Catalysis reaction between sodium 1,2-naphthoquinone-4-sulfonate and hydroxyl ion using captopril as catalyzer and determination of captopril

• Published in: Analytica chimica acta Vol. 626; no. 2; pp. 174 - 179
• Main Authors: Gao, Linxiao, Wu, Lingli, Li, Quanmin
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 26.09.2008; Elsevier
• Subjects: Analytical chemistry; Angiotensin-Converting Enzyme Inhibitors - analysis; Angiotensin-Converting Enzyme Inhibitors - chemistry; Captopril; Captopril - analysis; Captopril - chemistry; Catalysis; Catalytic reaction; Chemistry; Exact sciences and technology; Hydrogen-Ion Concentration; Hydroxides - chemistry; Mass Spectrometry; Naphthoquinones - chemistry; Sodium 1,2-naphthoquinone-4-sulfonate; Spectrometric and optical methods; Spectrophotometry; Spectrophotometry - methods; Spectrophotometry, Infrared; Sodium 1,2-naphthoquinone-4-sulfonate; Catalytic reaction; Spectrophotometry; Captopril; Correlation coefficient; Drug; Captopril;Sodium;1,2-naphthoquinone-4-sulfonate;Spectrophotometry;Catalytic reaction; Linear regression; Naphthoquinone derivatives; Buffer solution; Sulfonate; Regression coefficient; Absorption spectrometry; Sodium; Detection limit; Reaction mechanism; Catalysis; Hydroxyl
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2008.08.008

A novel and simple spectrophotometric method for the determination of Captopril with sodium 1,2-naphthoquinone-4-sulfonate is established in this paper. The detailed reaction mechanism is proposed and discussed. It is based on the fact that captopril can catalyze the reaction between sodium 1,2-naphthoquinone-4-sulfonate and hydroxyl ion to form 2-hydroxy-1,4-naphthoquinone in buffer solution of pH 13.00. Beer's law is obeyed in a range of 0.64–80 μg mL −1 at the maximal absorption wavelength of 442 nm. The equation of linear regression is A = 0.05815 + 0.00589 C (μg mL −1), with a linear regression correlation coefficient of 0.9981. The detection limit is 0.3 μg mL −1, R.S.D. is 0.77% and the recovery rate is in range of 96.0–103.8%. Furthermore, the method has been validated and successfully applied to the determination of captopril in pharmaceutical samples.