Polettini A., Groppi A., Stramesi C., Montagna M.

Department of Legal Medicine and Public Health, University of Pavia, Via Forlanini, 12, 27100 Pavia, Italy

The availability of automated, rapid and reliable methods for the systematic toxicological analysis (STA) of drugs and poisons in biosamples is of great importance in clinical and forensic toxicology labs. Among the different proposed approaches to STA, those based on hyphenated techniques have proved to possess the highest potential owing to the large amount of analytical information (both chromatographic and spectral data) that can be collected within a single analysis. HPLC/DAD has been proposed as a technique suitable for STA, its strong points being the possibility of direct analysis of compounds scattered on a wide range of polarity and molecular weight as well as the solvent compatibility of the sample (urine, serum) with the chromatographic system. These features are favourable towards the development of fully automated methods (1). The separation power of capillary GC as well as the selectivity of detection of MS (2) make GC/MS the technique of choice for STA. Furthermore, by including in the proceure a single-step broad spectrum derivatization (3), and a reliable method for the automated detection and identification of unknowns in GC/MS data files (4), most of the weak points of the technique can be easily overcome. As a consequence of the recent introduction of instruments for the automated sample preparation allowing efficient evaporation/derivatization of the extract, full automation of STA methods based on GC/MS analysis is at hand. Using a Hewlett-Packard bench top GC/MS instrument equipped with the HP 7686 PrepStation System, the authors have developed a fully automated procedure involving isolation of drugs from the sample by means of SPE, derivatization of the acidic/neutral and of the basic extracts, GC/MS analysis, processing of data, and reporting of results. The procedure is suitable for the analysis of whole blood with minimal pretreatment consisting of dilution with buffer, sonication and centrifugation. The time required for the completion of one screening, from positioning the sample nto the PrepStation to the printout of the search report is 2.5 h. The capacity of the proposed procedure will be highlighted through examples from real intoxication cases.

References

1. Kalasinsky K.S., Schaefer T., Binder S.R., J. Anal. Toxicol., 1995, 19, 412-418.
2. Maurer H.H., J. Chromatogr., 1992, 580, 3-41.
3. Groppi A., Marrubini G., Polettini A., Montagna M., Proc. 34th T.I.A.F.T. Meeting, Interlaken, 1996. In press.
4. Polettini A., J. Anal. Toxicol., 1996, 20, 579-586.