Harvey D J
Oxford Glycobiology Institute, Department of Biochemistry, UK.
J Chromatogr A. 1996 Jan 12;720(1-2):429-46. doi: 10.1016/0021-9673(95)00307-x.
The technique of matrix-assisted laser desorption/ionization mass spectrometry (MALDI) is described and examples are given of its use for the examination of glycoproteins, glycopeptides, glycolipids and oligosaccharides. Abundant [M+H]+ ions are produced by the glycoproteins and glycopeptides, whereas glycolipids and oligosaccharides give mainly [M+Na]+ ions. Resolution on time-of-flight (TOF) instruments is poor but improved resolution can be obtained by use of ion cyclotron resonance or magnetic sector instruments. Although the technique gives mainly [M+Na]+ ions from neutral, underivatised oligosaccharides, with little fragmentation when implemented on TOF systems, the use of a reflectron enables fragment ions produced by post-source decay to be obtained. Acidic sugars give less satisfactory positive ion spectra with TOF analysers, but generally produce abundant negative ions. Extensive fragmentation is observed with these compounds when the spectra are recorded with magnetic sector instruments. Neutral glycolipids produce strong spectra from several matrices but acidic glycolipids show extensive fragmentation as the result of sialic acid loss.
本文描述了基质辅助激光解吸/电离质谱（MALDI）技术，并给出了其用于检测糖蛋白、糖肽、糖脂和寡糖的示例。糖蛋白和糖肽产生大量的[M+H]+离子，而糖脂和寡糖主要产生[M+Na]+离子。飞行时间（TOF）仪器的分辨率较差，但使用离子回旋共振或磁扇形仪器可提高分辨率。尽管该技术在TOF系统上对中性、未衍生化的寡糖主要产生[M+Na]+离子，且几乎没有碎片，但使用反射器可获得源后衰变产生的碎片离子。酸性糖在TOF分析仪上给出的正离子谱不太理想，但通常会产生大量负离子。当用磁扇形仪器记录光谱时，这些化合物会出现广泛的碎片。中性糖脂从几种基质中产生强光谱，但酸性糖脂由于唾液酸的损失而显示出广泛的碎片。
