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de Oliveira ARM, Cardoso CD, Bonato PS. Stereoselective determination of hydroxychloroquine and its metabolites in human urine by liquid-phase microextraction and CE. Electrophoresis 2007; 28:1081-91. [PMID: 17295421 DOI: 10.1002/elps.200600420] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Liquid-phase microextraction based on polypropylene hollow fibers and CE were applied for the chiral determination of hydroxychloroquine (HCQ) and its metabolites (desethylchloroquine, DCQ; desethylhydroxychloroquine, DHCQ; bisdesethylchloroquine, BDCQ) in human urine. The analytes were extracted from 3 mL of urine spiked with the internal standard (metoprolol) and alkalinized with 250 muL of 2 M NaOH. The analytes were extracted into 1-octanol impregnated in the pores of the hollow fiber, and into an acid acceptor solution inside the hollow fiber. The electrophoretic separations were carried out in 100 mmol/L Tris buffer (pH adjusted to 9.0 with phosphoric acid) containing 1% w/v S-beta-CD and 30 mg/mL HP-beta-CD with a constant voltage of +18 kV. The method was linear over the concentration range of 10-1000 ng/mL for each HCQ stereoisomer and 21-333 ng/mL for each metabolite stereoisomer. Within-day and between-day assay precision and accuracy for the analytes were studied at three concentration levels for each stereoisomer and were lower than 15%. The developed method was applied for the determination of the cumulative urinary excretion of HCQ, DCQ, and DHCQ after oral administration of rac-HCQ to a health volunteer. The results obtained are in agreement with previous literature data.
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52
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Kloskowski A, Chrzanowski W, Pilarczyk M, Namiesnik J. Modern Techniques of Sample Preparation for Determination of Organic Analytes by Gas Chromatography. Crit Rev Anal Chem 2007. [DOI: 10.1080/10408340600976663] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Adam Kloskowski
- a Department of Physical Chemistry , Gdansk University of Technology , Gdansk, Poland
| | - Wojciech Chrzanowski
- a Department of Physical Chemistry , Gdansk University of Technology , Gdansk, Poland
| | - Michał Pilarczyk
- a Department of Physical Chemistry , Gdansk University of Technology , Gdansk, Poland
| | - Jacek Namiesnik
- b Department of Analytical Chemistry , Gdansk University of Technology , Gdansk, Poland
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53
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Lambropoulou DA, Albanis TA. Liquid-phase micro-extraction techniques in pesticide residue analysis. ACTA ACUST UNITED AC 2007; 70:195-228. [PMID: 17161462 DOI: 10.1016/j.jbbm.2006.10.004] [Citation(s) in RCA: 163] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2006] [Accepted: 10/05/2006] [Indexed: 10/24/2022]
Abstract
Modern trends in analytical chemistry are towards the simplification and miniaturization of sample preparation, as well as the minimization of organic solvent used. In view of this aspect, several novel micro-extraction techniques are being developed in order to reduce the analysis step, increase the sample throughput and to improve the quality and the sensitivity of analytical methods. One of the emerging techniques in this area is liquid-phase micro-extraction (LPME). It is a miniaturized implementation of conventional liquid/liquid extraction (LLE) in which only microliters of solvents are used instead of several hundred milliliters in LLE. It is quick, inexpensive and can be automated. In the last few years, LPME has been combined with liquid chromatography (LC) and capillary electrophoresis (CE), besides the generally used coupling to gas chromatography (GC), and has been applied to various matrices, including biological, environmental, and food samples. This work is aimed at providing an overview of the major developments of LPME, coupled with chromatography and CE, as reported in the literature. The paper will focus on the application of the technique to different matrices and the aim is to reveal the panorama of opportunities and to try to indicate the potential of LPME in pesticide analysis. A critical review of the first applications to pesticide analyses is presented in the main part of the manuscript. The optimization of LPME as well as advantages and disadvantages are discussed. It is concluded that, because of its high pre-concentration factor, LPME can be introduced with benefit into water analysis for several pesticide groups. In particular, the application of LPME to non-polar pesticides in environmental analysis appears to be promising. However, similar to other micro-extraction techniques, such as solid phase micro-extraction (SPME), serious limitations still remain when analyzing semi-solid and solid environmental, food or biological matrices and/or highly polar compounds. Thus, other pre-concentration techniques may be a good alternative if an analytical problem cannot be sufficiently dealt with LPME.
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Affiliation(s)
- Dimitra A Lambropoulou
- Laboratory of Environmental Technology, Department of Chemistry, University of Ioannina, Ioannina 45110, Greece
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54
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Samanidou VF, Pechlivanidou AP, Papadoyannis IN. Development of a validated HPLC method for the determination of four 1,4-benzodiazepines in human biological fluids. J Sep Sci 2007; 30:679-87. [PMID: 17461106 DOI: 10.1002/jssc.200600365] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A simple and sensitive HPLC method was developed and validated for the determination of four frequently prescribed 1,4-benzodiazepines: alprazolam (ALP), bromazepam (BRZ), diazepam (DZP), and flunitrazepam (FNZ). Separation was achieved on an Inertsil C8 analytical (250 mm x 4 mm, 5 microm) column, after selective extraction of benzodiazepine drugs from biological matrices by means of SPE. Isocratic elution was performed with a mobile phase consisting of CH3COONH4, 0.05 M CH3OH, and CH3CN (33:57:10 by volume). Quantification was performed at 240 nm with mefenamic acid (6 ng/microL) as the internal standard. DSC-18 Supelco cartridges provided high absolute recoveries (81-115%). The developed method was fully validated in terms of selectivity, linearity, accuracy, precision, stability, and sensitivity. Repeatability (n = 8) and between-day precision (n = 8) revealed RSD <12%. Recoveries from biological samples ranged from 81.2 to 115%. The detection limit of the method was calculated as 3.3-10.2 ng in blood plasma and 2.6-12.6 ng in urine for 20 microL injection volume. The method was applied to spiked biological matrices. Moreover, the method was applied to real samples of urine after an oral administration.
