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 M nitric acid and plots of ∆A−1r vs. c−1Pb are linear where ∆Ar is the lightabsorption ratio variation and cP b Pb(II) concentration is between 0 and mg/L. The limit of detection (3σ) of Pb(II) is only mg/L. This method was applied to direct analysis of natural water with satisfactory results. |
