||Several chemically modified electrodes (CMEs) were developed in order to get high performance electrochemical sensors for the determination of biologically important redox-active species. Chapter 1 is a brief summary of the background and the current hotspots of chemically modified electrodes (CMEs) closely related to the main focus of this thesis, especially CMEs with inorganic materials. Chapter 2 describes the modification of electrodes in solution containing CrCl3, K2PtCl6 and KCl by cyclic voltammetry. UV-visible spectroscopy, AFM and XPS were carried out to characterize the inorganic film, and the film was denoted as [Cr2(PtCl6)3]n. We studied the electrochemical behavior of the modified electrode in electrolyte solutions containing various cations, such as H+, Fe3+. This modified electrode also displays a very good catalytic activity toward the determination of hydrogen peroxide and nitric oxide. In chapter 3, an inorganic film was electromodified onto the electrode substrates (GC or ITO) by cyclic voltammetry in solution containing K3RuCl6, Pt(NH3)4Cl2 and KCl. The modifed electrodes were characterized by UV-visible spectroscopy, XPS and AFM, and the film is denoted as Pt(NH3)4Cl2-RuOx. The film of Pt(NH3)4Cl2-RuOx shows excellent electrocatalytic ability in the oxidation of ascorbic acid, the oxidation and reduction of hydrogen peroxide and nitric oxide. Chapter 4 reports the preparation, characterization and electrcatalytic properties of electrodes modified with Ru2[-O(CN)4CrOCr(CN)4O-]. UV-visible spectroscopy, AFM, XPS and ToF-SIMS were conducted for the film characterization. The electrocatalytic behavior of Ru2[-O(CN)4CrOCr(CN)4O-]/GC was studied in detail, including the reduction of hydrogen peroxide, the oxidation of ascorbic oxide and nitric oxide. Chapter 5 focuses on the development of layer-by-layer self-assembly multilayer films based on mix-valences hydrous transition metal oxides. The inorganic films were characterized by UV-visible spectroscopy, AFM, XPS and electrochemistry. Spectroelectrochemistry, which couples the UV-visible absorption with electrochemistry, was employed to study the reversible electrochromatic behavior of the multilayer films. The modified electrode displays electrocatalytic activity in the reduction of H2O2 and oxidation of ascorbic acid.