SOFT/TIAFT 98 - Headspace GC and Headspace SPME/GC-MS Investigation of Hydrolyzed Hair ...

SOFT - TIAFT 1998

Poster Session 3

Thursday October 8, 1998

HEADSPACE GC AND HEADSPACE SPME/GC-MS INVESTIGATION OF HYDROLYZED HAIR SAMPLES OF ALCOHOLICS, SOCIAL DRINKERS AND TEETOTALERS

Fritz Pragst, Frank Sporkert and Katharina Spiegel

Institute of Legal Medicine, Humboldt-University, Hannoversche Straße 6, D-10115 Berlin, Germany

In order to investigate, whether a steady high alcohol consumption leads to an increasing incorporation of endogenous or nutritive products containing ethyl groups into hair or to a chemical binding of ethyl groups onto hair constituents, hair samples of 50 alcoholics, 10 social drinkers and 10 consequent teetotalers were washed with water and CH₂Cl₂, carefully dried, hydrolyzed with 30% NaOH at 80 °C in closed vessels and analyzed by headspace GC and headspace-solid phase micro extraction (SPME)/GC-MS with t-butanol as internal standard. The following volatile compounds were identified: ethanol (17 - 60 ng/mg), acetone (85 - 230 ng/mg), butan-2-one (4 - 18 ng/mg), a series of further alkane-2-ones and in some cases nicotine.

By preceding 24 h extraction with methanol or aqueous buffer at pH 7.6 in an ultrasonic bath up to 60 % of the ethanol producing compounds were removed from the hair matrix. From the methanol extracts 0 - 12 ng/mg ethanol were formed by hydrolysis after evaporation of methanol and drying. There was no significant difference in the amount of ethanol detected in hydrolyzed hair samples or hair extracts between alcoholics and social drinkers, whereas slightly smaller concentrations were detected in abstinent children's hair. No significant influence of age, sex or hair color was observed.

For identification of extractable ethanol precursors hair extracts were analyzed by GC/MS-SIM for ethyl esters of 15 endogenous or nutritive carboxylic acids after adequate sample preparation. Out of these only p-hydroxybenzoic acid ethyl ester (0.1 - 5.9 ng/mg) as a usual preserving agent in hair care products has been identified, the concentration of which is by far too small to explain the total amount of ethanol formed.

As a conclusion, ethanol liberated from hair by alkaline hydrolysis does not prove chronically elevated alcohol consumption.

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