UPLC-MS/MS法测定猪肉和牛肉中褪黑素残留量OA

To monitor the residue levels of melatonin in pork and beef,an analytical method based on ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS)was established.Samples were extracted with 1%(V/V)ammonia water in ethyl acetate and purified by n-hexane degreasing.Chromatographic separation was performed on a Atlantis T3 column(2.1 mm×50 mm,1.8 μm)using a mobile phase consisting of 0.1%(V/V)formic acid in water and acetonitrile,achieving baseline separation of the target compound within 4 min.Detection was carried out using electrospray ionization in positive ion mode(ESI+)and multiple reaction monitoring(MRM).The results demonstrated that melatonin exhibited good linearity in the concentration range of 1.00～100 μg/L,with correlation coefficients≥0.99.The limit of detection was 0.5 μg/kg and the limit of quantification was 1.0 μg/kg.The average recoveries at spiked levels ranged from 64.6%to 91.5%,with relative standard deviations between 0.85%and 6.70%.This study provides technical support for the safety monitoring of livestock meat products.