Reaction Acceleration in Microdroplets‐MS: Inlet Capillary and Solvent Composition Effects

Rationale

Microdroplets chemistry has attracted tremendous interest in recent years. We have previously reported that microdroplets-MS achieves reaction acceleration. Herein we systematically investigated the effect of capillary heating of mass spectrometry inlet and microdroplets solvent polarity on the conversion ratios of dehydration and phosphorylation reactions.

Methods

The micron-size droplets generated by high-speed gas encapsulated the compounds. The conversion ratios of dehydration and phosphorylation reactions were investigated at different capillary temperatures of mass spectrometry inlet between 30°C and 300°C. Subsequently, the effects of different microdroplets solvents polarity (acetonitrile, acetonitrile/water (v/v: 9:1) and water) on microdroplet reactions were investigated.

Results

The microdroplets could be used as reaction vessels for rapid dehydration and phosphorylation reactions. Microdroplets-MS is characterized by the completion of the reaction in microseconds The increase of capillary temperature increased the conversion ratio of dehydration reactions but little effect on phosphorylation reactions. The stability of compounds provides support for this phenomenon. In addition, the increase of the solvent polarity in microdroplets promoted the dehydration reaction, but inhibits the nucleophilic substitution reaction (phosphorylation reaction).

Conclusions

Microdroplets-MS achieved an acceleration of the reaction, which was related to capillary temperature, microdroplets solvents and the stability of reaction products. This finding suggested that the inlet capillary and solvent system should be taken into account in the study and interpretation of microdroplets-MS.