Abstract: In this paper, a high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed to determine the contents of α-lactalbumin, β-lactoglobulin and lactoferrin in milk and infant formula. The sample was dissolved with ultrapure water, and reacted with dithiothreitol and iodoacetamide to open disulfide bonds and simultaneously protect sulfhydryl groups before being hydrolyzed with trypsin. After completion of the reaction, aqueous acetonitrile was used for making up to a constant volume, and then centrifugation was carried out to take the supernatant for quantification by external standard method. The results showed that the calibration curves for all analytes were linear in the range of 0–100 μg/mL, with correlation coefficient (r) greater than 0.995. The average recoveries of the analytes from spiked raw milk were 93.5%–117.1%, with relative standard deviation (RSD) ranging from 1.4% to 6.7%. In conclusion, the method was simple, rapid and sensitive, and could be used for the determination of α-lactalbumin, β-lactoglobulin and lactoferrin in milk and milk powder samples.

Key words: high performance liquid chromatography-tandem mass spectrometry, α-lactalbumin, β-lactoglobulin, lactoferrin, milk

摘要： 建立高效液相色谱-串联质谱法测定牛乳和婴幼儿配方乳粉中α-乳白蛋白、β-乳球蛋白和乳铁蛋白含量的方法。样品中加入超纯水溶解，经过二硫苏糖醇和碘代乙酰胺溶液反应打开二硫键并保护巯基后，加入胰蛋白酶溶液进行酶解，反应结束后用乙腈水溶液定容，离心，移取上清液待测，外标法定量。结果表明：α-乳白蛋白、β-乳球蛋白和乳铁蛋白标准曲线在0～100 μg/mL范围内线性良好，相关系数均大于0.995；α-乳白蛋白、β-乳球蛋白和乳铁蛋白在生乳中的平均加标回收率为93.5%～117.1%，相对标准偏差为1.4%～6.7%。该方法前处理操作简便，分析速度快，灵敏度高，可用于牛乳和乳粉中α-乳白蛋白、β-乳球蛋白和乳铁蛋白含量测定。

关键词: 高效液相色谱-串联质谱法, α-乳白蛋白, β-乳球蛋白, 乳铁蛋白, 牛乳