Breath alcohols

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. 

Fig. 19.5 Diagram of the infrared analyser nnit of the Lion Intoximeter 3000 breath alcohol analyser. Reprodnced by permission of Lion Laboratories Ltd, Ty Verlon Indnstrial Estate, Barry, Wales CF6 3BE, UK.

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. 

Breath alcohol testing, 72 96 Breathing gases, noble gases as, 77 376-378... 

Over 90% of alcohol consumed is oxidized in the liver much of the remainder is excreted through the lungs and in the urine. The excretion of a small but consistent proportion of alcohol by the lungs can be quantified with breath alcohol tests that serve as a basis for a legal definition of "driving under the influence" in many countries. At levels of ethanol usually achieved in blood, the rate of oxidation follows zero-order kinetics that is, it is independent of time and concentration of the drug. The typical adult can metabolize 7-10 g (150-220 mmol) of alcohol per hour, the equivalent of approximately one "drink" [10 oz (300 mL) beer, 3.5 oz (105 mL) wine, or 1 oz (30 mL) distilled 80-proof spirits]. 

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

Breath alcohol analysis for drink-and-driving legislation... 

Gas analytical instruments for vehicle exhaust emission surveillance, evidential breath alcohol analysis in road traffic and calorific value determination of fuel gases are subject to legal control and require type approval and initial and subsequent verification. The national standards required in this part of gas analysis are provided by BAM. PTB uses in-house standards prepared by dynamic blending to ensure traceability of its type approval... 

Ethanol in air mixtures as standards for the new generation of evidential breath alcohol analysers. 

Cooper S. 1981. Infrared breath alcohol analysis following inhalation of gasoline fumes. J Anal Toxicol 5 198-199. 

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... 

During the period of active alcohol absorption (30 to 120 minutes before peak venous blood alcohol concentration), the alcohol concentration in arterial blood may be higher than that in peripheral venous blood. Consequently, breath alcohol concentration may also be higher than that in venous blood during this absorption phase, because end-expiratory air equilibrates with pulmonary arterial blood. The potential consequences of performing breath alcohol analysis during the absorption phase have been the subject of considerable debate. ... 

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. 

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. 

Jones AW. Pharmacokinetics of ethanol in saliva comparison with blood and breath alcohol profiles, subjective feelings of intoxication, and diminished performance. Clin Chem 1993 39 1837-44. 

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. 

Features. A series of boxed and highlighted Features are found throughout the text. These essays contain interesting applications of analytical chemistry to the modern world, derivation of equations, explanations of more difficult theoretical points, or historical notes. Examples include Breath Alcohol Analyzers (Chapter 7), Antioxidants (Chapter 20), Fourier Transform Spectroscopy (Chapter 25), LC/MS and LC/MS/MS (Chapter 32), and Capillary Electrophoresis in DNA Sequencing (Chapter 33). 

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

Gill R, Hatchett SE, Broster CG, et al. 1991. The response of evidential breath alcohol testing instruments with subjects exposed to organic solvents and gases. I. Toluene, 1,1,1 -trichloroethane, and butane. Med Sci Law 31 187-200. 

---