Prerequisite knowledge of the effects of adduct ions on matrix-assisted laser desorption/ionization time of flight mass spectrometry of condensed tannins

Three different condensed tannins were analyzed using matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOFMS) by selection of Cs+ and Na+ as the cationization reagents. When Na+ was employed as the cationization reagent, condensed tannins gave the quality MALDI-TOF spectra, accompanying with the possibility of overevaluation of the gallocatechin/epigallocatechin units because of the influence of remaining K+. It is critical to investigate the appearance of gallocatechin/epigallocatechin units in condensed tannins from specially plant tissues. Cs+ is a suitable substitute for this situation. The more complicated MALDI-TOF spectrum of the complex condensed tannins from Bruguiera gymnorrhiza leaves was detected by selection of Cs+ as the cationization reagent with the presence of Na+ and K+. Using MALDI-TOF with no deionization or deionization and selection of Cs+ as the cationization reagent rather than with denionization and selection of Na+, the condensed tannin polymers of higher polymerization degree (PD) was oberved. Meanwhile, the polymer with the highest intensity ion peak changed with different ion adducts.