A simple strategy based on lanthanum–multiwalled carbon nanotube nanocomposites for simultaneous determination of ascorbic acid, dopamine, uric acid and nitrite

A simple strategy for simultaneous determination of ascorbic acid (AA), dopamine (DA), uric acid (UA) and nitrite ion (NO2−) based on lanthanum–multiwalled carbon nanotube nanocomposites (La–MWCNTs) modified glassy carbon electrode (GCE) was reported in this paper. Due to the formation of catalytical activity centers, La–MWCNTs display high catalytic activity and selectivity toward the oxidation of DA, AA, UA, and NO2−. And the porosity of La–MWCNTs film and the synergistic effects between lanthanum and MWCNTs were considered as the main reasons of the successfully simultaneous detection. Moreover, because of the excellent film forming ability of the La–MWCNTs nanocomposites, the sensors demonstrated good stability. Cyclic voltammetry, chronoamperometric, transmission electron microscopy and Fourier transformed infrared spectroscopy were employed to characterize the performance and microstructure of the sensor. Under optimal conditions, the linear response range for AA, DA, UA and NO2− are 0.40 μM–0.71 mM, 0.04 μM–0.89 mM, 0.04 μM–0.81 mM and 0.40 μM–0.71 mM, respectively, and the corresponding detection limits are 140 nM, 13 nM, 15 nM and 130 nM (S/N = 3).