimchirian, Robert F

2011-05-05

203

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

2013-04-18

204

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

UK PubMed Central (United Kingdom)

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.

Sadeghi S; Jahani M

2013-11-01

205

On-site solid-phase extraction and application to in situ preconcentration of heavy metals in surface water.  

Science.gov (United States)

An on-site solid-phase extraction, consisting of the sorption, the separation and the elution function units, was designed for in situ preconcentration of heavy metals ions. The D401 resin powder was employed as sorbent to capture Pb(2+), Cu(2+), Zn(2+), Cd(2+), Co(2+), and Ni(2+), and then they desorbed with 2 mol/L nitric acid as eluent. Under the optimized conditions, these heavy metals ions in West Lake, Taihu Lake, and Yangtze River of China were captured and then determined by ICP-OES with the recovery of 92.5% to 111.5%. The on-site solid-phase extraction achieved a quick preconcentration of heavy metals to avoid the transport and storage of a large volume water sample. It is suitable for in situ monitoring of water quality in mountains, tablelands or other remote areas. PMID:22286838

Jiao, Fang; Gao, Hong-Wen

2013-01-01

206

On-site solid-phase extraction and application to in situ preconcentration of heavy metals in surface water.  

UK PubMed Central (United Kingdom)

An on-site solid-phase extraction, consisting of the sorption, the separation and the elution function units, was designed for in situ preconcentration of heavy metals ions. The D401 resin powder was employed as sorbent to capture Pb(2+), Cu(2+), Zn(2+), Cd(2+), Co(2+), and Ni(2+), and then they desorbed with 2 mol/L nitric acid as eluent. Under the optimized conditions, these heavy metals ions in West Lake, Taihu Lake, and Yangtze River of China were captured and then determined by ICP-OES with the recovery of 92.5% to 111.5%. The on-site solid-phase extraction achieved a quick preconcentration of heavy metals to avoid the transport and storage of a large volume water sample. It is suitable for in situ monitoring of water quality in mountains, tablelands or other remote areas.

Jiao F; Gao HW

2013-01-01

207

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

2008-05-30

208

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 ...

209

Selective trace enrichment of acidic pharmaceuticals in real water and sediment samples based on solid-phase extraction using multi-templates molecularly imprinted polymers.  

UK PubMed Central (United Kingdom)

A novel multi-templates molecularly imprinted polymer (MIP), using acidic pharmaceuticals mixture (ibuprofen (IBP), naproxen (NPX), ketoprofen (KEP), diclofenac (DFC), and clofibric acid (CA)) as the template, was prepared as solid-phase extraction (SPE) material for the quantitative enrichment of acidic pharmaceuticals in environmental samples and off-line coupled with liquid chromatography-mass spectrometry (LC/MS/MS). Washing solvent was optimized in terms of kind and volume for removing the matrix constituents nonspecifically adsorbed on the MIP. When 1L of water sample spiked at 1?g/L was loaded onto the cartridge, the binding capacity of the MIP cartridge were 48.7?g/g for KEP, 60.7?g/g for NPX, 52?g/g for CA, 61.3?g/g for DFC and 60.7?g/g for IBP, respectively, which are higher than those of the commercial single template MIP in organic medium (e.g. toluene) reported in the literature. Recoveries of the five acidic pharmaceuticals extracted from 1L of real water samples such as lake water and wastewater spiked at 1?g/L were more than 95%. The recoveries of acidic pharmaceuticals extracted from 10-g sediment sample spiked at the 10ng/g level were in the range of 77.4-90.6%. To demonstrate the potential of the MIP obtained, a comparison with commercial C18 SPE cartridge was performed. Molecularly imprinted solid-phase extraction (MISPE) cartridge showed higher recoveries than commercial C18 SPE cartridge for acidic pharmaceuticals. These results showed the suitability of the MISPE method for the selective extraction of a group of structurally related compounds such as acidic pharmaceuticals.

Duan YP; Dai CM; Zhang YL; Ling-Chen

2013-01-01

210

The use of solid phase extraction method for analysis of residues of pesticides used in banana production in Costa Rica  

International Nuclear Information System (INIS)

[en] Different solid phase extraction devices were tested for the analysis of residues of eleven pesticides used in banana production in Costa Rica. The analysis was performed by using gas chromatograph equipped with NPD and ECD detectors. In general low recoveries and high variation coefficients were found for chlorothalonil, imazalil, terbufos and thiabendazole. For the other pesticides recoveries ranged between 60 and over 100%. (author)

1999-01-01

211

Combination of solid phase extraction and flame atomic absorption spectrometry for differentiated analysis of labile iron (II) and iron (III) species  

Energy Technology Data Exchange (ETDEWEB)

The labile iron(II) and iron(III) species are complexed directly in the sample solution with 1,10 phenanthroline and ferron (8-hydroxy-7-iodoquinoline-5-sulfonic acid), respectively. The complexes thus formed are mutually adsorbed and separated by solid phase extraction. The direct determination of iron(III) and iron(II) species with flame atomic absorption spectrometry (FAAS) follows the elution of the iron(III)-ferron complex adsorbed by an anion-exchange and an iron(II)-phenanthroline complex adsorbed by a non-polar RP-18 phase. In the case of indirect determination, the iron(II)-phenanthroline complex that passes through the anion-exchange phase, is measured, and the content of iron(III) is calculated by the difference of the iron(II) and the total iron content. A direct determination with this method has been applied to the iron species analysis in wine samples and the results are compared with those obtained for the determination with adsorptive stripping voltammetry (ASV) as reference method. (orig.) With 4 figs., 3 tabs.

Tawali, A.B. [Faculty of Agriculture, Hasanuddin Univ., Ujung Pandang (Indonesia); Schwedt, G. [Inst. for Inorganic and Analytical Chemistry, Technical Univ. Clausthal, Clausthal-Zellerfeld (Germany)

1997-01-01

212

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

UK PubMed Central (United Kingdom)

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.

Mohajeri SA; Hosseinzadeh H; Keyhanfar F; Aghamohammadian J

2010-08-01

213

Rapid magnetic solid phase extraction with in situ derivatization of methylmercury in seawater by Fe3O4/polyaniline nanoparticle.  

UK PubMed Central (United Kingdom)

A new Fe(3)O(4)/polyaniline nanoparticle (PANI) material has been successfully developed as magnetic solid-phase extraction sorbent in dispersion mode for the determination of methylmercury (MeHg) in aqueous samples, via quantification by gas chromatography/mass spectrometry (GC-MS). The resultant core-shell magnetic solid-phase extraction nanoparticle (MSPE-NP) sorbent was characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS) and Fourier transform-infrared (FTIR) spectroscopy. Fe(3)O(4)/PANI composites showed fibrous structure with diameters between 50 and 100 nm for fibers. The MSPE-NP process involved the dispersion of the Fe(3)O(4)/PANI nanoparticles in water samples with sonication, followed by magnetic aided retrieval of the sorbent and then, solvent (hexane) desorption of extracted MeHg for GC-MS analysis. The extraction, derivatization and adsorption conditions were optimized by selecting the appropriate extraction parameters including the amount of sorbent, extraction time, derivatizing reagent volume and extraction solvent. The calibration graph was linear in the concentration range of 0.5-300 ng mL(-1) (R(2)>0.993) with detection limit of 0.1 ng mL(-1) (n=3), while the repeatability was 4.1% (n=5). Enrichment factor was obtained as 91. Seawater sample was analyzed as real sample and good recoveries (>98%) were obtained at different spiked values.

Mehdinia A; Roohi F; Jabbari A

2011-07-01

214

Molecularly imprinted solid-phase extraction method for the high-performance liquid chromatographic analysis of fungicide pyrimethanil in wine.  

Science.gov (United States)

A method for molecularly imprinted solid-phase extraction (MISPE) of the fungicide pyrimethanil from wine samples has been investigated. The molecular imprinted polymer was obtained by iniferter-mediated grafting on porous chloromethylated polystyrene beads, using methacrylic acid as the functional monomer and ethylene glycol dimethacrylate as the cross-linker. The imprinted beads were evaluated for use as a solid-phase extraction sorbent, in order to develop the extraction protocol in aqueous standards and red wine samples. The optimised extraction protocol resulted in a reliable MISPE method suitable for HPLC analysis (stationary phase: Cromolith Performance C18 column, 100 mm x 4.6 mm; mobile phase: acetonitrile-water (3:2, v/v), flow-rate: 1.00 ml/min; detection 270 nm). It was selective for pyrimethanil and the related pyrimidinic fungicides cyprodinil and mepanipyrim, while the non-pyrimidinic fungicides benalaxyl, chlozolinate, furalaxyl, iprodione, metalaxyl, nuarimol, procymidone and vinclozolin were not extracted. Recoveries performed on a wine matrix spiked with pyrimethanil at three different concentration levels were reproducible and were in good agreement with the recoveries performed on buffer, coming out between 80 and 90% (85+/-7.0% at 0.50 microg/ml, 79+/-1.6% at 2.0 microg/ml and 87+/-5.6% at 20 microg/ml). Preconcentration and quantitative extraction of pyrimethanil from wine samples was shown to be feasible down to 0.1 microg/ml. PMID:17178127

Baggiani, C; Baravalle, P; Giraudi, G; Tozzi, C

2006-12-18

215

Solid-phase extraction of methadone enantiomers and benzodiazepines in biological fluids by two polymeric cartridges for liquid chromatographic analysis.  

UK PubMed Central (United Kingdom)

The aim of this work was to present the advantages of two polymeric cartridges (Oasis HLB from Waters and Abselut Nexus from Varian) for the solid-phase extraction of methadone enantiomers and its major metabolite, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) and of some benzodiazepines (diazepam, flunitrazepam, nitrazepam, oxazepam) in serum and urine in comparison with classical C18-bonded-silica cartridges or liquid extraction. After addition of serum or urine samples, these two cartridges were washed with a water-methanol mixture (95:5, v/v) and eluted with diethylether. After rapid evaporation, the residue was regenerated with mobile phase and injected either in a chiral column (Cyclobond I-2000 RSP) for methadone enantiomers and its metabolite or in a reversed-phase column (Symmetry Shield RP8) for benzodiazepines. The results showed that the chromatograms of blank serum and urine were cleaner than those obtained from classical solid-phase extraction or liquid extraction. The recoveries from these two polymeric cartridges were higher (95-102%) than those obtained by the two previous classical methods and the total time for extraction and solvent evaporation was also shorter (about 6-7 min). For methadone and benzodiazepine extraction, the use of acidic or alkaline buffer was not necessary.

He H; Sun C; Wang XR; Pham-Huy C; Chikhi-Chorfi N; Galons H; Thevenin M; Claude JR; Warnet JM

2005-01-01

216

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

Directory of Open Access Journals (Sweden)

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.

Béatrice Roy; Sung Vo Duy; Jean-Yves Puy; Charlotte Martin; Jérome Guitton; Charles Dumontet; Christian Périgaud; Isabelle Lefebvre-Tournier

2012-01-01

217

Determination of alternariol and alternariol methyl ether in apple juice using solid-phase extraction and high performance liquid chromatography.  

UK PubMed Central (United Kingdom)

The present work describes a new method for determination of alternariol (AOH) and alternariol methyl ether (AME) in apple juice using solid-phase extraction (SPE) columns for extraction and cleanup of samples for high-performance liquid chromatography (HPLC). Chromatograms of spiked samples show that both toxins can be easily detected without interferences, and good recoveries for AOH (82.8 +/- 7.4%) and AME (91.9 +/- 6.1%) with detection limits as low as 1.6 and 0.7 micrograms/l, respectively, were obtained.

Delgado T; Gómez-Cordovés C; Scott PM

1996-04-01

218

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

UK PubMed Central (United Kingdom)

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.

Song W; Zhang Y; Li G; Chen H; Wang H; Zhao Q; He D; Zhao C; Ding L

2014-01-01

219

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

2013-07-30

220

Quantitation of phosphorothioate oligonucleotides in human blood plasma using a nanoparticle-based method for solid-phase extraction.  

UK PubMed Central (United Kingdom)

Based on the application of cationic polystyrene nanoparticles, a novel method for solid-phase extraction of phosphorothioate oligonucleotides from human plasma has been developed. A high binding affinity, which is required for an effective isolation out of complex mixtures, is mediated by hydrophobic and multiple electrostatic interactions between the oligonucleotides and the nanoparticles. The principle of the method is based on a pH-controlled adsorption/desorption mechanism. Analysis of the extracted samples was performed by capillary gel electrophoresis. Extraction conditions were optimized, providing the isolation of oligonucleotides (> or = 10 nucleotide units) in high yields and purity even at concentrations in the low-nanomolar range (down to 5 nM). The low salt contamination of the samples allows their direct analysis by electrospray mass spectrometry. The combined linearity and accuracy of the assay together with absolute recovery rates in the range of 60-90% indicate that the developed solid-phase extraction method is generally applicable to quantitation of oligonucleotides in human plasma. Further improvement was achieved with an optimized carrier system of 2-fold enlarged particles which reduces the time consumption of the extraction procedure to approximately 30 min.

Maier M; Fritz H; Gerster M; Schewitz J; Bayer E

1998-06-01

 
 
 
 
221

A matrix solid-phase dispersion method for the extraction of seven pesticides from mango and papaya.  

UK PubMed Central (United Kingdom)

A simple and effective extraction method based on matrix solid-phase dispersion was developed to determine trichlorfon, pyrimethanil, methyl parathion, tetraconazole, thiabendazole, imazalil, and tebuconazole in papaya and mango using gas chromatography-mass spectrometry with selected ion monitoring. Different parameters of the method were evaluated, such as type of solid-phase (silica-gel, neutral alumina, and Florisil), the amount of solid-phase, and eluent [dichloromethane, ethyl acetate-dichloromethane (4:1, 1:4, 1:1, 2:3, v/v)]. The best results were obtained using 2.0 g of mango or papaya, 3.0 g of silica as dispersant sorbent, and ethyl acetate-dichloromethane (1:1, v/v) as eluting solvent. The method was validated using mango and papaya samples fortified with pesticides at different concentration levels (0.05, 0.10, and 1.0 mg/kg). Average recoveries (4 replicates) ranged from 80% to 146%, with relative standard deviations between 1.0% and 28%. Detection and quantification limits for mango and papaya ranged from 0.01 to 0.03 mg/kg and 0.05 to 0.10 mg/kg, respectively. The proposed method was applied to the analysis of these compounds in commercial fruit samples from a local market (Aracaju/SE, Brazil), and residues of the pesticides were not detected on the samples.

Navickiene S; Aquino A; Bezerra DS

2010-10-01

222

A matrix solid-phase dispersion method for the extraction of seven pesticides from mango and papaya.  

Science.gov (United States)

A simple and effective extraction method based on matrix solid-phase dispersion was developed to determine trichlorfon, pyrimethanil, methyl parathion, tetraconazole, thiabendazole, imazalil, and tebuconazole in papaya and mango using gas chromatography-mass spectrometry with selected ion monitoring. Different parameters of the method were evaluated, such as type of solid-phase (silica-gel, neutral alumina, and Florisil), the amount of solid-phase, and eluent [dichloromethane, ethyl acetate-dichloromethane (4:1, 1:4, 1:1, 2:3, v/v)]. The best results were obtained using 2.0 g of mango or papaya, 3.0 g of silica as dispersant sorbent, and ethyl acetate-dichloromethane (1:1, v/v) as eluting solvent. The method was validated using mango and papaya samples fortified with pesticides at different concentration levels (0.05, 0.10, and 1.0 mg/kg). Average recoveries (4 replicates) ranged from 80% to 146%, with relative standard deviations between 1.0% and 28%. Detection and quantification limits for mango and papaya ranged from 0.01 to 0.03 mg/kg and 0.05 to 0.10 mg/kg, respectively. The proposed method was applied to the analysis of these compounds in commercial fruit samples from a local market (Aracaju/SE, Brazil), and residues of the pesticides were not detected on the samples. PMID:20875237

Navickiene, Sandro; Aquino, Adriano; Bezerra, Débora Santos Silva

2010-10-01

223

Investigation of improving innovative dioxins analyis method using Solid phase MicroExtraction (SPME)-HRGC-HRMS  

Energy Technology Data Exchange (ETDEWEB)

A new rapid, simple, inexpensive and accurate dioxin extraction and analysis procedure has been developed using Solid Phase Micro Extraction (SPME) coupled with HRGC-HRMS. This innovative, rapid dioxin analysis method uses carbon coated SPME fibers without the complicated sample cleanup steps that are currently being used for conventional dioxin analytical methods. During the development of the new SPME method, we noticed a few problems that needed to be addressed. One is the carryover of isomers after analyzing a sample containing a high concentration of dioxin isomers. The second concern are extracts that can not be concentrated to small volumes, for example, 50-100uL due to precipitation because the extract contains a large amount of interfering sample matrices. This paper describes the research focused on reducing the carryover and the precipitation problems with concentrated samples along with evaluating a new extraction method.

Maeoka, M. [Japan Quality Assurance Organization Kansai Environment Testing Lab., Osaka (Japan); Robillard, M.; Shirey, R. [Supelco, Bellfonte, PA (United States); Kaneko, T. [Sigma-Aldrich Japan, Tokyo (Japan)

2004-09-15

224

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

Scientific Electronic Library Online (English)

Full Text Available 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 concentração de tiocianato sob a extração do ferro, tempo de agitação necessário para extração quantitativa, quantidade de espuma requerida, separação de alumínio d (more) e 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 thiocyanate concentration on the iron extraction, shaking time required for quantitative extraction, amount of PU foam necessary for complete extraction of iron, aluminium separatio (more) n 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.

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

1998-04-01

225

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)

2003-01-01

226

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 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.

2009-01-01

227

Solid-phase extraction of tramadol from plasma and urine samples using a novel water-compatible molecularly imprinted polymer.  

UK PubMed Central (United Kingdom)

In this study, a novel method is described for the determination of tramadol in biological fluids using molecularly imprinted solid-phase extraction (MISPE) as the sample clean-up technique combined with high-performance liquid chromatography (HPLC). The water-compatible molecularly imprinted polymers (MIPs) were prepared using methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linker, chloroform as porogen and tramadol as template molecule. The novel imprinted polymer was used as a solid-phase extraction (SPE) sorbent for the extraction of tramadol from human plasma and urine. Various parameters affecting the extraction efficiency of the polymer have been evaluated. The optimal conditions for the MIP cartridges were studied. The MIP selectivity was evaluated by checking several substances with similar molecular structures to that of tramadol. The limit of detection (LOD) and limit of quantification (LOQ) for tramadol in urine samples were 1.2 and 3.5 microg L(-1), respectively. These limits for tramadol in plasma samples were 3.0 and 8.5 microg L(-1), respectively. The recoveries for plasma and urine samples were higher than 91%.

Javanbakht M; Attaran AM; Namjumanesh MH; Esfandyari-Manesh M; Akbari-Adergani B

2010-06-01

228

Solid-phase extraction of tramadol from plasma and urine samples using a novel water-compatible molecularly imprinted polymer.  

Science.gov (United States)

In this study, a novel method is described for the determination of tramadol in biological fluids using molecularly imprinted solid-phase extraction (MISPE) as the sample clean-up technique combined with high-performance liquid chromatography (HPLC). The water-compatible molecularly imprinted polymers (MIPs) were prepared using methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linker, chloroform as porogen and tramadol as template molecule. The novel imprinted polymer was used as a solid-phase extraction (SPE) sorbent for the extraction of tramadol from human plasma and urine. Various parameters affecting the extraction efficiency of the polymer have been evaluated. The optimal conditions for the MIP cartridges were studied. The MIP selectivity was evaluated by checking several substances with similar molecular structures to that of tramadol. The limit of detection (LOD) and limit of quantification (LOQ) for tramadol in urine samples were 1.2 and 3.5 microg L(-1), respectively. These limits for tramadol in plasma samples were 3.0 and 8.5 microg L(-1), respectively. The recoveries for plasma and urine samples were higher than 91%. PMID:20452295

Javanbakht, Mehran; Attaran, Abdol Mohammad; Namjumanesh, Mohammad Hadi; Esfandyari-Manesh, Mehdi; Akbari-Adergani, Behrouz

2010-04-24

229

[Rapid determination of six preservative residues in fruits and vegetables by high performance liquid chromatography using dispersive solid phase extraction].  

