气相色谱-火焰光度法测定土壤中有机磷农药残留

Research on Organophosphorus Pesticide Residues in Soil by GC-FPD

土壤样品用正己烷-丙酮(体积比为1∶1)混合溶液提取,配合硅胶小柱净化,用乙酸乙酯洗脱,再用气相色谱-火焰光度法测定待测液中14种有机磷农药残留,方法在0.100 mg/L^1.00 mg/L范围内线性良好,当取样量为10 g时,方法检出限为1.3μg/kg^2.3μg/kg。用该方法测定有机磷的有证标准溶液,结果均在保证值范围内,RSD为2.2%~6.7%。实际土壤样品的13种有机磷农药加标回收率为59.2%~125%(敌百虫除外),敌百虫回收率为0,说明目标物在测定过程中被降解,该方法不适用于敌百虫的测定。

A method was established for detection of 14 organophosphorus pesticide residues in soil by GCFPD. Samples were extracted by n-hexane: acetone( 1 ∶ 1),followed by silica gel column cleanup with ethyl acetate as elution solvent. The method showed good linearity in the concentration range of 0. 100 mg / L ~1. 00 mg / L. The detection limits were 1. 3 μg / kg ~ 2. 3 μg / kg when the sampling weight was 10 g. A certified standard solution of organophosphorus pesticides was determined by this method,the results were within the guarantee values and the RSDs were 2. 2% ~ 6. 7%. The spiked recoveries of 13 organophosphorus pesticides in soil were between 59. 2% and 125%,but the recovery rate of trichlorfon was zero,which indicated that degradation happened in the process. So the method was not suitable for the determination of trichlorfon.