Genomics Research Center, Academia Sinica, Taipei 115, Taiwan, ROC.
Genomics Research Center, Academia Sinica, Taipei 115, Taiwan, ROC; Chemistry Department, National Taiwan University, Taipei 106, Taiwan, ROC.
Anal Chim Acta. 2017 Nov 22;994:49-55. doi: 10.1016/j.aca.2017.09.024. Epub 2017 Sep 27.
Carbohydrate analysis is challenging due to lack of sensitive detection and efficient separation methods. Although matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) is a sensitive tool, the low ionization efficiency of carbohydrates makes mass analyses inefficient. This work systematically examines the correlation between MALDI-MS sensitivity and carbohydrate sample morphology. Depending on the properties of the matrix used, the morphology changes through sample recrystallization after drying or imposition of hydrodynamic flows during droplet drying. Observation shows that amorphous solids and finer crystals offer higher carbohydrate sensitivity and spatial homogeneity than larger crystals. Clear evidences of an inverse correlation between sensitivity and crystal size are obtained when various kinds of carbohydrates are mixed with different matrixes. Similar experiments on proteins and peptides showed a negative or negligible effect. The result serves as a general guideline for improving efficiency in routine carbohydrate analysis.
碳水化合物分析具有挑战性，因为缺乏敏感的检测和有效的分离方法。尽管基质辅助激光解吸/电离（MALDI）质谱（MS）是一种灵敏的工具，但碳水化合物的低离子化效率使得质谱分析效率低下。这项工作系统地研究了 MALDI-MS 灵敏度与碳水化合物样品形态之间的相关性。根据所用基质的性质，形态通过干燥后样品再结晶或液滴干燥过程中强制产生的流体动力学流而变化。观察表明，无定形固体和更细的晶体比大晶体提供更高的碳水化合物灵敏度和空间均匀性。当各种碳水化合物与不同基质混合时，获得了灵敏度与晶体尺寸之间存在反比关系的明确证据。对蛋白质和肽进行的类似实验显示出负面或可忽略的影响。该结果为提高常规碳水化合物分析效率提供了一般性指导。
