Rapid and Sensitive Voltammetric Detection of Rhodamine B in Chili-Containing Foodstuffs Using MnO2 Nanorods/Electro-Reduced Graphene Oxide Composite

A facile voltammetric sensor based on MnO2 nanorods/electro-reduced graphene oxide composite modified glassy carbon electrode (MnO2NRs-ERGO/GCE) was proposed for the detection of Rhodamine B (RhB). The MnO2NRs-ERGO/GCE was fabricated by a facile drop-casting approach followed by a potentiostatic reduction technique. A well-shaped oxidation peak of RhB was observed at the MnO2NRs-ERGO/GCE, and the response peak current was 17-fold and 2-fold higher than that of bare GCE and ERGO/GCE respectively, attributing to the synergistic electrocatalytic effect from ERGO sheets and MnO2NRs. Under the optimal analytical conditions, the response peak currents linearly increased with the RhB concentrations varying from 0.02 μM to 1.0 μM and from 1.0 μM to 20 μM. The limit of detection (LOD, S/N = 3) was 6.0 nM. Furthermore, the MnO2NRs-ERGO/GCE showed good selectivity, repeatability, reproducibility and stability. Finally, the MnO2NRs-ERGO/GCE was successfully employed to detect RhB in different commercial chili-containing foodstuffs, and the results were in good accordance with the values that detected by high-performance liquid chromatography. Combining with low cost and portable electrochemical apparatus, the proposed sensor is especially suitable for the in-situ detection of RhB in actual food samples.