Uv-vis identification of copper complexes with inhibitor organic components in the electrolyte

The UV-VIS method is an effective, non-destructive method that enables a better understanding of the electrolyte during corrosion. The aim of the study presented in this paper is to determine the existence of an organometallic complex in a 0.5 M NaCl solution with the addition of Rubus fruticosus L. leaf extract (RFLE). The experiments were conducted in a 0.5 M NaCl solution with the addition of RFLE (5 g/L and 10 g/L) with and without the immersion of a copper coupon. The results show that after the copper coupon standing in the electrolyte, there is a change in the absorbance maximum in the solution with 5 g/L RFLE, while no change is observed in the solution with 10 g/L RFLE. Such a change indicates the existence of a copper-RFLE complex in the solution with lower inhibitor concentration. In the case of RFLE, forming a copper complex with caffeic acid, isoquercetin and astragalin is possible. The absence of the complex at a concentration of 10 g/L RFLE can be attributed to a change in the mechanism and the lack of copper ions in the solution due to adequate corrosion protection.