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Liquid-phase Microextraction and Gas Chromatography-mass Spectrometry for the Analysis of Pesticides Residues in the Environment

Author: ChenLiHua
Tutor: ZhangZhanEn
School: Suzhou Institute of Technology
Course: Environmental Engineering
Keywords: Hollow fiber liquid phase microextraction GC-MS Solid samples Triazole fungicides Diphenyl ether herbicides Phthalate plasticizers
CLC: X830
Type: Master's thesis
Year: 2010
Downloads: 69
Quote: 0
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Abstract


Hollow-fiber protected liquid-phase microextraction (HF-LPME) was develeped based on the hanging drop liquid-phase microextraction (HD-LPME). The microdrop suspended on the needle of microsyringe is easily dislodged by the stirred sample solution. The extration solvent is in a porous polypropylene hollow fiber which does not contact with sample solution, so solve the afore mentioned problems; HF-LPME also provide higher richment factor, even a very sample size can achieve good results; In addition, fiber is a one-time use which can avoid cross-contamination problems exist in the extration process. As large molecules, particles impurities can not through fiber-wall, the HF-LPME also has a prominent sample purification function, expanding the scope of analysis substrate, it can be used for the analysis of complex samples. So far HF-LPME has been accounts for numerous reports in a wide range of applications, it has not been only applied to biological, environmental sample testing also has been successfully promoted in food health industry. In this present study, we use the specific advantages of HF-LPME to study two aspects as follows:1. Based on gas chromatography–mass spectrometry (GC-MS) approach, hollow-fiber protected liquid-phase microextraction (HF-LPME) was selected for the extraction of targets in solid samples. A new method for the rapid and direct measurement of triazole fungicides residue in fruits and vegetables was developed.The optimum extraction conditions was investigated: cyclohexane was selected as extract agent, solid samples/water ratio was 1:3(with a total quality 10g), solid samples were extracted at 40°C for 20min with a 500 rpm stirring rates after ultrasonic 5mins. After extraction, 1ul organic solvent was injected into GC-MS for separation and detection. Under the optimum conditions, linear range was between 0.5~25mg/kg, the limits of detection (LOD) were between 0.05～0.500 mg/kg, the relative standard deviation(R.S.D) ranged from 4.7% to 13.2%.2. In this work, hollow-fiber protected liquid-phase microextraction (HF-LPME) gas chromatography–mass spectrometry(GC -MS) approach was selected for the fast measurement of diphenylether and diphenyl-ether herbicides in soil. Cyclohexane functioned as both the extraction solvent and the impregnation solvent. Some important extraction parameters, such as water/ soil ratio, ultrasonic time, extration time, extration temperature and stirring rate were optimized. Under the optimum conditions, the limits of detection (LOD) were between 0.05 and 0.1 mg/kg with GC–MS analysis under selected-ion monitoring (SIM). Also, this method provided good precision ranging from 4.3% to 8.1%. Finally, this method was applied to analysis diphenylether and diphenyl-ether herbicides in practical soil which obtained from a relocation pesticide factory. The analyte was above the limits of detection. The results demonstrated that LPME was a fast and accurate method to determine trace amounts of diphenylether and diphenyl-etherherbicides in soil.3. Based on the above-mentioned experiment, examined the feasibility of hollow-fiber protected liquid-phase micro-extraction gas chromatography-mass spectrometry determination phthalate plasticizers residual in soil samples. Under the optimum conditions, the limits of detection (LOD) of five phthalate plasticizers can reach 0.00049 mg/kg, the linear range was between 0.05~5mg/kg, the relative standard deviation(R.S.D) was below 9.6%.The above experiments show that hollow-fiber protected liquid-phase micro-extraction technology can be used directly for solid sample pre-treatment, this method is fast, simple, inexpensive, pollution-free, and has good extraction result

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