MALDI‐MS Analysis of Sucrose Using a Charcoal Matrix with Different Cationization Agents

Abstract

We used matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) to analyze sucrose with a charcoal matrix and different cationization agents: Li+, Na+, K+, Rb+, Ag+, and Cs+. We observed a higher cation‐adducted sucrose peak with significantly reduced interference when analyzing sucrose with a charcoal matrix rather than 2,5‐dihydroxybenzoic acid (DHB) or α‐cyano‐4‐hydroxycinnamic acid (CHCA). However, the charcoal matrix caused glycosidic bond cleavage, resulting in sucrose fragment peaks. These could not be removed, even when we reduced the laser intensity. The degree of sucrose fragmentation was inversely related to the size of the cation additive. More sucrose fragmentation occurred when we used small cationization agents (Li+, Na+, or Ag+), while little fragmentation occurred when we used relatively large cationization agents (K+, Rb+, or Cs+). Charcoal has a higher energy transfer efficiency than DHB or CHCA as a matrix in MALDI‐MS. This may explain the increase in sucrose peaks and fragmented peaks observed when sucrose was analyzed with a charcoal matrix. The energy transfer efficiency was inversely proportional to the size of the cationization agent.