A comprehensive analytical approach must be adopted in identifying and measuring the large variety of chemical substances that could impair driving. This paper presents an analytical methodology for screening and confirming the presence of psychoactive substances in both blood and urine samples. The methodology is recommended on the basis of years of epidemiological monitoring by the Centre of Behavioural and Forensic Technology at the University of Padova, Italy. Analytical techniques used include: (1) head space gas chromatography; (2) flame ionisation; (3) mass spectrometry; (4) immunoassay tests, including EMIT (enzyme multiplied immunoassay technique); (5) GC-MS (gas chromatography, mass spectrometry). A wide variety of drugs and psychoactive chemicals can be detected. The single-column extraction procedure used allows more than 90% of all these substances to be extracted, and there is good reproducibility of such recoveries with different batches of columns. Detection limits of 20 to 250 ng/mL are obtainable in blood, and of 10 to 150 ng/mL in urine. The main advantages of this analytical approach are: (1) only small volumes of biological fluids needed; (2) fewer procedures and analytical techniques used; (3) analyses take only 40min per sample; (4) relatively low cost.
Abstract