Non-enzymatic amperometric sensor of catechol and hydroquinone using Pt-Au-organosilica@chitosan composites modified electrode

An amperometric non-enzymatic sensor based on Pt-Au-organosilica@chitosan (Pt-Au-OSi@CS) composites has been developed for determining catechol (CC, 1,2-dihydroxybenzene) and hydroquinone (HQ, 1,4-dihydroxybenzene). The Pt-Au-OSi@CS composites were synthesized using positively charged inorganic–organic core–shell organosilica@chitosan (OSi@CS) crosslinked nanospheres as templates for the assembly of negatively charged 1–3 nm Au nanoparticles seeds which acted in subsequent step as nucleation sites for the reduction of platinum. Due to the excellent electrocatalytic response of Pt-Au-OSi@CS for the reduction of CC and HQ, the sensor based on the Pt-Au-OSi@CS exhibited broad linear range of 0.06–90.98 μM for CC and 0.03–172.98 μM for HQ. The low detection limits of 0.02 and 0.01 μM (S/N = 3) were obtained for CC and HQ, respectively. The operational conditions were optimized. The sensitivities of the non-enzyme electrode for CC and HQ were 307.95 μA mM−1 cm−2 and 1714.20 μA mM−1 cm−2, respectively.