Ricerca di sostanze psicotrope in campioni urinari di poliassuntori: confronto di metodiche immunochimiche e di spettrometria di massa (I e II livello)

Detection of psychotropic substances in urine samples from poliabuser: comparison of immunochemical and mass spectrometry methods (I and II level). The abuse of synthetic drugs has considerably increased in recent years. The fallen back of the phenomenon suggested us to revise two immunochemical tests commonly used, comparing results with those obtained from surveyings in gascromatography (GC) mass spectrometry (MS). For this study 33 urine samples from polyabusers were draft and subsequently analyzed in screening procedure with the method hOmogeneous Method Enzymatic Complex (OMEC) and, for the class of amphetamines, also with the method Fluorescences Polarization Immuno Assay (FPIA). Samples for GC-MS analysis were prepared using two different analytical methods: AZOLIQ and TOXISPE. At amphetamines cut-off values (1000 ng/mL for screening and 500 ng/mL for confirmation) 2 samples resulted positives and 20 negatives. 10 samples were positives in GC-MS (using either the cut-off value, n = 6 cases, or the LOD at 5 ppb, n = 4 cases) but negatives in screening, while 1 sample was negative in GC-MS but positive in OMEC. The GC-MS analysis allowed us to obtain the whole spectrum of other classes of abuse drugs, including metabolites of great interest. In conclusion, it is necessary to know the limits of the tests used and adopt cut-off values appropriate to the analysis purposes, since the negative samples in the screening procedure are generally excluded from successive confirmations.