The research aims to develop a rapid and easy analytical method for methoprene using liquid chromatography- tandem mass spectrometry (LC-MS/MS). A simple, highly sensitive, and specific analytical method for the determination of methoprene in livestock products (beef, pork, chicken, milk, eggs, and fat) was developed. Methoprene was effectively extracted with 1% acetic acid in acetonitrile and acetone (1:1), followed by the addition of anhydrous magnesium sulfate (MgSO4) and anhydrous sodium acetate. Subsequently, the lipids in the livestock sample were extracted by freezing them at -20oC. The extracts were cleaned using MgSO4, primary secondary amine (PSA), and octadecyl (C18), which were then centrifuged to separate the supernatant. Nitrogen gas was used to evaporate the supernatant, which was then dissolved in methanol. The matrix-matched calibration curves were constructed using 8 levels (1, 2.5, 5, 10, 25, 50, 100, 150 ng/mL) and the coefficient of determination (R2) was above 0.9964. Average recoveries spiked at three levels (0.01, 0.1, and 0.5 mg/kg), and ranged from 79.5-105.1%, with relative standard deviations (RSDs) smaller than 14.2%, as required by the Codex guideline (CODEX CAC/GL 40). This study could be useful for residue safety management in livestock products.

짚시나방(Lymantria dispar)의 배자 발생에 미치는 유약호르몬의 영향을 조사하기 위하여 유약호르몬 유사체인 methoprene을 알에 도포처리(topical treatments)하여 부화율, 부화 유충의 생체량 및 알의 단백질과 탄수화물 함량 변화를 조사하였다. Methoprene 농도별 처리는 부화율에 영향을 미쳐 methoprene 처리군이 대조군(78.5%)에 비해 낮은 부화율을 나타 냈으며 5.0 처리군에서 가장 낮은율(42.5%)을 보여 주었다. 부화 직후 1령 유충의 생체량은 대조군이 0.7525mg으로 가장 높았으며 methoprene 농도 처리 순으로 감소하다가 5.0 처리군에서 0.6487mg으로 최하치를 나타냈다. 처리군별로는 대조군과 0.5 처리군이, 1.0와 2.0 처리군의 생체량이 유사하였다. 배자 발생중 알의 단백질 함량 변화에서 0.5 처리군은 2, 4일째 대조군과 뚜렷한 차이를 나타냈으며, 탄수화물도 대조군에 비해 처리군이 낮은 함량을 유지하였다.