UK PubMed Central (United Kingdom)

A dispersive solid phase extraction-high performance liquid chromatographic (HPLC) method was established for the simultaneous determination of 2,4-D, thiabendazole, 2-naphthol, o-phenyl phenol, diphenyl ether and biphenyl in the fruits and vegetables. The samples were vortexed for extraction with acetonitrile containing sodium chloride and anhydrous magnesium sulfate. The acetonitrile extraction was purified by acidic alumina dispersed solid phase extraction. The analysis was performed on an Agilent TC C18 column (250 mm x 4.6 mm, 5 microm) and an ultraviolet detector at 235 nm with a mobile phase of methanol-0.02 mol/L (pH 6) potassium dihydrogen phosphate solution, at a flow rate of 1.0 mL/min with gradient elution. Good linearities were observed in the range of 0.5-20 mg/L with correlation coefficients greater than 0.99. The average recoveries of the six preservatives in fruits and vegetables were in the range of 84.2% -99. 1% at three spiked levels of 1, 2 and 10 mg/kg (n = 6) and the relative standard deviations (RSDs) were in the range of 1.67%-10.3%. The limits of quantification were 1 mg/kg. This method is simple, accurate and suitable for the determination of the six preservatives in fruits and vegetables.

Lin H; Zou Z; Qin Y; Xie S; Chen Y; Xu J; Wang L; Chen C

2013-02-01

230

Preparation, characterization and application of N-2-Pyridylsuccinamic acid-functionalized halloysite nanotubes for solid-phase extraction of Pb(II).  

UK PubMed Central (United Kingdom)

Halloysite nanotubes (HNTs) were chemically modified with N-2-Pyridylsuccinamic acid (PSA) to produce a new nano-adsorbent (HNTs-PSA) for selective solid-phase extraction of Pb(II). The new adsorbent was characterized by Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM), thermogravimetric analysis (TGA), and elemental analysis to evaluate the surface modification. Under the optimized conditions (pH 5, flow rate 1.5 mL min(-1)), Pb(II) was retained on the column packed with HNTs-PSA, and then was quantitatively eluted by 1.5 mL 0.5 mol L(-1) HCl and determined by inductively coupled plasma-optical emission spectrometry. An enrichment factor of 67 was obtained using 30 mg of HNTs-PSA. The maximum adsorption capacity for Pb(II) was found to be 23.58 mg g(-1). The detection limits of this method for Pb(II) was 0.32 ?g L(-1). The relative standard deviation under optimum conditions was 3.4% (n = 11). The developed method was validated by analyzing a certified reference material, and then successfully applied to the determination of Pb(II) in actual samples.

He Q; Yang D; Deng X; Wu Q; Li R; Zhai Y; Zhang L

2013-08-01

231

Preparation, characterization and application of N-2-Pyridylsuccinamic acid-functionalized halloysite nanotubes for solid-phase extraction of Pb(II).  

Science.gov (United States)

Halloysite nanotubes (HNTs) were chemically modified with N-2-Pyridylsuccinamic acid (PSA) to produce a new nano-adsorbent (HNTs-PSA) for selective solid-phase extraction of Pb(II). The new adsorbent was characterized by Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM), thermogravimetric analysis (TGA), and elemental analysis to evaluate the surface modification. Under the optimized conditions (pH 5, flow rate 1.5 mL min(-1)), Pb(II) was retained on the column packed with HNTs-PSA, and then was quantitatively eluted by 1.5 mL 0.5 mol L(-1) HCl and determined by inductively coupled plasma-optical emission spectrometry. An enrichment factor of 67 was obtained using 30 mg of HNTs-PSA. The maximum adsorption capacity for Pb(II) was found to be 23.58 mg g(-1). The detection limits of this method for Pb(II) was 0.32 ?g L(-1). The relative standard deviation under optimum conditions was 3.4% (n = 11). The developed method was validated by analyzing a certified reference material, and then successfully applied to the determination of Pb(II) in actual samples. PMID:23591107

He, Qun; Yang, Dong; Deng, Xiaoli; Wu, Qiong; Li, Ruijun; Zhai, Yunhui; Zhang, Lijun

2013-03-29

232

Preconcentration and spectrophotometric determination of low concentrations of malachite green and leuco-malachite green in water samples by high performance solid phase extraction using maghemite nanoparticles.  

UK PubMed Central (United Kingdom)

A novel and sensitive extraction procedure using maghemite nanoparticles (gamma-Fe(2)O(3)) modified with sodium dodecyl sulfate (SDS), as an efficient solid phase, was developed for removal, preconcentration and spectrophotometric determination of trace amounts of malachite green (MG) and leuco-malachite green (LMG). Combination of nanoparticle adsorption and easily magnetic separation was used to extraction and desorption of MG and LMG. The adsorption capacity was evaluated using both the Langmuir and Freundlich adsorption isotherm models. Maghemite nanoparticles were prepared by co-precipitation method and their surfaces were modified by SDS. The size and properties of the produced maghemite nanoparticles was determined by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and BET analysis. MG and LMG became adsorbed at pH 3.0. LMG was oxidized to MG by adsorption on maghemite nanoparticles. The adsorbed MG was then desorbed and determined spectrophotometrically. The calibration graph was linear in the range 0.50-250.00 ng mL(-1) of MG and LMG with a correlation coefficient of 0.9991. The detection limit of the method for determination of MG was 0.28 ng mL(-1) and the relative standard deviation (R.S.D.) for 10.00 and 50.00 ng mL(-1) of malachite green was 1.60% (n=3) and 0.86% (n=5), respectively. A preconcentration factor of 50 was achieved in this method. The Langmuir adsorption capacity (q(max)) was found to be 227.3 mg g(-1) of the adsorbent. The method was applied to the determination of MG in fish farming water samples.

Afkhami A; Moosavi R; Madrakian T

2010-07-01

233

Preconcentration and spectrophotometric determination of low concentrations of malachite green and leuco-malachite green in water samples by high performance solid phase extraction using maghemite nanoparticles.  

Science.gov (United States)

A novel and sensitive extraction procedure using maghemite nanoparticles (gamma-Fe(2)O(3)) modified with sodium dodecyl sulfate (SDS), as an efficient solid phase, was developed for removal, preconcentration and spectrophotometric determination of trace amounts of malachite green (MG) and leuco-malachite green (LMG). Combination of nanoparticle adsorption and easily magnetic separation was used to extraction and desorption of MG and LMG. The adsorption capacity was evaluated using both the Langmuir and Freundlich adsorption isotherm models. Maghemite nanoparticles were prepared by co-precipitation method and their surfaces were modified by SDS. The size and properties of the produced maghemite nanoparticles was determined by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and BET analysis. MG and LMG became adsorbed at pH 3.0. LMG was oxidized to MG by adsorption on maghemite nanoparticles. The adsorbed MG was then desorbed and determined spectrophotometrically. The calibration graph was linear in the range 0.50-250.00 ng mL(-1) of MG and LMG with a correlation coefficient of 0.9991. The detection limit of the method for determination of MG was 0.28 ng mL(-1) and the relative standard deviation (R.S.D.) for 10.00 and 50.00 ng mL(-1) of malachite green was 1.60% (n=3) and 0.86% (n=5), respectively. A preconcentration factor of 50 was achieved in this method. The Langmuir adsorption capacity (q(max)) was found to be 227.3 mg g(-1) of the adsorbent. The method was applied to the determination of MG in fish farming water samples. PMID:20602970

Afkhami, Abbas; Moosavi, Razieh; Madrakian, Tayyebeh

2010-06-01

234

Determination of polychlorinated biphenyls in ash using dimethylsulfoxide microwave assisted extraction followed by solid-phase microextraction.  

UK PubMed Central (United Kingdom)

A procedure for the determination of several coplanar and non coplanar PCBs in ash samples is described. Analytes were extracted from the samples using dimethylsulfoxide (DMSO) under the action of a microwave field, and then they were concentrated on a PDMS-DVB solid-phase microextraction (SPME) fibre using the headspace mode, after water dilution of the DMSO extract. Determinations were carried out using GC-ECD and GC-MS detection. Influences of microwave extraction (solvent volume, temperature and time) and SPME conditions (stirring, kind of SPME fibre, salt and water addition, sampling time and temperature) on the performance of the whole analytical procedure were systematically investigated. Working under optimal conditions quantification limits from 0.2 to 1.5ngg(-1) were obtained for all the compounds, except for PCB 209, which could not be consistently extracted from the sample using the proposed conditions.

Criado MR; Pereiro IR; Torrijos RC

2004-06-01

235

Determination of polychlorinated biphenyls in ash using dimethylsulfoxide microwave assisted extraction followed by solid-phase microextraction.  

Science.gov (United States)

A procedure for the determination of several coplanar and non coplanar PCBs in ash samples is described. Analytes were extracted from the samples using dimethylsulfoxide (DMSO) under the action of a microwave field, and then they were concentrated on a PDMS-DVB solid-phase microextraction (SPME) fibre using the headspace mode, after water dilution of the DMSO extract. Determinations were carried out using GC-ECD and GC-MS detection. Influences of microwave extraction (solvent volume, temperature and time) and SPME conditions (stirring, kind of SPME fibre, salt and water addition, sampling time and temperature) on the performance of the whole analytical procedure were systematically investigated. Working under optimal conditions quantification limits from 0.2 to 1.5ngg(-1) were obtained for all the compounds, except for PCB 209, which could not be consistently extracted from the sample using the proposed conditions. PMID:18969465

Criado, M Ramil; Pereiro, I Rodríguez; Torrijos, R Cela

2004-06-17

236

Headspace solid-phase microextraction gas chromatography-mass spectrometry analysis of Eupatorium odoratum extract as an oviposition repellent.  

Science.gov (United States)

Headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) analysis was used to study volatile and semi-volatile compounds emitted by the Eupatorium odoratum (E. odoratum) extract. Variables of HS-SPME such as the type of SPME fiber, extraction time and temperature, incubation time, desorption time and temperature have been optimized. Optimized conditions were obtained by the use of divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber, 5 min/20 min incubation/extraction time at 65 degrees C, 5 min desorption time at 260 degrees C. Using three different polar chromatographic columns to get retention index and mass spectrometry data, 99 volatile and semi-volatile compounds were tentatively identified in the E. odoratum extract. This study has identified the promising source of E. odoratum oviposition repellent. PMID:19501027

Cui, Shufen; Tan, Shuo; Ouyang, Gangfeng; Jiang, Shihong; Pawliszyn, Janusz

2009-05-21

237

Headspace solid-phase microextraction gas chromatography-mass spectrometry analysis of Eupatorium odoratum extract as an oviposition repellent.  

UK PubMed Central (United Kingdom)

Headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) analysis was used to study volatile and semi-volatile compounds emitted by the Eupatorium odoratum (E. odoratum) extract. Variables of HS-SPME such as the type of SPME fiber, extraction time and temperature, incubation time, desorption time and temperature have been optimized. Optimized conditions were obtained by the use of divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber, 5 min/20 min incubation/extraction time at 65 degrees C, 5 min desorption time at 260 degrees C. Using three different polar chromatographic columns to get retention index and mass spectrometry data, 99 volatile and semi-volatile compounds were tentatively identified in the E. odoratum extract. This study has identified the promising source of E. odoratum oviposition repellent.

Cui S; Tan S; Ouyang G; Jiang S; Pawliszyn J

2009-07-01

238

Multiresidue method for the gas chromatographic determination of pesticides in honey after solid-phase extraction cleanup.  

UK PubMed Central (United Kingdom)

A new multiresidue method is described for the determination of pesticides in honey. The method involves dissolution of the honey in a methanol-water mixture, followed by solid-phase extraction cleanup and gas chromatographic determination. Twenty-six pesticides used on flowering field crops, on flowering fruit and vegetables, or as acaricides to control Varroa jacobsoni in beehives are determined by the method. Recoveries from honey, spiked at 0.02-1.6 mg/kg, ranged from 85 to 127% with a relative standard deviation (RSD) of 2-16%, except for the RSD of 27% for captan at 0.05 mg/kg.

Jansson C

2000-05-01

239

Multiresidue method for the gas chromatographic determination of pesticides in honey after solid-phase extraction cleanup.  

Science.gov (United States)

A new multiresidue method is described for the determination of pesticides in honey. The method involves dissolution of the honey in a methanol-water mixture, followed by solid-phase extraction cleanup and gas chromatographic determination. Twenty-six pesticides used on flowering field crops, on flowering fruit and vegetables, or as acaricides to control Varroa jacobsoni in beehives are determined by the method. Recoveries from honey, spiked at 0.02-1.6 mg/kg, ranged from 85 to 127% with a relative standard deviation (RSD) of 2-16%, except for the RSD of 27% for captan at 0.05 mg/kg. PMID:10868595

Jansson, C

240

A sensitive and selective molecularly imprinted sensor combined with magnetic molecularly imprinted solid phase extraction for determination of dibutyl phthalate.  

UK PubMed Central (United Kingdom)

A highly sensitive and selective molecularly imprinted (MIP) sensor combined with magnetic molecularly imprinted solid phase extraction (MMISPE) was developed for the determination of dibutyl phthalate (DBP) in complex matrixes. The magnetic molecularly imprinted polymer (MMIP) was synthesized as solid phase extraction (SPE) sorbet to extract DBP from complex matrixes and as sensing element to improve the selectivity of the imprinted sensor. The morphologies of MMIP and MIP-sensor were characterized by using scanning electron microscope (SEM) and transmission electron microscopy (TEM). The electrochemical performances of MIP-sensor were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The conditions of preconcentration, elution and electrochemical determination were studied in detail. Under the optimized experimental conditions, the response currents of the MIP-sensor exhibited a linear relationship towards DBP concentrations ranging from 1.0 × 10(-8)g/L to 1.0 × 10(-3)g/L. The limit of detection of the MMIP-sensor coupled with the MMISPE was calculated as 0.052 ng/L. The MMIP-sensor coupled with the MMISPE was applied to detect DBP in complex samples successfully.

Zhang Z; Luo L; Cai R; Chen H

2013-11-01

 
 
 
 
241

Molecularly imprinted solid-phase extraction coupled to liquid chromatography for determination of Sudan dyes in preserved beancurds  

UK PubMed Central (United Kingdom)

New molecularly imprinted microspheres synthesized by suspension polymerisation using phenylamine and naphthol as mimic template were successfully applied as selective sorbents for the solid-phase extraction used for the simultaneous determination of four Sudan dyes from preserved beancurd products. The obtained imprinted microspheres showed good recognition and selectivity to the four Sudan dyes in aqueous solution and the affinity could be easily controlled by adjusting the property of the solution. Under the selected experimental condition, the recoveries of the Sudan dyes in preserved beancurds at three spiked levels were ranged between 90.2–104.5% with the relative standard deviation of less than 6.8%. The limit of detection (LOD) and limit of quantification (LOQ) based on a signal-to-noise of 3 and 10 were in the range of 0.005–0.009?gg?1 and 0.015–0.030?gg?1, respectively. Comparing with alumina and C18-based extraction, the selectivity and repeatability of molecularly imprinted solid-phase extraction (MISPE) were obviously improved. This method could be potentially applied for the determination of Sudan dyes in complicated food samples.

Yan H; Qiao J; Pei Y; Long T; Ding W; Xie K

2012-05-01

242

A sensitive and selective molecularly imprinted sensor combined with magnetic molecularly imprinted solid phase extraction for determination of dibutyl phthalate.  

Science.gov (United States)

A highly sensitive and selective molecularly imprinted (MIP) sensor combined with magnetic molecularly imprinted solid phase extraction (MMISPE) was developed for the determination of dibutyl phthalate (DBP) in complex matrixes. The magnetic molecularly imprinted polymer (MMIP) was synthesized as solid phase extraction (SPE) sorbet to extract DBP from complex matrixes and as sensing element to improve the selectivity of the imprinted sensor. The morphologies of MMIP and MIP-sensor were characterized by using scanning electron microscope (SEM) and transmission electron microscopy (TEM). The electrochemical performances of MIP-sensor were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The conditions of preconcentration, elution and electrochemical determination were studied in detail. Under the optimized experimental conditions, the response currents of the MIP-sensor exhibited a linear relationship towards DBP concentrations ranging from 1.0 × 10(-8)g/L to 1.0 × 10(-3)g/L. The limit of detection of the MMIP-sensor coupled with the MMISPE was calculated as 0.052 ng/L. The MMIP-sensor coupled with the MMISPE was applied to detect DBP in complex samples successfully. PMID:23796536

Zhang, Zhaohui; Luo, Lijuan; Cai, Rong; Chen, Hongjun

2013-06-06

243

Fractionation of fatty acids derived from soil lipids by solid phase extraction and their quantitative analysis by GC-MS.  

UK PubMed Central (United Kingdom)

To provide a procedure to estimate microbial biomass and community structure, an analytical method for the quantitative measurement of the profile of fatty acids derived from phospholipid (PL) and lipopolysacchride (LPS) in agricultural soil was developed and evaluated. The lipids were extracted by the one-phase procedure, and the PL was separated from other fractions by a solid phase column. Then, the PL was subjected to a mild alkaline hydrolysis to form fatty acid methyl esters (FAMEs). The hydroxy fatty acids methyl esters (OHFAMEs) derived from LPS in the soil studied were obtained by acidic hydrolysis of the extracted soil residue, followed by methylation. The FAMEs were further cleaned up and separated into several subgroups by utilization of consecutive solid phase columns. To measure the OHFAMEs and monoenoic FAMEs, these compounds needed further trimethylsilylization and dimethyl disulphide derivatization, respectively, before injection. Qualitative and quantitative measurements were made by an internal standard method using a GC-MS system. More than 160 fatty acids derived from PL and several dozens of hydroxy fatty acids derived from LPS in the soil have been found. The total amount of PL-FAs in the soil were found to be 23 micrograms g-1. In contrast, the OHFAs derived from LPS amounted to only 519 ng g-1. As little as a few ng g-1 of these fatty acids present in the PL-fraction could be detected by this method. The recovery of bacterial standard FAMEs was between 73 and 104% after consecutive separation of FAMEs into various subgroups using solid phase columns. The diversity of the fatty acids may reflect the complexity of microorganisms present in the soil studied.

Zelles L; Bai QY

1993-04-01

244

Automated sample preparation by pressurized liquid extraction-solid-phase extraction for the liquid chromatographic-mass spectrometric investigation of polyphenols in the brewing process.  

Science.gov (United States)

The analysis of polyphenols from solid plant or food samples usually requires laborious sample preparation. The liquid extraction of these compounds from the sample is compromised by apolar matrix interferences, an excess of which has to be eliminated prior to subsequent purification and separation. Applying pressurized liquid extraction to the extraction of polyphenols from hops, the use of different solvents sequentially can partly overcome these problems. Initial extraction with pentane eliminates hydrophobic compounds like hop resins and oils and enables the straightforward automated on-line solid-phase extraction as part of an optimized LC-MS analysis. PMID:12462627

Papagiannopoulos, Menelaos; Mellenthin, Annett

2002-11-01

245

Automated sample preparation by pressurized liquid extraction-solid-phase extraction for the liquid chromatographic-mass spectrometric investigation of polyphenols in the brewing process.  

UK PubMed Central (United Kingdom)

The analysis of polyphenols from solid plant or food samples usually requires laborious sample preparation. The liquid extraction of these compounds from the sample is compromised by apolar matrix interferences, an excess of which has to be eliminated prior to subsequent purification and separation. Applying pressurized liquid extraction to the extraction of polyphenols from hops, the use of different solvents sequentially can partly overcome these problems. Initial extraction with pentane eliminates hydrophobic compounds like hop resins and oils and enables the straightforward automated on-line solid-phase extraction as part of an optimized LC-MS analysis.

Papagiannopoulos M; Mellenthin A

2002-11-01

246

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; XIAO GUO WANG; JUN ZHANG

2009-01-01

247

Development of novel amphiphilic magnetic molecularly imprinted polymers compatible with biological fluids for solid phase extraction and physicochemical behavior study.  

