A novel sensor based on Fe3O4 nanoparticles–multiwalled carbon nanotubes composite film for determination of nitrite

A novel nitrite sensor was constructed via electropolymerization of l-cysteine on the multiwalled carbon nanotubes and then immobilization of cationic poly(diallyldimethylammonium chloride) coated Fe3O4 nanoparticles through electrostatic interaction at glassy carbon matrix. Under the optimized conditions, the obtained sensor exhibited good electrocatalytic activity for the oxidation of nitrite, and the peak current of nitrite increased linearly with its concentration from 7.49 × 10−6 to 3.33 × 10−3 mol/L (R = 0.9998) with the detection limit of 8.46 × 10−7 mol/L (S/N = 3). Moreover, the sensor exhibited good sensitivity, stability and repeatability with potential applications.