Saliva as an alternate for blood to measure concentrations of acetone under exposure to isopropanol.

OBJECTIVES

In occupational medicine, blood concentrations are often measured to judge the internal burden of workers at work-place during exposure to a potentially hazardous substance. However, blood-withdrawals are invasive and can often not be taken at work-place due to hygienic reasons. Sampling of saliva is non-invasive and easy to perform even at workplace. In order to substitute blood analysis, analysis of saliva has to be as specific and sensitive as blood investigations. Therefore acetone-concentrations in blood and in saliva during exposure to isopropanol were compared.

METHODS

18 healthy non-smokers were exposed to 360 ppm isopropanol in an exposure chamber over 4 h. Once an hour during exposure and 30 min after, blood and saliva were sampled. Saliva was collected by a cotton plug over 10 minutes and stored in an airtight closed headspace tube. Concentrations of the metabolite acetone were measured by gas chromatography. -

RESULTS

The concentrations of acetone in blood and saliva rose continually during exposure and dropped after exposure-cessation. High correlations between concentrations of acetone in blood and saliva were found for each individual and the entire group (entire group: r = 0.8568, p <0.0001, y = 0.8374x - 0.4404).

CONCLUSIONS

Acetone-measurement in saliva is a non-invasive, easily conductable and reliable method for estimating the internal burden of isopropanol-exposure. Further studies for the standardization and validation are necessary to impose a threshold limit value on work-place isopropanol-exposure.