UK PubMed Central (United Kingdom)

In the present work, a novel amphiphilic magnetic molecularly imprinted polymer (M-MIP) has been synthesized by a simple non covalent method for the loading of gatifloxacin (GTFX) in polar solvent. This nanomaterial used as sorbent has been applied to the solid phase extraction of GTFX in different spiked biological fluids. For the first time, studies of dispersibility and solubility behaviors with different solvents and water were performed to demonstrate amphiphilicity and also to find the better nanomaterial obtained. Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray (XRD) were used to characterize the nanomaterials, and Scatchard plot analysis to demonstrate the binding kinetic. Results suggest that the dispersibility, solubility and the adsorption in water have relationships with the structure of nanomaterials prepared. The oleic acid coated on the M-MIP combined with the washing process has enhanced the amphiphilicity of the nanomaterials. The M-MIP2 showed better selectivity and adsorption behavior with imprinted efficiency higher than (2) in water, as well as in biological fluids. Moreover, no interference with constituents of blank urine and blank serum samples for solid phase extraction (SPE) was observed. Moreover, loading recovery was found higher than 95% with low RSD. The novel amphiphilic magnetic nanomaterial prepared here as sorbent is suitable for SPE of GTFX in biological fluids for therapeutic monitoring control. It could be also used as carrier in drug delivery system for experimental and clinical studies.

Dramou P; Zuo P; He H; Pham-Huy LA; Zou W; Xiao D; Pham-Huy C

2013-07-01

248

[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

249

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

UK PubMed Central (United Kingdom)

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.

Yu T; Li Q; Wan T; Li J; Ding S

2011-02-01

250

Analysis of some cytokinins in coconut (Cocos nucifera L.) water by micellar electrokinetic capillary chromatography after solid-phase extraction.  

UK PubMed Central (United Kingdom)

Micellar electrokinetic capillary chromatography (MECC) was developed for the separation of cytokinins including trans-zeatin, trans-zeatin-O-glucoside, dihydrozeatin, dihydrozeatin-O-glucoside, meta-topolin riboside, N6-isopentenyladenine and N6-benzylaminopurine. Under the optimum conditions, i.e. a combination of 10 mM phosphate and 10 mM borate as the running buffer containing 50 mM sodium dodecyl sulphate at pH 10.4, the separation of seven cytokinin standards was accomplished within 11 min. The C18 solid-phase extraction (SPE) method was used to pre-concentrate the putative cytokinins present in the coconut water. Following which, the eluate was further purified using mixed mode Oasis MCX SPE columns and this additional step helps to reduce matrix interference during MECC. After the two solid-phase extraction steps, the optimized MECC method was able to screen for certain cytokinins (zeatin-O-glucoside and dihydrozeatin-O-glucoside) present in coconut water. After this screening, the presence of zeatin-O-glucoside and dihydrozeatin-O-glucoside in coconut water was further confirmed by independent high-performance liquid chromatography and liquid chromatography-mass spectrometry experiments.

Ge L; Yong JW; Tan SN; Yang XH; Ong ES

2004-09-01

251

Solid phase extractive preconcentration of uranium(VI) using quinoline-8-ol anchored chloromethylated polymeric resin beads.  

UK PubMed Central (United Kingdom)

A new chelating polymeric sorbent has been developed using Merrifield chloromethylated resin anchored with quinoline-8-ol (HQ). The modified polymeric resin was characterized by FT-IR spectroscopy and elemental analysis. The HQ anchored resin showed superior binding affinity for U(VI) over Th(IV) and La(III). The influence of various physicochemical parameters on the recovery of U(VI) were optimized by both static and dynamic methods. The phase exchange kinetic studies performed for U(VI) revealed that <5min was sufficient for reaching equilibrium metal ion sorption. The maximum sorption capacity of HQ anchored resin for U(VI) was found to be 120.30mgg(-1) of resin which is higher than other solid phase extraction sorbents reported so far excepting N,N-dibutyl, N'-benzoyl thiourea sorbed Amberlite XAD-16. The developed HQ anchored polymeric resin is highly selective as none of the extraneous species were found to have any deleterious effect. Solid phase extraction (SPE) studies performed using HQ anchored polymeric resin offered enrichment factor of 100 and the lowest concentration below which recoveries become non-quantitative is 5mugl(-1). The accuracy of the developed SPE method in conjunction with Arsenazo III procedure was tested by analyzing marine sediment (MESS-3) and soil (IAEA-Soil 7) reference materials. Furthermore, the above procedure has been successfully employed for the analysis of real soil and sediment samples.

Praveen RS; Metilda P; Daniel S; Rao TP

2005-10-01

252

[Standardization of "exchange" techniques to measure estradiol receptors in extracts exposed to biospecific adsorbants  

UK PubMed Central (United Kingdom)

The measurement of the binding of steroid hormone receptors to biospecific adsorbants requires the development of "exchange" techniques. Two types of techniques based on the principle of differential dissociation were standardized: solid phase exchange with hydroxylapatite and liquid phase exchange with adsorption of the ligand to charcoal dextran. In both cases, binding of oestradiol to its receptor was measured in calf uterine cytosol extracts. Results obtained by both techniques were comparable. The half-times of the oestradiol-receptor complex dissociation determined from exchange kinetics are on the same order as those obtained by direct methods used in previous studies.

Truong H; Soulignac O; Baulieu EE

1975-05-01

253

SOLID-PHASE EXTRACTION AND HPLC-MS PROFILING OF PYRROLIZIDINE ALKALOIDS AND THEIR N-OXIDES: A CASE STUDY OF ECHIUM PLANTAGINEUM  

Science.gov (United States)

Pyrrolizidine alkaloids and their N-oxides can be extracted from the dried methanolic extracts of plant material using dilute aqueous acid. The subsequent integration of solid-phase extraction (with a strong cation exchanger) of the alkaloids and N-oxides from the aqueous acid solution, together wi...

254

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%.

2008-01-01

255

Zeolitic imidazolate framework-8 as sorbent of micro-solid-phase extraction to determine estrogens in environmental water samples.  

UK PubMed Central (United Kingdom)

A novel micro-solid-phase extraction (?-SPE) device coupled with ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) was established to determine five typical estrogens in aqueous samples. Zeolitic imidazolate framework-8 (ZIF-8) as sorbent was packed in polypropylene membrane to construct the ?-SPE device. Important extraction parameters including extraction time, extraction temperature, desorption solvent, desorption time and sample pH were carefully optimized to improve the extraction efficiency of the ?-SPE device. ZIF-8 sorbent showed an exceptional chemical stability and extraction efficiency for estrogens. In theory, the high extraction efficiencies may be due to the coordination bonding, intermolecular ?-? interactions and hydrophobic interactions between ZIF-8 and the estrogens. Under the most favorable extraction conditions, for estrogens in aqueous samples, the proposed method provided low limits of detection (0.05-0.1?g/L), wide linearity range (three orders), excellent correlation coefficients (0.959-0.999) and satisfactory measurement precision (4.9-9.2%). which can meet the demand of determining estrogens at the trace level. Finally, the proposed method was successfully applied to determine the estrogens in real sewage water samples.

Wang Y; Jin S; Wang Q; Lu G; Jiang J; Zhu D

2013-05-01

256

Gas-chromatographic quantification of methylphenidate in plasma with use of solid-phase extraction and nitrogen-sensitive detection.  

Science.gov (United States)

The gas-chromatographic assay for methylphenidate described here involves isolation by solid-phase extraction and quantification by thermionic nitrogen-phosphorus detection. Methylphenidate and the internal standard, ethylphenidate, are extracted from plasma by partition onto C2 reversed-phase packing. Methylphenidate and ethylphenidate are eluted, dried, derivatized with trifluoroacetic anhydride, and gas-chromatographed, with nitrogen-sensitive detection. The standard curve for the assay is linear in the range 5-100 micrograms/L. The within-run CV is less than 4%, the between-run CV less than 6%. Mean analytical recovery of methylphenidate was greater than 90%. The smallest measurable concentration is 2 micrograms/L. The sensitivity, reproducibility, and economy of this assay make it suitable for clinical monitoring and pharmacokinetic studies. PMID:6744589

Potts, B D; Martin, C A; Vore, M

1984-08-01

257

Gas-chromatographic quantification of methylphenidate in plasma with use of solid-phase extraction and nitrogen-sensitive detection.  

UK PubMed Central (United Kingdom)

The gas-chromatographic assay for methylphenidate described here involves isolation by solid-phase extraction and quantification by thermionic nitrogen-phosphorus detection. Methylphenidate and the internal standard, ethylphenidate, are extracted from plasma by partition onto C2 reversed-phase packing. Methylphenidate and ethylphenidate are eluted, dried, derivatized with trifluoroacetic anhydride, and gas-chromatographed, with nitrogen-sensitive detection. The standard curve for the assay is linear in the range 5-100 micrograms/L. The within-run CV is less than 4%, the between-run CV less than 6%. Mean analytical recovery of methylphenidate was greater than 90%. The smallest measurable concentration is 2 micrograms/L. The sensitivity, reproducibility, and economy of this assay make it suitable for clinical monitoring and pharmacokinetic studies.

Potts BD; Martin CA; Vore M

1984-08-01

258

[Simultaneous determination of saccharin sodium and synthetic colours in flavourings by solid phase extraction and high performance liquid chromatography].  

UK PubMed Central (United Kingdom)

A method for the simultaneous determination of saccharin sodium and synthetic colours in flavourings by solid phase extraction (SPE) and high performance liquid chromatography with variable wavelengths was established. After degreased with petroleum ether, extracted, purified with SPE, and concentrated, the sample was separated on a C18 column with a gradient elution of 0.02 mol/L ammonium acetate and methanol, and detected at 230, 510, 484 and 510 nm, separately. The saccharin sodium and synthetic colours were separated with this method. The recoveries were 88.6% - 97.1% with the RSD < 5%. The limit of detection was 0.05 mg/kg for all the analytes. The proposed method is simple, reliable and reproducible, and especially suitable for a lot of sample detections of saccharin sodium and synthetic colours in flavourings.

Zhao F; Gao G; Na H; Ma D; Wang X

2013-05-01

259

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 < 6%) was obtained. The present 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

260

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 variability and recovery in the heavily contaminated samples compared to SRMs could be mainly contributed to subsample heterogeneity.

2003-01-01

 
 
 
 
261

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

262

Synthesis of surface molecularly imprinted polymer and the selective solid phase extraction of imidazole from its structural analogs.  

UK PubMed Central (United Kingdom)

A surface molecularly imprinted polymer (MIP) was synthesized by using imidazole as the template and modified silica particles as the support material. The static adsorption, solid phase extraction (SPE) and high-performance liquid chromatography (HPLC) experiments were performed to investigate the adsorption properties and selective recognition characteristics of the polymer for imidazole and its structural analogs. It was shown that the maximum binding capacities of imidazole on the MIP and the non-imprinted polymer (NIP) were 312 and 169 ?mol g(-1), respectively. The adsorption was fast and the adsorption equilibrium was achieved in 30 min. The binding process could be described by pseudo-second order kinetics. Compared with the corresponding non-imprinted polymer, the molecularly imprinted polymer exhibited much higher adsorption performance and selectivity for imidazole. The selective separation of imidazole from a mixture of 1-hexyl-3-methylimidazolium bromide ([C(6)mim][Br]) and 2,4-dichlorophenol could be achieved on the MIP-SPE column. The recoveries of imidazole and [C(6)mim][Br] were 97.6-102.7% and 12.2-17.3%, respectively, but 2,4-dichlorophenol could not be retained on the column. The surface molecularly imprinted polymer presented here may find useful application as a solid phase absorbent to separate trace imidazole in environmental water samples. This may also form the basis for our research program on the preparation and application of alkyl-imidazolium imprinted polymers.

Zhu G; Fan J; Gao Y; Gao X; Wang J

2011-05-01

263

Development of a selective solid phase extraction method for nitro musk compounds in environmental waters using a molecularly imprinted sorbent.  

UK PubMed Central (United Kingdom)

A powerful analytical method for the determination of the family of the nitro musk compounds at trace level in environmental waters-river, sea, and water from a treatment plant-is presented. The method is based on the use of molecularly imprinted silica (MIS) as sorbent for solid phase extraction (SPE) used for the clean-up and the concentration step of the target analytes previous to their determination by gas chromatography-mass spectrometry. The optimized extraction procedure allowed extraction recoveries between 61% and 87% using the MIS. The comparison with a non-imprinted silica (NIS) sorbent, for which extraction recoveries between 8% and 26% were obtained, showed the high selectivity of the MIS for the nitro musks. Moreover, high enrichment factors, ranging between 580 and 827, were achieved. The imprinted sorbent was compared to a conventional polymeric SPE sorbent for the extraction of the target compounds from environmental waters, showing high selectivity of the MIS and its clean-up potential. For the first time, the five nitro musk compounds were selectively extracted with an imprinted material.

Lopez-Nogueroles M; Lordel-Madeleine S; Chisvert A; Salvador A; Pichon V

2013-06-01

264

Development of a selective solid phase extraction method for nitro musk compounds in environmental waters using a molecularly imprinted sorbent.  

Science.gov (United States)

A powerful analytical method for the determination of the family of the nitro musk compounds at trace level in environmental waters-river, sea, and water from a treatment plant-is presented. The method is based on the use of molecularly imprinted silica (MIS) as sorbent for solid phase extraction (SPE) used for the clean-up and the concentration step of the target analytes previous to their determination by gas chromatography-mass spectrometry. The optimized extraction procedure allowed extraction recoveries between 61% and 87% using the MIS. The comparison with a non-imprinted silica (NIS) sorbent, for which extraction recoveries between 8% and 26% were obtained, showed the high selectivity of the MIS for the nitro musks. Moreover, high enrichment factors, ranging between 580 and 827, were achieved. The imprinted sorbent was compared to a conventional polymeric SPE sorbent for the extraction of the target compounds from environmental waters, showing high selectivity of the MIS and its clean-up potential. For the first time, the five nitro musk compounds were selectively extracted with an imprinted material. PMID:23618185

Lopez-Nogueroles, Marina; Lordel-Madeleine, Sonia; Chisvert, Alberto; Salvador, Amparo; Pichon, Valérie

2013-02-18

265

Multiresidue analysis of pesticides in fruits and vegetables using solid-phase extraction and gas chromatographic methods.  

Science.gov (United States)

A new extraction and cleanup procedure with gas chromatography was developed for the sensitive determination of acephate, dimethoate, malathion, diazinon, quinalphos, chlorpyrifos, profenofos, alpha-endosulfan, beta-endosulfan, chlorothalonil and carbaryl using 1-chloro-4-fluorobenzene as an internal standard in fruits and vegetables. Several extracting and eluting solvents for solid-phase extraction were investigated. The overall extracting solvent with a mixture of acetone:ethyl acetate:hexane (10:80:10, v/v/v) and a eluting solvent of 5% acetone in hexane used with the RPC18 cartridge gave the best recovery for all of the investigated pesticides, and minimized the interference from co-extractants. Under the optimal extraction and clean-up conditions, recoveries of 85 - 99% with RSD < 5.0% (n = 3) for most of the pesticides at the 0.02 - 0.5 mg/kg level were obtained. The limit of detection was between 0.005 - 0.01 mg/kg and the limit of quantification was 0.01 mg/kg. This analytical procedure was characterized with high accuracy and acceptable sensitivity to meet requirements for monitoring pesticides in crops. PMID:18270414

Lal, Asha; Tan, Guanhuat; Chai, Meekin

2008-02-01

266

Multiresidue analysis of pesticides in fruits and vegetables using solid-phase extraction and gas chromatographic methods.  

UK PubMed Central (United Kingdom)

A new extraction and cleanup procedure with gas chromatography was developed for the sensitive determination of acephate, dimethoate, malathion, diazinon, quinalphos, chlorpyrifos, profenofos, alpha-endosulfan, beta-endosulfan, chlorothalonil and carbaryl using 1-chloro-4-fluorobenzene as an internal standard in fruits and vegetables. Several extracting and eluting solvents for solid-phase extraction were investigated. The overall extracting solvent with a mixture of acetone:ethyl acetate:hexane (10:80:10, v/v/v) and a eluting solvent of 5% acetone in hexane used with the RPC18 cartridge gave the best recovery for all of the investigated pesticides, and minimized the interference from co-extractants. Under the optimal extraction and clean-up conditions, recoveries of 85 - 99% with RSD < 5.0% (n = 3) for most of the pesticides at the 0.02 - 0.5 mg/kg level were obtained. The limit of detection was between 0.005 - 0.01 mg/kg and the limit of quantification was 0.01 mg/kg. This analytical procedure was characterized with high accuracy and acceptable sensitivity to meet requirements for monitoring pesticides in crops.

Lal A; Tan G; Chai M

2008-02-01

267

Multidimensional gas chromatography-mass spectrometry determination of 3-alkyl-2-methoxypyrazines in wine and must. A comparison of solid-phase extraction and headspace solid-phase extraction methods.  

UK PubMed Central (United Kingdom)

Two different strategies for the quantitative determination of 3-alkyl-2-methoxypyrazines in wine and must have been developed and validated. Comparison between both the techniques has been presented and the most adequate has been applied to the determination of these compounds in different samples of wine, made from several varieties of grapes, and also in different samples of must made from Cabernet Sauvignon grapes. Both the methods consisted of a dynamic headspace coupled with a solid-phase extraction (HS-SPE) and solid-phase extraction (SPE) directly from the sample, coupled with multidimensional gas chromatography-mass spectrometry system (MDGC-MS). Both of them require resins LiChrolut EN, and analyte elution has been carried out with dichloromethane. The repeatability of both methodologies was evaluated at two concentration levels. The relative standard deviations (RSD%) were acceptable in every case, but smaller when working with HS-SPE. The recoveries obtained for the three analytes with the two methodologies were almost 100%, with the exception of IBMP, which had a recovery of only 70% with HS-SPE. The linearity was satisfactory with both methods for the range of occurrence of methoxypyrazines in wine and must. The limits of detection of the direct SPE technique were much lower than those of HS-SPE in every case. Direct SPE method detection limits ranged from 0.09 to 0.15 ng L(-1). The method based on direct SPE was chosen finally because it had better detection limits and was easier and quicker than the HS-SPE-based method. It has been applied to the determination of these components in 36 wine and 17 musts samples. The quantitative results suggest that the Spanish wines show meaningless amounts of these compounds. IBMP has been found just in between 1.9 and 15 ng L(-1).

Culleré L; Escudero A; Campo E; Cacho J; Ferreira V

2009-05-01

268

Recovery of atrazine, bromacil, chlorpyrifos, and metolachlor from water samples after concentration on solid-phase extraction disks: interlaboratory study.  

Science.gov (United States)

An interlaboratory comparison was conducted in 1997 and 1998 to examine the feasibility of using C18 solid-phase extraction disks (Empore) to simultaneously determine the herbicides atrazine, bromacil, and metolachlor and the insecticide chlorpyrifos in water samples. A common fortification source and sample processing procedure were used to minimize variation in initial concentrations and operator inconsistencies. The protocol consisted of paired laboratories in different locations coordinating their activities and shipping fortified water samples (deionized or local surface water) or Empore disks on which the pesticides had been retained and then quantitating the analytes by a variety of gas chromatographic methods. Average recoveries from all laboratories were >80% for atrazine, bromacil, and metolachlor, and >70% for chlorpyrifos. Detection of bromacil was unachievable at some locations because of chromatographic problems. Shipping samples between cooperating laboratories did not affect the recovery of atrazine, chlorpyrifos, or metolachlor in either matrix. Recoveries tended to be higher from disks shipped to cooperating laboratories compared with those from fortified water. Shipping disks eliminated many problems associated with the shipment of water samples, such as bottle breakage, higher shipping cost, and possible pesticide degradation. Recoveries of bromacil and metolachlor were lower from fortified surface water samples than from fortified deionized water samples. This collaborative research demonstrated that pesticides in water samples can be concentrated on solid-phase extraction disks at one location and quantitated under diverse analytical conditions at another location. The extraction efficiencies of the disks were comparable with or better than the recoveries obtained from the shipped water samples, and the problems associated with shipping water samples were eliminated by using the disks. PMID:11128134

Mueller, T C; Senseman, S A; Wauchope, R D; Clegg, C; Young, R W; Southwick, L M; Riley, M B; Moye, H A; Dumas, J A; Mersie, W; Mattice, J D; Leidy, R B

269

[Simultaneous determination of four mercapturic acids in human urine using solid phase extraction and liquid chromatography-tandem mass spectrometry].  

