Hemin-Modified Halloysite Nanotube as Electrocatalyst for the Enhanced Electrochemical Determination of Nitrite

Halloysite is naturally occurring nanotubular clay with a phyllosilicate structure and widely used as solid support to modify various redox mediators. We prepared hemin modified halloysite (Hemin/HNT) by simple impregnation method, in which known amount of was dispersed ethanolic solution 1% reacted for 12 h. The resulting pure Hemin/HNT employed electrocatalyst the electrochemical oxidation nitrite cyclic voltammetry. coverage molecule over confirmed TGA, FT-IR, XRD XPS studies. electron transfer behavior studied CV EIS. It noted that hemin/HNT GCE showed two-fold enhanced peak current potential + 0.8 V vs Ag/AgCl 0.1 M PBS. For quantitative analysis ion at trace levels differential pulse voltammetry (DPV) amperometry methods were based on GCE. A linear calibration plot constructed plotting against concentrations ranges 0.6 × 10 −6 24.6 −5 M, (R 2 = 0.9968) −8 43.3 −7 0.9996) detection limit found be 42 43 nM sensitivity 23.55 22.96 μ A. −1 .cm −2 DPV amperometry, respectively. repeatability proposed sensor evaluated terms relative standard deviation 1.7% 5 measurements (3.3 M) nitrite. inference effect anions cations method. stable reliable response obtained water samples.