Capillary electrophoresis coupled with end‐column electrochemiluminescence for the determination of ephedrine in human urine,and a study of its interactions with three proteins |
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Authors: | Ran Yang Hua‐Jin Zeng Jian‐Jun Li Ying Zhang Shi‐Jun Li Ling‐Bo Qu |
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Affiliation: | 1. Department of Chemistry, Zhengzhou University, , People's Republic of China;2. School of Pharmaceutical Sciences, Zhengzhou University, , People's Republic of China;3. College of Chemistry and Chemical Engineering, Henan University of Technology, , Zhengzhou, People's Republic of China |
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Abstract: | A tris(2,2‐bipyridyl)ruthenium(II) (Ru(bpy)32+)‐based electrochemiluminescence (ECL) detection coupled with capillary electrophoresis (CE) method has been established for the sensitive determination of ephedrine for the first time. Under the optimized conditions [ECL detection at 1.15 V, 25 mmol/L phosphate buffer solution (PBS), pH 8.0, as running buffer, separation voltage 12.5 kV, 5 mmol/L Ru(bpy)32+ with 60 mmol/L PBS, pH 8.5, in the detection cell] linear correlation (r = 0.9987) between ECL intensity and ephedrine concentration was obtained in the range 6.0 × 10–8–6.0 × 10–6 g/mL. The detection limit was 4.5 × 10–9 g/mL (S:N = 3). The developed method was successfully applied to the analysis of ephedrine in human urine and the investigation of its interactions with three proteins, including bovine serum albumin (BSA), cytochrome C (Cyt‐C) and myoglobin (Mb). The number of binding sites and the binding constants between ephedrine and BSA, Cyt‐C and Mb were 8.52, 12.60, 10.66 and 1.55 × 104 mol/L, 6.58 × 103 mol/L and 1.59 × 104 mol/L, respectively. Copyright © 2011 John Wiley & Sons, Ltd. |
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Keywords: | capillary electrophoresis (CE) electrochemiluminescence (ECL) tris(2,2‐bipyridyl)ruthenium(II) [Ru(bpy)32+] ephedrine interaction |
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