A liquid chromatography-tandem mass spectrometry(LC-ESI-MS/MS)method for the determination of melamine and its analogues (CYA, AMD, AMN) in feeds & soils was reported. The analytes were extracted with the soluction (V(2. 5% formic acid) : V(aceto-nitrile) = 50 : 50) from matrix, and then the extracting solution was evaporated by nitrogen blow, dissolved in the soluction (V(0. 2% formic acid) : V(acetonitrile) = 10 : 90) and assayed by LC-MS/MS. The chromatographic retention time and mass fragment ion abundances ratio for qualitative, and with 15N3-melamine, 13C3-cyanuric acid as internal standard for quantitative. Scanning of positive ions and negative ion scan the instrument method studies, to determine the abundance ratio of the highest two pairs of ions as monitoring ion MRM mode for qualitative and quantitative analysis. The limit of detection (LOD) is 0. 25-0. 50 mg/kg. The correlation coefficient is greater than 0. 999 within the linear range of 5.0-500.0 μg/L. Recoveries of MEL, CYA, AMD and AMN are 61. 4% -115%, and the relative standard deviation is less than 12. 6% at spiked levels of 0. 5-2. 0 mg/kg (n =5).%采用高效液相色谱-电喷雾串联质谱(LC-ESI-MS-MS)在多反应监测(MRM)模式下,建立饲料和土壤中三聚氰胺及其类似物(三聚氰酸、三聚氰酸一酰胺、三聚氰酸二酰胺)的快速确认检测方法.试样中的三聚氰胺及其类似物经甲酸-乙腈溶液提取,氮气吹干,用定容液溶解后,进行液相色谱-串联质谱测定,采用色谱保留时间和质谱碎片离子丰度比定性,以15N3-三聚氰胺、13C3-三聚氰酸作为内标进行定量.采用正离子扫描和负离子扫描的方式进行仪器方法学研究,确定丰度比最高的两对离子作为监测离子,进行MRM模式定性定量分析.该方法的检出限(LOD)为0.25～0.50 mg/kg;在5.0～500.0 μg/L的线性范围内,相关系数r均大于0.999.在0.5～2.0 mg/kg的添加水平上,三聚氰胺、三聚氰酸、三聚氰酸一酰胺和三聚氰酸二酰胺的回收率为61.4％～115％,相对标准偏差不大于12.6％.
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