Photo-electrochemical detection of dopamine in human urine and calf serum based on MIL-101 (Cr)/carbon black.

Abstract

A new photo-electrochemical sensor based on MIL-101(Cr) MOF/carbon black (CB) is fabricated and characterized. By using differential pulse voltammetry, dopamine (DA) can be effectively detected using aphoto-electrochemical MIL-101(Cr)/CB sensor under visible light. The CB acts as the electron bridge to combine with the large specific surface area and photo-catalytic feature of MOF, which contribute to the improvements of sensitivity of DA detection. The concentration of the catalyst, pH value, accumulation potential, and accumulation time werealso optimized. Furthermore, the electrochemical performances of MIL-101(Cr)/CB sensor was investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scan rate, electrochemically active surface area (ECSA), and amperometric responses. Adetection limit of 0.38nM (LOD = 3 sb/S, sb = 0.028) and aworking range of 1nM to 2.22μM has beenachieved. TheMIL-101(Cr)/CB sensor exhibits excellent reproducibility, stability, and selectivity and also has satisfactory recovery rate for the analysis of real samples including calf serum and human urine. Graphical abstract.