Pedro RomeroJosé M. AbadLenys FernándezOlga M. BelandriaVı́ctor M. Fernández2026-03-222026-03-222008http://erevistas.saber.ula.ve/index.php/avancesenquimica/article/download/6419/6231https://andeanlibrary.org/handle/123456789/63580Influence of state oxidation of cobalt ion in the stability electrodes modified with monolayers SAM-TOAANTA-Con+-HRP-NHis.Quartz Crystal Microbalance (QCM) was used to investigate the adsorption of the HRP-NHis enzyme (horseradish peroxidase), which was modified by the addition of a tail of six histidine on its extreme Nterminal.The QCM operating at flow of 0.025 mL min-1 on a crystal whose gold electrode was modified with monolayers of SAM-TOA-ANTA-Co2+ and SAM-TOA-ANTA-Co3+. The oxidize form was obtained from the electrochemical oxidation of a monolayer of SAM-TOA-ANTA-Co2+. The results suggest that the HRP-NHis is attached to both monolayers in a similar way; on the contrary, the desortion of the attached protein is dramatically different. Thus, whereas the ligand-Co2+ bonds are reversible, which allows that the anchored protein is easily replacedby imidazol molecules. The 3+ oxidation state of the metal does not allow the interchange of protein by the imidazol molecules.enQuartz crystal microbalanceMonolayerChemistryElectrodeHorseradish peroxidaseSelf-assembled monolayerElectrochemistryCobaltOxidation stateMoleculearticle