The present paper aims to find a method of comprehensive characterisation and definition of complex mixtures. For this purpose the technique of spectral fingerprint shows most advantages. It has been applied to the definition of very similar herbal antitussic preparations containing an extract from the plantain plant (Plantago lanceolata). The synchronous fluorescent spectrum (Dl = 15 nm), in contrast to the classic emission spectrum, can resolve the individual preparations. The complete characteristic of the preparation is, however, provided only by the method of a special fluorescent fingerprint, which developed from a combination of the technique of recording synchro- nous spectra with a programmably changeable difference in Dl and the computer processing of graphic records in the form of contour maps. The combination makes it possible to graphically define and characterise complex mixtures, the exact composition of which may not be even known. The method can be used in the analysis of pharmaceutical, food, cosmetic and other products, in the control of their quality, observance of the technological process, in the comparison of identical products by different manufacturers as well as in revealing counterfeit brand products. Spectral fluorescent fingerprints – contour fluorescent maps can be stored in a database and they posses the same informational value as fingerprints in criminological practice.

        Key words: synchronous spectrum – fluorescent fingerprint – contour maps – phytopharmaceuticals