Correlation between BAC and abdominal muscle alcohol concentration: a promising parachute matrix in cases of severe injury.

Ethanol represents the most abused drug worldwide, and among the most frequently evidenced in toxicological analysis on drug-induced/related deaths. When a blood sample is not available in a death characterized by severe trauma an alternative matrix is needed for an estimation of impairment. Presented is the correlation of postmortem blood and rectus abdominis muscle ethanol concentration. Ethanol concentrations in both blood (BAC) and muscle were determined by head space gas chromatography/mass spectrometry. Twenty-nine forensic cases with positive BAC were selected for the correlation study. Circumstances and time since death were known in all selected cases. Muscle analyses evidenced a linearity of the analytical response within the range (0.03–0.9) mgethanol/gmuscle). Quantification of three QC samples (0.15–0.3 and 0.6 mgethanol/gmuscle) through aqueous calibrators was superimposable to matrix-based one. The method was validated, by assessing specificity, recovery from biological matrix (92.5%), sensitivity (LOD of 0.15 mgethanol/gmuscle, LLOQ 0.03 mgethanol/gmuscle), bias of quantitative analyses was between 3.5% and 6.1%. ANOVA F-test was used to determine within-run and between-run precision, both resulted minor than 20%. A linear correlation between BAC and ethanol muscle levels was obtained for selected post-mortem samples and correlation equation (y = 0,5837x + 0,0353; R² = 0,8661) was used for BAC estimation in three forensic cases for which blood was not available. Rectus abdominis muscle was demonstrated as a good candidate to estimate blood alcohol concentration and impairment at the time of fatality.