A flow injection analysis coupled dual electrochemical detector for selective and simultaneous detection of guanine and adenine

Abstract

Adenine (A) and guanine (G), important bases of nucleic acids, are often analyzed by separation coupled spectroscopic detection methods. Herein, we are demonstrated a new flow-injection analysis (FIA) coupled dual electrochemical detector (DECD), where a chitosan-carbon nanofiber (Chit-CNF) modified glassy carbon electrode prepared by a simple technique and pH 7 phosphate buffer solution as a carrier system, for separation-less quantification of G and A. This method is highly selective and no interference by the presence of the other DNA bases (Thymine and Cytosine). The FIA-DECD was operated at two different operating potentials, E1=0.80V and E2=0.95V vs Ag/AgCl, where G and {G+A} get oxidized, respectively. Amount of A was calculated from the difference between the FIA current signals, measured at E20.95V and E10.80V. The GCE/Chit-CNF was characterized by cyclic voltammetry with potassium ferricyanide system and Raman spectroscopy. The modified electrode showed unique electron-transfer feature with metal like conductivity. Under an optimal condition, FIA-DECD showed linear calibration plots for G and A in a concentration range, 200 nM—50μM with current sensitivity values 13.83±0.48 and 4.84±0.11nA μM−1 respectively. Calculated detection limit (signal-to-noise ratio=3) values were 46.8nM and 73.8nM for G and A respectively. Applicability of the present technique was further demonstrated by detecting G and A in beef kidney sample and DNA hybridization process.