UK PubMed Central (United Kingdom)

A method was developed for the simultaneous extraction and determination of four mercapturic acids (MAs), N-acetyl-S-(3,4-dihydroxybutyl)-L-cysteine (DHBMA), N-acetyl-S-(3-hydroxypropyl)-L-cysteine (3-HPMA), N-acetyl-S-(2-carboxyethyl)-L-cysteine ( CEMA) and S-phenylmercapturic acid (SPMA), in human urine using solid phase extraction and high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Frozen urine samples were thawed at room temperature, and centrifuged to remove any settled precipitate. The supernatant was then purified and concentrated by a C18 solid phase extraction column, and analyzed by HPLC-MS/MS in the multiple reaction monitoring (MRM) mode for the quantitative analysis. The ranges of recovery for DHBMA, 3-HPMA, CEMA and SPMA spiked in human urine matrix at three concentration levels were 105.6%-124.4%, 102.7%-106.5%, 103.2%-103.9% and 101.7%-104.3%, respectively, with the relative standard deviations of 2.6%-7.7%. The limits of detection (LOD, S/N > or = 3) were 0. 062, 0. 031, 0. 020 and 0. 003 microg/L for DHBMA, 3-HPMA, CEMA and SPMA, respectively. The method was successfully used to detect 4 MAs in 37 human urine samples from smokers and non-smokers. It was found that the contents of 3-HPMA, CEMA and SPMA in the urines from cigarette smokers were about three to six-fold more than those in the urines from the non-smokers.

Hou H; Xiong W; Gao N; Song D; Tang G; Hu Q

2011-01-01

270

[Simultaneous determination of benzotriazoles and benzothiazole in surface water by solid phase extraction and high performance liquid chromatography].  

Science.gov (United States)

A simple method based on solid phase extraction (SPE) coupled with high performance liquid chromatography (HPLC) was developed for the determination of 1H-benzotriazole (BT), 5-methyl-1H-benzotriazole (5-M-BT), 5,6-dimethyl-1H-benzotriazole (5,6-DM-BT), 5-chloro-1H-benzotriazole (5-Cl-BT) and benzothiazole (BTH) in surface water. The extraction and clean-up of the surface water sample were performed on an HLB solid-phase extraction cartridge. The separation of the five compounds was achieved on a ZORBAX SB-C18 column (250 mm x 4.6 mm, 5 microm) with methanol-water (55:45, v/v) as mobile phase and ultraviolet detection. The quantification was achieved by external standard method. The results showed that good linearities were observed in the ranges of 0.064-80 mg/L with the correlation coefficients > or = 0.999 9 and the instrumental limits of detection for the five target compounds were in the range of 1.9-3.2 microg/L. The average recoveries of the five target compounds were 87.8%-125.6% and the relative standard deviations (n = 3) were 0.4%-9.4%. This method was applied to the analysis of the surface water samples from the Dalian tap water and the Liaohe River estuary. The results showed that BT, 5-M-BT, 5-Cl-BT and BTH were found in the water from the Liaohe River estuary. PMID:23697178

Wang, Jincheng; Xiong, Li; Zhang, Haijun; Wang, Longxing; Jin, Jing; Chen, Jiping

2013-02-01

271

[Simultaneous determination of benzotriazoles and benzothiazole in surface water by solid phase extraction and high performance liquid chromatography].  

UK PubMed Central (United Kingdom)

A simple method based on solid phase extraction (SPE) coupled with high performance liquid chromatography (HPLC) was developed for the determination of 1H-benzotriazole (BT), 5-methyl-1H-benzotriazole (5-M-BT), 5,6-dimethyl-1H-benzotriazole (5,6-DM-BT), 5-chloro-1H-benzotriazole (5-Cl-BT) and benzothiazole (BTH) in surface water. The extraction and clean-up of the surface water sample were performed on an HLB solid-phase extraction cartridge. The separation of the five compounds was achieved on a ZORBAX SB-C18 column (250 mm x 4.6 mm, 5 microm) with methanol-water (55:45, v/v) as mobile phase and ultraviolet detection. The quantification was achieved by external standard method. The results showed that good linearities were observed in the ranges of 0.064-80 mg/L with the correlation coefficients > or = 0.999 9 and the instrumental limits of detection for the five target compounds were in the range of 1.9-3.2 microg/L. The average recoveries of the five target compounds were 87.8%-125.6% and the relative standard deviations (n = 3) were 0.4%-9.4%. This method was applied to the analysis of the surface water samples from the Dalian tap water and the Liaohe River estuary. The results showed that BT, 5-M-BT, 5-Cl-BT and BTH were found in the water from the Liaohe River estuary.

Wang J; Xiong L; Zhang H; Wang L; Jin J; Chen J

2013-02-01

272

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 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.

2003-04-15

273

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

2012-12-02

274

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

UK PubMed Central (United Kingdom)

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%.

Rezaei F; Yamini Y; Moradi M; Ebrahimpour B

2013-02-01

275

Determination of cocaine in human plasma by selective solid-phase extraction using an aptamer-based sorbent.  

UK PubMed Central (United Kingdom)

A complete characterization is presented of a highly selective solid-phase extraction (SPE) sorbent which exploits the properties of aptamers. An oligosorbent based on aptamers immobilized on a solid support was synthesized and tested for the selective extraction of cocaine from human plasma. Anticocaine aptamers were immobilized to CNBr-activated Sepharose, and an extraction procedure was developed in pure media. Specific retention of cocaine on the oligosorbent was demonstrated, and the capacity of the support was determined. This oligosorbent was then applied to the selective extraction of cocaine from plasma at a concentration of 0.4 mg L(-1), i.e., corresponding to the plasma concentration reached after an intake of a single dose of cocaine. Extraction recovery close to 90% was obtained. Moreover, interfering compounds that perturbed cocaine quantification when using a standard SPE sorbent were not retained on the oligosorbent, thus allowing fast and reliable analyses of plasma samples with an estimated limit of detection of 0.1 microg mL(-1).

Madru B; Chapuis-Hugon F; Peyrin E; Pichon V

2009-08-01

276

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

UK PubMed Central (United Kingdom)

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.

Bortolomeazzi R; Munari M; Anese M; Verardo G

2012-12-01

277

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 ...

278

Comparison of matrix-solid phase dispersion and liquid-liquid extraction for the chromatographic determination of fenthion and its metabolites in olives and olive oils  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract A matrix-solid phase dispersion (MSPD) methodology has been developed to extract fenthion and its metabolites from olives and olive oils and compared with a conventional liquid-liquid extraction (LLE) procedure. The pesticide residues were analyzed by gas chromatography using a nitr...

279

Flame Atomic Absorption Spectrometric Determination of Trace Amounts of Zinc and Thallium in Different Matrixes after Solid Phase Extraction on Modified Multiwalled Carbon Nanotubes  

Directory of Open Access Journals (Sweden)

Full Text Available The potential of modified multiwallcd carbon nanotubes, as a solid-phase extraction sorbent for the simultaneous separation and preconcentration of zinc and thallium has been investigated. Zinc and thallium were adsorbed quantitatively onto modified multiwalled carbon nanotubes in the pH range of 3 - 6.5. Parameters influencing the simultaneous preconcentration of Zn(II) and Tl(I) ions such as pH of the sample, sample and eluent flow rate, type and volume of elution solution and interfering ions, have been examined and optimized. Linearity was maintained between 0.1 to 20.0 µg?mL–1 for thallium and 20.0 ng?mL–1 to 5.0 µg?mL–1 for zinc in the final solution. The defection limits based on three times the standard deviation of the blank signal (n = 8) for thallium and zinc were 5.1 and 1.4 ng?mL–1, respectively. Seven replicate determination of a mixture of 5.0 and 0.2 µg?mL–1 of thallium and zinc in the final solution gave a mean absorbance of 0.085 and 0.074 with relative standard deviation 1.5% and 1.7%, respectively. The method has been applied for the determination of trace amounts of zinc and thallium in biological and water sample with satisfactory results.

Sayed Zia Mohammadi

2012-01-01

280

Ionic liquids modified dummy molecularly imprinted microspheres as solid phase extraction materials for the determination of clenbuterol and clorprenaline in urine.  

Science.gov (United States)

New ionic liquid modified dummy molecularly imprinted microspheres (DMIMs) were synthesized by aqueous suspension polymerization using phenylephrine as dummy template and 1-allyl-3-ethylimidazolium bromide as co-functional monomer. The obtained DMIMs were characterized by Fourier transform infrared (FT-IR) and scanning electron microscopy (SEM), and empolyed as the special sorbent of solid-phase extraction for isolation of clenbuterol (CLB) and clorprenaline (CLP) from urine sample. The results indicated that the ionic liquid modified polymers were monodispersed microspheres and had high selectivity and adsorbability to CLB and CLP, and the matrix interferences could be efficiently eliminated from the samples. Meanwhile, the effect of template leakage of DMIMs on quantitative analysis was avoided. Compared with other commercial sorbents (HLB, PCX, C18 and SCX), the DMIMs exhibited higher affinity and purification ability to CLP and CLB. Under the optimized conditions, good linearity was observed in a range of 0.90-400?gL(-1) (r(2)=0.9999) with LOD of 0.19 and 0.070?gL(-1) for CLP and CLB, respectively. The recoveries at three spiked levels were ranged from 93.3% to 106% with RSD?5.6% (n=3). PMID:23659982

Yan, Hongyuan; Liu, Suting; Gao, Mengmeng; Sun, Ning

2013-04-17

 
 
 
 
281

Ionic liquids modified dummy molecularly imprinted microspheres as solid phase extraction materials for the determination of clenbuterol and clorprenaline in urine.  

UK PubMed Central (United Kingdom)

New ionic liquid modified dummy molecularly imprinted microspheres (DMIMs) were synthesized by aqueous suspension polymerization using phenylephrine as dummy template and 1-allyl-3-ethylimidazolium bromide as co-functional monomer. The obtained DMIMs were characterized by Fourier transform infrared (FT-IR) and scanning electron microscopy (SEM), and empolyed as the special sorbent of solid-phase extraction for isolation of clenbuterol (CLB) and clorprenaline (CLP) from urine sample. The results indicated that the ionic liquid modified polymers were monodispersed microspheres and had high selectivity and adsorbability to CLB and CLP, and the matrix interferences could be efficiently eliminated from the samples. Meanwhile, the effect of template leakage of DMIMs on quantitative analysis was avoided. Compared with other commercial sorbents (HLB, PCX, C18 and SCX), the DMIMs exhibited higher affinity and purification ability to CLP and CLB. Under the optimized conditions, good linearity was observed in a range of 0.90-400?gL(-1) (r(2)=0.9999) with LOD of 0.19 and 0.070?gL(-1) for CLP and CLB, respectively. The recoveries at three spiked levels were ranged from 93.3% to 106% with RSD?5.6% (n=3).

Yan H; Liu S; Gao M; Sun N

2013-06-01

282

Quantification of free and esterified sterols in Portuguese olive oils by solid-phase extraction and gas chromatography-mass spectrometry.  

Science.gov (United States)

A simple and accurate method based on solid-phase extraction (SPE), transesterification and gas chromatography-mass spectrometry (GC-MS) was developed for the quantitative analysis of free and esterified sterols of olive oil. In order to achieve better separation of esterified and free sterols, silica and alumina SPE adsorbents were tested. Separations by silica provided more reproducible results. The transesterification of both sterol fractions was found to be more user friendly than saponification as a method to liberate the sterols from the respective esters. The free sterols were then silylated with N,O-bis-trimethylsilyltrifluoroacetamide (BSTFA) with 1% of trimethylchlorosilane (TMCS). The most favourable conditions for exploitation of this reagent were established. The optimized methodology was suitable for evaluation of free and esterified sterols in Protected Designation of Origin (PDO) olive oils and monovarietal olive oils with different maturation indices. The prevailing phytosterols in all olive oils were beta-sitosterol and campesterol. The free sterols predominated, although they seemed to decrease with the maturation of the olive fruits. PMID:16860809

Cunha, Sara S; Fernandes, José O; Oliveira, M Beatriz P P

2006-07-24

283

Determination of alternariol in tomato paste using solid phase extraction and high-performance liquid chromatography with fluorescence detection.  

UK PubMed Central (United Kingdom)

Alternaria spp. produce a wide variety of toxic metabolites with different chemical structures. Tomato products have been considered a likely source of Alternaria toxins in the human diet because Alternaria is an important spoilage mold of tomatoes. A new method for the determination of these mycotoxins in tomato paste, involving solid phase cartridges for extraction before HPLC fluorescence detection with a reversed phase column and isocratic elution, was developed. The method was demonstrated to be linear in the range 5.2-196 ppb of alternariol (AOH) in tomato paste. Good recoveries were obtained for AOH at all levels assayed (minimum 77.2%). The detection limit of the AOH toxin in real samples of tomato paste was low, 1.93 ppb. The precision of the method was demonstrated with a good repeatability (RSD = 2.98%) and reproducibility (RSD = 9.35%).

Fente CA; Jaimez J; Vázquez BI; Franco CM; Cepeda A

1998-11-01

284

Determination of alternariol in tomato paste using solid phase extraction and high-performance liquid chromatography with fluorescence detection.  

Science.gov (United States)

Alternaria spp. produce a wide variety of toxic metabolites with different chemical structures. Tomato products have been considered a likely source of Alternaria toxins in the human diet because Alternaria is an important spoilage mold of tomatoes. A new method for the determination of these mycotoxins in tomato paste, involving solid phase cartridges for extraction before HPLC fluorescence detection with a reversed phase column and isocratic elution, was developed. The method was demonstrated to be linear in the range 5.2-196 ppb of alternariol (AOH) in tomato paste. Good recoveries were obtained for AOH at all levels assayed (minimum 77.2%). The detection limit of the AOH toxin in real samples of tomato paste was low, 1.93 ppb. The precision of the method was demonstrated with a good repeatability (RSD = 2.98%) and reproducibility (RSD = 9.35%). PMID:10396802

Fente, C A; Jaimez, J; Vázquez, B I; Franco, C M; Cepeda, A

1998-11-01

285

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

Scientific Electronic Library Online (English)

Full Text Available 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 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 ( (more) 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.

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

2012-01-01

286

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

2012-01-01

287

Validation of antibiotics in catfish by on-line solid phase extraction coupled to liquid chromatography tandem mass spectrometry  

UK PubMed Central (United Kingdom)

For the first time automated on-line solid phase extraction coupled to liquid chromatography tandem mass spectrometry was developed for the simultaneous determination of 13 antibiotics (sulfonamides and tetracyclines) in catfish. The method proposed was validated according to Commission Decision 2002/657/EC, showing good linearity between 2 and 350?gkg?1, high recovery (80–99%) and reproducibility (13–20%) values, lower detection limits than 0.1?gkg?1, and quantification limits under 2.4?gkg?1 (between 39 and 84 times lower than the MRL fixed by the EU). Moreover, the proposed method was also used to determine sulfonamides and tetracyclines in 16 out of 107 samples, all previously analysed by microbiological screening that gave positive results. Five out of 13 antibiotics were found, having tetracycline the higher occurrence (10 samples); in all cases the concentrations were lower than the MRL established.

Hurtado de Mendoza J; Maggi L; Bonetto L; Rodríguez Carmena B; Lezana A; Mocholí FA; Carmona M

2012-09-01

288

Validation of antibiotics in catfish by on-line solid phase extraction coupled to liquid chromatography tandem mass spectrometry.  

UK PubMed Central (United Kingdom)

For the first time automated on-line solid phase extraction coupled to liquid chromatography tandem mass spectrometry was developed for the simultaneous determination of 13 antibiotics (sulfonamides and tetracyclines) in catfish. The method proposed was validated according to Commission Decision 2002/657/EC, showing good linearity between 2 and 350 ?g kg(-1), high recovery (80-99%) and reproducibility (13-20%) values, lower detection limits than 0.1 ?g kg(-1), and quantification limits under 2.4 ?g kg(-1) (between 39 and 84 times lower than the MRL fixed by the EU). Moreover, the proposed method was also used to determine sulfonamides and tetracyclines in 16 out of 107 samples, all previously analysed by microbiological screening that gave positive results. Five out of 13 antibiotics were found, having tetracycline the higher occurrence (10 samples); in all cases the concentrations were lower than the MRL established.

Hurtado de Mendoza J; Maggi L; Bonetto L; Rodríguez Carmena B; Lezana A; Mocholí FA; Carmona M

2012-09-01

289

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

UK PubMed Central (United Kingdom)

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.

Wu S; Mei J

2011-03-01

290

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.

2005-08-29

291

Tributyltin chloride in water: Solid phase extraction, capillary GC (gas chromatography) separation and EC (electron capture) detection  

Energy Technology Data Exchange (ETDEWEB)

A new procedure for determining trace levels of tributyltin chloride (Bu/sub 3/SnCl) present in seawater, without resorting to derivatization, has been developed. The stepwise approach involves: (1) solid phase extraction of Bu/sub 3/SnCl from 100 ml of water using 100 mg of C-18 bonded porous silica; (2) elution with HCl treated ethyl acetate to collect 50 ..mu..l of the eluate; (3) on-column injection of 1 ..mu..l of the eluate and separation on a 15 m DB-5 fused silica capillary column; and (4) detection of pg quantities of Bu/sub 3/SnCl by electron capture. All steps are amenable to automation allowing for low cost determinations of Bu/sub 3/SnCl and possibly other organotin compounds. Background and stability problems with both bonded porous and fused silica are described using test data from contrived and harbor water samples.

Junk, G.A.; Richard, J.J.

1986-09-23

292

A rapid HPLC method for monitoring plasma levels of caffeine and theophylline using solid phase extraction columns.  

UK PubMed Central (United Kingdom)

A simple HPLC method for the determination of caffeine and theophylline in plasma is described. Separation of theobromine, paraxanthine, theophylline, beta-hydroxyethyltheophylline and caffeine is obtained using a mobile phase of 1% acetic acid/methanol (83:17, v/v) and a Waters Associates NOVA-PAK C18 column protected by a Guard-PAK precolumn module containing a Guard-PAK CN cartridge. Rapid sample preparation is achieved by solid-phase extraction columns (Bond-Elut C18, 1 mL capacity) which provide excellent recovery values for both drugs. The cost per sample using this approach can be minimised by column regeneration and re-use. Results obtained for theophylline are in good agreement with values determined by other techniques.

Pickard CE; Stewart AD; Hartley R; Lucock MD

1986-07-01

293

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

UK PubMed Central (United Kingdom)

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 TlNO(3). 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 CF; Martins RK; da Silva AR; da Cunha AL; Aucélio RQ

2013-01-01

294

Determination of selamectin in dog plasma by high performance liquid chromatography with automated solid phase extraction and fluorescence detection.  

UK PubMed Central (United Kingdom)

A method is described for the determination of selamectin in dog plasma, using High-Performance Liquid Chromatography (HPLC) with fluorescence detection (excitation and emission wavelengths fixed at 355 and 465 nm, respectively). The fluorescent derivative was obtained by condensation reaction with trifluoroacetic anhydride and N-methylimidazole. The method employs 1 mL plasma samples and gives linear calibration graphs (r = 0.999) over the concentration range studied (0.5-50 ng mL(-1)). Automatic solid phase extraction using the benchmate procedure was used for sample preparation. This method permits the determination of selamectin at levels as low as 0.1 ng mL(-1) and its suitability was demonstrated by a pharmacokinetic study on a dog receiving the therapeutic dose (Spot-on administration).

Sutra JF; Cadiergues MC; Dupuy J; Franc M; Alvinerie M

2001-09-01

295

Cleanup and analysis of sugar phosphates in biological extracts by using solid phase extraction and anion-exchange chromatography with pulsed amperometric detection  

DEFF Research Database (Denmark)

A cleanup method based on anion-exchange solid-phase extraction (SPE) was developed to render biological extracts suitable for the analysis of hexose phosphates with a modified anion-exchange chromatography method and pulsed amperometric detection. The method was applied to cell extracts of Saccharomyces cerevisiae obtained by using cold methanol as quenching agent and chloroform as extraction solvent. It was shown that pretreatment of the cell extract with SPE markedly improved the quality of the liquid chromatography analysis with recoveries of the sugar phosphates close to 100%. Furthermore, the method allowed for sample enrichment and the original extraction procedure could be simplified by implementing SPE early in the extraction protocol. (C) 1998 Academic Press.

Smith, Hans Peter; Cohen, A.

