జర్నల్ ఆఫ్ ఎనలిటికల్ & బయోఅనలిటికల్ టెక్నిక్స్

నైరూప్య

Adjustment of Matrix-Assisted Laser Desorption/Ionization for Glycolipids

Yusuke Suzuki, Akira Okamoto, Anila Mathew and Yasunori Kushi

Gangliosides isolated from biological sources are usually detected as sodium/potassium adduct ions and these ions are easily fragmented by dissociation of labile glycosidic bonds in the positive ion mode Mass Spectrometry (MS). A large number of conditions for fragment suppression of these acidic glycolipids by using non-acidic matrices or changing metal additions have been demonstrated. Compared to sodium/potassium adduct ions, the cesium adduct ions suppress the fragmentation of these acidic glycolipids. On the contrary, lithium adduct ions induce the fragmentation, but generate more informative fragment ions of glycolipids than other alkali metal adduct ions in post-source decay, MS/MS as well as MS spectra. To suppress the fragmentation of labile glycosidic bond and generate more informative fragmentation, we have examined and established the optimal condition for the detection of [M+Li]+ of gangliosides (GM3 and GM2) using the matrix-assisted laser desorption/ionization time-of-flight MS by adjusting matrix and alkali metal salt combinations and concentrations.