ONLINE PROBE FOR FAST ELECTROCHEMISTRY ELECTROSPRAY MASS-SPECTROMETRY- INVESTIGATION OF POLYCYCLIC AROMATIC-HYDROCARBONS/

A newly invented probe accessory for fast electrochemistry/electrospra y mass spectrometry (EC/ESMS) is presented and evaluated. The device f eatures a low-volume, three-electrode electrochemical cell which has b een designed with a minimum distance between the working electrode and the ''Taylor cone'' inherent to the electrospray process. This config uration limits the time between electrochemical generation of ions and mass spectrometric analysis to an absolute minimum. A fused-silica la yer insulates the microcylinder working electrode from the sample solu tion until immediately prior to the electrospray region, postponing el ectrode processes until the last moment. The same fused-silica layer i nsulates the working electrode from the surrounding auxiliary electrod e, a stainless steel capillary that also serves as the electrospray ca pillary. The performance and capabilities of the novel electrochemistr y/electrospray mass spectrometry system have been evaluated using poly cyclic aromatic hydrocarbons (PAHs) as test analytes. In the positive ion EC/ESMS mode, oxidized forms (one-electron removal) of PAHs are pr oduced in high yield. The ability to analyze reaction products appeari ng subsequent to the initial oxidation is also demonstrated.