This invention provides approaches to improve the signal to noise ratio (S/N) in electrochemical measurements (e.g., amperometry, voltammetry, etc.). In particular, a method is described wherein the faradaic current is temporally dissociated from the charging current associated with reading the charge of a redox-active species (e.g., a self-assembled monolayer (SAM)). This method, designated herein as open circuit potential amperometry (OCPA), quantitatively reads the charge of the redox species bound to (electrically coupled to) an electrode surface, while discriminating against both charging current(s) and amperometric signal(s) that arise, e.g., from diffusion-based species in solution.