56 / 2019-12-11 11:24:55

On–plate hydrazone formation: a novel strategy for glycoanalysis with MALDI MS

Hydrazide; Hydrazine formation; On-plate derivatization; MALDI-ToF-MS

Hydrazone formation is a promising derivatization strategy for N-glycan analysis in mass spectrometry profiting from its salt-free reaction system and stable derivatives， however the application range of hydrazide compounds has been limited due to their relatively high reaction temperature, acidic reaction condition or long reaction time. This work presents a new designed self-charged hydrazide tag, 4-(hydrazinecarbonyl)-N,N,N-trimethylbenzenaminium (HTMBA), which could effectively enhance the sensitivity of glycan in MALDI-MS analysis (~19fold) and has unprecedented reactivity in reducing end labeling. With 50-times excess reagent, derivatization completed in less than 5min. As such, we further applied it to on-target derivatization strategy in which matrix, purified glycan and reagent were added on target of MALDI stainless plate in sequence, specimens were then directly analyzed after thoroughly dry in air, reproducible and reliable spectra were acquired. This strategy was optimized with maltoheptaose (DP7) and was further validated with RNase B and human serum to prove its capability on labeling different types of glycan, on horse serum derived sample analysis, the strategy was proved having the ability to maintain the O-acetylated sialic acid information during MALDI-MS measurements.