Laboratory of Food Chemistry, Wageningen University, Bornse Weilanden 9, 6708, WG Wageningen, The Netherlands.
J Am Soc Mass Spectrom. 2024 May 1;35(5):1012-1020. doi: 10.1021/jasms.4c00029. Epub 2024 Apr 18.
To understand the mode of action of bioactive oligosaccharides, such as prebiotics, in-depth knowledge about all structural features, including monosaccharide composition, linkage type, and anomeric configuration, is necessary. Current analytical techniques provide limited information about structural features within complex mixtures unless preceded by extensive purification. In this study, we propose an approach employing cyclic ion mobility spectrometry (cIMS) for the in-depth characterization of oligosaccharides, here demonstrated for disaccharides. We were able to separate galactose and glucose anomers by exploiting the high ion mobility resolution of cIMS. Using the obtained monosaccharide mobilograms as references, we determined the composition and anomeric configuration of 4β-galactobiose by studying the monosaccharide fragments generated by collision-induced dissociation (CID) before the ion mobility separation. Drift times and individual MS spectra of partially resolved reducing-end anomers of 4β-galactobiose, 4β-galactosylglucose (lactose), and 4β-glucosylglucose (cellobiose) were obtained by deconvolution using CID fragmentation induced in the transfer region between the cIMS cell and TOF analyzer. The composition and anomeric configuration of the reducing end anomers of these disaccharides were identified using cIMS approaches, where first each anomer was isolated using cIMS and individually fragmented, and the monosaccharide fragments were again separated by cIMS for comparison with monosaccharide standards. With these results we demonstrate the promising application of cIMS for the structural characterization of isomeric oligosaccharides.
为了了解生物活性低聚糖（如益生元）的作用模式，需要深入了解所有结构特征，包括单糖组成、键合类型和端基构型。当前的分析技术在复杂混合物中提供的结构特征信息有限，除非事先进行广泛的纯化。在这项研究中，我们提出了一种使用循环离子淌度谱（cIMS）对低聚糖进行深入表征的方法，这里以二糖为例进行了演示。我们能够通过利用 cIMS 的高离子淌度分辨率来分离半乳糖和葡萄糖端基异构体。利用获得的单糖淌度图作为参考，通过研究离子淌度分离前碰撞诱导解离（CID）产生的单糖片段，确定了 4β-半乳糖二糖的组成和端基构型。通过使用 CID 碎裂在 cIMS 单元和 TOF 分析器之间的传输区域中诱导，获得了部分解析的 4β-半乳糖二糖、4β-半乳糖基葡萄糖（乳糖）和 4β-葡萄糖基葡萄糖（纤维二糖）的还原端端基异构体的淌度时间和单个 MS 谱。使用 cIMS 方法鉴定了这些二糖的还原端端基异构体的组成和端基构型，其中首先使用 cIMS 分离每个异构体并进行单独碎裂，并再次通过 cIMS 分离单糖片段以与单糖标准品进行比较。通过这些结果，我们证明了 cIMS 在异构低聚糖结构表征方面的应用前景。
