Chemistry

Chemistry

Chemistry

Question 1: Explain why it is necessary to have a robust and accurate method to determine blood ethanol levels

The robustness of a test system would be important for many reasons. For example, if a test was being carried out off-site by a portable method it would be very important for the test system to be able to function correctly and consistently in changeable conditions (i.e. temperature). Accuracy in any test system is of great importance (Canfield & Kupiec, 1993: 914). 

There are various means of determining an individual's BAC level, the most common and inexpensive of which is by measuring the alcohol in an exhaled sample of breath, BrAC (Jones, 1990). Law enforcement personnel can administer this test quickly on the scene when alcohol intoxication is suspected. Other tests measure alcohol content in bodily fluids and are generally carried out in clinics or laboratories. While blood samples offer a more reliable measure of alcohol content, both urine and blood samples are less practical from an enforcement point of view as they do not provide immediate results (Currier, Trenton, & Walsh, 2006). In addition, in the time needed to reach a clinic or other testing sites, an individual's BAC may drop, resulting in a lower reading.

As with alcohol's effect on the body in general, BAC levels are influenced by a number of factors that include drinking patterns (Gentry, 2000a, 2000b; Kalant, 2000; Li et al., 2000; Stimson, Grant, Choquet, & Garrison, 2007; Stockley & Saunders, 2010; Thomasson, 2000). How much alcohol an individual has consumed and over what period of time determine BAC levels as functions of absorption and metabolism rates. A drinker's weight, gender, health, and food intake affect the levels of blood alcohol that are reached (see ANNEX 1: The Basics about Alcohol). In general, BAC increase is less rapid with greater body weight and with food intake, and is less rapid in men than in women.

Question 2: Briefly describe the principles of the main technique used as cited in this paper.

Estimates of percent body fat were calculated using body circumferences or skinfold measurements. Subjects were dosed with .68 g alcohol/kg bodyweight, and the relationship of BAC to body fat estimate was analyzed. Use of body fat estimates did not increase the accuracy of BAC estimates sufficiently to recommend the method. It may be useful for scientific purposes but appears not to be feasible for widespread use (Briglia & Bidanset, 1992: 991). The data suggest that compared to men, women will achieve the same BAC with 15% less alcohol, based on ounces of alcohol per pound bodyweight. Similarly, the overweight person will achieve the same BAC as the average weight person with 10% less alcohol. These recommendation reflect the male-female differences in body composition, and the higher percent body fat in the obese body.  

  Estimates of blood alcohol concentration (BAC) typically are based on the amount of alcohol consumed per pound bodyweight.. This method fails to consider either food intake or body composition, factors which significantly affect ...