Use of The Intoxilyzer 5000 in North Carolina
If you have been charged with Driving While Impaired (DWI / DUI) in North Carolina, you likely were asked to provide a breath sample to be analyzed with an Intoxilyzer 5000. The Intoxilyzer 5000 is an infrared spectrophotometer used to analyze the concentration of alcohol (ethanol) in an individual's body. The results generated from this machine are admissible in North Carolina courts as evidence of intoxication during DWI trials.
The State’s case against you is dependant upon the reliability and admissibility of the evidence against you. When problems occur in the administration of an Intoxilyzer 5000 breath test, it can render the test as unreliable or inadmissible. Understanding how the Intoxilyzer 5000 operates is often a critical aspect of determining if there were problems in the administration of the test. Mr. Wesley Everett, of Everett Law Firm, P.A., earned a Bachelor of Science in Chemistry from the University of North Carolina in 1987 and is uniquely qualified to evaluate the scientific principles utilized in the administration of the Intoxilyzer 5000.
Although recent updates to the DWI law in North Carolina have attempted to limit challenges to Intoxilyzer 5000 results, the problems with the accuracy of the test remain. Even though a number of issues can cause problems with Intoxilyzer results, there are three primary issues based upon scientific principles that make the instrument unreliable. They are:
1) HENRY'S LAW
- RULE: When a volatile chemical, such as ethanol, is dissolved in a liquid, such as blood, and it is placed in a sealed container and at a constant temperature, the concentration in the liquid and gas, of the volatile chemical, will reach equilibrium.
- APPLICATION: By measuring the amount of ethanol in an air sample the Intoxilyzer 5000 attempts to calculate the amount of alcohol in the individual's blood.
- ISSUES: The pressure and temperature in an individual's lungs are constantly changing so the sample injected into the instrument cannot accurately provide data as to the alcohol concentration in blood. Moreover, the instrument must be air tight and be at a known constant temperature to provide an accurate reading of the injected sample. Variations in any of the above variables, will cause the sample to yield an erroneous reading.
2) BEER'S LAW
- RULE: The amount of light absorbed by a molecule (ethanol) is directly proportional to the concentration of the substance
- APPLICATION: By calibrating the Intoxilyzer machine with a known concentration of ethanol and measuring the infrared light that is absorbed by that standard, that when an unknown sample is introduced into the machine, the instrument can calculate the concentration of that sample.
- ISSUE: Assuming that the standard is correct, the sensors are working properly, there are no contaminants and the other variables remain constant, the calculations should work properly. Unfortunately, the Intoxilyzer 5000 machines are often many years old, not inspected with sufficient regularity and do not always generate accurate readings. Often isolating the problem is difficult for even the most experienced technician.
3) PARTITION RATIO
- RULE: In order to calculate the amount of alcohol in the blood based on the amount of alcohol in an air sample, an assumptive ratio has to be used in the calculation.
- APPLICATION: The "Partition Ratio" used in calculating the concentration of ethanol in the blood relative to the amount found in the air sample is 2100:1.
- ISSUE: The ratio of ethanol in an air sample versus the amount of ethanol in an individual's blood depends on numerous factors. An individuals body fat, their lung capacity, respiration rate, body temperature... can all affect the partition ratio of a given individual. Therefore, someone who has a Partition Ration of 1800:1 will be generate a reading that is higher than that individual's actual blood alcohol concentration.
It should also be noted that in certain circumstances, individuals convicted of drunk driving may be required to place an Ignition Interlock on their vehicles. The attorneys at Everett Law Firm, P. A. are knowledgeable with the technical aspects of the Intoxilyzer 5000 and the legal implications of the results generated by the equipment. Call today for a free initial consultation regarding your Driving While Impaired (DWI / DUI) charges.
