Qualitative screening analysis of urine samples by GC-MS method: Application in forensic toxicology

Abstract

Toxicological screening is used to identify the ingested toxic in order to confirm or to refute a possible cause of toxic death. A gas chromatography–mass spectrometric (GC-MS) method allows toxicological screening of drugs and pesticides when the toxic is unidentified. The purpose of this study is to describe the data and the results of the screening analyses in forensic toxicology carried out by GC-MS at the toxicology laboratory of Annaba University Hospital. Toxicological screening has been realized following the suspicion of a toxic death, in the context of chemical submission (CS) and for drivers involved in traffic accidents. Analyses were performed on urine samples by GC-MS (a GC-Perkin Elmer, Clarus® 680 coupled to a Perkin Elmer mass spectrometer, Clarus® SQ8T) after a liquid-liquid extraction using tetrazepam as internal standard. Between May 2018 and March 2019, sixteen cases were included. The average age of the cases was 31.62 ± 12.55 years. The sex ratio (M/F) was 07. The requests were mainly from the forensic medicine service of Annaba University Hospital (31.25%) followed by forensic medicine service of SOUK AHRAS, EL KALA and EL BESBES with a rate of 18.75% and last and in the same rank the forensic medicine service of Guelma and the police department with a rate of 6.25%. Among these sixteen cases, the number of positive cases was 14 (87.50%), represented mainly by tobacco markers, and at a rate of 71, 42% followed by drugs, caffeine and cocaine, with a rate of 25%, 23.81% and 4.76%, respectively. The toxicological screening confirmed and identified the presence of urinary drugs and different molecules belonging to various drug classes in a forensic toxicology context.