Problems of Forensic Sciences 2001 Vol. 46 (XLVI) 326-332
INTER- AND INTRA-INDIVIDUAL VARIATIONS OF BLOOD/BREATH AND SALIVA/BREATH RATIOS OF ALCOHOL
Wojciech GUBAŁA1, Dariusz ZUBA2
1Institute of Forensic Research, Cracow, Poland
2Faculty of Chemistry, Jagiellonian University, Cracow, Poland
Streszczenie
The research was aimed at verification of possibility to use saliva for alcohol determination as exact equivalent of blood samples or exhaled breath. Breath analysis is used in Poland and some other European countries (e.g. in Belgium, Czech Republic, Italy, Norway, and Portugal) as an indirect method of determination of blood alcohol concentration, expressed in g/l. The constant value of a blood/breath ratio of alcohol assumed for that purpose is doubtful because of dynamics of gas exchange processes in air passages. In view of this the inter- and intra-individual variations in the blood/breath and saliva/breath ratios of alcohol have been estimated. 23 persons have taken part in 34 experiments. 7 persons of them have participated at least 2 times. Men drank 0.70 g and women 0.60 g of ethanol per kilogram of body weight as neat vodka. Saliva, breath and blood profiles were monitored at 15 minutes intervals for up to blood alcohol concentration measured using Alcomat fell below 0.20 g/l. Blood- and saliva- ethanol concentrations were determined with gas chromatography using Perkin-Elmer Autosystem equipped with headspace autosampler HS 40. The alcohol concentrations indicated by Alcomat were converted into breath alcohol concentrations, expressed in mg per litre of breath, according to the conversion factor (2100:1) applied in the devices.
The blood/breath and saliva/breath ratio of alcohol concentration for every sampling time was calculated for each examined person. The calculation gave 450 values of the distribution ratio of alcohol for each system. Finally, analysis of variance was used for comparison of the inter- and intra-individual variations in these ratios. The value of the blood/breath ratio for respective person averaged from 1553 to 2506. The relative standard deviations (RSD) of these values amounted from 6.1–30.3%. These great intra- and inter-individual variations indicate lack of possibility of universal blood/breath ratio application. The intra-individual variations were lower for saliva/ breath ratio of ethanol and RSD amounted from 5.1–19.0%.
Słowa kluczowe
Alcohol; Blood/breath ratio; Saliva/breath ratio; Ratio variations. Problems