EFFECT OF DIFFERENT COLUMNS AND INTERNAL STANDARDS ON THE QUALITY ASSURANCE OF THE GAS-CHROMATOGRAPHIC DETERMINATION OF BLOOD ETHANOL

Quality assurance is an essential requirement of clinical and forensic laboratories, especially in the determination of ethanol. Opinions di ffer as to whether normal gas chromatographic methods should be used w ith modified procedures, or whether different chromatographic strategi es should be adopted, the choice being based entirely on practical con siderations. We have evaluated the influence on the blood ethanol dete rmination of the frequently used glass and steel columns, as well as t he use of isopropanol and tert-butanol as internal standards. All the different combinations of column type and standard provided accurate a nd reliable results with no significant deviation. Standardization of the analytical procedure is therefore unnecessary, but international e thanol standards should be analysed sequentially to test the method an d the staff performing the analyses in the different laboratories.