Quantitation and identification of ethanol and inhalant compounds in whole blood using static headspace gas chromatography vacuum ultraviolet spectroscopy

Abstract

Gas chromatography (GC) and vacuum ultraviolet spectroscopy (VUV) are powerful and complementary techniques for the analysis of small molecules in forensics. Most notably, flame ionization detection (FID) is commonly used with GC to identify and quantify volatile compounds. An FID's price point and ease of use makes it an attractive approach for routine laboratories that are in high demand for forensics analysis, but with the contingency that an FID relies on retention time for identification and quantification. A new and innovative method using static headspace gas chromatography coupled with vacuum ultraviolet (VUV) spectroscopy was developed for the quantitative determination of ethanol in blood and identification of inhalants. This study investigates the possibility of using VUV as an alternative technique to traditional methods that use FID and mass spectrometry (MS) in toxicology and forensic analysis. VUV brings both identification and quantitation based on Beer-Lambert's Law while using a simple single-column solution. This paper investigates 25 compounds, including ethanol, methanol, acetone, benzene, and toluene using a 130–240 nm wavelength range for identification and quantification using GC-VUV, even when coelutions occur. Ethanol was examined under a concentration range of 9 to 495 mg/dl, and the method was found to be linear with an r2 = 0.997 and a LOD of 3.1 mg/dl. Ethanol was fully separated from other volatile organic compounds (VOCs) as well as endogenous materials present in blood. Nonaromatic VOCs were analyzed at concentration ranges of 2.4 to 99 mg/dl with LODs around 0.2 mg/dl; aromatic VOCs were analyzed from 0.5 to 24 mg/dl with LODs ∼ 0.1 mg/dl.