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以一碘酪氨酸(MIT)和二碘酪氨酸(DIT)为标志物,建立了奶牛配合饲料中碘化酪蛋白(IC)的LC-MS/MS监测方法。样品经Ba(OH)2水解,IC释放MIT和DIT,再经Cleanert PAX小柱净化,ZORBAX Eelipse XDB-C18(3.5μm,2.1×150 mm)柱,0.1%乙酸水溶液(V/V)和甲醇为流动相,梯度洗脱分离,正电喷雾质谱多重反应监测(MIT:308.0>262.0,308.0>135.2.0;DIT:433.8>387.4,433.8>289.5)。通过对样品水解液中MIT、DIT的定性、定量分析及建立DIT与IC的定量关系,实现了对IC的监测,IC最低检出水平不大于20 mg/kg;在20～1000 mg/kg的范围内IC的回收率为85.0%～128.5%,相对标准差为4.6%～17%。
Using iodine tyrosine (MIT) and diiodotyrosine (DIT) as markers, LC-MS / MS monitoring method of iodinated casein (IC) in dairy cows was established. The sample was hydrolyzed with Ba (OH) 2, and the IC released MIT and DIT. The sample was then purified on a Cleanert PAX cartridges using a ZORBAX Ellipse XDB-C18 column (3.5 μm, 2.1 × 150 mm), 0.1% acetic acid in water (MIT: 308.0> 262.0, 308.0> 135.2.0; DIT: 433.8> 387.4, 433.8> 289.5) were used as mobile phase, gradient elution and electrospray ionization mass spectrometry. The qualitative and quantitative analysis of MIT and DIT in the sample hydrolyzate and the quantitative relationship between DIT and IC were carried out to monitor the IC. The minimum detection level of IC was not more than 20 mg / kg. In the range of 20 ~ 1000 mg / kg Within the range of IC recovery rate of 85.0% ~ 128.5%, the relative standard deviation of 4.6% to 17%.