Spectrophotometric Determination of Trace Lead Using Meso-tetra-(3-methoxy-4-hydroxyphenyl-Tb³⁺ Porphyrin

A spectrophotometric determination of trace Lead using T-(3-MO-4-HP) P-Tb as a chromogenic reagent has been systematically studied. The results showed that the chromogenic reaction was complete under the following conditions: pH = 4.95 of a HAc-NaAc buffer solution, AOT microemulsion, and a heating of 4 min in a boiling water bath. At the maximum absorption wavelength of 478 nm, the molar absorption coefficient was 7.49×10⁵ L/(mol·cm). Beer's law was obeyed in the concentration range of 0.0~0.2 μg/mL for lead II. This method is of high sensitivity, good selectivity, and can be applied to the determination of trace lead(II) in water sample with satisfactory results.