The novel analytical model to analyze oligopeptides sensing is based on the self-consistent solution of Gouy-Chapman-Stern and Site-Binding model (SB) - . SB model explains the probability of the immobilized oligopeptides on the oxide surface resulting in terms of surface charge density (σo). σo depends on the active surface states (NS), bulk pH (pHB) and dissociation constants (Ka, Kb, Kc & Kd) of the active sites on the oligopeptides , - . Here, we have used 4 combinations of both tripeptides immobilized by carboxylic terminal to account for the addition, substitution, and mutation of the considered tripeptides. Every combination corresponds to a different σo considering the active sites (amine site and sidechains) [IPP ( ), RIPP ( ), DPP ( ), RDPP ( ), LKP ( ), RLKP ( ), DKP ( ), RDKP ( ) where R: Arginine & D: Aspartic Acid] except the affinity of the carboxylic site reacted in the immobilization with the linker.