Monitoring organic reactions with on-line atmospheric pressure ionization mass spectrometry: the hydrolysis of isatin

Time-resolved electrospray ionization mass spectrometry (ESI-MS) is a power ful tool for interrogating solution-phase reaction systems. Both mechanisti c and kinetic information can be obtained using this technique. The title r eaction offers the opportunity to examine the effects of different ionizati on scenarios with regard to monitoring reactant consumption and product for mation. The hydrolysis of isatin was monitored in real time using a variety of ESI schemes: positive ion ([M + H](+), [M + Li](+), [M + Na](+)) and ne gative ion [M - H](-). The utility of each ionization approach, with respec t to the spectral features afforded for reaction tracking was examined. A c omparison of first-order hydrolysis kinetics data obtained using negative i on mass spectrometry is made with data acquired via an optical technique. C opyright (C) 2001 John Wiley & Sons, Ltd.