Paper-in-Tip Bipolar Electrospray Mass Spectrometry for Real-Time Chemical Reaction Monitoring

Angew Chem Int Ed Engl. 2024 May 8:e202318169. doi: 10.1002/anie.202318169. Online ahead of print.ABSTRACTCapturing short-lived intermediates at the molecular level is key to understanding the mechanism and dynamics of chemical reactions. Here, we have developed a paper-in-tip bipolar electrolytic electrospray mass spectrometry platform, in which a piece of triangular conductive paper incorporated into a plastic pipette tip serves not only as an electrospray emitter but also as a bipolar electrode (BPE), thus triggering both electrospray and electrolysis simultaneously upon application of a high voltage. The bipolar electrolysis induces a pair of redox reactions on both sides of BPE, enabling both electro-oxidation and electro-reduction processes regardless of the positive or negative ion mode, thus facilitating access to complementary structural information for mechanism elucidation. Our method enables real-time monitoring of transient intermediates (such as N,N-dimethylaniline radical cation, dopamine o-quinone (DAQ) and sulfenic acid with half-lives ranging from microseconds to minutes) and transient processes (such as DAQ cyclization with a rate constant of 0.15 s-1). This platform also provides key insights into electrocatalytic reactions such as Fe (III)-catalyzed dopamine oxidation to quinone species at physiological pH for neuromelanin formation.PMID:38717236 | DOI:10.1002/anie.202318169
Source: Angewandte Chemie - Category: Chemistry Authors: Source Type: research