Retrieval of analytical data and substance identification in systematic toxicological analysis by the mean list length approach.

Chromatographic techniques are basic tools in systematic toxicological analysis. Extensive data bases with retention parameters of known drugs to aid in the identification of substances found are available or in preparation. For a search in such a data base the computer is indispenable. The commonly used window search has some disadvantages which can be overcome by a search based on the statistical concept, the mean list length. The latter retrieval system gives for each candidate in the identification process a probability value. It is shown that these probability values are highly influenced by the reproducibility of the retention parameters of the analytical systems used. Explanations for these phenomena are given.

System evaluation and substance identification in systematic toxicological analysis by the mean list length approach.

In systematic toxicological analyses (STA), analytical methods are needed with a high Identification Power. The mean list length (MLL) approach, which is an improved and extended version of the Identification Power concept, provides an objective tool for the evaluation and optimum choice of analytical methods for STA. The MLL approach is elucidated and applied to the screening for basic drugs by thin layer chromatography (TLC) and gas-liquid chromatography (GLC). Its usefulness for TLC and GLC systems for the identification of these basic drugs has been evaluated for both single systems and combinations of systems. The MLL approach is also substance directed and can be applied to computerized data searches and substance identification. The method is applicable for single analytical systems and combinations of systems. Mixtures of substances can also be handled.