Yarita Takashi, Otake Takamitsu, Aoyagi Yoshie, Numata Masahiko, Takatsu Akiko
National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST).
Anal Sci. 2016;32(5):557-80. doi: 10.2116/analsci.32.557.
Proficiency testing was organized by the National Metrology Institute of Japan (NMIJ) as a measure of analytical competency in the quantification of pesticide residues in husked wheat powder. Seventy-one participants submitted analytical concentrations of the target pesticides (diazinon, fenitrothion, malathion, and etofenprox) along with details of the analytical method employed. Two types of assigned values were obtained for each target pesticide, i.e., the participants' analytical results and the results obtained by NMIJ based on isotope-dilution mass spectrometry (IDMS). The former values were lower than the latter due to the incomplete recovery yield of the target pesticides during the pretreatment process. The discrepancy between the two assigned values was particularly pronounced for malathion because of the longer duration of water-soaking used for the test samples. Two corresponding types of z-scores were then calculated to evaluate the analytical performance of the participants, where the z1-score indicates the performance of a participant relative to all participants, and the z2-score indicates the relative deviation of the analytical results of the participant from the IDMS value.
日本国家计量院（NMIJ）组织了能力验证，以衡量糙米粉末中农药残留量定量分析的能力。71名参与者提交了目标农药（二嗪农、杀螟硫磷、马拉硫磷和乙螨唑）的分析浓度以及所采用分析方法的详细信息。每种目标农药获得了两种类型的指定值，即参与者的分析结果和NMIJ基于同位素稀释质谱法（IDMS）获得的结果。由于预处理过程中目标农药的回收率不完全，前者的值低于后者。马拉硫磷的两种指定值之间的差异尤为明显，这是因为测试样品的水浸时间较长。然后计算了两种相应类型的z分数，以评估参与者的分析性能，其中z1分数表示参与者相对于所有参与者的性能，z2分数表示参与者的分析结果相对于IDMS值的相对偏差。
