51
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Zhang Q, Yang F, Tang F, Zeng K, Wu K, Cai Q, Yao S. Ionic liquid-coated Fe3O4 magnetic nanoparticles as an adsorbent of mixed hemimicelles solid-phase extraction for preconcentration of polycyclic aromatic hydrocarbons in environmental samples. Analyst 2010; 135:2426-33. [DOI: 10.1039/c0an00245c] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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52
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Sheikhloie H, Saber-Tehrani M, Abrumand-Azar P, Waqif-Husain S. Analysis of tributyltin and triphenyltin in water by ionic liquid-headspace single-drop microextraction then HPLC with fluorimetric detection. ACTA CHROMATOGR 2009. [DOI: 10.1556/achrom.21.2009.4.5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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53
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Tsai WH, Huang TC, Chen HH, Wu YW, Huang JJ, Chuang HY. Determination of sulfonamides in swine muscle after salting-out assisted liquid extraction with acetonitrile coupled with back-extraction by a water/acetonitrile/dichloromethane ternary component system prior to high-performance liquid chromatography. J Chromatogr A 2009; 1217:250-5. [PMID: 19959176 DOI: 10.1016/j.chroma.2009.11.035] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 11/11/2009] [Accepted: 11/16/2009] [Indexed: 11/29/2022]
Abstract
A salting-out assisted liquid extraction coupled with back-extraction by a water/acetonitrile/dichloromethane ternary component system combined with high-performance liquid chromatography with diode-array detection (HPLC-DAD) was developed for the extraction and determination of sulfonamides in solid tissue samples. After the homogenization of the swine muscle with acetonitrile and salt-promoted partitioning, an aliquot of 1 mL of the acetonitrile extract containing a small amount of dichloromethane (250-400 microL) was alkalinized with diethylamine. The clear organic extract obtained by centrifugation was used as a donor phase and then a small amount of water (40-55 microL) could be used as an acceptor phase to back-extract the analytes in the water/acetonitrile/dichloromethane ternary component system. In the back-extraction procedure, after mixing and centrifuging, the sedimented phase would be water and could be withdrawn easily into a microsyringe and directly injected into the HPLC system. Under the optimal conditions, recoveries were determined for swine muscle fortified at 10 ng/g and quantification was achieved by matrix-matched calibration. The calibration curves of five sulfonamides showed linearity with the coefficient of estimation above 0.998. Relative recoveries for the analytes were all from 96.5 to 109.2% with relative standard deviation of 2.7-4.0%. Preconcentration factors ranged from 16.8 to 30.6 for 1 mL of the acetonitrile extract. Limits of detection ranged from 0.2 to 1.0 ng/g.
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Affiliation(s)
- Wen-Hsien Tsai
- Department of Food Science, National Pingtung University of Science and Technology, No. 1, Hseuh-Fu Road, Nei-Pu, Pingtung 91201, Taiwan
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54
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Jeannot MA, Przyjazny A, Kokosa JM. Single drop microextraction--development, applications and future trends. J Chromatogr A 2009; 1217:2326-36. [PMID: 19932482 DOI: 10.1016/j.chroma.2009.10.089] [Citation(s) in RCA: 176] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Revised: 10/28/2009] [Accepted: 10/29/2009] [Indexed: 11/29/2022]
Abstract
Single drop microextraction (SDME) has emerged over the last 10-15 years as one of the simplest and most easily implemented forms of micro-scale sample cleanup and preconcentration. In the most common arrangement, an ordinary chromatography syringe is used to suspend microliter quantities of extracting solvent either directly immersed in the sample, or in the headspace above the sample. The same syringe is then used to introduce the solvent and extracted analytes into the chromatography system for identification and/or quantitation. This review article summarizes the historical development and various modes of the technique, some theoretical and practical aspects, recent trends and selected applications.
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Affiliation(s)
- Michael A Jeannot
- Department of Chemistry, St. Cloud State University, 366 Wick Science Building, 720 4th Ave. S., St. Cloud, MN 56301-4498, USA.