1998-01-01

296

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

2006-10-24

297

Development and validation of a solid-phase extraction-liquid chromatographic method for determination of amoxicillin in plasma.  

Science.gov (United States)

A bioanalytic method for the determination of amoxicillin in plasma by hydrophilic interaction solid-phase extraction and liquid chromatography has been developed and validated. Plasma was precipitated with acetonitrile before samples were loaded onto a zwitterionic hydrophilic interaction liquid chromatography (ZIC-HILIC) solid-phase extraction column. Amoxicillin was analyzed by liquid chromatography on an Aquasil (150 x 4.6 mm) LC column with mobile-phase acetonitrile: phosphate buffer (pH 2.5; 0.1 mol/L) (7:93, v/v) and UV detection at 230 nm. A regression model using 1/concentration weighting was found the most appropriate for quantification. The intraassay precision for plasma was 3.3% at 15.0 microg/mL and 10.9% at 0.200 microg/mL. The interassay precision for plasma was 1.8% at 15.0 microg/mL and 7.5% at 0.200 microg/mL. The total-assay precision for plasma over 4 days using a total of 20 replicates was 13.2%, 5.5%, and 3.8% at 0.200 microg/mL, 3.00 microg/mL, and 15.0 microg/mL, respectively. The lower limit of quantification and the limit of detection were 0.050 microg/mL and 0.025 microg/mL, respectively, for 100 microL plasma. Long-term storage stability studies of amoxicillin in plasma indicate that a temperature of -80 degrees C is necessary to prevent degradation of amoxicillin. PMID:16044109

Lindegårdh, N; Singtoroj, T; Annerberg, A; White, N J; Day, N P J

2005-08-01

298

Development and validation of a solid-phase extraction-liquid chromatographic method for determination of amoxicillin in plasma.  

UK PubMed Central (United Kingdom)

A bioanalytic method for the determination of amoxicillin in plasma by hydrophilic interaction solid-phase extraction and liquid chromatography has been developed and validated. Plasma was precipitated with acetonitrile before samples were loaded onto a zwitterionic hydrophilic interaction liquid chromatography (ZIC-HILIC) solid-phase extraction column. Amoxicillin was analyzed by liquid chromatography on an Aquasil (150 x 4.6 mm) LC column with mobile-phase acetonitrile: phosphate buffer (pH 2.5; 0.1 mol/L) (7:93, v/v) and UV detection at 230 nm. A regression model using 1/concentration weighting was found the most appropriate for quantification. The intraassay precision for plasma was 3.3% at 15.0 microg/mL and 10.9% at 0.200 microg/mL. The interassay precision for plasma was 1.8% at 15.0 microg/mL and 7.5% at 0.200 microg/mL. The total-assay precision for plasma over 4 days using a total of 20 replicates was 13.2%, 5.5%, and 3.8% at 0.200 microg/mL, 3.00 microg/mL, and 15.0 microg/mL, respectively. The lower limit of quantification and the limit of detection were 0.050 microg/mL and 0.025 microg/mL, respectively, for 100 microL plasma. Long-term storage stability studies of amoxicillin in plasma indicate that a temperature of -80 degrees C is necessary to prevent degradation of amoxicillin.

Lindeg?rdh N; Singtoroj T; Annerberg A; White NJ; Day NP

2005-08-01

299

Optimization of ethylenediamine-grafted multiwalled carbon nanotubes for solid-phase extraction of lead cations.  

UK PubMed Central (United Kingdom)

INTRODUCTION: Ethylenediamine-grafted multiwalled carbon nanotubes (MWCNTs-EDA-I and MWCNTs-EDA-II) are optimized and employed to investigate the preconcentration of lead ions (Pb(II)) in trace level. RESULTS: The results show that Pb(II) can be adsorbed quantitatively on the optimized MWCNTs in the range of pH 4-7 and MWCNTs-EDA-I has a higher maximum Pb(II) adsorption capacity (157.19 mg/g) than MWCNTs-EDA-II (89.16 mg/g). The adsorbed Pb(II) can be eluted completely using 5 mL of 1 mol/L HNO(3). DISCUSSION: A new approach using a microcolumn packed with the obtained MWCNTs-EDA-I has been developed for the preconcentration of trace amount of Pb(II). Parameters influencing the preconcentration of Pb(II), such as pH of the sample, sample volume, elution solution, and interfering ions, have been examined and optimized in detail. Under optimum experimental conditions, the limit of detection is 0.30 ng/mL with the enrichment factor of 60. The relative standard deviation (R.S.D) was 2.6% at the 20 ng/mL Pb(II) level. CONCLUSION: The method has been applied for the preconcentration of trace amount of Pb(II) in environmental water samples with satisfying results.

Hu ZJ; Cui Y; Liu S; Yuan Y; Gao HW

2012-05-01

300

High performance liquid chromatography for quantification of gatifloxacin in rat plasma following automated on-line solid phase extraction.  

UK PubMed Central (United Kingdom)

An automated system using on-line solid phase extraction and HPLC with fluorimetric detection was developed and validated for quantification of gatifloxacin in rat plasma. The extraction was carried out using C(18) cartridges (BondElut), with a high extraction yield. After washing, gatifloxacin was eluted from the cartridge with mobile phase onto a C(18) HPLC column. The mobile phase consisted of a mixture of phosphoric acid (2.5mM), methanol, acetonitrile and triethylamine (64.8:15:20:0.2, v/v/v/v, apparent pH(app.) 2.8). All samples and standard solutions were chromatographed at 28 degrees C. The method developed was selective and linear for drug concentrations ranging between 20 and 600 ng/ml. Gatifloxacin recovery ranged from 95.6 to 99.7%, and the limit of quantification was 20 ng/ml. The intra and inter-assay accuracy were up to 94.3%. The precision determined not exceed 5.8% of the CV. High extraction yield up to 95% was obtained. Drug stability in plasma was shown in freezer at -20 degrees C up to 1 month, after three freeze-thaw cycles and for 24h in the autosampler after processing. The assay has been successfully applied to measure gatifloxacin plasma concentrations in pharmacokinetic study in rats.

Tasso L; Dalla Costa T

2007-05-01

 
 
 
 
301

Simultaneous analysis of some club drugs in whole blood using solid phase extraction and gas chromatography-mass spectrometry.  

UK PubMed Central (United Kingdom)

The use of psychoactive substances to improve social relations and increase body energy, in Rave Culture, has raised many legal and health public concerns, both for illicit trade and consumption. Therefore, forensic toxicology plays an important role in this area, mainly linked to the detection and quantitation of these substances, both in vivo and in post-mortem samples. In fact, at the moment, forensic sciences have been under public authorities' scrutiny and critical look, due to the increasing attention of the media and public opinion, always applying for the use of scientific knowledge to help solving forensic cases. However, forensic toxicology results are only reliable to solve legal cases if all the analytical methodologies used are appropriately validated. In this work, a methodology for the extraction and analysis of 7-aminoflunitrazepam, buprenorphine, flunitrazepam, ketamine, methadone, phencyclidine (PCP) and d-propoxyphene was developed for whole blood samples, with solid phase extraction (SPE), using OASIS(®) MCX SPE columns, and gas chromatography coupled to mass spectrometry. The procedure presented here proved to be reliable, specific, selective and sensitive, with good LODs and LOQs and good precision.The adoption of a SPE procedure with an automatic SPE extraction device, allowed an increased level of automation in sample treatment, being contemporarily less time-consuming, increasing productiveness, and allowing good recovery and appropriate selectivity being, also, simple and reproducible. The simultaneous detection and quantitation of all compounds by the same extraction and detection methodology is crucial and has a great potential for forensic toxicology and clinical analysis.

Castro AL; Tarelho S; Silvestre A; Teixeira HM

2012-02-01

302

Solid-phase extraction element based on epoxy polymer monolith for determination of polar organic compounds in aqueous media.  

UK PubMed Central (United Kingdom)

A solid-phase extraction element based on epoxy polymer monolith was fabricated for sorptive enrichment of polar compounds from liquid and gaseous samples. After ultrasonication of the element in an aqueous solution for a given period of time, the thermal desorption (TD) using a pyrolyzer with gas chromatography/mass spectrometry (GC/MS), in which TD temperature was programmed from 50 to 250 °C for the analytes absorbed in the element, was used to evaluate the element for basic extraction performance using the aqueous standard mixtures consisting of compounds having varied polarities such as hexanol, isoamyl acetate, linalool, furfural and decanoic acid, in concentrations ranging from 10 ?g/L to 1 mg/L. Excellent linear relationships were observed for all compounds in the standard mixture, except decanoic acid. In the extraction of beverages such as red wine, the extraction element showed stronger adsorption characteristics for polar compounds such as alcohols and acids than a non-polar polydimethylsiloxane-based element. This feature is derived from the main polymer structure along with hydroxyl and amino groups present in the epoxy-based monolith polymer matrix.

Takahashi T; Odagiri K; Watanabe A; Watanabe C; Kubo T; Hosoya K

2011-10-01

303

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

International Nuclear Information System (INIS)

[en] 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

1987-01-01

304

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

Energy Technology Data Exchange (ETDEWEB)

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 ..cap alpha.. 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.

Korotkevich, I.B.; Kolesnikov, A.A.; Bomshtein, V.E.; Shikhaleeva, N.N.

1987-01-01

305

[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

306

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

2009-01-01

307

Selective trace analysis of sulfonylurea herbicides in water and soil samples based on solid-phase extraction using a molecularly imprinted polymer.  

UK PubMed Central (United Kingdom)

A molecularly imprinted polymer (MIP) was synthesized using the herbicide metsulfuron-methyl (MSM) as a template, 2-(trifluoromethyl)acrylic acid as a functional monomer, divinylbenzene as a cross-linker, and dichloromethane as a porogen. This polymer was used as a solid-phase extraction material for the quantitative enrichment of five sulfonylureas (nicosulfuron, thifensulfuron-methyl, metsulfuron-methyl, sulfometuron-methyl, and chlorsulfuron) in natural water and soil samples and off-line coupled to a reversed-phase HPLC/diode array detection (HPLC/DAD). Washing solvent was optimized in terms of kind and volume for removing the matrix constituents nonspecifically adsorbed on the MIP. It has been shown that the nonspecific binding ability of the sulfonylureas to the polymer largely increased along with increasing the concentration of Ca2+ ions in the water sample, whereas complexation of divalent ions with EDTA eliminated this interference completely. The stability of MIP was tested by consecutive percolation of water sample, and it was shown that the performance of the MIP did not vary even after 200 enrichment and desorption cycles. Recoveries of the five sulfonylureas extracted from 1 L of tap water and surface water samples such as river water and rainwater at a 50 ng/L spike level were not lower than 96%. The recoveries of sulfonylureas extracted from 10-g soil sample at the 50 microg/kg level were in the range of 71-139%. Depending on the particular compound, the limit of detection varied from 2 to 14 ng/L in water and from 5 to 12 microg/kg in soil samples. The MIP was also compared with a commercially available C-18 column and an immunoaffinity support with encapsulated polyclonal anti-MSM antibodies in sol-gel glass.

Zhu QZ; Degelmann P; Niessner R; Knopp D

2002-12-01

308

Selective trace analysis of sulfonylurea herbicides in water and soil samples based on solid-phase extraction using a molecularly imprinted polymer.  

Science.gov (United States)

A molecularly imprinted polymer (MIP) was synthesized using the herbicide metsulfuron-methyl (MSM) as a template, 2-(trifluoromethyl)acrylic acid as a functional monomer, divinylbenzene as a cross-linker, and dichloromethane as a porogen. This polymer was used as a solid-phase extraction material for the quantitative enrichment of five sulfonylureas (nicosulfuron, thifensulfuron-methyl, metsulfuron-methyl, sulfometuron-methyl, and chlorsulfuron) in natural water and soil samples and off-line coupled to a reversed-phase HPLC/diode array detection (HPLC/DAD). Washing solvent was optimized in terms of kind and volume for removing the matrix constituents nonspecifically adsorbed on the MIP. It has been shown that the nonspecific binding ability of the sulfonylureas to the polymer largely increased along with increasing the concentration of Ca2+ ions in the water sample, whereas complexation of divalent ions with EDTA eliminated this interference completely. The stability of MIP was tested by consecutive percolation of water sample, and it was shown that the performance of the MIP did not vary even after 200 enrichment and desorption cycles. Recoveries of the five sulfonylureas extracted from 1 L of tap water and surface water samples such as river water and rainwater at a 50 ng/L spike level were not lower than 96%. The recoveries of sulfonylureas extracted from 10-g soil sample at the 50 microg/kg level were in the range of 71-139%. Depending on the particular compound, the limit of detection varied from 2 to 14 ng/L in water and from 5 to 12 microg/kg in soil samples. The MIP was also compared with a commercially available C-18 column and an immunoaffinity support with encapsulated polyclonal anti-MSM antibodies in sol-gel glass. PMID:12521169

Zhu, Qing-Zhi; Degelmann, Petra; Niessner, Reinhard; Knopp, Dietmar

2002-12-15

309

Optimization of hydrophilic interaction liquid chromatography/mass spectrometry and development of solid-phase extraction for the determination of paralytic shellfish poisoning toxins.  

Science.gov (United States)

The combination of hydrophilic interaction liquid chromatography (HILIC) and liquid chromatography/mass spectrometry (LC/MS) for the determination of paralytic shellfish poisoning (PSP) toxins has been proposed for use in routine monitoring of shellfish. In this study, methods for the detection of multiple PSP toxins [saxitoxin (STX), neosaxitoxin (NEO), decarbamoyl saxitoxin (dcSTX), decarbamoyl neosaxitoxin (dcNEO), gonyautoxins 1-5 (GTX1, GTX2, GTX3, GTX4, GTX5), decarbamoyl gonyautoxins (dcGTX2 and dcGTX3), and the N-sulfocarbamoyl C toxins (C1 and C2)] were optimized using single (MS) and triple quadrupole (MS/MS) instruments. Chromatographic separation of the toxins was achieved by using a TSK-gel Amide-80 analytical column, although superior chromatography was observed through application of a ZIC-HILIC column. Preparative procedures used to clean up shellfish extracts and concentrate PSP toxins prior to analysis were investigated. The capacity of computationally designed polymeric (CDP) materials and HILIC solid-phase extraction (SPE) cartridges to retain highly polar PSP toxins was explored. Three CDP materials and 2 HILIC cartridges were assessed for the extraction of PSP toxins from aqueous solution. Screening of the CDPs showed that all tested polymers adsorbed PSP toxins. A variety of elution procedures were examined, with dilute 0.01% acetic acid providing optimum recovery from a CDP based on 2-(trifluoromethyl)acrylic acid as the monomer. ZIC-HILIC SPE cartridges were superior to the PolyLC equivalent, with recoveries ranging from 70 to 112% (ZIC-HILIC) and 0 to 90% (PolyLC) depending on the PSP toxin. It is proposed that optimized SPE and HILIC-MS methods can be applied for the quantitative determination of PSP toxins in shellfish. PMID:19202798

Turrell, Elizabeth; Stobo, Lesley; Lacaze, Jean-Pierre; Piletsky, Sergey; Piletska, Elena

310

Optimization of hydrophilic interaction liquid chromatography/mass spectrometry and development of solid-phase extraction for the determination of paralytic shellfish poisoning toxins.  

UK PubMed Central (United Kingdom)

The combination of hydrophilic interaction liquid chromatography (HILIC) and liquid chromatography/mass spectrometry (LC/MS) for the determination of paralytic shellfish poisoning (PSP) toxins has been proposed for use in routine monitoring of shellfish. In this study, methods for the detection of multiple PSP toxins [saxitoxin (STX), neosaxitoxin (NEO), decarbamoyl saxitoxin (dcSTX), decarbamoyl neosaxitoxin (dcNEO), gonyautoxins 1-5 (GTX1, GTX2, GTX3, GTX4, GTX5), decarbamoyl gonyautoxins (dcGTX2 and dcGTX3), and the N-sulfocarbamoyl C toxins (C1 and C2)] were optimized using single (MS) and triple quadrupole (MS/MS) instruments. Chromatographic separation of the toxins was achieved by using a TSK-gel Amide-80 analytical column, although superior chromatography was observed through application of a ZIC-HILIC column. Preparative procedures used to clean up shellfish extracts and concentrate PSP toxins prior to analysis were investigated. The capacity of computationally designed polymeric (CDP) materials and HILIC solid-phase extraction (SPE) cartridges to retain highly polar PSP toxins was explored. Three CDP materials and 2 HILIC cartridges were assessed for the extraction of PSP toxins from aqueous solution. Screening of the CDPs showed that all tested polymers adsorbed PSP toxins. A variety of elution procedures were examined, with dilute 0.01% acetic acid providing optimum recovery from a CDP based on 2-(trifluoromethyl)acrylic acid as the monomer. ZIC-HILIC SPE cartridges were superior to the PolyLC equivalent, with recoveries ranging from 70 to 112% (ZIC-HILIC) and 0 to 90% (PolyLC) depending on the PSP toxin. It is proposed that optimized SPE and HILIC-MS methods can be applied for the quantitative determination of PSP toxins in shellfish.

Turrell E; Stobo L; Lacaze JP; Piletsky S; Piletska E

2008-11-01

311

Extraction and analysis of polycyclic aromatic hydrocarbons and benzo[a]pyrene metabolites in microalgae cultures by off-line/on-line methodology based on matrix solid-phase dispersion, solid-phase extraction and high-performance liquid chromatography.  

Science.gov (United States)

This paper describes the development and validation of an analytical methodology to determine the presence of four PAHs: benzo[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene and benzo[a]pyrene in cultures of the green microalgae Selenastrum capricornutum. The metabolites of benzo[a]pyrene (BaP), 4,5-dihydrodiol benzo[a]pyrene, 9,10-dihydrodiol benzo[a]pyrene, 3-hydroxy benzo[a]pyrene and 9-hydroxy benzo[a]pyrene were also included. The methodology consisted of three parts: (1) separation of liquid media from biomass samples by centrifugation of pure cultures, (2) off-line extraction of analytes from biomass by a miniaturized matrix solid phase dispersion (MSPD) method and from liquid media by a solid phase extraction (SPE) method and (3) on-line SPE preconcentration and analysis of the MSPD and SPE extracts, separately, by high performance liquid chromatography with fluorescence detection (HPLC-FD). The off-line/on-line (MSPD/SPE-HPLC-FD) method was validated over a concentration range of 20-200 pg mg(-1) obtaining good linearity (r(2)>0.9912) and precision values measured as relative standard deviation (RSD)0.9913 and RSD<7.36%, recovery values were in the range of 38-74% and LODs ranged from 0.8 to 2.3 pg mL(-1). This methodology was applied to samples from cultures exposed to BaP at 5 ng mL(-1) with different exposure times (0.75, 1.5, 3, 6, 24 and 48 h). The analytical methodology was suitable for measuring the very low amounts of residual BaP and metabolites produced in bioassays. Results showed that some of the metabolites favored by the microalgae are the dihydrodiols. The microalgae cultures were able to decrease the BaP level in the liquid medium below the United States Environmental Protection Agency (USEPA) limit (<0.2 ng mL(-1)). PMID:23031438

Olmos-Espejel, José J; García de Llasera, Martha P; Velasco-Cruz, Marisol

2012-09-16

312

Extraction and analysis of polycyclic aromatic hydrocarbons and benzo[a]pyrene metabolites in microalgae cultures by off-line/on-line methodology based on matrix solid-phase dispersion, solid-phase extraction and high-performance liquid chromatography.  