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Affiliation(s)
- Victoria F Samanidou
- Laboratory of Analytical Chemistry, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki, Greece
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55
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Khalili Zanjani MR, Yamini Y, Shariati S, Jönsson JA. A new liquid-phase microextraction method based on solidification of floating organic drop. Anal Chim Acta 2007; 585:286-93. [PMID: 17386676 DOI: 10.1016/j.aca.2006.12.049] [Citation(s) in RCA: 351] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2006] [Revised: 12/20/2006] [Accepted: 12/21/2006] [Indexed: 11/29/2022]
Abstract
In the present study, a new and versatile liquid-phase microextraction method is described. This method requires very simple and cheap apparatus and also a small amount of organic solvent. Eight microliters of 1-undecanol was delivered to the surface of solution containing analytes and solution was stirred for a desired time. Then sample vial was cooled by inserting it into an ice bath for 5 min. The solidified 1-undecanol was transferred into a suitable vial and immediately melted; then, 2 microL of it was injected into a gas chromatograph for analysis. Some polycyclic aromatic hydrocarbons (PAHs) were used as model compounds for developing and evaluating of the method performance. Analysis was carried out by gas chromatography/flame ionization detection (GC/FID). Several factors influencing the microextraction efficiency, such as the nature and volume of organic solvent, the temperature and volume of sample solution, stirring rate and extraction time were investigated and optimized. The applicability of the technique was evaluated by determination of trace amounts of PAHs in environmental samples. Under the optimized conditions, the detection limits (LOD) of the method were in the range of 0.07-1.67 microg L(-1) and relative standard deviations (R.S.D.) for 10 microg L(-1) PAHs were <7%. A good linearity (r(2)>0.995) in a calibration range of 0.25-300.00 microg L(-1) was obtained. After 30 min extraction duration, enrichment factors were in the range of 594-1940. Finally, the proposed method was applied to the determination of trace amounts of PAHs in several real water samples, and satisfactory results were resulted. Since very simple devices were used, this new technique is affordable, efficient, and convenient for extraction and determination of low concentrations of PAHs in water samples.
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56
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Kang X, Pan C, Xu Q, Yao Y, Wang Y, Qi D, Gu Z. The investigation of electrospun polymer nanofibers as a solid-phase extraction sorbent for the determination of trazodone in human plasma. Anal Chim Acta 2007; 587:75-81. [DOI: 10.1016/j.aca.2007.01.021] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2006] [Revised: 01/06/2007] [Accepted: 01/10/2007] [Indexed: 10/23/2022]
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57
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Richoll SM, Colón I. Determination of triphenylphosphine oxide in active pharmaceutical ingredients by hollow-fiber liquid-phase microextraction followed by reversed-phase liquid chromatography. J Chromatogr A 2006; 1127:147-53. [PMID: 16814311 DOI: 10.1016/j.chroma.2006.06.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Revised: 05/26/2006] [Accepted: 06/01/2006] [Indexed: 11/18/2022]
Abstract
A versatile procedure has been developed and validated for the determination of triphenylphosphine oxide (TPPO) at low levels in various active pharmaceutical ingredients (APIs). This procedure incorporates the use of the novel hollow-fiber liquid-phase microextraction (LPME) for the measurement of this potential process-related impurity in aqueous solutions of APIs. A small volume (40 microL) of 1-octanol contained within a hollow polypropylene fiber is used for the extraction of TPPO from low pH aqueous API solutions. More than a 100-fold increase in the TPPO concentration is obtained without additional evaporation of the extract. Experimental parameters of the extraction procedure were investigated to optimize extraction efficiency and minimize sample matrix interference. Using HPLC/UV as the end analysis technique, the procedure was validated for TPPO in the concentration range of 3-16 microg/L with an API present at 1500 mg/L. The versatility of the method was demonstrated by applying the procedure to the analysis of APIs with different molecular structures. This simple LPME procedure is inexpensive and offers appropriate sensitivity for the intended use while providing several advantages over other analysis methods for pharmaceutical samples.
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Affiliation(s)
- Stephen M Richoll
- Analytical R&D, Pfizer Global R&D, Eastern Point Road, Mail Stop 8286-31, Groton, CT 06340, USA.
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58
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Einsle T, Paschke H, Bruns K, Schrader S, Popp P, Moeder M. Membrane-assisted liquid–liquid extraction coupled with gas chromatography–mass spectrometry for determination of selected polycyclic musk compounds and drugs in water samples. J Chromatogr A 2006; 1124:196-204. [PMID: 16870197 DOI: 10.1016/j.chroma.2006.06.093] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2006] [Revised: 06/22/2006] [Accepted: 06/26/2006] [Indexed: 11/28/2022]
Abstract
Selected polycyclic musk compounds and drugs were extracted from water samples by membrane-assisted micro liquid-liquid extraction. The two-phase extraction system consisted of polyethylene membrane bags filled with an organic solvent. Chloroform proved to be most suited as acceptor phase to extract caffeine, Galaxolide, Tonalide, phenazone and carbamazepine from aqueous samples. The compounds were enriched from 50 mL sample into a volume of 500 microL of chloroform. Gas chromatography-mass spectrometry (GC-MS) was applied for analysis. The extraction procedure was optimised in regard to membrane material, extraction time and temperature. The evaluation of the entire analysis protocol found limits of detection that ranged from 20 to 200 ng/L. The linear range of calibration covered one magnitude with standard deviations between 4 and 12%. Method comparison with standard analysis techniques such as solid-phase extraction (SPE) combined with GC-MS as well as LC-MS-MS confirmed this method as an easy and reliable protocol, even for the monitoring of matrix-loaded wastewater. The analysis of real samples established the feasibility of the technique.
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Affiliation(s)
- T Einsle
- UFZ-Centre for Environmental Research Leipzig-Halle in the Helmholtz Association, Department of Analytical Chemistry, Permoserstrasse 15, D-04318 Leipzig, Germany
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59
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Tor A, Aydin ME. Application of liquid-phase microextraction to the analysis of trihalomethanes in water. Anal Chim Acta 2006; 575:138-43. [PMID: 17723583 DOI: 10.1016/j.aca.2006.05.054] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2006] [Revised: 05/15/2006] [Accepted: 05/18/2006] [Indexed: 10/24/2022]
Abstract
A liquid-phase microextraction method for the determination of trihalomethanes (THMs) including chloroform (CHCl3), bromodichloromethane (CHBrCl2), dibromochloromethane (CHBr2Cl) and bromoform (CHBr3) in water samples was developed, with analysis by gas chromatography-electron capture detection (GC-ECD). After the determination of the most suitable solvent and stirring rate for the extraction, several other parameters (solvent drop volume, extraction time and ionic strength of the sample) were optimized using a factorial design to obtain the most relevant variables. The optimized extraction conditions for 5 mL of sample volume in a 10 mL vial were as follows: n-hexane an organic solvent; a solvent drop volume of 2 microL; an extraction time of 5.0 min; a stirring rate of 600 rpm at 25 degrees C; sample ionic strength of 3M sodium chloride. The linear range was 1-75 microg L(-1) for the studied THMs. The limits of detection (LODs) ranged from 0.23 microg L(-1) (for CHBr2Cl) to 0.45 microg L(-1) (for CHCl3). Recoveries of THMs from fortified distilled water were over 70% for a fortification level of 15 microg L(-1), and relative standard deviations of the recoveries were below 5%. Real samples collected from tap water and well water were successfully analyzed using the proposed method. The recovery of spiked water samples was from 73% to 78% with relative standard deviations below 7%.