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55
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Zhou Q, Zhang X, Xie G, Xiao J. Temperature-controlled ionic liquid-dispersive liquid-phase microextraction for preconcentration of chlorotoluron, diethofencarb and chlorbenzuron in water samples. J Sep Sci 2009; 32:3945-50. [DOI: 10.1002/jssc.200900444] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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56
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Fan YC, Chen ML, Shen-Tu C, Zhu Y. A ionic liquid for dispersive liquid-liquid microextraction of phenols. JOURNAL OF ANALYTICAL CHEMISTRY 2009. [DOI: 10.1134/s1061934809100074] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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57
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He L, Luo X, Xie H, Wang C, Jiang X, Lu K. Ionic liquid-based dispersive liquid-liquid microextraction followed high-performance liquid chromatography for the determination of organophosphorus pesticides in water sample. Anal Chim Acta 2009; 655:52-9. [PMID: 19925915 DOI: 10.1016/j.aca.2009.09.044] [Citation(s) in RCA: 182] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 09/29/2009] [Accepted: 09/29/2009] [Indexed: 11/24/2022]
Abstract
Using 1-octyl-3-methylimidazolium hexafluorophosphate ([C(8)MIM][PF(6)]) ionic liquid as extraction solvent, organophosphorus pesticides (OPPs) (parathion, phoxim, phorate and chlorpyifos) in water were determined by dispersive liquid-liquid microextraction (DLLME) combined with high-performance liquid chromatography (HPLC). The extraction procedure was induced by the formation of cloudy solution, which was composed of fine drops of [C(8)MIM][PF(6)] dispersed entirely into sample solution with the help of disperser solvent (methanol). Parameters including extraction solvent and its volume, disperser solvent and its volume, extraction time, centrifugal time, salt addition, extraction temperature and sample pH were investigated and optimized. Under the optimized conditions, up to 200-fold enrichment factor of analytes and acceptable extraction recovery (>70%) were obtained. The calibration curves were linear in the concentration range of 10.5-1045.0 microg L(-1) for parathion, 10.2-1020.0 microg L(-1) for phoxim, 54.5-1089.0 microg L(-1) for phorate and 27.2-1089.0 microg L(-1) for chlorpyifos, respectively. The limits of detection calculated at a signal-to-noise ratio of 3 were in the range of 0.1-5.0 microg L(-1). The relative standard deviations for seven replicate experiments at 200 microg L(-1) concentration level were less than 4.7%. The proposed method was applied to the analysis of four different sources water samples (tap, well, rain and Yellow River water) and the relative recoveries of spiked water samples are 99.9-115.4%, 101.8-113.7% and 87.3-117.6% at three different concentration levels of 75, 200 and 1000 microg L(-1), respectively.
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Affiliation(s)
- Lijun He
- School of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou 450001, China.
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58
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Laus G, Andre M, Bentivoglio G, Schottenberger H. Ionic liquids as superior solvents for headspace gas chromatography of residual solvents with very low vapor pressure, relevant for pharmaceutical final dosage forms. J Chromatogr A 2009; 1216:6020-3. [PMID: 19560778 DOI: 10.1016/j.chroma.2009.06.036] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Revised: 06/09/2009] [Accepted: 06/12/2009] [Indexed: 11/17/2022]
Abstract
1-n-Butyl-3-methylimidazolium dimethyl phosphate (BMIM DMP) was identified as the most suitable ionic liquid as solvent for the headspace gas chromatographic analysis of solvents with very low vapor pressure such as dimethylsulfoxide, N-methylpyrrolidone, sulfolane, tetralin, and ethylene glycol in a realistic matrix of commonly used excipients (carboxymethylcellulose, magnesium stearate, guar flour, and corn starch) in pharmaceutical products. Limits of quantification and limits of detection were in the low microgram per gram range. The detection of traces of sulfolane in a real sample of tablets containing the drug cefpodoxim proxetil demonstrated the applicability of the method.
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Affiliation(s)
- Gerhard Laus
- Faculty of Chemistry and Pharmacy, University of Innsbruck, Innrain 52a, 6020 Innsbruck, Austria
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59
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Gao Y, Zeng Y, Zheng L, Li L. Determination of Triazine Herbicides in Aqueous Samples Using Solidification of a Floating Drop for Liquid-Phase Microextraction with Liquid Chromatography. ANAL LETT 2009. [DOI: 10.1080/00032710902993837] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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60
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Aguilera-Herrador E, Lucena R, Cárdenas S, Valcárcel M. Ionic liquid-based single drop microextraction and room-temperature gas chromatography for on-site ion mobility spectrometric analysis. J Chromatogr A 2009; 1216:5580-7. [DOI: 10.1016/j.chroma.2009.05.071] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Revised: 05/25/2009] [Accepted: 05/25/2009] [Indexed: 10/20/2022]
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61
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Huang X, Qiu N, Yuan D, Lin Q. Sensitive determination of strongly polar aromatic amines in water samples by stir bar sorptive extraction based on poly(vinylimidazole-divinylbenzene) monolithic material and liquid chromatographic analysis. J Chromatogr A 2009; 1216:4354-60. [DOI: 10.1016/j.chroma.2009.03.043] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2009] [Revised: 03/14/2009] [Accepted: 03/17/2009] [Indexed: 11/28/2022]
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62
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Preparation of ionic liquid based solid-phase microextraction fiber and its application to forensic determination of methamphetamine and amphetamine in human urine. J Chromatogr A 2009; 1216:4824-30. [PMID: 19426983 DOI: 10.1016/j.chroma.2009.04.028] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Revised: 04/08/2009] [Accepted: 04/10/2009] [Indexed: 11/23/2022]
Abstract
A new solid-phase microextraction (SPME) procedure using an ionic liquid (IL) has been developed. Reusable IL-based SPME fiber was prepared for the first time by fixing IL through cross-linkage of IL impregnated silicone elastomer on the surface of a fused silica fiber. 1-Ethoxyethyl-3-methylimidazloium bis(trifluoromethane) sulfonylimide ([EeMim][NTf(2)]) ionic liquid was employed as a demonstration and the prepared fiber was applied to the forensic headspace determination of methamphetamine (MAP) and amphetamine (AP) in human urine samples. Important extraction parameters including the concentration of salt and base in sample matrix, extraction temperature and extraction time were investigated and optimized. Combined with gas chromatography/mass spectrometry (GC/MS) working in selected ion monitoring (SIM) mode, the new method showed good linearity in the range of 20-1500 microg L(-1), good repeatability (RSD<7.5% for MAP, and <11.5% for AP, n=6), and low detection limits (0.1 microg L(-1) for MAP and 0.5 microg L(-1) for AP). Feasibility of the method was evaluated by analyzing human urine samples. Although IL-based SPME is still at the beginning of its development stage, the results obtained by this work showed that it is a promising simple, fast and sensitive sample preparation method.
