Detection and identification of phenazone-type drugs and their microbial metabolites in ground and drinking water applying solid-phase extraction and gas chromatography with mass spectrometric detection

A new analytical method applying in situ derivatization was developed to enable the extraction of polar drug metabolites from water samples by solid-phase extraction (SPE). An additional derivatization by silylation was used to enhance the sensitivity of analyte detection by gas chromatography–mass spectrometry (GC–MS). Thus, the two metabolites 1,5-di-methyl-1,2-dehydro-3-pyrazolone (DP) and 4-(2-methylethyl)-1,5-dimethyl-1,2-dehydro-3-pyrazolone (PDP), postulated for the degradation of phenazone and propyphenazone, were identified and detected up to the μg/L level in raw and drinking water samples from public water supply.