20 May

Infrared Spectroscopy and the Falsely High Breath Test (by DaytonDUI)

The Intoxilyzer 8000 operates using the scientific principle of infrared (IR) spectroscopy, which identifies molecules based on the way they absorb infrared (IR) light. More specifically, when molecules in a breath sample are exposed to IR light the way they vibrate changes due to the bending of the (C-O, O-H, C-H, C-C) bonds. Each type of bond absorbs light at a known wavelength, thus the amount of IR absorption identifies a substance as ethanol and how much ethanol is in the sample.

But here’s the rub… The machine can identify any compound containing a methyl group molecular structure as ethanol thereby giving a falsely high reading. Of the myriad of substances found in a human breath, 70% to 80% contain a methyl group molecular structure. The key is to make the machine as specific as possible for ethanol and only ethanol. You would think that this would mean that over time we have employed machines with better IR technology and more and more filters to limit mistakes and increase specificity. Unfortunately, the opposite is true.

The Intoxilyzer 8000 utilizes a type of IR technology that is different from its predecessor, the Intoxilyzer 5000 and its competitor the BAC DataMaster instrument. The Intoxilyzer 8000 uses a pulsing IR lamp to excite the sample molecules and a pyro-electric detector to detect results. Compared to the continuous flow of IR and a cooled lead selenide detector in the other machines the 8000’s technology is slower, less precise, less reliable and less sensitive. The 8000 has been shown to fail to detect mouth alcohol and other interfering substances. Instead of employing additional “filters” to limit the result to ethanol the Intoxilyzer 8000 uses fewer than its predecessor or its competitor. This means that potentially innocent people may face arrest, prosecution and possibly conviction.

If you are on a diet or a diabetic, you may be susceptible to a false BrAC reading. The National Highway Traffic Safety Administration (NHTSA) has found that people who are diabetics or dieters can have acetone levels that are hundreds, if not a thousand of times higher than people who are not diabetics or dieters. The key issue here is that acetone is one of the many substances that can be falsely detected as ethyl alcohol by the Intoxilyzer 8000. Other common environmental compounds may also affect a test. Those substances include: compounds found in cleaning fluids, celluloid, gasoline, paint removers, and in lacquers. Other common substances that can result in false BAC levels are alcohol, vomit, or blood in the person’s mouth.

Studies conducted in Tennessee and Vermont determined that the Intoxilyzer 8000 did not produce results which could satisfactorily be relied upon for the prosecution of DUI (OVI) offenses. The instrument was evaluated for accuracy, precision and performance. The task force given the responsibility to approve instruments for use in Tennessee found that the “CMI Intoxilyzer 8000 did not yield satisfactory results” to accurately determine BAC levels. The instrument has run into a significant number of problems in Florida, Arizona and Minnesota as well.

If you face the possibility of an OVI conviction, contact Charles M. Rowland II immediately at (937)318-1384 or 888-ROWLAND.