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63
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Farahani H, Ganjali MR, Dinarvand R, Norouzi P. Study on the performance of the headspace liquid-phase microextraction, gas chromatography-mass spectrometry in the determination of sorbic and benzoic acids in soft drinks and environmental water samples. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2009; 57:2633-2639. [PMID: 19334751 DOI: 10.1021/jf802981z] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A simple, efficient and virtually solventless headspace liquid-phase microextraction (HS-LPME) technique, combined with gas chromatography-mass spectrometry (GC-MS), was developed for the analysis of sorbic acid (SA) and benzoic acid (BA) in soft drinks and environmental water samples. A microdrop of organic solvent was suspended from the tip of a microsyringe needle over the headspace of the stirred sample solution, containing the analytes for a desired time. The microdrop was then retracted into the microsyringe and directly injected into the GC-MS, without any further pretreatment. Initially, microextraction efficiency factors were optimized, and the optimum experimental conditions found were as follows: 2.5 microL toluene microdrop exposed for 20 min over the headspace of a 6.5 mL aqueous sample (45 degrees C), containing 3 M of NaCl with pH of 1.5 and stirred at 1000 rpm. Under the optimized extraction conditions, preconcentration factors of 154 and 198, limits of detection of 0.3 and 0.1 microg L(-1) (S/N=3) with dynamic linear ranges of 1-500 and 0.5-500 microg L(-1), were obtained for SA and BA respectively. A good repeatability (RSD<10.3%, n=8) and satisfactory linearity (r(2) >or= 0.99) of results were achieved. The accuracy of the method was tested by the relative recovery experiments on spiked samples, with results ranging from 90 to 113%. The method proved to be rapid and cost-effective and is a green procedure for screening purposes.
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Affiliation(s)
- Hadi Farahani
- Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, P.O. Box 14155-6455, Tehran, Iran
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64
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Yao C, Anderson JL. Retention characteristics of organic compounds on molten salt and ionic liquid-based gas chromatography stationary phases. J Chromatogr A 2009; 1216:1658-712. [DOI: 10.1016/j.chroma.2008.12.001] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2008] [Revised: 11/28/2008] [Accepted: 12/02/2008] [Indexed: 11/29/2022]
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65
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Basheer C, Alnedhary AA, Madhava Rao B, Balasubramanian R, Lee HK. Ionic liquid supported three-phase liquid–liquid–liquid microextraction as a sample preparation technique for aliphatic and aromatic hydrocarbons prior to gas chromatography-mass spectrometry. J Chromatogr A 2008; 1210:19-24. [DOI: 10.1016/j.chroma.2008.09.040] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2007] [Revised: 09/08/2008] [Accepted: 09/09/2008] [Indexed: 11/25/2022]
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66
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Liu XY, Ji YS, Zhang HX, Liu MC. Highly sensitive analysis of substituted aniline compounds in water samples by using oxidized multiwalled carbon nanotubes as an in-tube solid-phase microextraction medium. J Chromatogr A 2008; 1212:10-5. [DOI: 10.1016/j.chroma.2008.10.034] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Revised: 09/11/2008] [Accepted: 10/10/2008] [Indexed: 10/21/2022]
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67
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Ionic liquids in sample preparation. Anal Bioanal Chem 2008; 393:871-83. [DOI: 10.1007/s00216-008-2445-6] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Revised: 09/25/2008] [Accepted: 09/30/2008] [Indexed: 10/21/2022]
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68
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Critical review on recent developments in solventless techniques for extraction of analytes. Anal Bioanal Chem 2008; 393:809-33. [DOI: 10.1007/s00216-008-2437-6] [Citation(s) in RCA: 189] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2008] [Accepted: 09/24/2008] [Indexed: 10/21/2022]
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69
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Aguilera-Herrador E, Lucena R, Cárdenas S, Valcárcel M. Determination of trihalomethanes in waters by ionic liquid-based single drop microextraction/gas chromatographic/mass spectrometry. J Chromatogr A 2008; 1209:76-82. [DOI: 10.1016/j.chroma.2008.09.030] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Revised: 09/03/2008] [Accepted: 09/08/2008] [Indexed: 10/21/2022]
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70
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Zhao FQ, Li J, Zeng BZ. Coupling of ionic liquid-based headspace single-drop microextraction with GC for sensitive detection of phenols. J Sep Sci 2008; 31:3045-9. [DOI: 10.1002/jssc.200800308] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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71
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Yan X, Yang C, Ren C, Li D. Importance of extracting solvent vapor pressure in headspace liquid-phase microextraction. J Chromatogr A 2008; 1205:182-5. [PMID: 18723174 DOI: 10.1016/j.chroma.2008.08.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Revised: 08/07/2008] [Accepted: 08/08/2008] [Indexed: 10/21/2022]
Abstract
Of the many parameters that affect the enrichment factors in headspace liquid-phase microextraction, in this study, we systematically investigated the influence of the vapor pressure of the extracting solvent. Seven extracting solvents with different vapor pressures were selected and tested. It was found that the vapor pressure of the extracting solvent dramatically affects the enrichment factor and the factor was increasing by decreasing the extracting solvent vapor pressure under given experimental conditions. The result was validated for volatile organic compounds such as polynuclear aromatic hydrocarbons, organochlorine pesticides and polychlorinated biphenyls.
