Spectrophotometric Determination of Trace Copper after Adsorption and Elution of Neocuproine Complex on Chitin

Abstract

An adsorption-elution and spectrophotometric method using chitin was proposed for the preconcentration and determination of copper. Copper is collected as its neocuproine (neoc) complex on a column of chitin in the presence of tetraphenylborate as a counter ion. The copper-neoc complex retained on chitin is eluted with a mixture of acetone and a 1 mol dm-3 acetic acid solution (8:2, v/v) as an eluent, and the absorbance of the eluent is measured at 453 nm. Beer’s law is obeyed over a concentration range of 1.9 to 19.1 μg in 10 cm3 of eluent. Al, Fe(ll), Fe(lll), Co, Ni, Zn, Cd and Pd do not interfere with the determination for concentrations up to 500-times (Mg, Ca and Mn up to 1000-times) that of copper in the presence of EDTA as a masking agent. Common inorganic anions also do not interfere for concentrations up to 10000-times that of copper. The proposed method can be applied to the determination of copper in tap water and standard samples.