The use of CE ECL with ionic liquid for the determination of drug alkaloids and applications in human urine

A new approach for the determination of methylephedrine hydrochloride (ME), thebaine, codeine phosphate (CP), and acetylcodeine (AC) was established by CE-ECL with ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate). The conditions for the CE separation, ECL detection, and the effect of ionic liquid were systematically investigated. Under the optimal conditions, the four analytes were well separated within 8 min using 1-butyl-3-methylimidazolium tetrafluoroborate as additive in the electrophoretic buffer. The concentration detection limits of ME, thebaine, CP, and AC were 2.1 x 10(-8), 1.4 x 10(-7), 6.3 x 10(-8), and 3.6 x 10(-8) mol/L (S/N=3), respectively. The LOQs (S/N=10) in real human urine samples were 7.6 x 10(-7) mol/L for ME, 3.6 x 10(-6) mol/L for thebaine, 6.5 x 10(-7) mol/L for CP, and 4.6 x 10(-7) mol/L for AC, respectively. The recoveries of four alkaloids at different levels in human urine samples were between 90.0 and 103.5%. The developed method was successfully applied to the determination of four drug alkaloids in human urine samples.