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The Application of Dispersed Liquid Phase Microextraction Combined with Chromatographic Technique for the Determination of Organic Pollutants

Author: LiuQingLing
Tutor: YeCunLing
School: Henan Normal
Course: Analytical Chemistry
Keywords: Dispersive liquid phase microextraction chromatography environmental water samples
CLC: X830.2
Type: Master's thesis
Year: 2011
Downloads: 35
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Abstract


In the detection of environmental contaminants, sample pretreatment technology plays an important role in the analytical process. Therefore, more and more concern has been paid by analysts to the technology which is simple, quick, free or little solvent and less pollution to environment. The emergence of liquid phase microextraction （LPME） is just a new type of sample pretreatment technique in this case. It can be satisfied with only microliter or even nanoliter organic solvent extraction upgrade which is a combination of extraction and enrichment in one sample preparation and friendly-environment technology with the main principle that to be suspended trace analysis in the injector tip and sample droplets of organic solvent distribution coeffcients between the different liquid-phase microextraction. After nearly ten years of development, LPME have been developed by direct, cycle, headspace, hollow fiber membrane, a single drop, dispersive LPME and ultrasound-assisted emulsification microextraction among which DLPME meet the requirement of the development of modern analytical chemistry with advantages such as less sample and organic solvent, high enrichment factor, no special device, easy to operate, environmentally friendly and so on. Thus, the DLPME technology has a wide range of applications in environmental monitoring, food and bio-medicine and other fields at present.This paper includes two parts: review and research report. The first part is review which expounds the research progress of sample pretreatment technology. The second part is a research report which mainly including four fllowing systems: （1） DLPME combined with high performance liquidchromatography-ultraviolet detection （HPLC-UV） for the determination of three triazole derivatives in environmental water samples. （2） Determination of buprofezin and pyridaben in real water samples using DLPME followed by HPLC. （3） Determination of naphthols in real water samples using DLPME followed by HPLC. （4） DLPME combined with GC-FID for the determination of hypnone derivatives in water.1. DLPME combined with HPLC-UV for the determination of three triazole derivatives in environmental water samplesA simple and efficient method known as DLPME was demonstrated for the extraction of triadimefon, uniconazole and tebuconazole in real water samples prior to HPLC-UV. Several related parameters that could affect the extraction efficiencies were also investigated and optimised. Under the optimum conditions, a linear range was obtained between the peak area and the concentration of the interested analytes over the concentration range of 1.5-100.0μg L-1 for triadimefon, 2.0-100.0μg L-1 for uniconazole and tebuconazole, respectively. The limits of detection （LODs） （S/N=3） values were in the range of 0.9-1.2μg L-1. The intra-day and inter-day precisions for the analysis ranged from 2.8% to 7.6%. The relative recoveries of the three analytes in tap, well and lake water samples were in the range of 90.6%-105.3%. Finally, a comparison of the sensitivity between the proposed DLPME and the improved single-drop microextraction was also evaluated.2. Determination of buprofezin and pyridaben in real water samples using DLPME followed by HPLCA simple and efficient method known as DLPME was demonstrated for the extraction of buprofezin and pyridaben in real water samples prior to HPLC-UV. The effects of relative parameters were investigated in detail. Under the optimum conditions, the linear ranges of buprofezin and pyridaben were 2.0-100.0μg L-1 and 1.0-100.0μg L-1, respectively. The limits of detection were 1.2μg L-1 for buprofezin and 0.6μg L-1 for pyridaben. The relative standard deviations of buprofezin and pyridaben for six repeated determinations were 5.7% and 2.8%, respectively. The method was successfully applied to the determination of trace amounts of buprofezin and pyridaben in tap water, underground water and lake water and the relative recoveries were obtained in the range of 81.27%-100.7%.3. Determination of naphthols in real water samples using DLPME followed by HPLCA simple method using DLPME combined with HPLC-UV has been developed for the extraction and determination ofα-naphthol andβ-naphthol in real water samples. In the proposed method, chlorobenzene was used as extraction solvent and acetone was disperser solvent. The effects of relative parameters were investigated in detail. Under the optimum conditions, the linear ranges ofα-naphthol andβ-naphthol were 1.5-50.0μg L-1 and 1.0-50.0μg L-1, respectively. The limits of detection were 0.9μg L-1 forα-naphthol and 0.5μg L-1 forβ-naphthol. The relative standard deviations ofα-naphthol andβ-naphthol for six repeated determinations were 3.3% and 1.5%, respectively. The method was successfully applied to the determination of trace amounts ofα-naphthol andβ-naphthol in tap water, underground water and lake water and the relative recoveries were obtained in the range of 91.3101.0%.4. DLPME combined with GC-FID for the determination of hypnone derivatives in waterA simple and efficient method known as DLPME was demonstrated for the extraction of hypnone derivatives in real water samples prior to GC-FID. Several related parameters that could affect the extraction efficiencies were also investigated and optimized. Under the optimum conditions, a linear range was obtained between the peak area and the concentration of the interested analytes over the concentration range of 0.5-100.0μg L-1 for hypnone, 0.9-100.0μg L-1 for 2-Hydroxy acetophenone 1.0-100.0μg L-1 for p-bromoacetophenone, 0.73-100μg L-1 for p-acetylanisole and 0.77-100μg L-1 for diphenyl ketone, respectively. The limits of detection （LODs） （S/N=3） values were in the range of 0.3-0.6μg L-1. The relative standard deviations of five hypnone derivatives for six repeated determinations were 5.5%, 8.5%, 5.6%, 7.1% and 2.5%, respectively. The relative recoveries of the five analytes in tap, well, lake and fountain water samples were in the range of 90.2-113.9%.

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CLC: > Environmental science, safety science > Environmental Quality Assessment and Environmental Monitoring > Environmental monitoring > General issues > Monitoring and analysis methods
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