A glassy carbon electrode modified with porous Cu2O nanospheres on reduced graphene oxide support for simultaneous sensing of uric acid and dopamine with high selectivity over ascorbic acid

Porous cuprous oxide nanospheres were deposited on reduced graphene oxide (pCu 2 O NS-rGO) by a solvothermal approach that uses hexadecyltrimethylammonium bromide as the capping agent and L -glutamic acid as the reducing agent. The nanomaterial was characterized by transmission electron microscopy, Raman spectroscopy, thermogravimetry, and electrochemical methods. A glassy carbon electrode was modified with pCu 2 O NS-rGO, and the respective electrode displays a well expressed oxidation peak for dopamine (DA) located at 160 mV (vs. SCE). It also gives a strong peak for uric acid (UA) which is separated from the DA peak by 130 mV (vs. SCE). No signals can be detected for ascorbic acid (AA) in concentrations up to 2.0 mM. The findings are exploited in a method for simultaneous determination of UA and DA. The linear ranges are from 1.0 to 138 μM for UA, and from 0.05 to 109 μM for DA even in the presence of relatively high concentrations of AA. The detection limits are 112 nM for UA and 15 nM for DA (at an S/N ratio of 3). Porous cuprous oxide nanospheres deposited on reduced graphene oxide was fabricated by a one-pot solvothermal method. The nanocomposites were explored to construct a sensor for simultaneous determination of uric acid and dopamine in the presence of ascorbic acid with high concentration.