Breath alcohol measurement

Approximately 5%-10% of ethanol is excreted unchanged in the breath and urine. The blood-to-breath ratio of ethanol is 2,000 to 1, an important relationship that permits blood alcohol determination from expired air, providing the basis for the use of breath alcohol measurement for clinical, research, and forensic applications. 

Several commercial evidential breath alcohol measurement devices are available. The principle of measurement is either infrared absorption spectrometry (most common), dichromate-sulfuric acid oxidation-reduction (photometric), GC (flame ionization or thermal conductivity detection), electrochemical oxidation (fuel cell), or metal-oxide semiconductor sensors. A list has been published of DOT-approved breath alcohol devices.Some of these devices are approved for screening only. In this case, the second or confirmatory breath alcohol determination must be performed with an approved evidential breath alcohol analyzer. Breath alcohol devices may also be used for the medical evaluation of patients at the point of care (e.g., emergency department). A Fourier transform infrared point-of-care breath analyzer capable of measurement of... 

Jones AW (Reply by Simpson G). Concerning accuracy and precision of breath-alcohol measurements. Clin Chem 1987 33 1701-6. 

One way of testing for tetrachloroethylene exposure is to measure the amount of the chemical in the breath, much the same way breath alcohol measurements are used to determine the amount of alcohol in the blood. This test has been used to measure levels of the chemical in people living in areas where the air is contaminated with tetrachloroethylene or those exposed to the chemical through their work. Because it is stored in the body s fat and is slowly released into the bloodstream, it can be detected in the breath for weeks following a heavy exposure. Tetrachloroethylene can be detected in the blood. Also, breakdown products of the chemical can be detected in the blood and urine of people exposed to tetrachloroethylene. Trichloroacetic acid (TCA), a breakdown product of tetrachloroethylene can be detected for several days after exposure. These tests are relatively simple to perform. The breath, blood, or urine must be collected in special... 

This graph shows that with an assumed specificity of 70%, a sensitivity of 90% is achieved. The estimated BACs based on breath alcohol measurement were validated by blood sample analysis at the end of the trial. 

Breath alcohol testing is accompHshed by a number of techniques. The oldest rehable procedure involves bubbling a measured volume of deep-lung air containing alcohol through an acidic solution of potassium dichromate, Deep-lung air is the last portion of expired breath. It is collected in... 

It is simpler and quicker to measure a suspect s breath alcohol concentration (BrAc). This can be converted to BAC by multiplying by 2100 one volume of blood contains about 2100 times as much alcohol as the same volume of breath. In practice, this calculation is done automatically in the instrument used to measure BrAc it reads directly the BAC of 0.05%. 0.08%. or whatever. 

The equation shows that alcohol in the form of ethanol reacts with an orange solution of potassium dichromate to produce a green solution of chromic sulfate. The source of alcohol is the suspect s breath. More alcohol produces a greater color change. The breath analyzer measures this color change and coverts this measurement into an amount of alcohol in the blood. 

Figure 7.8. A possible metrological traceability chain for the result of a breathalyzer measurement of a motorist s breath alcohol.

Similar techniques are used to measure alcohol in blood, serum, saliva, or urine and for postmortem specimens (e.g. vitreous fluid and skeletal muscle). Determination of ethanol in expired air requires specialized breath alcohol analyzers (see section on Breath Alcohol). 

Statutory laws for driving under the influence of alcohol were originally based on the concentration of ethanol in venous whole blood. Because the collection of blood is invasive and requires intervention by medical personnel, the determination of alcohol in expired air has long been the mainstay of evidential alcohol measurements.There is also growing clinical interest m the determination of breath alcohol at the point-of-care. The fundamental principle for use of breath analysis is that alcohol in capillary alveolar blood rapidly equilibrates with alveolar air in a ratio... 

Jones AW. Measuring ethanol in saliva with the QED enzymatic test device Comparison of results with blood and breath alcohol concentrations. J Anal Toxicol 1995 19 169-74. 

Transportation Department, National Highway Traffic Safety Administration. Highway safety pro-grams Model specifications for devices to measure breath alcohol. Fed Reg 2002 67 62091-4. 

Begg TB, Hill ID, Nickolls LC (1964) Breathalyzer and Kitagawa-Wright methods of measuring breath alcohol. Br Med J 1(5374) 9-15... 

When a driver is arrested for suspicion of driving under the influence of alcohol, the blood alcohol content is determined to see if it exceeds the legal limit. The measurement of breath alcohol is usually done for routine driving arrests because it is noninvasive, and a factor is applied to convert to blood alcohol concentration (BAG). But this is subject to biological variations in individuals. In cases where there is an accident, injury, or death, the blood alcohol is usually determined directly, by analyzing a blood sample by gas chromatography. 

One such portable instrument that is based on IR for measuring breath alcohol is the Intoxilyzer-8000 from CMI. It uses dual wavelengths for measurement and takes less than one minute to deliver a result. When the performance of the protable Intoxilyzer-8000 (7.7 kg) was compared with that of the approved stationary Intoxilyzer-5000 instrument (13.6kg), it was shown that the portable instrument performed well enough to be used for evidential breath alcohol testing. ... 