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Affiliation(s)
- Ali Tor
- Selcuk University, Department of Environmental Engineering, 42031 Campus, Konya, Turkey.
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60
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Chen PS, Huang SD. Coupled two-step microextraction devices with derivatizations to identify hydroxycarbonyls in rain samples by gas chromatography-mass spectrometry. J Chromatogr A 2006; 1118:161-7. [PMID: 16643930 DOI: 10.1016/j.chroma.2006.03.122] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2006] [Revised: 03/31/2006] [Accepted: 03/31/2006] [Indexed: 11/25/2022]
Abstract
Coupling a two-step liquid-phase microextraction (LPME) with O-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine/bis(trimethylsilyl)trifluoroacetamide (PFBHA)/(BSTFA) derivatization was developed to detect hydroxycarbonyls in rainwater samples using gas chromatography-mass spectrometry (GC-MS). LPME provides a fast and inexpensive pre-concentration, and miniaturized extraction to analyze the target compounds rainwater samples. Derivatization techniques offer a clear method to identify target compounds. The hydroxycarbonyls were determined using two-step derivatizations. Dynamic-LPME was applied in the first derivatization, and head-space single drop derivatization was employed in the second reaction. The LODs varied from 0.023 to 4.75 microg/l. The calibration curves were linear for at least two orders of magnitude with R2>or=0.994. The precision was within 6.5-12%, and the relative recoveries in rainwater were more than 89% (the amount added ranged from 0.3 to 15 microg/l). A field sample was found to contain 2.54 microg/l of hydroxyacetone and 0.110 microg/l of 3-hydroxy-2-butanone. Hydroxyacetone was also detected in one of the tested samples at a concentration of 2.39 microg/l.
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Affiliation(s)
- Pai-Shan Chen
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
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61
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Ma M, Kang S, Zhao Q, Chen B, Yao S. Liquid-phase microextraction combined with high-performance liquid chromatography for the determination of local anaesthetics in human urine. J Pharm Biomed Anal 2006; 40:128-35. [PMID: 16076540 DOI: 10.1016/j.jpba.2005.06.023] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2004] [Revised: 06/21/2005] [Accepted: 06/21/2005] [Indexed: 11/23/2022]
Abstract
A simple liquid-phase microextraction (LPME) device combined with high-performance liquid chromatography (HPLC) is presented for the simultaneous analysis of local anaesthetics, lidocaine, bupivacaine, and tetracaine, from human urine sample. An organic solvent showed good compatibility with the mobile phase of the HPLC, o-dibutyl phthalate, was selected. Local anaesthetics are extracted from 6 ml of the feed aqueous solution and human urine sample into a water-immiscible organic solvent suspended at the needle tip of the microsyringe, then the organic solvent was directly introduced to a reversed-phase HPLC system. The kind of the organic extraction solvent, the stirring rate, the pH value of the aqueous feed solution, and the extraction time have been discussed. Under the optimized extraction conditions, high enrichment factors (more than 86.0-fold) and significant sample clean-up for all of studied local anaesthetics were achieved within 30 min. The detection limits (lower than 0.05 microg/ml) were comparable with previously reported gas chromatography methods. This method was applied to specimen of patient who was treated with extradural anaesthesia of lidocaine, bupivacaine, and tetracaine, and revealed that simultaneous determination of above three local anaesthetics in human urine was possible.
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Affiliation(s)
- Ming Ma
- State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082, PR China.
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62
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Sarafraz Yazdi A, Es'haghi Z. Surfactant enhanced liquid-phase microextraction of basic drugs of abuse in hair combined with high performance liquid chromatography. J Chromatogr A 2005; 1094:1-8. [PMID: 16257282 DOI: 10.1016/j.chroma.2005.07.110] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2005] [Revised: 07/17/2005] [Accepted: 07/25/2005] [Indexed: 11/22/2022]
Abstract
The aim of this study was to evaluate the performance of a technique for simultaneous testing of hydrophilic abuse drugs in hair. The analysis of, codeine and methadone in morphine hair included incubation in methanol (5h, 50 degrees C), Surfactant enhanced liquid-phase microextraction (SE-LPME) and HPLC analysis. This study has demonstrated that SE-LPME constitute a real alternative to the other liquid-phase microextraction methods, for pre-concentration and extraction of hydrophilic drugs in biological samples and has shown the advantages of these optimized methodologies over the traditional microextraction techniques. For these drugs recoveries in the range of 57.5-93.7 were obtained from hair. The drugs were enriched by a factor of 61-128 during SE-LPME. Linearity (r2, 0.9982-0.9997) was obtained in the range of 50-500 microg/l for morphine and 10-500 microg/l for codeine and methadone.
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Affiliation(s)
- Ali Sarafraz Yazdi
- Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, Azadi Sq., Mashhad, Khorasan 91775, Iran.
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63
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Colón I, Richoll SM. Determination of methyl and ethyl esters of methanesulfonic, benzenesulfonic and p-toluenesulfonic acids in active pharmaceutical ingredients by solid-phase microextraction (SPME) coupled to GC/SIM-MS. J Pharm Biomed Anal 2005; 39:477-85. [PMID: 15950423 DOI: 10.1016/j.jpba.2005.04.037] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2004] [Revised: 04/07/2005] [Accepted: 04/12/2005] [Indexed: 10/25/2022]
Abstract
The development, optimization and validation of an extraction method for methyl and ethyl esters of various sulfonic acids is presented. The extraction and determination of these esters in active pharmaceutical ingredients (APIs) was accomplished using solid-phase microextraction coupled to GC/MS in the SIM mode. The factors affecting the extraction efficiency are discussed. This method was validated as a limits test and allows the determination of the sulfonic esters at the 5 ppm level in APIs. The method proved to be reproducible (%R.S.D.s less than 6%) and suitable for use with external standard quantitation, and also met basic validation requirements. This method offers numerous advantages over liquid-liquid extraction methods and was also compared to other extraction techniques such as solid-phase extraction (SPE) and liquid-phase microextraction (LPME) also being developed in our laboratories.
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Affiliation(s)
- Ivelisse Colón
- Pfizer Global R and D, Analytical R and D, Eastern Point Road, Mail Stop 4077, Groton, CT 06340, USA.
