Determination of trace heavy metals in waters by flame atomic absorption spectrometry after preconcentration with 2,4-dinitrophenyldiazoaminoazobenzene on Amberlite XAD-2

摘要

A new column,solid-phase extraction(SPE),preconcentration method was developed for determination of Cd,Co,and Cu ions in natural water samples by flame atomic absorption spectrometry.The procedure is based on the retention of analytes in the form of 2,4-dinitrophenyldiazoaminoazoben-zene(DNDAA)complex on a mini column of DNDAA-XAD-2 resin.The effects of pH,eluent type,eluent concentration,eluent volume,resin quantity,sample volume,sample flow rate,and matrix ions(Na,Ca,and Mg)were investigated on the recovery of the metals using model solutions.The detection limit for Cd,Co,and Cu was 0.062,0.084,and 0.057 mu gL~(-1),and the quantification limit was 0.17,0.24,and 0.12 mu gL~(-1),respectively.The method was validated by the analysis of a certified reference material with the results being in agreement with those quoted by manufactures.The developed method was applied to the determination of trace metal ions in tap water,river water samples with satisfactory results.