Abstrato

A Rapid Spectrophotometric Method For Determination Of Nickel In Industrial, Environmental, Biological And Soil Samples Using Bis(Salicylaldehyde)Orthophenylenediamine

M.Jamaluddin Ahmed, Khandakar Jakir Hossain, M.Iqbal Bhanger

A very simple, ultra-sensitive and fairly selective spectrophotometric method is presented for the rapid determination of nickel at trace level using Bis(salicylaldehyde)orthophenylenediamine(BSOPD). The method is based on the reaction of non-absorbent BSOPD in a slightly acidic(5.0 ×10-3- 1.5×10-2 M H2SO4 ) and 50 %(v/v) N,N-dimethylformamide (DMF) media with nickel(II) to produce a highly absorbent red-yellow chelate-product that has an absorption maximum at 466 nm. The reaction is instantaneous and the absorption remains stable for 24 h. The apparent molar absorption coefficient and Sandell’s sensitivity were found to be 6.01×104 L mol-1 cm-1 and 7ngcm-2 of nickel(II) respectively. Linear calibration graphs were obtained for 0.02 – 10.0 mgL-1 of NiII, the stoichiometric composition of the chelate is 1:1(BSOPD : NiII). A large excess of over 50 cations, anions and complexing agents(e.g. EDTA, tartrate, oxalate, citrate, phosphate, thiocyanate etc.) do not interfere in the determination. The method was successfully used for the determination of nickel in several standard reference materials(brass, steels and alloys) as well as in some environmental waters (portable and polluted) biological (human blood and urine) and soil samples and complex synthetic mixtures. The method has high precision and accuracy(s = ± 0.01 for 0.5 mg L-1).