Combination Strategy of Reactive and Catalytic Matrices for Qualitative and Quantitative Profiling of -Glycans in MALDI-MS.

Qualitative and quantitative analysis of -glycans by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is hampered mainly by the low ionization efficiency of analytes and their poor cocrystallization with traditional organic acid matrices. In the present study, a ombination trategy of eactive and atalytic atrices (CSRCM) was proposed for the on-target derivatization and detection of reducing -glycans: a novel reactive matrix, , 2,5-dihydroxybenzohydrazide (DHBH), having a skeleton structure similar to that of DHB, was designed and synthesized, and this reactive matrix was mixed with catalytic matrix DHB to form a rationally combinatorial matrix (DHB/DHBH). Qualitatively, DHB/DHBH could improve the ionization efficiency of reducing carbohydrates significantly. Quantitatively, the acid-base chemistry of DHB/DHBH leads to a uniform cocrystallization of analytes-matrix mixtures. Consequently, CSRCM provides accurate quantitation for -glycans with high derivatization efficiency and good linearity ( > 0.99) within 2 orders of magnitude on the basis of an internal standard method. Furthermore, the CSRCM was successfully applied to evaluating -glycan in serum samples of colorectal cancer patients, thus showing potential in clinical applications for biomarker discovery.