Alcohol is not Always Ethanol

     Ethanol or ethyl alcohol contains two carbon atoms linked to hydrogen atoms (methyl groups) and one oxygen atom linked to a hydrogen atom (hydroxyl group).  Most infrared breath testing devices rely upon the absorption of light at the 3.39 and 3.48 micron wavelengths, which are characteristic of the carbon-hydrogen bond,  for the determination of breath alcohol concentration.   However, at these wavelengths the infrared energy will be absorbed by many organic molecules containing carbon atoms bonded to hydrogen atoms, including hexane, toluene, and methyl ethyl ketone. 

     Experiments have shown that the Intoxilyzer 5000 will report these substances as ethyl alcohol and will print what purports to be a breath alcohol concentration.  In other words, the results for substances other than ethyl alcohol are reported as alcohol.  The research leaves little doubt that the instrument simply cannot distinguish the different alcohols from each other.   The numerical results are always reported as grams of alcohol per 210 liters of breath even when there is no ethanol in the breath sample.  

     The results for these interfering substances once again demonstrate the non-specificity of the Intoxilyzer 5000 and any other breath analyzer that relies on the the absorption of energy by the carbon-hydrogen bond in the 3.39 and 3.48 micron range.   

Written by Allen Trapp who is board certified by the National College for DUI Defense and the author of Georgia DUI Survival Guide Visit Website Written by Allen Trapp who is board certified by the National College for DUI Defense and the author of Georgia DUI Survival Guide Visit Website

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One Response to “Alcohol is not Always Ethanol”

  1. Users of Ignition Interlock Devices should be aware that alcohol readings are not
    always caused by alcohol in the user’s bloodstream, this is only one of three possible causes. Alcohol readings can also be caused by a malfunction of the interlock device or the device mistaking another substance for ethyl alcohol in the user’s bloodstream. In my practice as a Massachusetts Interlock Device Defense Lawyer, I have personally seen common products such as hand sanitizer,
    power bars, chewing gum, windshield washer fluid, anti-freeze, baked goods, and flavored coffee all be mistaken by interlock devices as alcohol. Interlock users
    should be aware of the possibility of contamination by these and other sources. All interlock users should take steps to protect themselves from false positive interlock readings. These steps include documenting any unusual occurrences with the IID, immediately reporting false interlock device readings, and not ingesting anything except water before or during interlock usage. One of the best things you can do when you get a false positive reading is to immediately go to a police station or hospital to get a comparison blood alcohol test. Following these steps may prevent you from facing a license suspension as a result of an interlock violation.

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