Analysis of ethambutol and methoxyphenamine by capillary electrophoresis with electrochemiluminescence detection.
A capillary electrophoresis (CE) coupled with electrochemiluminescence (ECL) detection method for the analysis of ethambutol (EB) and methoxyphenamine (MP) has been investigated. Complete separation of EB and MP was achieved in 8 min using a background electrolyte of 20 mM sodium phosphate at pH 10.0 and a separation voltage of 9 kV. ECL detection was performed with an indium/tin oxide (ITO) working electrode biased at 1.4 V (versus a Pt wire reference) in a 200 mM sodium phosphate buffer (pH 8.0) containing 3.5 mM Ru(bpy)3(2+) (where bpy = 2,2'-bipyridyl). Linear correlation (r > or = 0.993) between ECL intensity and drug concentration was obtained in the range 2-50 ng/ml. The limits of detection (LODs) for EB and MP in water were 1.0 and 0.9 ng/ml, respectively. The relative standard deviation values on peak size (10 ng/ml level) and migration time for the two drugs were in the ranges 5-8 and 0.2-0.7% (n = 7), respectively. Applicability of the CE-ECL method to the analysis of human plasma spiked with EB and MP was examined. The LODs for EB and MP in plasma were 0.4 and 0.3 microg/ml, respectively.
Hsieh
Yi-Chien
YC
Department of Chemistry, Tunghai University, Taichung 407, Taiwan.
Whang
Chen-Wen
CW
D019075:Electrophoresis, Capillary / Q000379:methods*; D004977:Ethambutol / Q000032:analysis* / Q000097:blood / Q000737:chemistry; D006801:Humans; D008163:Luminescent Measurements / Q000379:methods*; D008694:Methamphetamine / Q000031:analogs & derivatives* / Q000032:analysis / Q000097:blood / Q000737:chemistry; D015394:Molecular Structure; D015203:Reproducibility of Results
D008694:Methamphetamine; D004977:Ethambutol; C005157:methoxyphenamine