COMPARISON OF HIGH-ENERGY AND LOW-ENERGY COLLISION-INDUCED - DISSOCIATION TANDEM MASS-SPECTROMETRY IN THE ANALYSIS OF GLYCOALKALOIDS AND THEIR AGLYCONS

Four aglycons (tomatidine, demissidine, solanidine, and solasodine) an d three glycoalkaloids (alpha-tomatine, alpha-chaconine, and alpha-sol anine) have been analyzed by positive ion liquid sec ondary ion high-e nergy and low-energy collision-induced dissociation (CID) tandem mass spectrometry, performed on a four-sector (EBEB) and a hybrid (EBQQ) in strument, respectively. Both high- and low-energy collision-induced di ssociation mass spectra of [M + H](+) ions of these compounds provided structural information that aided the characterization of the differe nt aglycons and of the carbohydrate sequence and linkage sites in the glycoalkaloids. Low-energy CID favors charge-driven fragmentation of t he aglycon rings, whilst high-energy CID spectra are more complex and contain additional ions that appear to result from charge-remote fragm entations, multiple cleavages, or complex charge-driven rearrangements . With respect to the structural characterization of the carbohydrate part, low-energy CID fragmentations of sugar residues in the glycoalka loids generate Y-n(+) ions and some low intensity Z(n)(+) ions; the hi gh-energy spectra also exhibit strong (1,5)X(n)(+) ions, formed by mul tiple cleavage of the sugar ring, and significant Z(n)(+) ions.