基于亲水相互作用色谱-串联离子阱质谱法分析的低聚半乳糖异构体糖苷键的初步鉴定

Preliminary analysis of glycosidic bond of galactooligosaccharide isomers by hydrophilic interaction liquid chromatography-tandem ion trap mass spectrometry

目的采用亲水相互作用色谱-串联离子阱质谱法分析鉴定低聚半乳糖及其氨基柱分离制备的级分中二糖和三糖异构体组成及其糖苷键特征。方法将二糖和三糖的各个异构体色谱峰的MS^2与MS^3的中性丢失离子特征及相对丰度与文献中相关数据比较,从而推测其异构体结构特征。结果初步定性了量子高科GOS产品中二糖及三糖异构体组成及糖苷键特征;并根据由Sugarpak1色谱柱分离和示差折光检测器检测得到的不同聚合度寡糖的相对百分比及各异构体峰高相对比例计得GOS产品中二糖和三糖的不同糖苷键异构体的相对含量。结论该方法简便、快速,可用于鉴别和表征不同来源的低聚半乳糖产品,有望进一步研究以解決目前乳品饮料等复杂的食品基质中GOS定性定量分析的难题。

Objective To identify glycosidic bond characteristic of disaccharide and trisaccharide isomers in galactooligosaccharide(GOS) and isomer fractions isolated from the GOS by hydrophilic interaction liquid chromatography-tandem ion trap mass spectrometry (HILIC-MSn ). Methods Relative abundance for characteristic m/z of neutral loss ions from disaccharide and trisaccharide had been acquired by MS2 and MS3 analysis and compared with relevant data in the literature. Results The disaccharide and trisaccharide isomer composition and glycosidic bond characteristics of the quantum high-tech GOS products were preliminarily determined. The relative content of every disaccharide and trisaccharide isomer of GOS was calculated based on the relative percentage of different polymerization degree oligosaccharides measured by HPLC with differential refractive index detector and the relative proportion of each isomer peak height. Conclusion This method is simple and rapid, and can be used to identify and characterize GOS products from different sources, which is expected to solve the problem of qualitative and quantitative analysis of GOS in complex food substrates such as dairy beverages.