LC/ESI-MS/MSによる畜水産物中の大環状ラクトン寄生虫駆除剤の一斉分析法

摘要

An LC/ESI (positive-mode)-MS/MS method was developed for simultaneous quantification of 8 macrocyclic lactones (abamectin B1a, abamectin 8,9-Z isomer B1a, emamectin benzoate B1a, emamectin benzoate 8,9-Z isomer B1a, ivermectin, eprinomectin B1a, doramectin and moxidectin) in animal tissues, egg, milk and honey. The separation was achieved on a TSK-GEL ODS 100 V column (2.0×50 mm, 3μm) with a mobile phase consisting of 0.1% formic acid in acetonitrile, and 0.1 mM ammonium formate-0.1% formic acid in water, at a flow rate of 0.2 mL/min with gradient elution. Linear calibration plots were obtained with high correlation coefficients (r= 0.998-0.999). The LOQ and LOD ranged from 0.02-1.5 ng/mL and 0.1-5 ng/mL, respectively. Average recoveries were in the range of 70.8-117.1% with associated RSD values < 15% (n=10) for repeatability and reproducibility. The spiking levels for recoveries and RSDs met the validation criteria for Japanese maximum residue limits (MRLs). Based on these results, the proposed analytical method has been proven to be highly efficient and suitable for routine determinations of macrocyclic lactones in animal food matrices.%LC-ESI/MS/MSを用いて畜水産物（鶏ささ身，牛肉rn（筋肉），牛脂肪，牛肝臓，さけ，うなぎ，しじみ，牛乳，rn鶏卵，はちみつ）中の大環状ラクトン寄生虫昏区除剤（アバrnメクチン，8,9-Z-アバメクチン，エマメクチン，8,9-Z-エrnマメクチン，イベルメクチン，エプリノメクテン，ドラメrnクチン，モキシデクチン）の一斉分析法を開発した．前処rn理法は，試料をアセトン/0.5%アンモニア水でホモジナrnイズし，イソオクタンで抽出した後，n-ヘキサンで脱脂すrnる簡便な手法である．また，マトリックス効果の影響を低rn減化するため，牛肝臓試料のみ希釈倍率の変更を考案しrnた．本手法による回収率，併行精度および室内精度を求めrnた結果，いずれも良好であると判断できた．