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Phase equilibrium and partition coefficient of selected pesticides and nitrophenols in double and triple-phase liquid-phase microextraction

A two-phase and three-phase hollow fiber-protected liquid-phase microextraction method (HF-LPME) has been developed and used for the determination of partition coefficient and analysis of selected pesticides and nitrophenols in water samples. For two-phase HF-LPME, the analysis was performed by gas...

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Main Author: Zainal Abidin, Nurul Auni
Format: Thesis
Language:English
Published: 2009
Subjects:
QD Chemistry
Online Access:http://eprints.utm.my/id/eprint/11123/1/NurulAuniZainalMFS2009.pdf
http://eprints.utm.my/id/eprint/11123/
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spelling my.utm.111232018-06-04T09:51:20Z http://eprints.utm.my/id/eprint/11123/ Phase equilibrium and partition coefficient of selected pesticides and nitrophenols in double and triple-phase liquid-phase microextraction Zainal Abidin, Nurul Auni QD Chemistry A two-phase and three-phase hollow fiber-protected liquid-phase microextraction method (HF-LPME) has been developed and used for the determination of partition coefficient and analysis of selected pesticides and nitrophenols in water samples. For two-phase HF-LPME, the analysis was performed by gas chromatography-electron capture detector (GC-ECD). Extraction conditions of the selected pesticides were optimized. The following conditions have been selected as the optimum extraction conditions: toluene as organic solvent, 4 mL water samples, 20 min extraction time, 850 rpm stirring rate, 1.8 cm HF length, 1.5% (w/v) NaCl content, and pH 3. The analytes were extracted from 4 mL donor phase through 4 µL of an organic solvent immobilized in the pores of a porous polypropylene hollow fiber and then into the acceptor phase present inside the hollow fiber. Correlation coefficients (r2) of 0.996-0.997 and limits of detection (LOD) of 0.0026-0.0028 µg/L were achieved under the optimized conditions. The proposed method provided good average enrichment factors of up to 350-fold and successfully determined the partition coefficient for the selected analytes that were found to be directly correlated to the enrichment factor. In the three-phase HF-LPME technique coupled with HPLC, nitrophenols were extracted from 2.5 mL aqueous solution with the adjustment of pH in the range of 3.0-5.0 (donor solution) into an organic phase (1-hexanol) immobilized in the pores of the hollow fiber and finally back-extracted into 5.0 µL of the acceptor microdrop (pH 12.0) located at the end of the microsyringe needle. After a prescribed back-extraction time, the acceptor microdrop was withdrawn into the microsyringe and directly injected into the HPLC system under the optimum conditions (donor solution: 1.0 M H3PO4, pH 3.0-5.0; organic solvent: 1-hexanol; acceptor solution: 5 µL of 0.1 M NaOH, pH 8.0-12.0; agitation rate: 1050 rpm; extraction time: 15 min). The calibration curve for these analytes was linear in the range of 0.6-200 µg/L with r2 > 0.9994 was achieved under the optimized conditions. The enrichment factors of up to 500-fold were obtained. In this work, determination of analytes partition coefficients in three-phase HF-LPME has been successfully achieved. This study found that the partition coefficient (Ka/d) values were high for 2-nitrophenol and 3-nitrophenol and the individual partition coefficients (Korg/d and Ka/org) promoted efficient simultaneous extraction from the donor through the organic phase and further into the acceptor phase. Both methods were successfully applied for the analysis of water samples. 2009-10 Thesis NonPeerReviewed application/pdf en http://eprints.utm.my/id/eprint/11123/1/NurulAuniZainalMFS2009.pdf Zainal Abidin, Nurul Auni (2009) Phase equilibrium and partition coefficient of selected pesticides and nitrophenols in double and triple-phase liquid-phase microextraction. Masters thesis, Universiti Teknologi Malaysia, Faculty of Science.
institution Universiti Teknologi Malaysia
building UTM Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Teknologi Malaysia
