乙酰甲胺磷在水中消解和残留动态研究

Study on Residue Analysis and Degradation of Acephate in Water

研究了乙酰甲胺磷在水中残留的气质联用分析方法及乙酰甲胺磷在pH5、pH7、pH9缓冲溶液中的消解和残留动态。样品以丙酮和二氯甲烷提取,经无水硫酸钠干燥,浓缩、定容后,用气相色谱质谱联用的选择离子方式(GC/MS-SIM)进行定性、定量分析。乙酰甲胺磷的最小检出量为0.05ng,水样中的最低检出浓度为0.005mg/L,添加回收率为90.1%～98.4%,相对标准偏差在0.89%～4.31%,符合残留分析要求。用该方法测定了乙酰甲胺磷在不同pH缓冲溶液中的消解动态,结果表明,乙酰甲胺磷在水中的降解与水的pH有关,碱性水中乙酰甲胺磷降解较快,酸性水中降解较慢,其在pH5、pH7、pH9水中的降解半衰期分别为130.8、34.8、9.3d。

A GC-MS/SIM method was developed to determine residue of acephate in water. The degradation of acephate in pH5, pH7, pH9 water were studied as well.Residues of acephate were extracted from water by acetone and dichloromethane, dried by Na2SO4 and determined by GC-MS/SIM. The lowest detection limit of instrument for acephate was 0.05ng, The lowest detection concentration for sample was 0.05 mg/L.The average recovery and RSD. of this method were 90.1%-98.4% and 0.89%-4.31%. The results showed that the degradation rate of acephate in water was relative with the pH, which degraded rapidly in alkaline water and slowly in acidic water. The half-life values of acepllate in the pH5, pH7, pH9 water were 130.8, 34.8 and 9.3 days, respectively.