TNT determination based on its degradation by immobilized HRP with electrochemical sensor

Abstract Based on the mechanism of 2,4,6-Trinitrotoluene (TNT) degradation, an amperometric hydrogen peroxide biosensor was constructed for the determination of trace amounts of TNT by immobilization of MWCNTs, HRP and Nafion onto the surface of glassy carbon electrode (GCE). The Nafion/MWCNTs/HRP biosensor was capable of degrading TNT with the consumption of H 2 O 2 and HRP in 0.2 mol/L PBS (pH 7.0). Trace TNT was quantitative analyzed by the current decrease of H 2 O 2 at the reductive potential of −0.35 V using cyclic voltammetry (CV). Effect of the ratio of MWCNTs/HRP, initial concentration of H 2 O 2 and electrolyte’s pH were also optimized by CV. Under the optimal conditions, the current decrease of H 2 O 2 that was consumed by TNT degradation was proportional to TNT ranging from 8.8 × 10 −9  mol/L to 2.64 × 10 −7  mol/L with a detection limit of 3.0 × 10 −9  mol/L (S/N = 3). It developed a new way for simple, rapid and sensitive measurement of trace TNT.