Spectrophotometric determination of trace amounts of cadmium using <i>m</i>-nitrobenzenediazoaminoazobenzene

Abstract

The spectral correction technique has been applied for the determination of cadmium using <i>m</i>-nitrobenzenediazoaminoazobenzene (<i>m</i>-NBDA). The composition ratio, real absorptivity and stepwise stability constant of the Cd-<i>m</i>-NBDA complex have been studied. The ratio of Cd to <i>m</i>-NBDA is found to be 1:3, its cumulative stability constant is 9.30×10¹⁸ and its real absorptivity

is 1.36×10⁵ mol^-1cm^-1 at 460 nm. Beer's law is obeyed over the range of 0 - 25μ g Cd(II)/25ml, the detection limit of cadmium is found to be 0.006 mg/l and the relative standard deviation is 4.5%.