Sensitive and selective nitrite sensor based on phosphovanadomolybdates H6[PMo9V3O40], poly(3,4-ethylenedioxythiophene) and Au nanoparticles

An electrochemical sensor for nitrite based on Keggin-type polyoxometalate H6[PMo9V3O40] (PMo9V3), poly(3,4-ethylenedioxythiophene) (PEDOT) and Au nanoparticles (AuNPs) were fabricated by a combination of electrodeposition with self-assembly approach. The experimental results of cyclic voltammetry (CV) and electrochemical impedance spectrum (EIS) show that this kind of novel and facile strategy endows the composite film sensor faster electron transfer rate, higher electrocatalytic activity to oxidation of nitrite and high stability. The sensing performance of this sensor was explored using current-time test. Wide linear range of nitrite concentration, low limit of detection (LOD) and fast response time were obtained to be 2.5 × 10−9 M-1.43 × 10−3 M and 1.0 × 10−9 M (S/N = 3) and 0.6 s, respectively, which are much better than most as-reported nitrite sensors. This sensor is also free of interference by KBrO3, KIO3, Na2SO4, CaCl2, ascorbic acid and glucose at 0.6-1.0 V. Furthermore, the nitrite sensor was successfully employed for determination of nitrite in five real samples detection, including tap water, mineral water, apple juice, milk and yogurt, with a recovery range of 99.71%-102.64%, which indicates that the sensor can be applied into practical water and drinks detection.