Electrochemical thermospray mass spectrometry (ETMS) is a suitable method for the investigation of electrode precesses. The mechanism of the anodic oxidation of N,N-dialkylanilines in neutral aqueous solution and of phenothiazine in organic electrolyte solution have already been clarified by ETMS. By modification of the experimental setup, it is now possible to examine acidic electrolytes. The anodic oxidation of aniline, leading to the conducting polymer polyaniline and the anodic oxidation of N-alkylanilines were chosen for testing the new method. Thermospray mass spectra for aniline and N-alkylanilines as well as electrochemically generated products are shown. The potential dependent formation of dimeric and trimeric products and their structures are presented. A mechanism for the oxidation process is proposed.