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64
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Pedersen-Bjergaard S, Rasmussen KE, Brekke A, Ho TS, Halvorsen TG. Liquid-phase microextraction of basic drugs - Selection of extraction mode based on computer calculated solubility data. J Sep Sci 2005; 28:1195-203. [PMID: 16116997 DOI: 10.1002/jssc.200401935] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The extractability of 58 different basic drugs by 3-phase liquid-phase microextraction (LPME) was studied. Extraction recoveries were correlated to solubility data and log D data calculated with a commercial computer program. The basic drugs were extracted from 1.5 mL water samples (pH 13) through approximately 15 microL of dodecyl acetate immobilized within the pores of a porous polypropylene hollow fibre (organic phase), and into 15 microL of 10 mM HCl (acceptor solution) present inside the lumen of the hollow fibre. Compounds with a calculated solubility below 1 mg/mL at pH 2 were poorly recovered and remained principally in the organic phase. For these drugs, 2-phase LPME may be used as an alternative technique, where the aqueous acceptor phase is replaced by an organic solvent. In the solubility range 1-5 mg/mL, most drugs were effectively extracted (recovery >30%), whereas drugs belonging to the solubility range 5-150 mg/mL were all extracted with recoveries above 30% by 3-phase LPME. The hydrophilic nature of most drugs with solubilities above 150 mg/mL prevented them from entering the organic phase, and only those with log D >1.8 were effectively recovered by 3-phase LPME. For drugs with log D < 1.8 (and solubility >150 mg/mL), carrier-mediated LPME was found to be the preferred technique, where an ion-pair reagent (octanoic acid) was added to the sample. In the case of carrier-mediated LPME, the volume of sample was decreased to 100 microL to facilitate rapid extractions. Based on the present work, the extractability of new compounds may easily be predicted to speed up method development. Extractions were also accomplished from plasma samples, where interactions between proteins and the drugs may reduce the extraction recovery. However, dilution of the plasma samples with water and adjustment of pH into the alkaline region effectively suppressed drug-protein interactions for most of the drugs studied.
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65
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Jakubowska N, Polkowska Ż, Namieśnik J, Przyjazny A. Analytical Applications of Membrane Extraction for Biomedical and Environmental Liquid Sample Preparation. Crit Rev Anal Chem 2005. [DOI: 10.1080/10408340500304032] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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66
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Ho TS, Reubsaet JLE, Anthonsen HS, Pedersen-Bjergaard S, Rasmussen KE. Liquid-phase microextraction based on carrier mediated transport combined with liquid chromatography–mass spectrometry. J Chromatogr A 2005; 1072:29-36. [PMID: 15881456 DOI: 10.1016/j.chroma.2004.11.078] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Recently, we demonstrated for the first time liquid-phase microextraction (LPME) of polar drugs based on carrier mediated transport. In this new extraction technique, selected analytes were extracted as ion-pairs from small volumes of biological samples, through a thin layer of a water immiscible organic solvent immobilised in the pores of a porous hollow fibre (liquid membrane), and into a microl volume of an acidic aqueous acceptor solution placed inside the lumen of the hollow fibre. In the current paper, this new extraction technique was combined with liquid chromatography-mass spectrometry (LC-MS) for the first time. Carrier mediated LPME was evaluated for several new model drugs (0.01 <log P< 1.76), the sample clean-up aspects were investigated in detail, and this new extraction technique was fully validated for the first time. Extractions were performed from 50 microl of human plasma samples, which provided sufficient material in combination with LC-MS. Sodium octanoate (50 mM) was added to the sample as carrier, 1-octanol (approximately 15 microl) was used as the liquid membrane in the wall of the hollow fibre, and 50 mM HCl was utilized as acceptor solution in the lumen of the hollow fibre. The addition of carrier to the samples was found to significantly improve extraction recoveries for the polar drugs tested, providing recoveries in the range 16-78%. Validation was accomplished for atenolol and cimetidine. Limits of quantification (S/N = 5) from 50 microl of plasma were 25 and 50 ng/ml for atenolol and cimetidine, respectively. The intra-day precision (R.S.D.) ranged from 7.8 to 17.2% and from 9.5 to 14.1% for atenolol and cimetidine, respectively, and corresponding inter-day precisions (R.S.D.) were within 6.7-1.4% and 7.7-20.3%. The method was linear in the range 25-1500 ng/ml for atenolol (r = 0.992), and 50-3500 ng/ml for cimetidine (r = 0.976). The accuracy of the method was found to be in range 89.1-99.6% and 83.4-86% for atenolol and cimetidine, respectively. The sample clean-up obtained by carrier mediated LPME was excellent, providing a significantly lower back-ground level in total ion current chromatograms by LC-MS as compared to protein precipitation.
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Affiliation(s)
- Tung Si Ho
- School of Pharmacy, University of Oslo, P.O. Box 1068, Blindern, N-0316 Oslo, Norway.
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67
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Jiang X, Oh SY, Lee HK. Dynamic Liquid−Liquid−Liquid Microextraction with Automated Movement of the Acceptor Phase. Anal Chem 2005; 77:1689-95. [PMID: 15762573 DOI: 10.1021/ac040153v] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new dynamic liquid-liquid-liquid microextraction procedure, with the automated movement of acceptor phase (LLLME/AMAP) to facilitate mass transfer, was developed in this study. Four compounds, 3-nitrophenol, 4-nitrophenol, 3,4-dinitrophenol, and 2,4-dichlorophenol, were used as model compounds to be preconcentrated from water samples. The extraction involved filling a 2-cm length of hollow fiber with 4 muL of acceptor solution using a conventional microsyringe, followed by impregnation of the pores of the fiber wall with 1-octanol. The fiber was then immersed in 4 mL of aqueous sample solution. The analytes in the sample solution were extracted into the organic solvent and then back-extracted into the acceptor solution. During extraction, the acceptor phase was repeatedly moved in and out of the hollow fiber channel and the syringe controlled by a syringe pump. Separation and quantitative analyses were then performed by using high-performance liquid chromatography. The results indicated that up to 400-fold enrichment of the analytes could be obtained under the optimized conditions. The enrichment factors were two times those of static liquid-liquid-liquid microextraction. Good repeatabilities (RSD values below 9.30%) were obtained. The calibration linear range was from 10 to 1000 ng/mL with the square of the correlation coefficient (r2) >0.9916. Detection limits were in the range of 0.45-0.98 ng/mL. In addition, as compared with the previously reported dynamic three-phase microextraction in which there was no relative movement between the acceptor and the organic phase (which is not conducive to effective mass transfer), this new method shows much higher extraction efficiency. All these results suggest that this new dynamic LLLME/AMAP technique could be a better alternative to the previous LLLME for the extraction of analytes from aqueous samples.
