Determination of Pb(II) in natural water with dibromo-p-methyl-sulfonazo by the light-absorption ratio variation approach

Authors: JIE ZHANG

Abstract: Pb ions can react sensitively with dibromo-p-methylsulfonazo (DMSA) to form a blue complex, whose absorption is maximal at 630 nm. By means of the light-absorption ratio variation approach (LARVA), the direct determination of Pb was developed in 0.3 M nitric acid and plots of \Delta A_r^{-1} vs. c_{Pb}^{-1} are linear where \Delta A_r is the light-absorption ratio variation and c_{Pb} Pb(II) concentration is between 0 and 5.0 mg/L. The limit of detection (3\sigma) of Pb(II) is only 0.02 mg/L. This method was applied to direct analysis of natural water with satisfactory results.

Keywords: Light-absorption ratio variation, spectrophotometry, dibromo-p-methylsulfonazo, determination of Pb(II), natural water

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