【摘要】 目的:评定气相色谱法测定茶鲜叶中氯氰菊酯、氰戊菊酯和溴氰菊酯3种拟除虫菊酯农药残留量的不确定度。方法:通过建立数学模型，分析测定过程中的不确定度来源，包括样品测定重复性、标准曲线拟合、添加回收率、标准溶液配制、样品称量和前处理、仪器测定等，并对其进行量化、合成与扩展。结果:在0.10 mg/kg添加水平下，氯氰菊酯、氰戊菊酯、溴氰菊酯的扩展不确定度分别为0.011,0.011,0.012 mg/kg,当置信概率为95%(k=2)时，测定结果可表示为：氯氰菊酯(0.093±0.011) mg/kg,氰戊菊酯(0.094±0.011) mg/kg,溴氰菊酯(0.098±0.012) mg/kg。结论:该方法主要不确定来源为标准溶液配制、标准曲线拟合及回收率，提示样品检测过程中需对这几个方面进行严格控制。更多还原

【Abstract】 Objective: The uncertainty of determination of three pyrethroid pesticides(cypermethrin, fenvalerate and deltamethrin) in fresh tea leaves by gas chromatography was evaluated. Methods: A mathematical model was established according to the determination process of the experiment, and the uncertainties caused by various factors in the model were identified. The sources are mainly the following 7 aspects: repeated determination of samples, fitness of standard curve, recovery rate, standard solution preparation, sample weighing and pretreatment, and the measurement of instrument. Results: At the spiking level of 0.10 mg/kg, the expanded uncertainty of measured values of cypermethrin, fenvalerate, and deltamethrin were 0.011, 0.011 and 0.012 mg/kg, respectively. The detection results of three pesticides in fresh tea leaves in 95% confidence interval could be expressed as cypermethrin:(0.093±0.011) mg/kg, fenvalerate:(0.094±0.011) mg/kg, deltamethrin:(0.098±0.012) mg/kg(k=2). Conclusion: The uncertainties of the method were mainly introduced by standard solution preparation, calibration curve fitting and recovery rate, indicating that these aspects should be controlled strictly in the following sample analysis.更多还原