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Affiliation(s)
- Xianmin Jiang
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Republic of Singapore 117543
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68
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Deng C, Li N, Wang X, Zhang X, Zeng J. Rapid determination of acetone in human blood by derivatization with pentafluorobenzyl hydroxylamine followed by headspace liquid-phase microextraction and gas chromatography/mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2005; 19:647-653. [PMID: 15700238 DOI: 10.1002/rcm.1834] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In the current work, a simple, rapid, accurate and inexpensive method was developed for the determination of acetone in human blood. The proposed method is based on derivatization with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA), followed by headspace liquid-phase microextraction (HS-LPME) and gas chromatography/mass spectrometry (GC/MS). In the present method, acetone in blood samples was derivatized with PFBHA and acetone oxime formed in several seconds. The formed oxime was enriched by HS-LPME using the organic solvent film (OSF) formed in a microsyringe barrel as extraction interface. Finally, the enriched oxime was analyzed by GC/MS in electron ionization (EI) mode. HS-LPME parameters including solvent, syringe plunger withdrawal rate, sampling volume, and extraction cycle were optimized and the method reproducibility, linearity, recovery and detection limit were studied. The proposed method was applied to determination of acetone in diabetes blood and normal blood. It has been shown that derivatization with HS-LPME and GC/MS is an alternative method for determination of the diabetes biomarker, acetone, in blood samples.
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Affiliation(s)
- Chunhui Deng
- Department of Chemistry, Fudan University, Shanghai 200433, China
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69
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Pan HJ, Ho WH. Determination of fungicides in water using liquid phase microextraction and gas chromatography with electron capture detection. Anal Chim Acta 2004. [DOI: 10.1016/j.aca.2004.08.016] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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70
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Hauser B, Schellin M, Popp P. Membrane-Assisted Solvent Extraction of Triazines, Organochlorine, and Organophosphorus Compounds in Complex Samples Combined with Large-Volume Injection-Gas Chromatography/Mass Spectrometric Detection. Anal Chem 2004; 76:6029-38. [PMID: 15481950 DOI: 10.1021/ac0492923] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The performance of the fully automated membrane-assisted solvent extraction was investigated for 47 environmental contaminants (among them 30 organochlorine compounds, 9 organophosphorus compounds, and 7 triazines). The extraction took place in a 20-mL headspace vial filled with the aqueous sample and containing a polypropylene membrane bag with 1 mL of cyclohexane as extractant. This device was handled by a multipurpose sampler, which enabled the sample to be mixed at a defined temperature with subsequent large-volume injection of the organic extract taken out of the membrane bag. After optimization of extraction parameters, the method was validated for the three compound classes, triazines and organochlorine and organophosphorus compounds, using spiked distilled water. Then, the extraction yield of these analytes from several complex samples such as a natural and a synthetic wastewater, a bacterial culture, and orange juice was determined and compared to a conventional liquid-liquid extraction. Furthermore, the possibility of reducing matrix interference by adding salt, methanol, or detergent during membrane-assisted solvent extraction was investigated.
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Affiliation(s)
- Barbara Hauser
- Department of Analytical Chemistry, UFZ Centre for Environmental Research, Permoserstrasse 15, D-04318 Leipzig, Germany
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71
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Basheer C, Lee HK, Obbard JP. Application of liquid-phase microextraction and gas chromatography–mass spectrometry for the determination of polychlorinated biphenyls in blood plasma. J Chromatogr A 2004; 1022:161-9. [PMID: 14753783 DOI: 10.1016/j.chroma.2003.09.043] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
This study investigated the feasibility of applying liquid-phase microextraction combined with gas chromatography-mass spectrometry (GC-MS) to determine polychlorinated biphenyls (PCBs) in blood plasma. An efficient and simple extraction technique has been developed for the enrichment of PCBs from human blood plasma samples using single-step liquid-phase microextraction (LPME) in conjunction with a hollow fibre membrane (HFM). An eight PCB congener mixture was spiked into 2.5 ml of blood plasma, and the solution was then adjusted to pH 10.5 with a salinity of 20% (w/v) prior to making the total volume to 5 ml with ultrapure water. The porous HFM, filled with 3 microl of organic solvent, was then immersed into the solution, which was continuously agitated at 700 rpm for 30 min. Extract (1 microl) containing the pre-concentrated analytes was then injected into a GC-MS without further pre-treatment. Using an optimised extraction procedure, a large enrichment factor of the analytes, i.e. up to 241-fold was achieved in 30 min. The procedure resulted in a relative standard deviation of < 11% (n = 6), and a linear calibration range from 2.5 to 150 microg/l (r > 0.999), and detection limits between 0.07 and 0.94 microg/l, respectively. To demonstrate the feasibility of the procedure, PCB concentrations were determined in actual blood samples collected from the local population in Singapore using the optimised LPME technique.
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Affiliation(s)
- Chanbasha Basheer
- Department of Chemistry, 3 Science Drive 3, National University of Singapore, Singapore 117543, Singapore
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72
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Yan CH, Wu HF. A liquid-phase microextraction method, combining a dual gauge microsyringe with a hollow fiber membrane, for the determination of organochlorine pesticides in aqueous solution by gas chromatography/ion trap mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2004; 18:3015-3018. [PMID: 15536632 DOI: 10.1002/rcm.1722] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A liquid-phase microextraction (LPME) method has been demonstrated for the extraction and determination of organochlorine pesticides (OCPs) in aqueous solution. The method combines a dual gauge microsyringe with a hollow fiber membrane (LPME/DGM-HF) followed by detection by gas chromatography/ion trap mass spectrometry (GC/ITMS). The advantages include speed, low solvent and sample consumption, simplicity and ease of use. The extraction time, solvent selection, salt concentration and sample stirring rate have been investigated in order to optimize extraction efficiency. The viability is evaluated by measuring the linearity and detection limit of the five OCPs in aqueous solution. Detection linearity for the OCPs has been achieved over a range of concentrations between 1 and 500 microg/L (r2 > 0.930), with a detection limit of 0.1 microg/L for each OCP.
