<i>Allium macrostemon</i> bunge-like manganese tetroxide composite for sensitive detection of dopamine in human biological samples

A three-dimensional (3D) composite material, which mimics <i>Allium macrostemon</i> bunge-like manganese (Mn) tetroxide (amb-Mn₃O₄), was prepared utilizing a simple one-pot hydrothermal method. The microstructure of Mn₃O₄ was adjusted by the addition of polyethylene glycol 400 (PEG 400). Experimental results showed that the best amb-Mn₃O₄ material for dopamine (DA) detection could be achieved when the volume ratio of PEG 400 to purified water was 1 : 3. The electrochemical sensor developed with this material revealed a good linear relationship with DA concentrations in 2 concentration ranges: 0.0001-0.0156 mmol L^-1 and 0.0196-0.4196 mmol L^-1 measured by chronoamperometry (CA). The sensor possessed a limit of detection (LOD) of 0.028 μmol L^-1 and a sensitivity of 5281.6 µA (mmol L^-1)^-1 cm^-2 towards DA. Furthermore, the sensor was efficient in detecting DA levels from human biological samples such as urine and serum, which is an optimal strategy for the advancement of highly efficient "electrochemical sensors" for DA analysis.