Abstract

Background. Determining whether a positive blood alcohol concentration (BAC) originates from antemortem consumption or postmortem formation is a frequent issue in forensic toxicology, especially when markers of alcohol ingestion cannot be analyzed. This study presents a validated HS-GC-FID method for detecting and quantifying volatile compounds in human blood to assess the risk of postmortem ethanol formation in cadaveric samples.

Methods. The validation of the method was carried out in accordance with the Guidelines of the Scientific Working Group for Forensic Toxicology (SWGTOX, 2013). A Clarus 580 gas chromatographic system equipped with a Headspace Perkin Elmer Turbomatrix 16 and Rtx-BAC Plus 1 column (30 m, 0.32 mm ID, 1.8 μm df) were used for method development and method validation, the acquisition software was TotalChrom Navigator version 6.3. Isopropanol was used as internal standard. For method validation, blood’s healthy volunteers’ samples collected in vivo were obtained from the blood transfusion center of the University Hospital of Oran. Seven cadaveric samples, received in order to carry out postmortem toxicological investigations, were analyzed by the validated method.

Results. A group of six volatile substances (acetone, butanol, ethanol, isobutanol, methanol and propanol) well correlated with putrefaction and microbial activity, were qualitatively and quantitatively analyzed by a selective method validated by HS-GC-FID in biological samples. All volatile solvents were studied in the range up to 4000 mg/L in terms of selectivity/specificity, limit of detection (LOD) and limit of quantification (LOQ), linearity, precision, accuracy and bias. The LOD was 1 mg/L for all solvents with a LOQ between 50 mg/L and 100 mg/L. Bias, repeatability, reproducibility and accuracy studies have shown good results. The developed method was applied to real cases to estimate the relevance of the method.

Conclusions. The present method is suitable for the identification and quantification of volatile compounds and can be a reliable tool in forensic toxicology. However, further studies should be carried out to establish the modelling of the relationship between the ethanol produced and the concentration of volatile solvents produced.