Forensic chemist, Criminal Identification Division, National Police Headquarters, Jerusalem,
(Received 14 November 1985; accepted 7 March 1986)
Cocaine hydrochloride salt (HCl) and heroin HCl were determined quantitatively by choosing a carbonyl absorption peak as the analytical peak and measuring absorbance versus concentration in standard KBr pellers. The effect of various additives and diluents such as starch, sugars, mannitol, caffeine, and procaine was also studied. Methods were devised to correct for interference contributions based on spectral subtraction of the interfering component or subtraction of the interfering spectral contribution based on absorbance ratios with a noninterfering spectral peak. In mixtures containing both the free base and the hydrochloride salt, the most satisfactory method for determining the concentration was by area integration of the two carbonyl peaks.
Paper ID: JFS12323J