Analysis Method Of Triazole And Pyrethroid Pesticide Residues

With the improvement of people’s awareness of environmental protection and food safety,the monitoring of pesticide residues in environment and food is constantly strengthened at domestic and overseas.Under such circumstances,it is very important to develop sample preparation techniques.Dispersive liquid-liquid microextraction（DLLME）is a novel sample preparation technique,which is simple,efficient,environmentally friendly and miniaturized.It is widely used in the analysis field.With continuous improvement and innovation,scholars put forward various efficient new types of DLLME.Ultrasonic and microwave synergistic extraction（UMSE）,which is a complementary technique involving the coupling of microwave assisted extraction and ultrasonic-assisted extraction,which is quick,easy,efficient and green.The purpose of this study was to develop novel DLLME technique and UMSE technique coupled with gas chromatography-mass spectrometry（GC-MS）respectively to analyze of pesticide residues in food and environmental samples.The main research of the paper is as followings:（1）A overview of the theoretical basis,impact factors and the development of DLLME and UMSE;and a brief introduction of triazole and pyrethroids pesticides.（2）A dissolved carbon dioxide flotation after dispersive liquid-liquid microextraction（DCF-DLLME）method was proposed for determination of sixteen pyrethroids in water samples coupled with GC-MS/MS in a homemade glass round flask.DCF-DLLME method is based on the rapid and simple phase separation of low density organic solvent from the aqueous phase via introducing of a saturated Na HCO₃solution into the acidified sample solution(0.10 mol·L^-1CH₃COOH)containing analytes,under the action of ultrasonic,carbon dioxide gas was generated quickly to accelerate the demulsification.The method break through the limit of volume in centrifugation,and the results of the analysis revealed that this method is simple,fast,high sensitivity and environmentally friendly.（3）A novel method of effervescence-assisted dispersive liquid-liquid microextraction（EA-DLLME）was proposed for determination of four triazole pesticides in water samples coupled with GC-MS.The principle of method is similar with DCF-DLLME,and the reaction of powder composed of sodium dihydrogen phosphate and anhydrous sodium carbonate in water provided CO₂gas,the CO₂gas was applied to demulsifacation.This method,which does not require centrifugation or any special apparatus,is simple,efficient,low toxicity,high extraction efficiency and for field analysis,promising to be a way to speed field sampling procedures for the pesticide residue monitoring in water.（4）Ultrasonic and microwave synergistic extraction technique was proposed for determination of sixteen pyrethroids in bayberry samples coupled with GC-MS/MS.The experiment was carried out in a homemade glass bottle,with low density solvent as the extractant,after adsorbents were added in the bottle.Under the effect of ultrasonic wave and microwave,the pyrethroids in the bayberry was to be extracted.The results showed that UMSE is a high efficient,reproducible and easy to operate method,which can be used to once detection of various pyrethroid residues in bayberry.