饮用水中多种有机磷农药残留的气相色谱-三重四极杆质谱测定法

目的建立一种同时测定饮用水中7种有机磷农药残留量的气相色谱-三重四极杆质谱（GC-MS/MS）方法。方法采用液-液萃取方法,用二氯甲烷对水样中7种有机磷农药进行提取,无水硫酸钠脱水,滤液在40℃水浴中旋转蒸发近干,用二氯甲烷定容,GC-MS/MS测定,外标法定量。结果 7种有机磷农药在21 min内分离,在0.01-10 mg/L范围内相关系数r2均在0.99以上,在0.05、0.25和0.45 mg/L 3个水平加标回收率在78.9%-99.3%之间,相对标准偏差均小于10%,检出限为0.02-0.06μg/L。结论该方法操作简单,准确度和精密度高,消除了其他有机磷农药的干扰,避免假阳性的出现,适用于饮用水中7种有机磷农药残留量的检测和确证。

Determination of several organophosphorous pesticide residues in drinking water by gas chromatography /tandem mass spectrometry

[Objective]To establish a method for simultaneous determination of 7 organophosphorous pesticide residues in drinking water by gas chromatography /tandem mass spectrometry（ GC-MS /MS）. [Methods]The organophosphorous pesticide residues in drinking water samples were extracted with liquid-liquid extraction,and were dewatered with sodium sulfate. The extract was warmed with water at 40 ℃,cicumrotated and evaporated until it was nearly dry. The methylene chloride was applied in constant volume. The extract was determined by GC-MS /MS,and the quantification was performed by the external standard method.[Results]7 kinds of organophosphorous pesticides were separated within21 minutes. In range of 0.01-10 mg/L,the correlation coefficients（r2） were higher than 0.99. At the concentration of 0.05 mg/L,0.25 mg/L and 0.45 mg/L,the recovery of standard addition was between 78. 9% and 99. 3%. The relative standard deviations（RSD） were lower than 10%,and the detection limit was 0. 02-0. 06 μg /L.[Conclusion]The method is simple,and has higher accuracy and precision. The method can eliminate the interference from other organophosphate pesticides,to avoid false positive results. It is suitable for the detection and confirmation of organophosphorus pesticide residues in drinking water.