In this study, single-use graphite electrodes modified with 5-amino-2-mercapto-1,3,4-thidiazole (AMT) were fabricated for electrochemical monitoring of DNA. The surfaces of AMT modified pencil graphite electrodes (PGEs) were characterized by scanning electron microscopy (SEM). Electrochemical behaviors of these electrodes were investigated using differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). The effects of pretreatment of PGE and immobilization time and concentration of AMT were studied to facilitate an effective immobilization on PGE surface. The efficiency of immobilization is verified by measuring the oxidation signals of either AMT itself or adenine base of DNA, immobilized onto AMT modified electrodes. (C) 2011 Elsevier B.V. All rights reserved.