content_source UTM Institutional Repository
url_provider http://eprints.utm.my/
language English
topic QD Chemistry
spellingShingle QD Chemistry
Zainal Abidin, Nurul Auni
Phase equilibrium and partition coefficient of selected pesticides and nitrophenols in double and triple-phase liquid-phase microextraction
description A two-phase and three-phase hollow fiber-protected liquid-phase microextraction method (HF-LPME) has been developed and used for the determination of partition coefficient and analysis of selected pesticides and nitrophenols in water samples. For two-phase HF-LPME, the analysis was performed by gas chromatography-electron capture detector (GC-ECD). Extraction conditions of the selected pesticides were optimized. The following conditions have been selected as the optimum extraction conditions: toluene as organic solvent, 4 mL water samples, 20 min extraction time, 850 rpm stirring rate, 1.8 cm HF length, 1.5% (w/v) NaCl content, and pH 3. The analytes were extracted from 4 mL donor phase through 4 µL of an organic solvent immobilized in the pores of a porous polypropylene hollow fiber and then into the acceptor phase present inside the hollow fiber. Correlation coefficients (r2) of 0.996-0.997 and limits of detection (LOD) of 0.0026-0.0028 µg/L were achieved under the optimized conditions. The proposed method provided good average enrichment factors of up to 350-fold and successfully determined the partition coefficient for the selected analytes that were found to be directly correlated to the enrichment factor. In the three-phase HF-LPME technique coupled with HPLC, nitrophenols were extracted from 2.5 mL aqueous solution with the adjustment of pH in the range of 3.0-5.0 (donor solution) into an organic phase (1-hexanol) immobilized in the pores of the hollow fiber and finally back-extracted into 5.0 µL of the acceptor microdrop (pH 12.0) located at the end of the microsyringe needle. After a prescribed back-extraction time, the acceptor microdrop was withdrawn into the microsyringe and directly injected into the HPLC system under the optimum conditions (donor solution: 1.0 M H3PO4, pH 3.0-5.0; organic solvent: 1-hexanol; acceptor solution: 5 µL of 0.1 M NaOH, pH 8.0-12.0; agitation rate: 1050 rpm; extraction time: 15 min). The calibration curve for these analytes was linear in the range of 0.6-200 µg/L with r2 > 0.9994 was achieved under the optimized conditions. The enrichment factors of up to 500-fold were obtained. In this work, determination of analytes partition coefficients in three-phase HF-LPME has been successfully achieved. This study found that the partition coefficient (Ka/d) values were high for 2-nitrophenol and 3-nitrophenol and the individual partition coefficients (Korg/d and Ka/org) promoted efficient simultaneous extraction from the donor through the organic phase and further into the acceptor phase. Both methods were successfully applied for the analysis of water samples.
format Thesis
author Zainal Abidin, Nurul Auni
author_facet Zainal Abidin, Nurul Auni
author_sort Zainal Abidin, Nurul Auni
title Phase equilibrium and partition coefficient of selected pesticides and nitrophenols in double and triple-phase liquid-phase microextraction
title_short Phase equilibrium and partition coefficient of selected pesticides and nitrophenols in double and triple-phase liquid-phase microextraction
title_full Phase equilibrium and partition coefficient of selected pesticides and nitrophenols in double and triple-phase liquid-phase microextraction
title_fullStr Phase equilibrium and partition coefficient of selected pesticides and nitrophenols in double and triple-phase liquid-phase microextraction
title_full_unstemmed Phase equilibrium and partition coefficient of selected pesticides and nitrophenols in double and triple-phase liquid-phase microextraction
title_sort phase equilibrium and partition coefficient of selected pesticides and nitrophenols in double and triple-phase liquid-phase microextraction
publishDate 2009
url http://eprints.utm.my/id/eprint/11123/1/NurulAuniZainalMFS2009.pdf
http://eprints.utm.my/id/eprint/11123/
_version_ 1643645592158601216
score 13.211869

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