Dept. of Environmental and Primary Prevention, Italian National Institute of Health, Rome, Italy.
J Environ Sci Health B. 2012 Sep;47(8):804-13. doi: 10.1080/03601234.2012.676425.
In the analytical analysis the measurement uncertainty is a quantitative indicator of the confidence describing the range around a reported or experimental result within which the true value can be expected. Several approaches can be used to estimate the measurement uncertainty associated to the analysis of pesticide residues: a) the top-down, the estimation can be referred to default values; b) the bottom-up the estimation is related to the uncertainty sources. Concerning the bottom-up approach, the following contributions have been investigated: weight of sample, calibration solutions, final volume of sample and intermediate repeatability studies. The commodity/residue combination selected in this study was celery/tau-fluvalinate pesticide. Tau-fluvalinate is a broad-spectrum insecticide in the pyrethroid class of pesticides. The Maximum Residue Limit (MRL) of tau-fluvalinate in celery has been set at 0.01 mg/kg. The tau- Fluvalinate showed two chromatographic peaks. Since the individual standards are not available, the two peaks were integrated separately and the instrumental responses were added. The total residue was calculated on the basis of resulted peaks. The present work aims to compare the uncertainty estimated by experimental data using repeated analysis (n = 12) of a real sample and a spiked sample. The relative expanded uncertainty for two data set, incurred and spiked, was 22 % and 20 %, respectively. No differences were observed from repeated determinations of real samples and spiked samples.
在分析分析中，测量不确定度是一个定量指标，用于描述报告或实验结果周围的置信区间，在该区间内可以预期真实值。有几种方法可以用于估计与农药残留分析相关的测量不确定度：a）自上而下，估计可以参考默认值；b）自下而上，估计与不确定度来源有关。关于自下而上的方法，已经研究了以下贡献：样品重量、校准溶液、样品最终体积和中间重复性研究。本研究选择的商品/残留组合是芹菜/tau-氟戊菊酯农药。tau-氟戊菊酯是拟除虫菊酯类杀虫剂中的一种广谱杀虫剂。tau-氟戊菊酯在芹菜中的最大残留限量（MRL）设定为 0.01 毫克/千克。tau-氟戊菊酯显示出两个色谱峰。由于没有单独的标准品，因此分别对两个峰进行积分，并将仪器响应相加。根据得到的峰计算总残留量。本工作旨在比较使用实际样品和加标样品的重复分析（n=12）获得的实验数据估计的不确定度。两个数据集（实际和加标）的相对扩展不确定度分别为 22%和 20%。从实际样品和加标样品的重复测定中未观察到差异。
