Kompleksi metala i karnozina

In this work electrochemical and spectrometric properties of β-alanine, L-histidine and L-carnosine concentration, c = 1∙\( 10^{-4} \) mol \( dm^{-3}\) as well as complexation of those compounds with copper in ratio 1:1, 2:1, 4:1, 1:2 and 1:4 prepared in buffer pH = 10 were studied. Main purpose of this thesis was to examine complexation of β-alanine, L-histidine and L-carnosine with divalent copper ion, \( Cu^{2+}\) in buffer pH = 10, determine ratio of complexation, investigate influence of the scan rate on the oxido-reduction properties of complexes, study possible adsorption of oxidation product on the surface of the working electrode. Electrochemical properties were investigated by potentiometric titration, cyclic voltammetry and differential pulse voltammetry, while spectrometric with UV/VIS spectrometry. Electrochemical cell for potentiometric measurements was consisted of platinum indicator electrode. Solution of copper nitrite was added in solution of analyte (β-alanine, L-histidine, L-carnosine) and equivalent point was determined instrumentally. Three electrode system with glassy carbon working electrode was used for voltammetric measurements. It was found by potentiometric titration that L-histidine and L-carnosine form complex with copper ion in ratio 1:1 in buffer pH = 10. Cyclic voltammetry showed that β-alanine, L-histidine and L-carnosine were not electroactive and also that there is complexation among L-histidine and copper ion as well as L-carnosine and copper ion from ratio 1:1. Likewise measurements showed that process which undergoes on working electrode is diffusion controlled. Complexation of L-histidine and L-carnosine with copper ion in buffer pH = 10 was confirmed by differential pulse voltammetry as well as that L-histidine and L-carnosine were electroactive and that there was not undergone adsorption of L-histidine, L-carnosine and its complex with copper ion on glassy carbon working electrode.