Spectrophotometric Determination of Lead(II) with meso-Tetrakis(4-chlorophenyl) porphyrin as a Chromogenic Reagent

meso-Tetrakis( 4-chlorophenyl) porphyrin(T ClPP) was used as a novel color reagent for the determination of lead(Ⅱ), and the conditions for the color reaction were studied, including the reation time, the amount of color reagent, buffer solution(N a 2 B 4 O 7-NaOH) and Tween-80.In Na 2 B 4 O 7-NaOH buffer solution of pH=10, a stable complex with the molar ratio [P b( Ⅱ) ∶TClPP] of 1∶1was formed in the presence of Tween-80, with its absorption maximum at 466nm and an apparent molar absorptivity( e) of 2.5×10 5 mol· L-1 ·c m-1.Beer' s Law was obeyed in the range of 160 μg ·L-1 for Pb(Ⅱ). The proposed method was applied to the determination of lead in environmental water samples with satisfactory results.