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Affiliation(s)
- Xue Yan
- Department of Chemistry, College of Science, Yanbian University, Park Road 977, Yanji City 133002, Jilin Province, China
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72
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Ionic liquid-based single-drop microextraction/gas chromatographic/mass spectrometric determination of benzene, toluene, ethylbenzene and xylene isomers in waters. J Chromatogr A 2008; 1201:106-11. [DOI: 10.1016/j.chroma.2008.06.010] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2008] [Revised: 06/03/2008] [Accepted: 06/11/2008] [Indexed: 10/21/2022]
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73
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Fan YC, Hu ZL, Chen ML, Tu CS, Zhu Y. Ionic liquid based dispersive liquid–liquid microextraction of aromatic amines in water samples. CHINESE CHEM LETT 2008. [DOI: 10.1016/j.cclet.2008.05.024] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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74
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Single-drop coacervative microextraction of organic compounds prior to liquid chromatography. J Chromatogr A 2008; 1195:25-33. [DOI: 10.1016/j.chroma.2008.05.002] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Revised: 03/19/2008] [Accepted: 05/07/2008] [Indexed: 11/17/2022]
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75
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Zhou Q, Bai H, Xie G, Xiao J. Trace determination of organophosphorus pesticides in environmental samples by temperature-controlled ionic liquid dispersive liquid-phase microextraction. J Chromatogr A 2008; 1188:148-53. [PMID: 18346747 DOI: 10.1016/j.chroma.2008.02.094] [Citation(s) in RCA: 222] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2007] [Revised: 02/18/2008] [Accepted: 02/22/2008] [Indexed: 11/29/2022]
Abstract
This paper described a new approach for the determination of organophosphorus pesticides by temperature-controlled ionic liquid dispersive liquid-phase microextraction prior to high-performance liquid chromatography with ultraviolet detection. Methylparathion and phoxim, two of the typical organophosphorus pesticides, were used as the model analytes for the investigation of the development and application of the new microextraction method. 1-Hexyl-3-methylimidazolium hexafluorophosphate [C6MIM][PF6] was used as the extraction solvent and the factors affecting the extraction efficiency such as the volume of [C6MIM][PF6], pH of working solutions, extraction time, centrifuging time, dissoluble temperature and salt effect were optimized. Under the optimal extraction conditions, methylparathion and phoxim exhibited good linear relationship in the concentration range of 1-100 ng mL(-1). The detection limits were 0.17 ng mL(-1) and 0.29 ng mL(-1), respectively. Precisions of proposed method (RSDs, n=6) were 2.5% and 2.7%, respectively. This proposed method was successfully applied in the analysis of four real environmental water samples and good spiked recoveries over the range of 88.2-103.6% were obtained. These results indicated that temperature-controlled ionic liquid dispersive liquid-phase microextraction had excellent application prospect in environmental field.
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Affiliation(s)
- Qingxiang Zhou
- School of Chemistry and Environmental Sciences, Henan Normal University, Henan Key Laboratory for Environmental Pollution Control, Xinxiang 453007, China.
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76
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Hsieh YN, Horng RS, Ho WY, Huang PC, Hsu CY, Whang TJ, Kuei CH. Characterizations for Vinylimidazolium Based Ionic Liquid Polymer Stationary Phases for Capillary Gas Chromatography. Chromatographia 2008. [DOI: 10.1365/s10337-008-0531-8] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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77
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Abstract
Ionic liquids are liquids composed completely of ions. In the past two decades, ionic liquids have been widely used as "green solvents" replacing traditional organic solvents for organic synthesis and catalysis. In addition, ionic liquids are playing an increasingly important role in separation science. In this Account, the application of ionic liquids in all areas of separation science including extractions, gas chromatography, and supported liquid membrane processes are highlighted.
