"High-performance liquid chromatography-tandem mass spectrometry and supercritical fluid chromatography-tandem mass spectrometry enantioselective analysis of α-pyrrolidinopentiophenone and its phase-1 metabolites in biological samples"

With the aim to evaluate the potential of supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS) for forensic and clinical toxicology analyses, in this study the performance of high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and SFC-MS/MS for the enantioselective analysis of α-pyrrolidinopentiophenone (α-PVP), a drug of abuse, and its metabolites was evaluated. Accordingly, two independent separation methods were developed. The enantiomer elution order was determined using electronic circular dichroism (ECD) spectroscopy in combination with density functional theory (DFT) calculations. Developed HPLC-MS/MS and SFC-MS/MS methods were applied for the enantioselective analysis of α-PVP and several key phase-1 metabolites in human urine and oral fluid (OF) samples, enabling a preliminary study on α-PVP enantioselective metabolism in vivo . The stereochemical stability of α-PVP in OF, urine and HPLC mobile phase was investigated, showing that racemization of α-PVP in urine is significantly slower than in OF at room temperature. Regarding the biological samples, no enantioselective metabolism was observed, likely due to fast α-PVP racemization in these matrices. Metabolically unchanged α-PVP was also detected in all the urine and OF samples. Neither HPLC-MS/MS nor SFC-MS/MS methods described in this paper were optimized, because this investigation was performed with exploratory intentions to get general information focused on the suitability of enantioselective SFC-MS/MS for practical, real-life problem solving in clinical toxicology and forensic analysis.