Resonance-Enhanced Multiphoton Ionization/Time-of-Flight Mass Spectrometry for Sensitive Analysis of Product Ions Formed by Online Concentration from Analyte Adsorption/Laser Desorption

Resonance-enhanced multiphoton ionization/time-of-flight mass spectrometry (REMPI/TOFMS) was developed for the analysis of product ions formed by online concentration/laser desorption (Online COLD). In the online COLD system, which is one of the sample introduction techniques for REMPI/TOFMS, the analyte molecules are adsorbed at the tip of the capillary column and then are heated and vaporized by introducing a desorption laser. In the present study, the molecules concentrated at the tip reacted to the application of an intense desorption laser. The product species was dependent on the reactant, i.e., chlorodiphenyl ether was formed from p-chlorophenol while dibenzo-p-dioxin was formed from o-chlorophenol. In addition, the transient signal intensities of reactant and product ions were monitored, and the probable reaction processes were discussed. The present technique confers advantages such as high sensitivity/selectivity and rapidity, and therefore, this technique provides a novel method for monitoring the process of molecular reaction.