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Affiliation(s)
- Xinxin Han
- Department of Chemistry & Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019, USA
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78
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Xu H, Liao Y, Yao J. Development of a novel ultrasound-assisted headspace liquid-phase microextraction and its application to the analysis of chlorophenols in real aqueous samples. J Chromatogr A 2007; 1167:1-8. [PMID: 17765249 DOI: 10.1016/j.chroma.2007.08.022] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Revised: 08/02/2007] [Accepted: 08/03/2007] [Indexed: 11/30/2022]
Abstract
A new sample pretreatment technique, ultrasound-assisted headspace liquid-phase microextraction was developed as mentioned in this paper. In the technique, the volatile analytes were headspace extracted into a small drop of solvent, which suspended on the bottom of a cone-shaped PCR tube instead of the needle tip of a microsyringe. More solvent could be suspended in the PCR tube than microsyringe due to the larger interfacial tension, thus the analysis sensitivity was significantly improved with the increase of the extractant volume. Moreover, ultrasound-assisted extraction and independent controlling temperature of the extractant and the sample were performed to enhance the extraction efficiency. Following the extraction, the solvent-loaded sample was analyzed by high-performance liquid chromatography. Chlorophenols (2-chlorophenol, 2,4-dichlorophenol and 2,6-dichlorophenol) were chosen as model analytes to investigate the feasibility of the method. The experimental conditions related to the extraction efficiency were systematically studied. Under the optimum experimental conditions, the detection limit (S/N=3), intra- and inter-day RSD were 6 ng mL(-1), 4.6%, 3.9% for 2-chlorophenol, 12 ng mL(-1), 2.4%, 8.8% for 2,4-dichlorophenol and 23 ng mL(-1), 3.3%, 5.3% for 2,6-dichlorophenol, respectively. The proposed method was successfully applied to determine chlorophenols in real aqueous samples. Good recoveries ranging from 84.6% to 100.7% were obtained. In addition, the extraction efficiency of our method and the conventional headspace liquid-phase microextraction were compared; the extraction efficiency of the former was about 21 times higher than that of the latter. The results demonstrated that the proposed method is a promising sample pretreatment approach, its advantages over the conventional headspace liquid-phase microextraction include simple setup, ease of operation, rapidness, sensitivity, precision and no cross-contamination. The method is very suitable for the analysis of trace volatile and semivolatile pollutants in real aqueous sample.
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Affiliation(s)
- Hui Xu
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, China.
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79
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Ionic liquid for improved single-drop microextraction of aromatic amines in water samples. Mikrochim Acta 2007. [DOI: 10.1007/s00604-007-0857-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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80
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Lambropoulou DA, Konstantinou IK, Albanis TA. Recent developments in headspace microextraction techniques for the analysis of environmental contaminants in different matrices. J Chromatogr A 2007; 1152:70-96. [PMID: 17379234 DOI: 10.1016/j.chroma.2007.02.094] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2006] [Revised: 02/23/2007] [Accepted: 02/26/2007] [Indexed: 11/24/2022]
Abstract
Headspace microextraction procedures such as solid-phase microextraction (SPME) and single drop microextraction (SDME) or liquid-phase microextraction (LPME) are increasingly used for the extraction of environmental organic pollutants from a variety of aqueous, viscous, semisolid and solid environmental and biological matrices. In this article, recent analytical applications of these methodologies when used as an isolation and trace enrichment step prior to the analysis of organic pollutants (pesticides, polycyclic aromatic hydrocarbons, polychlorinated compounds, organotin compounds, phenolic derivatives, aromatic amines, phthalates, etc.) by gas and liquid chromatography are reviewed. The applicability and inherent limitations of headspace microextraction are also discussed. The future direction of research in this field and general trends toward commercial applications are considered.
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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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81
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Xu L, Basheer C, Lee HK. Developments in single-drop microextraction. J Chromatogr A 2007; 1152:184-92. [PMID: 17097670 DOI: 10.1016/j.chroma.2006.10.073] [Citation(s) in RCA: 263] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2006] [Revised: 10/27/2006] [Accepted: 10/30/2006] [Indexed: 11/22/2022]
Abstract
Single-drop microextraction (SDME) has become a very popular liquid-phase microextraction technique because it is inexpensive, easy to operate and nearly solvent-free. Essentially, SDME combines extraction (and conceivably, cleanup) and concentration in a minimum number of steps, and thereafter, direct extract introduction into an analytical system. In this review, in order to encourage further development of SDME, we focus on its recent developments in its various guises. Its applications when used in combination with different analytical techniques, such as gas chromatography, high-performance liquid chromatography, inductively-coupled plasma mass spectrometry, capillary electrophoresis, mass spectrometry and electrothermal atomic absorption spectrometry, are summarized. SDME does have some limitations, and these are also discussed as well. Finally, an outlook on the future of the technique is given.
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Affiliation(s)
- Li Xu
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
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82
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Headspace liquid-phase microextraction of methamphetamine and amphetamine in urine by an aqueous drop. Anal Chim Acta 2007; 589:225-30. [PMID: 17418185 DOI: 10.1016/j.aca.2007.02.064] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2006] [Revised: 02/23/2007] [Accepted: 02/23/2007] [Indexed: 11/25/2022]
Abstract
This study developed a headspace liquid-phase microextraction (LPME) method by using a single aqueous drop in combination with high performance liquid chromatography (HPLC)-UV detection for the determination of methamphetamine (MAP) and amphetamine (AP) in urine samples. The analytes, volatile and basic, were released from sample matrix into the headspace first, and then protonated and dissolved in an aqueous H(3)PO(4) drop hanging in the headspace by a HPLC syringe. After extraction, this drop was directly injected into HPLC. Parameters affecting extraction efficiency were investigated and optimized. This method showed good linearity in the investigated concentration range of 1.0-1500 microg L(-1), repeatability of the extraction (R.S.D.<5%, n=6), and low detection limits (0.3 microg L(-1) for both analytes). Enrichment factors of about 400-fold and 220-fold were achieved for MAP and AP, respectively, at optimum conditions. The feasibility of the method was demonstrated by analyzing human urine samples.
