固相萃取-气相色谱法测定茶叶中甲氰菊酯含量的不确定度评定

Evaluation of Uncertainty in the Determination of Fenpropathrin in Tea by Solid Phase Extraction Gas Chromatography

对固相萃取-气相色谱法测定茶叶中甲氰菊酯含量进行不确定度评估。运用固相萃取-气相色谱法对茶叶中甲氰菊酯含量进行测定,通过建立数学模型,确立测量过程中不确定度的分量及来源,计算合成标准不确定度和扩展不确定度。结果表明:不确定性的主要来源是甲氰菊酯标准工作曲线、重复测量、固相萃取过程、ECD检测器和标准溶液配置等;当茶叶中甲氰菊酯含量为0.60 mg/kg时,扩展不确定度为0.040 mg/kg(k=2)。该模型为固相萃取-气相色谱法测定茶叶中甲氰菊酯含量的不确定度分析提供科学依据。

To evaluate the uncertainty in the fenpropathrin determination in tea by solid phase extraction gas chromatography.A mathematical model was developed to establish the components and sources of indeterminacy in the measurement process and to calculate the synthetic standard and extended indeterminacy.The primary sources of uncertainty were the standard working curve for alpha-cypermethrin,repeated measurements,the solid phase extraction process,the ECD detector,and the criteria solution configuration.The extended uncertainty was 0.040 mg·kg-1(k=2)when the content of alpha-cypermethrin in tea was 0.60 mg·kg-1.The model provides a scientific and reliable basis for the uncertainty analysis of the determination of alpha-cypermethrin in tea by solid phase extraction-gas chromatography.