Multi-target methodology for the screening of blood specimens in drug-facilitated sexual assault cases

The forensic investigation of drug-facilitated sexual assaults (DFSA) requires the toxicological examination of biological matrices to detect possible substances in victims. Whole blood is an important sample since it is the only one available for analysis in a considerable percentage of cases. A new screening methodology was developed for the detection of 96 compounds related to DFSA in blood. Sample treatment was based on a procedure combining protein precipitation and phospholipid removal before HPLC-MS/MS analysis. The new method operates in scheduled multiple reaction monitoring (sMRM) mode and uses the hybrid operating of the third quadrupole as an ion trap. The blood samples preparation was studied comparing four different protein precipitation treatments and two widely used extraction techniques as solid phase extraction and liquid-liquid extraction. The analytical performance of the screening method was evaluated in terms of selectivity and limits of detection. Finally, successful results were obtained applying the new method to the analysis of fifteen samples from real cases of the National Institute of Toxicology and Forensic Sciences.