High-sensitivity detection and postsource decay of 2-aminopyridine-derivatized oligosaccharides with matrix-assisted laser desorption/ionization mass spectrometry.
The sensitivities of oligosaccharide derivatives in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) were compared using two matrixes, 2,5-dihydroxybenzoic acid (DHBA) and alpha-cyano-4-hydroxycinnamic acid (CHCA). For this purpose, maltopentaose was tagged with 2-aminopyridine (PA), 4-aminobenzoic acid ethyl ester (ABEE), and trimethyl-(p-aminophenyl)ammonium chloride (TMAPA). DHBA was more advantageous for enhancement than CHCA. Among the derivatives, the sensitivity with the PA-tagged maltopentaose showed a 100-fold improvement over the native one with DHBA as a matrix, while the oligesaccharide derivatized with ABEE and TMAPA gave 30- and 10-fold increases in sensitivity over the underivatized one. To obtain structural information from these derivatized oligosaccharides, postsource decay (PSD) during flight in the field-free drift in MALDI-TOFMS was measured. Predictable and reproducible fragmentation patterns could be obtained in all cases. Furthermore, we found matrix-dependence fragmentation with the PA-labeled oligosaccharide. With CHCA, a simple spectrum ascribable to Y series ions was obtained. On the other hand, both B and Y series ions were clearly observed in the DHBA case. The results demonstrate the usefulness of derivatives for sensitive analysis of oligosaccharides with MALDI.
Okamoto
M
M
Environmental Health Science Laboratory, Sumitomo Chemical Company, Ltd., Osaka, Japan.
Takahashi
K
K
Doi
T
T
Takimoto
Y
Y
D000631:Aminopyridines / Q000737:chemistry*; D002240:Carbohydrate Sequence; D003373:Coumaric Acids / Q000737:chemistry; D005841:Gentisates; D062385:Hydroxybenzoates / Q000737:chemistry; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000032:analysis* / Q000737:chemistry; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
D000631:Aminopyridines; D003373:Coumaric Acids; D005841:Gentisates; D062385:Hydroxybenzoates; D009844:Oligosaccharides; C007175:alpha-cyano-4-hydroxycinnamate; C019193:maltopentaose; C010925:2,5-dihydroxybenzoic acid; C032439:alpha-aminopyridine