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83
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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: 170] [Impact Index Per Article: 10.0] [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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84
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Polyakova Y, Jin Y, Zheng J, Ho Row K. Effect of Concentration of Ionic Liquid 1‐Butyl‐3‐Methylimidazolium, Tetrafuoroborate, for Retention and Separation of Some Amino and Nucleic Acids. J LIQ CHROMATOGR R T 2007. [DOI: 10.1080/10826070600716769] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Yulia Polyakova
- a Center for Advanced Bioseparation Technology and Department of Chemical Engineering , Inha University , Nam‐Ku, Incheon, Korea
| | - Yinzhe Jin
- a Center for Advanced Bioseparation Technology and Department of Chemical Engineering , Inha University , Nam‐Ku, Incheon, Korea
| | - Jinzhu Zheng
- a Center for Advanced Bioseparation Technology and Department of Chemical Engineering , Inha University , Nam‐Ku, Incheon, Korea
| | - Kyung Ho Row
- a Center for Advanced Bioseparation Technology and Department of Chemical Engineering , Inha University , Nam‐Ku, Incheon, Korea
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85
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Vidal L, Psillakis E, Domini CE, Grané N, Marken F, Canals A. An ionic liquid as a solvent for headspace single drop microextraction of chlorobenzenes from water samples. Anal Chim Acta 2007; 584:189-95. [PMID: 17386603 DOI: 10.1016/j.aca.2006.10.053] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Revised: 10/25/2006] [Accepted: 10/31/2006] [Indexed: 10/23/2022]
Abstract
A headspace single-drop microextraction (HS-SDME) procedure using room temperature ionic liquid and coupled to high-performance liquid chromatography capable of quantifying trace amounts of chlorobenzenes in environmental water samples is proposed. A Plackett-Burman design for screening was carried out in order to determine the significant experimental conditions affecting the HS-SDME process (namely drop volume, aqueous sample volume, stirring speed, ionic strength, extraction time and temperature), and then a central composite design was used to optimize the significant conditions. The optimum experimental conditions found from this statistical evaluation were: a 5 microL microdrop of 1-butyl-3-methylimidazolium hexafluorophosphate, exposed for 37 min to the headspace of a 10 mL aqueous sample placed in a 15 mL vial, stirred at 1580 rpm at room temperature and containing 30% (w/v) NaCl. The calculated calibration curves gave a high level of linearity for all target analytes with correlation coefficients ranging between 0.9981 and 0.9997. The repeatability of the proposed method, expressed as relative standard deviation, varied between 1.6 and 5.1% (n=5). The limits of detection ranged between 0.102 and 0.203 microg L(-1). Matrix effects upon extraction were evaluated by analysing spiked tap and river water as well as effluent water samples originating from a municipal wastewater treatment plant.
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Affiliation(s)
- Lorena Vidal
- Departamento de Química Analítica, Nutrición y Bromatología, Universidad de Alicante, P.O. Box 99, E-03080 Alicante, Spain
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86
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Wang GQ, Zhang RJ, Sun YA, Xie K, Ma CY. Characterization and Semiquantitative Analysis of Volatile Compounds in Orange Juice by Use of Headspace-Solvent Microextraction and Gas Chromatography. Chromatographia 2007. [DOI: 10.1365/s10337-006-0168-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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87
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Ye C, Zhou Q, Wang X, Xiao J. Determination of phenols in environmental water samples by ionic liquid-based headspace liquid-phase microextraction coupled with high-performance liquid chromatography. J Sep Sci 2007; 30:42-7. [PMID: 17313140 DOI: 10.1002/jssc.200600256] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Headspace liquid-phase microextraction (HS-LPME) has been applied to efficient enrichment of phenols such as 2-nitrophenol, 4-chlorophenol, 2,4-dichlorophenol, and 2-naphthol from water samples based on 1-butyl-3-methylimidazolium hexafluorophosphate ([C4MIM][PF6]) as an extractant. Some parameters that may influence HS-LPME were investigated. The linear range was in the range of 0.5-100 microg/L, and the enrichment factors and repeatability (RSD, n = 6) of the proposed method were in the range of 17.2-160.7 and 5.4-8.9%, respectively. The detection limit for each analyte ranged from 0.3 to 0.5 microg/L. Complex matrices of environmental water samples had a small effect on the enrichment, and this problem could be resolved by the addition of sodium ethylene diamine tetraacetate (EDTA) into the samples. The spiked recoveries were in the range of 89.4-114.2%. All these facts demonstrated that the proposed method, with merits of low cost, simplicity, and easy operation, would be a competitive alternative procedure for the determination of such compounds at trace level.
