Study of Purge Readings and the Reproducibility and Accuracy for Repeated Sampling of Standard Vapours With the Breathalyzer

• NCJ Number: 93345
• Journal: Canadian Society of Forensic Science Journal Volume: 16 Issue: 4 Dated: (December 1983) Pages: 192-197
• Author(s): N K Shajani; B P Samija
• Date Published: 1983
• Length: 6 pages
• Publication Format: Article
• Language: English
• Country: Canada

Annotation

This paper reports experiments dealing with purge readings and the reproducibility and accuracy of results obtained using the Breathalyzer, models 900 and 900A, and standard vapours from a simulator.

Abstract

The mean value of the first purge was found to be 5.64 mg% and the mean value of the second purge was found to be 3.92 mg%. No negative values were found. Thus, the start line used during a Breathalyzer test will subtract this blank value. The Breathalyzer was found to underestimate the value of a simulator solution in almost all cases, except at relatively low concentrations. The results obtained utilizing relatively low concentrations to relatively high concentrations were found to be linear. The error associated with the Breathalyzer, described as being plus or minus 10 mg%, was found to be acceptable at levels between 50-300 mg%. (Publisher abstract)