Evaluation of breath alcohol instruments. I. In vitro experiments with alcolmeter pocket model.
Forensic Sci. 1978 Jul-Aug;12(1):1-9
Authors: Jones AW, Goldberg L
An Alcolmeter Pocket Model breath alcohol device, on an electrochemical (fuel cell) oxidation principle for ethanol analysis, has been evaluated under in vitro conditions. The result of a test is displayed on an analogue meter within 20--30 seconds after sampling: replicate tests may be made within 3--5 minutes. The electrochemical detector used was found to respond to acetaldehyde, methanol, isopropanol and n-propanol vapours besides ethanol, but it was insensitive to acetone vapour. The Alcolmeter response with a 0--2.0 mg/ml scale was linearly related to ethanol vapour concentration up to 1.0 mg/ml blood alcohol equivalent concentration; above this level the response was curvilinear, the Alcolmeter reading being too low. The standard deviation of an ethanol vapour determination in vitro was +/-0.0175 mg/ml at a mean concentration of 0.902 mg/ml. The accuracy of the device expressed as percent recovery at 0.50, 1.0 and 1.4 mg/ml blood alcohol concentrations was 96.8%, 98.3% and 88.3%, respectively. When the Alcolmeter was was calibrated at 0.50 mg/ml and used occasionally each day over an 18-day period, the drop in initial calibration was 0.01 mg/ml per week.
PMID: 711081 [PubMed - indexed for MEDLINE]