A glassy carbon electrode modified with poly(2,4-dinitrophenylhydrazine) for simultaneous detection of dihydroxybenzene isomers

2,4-Dinitrophenylhydrazine (DNPH) was electropolymerized on the surface of an anodized glassy carbon electrode by cyclic voltammetry. The anodized electrode has a highly electroactive surface due to the creation of chemically functionalized graphitic nanoparticles, and this facilitates the formation of poly-DNPH via radical polymerization. Poly-DNPH displays excellent redox activity due to the presence of nitro groups on its backbone. These catalyze the electro-oxidation of hydroquinone (HQ) and catechol (CT). The peak-to-peak separation is around 109 mV, while a bare GCE cannot resolve the peaks (located at 165 and 274 mV vs. Ag/AgCl). Sensitivity is also enhanced to similar to 1.20 and 1.19 mu A.cm(-2).mu M-1, respectively. The sensor has a linear response that covers the 20-250 mu M concentration range for both HQ and CT, with 0.75 and 0.76 mu M detection limits, respectively, at simultaneous detection. Commonly present species do not interfere.