[The liquid scintillation counting of the 14C natural level in ethanol: a comparison of different standardisation methods (author's transl)].

The influence on liquid scintillation counting efficiency of internal standards toluene-14C, hexadecane-14C and ethanol-14C has been studied for low level-14C measuring of ethanol samples. Many biological and synthetic samples of ethanol have been counted: the best results are obtained with external standardisation on quenching calibration curve made with ethanol-14C. External standardisation on quenching calibration curve made with toluene-14C is preferable to internal standardisation with ethanol-14C. Hesadecane-14C as internal standard gives activities rather higher than true values.