Structural characterization of hexoses and pentoses using lead cationization. An electrospray ionization and tandem mass spectrometric study

✍ Scribed by Jean-Yves Salpin; Jeanine Tortajada

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 182 KB
• Volume: 37
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/jms.289

✦ Synopsis

Abstract

The analytical potential of the complexation of isomeric underivatized hexoses (D‐glucose, D‐galactose, D‐mannose, D‐talose, D‐fructose), methylglycosides (1‐O‐methyl‐α‐D‐glucose and 1‐O‐methyl‐β‐D‐glucose) and pentoses (D‐ribose, D‐xylose, D‐arabinose and D‐lyxose) by Pb^2+^ ions, was investigated by electrospray ionization and tandem mass spectrometry (MS/MS). Pb^2+^ ions react mainly with monosaccharides by proton abstraction to generate [Pb(monosaccharide)~m~ − H]^+^ ions (m = 1–3). At low cone voltage, a less abundant series of doubly charged ions of general formula [Pb(monosaccharide)~n~]^2+^ is also observed. The maximum number n of monosaccharides surrounding a single Pb^2+^ ion depends on the metal : monosaccharide ratio. Our study shows that MS/MS experiments have to be performed to differentiate Pb^2+^‐coordinated monosaccharides. Upon collision, [Pb(monosaccharide) − H]^+^ species mainly dissociate according to cross‐ring cleavages, leading to the elimination of C~n~H~2__n__~O~n~ neutrals. The various fragmentation processes observed allow the C(1), C(2) and C(4) stereocenters of aldohexoses to be characterized, and also a clear distinction aldoses and fructose. Furthermore, careful analysis of tandem mass spectra also leads to successful aldopentose distinction. Lead cationization combined with MS/MS therefore appears particularly useful to identify underivatized monosaccharides. Copyright © 2002 John Wiley & Sons, Ltd.