Problems of Forensic Sciences 2005 Vol. 63 (LXIII) 288-298
ASSESSMENT OF THE EFECTIVENESS OF DENATONIUM BENZOATE (BITREX) REMOVAL FROM DENATURED SPIRIT PREPARATIONS USING SODIUM HYPOCHLORITE
Dariusz ZUBA, Czesława ŚWIEGODA, Bogumiła BYRSKA, Wojciech LECHOWICZ
Institute of Forensic Research, Krakow
Streszczenie
The aim of the study was to assess the effectiveness of purification of spirit preparations denatured by Bitrex by means of sodium hyphochlorite. The subject matter was chosen following analysis of evidential material submitted to the Institute, which indicated that such a process might be applied by companies trading in products prepared on the basis of alcohol, e.g. windscreen washers, disinfectants, alcoholic solvents, or barbecue lighting fluid. High-performance liquid chromatography (HPLC) was used in the analysis and the obtained results were confirmed by means of mass spectrometry (MS). The addition of sodium hypochlorite to spirit preparations causes the formation of a white precipitation, the amount of which increases together with an increase in the amount of sodium hypochlorite added to the solution. An increase in the amount of added sodium hypochlorite causes a decrease in the concentration of denatonium benzoate. Introduction of sodium hypochlorite at a concentration of 12–15% active chlorine in an amount corresponding to 0.05 ml per 1 litre of spirit denatured by Bitrex at 3 mg/l caused a decrease in denatonium ions concentration in the solution, whereas addition of an amount corresponding to 0.20 ml/l of spirit caused its disappearance. The lack of denatonium ions in the solution meant that the concentration of Bitrex in the solution was below the limit of detection and, thus, it was practically removed. Such a small addition of sodium hypochlorite does not significantly influence the pH of the solution. Disappearance of denatonium ions also caused a disappearance of the characteristic bitter taste of Bitrex, which was assessed by means of an organoleptic examination. Addition of the mentioned amounts of sodium hypochlorite did not cause a decrease in the concentration of benzoate ions. Since consumer (beverage) spirits do not contain benzoate ions, their detection in a seized alcoholic beverage indicates with high probability that it was previously denatured by Bitrex. The benzoate ions can also be removed from solution by addition of sodium hypochlorite, but the amount required in this case is significantly higher: approximately 80 ml per 1 litre of spirit denatured by 3 mg of Bitrex. In this case, the pH of the solution is significantly raised (pH = 11–12), which makes it unsuitable for consumption. Such a product would have to be further purified before being introduced onto the illegal market.
Słowa kluczowe
Denatured alcohol; Denatonium benzoate; Removal.