Ethylenediaminetetraacetic acid (EDTA) as an auxiliary tool in the electrospray ionization mass spectrometry analysis of native and derivatized beta-cyclodextrins, maltoses, and fructans contaminated with Ca and/or Mg.

The effect of Ca(2+) (and Mg(2+)) and the disodium salt of ethylenediaminetetraacetic acid (EDTA), a well known Ca(2+) (and Mg(2+)) chelating agent, on the volatilization/ionization of carbohydrates by using electrospray ionization mass spectrometry has been studied. Model compounds such as maltoses (maltose to maltoheptaose), beta-cyclodextrins (beta-cyclodextrin, methyl-beta-cyclodextrin, heptakis(2,6-di-O-methyl)-beta-cyclodextrin, heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin, and 2-hydroxypropyl-beta-cyclodextrin) and fructans (sucrose, 1-ketose, nystose, and 1F-fructofuranosylnystose) were used.

Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry analysis of oligosaccharides and oligosaccharide alditols obtained by hydrolysis of agaroses and carrageenans, two important types of red seaweed polysaccharides.

MALDI-TOF mass spectrometry analyses of several oligosaccharides (aldoses) and oligosaccharide alditols derived from agaroses, kappa- and iota-carrageenans using different matrices (2,5-dihydroxybenzoic acid, nor-harmane, ferulic acid, and the ionic liquid matrices 2,5-dihydroxybenzoic acid-n-butylamine and ferulic acid-n-butylamine) were conducted. These carbohydrates were selected as model compounds to study the MALDI prompt and post-source decay (PSD) fragmentation processes of both families of oligosaccharides. Sulfated alditols showed in the negative-ion mode the molecular ion as [M-Na](-) together with the species yielded by their prompt fragmentation (mainly desulfation) while the sulfated oligosaccharides (aldoses) showed mainly glycosidic prompt fragmentation (glycosidic C-cleavages and desulfation). Non-sulfated aldoses and alditols, which could only be analyzed in positive-ion mode ([M+Na](+)), did not suffer any prompt fragmentation. The former yielded cross-ring fragmentation in the PSD mode. Best results were obtained by using 2,5-dihydroxybenzoic acid and/or nor-harmane as matrices for all the compounds studied.