Applications On Dispersive Liquid-liquid Microextration For Determination Of Triazole Pesticides

Dispersive liquid-liquid microextraction（DLLME）is a simple,fast,and miniaturized sample preparation technique,which incorporates sampling,extraction and enrichment into one step.A good number of works have been reported about the determination of a vast variety of organic and inorganic compounds in different matrices since its introduction in 2006.The purpose of this study was to develop novel alternatives of dispersive liquid-liquid microextraction coupled with GC-MS to analysis of triazole pesticides in different matrices.A brief description was given as follows:（1）A simply overview about the principles,improvements of the type of extraction solvent,the mode of dispersion,the way of demulsification and application of organic compounds by DLLME;Besides,the development of triazole pesticides was also illustrated.（2）A dissolved carbon dioxide flotation after emulsification microextraction（DCF-EME）method was proposed for determination of four triazole pesticides in water samples coupled with gas chromatography-mass spectrometry（GC-MS）in a glass round flask.DCF-EME 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 HCO₃ solution into the acidified sample solution(0.1 mol·L^-1 HCl)containing analytes.Various parameters affecting the extraction process were optimized.The results of the analysis revealed that this method is simple,fast and environmentally friendly,being successfully applicable for the determination of triazole pesticides in water samples.（3）A novel method of Qu ECh ERS（quick,easy,cheap,effective,rugged and safe）combined with polyethylene pasteur-pipette-based dispersive liquid-liquid microextraction（DLLME）applying low-density solvent was proposed for determination of eleven triazole pesticides in fruit juices（apple juice,grape juice and pear juice）coupled with gas chromatography-mass spectrometry（GC-MS）.DLLME technique was applied for extraction and preconcentration of pesticide residues from Qu ECh ERS extract.A low density solvent（toluene）was used as extraction solvent instead of chlorinated solvents,and a cheap and disposable polyethylene pasteur pipette was employed as a vessel for extraction,preconcentration,and collection of target analytes.Various parameters affecting the extraction process were optimized.The results of the analysis revealed that this method is simple,fast and environmentally friendly,being successfully applicable for the determination of triazole pesticides in juice samples.（4）A novel method of Qu ECh ERS（quick,easy,cheap,effective,rugged and safe）combined with polyethylene pasteur-pipette-based dispersive liquid-liquid microextraction（DLLME）was proposed for determination of three triazole pesticides in zizania latifolia coupled with gas chromatography-mass spectrometry（GC-MS）.Samples were extracted by acetonitrile with ultrasonic assisted,and then extract was cleaned up by adding PSA and C₁₈ followed by DLLME.A low density solvent（toluene）was used as extraction solvent in DLLME instead of chlorinated solvents,and a cheap and disposable polyethylene pasteur pipette was employed as a vessel for extraction,preconcentration,and collection of target analytes.Various parameters affecting the extraction process were optimized.The results of the analysis revealed that this method is simple,fast and environmentally friendly,being successfully applicable for the determination of triazole pesticides in zizania latifolia.