Problems of Forensic Sciences 2001 Vol. 48 (XLVIII) 7-30
EVALUATION OF THE METHOD OF COCAINE AND BENZOYLECGONINE ISOLATION FROM POST-MORTEM MATERIAL. PART I: LIQUID-LIQUID EXTRACTION
Marianna KISZKA, Roman MĄDRO
Chair and Department of Forensic Medicine, Medical Academy, Lublin
Streszczenie
The effectiveness of cocaine (C) and benzoylecgonine (BE) isolation using LLE: one- and three-step extractions and in a continuous system was studied. The highest C recovery from aqueous solutions was achieved in the pH range 7–11 while for BE no clear optimum pH was observed. In the one-step extraction, recovery of C was high while that of BE low. BE recovery increased, however, with an increase in the amount of solvent and with addition of alcohol, and also after salting out the samples, but this resulted in higher levels of impurities in the extracts. The mixture dichloromethane-isopropanol (3:1) was found to be the optimum one for the threestep LLE of urine samples. With the sample/solvent ratio ranging from 1/5 to 1/8, C recovery was 57–69% and BE recovery – 39–50%. Moreover, the extracts were of high purity (suitable for HPLC analysis). The extraction in a continuous system was characterised by high recovery (68–75% of C and 72–80% of BE from deproteinised homogenates of the kidney); however, it depended on the quality of solvents and was limited to the pH range 7–8, and, furthermore, prior to their analysis (HPLC method), the extracts required purification (TLC method).
Słowa kluczowe
Cocaine; Benzoylecgonine; Liquid-liquid extraction; Autopsy material.