AN OVERVIEW ON THE STANDARDIZATION OF CHROMATOGRAPHIC METHODS FOR SCREENING ANALYSIS IN TOXICOLOGY BY MEANS OF RETENTION INDEXES AND SECONDARY STANDARDS .1. GAS-CHROMATOGRAPHY

In systematic toxicological analysis, in which a logical analytical search for a potentially harmful substance has to be carried out, chromatographic methods are of utmost importance since the retention parameter can be used for primary identification. In gas chromatography the Kovats retention index (RI) system is generally accepted for standardization of the retention. In order to increase the reproducibility of the interlaboratory RI, secondary standards for RI calculation have proven to be very useful. The best secondary standards are those that are structurally resembling the substances under investigation. For example, for general toxicological screening analysis, mixtures of drugs are recommended. Stationary phases consisting of Carbowax are most extensively used for solvents and volatile compounds; for less volatile compounds SE-30/OV-1/dimethylsilicone stationary phases have proven to be useful. For these types of stationary phases extensive data compilations comprising over 6000 substances are available for use in toxicology.