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DUI Blood & Urine Testing: Understanding Gas Chromatography

Dayton DUI Attorney Charles Rowland > DUI Law  > DUI Process  > DUI Blood & Urine Testing: Understanding Gas Chromatography

DUI Blood & Urine Testing: Understanding Gas Chromatography

Gass chromatographer - oven with capliary colu...

If you have been arrested for a DUI involving blood testing you may encounter a testing procedure known as Gas Chromatography.  Gas Chromatography is the most reliable method for alcohol testing in blood and urine and has become the accepted gold standard in forensic toxicology.  Gas chromatography specificity for ethanol (drinking alcohol) is very good and this method can also identify and quantify other organic or interfering substances such as methanol and isopropanol. The two commonly used techniques for analyzing the gases are “direct injection” and “headspace analysis.”  The devise works by utilizing a flow-through tube known as the column.  The different chemicals in the sample pass via a gas stream at different rates depending on their interaction with the column’s filling.  As the chemicals exit the end of the column they are detected and electronically identified.

The defense of a blood test case should involve the use of an expert witness who will assist in two major ways.  First, the expert will know what to ask for and assist the attorney in obtaining the laboratory notes, data, chromatograms, computer printouts, worksheet packets and other important documentation related to the analysis of the subject sample.  One the proper documents are obtained, the expert can assist in looking for potential issues in the testing and/or the testing protocol.  These may include any of the following:

  • Improper chain of custody
  • Prolonged time in transport
  • Improper storage
  • Analyst did not follow SOP
  • Lab SOP not in compliance with forensic standards
  • Contamination of laboratory solutions
  • Leaking sample tubes
  • Mislabeling
  • Calibration and sourcing issues

I have attempted in every way I can to keep myself up-to-date on all issues involving forensic testing, including gas chromatography.  This has included attending the National College for DUI Defense annual seminar on DUI Defense, earning Forensic Sobriety Assessment certification and attending seminars from some of the world’s leading experts.  I recommend that any attorney defending cases involving these issues contact Alfred E. Staubus, PharmD, PhD, as he is a nationally recognized expert and someone who comes across well teaching to a judge or jury.  The future of drunk driving defense will continue to involve understanding blood and urine testing whether it be for drugs of abuse, prescription drug abuse, marijuana cases or alcohol blood tests.

Dayton DUI attorney Charles M. Rowland II dedicates his practice to defending the accused drunk driver.  He has the credentials and the experience to win your case and has made himself the Miami Valley’s choice for DUI defense.  Contact Charles Rowland by phone at 937-318-1DUI (937-318-1384), 937-879-9542, or toll-free at 1-888-ROWLAND (888-769-5263).  For after-hours help contact our 24/7 DUI HOTLINE at 937-776-2671.  For information about Dayton DUI sent directly to your mobile device, text DaytonDUI (one word) to 50500.  Follow DaytonDUI on Twitter @DaytonDUI or Get Twitter updates via SMS by texting DaytonDUI to 40404. DaytonDUI is also available on Facebook, www.facebook.com/daytondui and on the DaytonDUI channel on YouTube.  You can also email Charles Rowland at: CharlesRowland@DaytonDUI.com or write to us at 2190 Gateway Dr., Fairborn, Ohio 45324.

Sources for this article:

  1. Forensic Alcohol Analysis – Gas Chromatography, Alfred E. Staubus lecturing at the 16th Annual Mastering Scientific Evidence in DWI/DUI Cases, April 16-18, 2009.
  2. http://teaching.shu.ac.uk/hwb/chemistry/tutorials/chrom/gaschrm.htm
  3. http://www.answers.com/topic/gas-liquid-chromatography
Charles Rowland


Charles M. Rowland II has been representing the accused drunk driver for over 20 years. Contact him at (937) 318-1384 if you find yourself facing a DUI (now called OVI) charge.

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