DEVELOPMENT AND VALIDATION OF A QUANTITATIVE HS-GC/FID METHOD FOR ALCOHOL ANALYSIS IN BIOLOGICAL SAMPLES: STABILITY ASSESMENT

Abstract

Determination of blood alcohol concentration is one of the most common analyses in forensic toxicology laboratory practice. With reference to this, the aim of the present work was to develop a method for quantitative analysis of ethyl alcohol in blood by head space gas chromatography, with n-propanol as an internal standard and at the same time ensuring good resolution of ethyl alcohol and acetone using one capillary column. Validation parameters comprising selectivity, specificity, linearity, accuracy and precision have indicated that the method could be applied in routine analysis of ethyl alcohol in post-mortem and ante-mortem blood samples as well as in other biological fluids, in line with the set criteria based on the revised international guidelines. In post-mortem samples there are many interfering substances due to various reasons (as a result of acidosis, produced in vitro on account of an improper storage of the samples or during the autolysis / putrefaction phase of the body). Because of this occurrence, within the validation procedure, more attention was imparted to the stability of the samples, including processed sample, freeze-thaw and long-term stability estimation. The results of the additional stability tests have shown that applying of preservative significantly improved the stability of the samples by inhibiting the in vitro ethyl alcohol production.