Abstract: A quick confirmative method for the determination of residual amounts of 11 anabolic hormones and 9 agonists in milk and milk powder by liquid chromatography-tandem mass spectrometry (LC-MS-MS) was developed. Samples were extracted with acetonitrile containing 0.1% formic acid by volume. After lipid removal by liquid-liquid extraction with n-hexane, the purification of the extract was carried out on an Oasis HLB cartridge by solid-phase extraction. The analytes were separated on a C8 column employing a mobile phase composed of a mixture of methanol with 0.1% formic acid and 0.1% formic for gradient elution. The tandem mass spectral acquisition was done in the positive electrospray ionization mode utilizing multiple reaction monitoring. External standard method was applied for quantization. The results indicated that the limits of quantification (LOQs, RSN = 10) for 20 target compounds ranged from 0.1 to 1.0 μg/kg, and the linear range was 0.05–50 μg/L with correlation coefficients larger than 0.996. The average recoveries at different spiked concentration levels ranged from 52.8% to 97.4% with RSD of 2.8%–9.6% (n = 6). The proposed method has been applied for the rapid determination of real samples of milk and milk powder with simple operation and accurate results.

Key words: liquid chromatography-tandem mass spectrometry (LC-MS-MS); anabolic hormones; β-agonists; milk; milk powder

摘要： 建立了液相色谱-电喷雾串联质谱同时测定乳与乳粉中11种甾类和9种β-受体激动剂类同化激素的快速确证方法.样品经体积分数0.1％甲酸乙腈溶液提取,正己烷脱脂,HLB固相萃取柱净化后,以0.1％甲酸甲醇-0.1％甲酸水为流动相梯度洗脱,通过C8色谱柱分离,电喷雾正离子多反应监测模式检测.在优化条件下,20种目标物在0.05～50 μg/L范围内线性良好,相关系数均大于0.996;方法定量限(RSN=10)在0.1～1.0 μg/kg之间;不同添加水平回收率为52.8％～97.4％,相对标准偏差(n=6)为2.8％～9.6％.多种市售纯牛奶和乳粉的测定结果表明,该方法操作简单、测定结果准确,可用于乳与乳粉中甾类和β-受体激动剂类激素多残留的快速测定.

关键词: 液相色谱-电喷雾串联质谱；甾类；β-受体激动剂；乳；乳粉