离子色谱法测定婴幼儿配方乳粉中的糖类

为建立操作简便、快速有效、同时分析婴幼儿配方乳粉中多种糖类的离子色谱分析方法，采用高效阴离子交换柱分离-脉冲安培检测法建立婴幼儿配方乳粉中葡萄糖、蔗糖、乳糖、低聚半乳糖三糖、蔗果三糖、低聚半乳糖五糖、蔗果四糖和蔗果五糖的分析方法。考察色谱柱、柱温、检测波形和淋洗液（NaOH、NaAc）浓度及流速对8 种糖分离效果的影响。结果表明：选用CarboPac PA20阴离子交换柱，包括分析柱（3 mm×150 mm）和保护柱（3 mm×30 mm），流速0.30 mL/min，柱温30 ℃，在选定的流动相梯度洗脱程序条件下实现高效分离；本方法对葡萄糖、蔗糖、乳糖、低聚半乳糖三糖、蔗果三糖、低聚半乳糖五糖、蔗果四糖和蔗果五糖的检出限为3.0～12.0 μg/L，精密度实验相对标准偏差小于3%，豆浆样品中8 种糖类的加标回收率为78.0%～96.8%，表明该方法可行。

Determination of Sugars in Infant Formula by Ion Chromatography

The purpose of this study is to establish a simple, rapid and effective method for the simultaneous analysis of various saccharides (glucose, sucrose, lactose, galactooligotrisaccharide, kestose, galactooligopentasaccharide, nystose and 1F-fructofuranosyl nystose) in infant formula by high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). The effect of chromatographic columns, column temperature, detector waveforms, eluent concentration and flow rate on the separation of the 8 saccharides was evaluated. The analysis was performed on a CarboPac PA20 analytical column (3 mm × 150 mm) coupled with a guard column (3 mm × 30 mm) at a 0.30 mL/min flow rate. Column temperature was set as 30 ℃. Efficient separation was achieved using gradient elution. Under the optimal conditions, the detection limit was 3.0–12.0 μg/L for all analytes. The precision, expressed as relative standard deviation (RSD), was less than 3%. The recoveries of the 8 saccharides in spiked soymilk were 78.0%–96.8%, indicating the feasibility of this method.