用毛细管电泳测定牦牛乳中的乳清酸含量

Detection of Orotic Acid in Yak Milk by Capillary Electrophoresis

建立了毛细管电泳(CE)测定乳中乳清酸含量的方法。用三氯乙酸提取昌台牦牛(Bos grunniens)和两种品牌液态乳脱脂乳中的乳清酸,然后用毛细管电泳进行分离和定量。对试验条件(缓冲液浓度、p H等)进行了优化,乳清酸色谱保留时间为15 min左右,最小检测限为0.02 mg/100 m L,在检测范围内线性关系良好(R2=0.999),回收率为99.66%。试验共测定了12头处于泌乳中期的昌台牦牛乳中的乳清酸含量,平均含量为(5.2±2.4)mg/100 m L,个体间含量差异较大。两种商业品牌的液态乳中乳清酸的含量平均为7.4 mg/100 m L,其中冷藏乳中乳清酸含量均高于常温乳,牦牛乳中的乳清酸含量低于商业液态乳。

This study has developed a method for analyzing orotic acid content in milk by capillary electrophoresis. Orotic acid was extracted by using trichloroacetic acid from the skim milk of Changtai yak（Bos grunniens） and liquid milk of two commercial brands, then separated and quantitatively analyzed by capillary electrophoresis. In this study, the experimental conditions（buffer concentration, p H, etc.） were optimized, the orotic acid retention time was about 15 min and the minimum detection limit was 0.02 mg / 100 m L, with good linear relationship（R2=0.999） and recovery rate（99.66%）. The average orotic acid content of 12 milk samples of Changtai yak at mid lactation was 5.2±2.4 mg /100 m L, which showed great differences among individuals. The average orotic acid content of two commercial brands of liquid milk was 7.4 mg / 100 m L. The content of orotic acid in refrigerated milk were higher than room temperature milk. In addition, the orotic acid content in yak milk was lower than in commercial liquid milk.