A person is arrested by police and taken to the police station where the alcohol concentration in her breath is measured as equivalent to 100 mg ethanol per 100 ml of blood, (a) What official statement of alcohol concentration would be made by a forensic scientist (b) Estimate the BAG three hours after the measurement. 

Breath alcohol was measured using the Alcotest 7110 Evidential MK III (Drager Safety, Lubeck, Germany). 

First, BIS and BAC reference measurements were made during the first 30 min. Then, 120 ml of vodka (40% abv) was imbibed followed by a resorption phase of 50 min. After this initial phase, all measurements were made and an amount of 60 ml of vodka was imbibed by the subjects followed again by 50 min resorption phase. This cycle was repeated for as long as the subject had not reached a breath alcohol level of 0.4 mg/1, assuming a BAC of 0.8%o. Thus, after the initial baseline measurement, up to 4 measurement cycles were performed. After a subject dropped out of the study, a blood sample of 3 ml was taken as reference. The total trial time was 180 min. 

Concerning the clinical trial, significant changes for all examined values were analyzed with a focus on measurement point 0 and 3. The extracellular resistance showed the best performance. Figure 6 presents the calculated R and measured breath alcohol concentration over the measurement period for one representative subject. 

Figure 6. and breath alcohol concentration for one subject over the measurement period. 

This study examined the feasibility of using BIS to assess the BAC. For this, 12 adult males drank alcohol up to a BAC of 0.8%o BIS was then measured up to 4 times during the trial to calculate the body composition. In addition, to vahdate the alcohol measurements, BAC was measured in parallel using a breath alcohol detector as reference. 

Specifically, detector tubes operating on eolorimetrie reaetion principles have been used to determine the eoneentration of aleohol in breath for traffic safety. Alcohol measurements in breath have been flioroughly studied and scrutinized because of the forensie... 

Potassium dichromate oxidation of ethanol to acetic acid is the basis for the original breath alcohol screening test used by law enforcement agencies to determine a person s blood alcohol content. The test is based on the difference in color between the dichromate ion (reddish orange) in the reagent and the chromium(lll) ion (green) in the product. Thus, color change can be used as a measure of the quantity of ethanol present in a breath sample ... 

Both tests measure alcohol in the breath.The legal definition of being under the influence of alcohol is based on blood alcohol content, not breath alcohol content. The chemical correlation between these two measurements is that air deep within the lungs is in equilibrium with blood passing through the pulmonary arteries, and an equilibrium is established between blood alcohol and breath alcohol. It has been determined by tests in persons drinking alcohol that 2100 mL of breath contains the same amount of ethanol as 1.00 mL of blood. 

As a matter of procedure tihe measurement of drivers BAG is most often not based on direct measurement of the blood content. Instead drivers are asked to blow into a portable breath tester and their lung air is analyzed. Because the breath alcohol concentration is proportional to the BAG by a factor of 2.2727 (Vanlaar, 2005), the breath alcohol content can be easily converted into blood alcohol concentration. For example, a breath alcohol concentration of 0.22 mg alcohol per liter of exhaled air is equivalent to 0.5 g/1 in the blood, or 0.05% BAG. 

Breath-alcohol test, given to measure blood alcohol concentration (BAC). 

Specifically, detector tubes operating on colorimetric reaction principles have been used to determine the concentration of alcohol in breath for traffic safety. Alcohol measurements in breath have been thoroughly studied and scrutinized because of the forensic and legal repercussions associated with the results. Portable devices have been developed for field use with on-site analysis of alcohol. These portable devices eould be adapted for use with other organic solvents of interest in industrial hygiene and occupational health. 

Visual spectroscopy can also be semiquantitative. A simple example is the assessment of swimming pool water quality and its chemical content using well-known color reactions and simple sets of colored concentration reference standards. This evaluation of light or color intensity is called photometry. Visual photometry saw one early use in criminal law with the evaluation of breath alcohol concentrations. The test was based on the ability of breath alcohol to chemically reduce the colored chromate ion to a colorless form in aqueous solutions. As more alcohol vapor was bubbled through a chromate solution it became more bleached. The resulting solution was then visually compared to a calibrated, standard set of diluted chromate solutions to determine the subject s breath alcohol content. The test was soon modified to include instrumental measurement of the decolorizing reaction and is referred to as a form of spectrophotometry. 

Alcohol. The number of driving under the influence of alcohol (DUl) cases reflects the enormity of the dmnken driving problem in the United States (9). Tests to measure blood alcohol concentration are conducted on blood, urine, or breath (10). In the case of urine and breath, the alcohol concentration measured is reported in terms of the equivalent blood alcohol concentration. Most states in the United States presume that a person is under the influence of alcohol with respect to driving a motor vehicle at a blood alcohol concentration of 0.10%, ie, an ethanol concentration >10 g/100 mL of blood. Some states maintain a lower necessary concentration of 0.08%. In some European countries levels are as low as 0.05%. A blood alcohol concentration of 0.10% in a 68-kg (150-lb) person is the equivalent of about four drinks of 80 proof alcohoHc beverage or four 340-g (12-oz) beers in the body at the time of the test (see Beer Beverage spirits, distilled Wine). Ethanol is metabolized at the equivalent rate of about one drink per hour. 

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