UK PubMed Central (United Kingdom)

This paper describes the development and validation of an analytical methodology to determine the presence of four PAHs: benzo[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene and benzo[a]pyrene in cultures of the green microalgae Selenastrum capricornutum. The metabolites of benzo[a]pyrene (BaP), 4,5-dihydrodiol benzo[a]pyrene, 9,10-dihydrodiol benzo[a]pyrene, 3-hydroxy benzo[a]pyrene and 9-hydroxy benzo[a]pyrene were also included. The methodology consisted of three parts: (1) separation of liquid media from biomass samples by centrifugation of pure cultures, (2) off-line extraction of analytes from biomass by a miniaturized matrix solid phase dispersion (MSPD) method and from liquid media by a solid phase extraction (SPE) method and (3) on-line SPE preconcentration and analysis of the MSPD and SPE extracts, separately, by high performance liquid chromatography with fluorescence detection (HPLC-FD). The off-line/on-line (MSPD/SPE-HPLC-FD) method was validated over a concentration range of 20-200 pg mg(-1) obtaining good linearity (r(2)>0.9912) and precision values measured as relative standard deviation (RSD)<5%, recovery values were in the range of (40-66%) and the limits of detection (LODs) ranged from 2 to 6.5 pg mg(-1). The off-line/on-line (SPE/SPE-HPLC-FD) method was validated over a concentration range of 5-120 pg mL(-1); r(2)>0.9913 and RSD<7.36%, recovery values were in the range of 38-74% and LODs ranged from 0.8 to 2.3 pg mL(-1). This methodology was applied to samples from cultures exposed to BaP at 5 ng mL(-1) with different exposure times (0.75, 1.5, 3, 6, 24 and 48 h). The analytical methodology was suitable for measuring the very low amounts of residual BaP and metabolites produced in bioassays. Results showed that some of the metabolites favored by the microalgae are the dihydrodiols. The microalgae cultures were able to decrease the BaP level in the liquid medium below the United States Environmental Protection Agency (USEPA) limit (<0.2 ng mL(-1)).

Olmos-Espejel JJ; García de Llasera MP; Velasco-Cruz M

2012-11-01

313

A novel magnetic poly(aniline-naphthylamine)-based nanocomposite for micro solid phase extraction of rhodamine B.  

UK PubMed Central (United Kingdom)

A novel Fe3O4-poly(aniline-naphthylamine)-based nanocomposite was synthesized by chemical oxidative polymerization process as a magnetic sorbent for micro solid phase extraction. The scanning electron microscopy images of the synthesized nanocomposite revealed that the copolymer posses a porous structure with diameters less than 50nm. The extraction efficiency of this sorbent was examined by isolation of rhodamine B, a mutagenic and carcinogenic dye, from aquatic media in dispersion mode. Among different synthesized polymers, Fe3O4/poly(aniline-naphthylamine) nanocomposite showed a prominent efficiency. Parameters including the desorption solvent, amount of sorbent, desorption time, sample pH, ionic strength, extraction time and stirring rate were optimized. Under the optimum condition, a linear spiked calibration curve in the range of 0.35-5.00?gL(-1) with R(2)=0.9991 was obtained. The limits of detection (3Sb) and limits of quantification (10Sb) of the method were 0.10?gL(-1) and 0.35?gL(-1) (n=3), respectively. The relative standard deviation for water sample with 0.5?gL(-1) of RhB was 4.2% (n=5) and the absolute recovery was 92%. The method was applied for the determination of rhodamine B in dishwashing foam, dishwashing liquid, shampoo, pencil, matches tips and eye shadows samples and the relative recovery percentage were in the range of 94-99%.

Bagheri H; Daliri R; Roostaie A

2013-09-01

314

Capillary electrophoresis with amperometric detection of curcumin in Chinese herbal medicine pretreated by solid-phase extraction.  

UK PubMed Central (United Kingdom)

In the present study, curcumin from Chinese herbal medicine turmeric was determined by capillary electrophoresis with amperometric detection (CE-AD) pretreated by a self-designed, simple, inexpensive solid-phase extraction (SPE) cartridge based on the material of tributyl phosphate resin. An average concentration factor of 9 with the recovery of > 80% was achieved when applied to the analysis of curcumin in extracts of tumeric. Under the optimized CE-AD conditions: a running buffer composed of 15 mM phosphate buffer at a pH 9.7, separation voltage at 16 kV, injection for 6 s at 9 kV and detection at 1.20 V, CE-AD with SPE exhibited low detection limit as 3 x 10(-8) mol/l (S/N = 3), high efficiency of 1.0 x 10(5) N, linear range of 7 x 10(-4) -3 x 10(-6) mol/l (r = 0.9986) for curcumin extracted from light petroleum. The method developed resulted in enhancement of the detection sensitivity and reduction of interference from sample matrix in complicated samples and exhibited the potential application for routine analysis, especially in food, because a relatively complete process of sample treatment and analysis was described.

Sun X; Gao C; Cao W; Yang X; Wang E

2002-07-01

315

Capillary electrophoresis with amperometric detection of curcumin in Chinese herbal medicine pretreated by solid-phase extraction.  

Science.gov (United States)

In the present study, curcumin from Chinese herbal medicine turmeric was determined by capillary electrophoresis with amperometric detection (CE-AD) pretreated by a self-designed, simple, inexpensive solid-phase extraction (SPE) cartridge based on the material of tributyl phosphate resin. An average concentration factor of 9 with the recovery of > 80% was achieved when applied to the analysis of curcumin in extracts of tumeric. Under the optimized CE-AD conditions: a running buffer composed of 15 mM phosphate buffer at a pH 9.7, separation voltage at 16 kV, injection for 6 s at 9 kV and detection at 1.20 V, CE-AD with SPE exhibited low detection limit as 3 x 10(-8) mol/l (S/N = 3), high efficiency of 1.0 x 10(5) N, linear range of 7 x 10(-4) -3 x 10(-6) mol/l (r = 0.9986) for curcumin extracted from light petroleum. The method developed resulted in enhancement of the detection sensitivity and reduction of interference from sample matrix in complicated samples and exhibited the potential application for routine analysis, especially in food, because a relatively complete process of sample treatment and analysis was described. PMID:12198956

Sun, Xiuhua; Gao, Changlu; Cao, Weidong; Yang, Xiurong; Wang, Erkang

2002-07-12

316

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.

Nannan Chen; Hongbo Gao; Nengsheng Ye; Qiding Zhong; Zhenghe Xiong; Xuexin Gu

2012-01-01

317

A novel magnetic poly(aniline-naphthylamine)-based nanocomposite for micro solid phase extraction of rhodamine B.  

Science.gov (United States)

A novel Fe3O4-poly(aniline-naphthylamine)-based nanocomposite was synthesized by chemical oxidative polymerization process as a magnetic sorbent for micro solid phase extraction. The scanning electron microscopy images of the synthesized nanocomposite revealed that the copolymer posses a porous structure with diameters less than 50nm. The extraction efficiency of this sorbent was examined by isolation of rhodamine B, a mutagenic and carcinogenic dye, from aquatic media in dispersion mode. Among different synthesized polymers, Fe3O4/poly(aniline-naphthylamine) nanocomposite showed a prominent efficiency. Parameters including the desorption solvent, amount of sorbent, desorption time, sample pH, ionic strength, extraction time and stirring rate were optimized. Under the optimum condition, a linear spiked calibration curve in the range of 0.35-5.00?gL(-1) with R(2)=0.9991 was obtained. The limits of detection (3Sb) and limits of quantification (10Sb) of the method were 0.10?gL(-1) and 0.35?gL(-1) (n=3), respectively. The relative standard deviation for water sample with 0.5?gL(-1) of RhB was 4.2% (n=5) and the absolute recovery was 92%. The method was applied for the determination of rhodamine B in dishwashing foam, dishwashing liquid, shampoo, pencil, matches tips and eye shadows samples and the relative recovery percentage were in the range of 94-99%. PMID:23972973

Bagheri, Habib; Daliri, Rasoul; Roostaie, Ali

2013-08-02

318

Fast and selective extraction of chloramphenicol from soil by matrix solid-phase dispersion using molecularly imprinted polymer as dispersant.  

UK PubMed Central (United Kingdom)

The molecularly imprinted polymer (MIP) was synthesized and used as dispersant of matrix solid-phase dispersion (MSPD) for the extraction of chloramphenicol (CAP) in soil samples. The satisfactory recovery of CAP was obtained by the optimized extraction conditions: 1:2 as the ratio of sample to MIPs; 5?min as the dispersion time; 30% aqueous methanol as washing solvent and methanol as elution solvent. The CAP extracted from soil was determined by LC-MS/MS. The slight ion suppression phenomenon was observed for the CAP when the sample was cleaned up by MSPD with MIP as dispersant, when compared with C18 as MSPD dispersant, which caused significant ion suppression. LOD of CAP is 4.1?ng/g. RSDs of intra- and inter-day tests ranging from 3.1 to 6.2% and from 3.9 to 8.3% are obtained. At all three fortified levels (20, 100 and 500?ng/g), recoveries of CAP are in the range of 86.9-92.6%. The effect of ageing time of spiked soil sample on the CAP recovery was examined. The CAP recovery decreased from 91.0 to 36.9% when the ageing time changed from 1 day to 4?wk.

Wang T; Tong J; Sun M; Chen L

2011-06-01

319

Fast and selective extraction of chloramphenicol from soil by matrix solid-phase dispersion using molecularly imprinted polymer as dispersant.  

Science.gov (United States)

The molecularly imprinted polymer (MIP) was synthesized and used as dispersant of matrix solid-phase dispersion (MSPD) for the extraction of chloramphenicol (CAP) in soil samples. The satisfactory recovery of CAP was obtained by the optimized extraction conditions: 1:2 as the ratio of sample to MIPs; 5?min as the dispersion time; 30% aqueous methanol as washing solvent and methanol as elution solvent. The CAP extracted from soil was determined by LC-MS/MS. The slight ion suppression phenomenon was observed for the CAP when the sample was cleaned up by MSPD with MIP as dispersant, when compared with C18 as MSPD dispersant, which caused significant ion suppression. LOD of CAP is 4.1?ng/g. RSDs of intra- and inter-day tests ranging from 3.1 to 6.2% and from 3.9 to 8.3% are obtained. At all three fortified levels (20, 100 and 500?ng/g), recoveries of CAP are in the range of 86.9-92.6%. The effect of ageing time of spiked soil sample on the CAP recovery was examined. The CAP recovery decreased from 91.0 to 36.9% when the ageing time changed from 1 day to 4?wk. PMID:21674791

Wang, Ting; Tong, Jia; Sun, Mingli; Chen, Ligang

2011-06-14

320

Solid phase extraction and determination of sub-ppb levels of hazardous Hg2+ ions  

International Nuclear Information System (INIS)

A simple, rapid and reliable method has been developed to selectively separate and concentrate ultra trace amounts of mercury(II) ions from aqueous samples for its highly sensitive measurement by cold vapor atomic absorption spectrometry (CV-AAS). The Hg2+ ions were adsorbed selectively and quantitatively during the passage of aqueous samples through octadecyl silica membrane disks modified by isopropyl 2-[(isopropoxycarbothiolyl)disulfanyl]ethane thioate (IIDE). The retained Hg2+ ions were then stripped from the disk with minimal amounts of 0.5 M hydrobromic acid (two 8 ml portions) as eluent, and determined by CV-AAS. The break-through volume of the method is greater than 3000 ml, which results in enrichment factors >150. Maximum capacity of the membrane disks modified with 10 mg of the ligand was found to be 350 ± 30 ?g of mercury(II), and the limit of detection is 0.005 ng ml-1. The effect of various cationic interferences on the recovery of mercury in binary mixtures was studied. The method was applied to the recovery of Hg2+ ions from different synthetic and tap water samples, as well as the determination of mercury in human hair samples.

2005-01-31

 
 
 
 
321

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

322

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

323

A sensitive method for determining total vanadium in water samples using colorimetric-solid-phase extraction-fiber optic reflectance spectroscopy  

International Nuclear Information System (INIS)

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 (H2O2). 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 ?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-1 and a detection limit as low as 0.01 mg L-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%.

2009-12-30

324

Determination of Phthalates Released from Paper Packaging Materials by Solid-Phase Extraction-High-Performance Liquid Chromatography.  

UK PubMed Central (United Kingdom)

A solid phase extraction (SPE) high-performance liquid chromatography (HPLC) method was developed for the simultaneous determination of 10 phthalic acid esters (dimethyl phthalate, diethyl phthalate, dipropyl phthalate, benzylbutyl phthalate, diisobutyl phthalate, dicyclohexyl phthalate, diamyl phthalate, di-n-hexyl phthalate, di-n-octyl phthalate and di-2-ethylhexyl phthalate) released from food paper packaging materials. The use of distilled water, 3% acetic acid (w/v), 10% ethanol (v/v) and 95% ethanol (v/v) instead of the different types of food simulated the migration of 10 phthalic acid esters from food paper packaging materials; the phthalic acid esters in four food simulants were enriched and purified by a C18 SPE column and nitrogen blowing, and quantified by HPLC with a diode array detector. The chromatographic conditions and extraction conditions were optimized and all 10 of the phthalate acid esters had a maximum absorbance at 224 nm. The method showed limitations of detection in the range of 6.0-23.8 ng/mL the correlation coefficients were greater than 0.9999 in all cases, recovery values ranged between 71.27 and 106.97% at spiking levels of 30, 60 and 90 ng/mL and relative standard deviation values ranged from 0.86 to 8.00%. The method was considered to be simple, fast and reliable for a study on the migration of these 10 phthalic acid esters from food paper packaging materials into food.

Gao X; Yang B; Tang Z; Luo X; Wang F; Xu H; Cai X

2013-05-01

325

Molecularly imprinted polymer as sorbent in micro-solid phase extraction of ochratoxin A in coffee, grape juice and urine.  

UK PubMed Central (United Kingdom)

A simple, environmental friendly and selective sample preparation technique employing porous membrane protected micro-solid phase extraction (?-SPE) loaded with molecularly imprinted polymer (MIP) for the determination of ochratoxin A (OTA) is described. After the extraction, the analyte was desorbed using ultrasonication and was analyzed using high performance liquid chromatography. Under the optimized conditions, the detection limits of OTA for coffee, grape juice and urine were 0.06 ng g(-1), 0.02 and 0.02 ng mL(-1), respectively while the quantification limits were 0.19 ng g(-1), 0.06 and 0.08 ng mL(-1), respectively. The recoveries of OTA from coffee spiked at 1, 25 and 50 ng g(-1), grape juice and urine samples at 1, 25 and 50 ng mL(-1) ranged from 90.6 to 101.5%. The proposed method was applied to thirty-eight samples of coffee, grape juice and urine and the presence of OTA was found in eighteen samples. The levels found, however, were all below the legal limits.

Lee TP; Saad B; Khayoon WS; Salleh B

2012-01-01

326

Valuation of solid phase extraction disks in the determination of pesticide residues in surface and groundwater in Panama  

International Nuclear Information System (INIS)

[en] 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)

1999-01-01

327

Determination of fexofenadine in human plasma using 96-well solid phase extraction and HPLC with tandem mass spectrometric detection.  

Science.gov (United States)

A fast and sensitive HPLC-MS/MS method, utilizing atmospheric pressure chemical ionization, for the determination of fexofenadine in human plasma is described. A deuterated analog, d6-fexofenadine is used as the internal standard (IS). Plasma samples are prepared using 96-well solid phase extraction with plates containing Waters Oasis HLB sorbent. The analytes are chromatographed on a Restek Ultra IBD column (3.2 mm x 50 mm, 3 microm) using a mobile phase consisting of a mixture of 90% acetonitrile and 10% 10 mM ammonium acetate buffer and 0.1% formic acid. Quantitation of the analyte is based on the response from the multiple reaction monitoring of the precursor to product ion pairs for fexofenadine (m/z 502 --> 466) and d6-fexofenadine (m/z 508 --> 472). The assay has been validated over the concentration range of 1-200 ng/ml based on the analysis of 0.5 ml aliquots of plasma. Within-day assay accuracy was between 97 and 102% of nominal, while within-day precision was better than 3.5% CV at all points on the standard curve. Analyte extraction recovery was better than 70% over the range of the standard curve. The method was found to be suitable for the analysis of human plasma samples obtained 24 h following the administration of a single 60 mg dose of fexofenadine. PMID:15193728

Fu, I; Woolf, E J; Matuszewski, B K

2004-06-29

328

Determination of fexofenadine in human plasma using 96-well solid phase extraction and HPLC with tandem mass spectrometric detection.  

UK PubMed Central (United Kingdom)

A fast and sensitive HPLC-MS/MS method, utilizing atmospheric pressure chemical ionization, for the determination of fexofenadine in human plasma is described. A deuterated analog, d6-fexofenadine is used as the internal standard (IS). Plasma samples are prepared using 96-well solid phase extraction with plates containing Waters Oasis HLB sorbent. The analytes are chromatographed on a Restek Ultra IBD column (3.2 mm x 50 mm, 3 microm) using a mobile phase consisting of a mixture of 90% acetonitrile and 10% 10 mM ammonium acetate buffer and 0.1% formic acid. Quantitation of the analyte is based on the response from the multiple reaction monitoring of the precursor to product ion pairs for fexofenadine (m/z 502 --> 466) and d6-fexofenadine (m/z 508 --> 472). The assay has been validated over the concentration range of 1-200 ng/ml based on the analysis of 0.5 ml aliquots of plasma. Within-day assay accuracy was between 97 and 102% of nominal, while within-day precision was better than 3.5% CV at all points on the standard curve. Analyte extraction recovery was better than 70% over the range of the standard curve. The method was found to be suitable for the analysis of human plasma samples obtained 24 h following the administration of a single 60 mg dose of fexofenadine.

Fu I; Woolf EJ; Matuszewski BK

2004-06-01

329

Selective solid-phase extraction of Ni(II) by an ion-imprinted polymer from water samples  

Energy Technology Data Exchange (ETDEWEB)

A new ion-imprinted polymer (IIP) material was synthesized by copolymerization of 4-vinylpyridine as monomer, ethyleneglycoldimethacrylate as crosslinking agent and 2,2'-azobis-sobutyronitrile as initiator in the presence of Ni-dithizone complex. The IIP was used as sorbent in a solid-phase extraction column. The effects of sampling volume, elution conditions, sample pH and sample flow rate on the extraction of Ni ions form water samples were studied. The maximum adsorption capacity and the relative selectivity coefficients of imprinted polymer for Ni(II)/Co(II), Ni(II)/Cu(II) and Ni(II)/Cd(II) were calculated. Compared with non-imprinted polymer particles, the IIP had higher selectivity for Ni(II). The relative selectivity factor ({alpha}{sub r}) values of Ni(II)/Co(II), Ni(II)/Cu(II) and Ni(II)/Cd(II) were 21.6, 54.3, and 22.7, respectively, which are greater than 1. The relative standard deviation of the five replicate determinations of Ni(II) was 3.4%. The detection limit for 150 mL of sample was 1.6 {mu}g L{sup -1} using flame atomic absorption spectrometry. The developed method was successfully applied to the determination of trace nickel in water samples with satisfactory results.

Saraji, Mohammad, E-mail: saraji@cc.iut.ac.ir [Department of Chemistry, Isfahan University of Technology, Isfahan 84154-83111 (Iran, Islamic Republic of); Yousefi, Hamideh [Department of Chemistry, Isfahan University of Technology, Isfahan 84154-83111 (Iran, Islamic Republic of)

2009-08-15

330

Selective solid-phase extraction of Ni(II) by an ion-imprinted polymer from water samples  

International Nuclear Information System (INIS)

A new ion-imprinted polymer (IIP) material was synthesized by copolymerization of 4-vinylpyridine as monomer, ethyleneglycoldimethacrylate as crosslinking agent and 2,2'-azobis-sobutyronitrile as initiator in the presence of Ni-dithizone complex. The IIP was used as sorbent in a solid-phase extraction column. The effects of sampling volume, elution conditions, sample pH and sample flow rate on the extraction of Ni ions form water samples were studied. The maximum adsorption capacity and the relative selectivity coefficients of imprinted polymer for Ni(II)/Co(II), Ni(II)/Cu(II) and Ni(II)/Cd(II) were calculated. Compared with non-imprinted polymer particles, the IIP had higher selectivity for Ni(II). The relative selectivity factor (?r) values of Ni(II)/Co(II), Ni(II)/Cu(II) and Ni(II)/Cd(II) were 21.6, 54.3, and 22.7, respectively, which are greater than 1. The relative standard deviation of the five replicate determinations of Ni(II) was 3.4%. The detection limit for 150 mL of sample was 1.6 ?g L-1 using flame atomic absorption spectrometry. The developed method was successfully applied to the determination of trace nickel in water samples with satisfactory results.

2009-08-15

331

Novel solid phase extraction method for the analysis of 5-nitroimidazoles and metabolites in milk samples by capillary electrophoresis.  

