A rapid and sensitive method for the analysis of three catecholamines by capillary electrophoresis （CE） with direct chemiluminescence （CL） detection is described. The detection limits （S/N= 3） were 1.3 × 10^-8 g/mL for isoprenaline, 1.0 × 10^-8g/mL for epinephrine and 2.8 × 10^-8 g/mL for dopamine. The proposed method was successfully applied to the analysis of catecholamines in urine samples of cigarette smokers and nonsmokers. The results showed that there is a close relation between the release of dopamine in human body fluids and cigarette smoking/nonsmoking.
A new method for sensitive and rapid indirect electrochemiluminescence(IECL)detection of norepinephrine(NE),synephrine,and isoproterenol with capillary electrophoresis(CE)was developed.IECL detection is based on their quenching effects on Ru(bpy)2+3/tripropylamine(TPA)system.Under the optimum conditions,the detection limits(S/N=3)were 2.6×10-8 mol/L for NE,6.6×10-9 mol/L for synephrine,and 8.4×10-8 mol/L for isoproterenol.The RSD of migration time and peak area were less than 1.3% and 4.4%,respectively.The proposed method was successfully applied to the analysis of NE in the urine samples of 10 healthy people and 10 diabetic nephropathy patients.The results indicate that the content of NE in diabetic nephropathy patients is much higher than that in healthy people.
A novel method for the determination of two quinolone drugs norfloxacin （NOR） and levofloxacin （LVX） was described by capillary electrophoresis with electrochemiluminescence detection. The good relationship （r ≥ 0.9991） between peak area and concentration of analytes was established over two orders of magnitude. The limits of detection （LOD, S/N = 3） in standard solution are 4.8 × 10^-7 mol/L for NOR and 6.4 × 10^-7 mol/L for LVX, respectively. The limits of quantitation （LOQ, S/N = 10） in real human urine samples are 1.2 × 10^-6 mol/L for NOR and 1.4 × 10^-6 mol/L for LVX, respectively. The present method was successfully applied to the determination of NOR and LVX in human urine and the studv of oharmacokinetics of NOR.
It was found that 20 amino acids could inhibit the intensity of the luminol-H_2O_2-CuSO_4 chemiluminescence system.Using this character,a rapid and sensitive method for the determination of 20 amino acids was developed with flow injection coupled with chemiluminescence detection.Under the optimal conditions,the detection limits of 20 amino acids were in the range of 4.5×10^（-7）- 4.3×10^（-10） mol/L,and the relative standard deviations were less than 3.2%.The proposed method was successfully applied to drug analysis.The possible mechanism was also discussed.
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,BMIMBF4). The conditions for the CE separation,ECL detection and the effect of ionic liquid(IL) were systematically investigated. Under the optimal conditions,the four analytes were well separated within 8 min using BMIMBF4 as additive in the electrophoretic buffer. The concentration detection limits of ME,thebaine,CP,and AC were 2.1×10-8,1.4×10-7,6.3×10-8,and 3.6×10-8 mol/L(S/N=3),respectively. The limits of quantitation(LOQ,S/N=10) in real human urine samples were 7.6×10-7 mol/L for ME,3.6 ×10-6 mol/L for thebaine,6.5×10-7 mol/L for CP,and 4.6×10-7 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.
