Abstract: A method for the determination of α-lactalbumin and β-lactoglobulin in pasteurized milk by high performance liquid chromatography (HPLC) was developed. The sample pretreatment procedure involved sequential water dilution, pH value adjustment to 4.6 for precipitation of casein, and filtration. The subsequent analysis was performed on an Xbridge Protein BEH C4 column using gradient elution with a mobile phase made up of 0.1% (V/V) aqueous trifluoroacetic acid and 0.09% (V/V) aqueous trifluoroacetic acid-acetonitrile. The analytes were detected by an ultraviolet (UV) detector and quantified by an external standard method. The results showed that a good linearity was observed for α-lactalbumin in the concentration range of 10–500 mg/L, with a correlation coefficient of 0.999 87. The recovery of α-lactalbumin spiked at levels of 200 to 1 032 mg/L in milk ranged from 97.9% to 104.0%, and the relative standard deviation (RSD) for precision was 0.00%–1.09%. The linear range for β-lactoglobulin was 20–900 mg/L, with a correlation coefficient of 0.999 96. The recovery of β-lactoglobulin spiked at levels of 600–4 727 mg/L in milk was 96.1%–103.0%, and the precision RSD was 0.00%–2.23%. This method has good separation effect and repeatability and is useful for accurate quantitation of α-lactalbumin and β-lactoglobulin in pasteurized milk.

Key words: pasteurized milk; high performance liquid chromatography; α-lactalbumin; β-lactoglobulin

摘要： 建立巴氏杀菌乳中α-乳白蛋白、β-乳球蛋白的高相液相色谱分析方法。样品经水稀释、调节pH值至4.6沉淀酪蛋白，过滤后采用Xbridge Protein BEH C4柱分析，经体积分数0.1%三氟乙酸-水溶液、体积分数0.09%三氟乙酸-乙腈溶液梯度洗脱、紫外检测器检测、外标法定量。结果表明：α-乳白蛋白在10～500 mg/L质量浓度范围内线性良好，相关系数为0.999 87；当牛乳中α-乳白蛋白加标量为200～1 032 mg/L，加标回收率为97.9%～104.0%、相对标准偏差（relative standard deviation，RSD）为0.00%～1.09%；β-乳球蛋白在20～900 mg/L质量浓度范围内线性良好，相关系数为0.999 96；当牛乳中β-乳球蛋白加标量为600～4 727 mg/L，加标回收率为96.1%～103.0%、RSD为0.00%～2.23%。该方法分离效果好、重复性好，适用于巴氏杀菌乳中α-乳白蛋白和β-乳球蛋白的准确定量。

关键词: 巴氏杀菌乳；高效液相色谱法；α-乳白蛋白；β-乳球蛋白