Ou Yu-Meng, Kuo Shu-Yun, Lee Hsun, Chang Huan-Tsung, Wang Yi-Sheng
Genomic Research Center, Academia Sinica; Department of Chemistry, National Taiwan University.
Genomic Research Center, Academia Sinica.
J Vis Exp. 2018 Jul 29(137):57660. doi: 10.3791/57660.
Sample preparation is a critical process in mass spectrometry (MS) analysis of carbohydrates. Although matrix-assisted laser desorption/ionization (MALDI) MS is the method of choice in carbohydrate analysis, poor ion signal and data reproducibility of carbohydrate samples continue to be severe problems. For quantitative analysis of carbohydrates, an effective analytical protocol providing superior data quality is necessary. This video demonstrates sample preparation protocols to improve signal intensity and minimize data variation of carbohydrates in MALDI-MS. After drying and crystallization of sample droplets, the crystal morphology is reformed by methanol before mass spectrometric analysis. The enhancement in carbohydrate signal is examined with MALDI imaging mass spectrometry (IMS). Experimental results show that crystal reformation adjusts crystalline structures and redistributes carbohydrate analytes. In comparison with the dried droplet preparation method in conventional MALDI-MS, reforming carbohydrate crystal morphologies with methanol shows significantly better signal intensity, ion image distribution, and data stability. Since the protocols demonstrated herein do not involve changes in sample composition, they are generally applicable to various carbohydrates and matrixes.
样品制备是碳水化合物质谱（MS）分析中的关键过程。尽管基质辅助激光解吸/电离（MALDI）MS是碳水化合物分析的首选方法，但碳水化合物样品的离子信号差和数据重现性仍然是严重问题。对于碳水化合物的定量分析，需要一种能提供卓越数据质量的有效分析方案。本视频展示了用于提高MALDI-MS中碳水化合物信号强度并最小化数据变化的样品制备方案。在样品液滴干燥和结晶后，在质谱分析前用甲醇重塑晶体形态。用MALDI成像质谱（IMS）检查碳水化合物信号的增强情况。实验结果表明，晶体重塑可调整晶体结构并重新分布碳水化合物分析物。与传统MALDI-MS中的干燥液滴制备方法相比，用甲醇重塑碳水化合物晶体形态显示出明显更好的信号强度、离子图像分布和数据稳定性。由于本文展示的方案不涉及样品组成的变化，它们通常适用于各种碳水化合物和基质。
