Breathalyzer® Tests with the Equilibrator and the Effect of room Temperature

Abstract

Statistical treatment of the data relating ka/w to temperature for dilute aqueous ethanol solutions suggests that 1n ka/w is not linearly related to temperature as has recently been reported. The relationship:ka/w = 0.0000326 e(0.0840T–0.000318T2)yields calculated values of ka/w that fall within ± 1 × 10-6 of the experimental range (T in °C).Tests utilizing an equilibrator and an aqueous alcohol solution (3.41 mg/mL) indicate that higher than expected results will be obtained on a Borkenstein Breathalyzer if the ambient temperature is higher than the solution temperature and lower results will be obtained if the ambient temperature is lower than the solution temperature. Maximum differences were—16 mg/100 mL when ambient temperature was 10.6°C cooler than the solution and 12 mg/100 mL when ambient temperature was 9.9°C warmer than the solution. Condensation was present in the outlet tube of the equilibrator during all tests where the solution was warmer than the room (N-36).