Online investigation of reaction acceleration and reaction mechanism by thermospray ionization mass spectrometry

Abstract Thermospray ionization (TSI) technique was used for online monitoring of Borsche–Drechsel reaction, Diels-Alder reaction, and Combes reaction. The TSI was able to provide abundant thermal energy for the reactions solution and the droplets of reaction solution formed by thermospray online in very short time, therefore reaction acceleration effects in TSI condition could be observed, especially for the reaction with normally the need of high temperature in bulk-phase condition. Moreover, some short-lived intermediates could be captured by the TSI due to supersonic spray and the informative mass spectra were obtained to elucidate the reaction mechanism. In contrast to TSI, some reaction products were hard to obtain by electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) mass spectrometric analysis. Subsequently, the TSI was further improved by the introduction of a corona probe (i.e. corona-assisted TSI) to promote further reaction and enhance ionization efficiency. The TSI and corona-assisted TSI as flexible and versatile techniques may be potentially useful in reaction monitoring especially the reaction of high temperature.