Analytical Sciences

Abstract − Analytical Sciences, 19(5), 731 (2003).

Catalytic Flow-Injection Determination of Sub-ppb Copper(II) Using the Redox Reaction of Cysteine with Iron(III) in the Presence of 2,4,6-Tris(2-pyridyl)-1,3,5-triazine
Jiatai WEI, Norio TESHIMA, Shinsuke OHNO, and Tadao SAKAI 
Department of Applied Chemistry, Aichi Institute of Technology, 1247 Yachigusa, Yakusa-cho, Toyota 470-0392, Japan
A kinetic-catalytic spectrophotometric flow-injection method was developed for the rapid and sensitive determination of trace amounts of copper(II). The method is based on the catalytic effect of copper(II) on the redox reaction of cysteine with iron(III). Iron(II) produced by the catalytic reaction reacts with 2,4,6-tris(2-pyridyl)-1,3,5-triazine (TPTZ) to form the iron(II)-TPTZ complex (λmax = 593 nm). By measuring an absorbance of the complex, one could determine 0.05 - 8 ppb copper(II) with the relative standard deviations (n = 10) of 1.6%, 1.3%, and 0.8% for 0.5 ppb, 1 ppb, and 2 ppb copper(II), respectively. The limit of detection (S/N = 3) was 0.005 ppb. The sample throughput was 30 h-1. The proposed method was successfully applied to the determination of copper in natural water and serum samples.