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Affiliation(s)
- Cunling Ye
- School of Chemistry and Environmental Sciences, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, Henan, P. R. China
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88
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Peng JF, Liu JF, Hu XL, Jiang GB. Direct determination of chlorophenols in environmental water samples by hollow fiber supported ionic liquid membrane extraction coupled with high-performance liquid chromatography. J Chromatogr A 2007; 1139:165-70. [PMID: 17113589 DOI: 10.1016/j.chroma.2006.11.006] [Citation(s) in RCA: 234] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2006] [Revised: 11/02/2006] [Accepted: 11/03/2006] [Indexed: 11/19/2022]
Abstract
The 1-octyl-3-methylimidazolium hexafluorophosphate ([C8MIM][PF6]) ionic liquid was immobilized in the pores of a polypropylene hollow fiber for hollow fiber-protected liquid-phase microextraction. Analytes including 4-chlorophenol (4-CP), 3-chorophenol (3-CP), 2,4-dichlorophenol (2,4-DCP) and 2,4,6-trichlorophenol (2,4,6-TCP) were extracted into this ionic liquid membrane, and back extracted into 10microL sodium hydroxide acceptor solution in the lumen of the hollow fiber. Then, the acceptor solution was withdrawn into the high-performance liquid chromatography (HPLC) microsyringe connected to the hollow fiber, and directly injected into the HPLC system for analysis. Some parameters that might affect the extraction efficiency were optimized, and low detection limits (0.5microgL(-1) for 4-CP, 3-CP, DCP and 1.0microgL(-1) for TCP) were obtained. Good repeatability was achieved because of the stability of the hollow fiber-supported ionic liquid membrane. The proposed procedure was applied for direct determination of the four chlorophenols in some real water samples including groundwater, river water, wastewater and tap water. All of the four chlorophenols in these water samples were under the limits of determination, and the recoveries were in the range of 70.0-95.7% at 5microgL(-1) spiked level.
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Affiliation(s)
- Jin-Feng Peng
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China
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89
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Ye C, Zhou Q, Wang X. Improved single-drop microextraction for high sensitive analysis. J Chromatogr A 2007; 1139:7-13. [PMID: 17113592 DOI: 10.1016/j.chroma.2006.10.089] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2006] [Revised: 10/25/2006] [Accepted: 10/30/2006] [Indexed: 11/18/2022]
Abstract
This paper described a simple approach to prepare a small bell-mouthed extraction device for single-drop microextraction (SDME). Analytical sensitivity was improved by increasing the suspended acceptor volume. Because of the increased contact area and the rough inner surface of the extraction device, the stability of drop was markedly increased. The merits of the proposed method were demonstrated by using 1-octanol as extractant and with cyanazine, simazine and atrazine as model compounds. The related parameters and the effect of humic acid were systematically investigated. Under the optimized extraction conditions, the linear range, detection limit (S/N=3) and precision (RSD, n=6) were 0.2-50, 0.06microgL-1, 5.7% for cyanazine, 0.1-25, 0.03microgL-1, 6.7% for simazine, and 0.15-37.5, 0.04microgL-1, 5.0% for atrazine, respectively. The established method was applied to determine the target compounds in four real water samples, and the satisfactory spiked recoveries at two concentration levels were obtained. Moreover, the comparison of the proposed SDME with the traditional SDME was performed. These results indicated that the proposed improvement made SDME be a competitive analytical tool and an alternative of the traditional methods for the analysis of organic pollutants at trace level.
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Affiliation(s)
- Cunling Ye
- School of Chemistry and Environmental Sciences, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, Henan 453007, China
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90
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Retention factors and resolutions of amino benzoic acid isomers with some lonic liquids. BIOTECHNOL BIOPROC E 2006. [DOI: 10.1007/bf02932070] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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91
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Zhou Q, Ding Y, Xiao J. Simultaneous Determination of Cyanazine, Chlorotoluron and Chlorbenzuron in Environmental Water Samples with SPE Multiwalled Carbon Nanotubes and LC. Chromatographia 2006. [DOI: 10.1365/s10337-006-0111-8] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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92
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He Y, Kang YJ. Single drop liquid-liquid-liquid microextraction of methamphetamine and amphetamine in urine. J Chromatogr A 2006; 1133:35-40. [PMID: 16950324 DOI: 10.1016/j.chroma.2006.08.047] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2006] [Revised: 08/07/2006] [Accepted: 08/10/2006] [Indexed: 11/21/2022]
Abstract
Single drop liquid-liquid-liquid microextraction (LLLME) combined with high performance liquid chromatography (HPLC)-UV detection was investigated for the determination of a popular drug of abuse, methamphetamine (MAP), and its major metabolite, amphetamine (AP), in urine samples. The target compounds were extracted from NaOH modified sample solution to a thin layer of organic solvent membrane, and back-extracted to an acidic acceptor drop suspended on the tip of a 50-microL HPLC syringe in the aforementioned organic layer. This syringe was also used for direct injection after extraction. Factors affecting extraction efficiency were studied. At optimal conditions, the overall enrichment factor (EF) was 500-fold for AP and 730-fold for MAP, respectively. The method exhibited a wide linear range (1.0-1500 microg/L), low detection limit (0.5 microg/L), and good repeatability (RSD<5.0%) for both analytes. The feasibility of the method was demonstrated by the analysis of human urine samples.
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Affiliation(s)
- Yi He
- Department of Sciences, John Jay College of Criminal Justice, The City University of New York, 445 W 59th Street, New York, NY 10019, USA.
