Determination of amlodipine using terbium‐sensitized luminescence in the presence of europium(III) as a co‐luminescence reagent |
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| Authors: | Salma M Z Al‐Kindy Abdalla Al‐Snedi Fakhr Eldin O Suliman Haidar A J Al‐Lawati |
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| Affiliation: | Sultan Qaboos University, College of Science, Box?36, Department of Chemistry, Al‐Khod, Sultanate of Oman |
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| Abstract: | A sensitive time‐resolved luminescence method for the determination of amlodipine (AM) in methanol and in aqueous solution is described. The method is based on the luminescence sensitization of terbium (Tb3+) by formation of a ternary complex with AM in the presence of tri‐n‐octylphosphine oxide (TOPO) as co‐ligand, dodecylbenzenesulfate as surfactant and europium ion as a co‐luminescence reagent. The signal for Tb–AM–TOPO is monitored at λex = 242 nm and λem = 550 nm. Optimum conditions for the formation of the complex in aqueous system were 0.015 m Tris (hydroxylmethyl) amino methane buffer, pH 9.0, TOPO (1.0 × 10–4 m ), Eu3+ (2.0 × 10–7 m ), dodecylbenzenesulfate (0.14%) and 6.0 × 10–5 m of Tb3+, which allows the determination of 10–50 ppb of AM with a limit of detection of 1.2 ppb. The relative standard deviations of the method range between 0.1 and 0.2% indicated excellent reproducibility of the method. The proposed method was successfully applied for the assay of AM in pharmaceutical formulations and in plasma samples. Average recoveries of 98.5 ± 0.2% and 95.2 ± 0.2% were obtained for AM in tablet and plasma samples respectively. Copyright © 2013 John Wiley & Sons, Ltd. |
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| Keywords: | sensitized luminescence amlodipine plasma pharmaceutical products co‐luminescence |
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