A novel electrochemical DNA biosensor based on poly-(5-amino-2-mercapto-1,3,4-thiadiazole) modified glassy carbon electrode for the determination of nitrofurantoin

In this study, poly(5-amino-2-mercapto-1,3,4-thiadiazole) (PAMT) modified glassy carbon electrode (GCE) was fabricated and this electrode was used for the electrochemical monitoring of interaction between the dsDNA and nitrofurantoin (NFT) for the first time. Electrochemical behavior of PAMT modified GCE (GCE/PAMT) was investigated by using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) and compared with those of the bare GCE. The GCE/PAMT/dsDNA electrode was prepared by adsorption of dsDNA upon the PAMT deposited the GCE and the binding of NFT with dsDNA was investigated via differential pulse voltammetry (DPV) method. The decrease in the guanine oxidation peak current at +0.82 V was used as an indicator for the interaction in 0.5 mol L-1 acetate buffer (pH 4.8) containing 0.02 mol L-1 NaCl. Under the optimal conditions, the guanine oxidation peak currents were linearly proportional to the concentrations of NFT in the range of 2-25 mg L-1 and detection limit was found to be 0.65 mg L-1. Furthermore, the reproducibility, repeatability, stability and applicability of the analysis to pharmaceutical dosage forms in human serum samples were also examined. These results showed that this DNA biosensor could be used for the sensitive, accurate and precise determination of NFT-dsDNA interaction. (C) 2014 Elsevier B.V. All rights reserved.