离子色谱法测定乳粉中低聚半乳糖含量

Determination of Galactooligosaccharides in Milk Powder by Ion Chromatography

建立离子色谱法定量测定乳粉中低聚半乳糖含量的方法。采用高效Carbo Pac PA20阴离子交换色谱柱和脉冲安培检测器检测、氢氧化钠和醋酸钠淋洗液梯度洗脱,并对淋洗液比例进行优化。优化后的方法低聚半乳糖线性范围为50~250 mg/L,其质量浓度与峰面积线性关系良好,相关系数R2=0.999 9,检出限为0.050 g/100 g。在3个浓度水平进行加标(5,10和20 g/L),加标回收率为98.9%~100.2%,相对标准偏差(RSD,n=6)范围为1.10%~2.47%。该方法具有简便、高效和准确的特点。

An analytical method was established to determine galactooligosaccharides（GOS） in milk powder by ion exchange chromatography.GOS was separated under gradient elution mode.Carbo Pac PA20 anion exchange column and pulsed amperometric detector were used to determine the contents of GOS.The mobile phase was sodium hydroxide and sodium acetate solution,and the proportion of eluent was optimized.The method presented linear correlation coefficient,and R2 was 0.999 9 when the concentration of GOS was in the range of 50-250 mg/L.The detection limit was 0.050 g/100 g.In 3 different degrees（5,10 and 20 mg/mL）,the recoveries were 98.9%-100.2%,and the relative standard deviation（RSD,n=6） ranged from 1.10% to 2.47%.The method was simple,efficient and high accuracy.