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Affiliation(s)
- Chih-Hao Yan
- Department of Chemistry, Tamkang University, Tamsui, Taipei Hsein, 251, Taiwan
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73
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Rasmussen KE, Pedersen-Bjergaard S. Developments in hollow fibre-based, liquid-phase microextraction. Trends Analyt Chem 2004. [DOI: 10.1016/s0165-9936(04)00105-0] [Citation(s) in RCA: 432] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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74
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Wen X, Tu C, Lee HK. Two-Step Liquid−Liquid−Liquid Microextraction of Nonsteroidal Antiinflammatory Drugs in Wastewater. Anal Chem 2003; 76:228-32. [PMID: 14697055 DOI: 10.1021/ac0302354] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A simple and novel two-step liquid-liquid-liquid microextraction technique combined with reversed-phase HPLC has been developed for the determination of the nonsteroidal antiinflammatory drugs ibuprofen and 2-(4-chlorophenoxy)-2-methylpropionic acid in wastewater samples. In the first step, the analytes were extracted from an acidified sample (donor solution) into 1-octanol immobilized in the pores of 10 pieces of polypropylene hollow fiber and further into a basic acceptor phase inside the hollow fiber channels. This first extraction step, using 0.01 M NaOH as the acceptor phase and 0.1 M HCl within the donor phase, had a 100% relative recovery with an enrichment factor of 100-fold. The extract in the first step was then adjusted to acidic condition with HCl. It now represented the donor phase for the second step of the extraction, using a single piece of hollow fiber, with 2 microL of 0.01 M NaOH solution as the acceptor phase. This analyte-enriched acceptor phase was subsequently withdrawn into a microsyringe and directly injected into an HPLC system for analysis. With this two-step microextraction, sensitivity enhancement of >15,000-fold could be obtained. Detection limits of < or =100 ng/L could be achieved for both compounds. The method was applied to the analysis of wastewater.
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Affiliation(s)
- Xiujuan Wen
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Republic of Singapore 117543
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75
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76
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Bjørhovde A, Halvorsen TG, Rasmussen KE, Pedersen-Bjergaard S. Liquid-phase microextraction of drugs from human breast milk. Anal Chim Acta 2003. [DOI: 10.1016/s0003-2670(03)00768-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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77
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Jonsson OB, Nilsson UL. Determination of organophosphate ester plasticisers in blood donor plasma using a new stir-bar assisted microporous membrane liquid-liquid extractor. J Sep Sci 2003. [DOI: 10.1002/jssc.200301491] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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78
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Hou L, Lee HK. Dynamic three-phase microextraction as a sample preparation technique prior to capillary electrophoresis. Anal Chem 2003; 75:2784-9. [PMID: 12948150 DOI: 10.1021/ac020753z] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dynamic three-phase (liquid-liquid-liquid) microextraction was developed for capillary electrophoresis. Four aromatic amines as model compounds were extracted from 4-mL aqueous samples adjusted to basic condition (donor solution) through a small volume of organic solvent impregnated in a hollow fiber, which was held by the needle of a conventional syringe, and retracted into a 5-microL acidic acceptor solution inside the syringe. A renewable organic film and aqueous sample plug were formed inside the hollow fiber with the repeated movement of the syringe plunger enabled by a programmable syringe pump. This is believed to be the first reported instance of a semiautomated dynamic liquid-liquid-liquid microextraction (LLLME) procedure. Following this microextraction, the 5-microL acceptor solution was analyzed by capillary zone electrophoresis (CE). This new technique provided approximately 140-fold enrichment in 20 min. Utilizing 4-chloroaniline as internal standard, dynamic LLLME could provide good reproducibility (<4.0%). In addition, this method allowed the direct transfer of extracted analytes to a CE system for analysis.
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Affiliation(s)
- Li Hou
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Republic of Singapore 117543
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79
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Ho TS, Halvorsen TG, Pedersen-Bjergaard S, Rasmussen KE. Liquid-phase microextraction of hydrophilic drugs by carrier-mediated transport. J Chromatogr A 2003; 998:61-72. [PMID: 12862372 DOI: 10.1016/s0021-9673(03)00634-4] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Basic studies on carrier-mediated transport as a mechanism to extract polar drugs by hollow fibre-based liquid-phase microextraction are presented for the first time. Hydrophilic alkaline drugs with log P (octanol/water partition coefficient) values less than 1 were selected as model substances. Sodium octanoate served as carrier and was added to the sample solution at pH 7 to form hydrophobic ion-pair complexes with the analytes. The ion-pair complexes were extracted into octanol as liquid membrane immobilised in the pores of the hollow fibre. Further extraction into an aqueous acceptor phase inside the lumen of the hollow fibre was facilitated by counter transport of protons from the acceptor solution to the sample solution. Protons from the acceptor solution released the analytes at the liquid membrane-acceptor interface and neutralized the carrier. The acceptor phase was analysed by capillary electrophoresis. The studies show that high extraction recoveries of ionic hydrophilic drugs can be obtained at a sample-acceptor volume ratio of 10. Linear calibration graphs and clean electropherograms indicate that carrier-mediated transport is a promising technique in microextraction of polar drugs from biological matrices.
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Affiliation(s)
- Tung Si Ho
- School of Pharmacy, University of Oslo, P.O. Box 1068 Blindern, N-0316 Oslo, Norway.
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80
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Müller S, Möder M, Schrader S, Popp P. Semi-automated hollow-fibre membrane extraction, a novel enrichment technique for the determination of biologically active compounds in water samples. J Chromatogr A 2003; 985:99-106. [PMID: 12580476 DOI: 10.1016/s0021-9673(02)01803-4] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An automated hollow fibre membrane extraction technique was developed for the GC-MS determination of pharmaceutical and endocrine disrupting compounds in water samples. Enrichment was carried out inside a porous polypropylene hollow fibre membrane, which separated the aqueous and organic phases and regulated the transfer of analytes. n-Octanol placed inside the hollow fibre was used as the acceptor solution. A water-solvent ratio of about 300:1 was used to concentrate the analytes. After 1 hour's extraction of the water sample under magnetic stirring, 1 microl of the n-octanol phase was automatically injected from the hollow fibre into the GC-MS. Development work included examining the influence of different sample matrices, volumes, extraction times and extraction solvents. The detection limits, linearity and standard deviations of the method were determined using drugs such as ibuprofen, phenazone and carbamazepine as well as the endocrine disrupting compounds. technical nonylphenols, bisphenol A, 17alpha-ethinylestradiol and tonalide by way of example.
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Affiliation(s)
- Sabine Müller
- Science Park Permoserstrasse e.V., Permoserstrasse 15, D-04318 Leipzig, Germany.
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81
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New membrane extraction cell for on-line analysis of VOCs or the simultaneous determination of VOCs and phenols in water. Chromatographia 2003. [DOI: 10.1007/bf02492108] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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82
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King S, Meyer JS, Andrews ARJ. Screening method for polycyclic aromatic hydrocarbons in soil using hollow fiber membrane solvent microextraction. J Chromatogr A 2002; 982:201-8. [PMID: 12489876 DOI: 10.1016/s0021-9673(02)01594-7] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A fast, inexpensive screening method for polycyclic aromatic hydrocarbons in soil has been developed. Using hollow fiber membrane solvent microextraction, 8 microl of octane extraction solvent was placed inside a porous, polypropylene fiber. Following an 8 min analyte preconcentration step, 4 microl of extract was injected into a gas chromatograph. Separation was achieved in less than 10 min with a detection limit of 0.13 mg/kg for 2-methylnaphthalene. Results of both spiked and real soil samples are presented.
