Assessment of response of the Intoxilyzer 8000C to volatiles of forensic relevance in vitro, part I: acetone, isopropanol, and methanol.

The response of the Intoxilyzer 8000C (version approved for evidentiary breath alcohol testing in Canada) to volatile solvents in vitro is described. Acetone, isopropanol, and methanol were prepared as aqueous solutions or dilutions of standard alcohol solution (SAS; 1.21 mg ethanol/mL) to generate apparent blood ethanol concentrations (aBEC) of 50 or 80 mg/dL. Solvent concentrations examined were relevant to clinical or impaired driving scenarios. Replicates of 20 aBEC measurements were made for each mixture and the actuation of the "INTERFERANT DETECT" message (IDM) was noted. Measurements of aqueous acetone (0-40 mg acetone/dL), isopropanol (0-100 mg isopropanol/dL), and methanol (0-100 mg methanol/dL) yielded aBECs of 0, 0-43, and 0-55 mg/dL, respectively. The minimum concentration examined at which the IDM was actuated in 100% of replicates was 25, 30, and 100 mg/dL for acetone, isopropanol, and methanol, respectively. The maximum concentration examined at which the IDM was actuated in none of the replicates was 5, 10, and 50 mg/dL for acetone, isopropanol, and methanol, respectively. In examinations of acetone/isopropanol mixtures in diluted SAS where the IDM was not always actuated, the maximum BEC overestimation was 10 mg/dL. Overall, the potential for significant undetected BEC overestimation is low and may be further reduced through truncation of test results and subject observation.