UK PubMed Central (United Kingdom)

A new sample treatment has been developed for the extraction of 5-nitroimidazole (5-NDZ) drugs in milk samples previous to their determination by micellar electrokinetic chromatography (MEKC). Fat removing and protein precipitation were simultaneously carried out by the addition of trichloroacetic acid (TCA) and subsequent centrifugation. Clean-up and off-line concentration were achieved by a novel solid-phase extraction (SPE) method employing mixed cation exchange (MCX) cartridges, obtaining an off-line concentration factor of 18. Analyses were performed in less than 18min employing 20mM phosphate buffer (pH 6.5) and 150mM SDS as background electrolyte (BGE). During the separation procedure a temperature of 20°C and a voltage of 25kV (normal mode) were applied. Due to sweeping effects, an on-line concentration was achieved for all the studied compounds and detection limits lower than 1.8?gL(-1) were obtained. This method has been successfully applied to milk samples of different origins, including raw ewe milk.

Hernández-Mesa M; García-Campaña AM; Cruces-Blanco C

2014-02-01

332

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)

2012-01-01

333

Simultaneous Determination of TetracyclinesResidues in Bovine Milk Samples by Solid Phase Extraction and HPLC-FL Method  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction:Tetracyclines (TCs) are widely used in animal husbandry and their residues in milk may resultinharmful effects on human. The aim of this study was to investigate the presence of TCs residues in various bovine milk samples from local markets of Ardabil, Iran. Methods:One hundred and fourteen pasteurized, sterilized and raw milk samples were collected from markets of Ardabil. Tetracycline, Oxytetracycline and Chlortetracycline (TCs) residues extraction carried out by Solid Phase Extraction method. Determination of TCs residues were performed by high performance liquid chromatography (HPLC) method using Fluorescence detector.Results: The mean of total TCs residues in all samples (114 samples) was 97.6 ±16.9ng/g and that of pasteurized, sterilized and raw milk samples were 87.1 ± 17.7, 112.0 ± 57.3 and 154.0 ± 66.3ng/g respectively. Twenty five point four percent of the all samples, and24.4%, 30% and 28.6% of the pasteurized, sterilized and raw milk samples, respectively had higher TCs residues than the recommended maximum levels (100ng/g). Conclusion:This study indicates the presence of tetracycline residues more than allowed amount. Regulatory authorities should ensure proper withdrawal period before milking the animals and definite supervisions are necessary on application of these drugs.

Mehra Mesgari Abbasi; Hossein Babaei; Masoud Ansarin; Ashraf-o-sadat Nourdadgar; Mahboob Nemati

2011-01-01

334

Preconcentration of Lead in Sugar Samples by Solid Phase Extraction and Its Determination by Flame Atomic Absorption Spectrometry  

Directory of Open Access Journals (Sweden)

Full Text Available A simple and sensitive solid phase extraction utilizing C18 filled cartridges incorporated with dithizone for preconcentration of lead and its subsequent determination by flame atomic absorption spectrometry (FAAS) was developed. Several parameters such as type, concentration and volume of eluent, pH of the sample solution, flow rate of extraction and volume of the sample were evaluated. The effect of a variety of ions on preconcentration and recovery was also investigated. At pH = 7.4 and 1.0 mol?L–1 HCl eluting them, lead ions were recovered quantitatively. The limit of detection (LOD) defined as 3Sbl was determined to be 8.1 ?g L–1 for 500 mL of sample solution and eluted with 5 mL of 1.0 mol?L–1 HCl under optimum conditions. The accuracy and precision (RSD %) of the method were >90% and <10%, respectively. In the end, the proposed method was applied to a number of real sugar samples and the amount of lead was determined by spiking a known concentration of lead into the solution.

Saied Saeed Hosseiny Davarani; Neda Sheijooni-Fumani; Amin Morteza Najarian; Mohammad-Ali Tabatabaei; Siavash Vahidi

2011-01-01

335

Sensitive determination of cadmium in brown rice and spinach by flame atomic absorption spectrometry with solid-phase extraction.  

UK PubMed Central (United Kingdom)

A sensitive flame atomic absorption spectrometry (FAAS) method was developed for the determination of cadmium (Cd) in brown rice and spinach. The method involves extraction with 1?M hydrochloric acid (HCl), followed by a selective pre-concentration by solid-phase extraction (SPE). The pH of the loading sample solution was adjusted to 4.0 for the brown rice and to 5.0 for the spinach. The masking agents, tartrate and citrate, were required for the spinach before pH adjustment. The SPE step achieved a 20-fold enrichment of the sample solution. The limits of quantification (LOQs) were 0.0054?mg?kg?¹ for the brown rice and 0.0022?mg?kg?¹ for the spinach, being more sensitive than those of AOAC Official method 999.10. A single-laboratory validation was performed by testing spiked samples at 0.04 and 0.08?mg?kg?¹ for the brown rice, and 0.02 and 0.04?mg?kg?¹ for the spinach. The average recoveries were 93.3-96.9% with relative standard deviations (RSDs) of 4.1-8.2% for brown rice, and 90.5-91.9% with RSDs of 5.8-10.0% for spinach.

Akamatsu S; Yoshioka N; Mitsuhashi T

2012-01-01

336

Screening of volatile composition of Lavandula hybrida Reverchon II honey using headspace solid-phase microextraction and ultrasonic solvent extraction.  

UK PubMed Central (United Kingdom)

The volatiles of unifloral Lavandula hybrida Reverchon II honey were isolated by means of headspace solid-phase microextraction (HS-SPME) and ultrasonic solvent extraction (USE) and analyzed by gas chromatography and mass spectrometry (GC, GC/MS). A total of 23 compounds were identified in the headspace with hexan-1-ol, hexanal, acetic acid, hotrienol, and 2-phenylacetaldehyde as the principal components. Three solvents of different polarity were used for USE, and a total of 53 compounds were identified. The extracts with pentane/Et(2)O 1 : 2 (v/v) were the most representative for USE method containing the majority of the honey floral origin compounds and potential biomarkers (hexanol, acetic acid, butane-1,3-diol, butane-2,3-diol, benzoic acid, coumarin, and 2-phenylacetic acid). The total number of identified compounds (USE and HS-SPME) was 59. In general, the comparison with volatiles of other lavandin honeys of different geographic origins indicated several similarities, while acetic and formic acids were identified with high percentages in L. hybrida Reverchon II honey.

Jerkovi? I; Marijanovi? Z

2009-03-01

337

Screening of volatile composition of Lavandula hybrida Reverchon II honey using headspace solid-phase microextraction and ultrasonic solvent extraction.  

Science.gov (United States)

The volatiles of unifloral Lavandula hybrida Reverchon II honey were isolated by means of headspace solid-phase microextraction (HS-SPME) and ultrasonic solvent extraction (USE) and analyzed by gas chromatography and mass spectrometry (GC, GC/MS). A total of 23 compounds were identified in the headspace with hexan-1-ol, hexanal, acetic acid, hotrienol, and 2-phenylacetaldehyde as the principal components. Three solvents of different polarity were used for USE, and a total of 53 compounds were identified. The extracts with pentane/Et(2)O 1 : 2 (v/v) were the most representative for USE method containing the majority of the honey floral origin compounds and potential biomarkers (hexanol, acetic acid, butane-1,3-diol, butane-2,3-diol, benzoic acid, coumarin, and 2-phenylacetic acid). The total number of identified compounds (USE and HS-SPME) was 59. In general, the comparison with volatiles of other lavandin honeys of different geographic origins indicated several similarities, while acetic and formic acids were identified with high percentages in L. hybrida Reverchon II honey. PMID:19319870

Jerkovi?, Igor; Marijanovi?, Zvonimir

2009-03-01

338

Use of solid phase extraction for the sequential injection determination of alkaline phosphatase activity in dynamic water systems.  

UK PubMed Central (United Kingdom)

In this work, a solid phase extraction sequential injection methodology for the determination of alkaline phosphatase activity in dynamic water systems was developed. The determination of the enzymatic activity was based on the spectrophotometric detection of a coloured product, p-nitrophenol, at 405 nm. The p-nitrophenol is the product of the catalytic decomposition of p-nitrophenyl phosphate, a non-coloured substrate. Considering the low levels expected in natural waters and exploiting the fact of alkaline phosphatase being a metalloprotein, the enzyme was pre-concentrated in-line using a NTA Superflow resin charged with Zn(2+) ions. The developed sequential injection method enabled a quantification range of 0.044-0.441 unit mL(-1) of enzyme activity with a detection limit of 0.0082 unit mL(-1) enzyme activity (1.9 ?mol L(-1) of pNP) and a determination rate of 17 h(-1). Recovery tests confirmed the accuracy of the developed sequential injection method and it was effectively applied to different natural waters and to plant root extracts.

Santos IC; Mesquita RB; Bordalo AA; Rangel AO

2012-08-01

339

Chemical identification strategies using liquid chromatography-photodiode array-solid-phase extraction-nuclear magnetic resonance/mass spectrometry.  

UK PubMed Central (United Kingdom)

The identification of metabolites in biochemical studies is a major bottleneck in the proliferating field of metabolomics. In particular in plant metabolomics, given the diversity and abundance of endogenous secondary metabolites in plants, the identification of these is not only challenging but also essential to understanding their biological role in the plant, and their value to quality and nutritional attributes as food crops. With the new generation of analytical technologies, in which liquid chromatography (LC)-mass spectrometry (MS) and nuclear magnetic resonance (NMR) play a pioneering role, profiling metabolites in complex extracts is feasible at high throughput. However, the identification of key metabolites remains a limitation given the analytical effort necessary for traditional structural elucidation strategies. The hyphenation of LC-solid phase extraction (SPE)-NMR is a powerful analytical platform for isolating and concentrating metabolites for unequivocal identification by NMR measurements. The combination with LC-MS is a relatively straightforward approach to obtaining all necessary information for structural elucidation. Using this set-up, we could, as an example, readily identify five related glycosylated phenolic acids present in broccoli (Brassica oleracea, group Italica, cv Monaco): 1,2-di-O-E-sinapoyl-?-gentiobiose, 1-O-E-sinapoyl-2-O-E-feruloyl-?-gentiobiose, 1,2-di-O-E-feruloyl-?-gentiobiose, 1,2,2'-tri-O-E-sinapoyl-?-gentiobiose, and 1,2'-di-O-E-sinapoyl-2-O-E-feruloyl-?-gentiobiose.

Moco S; Vervoort J

2012-01-01

340

Determination of triazine herbicides in fruits and vegetables using dispersive solid-phase extraction coupled with LC-MS.  

Science.gov (United States)

A simple, rapid, and sensitive liquid chromatography-mass spectrometry (LC-MS) method was successfully developed for the determination of three chloro-s-triazine herbicides, viz. atrazine, simazine, and propazine, two thiomethyl-s-triazine ones, viz. ametryn and prometryn, and prometon in fruits and vegetables. The instrumental parameters affecting LC separation and MS detection were investigated and the best conditions were selected. Samples were extracted and purified by dispersive solid-phase extraction (dispersive-SPE) with a primary-secondary amine sorbent. Three typical representative samples (luffa, broad bean, and grape) were selected to investigate the effect of different matrices on pesticide recoveries and assay precision after spiking at 0.05 mg/kg. Matrix composition did not interfere significantly with the determination of these pesticides. The recoveries were, with a few exceptions, in the range of 80-110% with relative standard deviations less than 10% (n = 5). In addition, this method was also applied to 21 different kinds of agriculture products collected from the local market, and two of the six triazines could be detected and quantified. PMID:18338404

Ji, Feng; Zhao, Lixia; Yan, Wei; Feng, Qinzhong; Lin, Jin-Ming

2008-04-01

 
 
 
 
341

[Determination of 11 triazole fungicides in fruits using solid phase extraction and gas chromatography-tandem mass spectrometry].  

UK PubMed Central (United Kingdom)

A method was developed and validated for the simultaneous determination of 11 triazole fungicides (tetraconazole, triflumizole, penconazole, hexaconazole, flutriafol, myclobutanil, etuconazole, propiconazole, tebuconazole, epoxiconazole and fluquinconazole) in fruits by gas chromatography-tandem mass spectrometry (GC-MS/MS). The triazole fungicides were extracted from the samples with acetonitrile, then enriched and cleaned-up with solid phase extraction (SPE) on a Carbon/NH2 cartridge (collecting 2 - 10 mL effluent). The detection was carried out by GC-MS/MS in the multiple reaction monitoring (MRM) mode, and the quantification analysis was performed by external standard method. The calibration curves showed good linearity in the range of 10 - 500 microg/L. The correlation coefficients were larger than 0. 994 0. The average recoveries of the 11 fungicides spiked in the fruits at the levels of 10, 50, 100 and 250 microg/kg were between 82.6% and 117.1%, and the relative standard deviations (RSD) were less than 10%. The limits of quantification (S/N = 10) were between 0.8 microg/kg and 3.4 microg/kg. The method possesses low background, high sensitivity, and quantification limits lower than that of the national standard and the values reported in the relevant literature. It can be applied to the routine analysis of the 11 triazole fungicides in fruits.

Li J; Wang Y; Shi J; Jiang L; Yao X; Fang L

2012-03-01

342

[Determination of 11 triazole fungicides in fruits using solid phase extraction and gas chromatography-tandem mass spectrometry].  

Science.gov (United States)

A method was developed and validated for the simultaneous determination of 11 triazole fungicides (tetraconazole, triflumizole, penconazole, hexaconazole, flutriafol, myclobutanil, etuconazole, propiconazole, tebuconazole, epoxiconazole and fluquinconazole) in fruits by gas chromatography-tandem mass spectrometry (GC-MS/MS). The triazole fungicides were extracted from the samples with acetonitrile, then enriched and cleaned-up with solid phase extraction (SPE) on a Carbon/NH2 cartridge (collecting 2 - 10 mL effluent). The detection was carried out by GC-MS/MS in the multiple reaction monitoring (MRM) mode, and the quantification analysis was performed by external standard method. The calibration curves showed good linearity in the range of 10 - 500 microg/L. The correlation coefficients were larger than 0. 994 0. The average recoveries of the 11 fungicides spiked in the fruits at the levels of 10, 50, 100 and 250 microg/kg were between 82.6% and 117.1%, and the relative standard deviations (RSD) were less than 10%. The limits of quantification (S/N = 10) were between 0.8 microg/kg and 3.4 microg/kg. The method possesses low background, high sensitivity, and quantification limits lower than that of the national standard and the values reported in the relevant literature. It can be applied to the routine analysis of the 11 triazole fungicides in fruits. PMID:22715691

Li, Jige; Wang, Yufei; Shi, Jiawei; Jiang, Li; Yao, Xunping; Fang, Lanyun

2012-03-01

343

Group-selective molecularly imprinted polymer solid-phase extraction for the simultaneous determination of six sulfonamides in aquaculture products.  

UK PubMed Central (United Kingdom)

Group-selective molecularly imprinted polymers (MIPs) made from sulfonamides (SAs) using functional monomer methacrylic acid (MAA) were synthesized. The derived molecularly imprinted solid-phase extraction (MISPE) cartridges were developed for the purification and enrichment of aquatic products. The optimum template molecule and the ratio of the functional monomer to the template for obtaining group selectivity to SAs were sulfadimethoxine (SDM) and 4:1, respectively. The MIPs were characterized by Brunauer-Emmett-Teller (BET), scatchard plot, and chromatography analysis, all of which demonstrate better chromatographic behavior and group-selectivity of MIPs for SAs compared with those of corresponding NIPs. The extraction conditions of MISPE for six SAs were optimized; the method precision and accuracy were satisfactory for the fish and shrimp samples at 0.05, 0.1, and 0.2 mg kg(-1) spiked levels. Recoveries ranging from 85.5% to 106.1% (RSD, 1.2-7.0%, n=3) were achieved. The limits of detection (S/N=3) and quantitation (S/N=10) in the shrimp and fish samples were achieved from 8.4 to 10.9 ?g kg(-1) and from 22.4 to 27.7 ?g kg(-1), respectively. Therefore, the obtained MIPs and MISPE can be employed for the enrichment and clean-up of SAs. This paper presents a new analytical method which enables the simultaneous determination and quantification of SAs in aquaculture products.

Shi X; Meng Y; Liu J; Sun A; Li D; Yao C; Lu Y; Chen J

2011-05-01

344

Profiling of soluble neutral oligosaccharides from treated biomass using solid phase extraction and LC-TOF MS.  

UK PubMed Central (United Kingdom)

Thermochemical pretreatments of cellulosic biomass are known to improve cell wall enzymatic digestibility, while simultaneously releasing substantial amounts of soluble oligosaccharides. Profiling of oligosaccharides released during pretreatment yields information essential for choosing glycosyl hydrolases necessary for cost-effective conversion of cellulosic biomass to desired biofuel/biochemical end-products. In this report we present a methodology for profiling of soluble neutral oligosaccharides released from ammonia fiber expansion (AFEX™)-pretreated corn stover. Our methodology employs solid phase extraction (SPE) enrichment of oligosaccharides using porous graphitized carbon (PGC), followed by high performance liquid chromatography (HPLC) separation using a polymeric amine based column and electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS). For structural elucidation on the chromatographic time scale, nonselective multiplexed collision-induced dissociation was performed for quasi-simultaneous acquisition of oligosaccharide molecular and fragment masses in a single analysis. These analyses revealed glucans up to degree of polymerization (DP) 22 without modifications. Additionally, arabinoxylans up to DP=6 were detected in pretreated biomass extracts (post-enzymatic digestion). Cross-ring fragment ion abundances were consistent with assignment of linkages between sugar units in glucans and also xylose backbone in arabinoxylans as 1-4 linkages. Comprehensive profiling of soluble oligosaccharides also demonstrated decreases in levels of acetate esters of arabinoxylan oligosaccharides with concomitant increases in nonacetylated oligosaccharides that were consistent with earlier observations of 85% release of acetate esters by AFEX™ pretreatment.

Vismeh R; Humpula JF; Chundawat SP; Balan V; Dale BE; Jones AD

2013-05-01

345

Determination of nonylphenol and octylphenol in paper by microwave-assisted extraction coupled to headspace solid-phase microextraction and gas chromatography-mass spectrometry  

Digital Repository Infrastructure Vision for European Research (DRIVER)

6 pages, 6 figures.-- PMID: 15782971 [PubMed].-- Printed version published Feb 18, 2005. , A novel and simple method for the determination of active endocrine disrupter compounds (octylphenol OP, and nonylphenol NP) in paper using microwave-assisted extraction (MAE) and headspace solid-phase microextra...

Latorre Fernández, Anna; Lacorte Bruguera, Silvia; Barceló, Damià; Montury, M.

346

Head-Space Solid Phase Micro-extraction Followed by GC/MS Analysis of the Volatile Components in Seeds of Cinnamonum camphora  

Directory of Open Access Journals (Sweden)

Full Text Available The volatile components in seeds of Cinnamomum camphora were analyzed by Solid Phase Micro-extraction (SPME) combined with GC/MS. Twenty four main kinds of volatile compounds, among which the Sesquiterpene (29%), 3-Hexen-2-one (25%) and Monoterpene (10.22%), were separated and analyzed.

Yang Yong; Tao Wenyi

2005-01-01

347

Application of Solid Phase Extraction on Multiwalled Carbon Nanotubes of Some Heavy Metal Ions to Analysis of Skin Whitening Cosmetics Using ICP-AES  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A novel and highly sensitive method for the determination of some heavy metals in skin whitening cosmetics creams using multiwalled carbon nanotubes MWCNTs as solid phase extraction sorbent for the preconcentration of these heavy metals prior to their determination by inductively coupled plasma atom...

ALqadami, Ayoub A.; Abdalla, Mohammad Abulhassan; ALOthman, Zeid A.; Omer, Kamal

348

Solid-phase extraction and reversed-phase high-performance liquid chromatography of the five major alkaloids in Narcissus confusus.  

Science.gov (United States)

A novel, fast and precise method, combining solid-phase extraction and reversed-phase high-performance liquid chromatography is described for the quantitative determination of five alkaloids (galanthamine, N-formylnorgalanthamine, haemanthamine, homolycorine and tazettine/pretazettine) from bulbs of wild Narcissus confusus, a high galanthamine-containing plant species growing in the Iberian Peninsula. PMID:12494748

López, Susana; Bastida, Jaume; Viladomat, Francesc; Codina, Carles

349

Solid-phase extraction and reversed-phase high-performance liquid chromatography of the five major alkaloids in Narcissus confusus.  

