Use of β-cyclodextrin in the capillary zone electrophoretic separation of the components of clandestine heroin preparations

The present paper describes the methodological optimization and validation of a capillary zone electrophoresis method for the rapid determination of heroin, secondary products and additives present in clandestine heroin samples, by using 20 mM β-cyclodextrins in phosphate buffer, pH 3.23. Applied potential was 15 kV and separation temperature was 24°C; detection was by UV absorption at 200 nm wavelength. Heroin samples were first dissolved in CHCl3–MeOH (96:4, v/v) and injected by pressure (0.5 p.s.i., 3 s; 1 p.s.i.=6894.76 Pa) after evaporation of the organic mixture and reconstitution in aqueous buffer. Under the described conditions, phenylethylamine (internal standard), morphine, monoacetylmorphine, heroin, acetylcodeine, papaverine, codeine and narcotine were baseline resolved in less than 10 min. The limit of detection was better than 1 μg/ml for each analyte. The study of the intra-day and day-to-day precision showed, in terms of migration times, RSDs ≤0.71% and, in terms of peak areas, RSDs ≤3.2%. Also, the evaluation of linearity and analytical accuracy of the method provided good results for all the analytes investigated, thus allowing its application to real cases of seized controlled drug preparations.