Ultra-lowly detect dopamine via multi-step calcination of mangosteen-derived biomass carbon

Abnormal concentration of Dopamine (DA), a vital neurotransmitter in the nervous system, implicates the pathogenesis of various neurological disorders. However, detection of low concentrations of DA in biological samples still faces great challenge. In this work, an electrochemical DA sensor with ultra-low detection limit was innovated with mangosteen biomass carbon (MBC). Different calcination processes were applied to treat MBC, among which a unique multi-step calcination was used to sequentially heat MBC to 200 °C, 300 °C, 400 °C, and 900 °C, resulting in a unique porous 3D honeycomb structure, a large surface area, and abundant active sites. The multi-step calcinated biocarbon-based sensor offers the high sensitivity of 308 μA·μM −1 ·cm −2 , wide detection range of 0.01–300 μM, and the lowest detection limit of 2.8 nM among the best of biomass carbon-based DA sensors. This work reveals that a delicately designed calcination process plays a critical role in the electrocatalytic performance of biomass carbon. It also demonstrates that the MBC sensor is applicable for the actual detection of human serum samples, with recovery rates of 97.0 %–103.9 %, showing significant potential in biomedical applications.