Hair analysis by liquid chromatography-tandem mass spectrometry in toxicological investigation of drug-facilitated crimes: report of 128 cases over the period June 2003-May 2004 in metropolitan Paris.

In recent years, reports of drug-facilitated crimes (DFC) have been increasing. The drugs involved are sometimes difficult to detect, because of their low dosages and the long time ellapsed between alleged DFC and blood and urine sampling. In order to detect benzodiazepines and benzodiazepine-like hypnotics, we developed an approach for hair analysis by liquid chromatography-tandem mass spectrometry using a triple stage quadrupole with an electrospray ionization (LC-ESI-MS/MS). Separation was performed on an Uptisphere ODB C18 column using a gradient of 2mM formate buffer and acetonitrile. For the 23 compounds studied, detection limits are lower than 2 pg/mg, but a specific extraction procedure is needed for 7-amino metabolites. Over a 1-year period within the city limits of Paris and three suburbs, we tested blood and urine from victims of sexual assaults, robbery and battery in which psychoactive substances were suspected of being involved. Hair was collected 4-8 weeks after the alleged DFC. Over the 128 cases studied, results of simultaneous analysis of blood, urine, and hair allowed us to conclude that 23 cases were real DFC. In 18 cases, no conclusion was possible since no hair was sampled and/or results were negative. In 56 cases, victims were previously using narcotics, cannabis, and/or a prescribed drug, according to the compounds detected in hair strands. Thirty-one cases were not DFC cases. This study indicates that the prevalence of zolpidem and clonazepam is high, followed by bromazepam, nordazepam, and midazolam. Others benzodiazepines and analogs are rare. LC-ESI-MS/MS is a good tool for toxicological investigations of DFC. Testing blood, urine, and hair by this technique may reveal drug presence, even if it was administered at a single therapeutic dose. That may be helpful to prosecute perpretators or to exclude a drug-facilitated crime.