Catalytic determination of iodide by a maximum absorbance method using the oxidation reaction of chlorpromazine with hydrogen peroxide

✍ Scribed by Bing Liang; Susumu Kawakubo; Masaaki Iwatsuki; Tsutomu Fukasawa

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 608 KB
• Volume: 282
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/0003-2670(93)80355-o

✦ Synopsis

Chlorpromazine is oxidized catalytically in the presence of iodide with 1 M hydrogen peroxide in 1 M sulphuric acid medium to form a red radical, which is further oxidized to a colourless sulphoxide. The plot of absorbance at 528 nm vs. reaction time shows an absorbance maximum proportional to the concentration of iodide ions in the range O-7 ng ml-'. The method has the advantage that careful control of the reaction time and temperature is not needed, the reaction temperature has little influence on the detennination in the range 20-WC. The method also gives a higher sensitivity and shows less influence of the concentrations of hydrogen peroxide and sulphuric acid than the tangent method using the initial reaction. The limit of detection is about 0.1 ng ml-' (0.5 ng in 5 ml of measured solution). The effects of foreign ions were investigated. The mechanism of the reaction is discussed.