关键词: 锌络合物, 稳定常数, 脉冲极谱法, 紫脲酸铵, 分析

Murexide yields a well-defined derivative pulse polarographic peak in concentration larger than 1.7X10**-4M, but a post peak in adsorption character appears in concentration less than 1.7X10**-4M. When murexide concentration is 1.6X10**-5M, the main peak decreases with increasing pH and turns into a negative one after pH 5.48. It can be suppressed apparently by gelatin. This is a new adsorption plenomenon showing the complexity of murexide adsorption. Murexido may form complex with zinc ion. They together yield five peaks and show the adsorption phenonmenon. The stability constant of zinc-murexide complex is calculated to be logβ=3.4 at given conditions (pH=5.95, 25`C). The mechanism of complex formation and adsorption process is discussed.

Key words: ZINC COMPLEX, STABILITY CONSTANT, PULSE POLAROGRAPHY, MUREXIDE, ANALYSIS