衬管和溶剂选择对气相色谱法测定水中有机磷农药的影响

Influences of selection of liners and solvents to the determination of organophosphorus pesticides in water by gas chromatography

选择不同气相色谱仪衬管,考察其对精密度的影响,确立了使用衬管的类型。选择二氯甲烷、三氯甲烷、丙酮-正己烷(1:1)、乙酸乙酯4种不同溶剂配制5种有机磷农药标准溶液,考察其精密度,确立了最佳使用溶剂。分别以二氯甲烷、三氯甲烷为萃取溶剂,萃取水中的5种有机磷农药,考察不同萃取溶剂对萃取效率的影响。同时考察了不同萃取溶剂体积对萃取效率的影响。结果表明,使用安捷伦5190-5112-005高惰性不分流直型衬管能得到更好的精密度。使用乙酸乙酯作为溶剂配制标准溶液,5种有机磷农药的相对标准偏差较低,具有更高的精密度和重复性。加标回收实验表明,萃取溶剂宜使用三氯甲烷,在100mL水样中,萃取溶剂体积以10mL为宜。

The types of gas chromatograph liners used were determined by investigated the influences to the method precisions.Five organophosphorus pesticide standard solutions were prepared with four different solvents:dichloromethane,chloroform,acetone-n-hexane(1:1)and ethyl acetate.The precision of the solutions was investigated and the best solvent was determined.Five organophosphorus pesticides in water were extracted with dichloromethane and chloroform as extraction solvents,and the influences of different extracting solvents to extraction efficiency were investigated.At the same time,the influences of different volumes of extracting solvents to the extraction efficiencies were investigated.The results showed that better precision could be obtained by using Agilent 5190-5112-005 high inert straight liner.Using ethyl acetate as a solvent to prepare standard solution had higher precisions because of the relative standard deviation of the five organophosphorus pesticides using ethyl acetate as solvent were low.By the standard adding recovery experiments,Chloroform should be used as the extracting solvent and the volume of extracting solvent should be 10ml when the water sample is 100ml.