A novel dopamine sensor based on Mo doped reduced graphene oxide/polyimide composite membrane

•A novel Mo-rGO/PI film sensor was firstly prepared with a new method.•There is almost no report so far that MoO2 can catalyze DA.•The Mo-rGO/PI film sensor of DA shows a wide linear range (0.1–2000 μM).•Ascorbic acid and uric acid did not interfere with the DA detection.•The prepared sensor exhibits long-term stability and good reproducibility.

A novel Mo doped reduced graphene oxide/polyimide (Mo-rGO/PI) composite membrane sensor for dopamine (DA) has been successfully prepared by a simple and effective method. In this work, the rGO was doped into PI to prepare polymer composite membrane. Although rGO has a certain degree of catalytic activity for DA, more important is Mo doped rGO/PI film can enhance its electrocatalytic activity towards the oxidation of DA, and so far there is almost no report that MoO2 can catalyze DA. In order to find the best film, different doped ratios of Mo powder are further investigated, and the combined characterization by X-ray photoelectron spectra and energy-dispersive X-ray spectroscopy indicate that Mo exist in rGO/PI film in the form of MoO2. Under optimal conditions, the Mo doped rGO/PI film exhibits excellent catalytic activity to DA, with a linear response throughout the concentration range from 0.1 to 2000 μM, it also shows long-term stability and good reproducibility, and performs well for detection of DA in human blood serums and injection. These results suggest that the novel Mo-rGO/PI film is a promising candidate for the accurate and reliable detection of DA signals in biological samples.

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