UK PubMed Central (United Kingdom)

A novel, fast and precise method, combining solid-phase extraction and reversed-phase high-performance liquid chromatography is described for the quantitative determination of five alkaloids (galanthamine, N-formylnorgalanthamine, haemanthamine, homolycorine and tazettine/pretazettine) from bulbs of wild Narcissus confusus, a high galanthamine-containing plant species growing in the Iberian Peninsula.

López S; Bastida J; Viladomat F; Codina C

2002-11-01

350

Plutonium association with selected solid phases in soils of Rocky Flats, Colorado, using sequential extraction technique  

International Nuclear Information System (INIS)

Plutonium contamination in the soil environs of Rock Flats, CO, has been a potential health risk to the public since the late 1960s. Although the measurement of total activity of Pu-239 + 240 in the soil is important information in appraising this risk, total activity does not provide the information required to characterize the geochemical behavior that affects the transport of Pu from the soil and vadose zone to groundwater. A sequential extraction experiment was conducted to assess the geochemical association of Pu with selected mineralogical and chemical phases of the soil. In the surface horizons, Pu-239 + 240 was primarily associated with the organic C (45-65%), sesquioxides (20-40%), and the residual fraction (10-15%). A small portion of Pu-239+240 was associated with soluble (0.09-0.22%), exchangeable (0.04-0.08%), and carbonates (0.57-7.0%) phases. These results suggest that under the observed pH and oxic conditions, relatively little Pu-239 + 240 is available for geochemically induced transport processes. Uncommon hydrogeochemical conditions were observed during the spring of 1995, which may have facilitated a partial dissolution of sesquioxides followed by desorption of Pu resulting in increased Pu mobility. Systematic errors in the sequential extraction experiment due to postextraction readsorption were evaluated using Np-237 tracer as a surrogate to Pu-239. The results suggested that postextraction readsorption rates were insignificant during the first 30 min after extraction for most chemical and mineralogical phases under study. 50 refs., 2 figs., 5 tabs.

1996-01-01

351

Solid phase extraction for determination of 90Sr in water sample  

International Nuclear Information System (INIS)

We studied the use of an extraction chromatography for determination of 90Sr in samples of contaminated water. The aim of the thesis was to compare selected products from the point of view of the strontium yields and time needed. Three commercial products: 3M Empore Strontium Rad Disk, AnaLig, Sr-Resin and two classical methods: liquid-liquid extraction with tributylphosphate and carbonate co-precipitation (to eliminate interferers) were used for separation of 90Sr. The water sample was used in radiochemical analysis for determination volume activity of 90Sr. A radiochemical strontium yield was traced by using radionuclide 85Sr. Samples were counted over a two week period to monitor the ingrowth of 90Y on TRI CARB LSC counter. Samples were measured using an HPGe detector to find out 85Sr recoveries at 514 keV line and they were counted directly by Cherenkov counting after the growth of 90Y using TriCarb LSC counter after a two- week period (author)

2009-01-01

352

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

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Foi desenvolvido um método altamente sensível, seletivo e rápido para a determinação de mercúrio, a partir da reação rápida de mercúrio(II) com 5-(p-aminobenzilideno)-tiorodanina (ABTR) e posterior extração em fase sólida do quelato colorido, utilizando discos C18. Em pH 3,5 e na presença do emulsificante-OP, ABTR reage com mercúrio(II) para formar um quelato vermelho na razão molar 1:2 (mercúrio:ABTR). O quelato foi enriquecido pela extração em fase s? (more) ?lida com discos C18 e o quelato retido, eluído com dimethyl formamida (DMF). Um fator de enriquecimento na ordem de 50 foi obtido. Em DMF, a absortividade molar do quelato é 1,21´10(5) L mol-1 cm-1 a 545 nm, e a lei de Beer é obedecida no intervalo 0,01~3 µg mL-1 na solução medida. O desvio padrão relativo para onze replicatas a 0,01 µg mL-1 é 1,7%. Este método foi aplicado para a determinação de mercúrio em tabaco e aditivos de tabaco. Bom coeficiente de preconcentração foi encontrado, comparando-se o método proposto com outros similares. Abstract in english 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 C18 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 C18 disks an (more) d 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´10(5) L mol-1 cm-1 at 545 nm, and Beer's law is obeyed in the 0.01~3 µg mL-1 range in the measured solution. The relative standard deviation for eleven sample replicate measurements at the 0.01 µg mL-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.

Yang, Weizhu; Hu, Qun; Ma, Jing; Wang, Liming; Yang, Guangyu; Xie, Gang

2006-10-01

353

Evaluation of BRIT designed prototype 99mTc generator based on solid phase extraction method: in house experience  

International Nuclear Information System (INIS)

Full text: Radiation Medicine Centre is planning to start Centralized radiopharmacy, where 99mTcO4 - activity will be supplied to the other centers. 99Mo-99mTc generators manufactured using fission-produced 99Mo are routinely employed on regular basis at various centers. The 99mTc activity from this generator diminishes with each passing day and it gives shortage of 99mTc activity for many studies at the end of the week. Centralized radiopharmacy will be able to supply a fixed amount of 99mTcO4 - throughout the week to the various centers. For the regular supply of 99mTcO4 - activity conventional and non-conventional methods of 99Mo -99mTc generator systems will be used. We have explored the utility of recently developed BRIT prototype 99Mo -99mTc generator system for its application in Centralized radiopharmacy. The Technique entails the use of solid phase extraction method. The 99mTc was separated from 99Mo by loading 99mTc from 99MoO4 -2 solution on compact solid-phase extraction column and 99mTc activity was eluted with phase-transfer salt TBAB acetonitrile solution. This 99mTc in TBAB was further passed through another column to remove organic phase and TBAB. 99mTc is eluted in normal saline from this column. The eluted 99mTc was purified by using alumina column and sterilized by passing through 0.22 mm membrane filter. The field trial of this system is carried out at RMC, BARC. It was examined with respect to its performance, quality, safety and lacunae from end-user point of view. It was found that the 99mTcO4 - yielded was free of contaminants in 58-75% yield. This first prototype device is not an automated form. The system though effective for elution of 99mTcO4 , required some modifications from utility point of view. We have suggested few modifications in the design of the assembly to facilitate manipulation of the system in hospital radiopharmacy. The modified 99mTc Generator incorporating Peristaltic pumps for liquid transfers and sterilization of eluted 99mTc has now been developed at BRIT for further evaluation. However, for Centralized radiopharmacy fully automated 99mTc Generator would be desirable

2010-01-01

354

Nanobeads-based rapid magnetic solid phase extraction of trace amounts of leuco-malachite green in Chinese major carps.  

UK PubMed Central (United Kingdom)

A proof-of-concept for the use of oleic acid coated magnetic nanobeads (OA-MNBs) for the magnetic solid phase extraction (MSPE) of trace amounts of leuco-malachite green (LMG) from fish samples was developed. The OA-MNBs were prepared by covalently conjugating oleic acid on amino-modified magnetic polystyrene beads. The OA-MNBs were characterized with transmission electron microscopy, Fourier transform infrared spectroscopy and zeta-potential analyzer. The optimized parameters for MSPE with OA-MNBs of LMG from fish muscle involved a combination of pH 10.0 in 10% acetonitrile, 1.5 M sodium chloride as an adsorption solution, and an extraction procedure involving 6 mg OA-MNBs in 18 mL LMG adsorption solution. This was optimized for 0.5 g fish muscles with an incubation period of 10 min using 200 ?L acetonitrile for elution. Using the optimized parameters, the performance of MSPE with OA-MNBs was evaluated by analyzing LMG-spiked fish extracts with liquid chromatography-mass spectrometry (LC-MS/MS) method. The results indicated that recoveries of LMG (from 0.1 to 2 ng/g) ranged from 71.2%-112.6% with relative standard deviations as low as 0.6%. Out of 57 field fish samples, eight LMG positive samples were confirmed using MSPE with OA-MNBs. Compared with traditional liquid-liquid extraction methods, the results showed that MSPE with OA-MNBs had a higher sensitivity for samples with low LMG concentration. Furthermore, the MSPE with OA-MNB took only 40 min to perform without the need for time consuming sample-pretreatment process. Therefore, MSPE with OA-MNBs holds promise for rapid, sensitive, and cost effective screening for LMG in fish samples.

Guo L; Zhang J; Wei H; Lai W; Aguilar ZP; Xu H; Xiong Y

2012-08-01

355

Nanobeads-based rapid magnetic solid phase extraction of trace amounts of leuco-malachite green in Chinese major carps.  

Science.gov (United States)

A proof-of-concept for the use of oleic acid coated magnetic nanobeads (OA-MNBs) for the magnetic solid phase extraction (MSPE) of trace amounts of leuco-malachite green (LMG) from fish samples was developed. The OA-MNBs were prepared by covalently conjugating oleic acid on amino-modified magnetic polystyrene beads. The OA-MNBs were characterized with transmission electron microscopy, Fourier transform infrared spectroscopy and zeta-potential analyzer. The optimized parameters for MSPE with OA-MNBs of LMG from fish muscle involved a combination of pH 10.0 in 10% acetonitrile, 1.5 M sodium chloride as an adsorption solution, and an extraction procedure involving 6 mg OA-MNBs in 18 mL LMG adsorption solution. This was optimized for 0.5 g fish muscles with an incubation period of 10 min using 200 ?L acetonitrile for elution. Using the optimized parameters, the performance of MSPE with OA-MNBs was evaluated by analyzing LMG-spiked fish extracts with liquid chromatography-mass spectrometry (LC-MS/MS) method. The results indicated that recoveries of LMG (from 0.1 to 2 ng/g) ranged from 71.2%-112.6% with relative standard deviations as low as 0.6%. Out of 57 field fish samples, eight LMG positive samples were confirmed using MSPE with OA-MNBs. Compared with traditional liquid-liquid extraction methods, the results showed that MSPE with OA-MNBs had a higher sensitivity for samples with low LMG concentration. Furthermore, the MSPE with OA-MNB took only 40 min to perform without the need for time consuming sample-pretreatment process. Therefore, MSPE with OA-MNBs holds promise for rapid, sensitive, and cost effective screening for LMG in fish samples. PMID:22841089

Guo, Liang; Zhang, Jianwen; Wei, Hua; Lai, Weihua; Aguilar, Zoraida P; Xu, Hengyi; Xiong, Yonghua

2012-05-04

356

Development of a solid-phase extraction-HPLC/single quadrupole MS method for quantification of perfluorochemicals in whole blood.  

Science.gov (United States)

A method for the determination of perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA) simultaneously with 10 closely related perfluorochemicals (PFCs) in human whole blood was developed and validated. PFOS and PFOA are used in various applications, for example, as surfactants and plastic additives, and are subject to environmental and health research due to their persistence. The main part of the data on PFCs in human blood is from serum samples, analyzed mainly by ion pair extraction followed by high-performance liquid chromatography (HPLC) and negative electrospray (ESI) tandem mass spectrometry (MS/MS). The analytical method developed here is suitable for human whole blood and involves solid-phase extraction (SPE) and HPLC negative electrospray single quadrupole mass spectrometry (HPLC/ES-MS). A whole blood aliquot was treated with formic acid and extracted on a octadecyl (C18) SPE column. The PFCs were isolated with methanol, and quantification was performed using single quadrupole mass spectrometry and perfluoroheptanoic acid as internal standard. Validation was performed in the range 0.3-194 ng/mL with recovery between 64 and 112% and limit of detection in the 0.1-0.5 ng/mL range for 11 of the 12 PFCs studied. We applied this method to 20 whole blood samples collected in 1997-2000 from the Swedish population in the ages 24-72. Eleven of the 12 PFCs were detected, and they were quantitatively and qualitatively confirmed using triple quadrupole LC/MS/MS analysis. PFOS, perfluorooctanesulfonamide, perfluorohexanesulfonate, PFOA and perfluorononanoic acid were quantified in all samples. In addition, perfluorohexanoic acid, perfluorodecanoic acid, perfluorodecanesulfonate, perfluoroundecanoic acid, perfluorododecanoic acid, and perfluorotetradecanoic acid were detected in some samples. This study shows that SPE and single quadrupole MS can be applied for extraction and quantification of PFCs in human whole blood, resulting in selectivity and low detection limits. PMID:15679355

Kärrman, Anna; van Bavel, Bert; Järnberg, Ulf; Hardell, Lennart; Lindström, Gunilla

2005-02-01

357

Determination of fungicides in wine by mixed-mode solid phase extraction and liquid chromatography coupled to tandem mass spectrometry.  

UK PubMed Central (United Kingdom)

A novel procedure for the determination of nine selected fungicides (metalaxyl-M, azoxystrobin, myclobutanil, flusilazole, penconazole, tebuconazole, propiconazole, diniconazole and difenoconazole) in wine samples is presented. Sample enrichment and purification is simultaneously performed using mixed-mode, anion exchange and reversed-phase, OASIS MAX solid-phase extraction (SPE) cartridges. Analytes were determined by liquid chromatography coupled to tandem mass spectrometry using atmospheric pressure electrospray ionization (LC-ESI-MS/MS). Parameters affecting the chromatographic determination and the extraction-purification processes were thoroughly investigated. Under optimized conditions, 10 mL of wine were firstly diluted 1:1 with ultrapure water and then passed through the mixed-mode SPE cartridge at a flow of ca. 5 mLmin(-1). After a washing step with 5 mL of an aqueous NH(4)OH solution (5%, w:v), analytes were recovered with just 1 mL of methanol and injected in the LC-MS/MS system without any additional purification. The selective extraction process avoided significant changes in the ionization efficiency for red and white wine extracts in comparison with pure standards in methanol. Performance of the method was good in terms of precision (RSDs<11%) and accuracy (absolute recoveries>72%, determined against pure standards in methanol) reporting method LOQs in the range of 0.01-0.79 ngmL(-1) for target compounds, which are far below the EU maxima residue levels (MRLs) for fungicides in vinification grapes and wine. Several commercial wines from different geographic areas in Spain were analyzed. In most samples, metalaxyl-M and azoxystrobin were found at concentrations up to several ngmL(-1).

Carpinteiro I; Ramil M; Rodríguez I; Cela R

2010-11-01

358

Solid-phase extraction of fluoroquinolones from aqueous samples using a water-compatible stochiometrically imprinted polymer.  

Science.gov (United States)

A novel and simple method for the selective cleanup and preconcentration of fluoroquinolone antibiotics in environmental water samples has been developed using molecularly imprinted polymer solid-phase extraction (MISPE). The molecularly imprinted polymer (MIP) has been prepared using enrofloxacin (ENR) as the template and a stoichiometric quantity of urea-based functional monomer to target the single oxyanionic moieties in the template molecule. The selectivity of the material for enrofloxacin, and structurally related and non-related compounds, has been evaluated using it as stationary phase in liquid chromatography. The novel polymer and the corresponding non-imprinted material (NIP) have been characterised using nitrogen adsorption-desorption isotherms and scanning electron microscopy. Various parameters affecting the extraction efficiency of the materials in the MISPE procedure were evaluated in order to achieve optimal preconcentration and to reduce non-specific interactions. The optimized MISPE/HPLC with fluorescence detection (FLD) method allows direct extraction of the antibiotics from the aqueous samples followed by a selective washing with acetonitrile/water (0.1M 2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid (HEPES) buffer, pH 7.5) (10/90, v/v) and elution with 2% trifluoracetic acid in methanol. Good recoveries and precision, ranging between 66 and 100% (RSD: 2-12%, n=3) for danofloxacin, enrofloxacin, oxolinic acid and flumequine, and moderate recoveries (15-40%, RSD 4-9%, n=3) for norfloxacin, ciprofloxacin, lomefloxacin and sarafloxacin, have been obtained for river water samples fortified with 0.50, 0.75 and 1.0microgL(-1) of all the antibiotics. The method detection limits ranged between 0.01 and 0.30microgL(-1) for all the antibiotics tested, when 100mL water samples were processed. The results demonstrate the applicability of the optimized method for the selective extraction of fluoroquinolones in environmental water samples at the ngL(-1) level. PMID:18790491

Benito-Peña, Elena; Urraca, Javier L; Sellergren, Börje; Moreno-Bondi, María Cruz

2008-09-04

359

Solid phase extraction of Cu(II) as diethyldithiocarbamate (DDTC) complex by polyurethane foam  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a study about the sorption of copper-diethyldithiocarbamate complex onto polyurethane foam (PUF). It was observed that the maximum sorption of Cu(II) (80 or 150 µg L-1) was verified at pH 6.8 in presence of 4.5 x 10-5 mol L-1 DDTC. The shaking time needed to achieve the equilibrium was 40 minutes. From these data, a kinetic characterization was performed by applying three models, which revealed that a film diffusion process was a rate-determining mechanism. Results also indicated that a ether-like solvent extraction was the sorption mechanism. The investigation of many metallic ions as concomitants showed that the sorption by foam is relatively selective and it can be enhanced by using a suitable masking agent or incrementing the foam mass.

Sant'Ana Otoniel D.; Jesuino Luciene S.; Cassella Ricardo J.; Carvalho Marcelo S.; Santelli Ricardo E.

2003-01-01

360

Ofloxacin analysis validation method in human blood plasma (in vitro) using solid-phase extraction HPLC  

Directory of Open Access Journals (Sweden)

Full Text Available Until now, analysis of Ofloxacin in human blood plasma using solidphase extraction (SPE) by HPLC UV detector has not been reported. This study aims to determine the validity of analytical methods in Ofloxacin study in human blood plasma (in vitro) using an HPLC SPE UV detector. Plasma samples were extracted by SPE. Analytes were analyzed using a C18 column (octadecylsilane) 250x4.6 mm, particle size 10 0m, mobile phase 85,5:14,5 v v 0.025 M phosphate buffer (pH 2.2) and acetonitrile with a flow rate of 2 ml/min, detection performed at 294 nm with the internal standard ciprofloxacin. Validated analytical method was based on the parameters: selectivity, accuracy, precision, repeatability, linearity, LOD, LOQ, and the suitability of the system. Validation analysis showed selectivity test Rs>1.5, test repeatability with CV(%) <10%, linearity was obtained in the range of 0.1 to 6 ;g/ml with correlation coefficient (r) from 0.9998 to 0.9999. Based on the area ratio of peak height and a segment of the chromatogram obtained LOD values 0.023 and 0.024 ;g/ml, LOQ value of 0.076 and 0.080 tg/ml, percent accuracy from 94.32 to 100.45% and 97.68 to 101.63%, and precision CV (%) 0.31 to 0.85% and 0.84 to 1.08%. System suitability test results on the retention time, area ratio, and high ratios of peak chromatogram shows the CV(%) <10%. Can be concluded that the analytical methods used have validity in accordance with the requirements.

RESMI MUSTARICHIE; WIWIEK INDRIYAT; IYAN SOPYAN

2011-01-01

 
 
 
 
361

Solid phase extractive preconcentration of some actinide elements using impregnated carbon  

International Nuclear Information System (INIS)

[en] Apricot stone shells were carbonized under certain chemical and thermal conditions. The produced sorbent had been impregnated with different concentrations of oxalic and succinic acids. They were physically characterized and used for preconcentration of U(VI) and Th(IV) from acidified aqueous solutions. Batch equilibrium studies revealed that a quantitative preconcentration could be achieved at pH ?2 for U(VI) and ?1.3 for Th(IV). The equilibrium time was extended up to 24h for U(VI) and 40 min for Th(IV). The modified sorbent showed a superior extractability for U(VI) and Th(IV) with distribution coefficient mean values of 2084 and 7808 mL g-1, respectively. The sorption capacity values are 2.39 and 8.47 mg g-1 for U(VI) and Th(IV) sorption onto apricot stone anchored with oxalic acid and 2.3 and 9.18 mg g-1 for sorbent anchored with succinic acid. Desorption of loaded uranium ions was effectively achieved using 1 M HNO3 while only 0.5 M HNO3 was recommended to release retained thorium ions. (author)

2006-01-01

362

An absorbing microwave micro-solid-phase extraction device used in non-polar solvent microwave-assisted extraction for the determination of organophosphorus pesticides.  

UK PubMed Central (United Kingdom)

A single-step extraction-cleanup method, including microwave-assisted extraction (MAE) and micro-solid-phase extraction (?-SPE), was developed for the extraction of ten organophosphorus pesticides in vegetable and fruit samples. Without adding any polar solvent, only one kind of non-polar solvent (hexane) was used as extraction solvent