Spectrophotometric determination of trace lead in water after preconcentration using mercaptosephadex

摘要

A highly sensitive and selective spectrophotometric method for determination of trace lead in water after pre-concentration using mercaptosephadex(MS-50) has been developed the method based on the colorreaction of lead (II) with dibromohydroxylphenylporphyrin.Under optimal condition leas(II) reacts with the reagent to form a 1:2 yellow comples in presence of TRITONx-100 which has a maximum absorption peak at 479 nm The color reaction can complete rapidly and remain stable for 24 h in room temperature.The molar absorption coefficient of the lead complex the limit of quantification the limit of detection and relative standard deviations were found to be 2.35 x 10~5 1 mol~-1 cm~-1 4.3,1.4 ng ml~-1 and 1.0% respectively The absorbance of the lead complex at 478 nm is linear up to 0.48 mug ml~-1 of lead(II) The effect of various co-existing ions in water were examined seriously No interference was observed.Moreover a simple pre-concentration method for trace lead in water were examined seriously.No interference was observed.Moreover a simple pre-concentration method for tarace lead in water can be adsorbed in 1.0 mol 1~-1 HCl and dissociated from MS-50 It was found that trace lead in water can be adsorbed in 1.0 mol 1~-1 HCl and sissociated from MS-50 with 4.0 mol 1~-1 HCl quantitatively that improves the selectivity and the sensitivity of method(its detection limit (3 s_ changed into 0.2 ng ml~-1 of lead) obviously.The proposed method had been applied to determine trace lead in water samples with satisfactory results.