Enhanced measurement of CsI cluster ions for mass calibration in MALDI-MS using sugar alcohols

摘要

A simple method for measuring CsI cluster ions ((CsI)nCs+ and (CsI)nIa?’) from CsI3 for mass calibration was developed using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The application of CsI3 with an additive, sugar alcohol (e.g., glycerol) or saccharide (e.g., dihydroxyacetone), on the MALDI plate resulted in an adequate series of CsI cluster ions within a mass range extending to over m/z 10000 in the linear mode. The additives may be involved in improving the distribution of CsI3 on the MALDI plate, thus aiding the effective measurement of cluster ions. Because of their ease in handling, CsI3 and sugar alcohol or saccharide solutions comprised a suitable general-purpose mass calibrant for MALDI-MS instruments.