Thermal desorption counter‐flow introduction atmospheric pressure chemical ionization for direct mass spectrometry of ecstasy tablets

A novel approach to the analysis of ecstasy tablets by direct mass spectrometry coupled with thermal desorption (TD) and counter‐flow introduction atmospheric pressure chemical ionization (CFI‐APCI) is described. Analytes were thermally desorbed with a metal block heater and introduced to a CFI‐APCI source with ambient air by a diaphragm pump. Water in the air was sufficient to act as the reactive reagent responsible for the generation of ions in the positive corona discharge. TD‐CFI‐APCI required neither a nebulizing gas nor solvent flow and the accompanying laborious optimizations. Ions generated were sent in the direction opposite to the air flow by an electric field and introduced into an ion trap mass spectrometer. The major ions corresponding to the protonated molecules (M + H]⁺) were observed with several fragment ions in full scan mass spectrometry (MS) mode. Collision‐induced dissociation of protonated molecules gave characteristic product‐ion mass spectra and provided identification of the analytes within 5 s. The method required neither sample pretreatment nor a chromatographic separation step. The effectiveness of the combination of TD and CFI‐APCI was demonstrated by application to the direct mass spectrometric analysis of ecstasy tablets and legal pharmaceutical products. Copyright © 2009 John Wiley & Sons, Ltd.