Urine Mescaline Screening With a Biochip Array Immunoassay and Quantification by Gas Chromatography-Mass Spectrometry.
Mescaline, the primary psychoactive chemical in peyote cactus, has been consumed for thousands of years in ancient religious ceremonies. The US military wanted to determine if mescaline intake was a problem for personnel readiness. Twenty thousand seventeen urine specimens negative for cannabinoids, cocaine, opiates, and amphetamines were tested for mescaline with the Randox Drugs of Abuse V (DOA-V) biochip array immunoassay at the manufacturers recommended cutoff of 6 mcgL. A sensitive and specific method for mescaline quantification in urine was developed and fully validated. Extracted analytes were derivatized with pentafluoropropionic anhydride and pentafluoropropanol and quantified by gas chromatography-mass spectrometry (GCMS) with electron impact ionization. Standard curves, using linear least squares regression with 1x weighting, were linear from 1 to 250 mcgL with coefficients of determination >0.994. Intra- and inter-assay imprecision was <4.4 coefficient of variation (%CV), with accuracies >90.4%. Mean extraction efficiencies were >92.0% across the linear range. This fully validated method was applied for the confirmation of urinary mescaline in 526 presumptive-positive specimens and 198 randomly selected presumptive-negative specimens at the manufacturers 6 mcgL cutoff. No specimen confirmed positive at the GCMS limit of quantification of 1 mcgL. Results indicated that during this time frame, there was insufficient mescaline drug use in the military to warrant routine screening in the drug testing program. However, mescaline stability, although assessed, could have contributed to lower prevalence. We also present a validated GCMS method for mescaline quantification in urine for reliable confirmation of suspected mescaline intake.