Methods and insulator electrode devices for performing electrochemical reactions are disclosed. The devices consist of high specific surface area electrodes based on a channeled conducting base material that has been coated with an organic or inorganic insulating film or multiple layers of such films. The chemical reactions are exemplified by exciting one or several label compounds into an excited state which is spontaneously de-excited by emission of ultraviolet, visible or infrared light, in aqueous solution. This provides the basis for reproducible analytical applications in bioaffinity assays such as immunoassays and DNA-probing assays.