[Indirect studies of zinc-histidine complex reaction by FAAS]

Each state of histidine and zinc ion in aqueous solution with different pH was calculated by computer, producing the scatter diagram. Under the influence of solution pH, the mechanism of complex reaction in indirectly determining histidine by flame atomic absorption spectrometry with ZnS was studied. In different state of histidine and zinc ion in aqueous solution at differential pH, the response peak with pH in giving conditions was obtained. The soluble complex ion is composed of 0 valence histidine His+- and -1 valence histidine His+- and Zn(OH)2. The theoretical analysis from computing and scatter diagram agrees very well with the data determined from the experiments. The structures of complex ion are Zn(OH)2 x (C6N3O2H9)2, H8) Zn(OH)2 x [(C6N3O2H8)-]2 and Zn(OH)2 x (C6N3O2H9) x [(C6N3O2H8)-].