Problems of Forensic Sciences 2002 Vol. 51 (LI) 7-28
THE USEFULNESS OF THE THIN-LAYER CHROMATOGRAPHY METHOD IN THE IDENTIFICATION OF COCAINE AND ITS METABOLITE BENZOYLECGONINE IN AUTOPSY MATERIAL
Marianna KISZKA, Roman MĄDRO
Chair and Department of Forensic Medicine, Medical Academy, Lublin
Streszczenie
The usefulness of thin-layer chromatography (TLC) in the identification of cocaine (C) and benzoylecgonine (BE) in urine and tissues was evaluated. The possibility of separating C from BE as well as both of these compounds from the “biological background” and also the sensitivity of different staining systems were studied. To this end, 30 developing systems were examined, four of which (methanol-chloroform 4:1, ethyl acetate-methanol-ammonia 60:30:6, chloroform-methanol-ammonia 100:20:1, chloroform-methanol-ammonia-water 70:30:1:0.5) were assessed as optimal for the analysis of extracts from the liver and the kidney due to good separation of the investigated xenobiotics from the “biological background”. For the analysis of urine extracts, the first three systems out of those mentioned above and the mixture chloroform-methanol 4:1 turned out to be the best. In the search for optimal developing systems, lidocaine (LD) was also considered, as good separation of it from C and BE was achieved, e.g. in the systems methanol-chloroform 4:1 and 1:4. However, separation of cocaethylene (CEt) from C was not entirely satisfactory – only after using a hexane-toluene-diethylamine system 65:20:5 a moderate differentiation of Rf was achieved, i.e. 0.48 and 0.42, respectively. It was also found that the best system for staining chromatograms (from among 20 examined ones) is a combination of Dragendorff’s reagent with a solution of sulphuric acid (because it dyes about 1 μg of C or BE in a spot). However, the “background” of the autopsy material influenced the sensitivity of the detection.
Słowa kluczowe
Cocaine; Benzoylecgonine; Thin-layer chromatography; Determination; Autopsy material.