MICELLAR ELECTROKINETIC CAPILLARY CHROMATOGRAPHY OF ILLICIT DRUG SUBSTANCES

Micellar electrokinetic capillary chromatography (MECC) was found to give significantly greater efficiency, selectivity, peak symmetry, and speed compared to high-performance liquid chromatography (HPLC) for the determination of illicit drug substances. For a complex mixture consisting of acidic and neutral impurities present in an illicit heroin seizure sample, MECC resolved at least twice as many peaks as HPLC. MECC permitted the analysis of heroin and its basic impurities, the common adulterants phenobarbital and methaqualone, in approximately one-third the analysis time of HPLC with superior resolution. Illicit cocaine, and its basic impurities, were analyzed by MECC without the significant tailing that is found with reversed-phase liquid chromatography (LC) using bonded-phase columns. Other drugs investigated via MECC include opium alkaloids, amphetamines, hallucinogens, barbiturates, benzodiazepines, and cannabinoids. All of these separations were accomplished with 25-100-cm capillaries (length to detector) by using a hydro-organic buffer consisting of 85 mM sodium dodecyl sulfate, 8.5 mM phosphate, 8.5 mM borate and 15% acetonitrile at a pH of 8.5. Detection was by ultraviolet (UV) absorption at 210 nm. Due to its speed, high resolving power, and the probability that all compounds must elute at or before t(mc) (micellar aggregate migration time), MECC is well suited for general drug screening.