TY - JOUR PY - 1981// TI - Breath-alcohol analysis after sorption on calcium sulfate. In-vitro and in-vivo studies JO - Proceedings International Council on Alcohol, Drugs and Traffic Safety Conference A1 - Dubowski, Kurt M. SP - 637 EP - 647 VL - 1981 IS - N2 - We evaluated breath-alcohol analysis by automated gas chromatographic headspace analysis after intervening sorption of ethanol on calcium sulfate (dubowski,k, clin chem 23:1371, 1977). In-vitro accuracy and precision was examined in precision-simulator effluents. Alcohol was measured, in divided breath specimens from 43 healthy adult subjects, directly with a model 900-a breathalyzer and by automated gc headspace analysis of calcium sulfate eluates. In-vitro results of vapour-alcohol analysis (n=22) for target values of 0.05-0.30 g/210 l in 0.05 steps were (mean + or - sd): 0.051 + or - 0.0009, 0.100 + or - 0.0011, 0.149 + or - 0.0026, 0.194 + or - 0.0027, 0.254 + or - 0.0043, and 0.304 plus or minus 0.0036 g/210 1. The system met US Dept of Transportation in-vitro standards for quantitative evidential devices (fed reg 34:30459, 1973). In-vivo studies yielded brac differences (n=703) between breathalyzer tests and gc analyses of calcium sulfate (mean + or - sd) of +0.00063 + or - 0.00757 g/210 l over a 0-0.16 g/210 l range; maximum difference was +0.025 and only 6 differences exceeded + or - 0.020 g/210 l. The best fit least-squares linear regression equation for the paired in-vivo results was y=0.949x + 0.00333, r=0.969 for 745 (including 42 "blank") data pairs, where y=brac by calcium sulfate analysis and x=brac by breathalyzer model 900-a in g/210 L, r=pearson correlation coefficient. Brac's in alcohol-free subjects were uniformly negative. No change occurred in the ethanol quantity sorbed on calcium sulfate during 11 months of storage. We conclude that there is no significant difference between breath-alcohol analysis results obtained by direct measurement and after calcium sulfate sorption. (TRRL)

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