Spectrophotometric Determination of Traces of Copper in Water with a New Quarternary Ammonium Salt of Porphyrin

A new chromogenic reagent-5-4-(p-nitro)-benzylammonium pyridyl--10,15,20-tris-(4-N-pyridyl) porphyrin bromide was used to react with Cu(Ⅱ) in a phthalate buffer medium of pH 1.0 to form a coordination complex of molar ratio of 1 to 1.Absorption maximum of the complex lies at the wavelength of 427.0 nm with the molar absorptivity of 1.78×105L·mol-1·cm-1.Linear relationship between values of absorbance and mass concentration of copper was kept in the range within 12 mg·L-1.In the reaction,this new reagent acted not only as a chromogenic reagent but also as a surfactant.Three environmental water samples with known copper contents were analyzed by this method,the results obtained showed average relative deviation less than 3.5% as compared with the known values.