Construction of an ultra-sensitive electrochemical sensor based on polyoxometalates decorated with CNTs and AuCo nanoparticles for the voltammetric simultaneous determination of dopamine and uric acid.

A composite modified electrode was prepared based on α-K7P2VW17O62·18H2O (P2W17V), CNTs and AuCo nanoparticles (AuCo NPs), and used as a structurally stable and highly sensitive electrochemical sensor for simultaneous determination of dopamine (DA) and uric acid (UA). The combination of three active components endows the electrode with large specific surface area, high electrical conductivity, and excellent electrochemical activity. The as-prepared modified electrode exhibited impressive electrocatalytic oxidation performance of DA and UA at an optimum working potential (0.172 V vs. Ag/AgCl for DA and 0.288 V vs. Ag/AgCl for UA) with linear detection range from 1.25 × 10-6 to 2.81 × 10-4 M and 0.75 × 10-6 to 1.66 × 10-4 M and the detection limit of 0.15 and 0.25 μM (S/N = 3) for DA and UA, respectively. Additionally, the peak-to-peak separation signals in DPV are 116 mV. The influence of several possible co-existing substances was investigated. The applicability of the method for real samples analysis was tested by determination of DA and UA in human serums. This new sensor holds great promise for sensitive determination of DA and UA in real application. Graphical abstract.