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device used by police to determine the amount of alcohol in the system of persons suspected of being intoxicated. In the analyzer, a precise amount of the suspect's exhaled breath is passed through a solution of potassium dichromate and sulfuric acid; the change in the colour of the solution is proportional to the amount of alcohol in the air sample, which, in turn, is directly related to the alcohol content of the blood. Driving ability is seriously impaired when the alcohol concentration in the blood exceeds 80 milligrams per 100 millilitres.