Objective To establish a method for detection of acephate and methamidophos by gas chromatography-mass spectrometry (GC-MS).Methods The temperature program of GC was optimized and determined by orthogonal experiment, and pesticides were extracted from aqueous solution by liquid-liquid extraction. In addition, the recovery rates of extraction from aqueous solution were corrected by matrix-matched standard calibration.Results The temperature program used first order temperature programming as follows: the temperature of column was from 95℃ to 280℃ at a speed of 10℃/min,.The inert liner was inert. Under the optimized conditions, the average recoveries of the method ranged from 80.3% to 110.5% at the spiked levels of 0.1~1 mg/L with the relative standard deviations of 5.5%~6.5%. Acephate and methamidophos had good linear relationship in the range of 0.01~0.5 mg/L (r2>0.999), the limits of detection (LODs) were 0.02 mg/L and 0.008 mg/L, and the limits of quantitation (LOQs) were 0.066 mg/L and 0.027 mg/L for acephate and methamidophos, respectively.Conclusion The established method had good precision, repeatability and stability, which can be applied to the detection of acephate and methamidophos.%目的 建立气相色谱-质谱法(gas chromatography-mass spectrometry,GC-MS)同时检测乙酰甲胺磷和甲胺磷的残留量.方法 通过正交试验优化并确定升温程序参数,利用液液萃取方法从水中提取乙酰甲胺磷及甲胺磷后,采用基质匹配标准溶液对两种农药的回收率进行校准.结果 升温程序应采用一阶程序升温,初始温度为95℃,升温速度为10℃/min,末温为280℃;进样口采用惰性衬管;添加水平为0.1~1 mg/L时,回收率在80.3%~110.5%之间,相对标准偏差在5.5%~6.5%之间.乙酰甲胺磷和甲胺磷在用纯溶剂(丙酮)和空白基质配制0.01~0.5 mg/L浓度范围内线性关系良好(r2>0.999),乙酰甲胺磷和甲胺磷的检出限分别为0.02 mg/L、0.008 mg/L,定量检测分别为0.066 mg/L、0.027 mg/L.结论 该方法的精密性、重复性和稳定性良好,可适用于乙酰甲胺磷和甲胺磷残留量的检测.
展开▼