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Affiliation(s)
- Stephanie King
- Department of Chemistry and Biochemistry, Ohio University, Athens, OH 45701-2979, USA.
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83
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Basheer C, Lee HK, Obbard JP. Determination of organochlorine pesticides in seawater using liquid-phase hollow fibre membrane microextraction and gas chromatography-mass spectrometry. J Chromatogr A 2002; 968:191-9. [PMID: 12236503 DOI: 10.1016/s0021-9673(02)00793-8] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The use of hollow fibre membrane microextraction in analytical chemistry has been increasing as the technique is a simple and efficient method for the extraction of trace organic compounds from environmental matrices. A simple liquid-phase microextraction technique using a hollow fibre membrane in conjunction with gas chromatography-mass spectrometry has been developed for the extraction and analysis of organochlorine pesticides (OCPs), i.e. alpha-hexachlorocyclohexane (BHC), lindane, beta-BHC, heptachlor, aldrin, dieldrin, endrin, endosulfan, p,p'-DDD, p,p'-DDT, endrin aldehyde and methoxychlor, from seawater. The technique requires minimal sample preparation time and solvent consumption, and represents a significant advantage over conventional analytical methods. Optimum extraction conditions have been evaluated with respect to sample pH, salt content and stirring rate, as well as solvent type and extraction time. A high level of detection linearity (coefficient of >0.9995, less than 14% RSD) was obtained for OCPs over a range of analyte concentrations between 5 and 100 microg l(-1), with detection limits in the parts per trillion (ppt) to sub-parts per billion range. Comparison between liquid-phase microextraction with hollow fibre membrane and US Environmental Protection Agency Method 508 showed that the novel method has comparable detection limits of between 0.013 and 0.059 microg l(-1) in seawater.
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Affiliation(s)
- Chanbasha Basheer
- Department of Chemistry, National University of Singapore, Singapore
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84
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Andersen S, Halvorsen TG, Pedersen-Bjergaard S, Rasmussen KE. Liquid-phase microextraction combined with capillary electrophoresis, a promising tool for the determination of chiral drugs in biological matrices. J Chromatogr A 2002; 963:303-12. [PMID: 12187985 DOI: 10.1016/s0021-9673(02)00223-6] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A disposable device for liquid-phase microextraction (LPME) based on porous polypropylene hollow fibres has recently been introduced. In the present paper, LPME was combined with capillary electrophoresis (CE) and the combination was for the first time evaluated for chiral determination of drugs in biological matrices. The chiral antidepressant drug mianserin was selected as model compound. The mianserin enantiomers were extracted from 0.5 ml of plasma added internal standard and made alkaline with 0.25 ml of 2 M NaOH. The unionised analytes were extracted into di-n-hexyl ether impregnated in the pores of the hollow fibre, and into an acidic solution inside the hollow fibre. This resulted in a three-phase system where the extracts were aqueous, and hence directly compatible with the CE system. Efficient sample clean-up was seen and the extraction recovery was 80% for both enantiomers. Discrimination between the enantiomers in the extraction system was not observed. The limit of quantitation (S/N= 10; 12.5 ng/ml for both enantiomers) and the limit of detection (S/N=3; 4 ng/ml for both enantiomers) were below the therapeutic range for mianserin. The method was validated and successfully applied to determine R- and S-mianserin in plasma samples from seven patients treated with mianserin, indicating that LPME-CE is a promising combination for analysis of racemic drugs present in low concentrations in biological matrices.
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85
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Zhao L, Zhu L, Lee HK. Analysis of aromatic amines in water samples by liquid-liquid-liquid microextraction with hollow fibers and high-performance liquid chromatography. J Chromatogr A 2002; 963:239-48. [PMID: 12187976 DOI: 10.1016/s0021-9673(02)00544-7] [Citation(s) in RCA: 152] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Liquid-liquid-liquid microextraction (LLLME) with hollow fibers in high-performance liquid chromatography (HPLC) has been applied as a rapid and sensitive quantitative method for the detection of four aromatic amines (3-nitroaniline, 4-chloroaniline, 4-bromoaniline and 3,4-dichloroaniline) in environmental water samples. The preconcentration procedure was induced by the pH difference inside and outside the hollow fiber. The target compounds were extracted from 4-ml aqueous sample (donor solution, pH approximately 13) through a microfilm of organic solvent (di-n-hexyl ether), immobilized in the pores of a hollow fiber (1.5 cm length x 0.6 mm I.D.), and finally into 4 microl of acid acceptor solution inside the fiber. After a prescribed period of time, the acceptor solution inside the fiber was withdrawn into the microsyringe and directly injected into the HPLC system for analysis. Factors relevant to the extraction procedure were studied. Up to 500-fold enrichment of analytes could be obtained under the optimized conditions (donor solution: 0.1 M sodium hydroxide solution with 20% sodium chloride and 2% acetone; organic phase: di-n-hexyl ether; acceptor solution: 0.5 M hydrochloric acid and 500 mM 18-crown-6 ether; extraction time of 30 min; stirring at 1,000 rev./min). The procedure also served as a sample clean-up step. The influence of humic acid on the extraction efficiency was also investigated, and more than 85% relative recoveries of the analytes at two different concentrations (20 and 100 microg/l) were achieved at various concentration of humic acid. This technique is a low cost, simple and fast approach to the analysis of polar compounds in aqueous samples.
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Affiliation(s)
- Limian Zhao
- Department of Chemistry, National University of Singapore, Singapore
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86
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Ho TS, Pedersen-Bjergaard S, Rasmussen KE. Recovery, enrichment and selectivity in liquid-phase microextraction comparison with conventional liquid-liquid extraction. J Chromatogr A 2002; 963:3-17. [PMID: 12187984 DOI: 10.1016/s0021-9673(02)00215-7] [Citation(s) in RCA: 133] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Mathematical descriptions for extraction recovery and enrichment were applied for liquid-phase microextraction (LPME) and comparison with conventional two- and three-phase liquid-liquid extraction techniques (LLE) was made. The LPME theoretical calculations were verified by experimental determination of actual partition coefficients and by data obtained with LPME in a robust hollow fibre formate. With hollow fibre LPME operated in the two-phase mode, analytes were extracted from 1 to 4 ml aqueous samples into 25-50 microl of an organic solvent present in the pores and in the lumen of the porous hollow fibres. Compared with conventional two-phase LLE, two-phase LPME provided substantially higher enrichments for compounds with relatively large partition coefficients (K(org)/d>500). In contrast, because of the large volume of organic solvent relative to the sample volume, LLE provided high recovery and moderate enrichment even for compounds with relatively low partition coefficients (K(org)/d>5). Thus, two-phase LPME may be used for substantially enhanced extraction selectivity and enrichment of relatively hydrophobic analytes as compared with LLE whereas conventional two-phase LLE is superior for more hydrophilic analytes. Similar results were found for three-phase LPME where analytes where extracted from 1 to 4 ml aqueous samples through approximately 20 microl organic solvent immobilized within the pores of the hollow fibre and into 25 microl of an aqueous acceptor solution inside the lumen of the hollow fibre. The fundamental differences of LPME and LLE were further demonstrated with practical experiments on extraction of the basic drugs promethazine, methadone, and haloperidol from human plasma and urine.
