DOI
https://doi.org/10.25772/kf42-v152
Defense Date
2021
Document Type
Directed Research Project
First Advisor
Dr. Michelle R Peace
Second Advisor
Justin Poklis
Third Advisor
Dr. Marilyn Huestis
Fourth Advisor
Dr. Leslie Edinboro
Abstract
Ethanol is one of the most commonly encountered substances in toxicology analysis and is the most misused substance. Blood alcohol concentration (BAC) analysis is performed for a variety of scenarios, including cases of driving under the influence, drug facilitated crimes, intoxication deaths, workplace drug testing, substance use treatment centers, probation/parole, and other clinical settings. Due to the high prevalence of ethanol in forensic and clinical casework a fast, accurate, and cost effective method for BAC analysis is critical. Headspace gas chromatography with flame ionization detection (HS-GC-FID) is the standard for BAC analysis. This is due to its ease of use, automation, sensitivity, and accuracy, and with dual GC columns of differing polarity, confident compound identification with improved separation and enhanced specificity is achieved. Traditionally, headspace gas chromatography mass spectrometry (HS-GC/MS) is not employed as often for BAC analysis partly due to the expense, but more recent methods using the MS detector for BAC analysis are emerging. MS provides unequivocal identification that FID cannot provide by matching the mass spectrum to that of the corresponding standard spectrum. When interferences that coelute with ethanol are present, a lack of resolution when using FID results. The goal of this project is to evaluate the performance of the HS-GC dual FID configuration against the performance of the HS-GC-MS/FID configuration for analysis of ethanol, methanol, isopropanol, and acetone in blood. This study encompasses the method development and validation of the HS-GC dual FID configuration. The working range of the validated method, using a linear regression model, was 0.01-0.3 g/dL for all components. The limit of detection was 0.005 g/dL, and the lower limit of quantitation was 0.01 g/dL for all components. The bias for all QC samples (0.03, 0.18, and 0.32 g/dL) was within ± 8% of the target concentration for all components. The between-run and within-run precision for all QC samples was within ± 2.5% for all components. Following a high concentration sample of 0.4 g/dL, there was no analyte carryover for all components. There was a single ethanol interference on the TC-ALC 1 column, but not the TG-ALC Plus II column – allowing for the ethanol identification to not be confirmed. There were no other interferences from matrix or other commonly encountered volatile organic compounds. Forty clinical samples were tested with the validated method. One sample was positive for ethanol (0.18 g/dL), and three samples were positive for acetone (0.011, 0.023, and 0.047 g/dL).
Rights
© The Author(s)
Is Part Of
VCU Master of Science in Forensic Science Directed Research Projects
Date of Submission
5-4-2021