Elimination of the background signal in tooth enamel samples for EPR-dosimetry by means of physical-chemical treatment

A method of elimination of the background EPR signal in tooth enamel is pro posed. This method implies treatment of enamel powder by highly active redu ction reagent hydrazine with subsequent washing out by ethanol-water soluti on. Such treatment results in reducing both the native background signal (w hich is assumed to be originated by the organic component) and the mechanic al induced EPR signal in enamel. Testing of the efficiency of hydrazine tre atment is made for different sizes of enamel powder. It is shown that the o ptimal results are obtained for a powder fraction of about 100-200 mum. The radiation-induced EPR signal in enamel is practically not changed after tr eatment by hydrazine. (C) 2001 Published by Elsevier Science Ltd.