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93
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Ye CL, Zhou QX, Wang XM. Headspace liquid-phase microextraction using ionic liquid as extractant for the preconcentration of dichlorodiphenyltrichloroethane and its metabolites at trace levels in water samples. Anal Chim Acta 2006; 572:165-71. [PMID: 17723474 DOI: 10.1016/j.aca.2006.05.052] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2006] [Revised: 05/13/2006] [Accepted: 05/18/2006] [Indexed: 10/24/2022]
Abstract
A novel technique, high temperature headspace liquid-phase microextraction (HS-LPME) with room temperature ionic liquid (RTIL), 1-butyl-3-methylimidazolium hexafluorophosphate ([C4MIM][PF6]) as extractant, was developed for the analysis of dichlorodiphenyltrichloroethane (p,p'-DDT and o,p'-DDT) and its metabolites including 4,4'-dichlorodiphenyldichloroethylene (p,p'-DDE) and 4,4'-dichlorodiphenyldichloroethane (p,p'-DDD) in water samples by high performance liquid chromatography with ultraviolet detection. The parameters such as salt content, sample pH and temperature, stirring rate, extraction time, microdrop volume, and sample volume, were found to have significant influence on the HS-LPME. The conditions optimized for extraction of target compounds were as follows: 35% NaCl (w/v), neutral pH condition, 70 degrees C, 800 rpm, 30 min, 10 microL [C4MIM][PF6], and 25 mL sample solutions. Under the optimized conditions, the linear range, detection limit (S/N=3), and precision (R.S.D., n=6) were 0.3-30 microg L(-1), 0.07 microg L(-1), and 8.0% for p,p'-DDD, 0.3-30 microg L(-1), 0.08 microg L(-1), and 7.1% for p,p'-DDT, 0.3-30 microg L(-1), 0.08 microg L(-1), and 7.2% for o,p'-DDT, and 0.2-30 microg L(-1), 0.05 microg L(-1), and 6.8% for p,p'-DDE, respectively. Water samples including tap water, well water, snow water, reservoir water, and wastewater were analyzed by the proposed procedure and the recoveries at 5 microg L(-1) spiked level were in the range of 86.8-102.6%.
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Affiliation(s)
- Cun-Ling Ye
- School of Chemistry and Environmental Sciences, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, Henan 453007, PR China
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94
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Quintana JB, Rodríguez I. Strategies for the microextraction of polar organic contaminants in water samples. Anal Bioanal Chem 2006; 384:1447-61. [PMID: 16496135 DOI: 10.1007/s00216-005-0242-z] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2005] [Revised: 11/14/2005] [Accepted: 11/18/2005] [Indexed: 10/25/2022]
Abstract
In this paper the most recent developments in the microextraction of polar analytes from aqueous environmental samples are critically reviewed. The particularities of different microextraction approaches, mainly solid-phase microextraction (SPME), stir-bar-sorptive extraction (SBSE), and liquid-phase microextraction (LPME), and their suitability for use in combination with chromatographic or electrically driven separation techniques for determination of polar species are discussed. The compatibility of microextraction techniques, especially SPME, with different derivatisation strategies enabling GC determination of polar analytes and improving their extractability is revised. In addition to the use of derivatisation reactions, the possibility of enhancing the yield of solid-phase microextraction methods for polar analytes by using new coatings and/or larger amounts of sorbent is also considered. Finally, attention is also focussed on describing the versatility of LPME in its different possible formats and its ability to improve selectivity in the extraction of polar analytes with acid-base properties by using separation membranes and buffer solutions, instead of organic solvents, as the acceptor solution.
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Affiliation(s)
- José Benito Quintana
- Department of Water Quality Control, Technical University of Berlin, Sekr KF 4, Strasse des 17 Juni 135, 10623, Berlin, Germany.
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95
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Kánya Z, Forgács E, Cserháti T, Illés Z. Reducing Dimensionality in Principal Component Analysis – A Method Comparison. Chromatographia 2006. [DOI: 10.1365/s10337-005-0687-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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96
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Hsieh YN, Huang PC, Sun IW, Whang TJ, Hsu CY, Huang HH, Kuei CH. Nafion membrane-supported ionic liquid–solid phase microextraction for analyzing ultra trace PAHs in water samples. Anal Chim Acta 2006. [DOI: 10.1016/j.aca.2005.10.019] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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97
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Laamanen PL, Busi S, Lahtinen M, Matilainen R. A new ionic liquid dimethyldinonylammonium bromide as a flow modifier for the simultaneous determination of eight carboxylates by capillary electrophoresis. J Chromatogr A 2005; 1095:164-71. [PMID: 16275297 DOI: 10.1016/j.chroma.2005.07.111] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2005] [Revised: 07/26/2005] [Accepted: 07/27/2005] [Indexed: 11/22/2022]
Abstract
Two new methods of capillary zone electrophoresis based on aqueous phosphate running buffers with UV spectrophotometric detection were developed and optimized for the determination of eight carboxylates as copper complexes. Metalcomplexes are negatively charged, so measurements were made as anion analyses with flow reversal in the capillary. Two flow modifiers were used: a common tetradecyltrimethylammonium bromide (TTAB) and a new ionic liquid dimethyldinonylammonium bromide (DMDNAB). The methods were compared to each other. Better separation was achieved with DMDNAB as the flow modifier. Method development was done using a fused silica capillary (61 cm x 50 microm i.d.). Optimization was done using 95 mmol L(-1) phosphate buffer with TTAB or DMDNAB in the concentration 0.5 mmol L(-1) at pH 7.1. A -20 kV voltage and direct UV detection at 254 nm was used in measurements. In both CE methods all the peaks in the electropherograms were properly separated, the calibration plots gave good correlation coefficients and all eight carboxylates were detected in less than 7.5 min. The two methods were tested with natural water samples and a paper mill sample, and proved to be feasible.
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