Keywords: Blood Alcohol, Headspace Analysis
Forensic laboratories face the need to analyze many samples of human blood and body fluids for alcohol content. The large number of samples that require quantification of ethanol in these facilities creates a challenge for the methodology employed. Factors that need to be considered are sample throughput, resolution, and carryover. A successful method for these analyses should be fast, precise, and accurate. Current methods use a gas chromatograph coupled to a static headspace sampler and flame ionization detector (FID). The x, y, z robotic autosampler used in this study has a capacity of up to 128 headspace samples, which is a distinct advantage when compared to other commercially available samplers. Results obtained with the instrument and methodology described in this report meet the specifications set by the California Department of Justice Blood Alcohol Operating Procedures (Title 17). A dual-column, dual-FID blood alcohol analysis system that can be used for confirmation of ethanol peaks was also tested and produced results with good precision (below 5 % RSD).
Keywords: Ethanol; Robotic autosampler; Automation; Blood alcohol
Ethanol Analysis from Biological Samples by Dual Rail Robotic Autosampler*
Cynthia L. Morris-Kukoski, Eshwar Jagerdeo *∗, Jason E. Schaff, Marc A. LeBeau Federal Bureau of Investigation Laboratory, Quantico, VA, United States
Journal of Chromatography B, 850 (2007) 230–235
© 2007 Elsevier B.V. All rights reserved. Available online at www.sciencedirect.com
Detection, identification, and quantitation of ethanol and other low molecular weight volatile compounds in liquid matrices by headspace gas chromatography–flame ionization detection (HS–GC–FID) and headspace gas chromatography–mass spectrometry (HS–GC–MS) are becoming commonly used practices in forensic laboratories. Although it is one of the most frequently utilized procedures, sample preparation is usually done manually. Implementing the use of a dual-rail, programmable autosampler can minimize many of the manual steps in sample preparation. The autosampler is configured so that one rail is used for sample preparation and the other rail is used as a traditional autosampler for sample introduction into the gas chromatograph inlet. The sample preparation rail draws up and sequentially adds a saturated sodium chloride solution and internal standard (0.08%, w/v acetonitrile) to a headspace vial containing a biological sample, a calibrator, or a control. Then, the analytical rail moves the sample to the agitator for incubation, followed by sampling of the headspace for analysis. Using DB-624 capillary columns, the method was validated on a GC–FID and confirmed with a GC–MS. The analytes (ethanol, acetonitrile) and possible interferences (acetaldehyde, methanol, pentane, diethyl ether, acetone, isopropanol, methylene chloride, n-propanol, and isovaleraldehyde) were baseline resolved for both the GC–FID and GC–MS methods. This method demonstrated acceptable linearity from 0 to 1500 mg/dL. The lower limit of quantitation (LOQ) was determined to be 17 mg/dL and the limit of detection was 5 mg/dL.
*This is publication 06-14 of the Laboratory Division of the Federal Bureau of Investigation. Names of commercial manufacturers are provided for identification purposes only, and inclusion does not imply endorsement by the FBI.
** Corresponding author at: Federal Bureau of Investigation Laboratory, 2501 Investigation Parkway, Quantico, VA 22135, United States. Tel.: +1 703 912 6388. E-mail address: Eshwar.Jagerdeo@ic.fbi.gov (E. Jagerdeo).