Enhanced sensitivity in tanshinol detection using manganese dioxide-doped laser-induced graphene sensor

Tanshinol (3-(3,4-dihydroxyphenyl)-2-hydroxypropanoic acid), the primary active constituent of Salvia miltiorrhiza, is a well-known compound in traditional Chinese medicine. Precise determination of tanshinol concentration is imperative for evaluating its therapeutic efficacy in treating cardiovascular diseases and tumors. This study presents an innovative electrochemical sensor based on manganese dioxide (MnO₂)-doped laser-induced graphene (LIG) for the highly sensitive detection of tanshinol. The novel approach results in LIG that adheres tightly to the substrate, with uniformly grown MnO₂ nanoparticles significantly enhancing the specific surface area and facilitating mass transfer. The MnO₂ exhibits excellent electrochemical activity and high conductivity, effectively catalyzing the redox reactions of tanshinol. Under optimal conditions, the sensor demonstrates a linear detection range from 1 to 320 μM and a detection limit of 29.6 nM. The sensitivity reached 11.33 μA μM⁻¹ cm⁻² (1–80 μM) and 1.19 μA μM⁻¹ cm⁻² (80–320 μM), which is significantly better than existing sensors. Successful application in the analysis of real samples confirms its reliability and accuracy, comparable to standard methods. The MnO₂/LIG electrode not only improves the electrical properties of graphene but also makes a significant contribution to the field of traditional Chinese medicine (TCM) detection, providing a novel method for monitoring medicinal compounds.