Kinetic spectrophotometric method for gold(III) determination

• Published in: Analytica chimica acta Vol. 547; no. 1; pp. 144 - 149
• Main Authors: Rancic, Sofija M., Nikolic-Mandic, Snezana D., Mandic, Ljuba M.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 15.08.2005; Elsevier
• Subjects: Analytical chemistry; Anti-rheumatic drug; Chemistry; Exact sciences and technology; Gold(III); Spectrometric and optical methods; Spectrophotometric kinetic method; Urine; Gold(III); Urine; Anti-rheumatic drug; Spectrophotometric kinetic method; Atomic emission spectrometry; Selectivity; Inductive coupling plasma spectrometry; Basic dye; Detection limit; Standard curve; Standard deviation; Oxidation; Trace analysis; Correlation coefficient; Human; Drug; Catalytic reaction; Kinetic method; Gold III; Reaction rate; Methylene blue; Thiazine dye; Linearity; Thermodynamic parameter; Kinetic parameter; Signal to noise ratio; Ultraviolet visible spectrometry
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2004.11.078

The kinetic spectrophotometric method for Au(III) determination was developed and validated. It was based on the catalytic effect of gold on the oxidation of methylene blue B (3,7di-(dimethyl amino)-10-dehydro-phenotiazin chloride) by ammonium peroxo-disulfate in citric buffer solution. There was the linearity of the calibration curve in the concentration range from 0.09 to 2.90 μg ml −1 Au(III). The relative standard deviation was 2.50% and correlation coefficient of 0.9999. The limit of detection was determined as signal to noise ratio (3:1) and it was 5.5 ng ml −1. The limit of quantification, based on signal to noise ratio 10:1 was 19.25 ng ml −1. The selectivity was tested on the basis of influence of known amounts of different ions in the reaction mixture, upon the reaction rate. Kinetic and thermodynamic parameters were reported for both catalytic and non-catalytic reactions. The method was verified by Au(III) determination in anti-rheumatic drug “Tauredon” and in human urine samples, using ICP–AES as the comparative method. As the method is accurate, reliable, quick and simple it could be useful for clinical and toxicological practice.