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Affiliation(s)
- Tung Si Ho
- School of Pharmacy, University of Oslo, Norway.
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87
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Hause B, Popp P, Kleine-Benne E. Membrane-assisted solvent extraction of triazines and other semi-volatile contaminants directly coupled to large-volume injection-gas chromatography-mass spectrometric detection. J Chromatogr A 2002; 963:27-36. [PMID: 12187980 DOI: 10.1016/s0021-9673(02)00135-8] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A simple device was developed for in-vial liquid-liquid extraction using a polymer membrane (nonporous polypropylene) to separate an aqueous sample from an organic extractant. The membrane consisted of tubing with an internal diameter of 6 mm and a wall thickness of 0.05 mm, which was heat-sealed at the lower end and filled with 500 microl hexane. This membrane bag was incorporated into a conventional 20 ml headspace vial suitable for a multi-purpose sampler (MPS 2, Gerstel, Mülheim, Germany) directly interfaced to a gas chromatograph with a mass-selective detector. The sampler enabled the extraction vial to be mixed at a defined temperature with subsequent large-volume injection of the organic extract taken from the membrane bag. The method was evaluated using several triazines, 2,4-dichloroaniline, alpha-hexachlorocyclohexane and phenanthrene as model compounds. Extraction parameters such as temperature, agitation speed, and extraction time were optimised. Recoveries of 60-90% were achieved after 30 min extraction. By increasing the injection volume to 100 microl, detection limits of 1-10 ng/l were determined.
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Affiliation(s)
- Barbara Hause
- Department of Analytical Chemistry, UFZ Centre for Environmental Research Leipzig-Halle, Leipzig, Germany.
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88
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Pedersen-Bjergaard S, Ho TS, Rasmussen KE. Fundamental studies on selectivity in 3-phase liquid-phase microextraction (LPME) of basic drugs. J Sep Sci 2002. [DOI: 10.1002/1615-9314(20020201)25:3<141::aid-jssc141>3.0.co;2-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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89
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Chapter 15 Liquid membrane techniques. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s0166-526x(02)80052-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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90
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91
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Grønhaug Halvorsen T, Pedersen-Bjergaard S, Rasmussen KE. Reduction of extraction times in liquid-phase microextraction. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 2001; 760:219-26. [PMID: 11530980 DOI: 10.1016/s0378-4347(01)00272-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Recently, we introduced a simple and inexpensive disposable device for liquid-phase microextraction (LPME) based on porous polypropylene hollow fibres. In the present paper, extraction times were significantly reduced by an increase in the surface of the hollow fibres. The model compounds methamphetamine and citalopram, were extracted from 2.5 ml of urine, plasma, and whole blood after dilution with water and alkalisation with 125 microl of 2 M NaOH though a porous polypropylene hollow fibre impregnated with hexyl ether and into an aqueous acceptor phase consisting of 0.1 M HCl. Two commercially available hollow fibres, which differed in surface area, wall thickness and internal diameter, were compared. An increase in the contact area of the hollow fibre with the sample solution by a factor of approximately two resulted in reduction in equilibrium times by approximately the same factor. Thus, the model compounds were extracted to equilibrium within 15 min from both urine and plasma, and within 30 min from whole blood. For the first time LPME was utilised to extract drugs from whole blood, and the extracts were comparable with plasma both with regard to sample clean-up and extraction recoveries. Extraction recoveries for methamphetamine and citalopram varied from 60 to 100% using the two fibres and the different matrices.
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92
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Kramer KE, Andrews AR. Screening method for 11-nor-delta9-tetrahydrocannabinol-9-carboxylic acid in urine using hollow fiber membrane solvent microextraction with in-tube derivatization. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 2001; 760:27-36. [PMID: 11522063 DOI: 10.1016/s0378-4347(01)00232-8] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
An efficient and inexpensive screening technique for the simultaneous clean-up, extraction, and derivatization of 11-nor-delta9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) from urine has been developed. Using the principles of solvent microextraction in the form of a 20-microl volume of solvent placed inside a permeable hydrophobic polypropylene hollow fiber membrane, the analyte of interest is preconcentrated inside this tubing as the bulk sample solution is stirred for a given extraction time. The pH of the sample is raised by adding buffer after which the charged moiety is extracted as an ion pair with tetramethylammonium hydrogen sulfate. Using a mixture of N,O-bis(trimethylsilyl)trifluoroacetamide and octane as the extraction solvent allows the GC-unstable carboxylic acid metabolite to be derivatized during the extraction without prior sample clean-up steps such as filtration of the urine. After an 8-min extraction, a 6-microl portion is drawn up with a syringe and directly injected into a gas chromatograph for separation and analysis. Samples as low as 10 ng ml(-1) were analyzed successfully and the limit of detection was estimated at 1.0 ng ml(-1) with relative standard deviations lower than 10% in the final protocol.
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Affiliation(s)
- K E Kramer
- Department of Chemistry and Biochemistry, Ohio University, Athens 45701-2979, USA
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Mullins FGP. Evaluation of a novel non-porous membrane extraction probe to determine sulphonylureas in plasma with analysis by LC-MS/MS. J Sep Sci 2001. [DOI: 10.1002/1615-9314(20010801)24:7<593::aid-jssc593>3.0.co;2-f] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Halvorsen TG, Pedersen-Bjergaard S, Reubsaet JLE, Rasmussen KE. Liquid-phase microextraction combined with flow-injection tandem mass spectrometry Rapid screening of amphetamines from biological matrices. J Sep Sci 2001. [DOI: 10.1002/1615-9314(20010801)24:7<615::aid-jssc615>3.0.co;2-z] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Hauser B, Popp P. Membrane-assisted solvent extraction of organochlorine compounds in combination with large-volume injection/gas chromatography-electron capture detection. J Sep Sci 2001. [DOI: 10.1002/1615-9314(20010801)24:7<551::aid-jssc551>3.0.co;2-2] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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