Yarita Takashi, Otake Takamitsu, Aoyagi Yoshie, Kuroda Youko, Numata Masahiko, Iwata Hitoshi, Watai Masatoshi, Mitsuda Hitoshi, Fujikawa Takashi, Ota Hidekazu
National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 3, Umezono, Tsukuba, Ibaraki 305-8563, Japan.
National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 3, Umezono, Tsukuba, Ibaraki 305-8563, Japan.
Talanta. 2014 Feb;119:255-61. doi: 10.1016/j.talanta.2013.11.011. Epub 2013 Nov 11.
A soybean certified reference material for pesticide residue analysis was developed by the National Metrology Institute of Japan. Three organophosphorus (diazinon, fenitrothion, chlorphyrifos) and one pyrethroid (permethrin) pesticides were sprayed on soybeans three times before harvest. These soybeans were freeze pulverized, homogenized, bottled, and sterilized by γ-irradiation to prepare the candidate material. Three isotope-dilution mass spectrometric methods that varied in terms of the solvents used for extraction of the target pesticides, the clean-up procedure, and the injection techniques and columns used for quantification via gas chromatography/mass spectrometry were applied to the characterization. Each target pesticide was quantified by two of these analytical methods, and the results were in good agreement. Homogeneity and stability assessment of the material demonstrated that the relative standard uncertainties due to the inhomogeneity and the instability for an expiry date of 55 months were 1.89-4.00% and 6.65-11.5%, respectively. The certified pesticide concentrations with expanded uncertainties (coverage factor k=2, approximate 95% confidence interval) calculated using the results of the characterization and the homogeneity and stability assessment were 21.7 ± 3.2 μg/kg for diazinon, 88 ± 21 μg/kg for fenitrothion, 11.1 ± 3.2 μg/kg for chlorpyrifos, and 20.1 ± 4.3 μg/kg for permethrin (as the sum of the constituent isomers).
日本国家计量院研制了一种用于农药残留分析的大豆标准参考物质。在收获前，将三种有机磷农药（二嗪农、杀螟硫磷、毒死蜱）和一种拟除虫菊酯类农药（氯菊酯）分三次喷洒在大豆上。这些大豆经过冷冻粉碎、均质化、装瓶，并通过γ射线辐照进行灭菌，以制备候选物质。应用了三种同位素稀释质谱法对其进行特性描述，这三种方法在目标农药提取所用溶剂、净化程序以及气相色谱/质谱法定量所用的进样技术和色谱柱方面存在差异。每种目标农药均通过其中两种分析方法进行定量，结果吻合良好。对该物质的均匀性和稳定性评估表明，对于55个月的有效期，由不均匀性和不稳定性导致的相对标准不确定度分别为1.89 - 4.00%和6.65 - 11.5%。利用特性描述结果以及均匀性和稳定性评估计算得出的具有扩展不确定度（包含因子k = 2，近似95%置信区间）的农药认证浓度分别为：二嗪农21.7 ± 3.2 μg/kg、杀螟硫磷88 ± 21 μg/kg、毒死蜱11.1 ± 3.2 μg/kg、氯菊酯20.1 ± 4.3 μg/kg（作为各组成异构体之和）。
