Determination of trace amount of cu(ii) using 3’, 5’-dinitro salicyaldehyde semicarbazone as an analytical reagent by solvent extraction and spectrophotometric method

A simple precise spectrophotometric method is coupled with solvent extraction technique used for determination of Cu(II) with 3’,5’-Dinitro Salicyaldehyde Semicarbazone [3’,5’DNSAS]as an analytical reagent. Reagent forms a complex with Copper metal producing a yellow coloured stable complex which can be quantitatively extracted into n-butanol at pH 7.8. The absorption spectrum of Cu(II) : 3’,5’DNSAS complex in n-butanol exhibits an intense absorption peak at 350 nm. The study of changes of colour intensity of copper with varying concentration of reagent showed that 1.0 cm3 of 0.1% reagent is sufficient for full colour development of extraction of 100 ppm copper solution. The extraction was observed to be quantitative for equilibrium time even less the 60 seconds and absorbance of extracted species showed stability upto 28 hours. Beer’s law is obeyed. Stoichiometric ratio of complex studied by job’s continuous method, mole ratio and slope ratio method. The composition observed was 1:1. The molar absorptivity and Sandell’s sensitivity are also calculated. The newly developed method has been successfully applied for the analysis of copper in synthetic samples and alloys.