A facile fabrication of ratiometric electrochemical sensor for sensitive detection of riboflavin based on hierarchical porous biochar derived from KOH-activated Soulangeana sepals.

Herein, a facile ratiometric electrochemical method was developed for sensitive sensing of riboflavin (RF) based on hierarchical porous biochar (HPB) modified electrode. In this sensing system, the reference paracetamol (PA) was directly added into electrolyte solution without the requirement of complex immobilization process. HPB derived from KOH-activated Soulangeana sepals displays hierarchical porous structure, high specific surface area and rich oxygen-containing functional groups, which is favorable for RF adsorption and enrichment. Besides, the excellent electronic conductivity and superior electrocatalytic activity of HPB can effectively promote the electrooxidation of RF. Moreover, the dual-signal strategy greatly improves the reproducibility and reliability of electrochemical detection. Based on the proposed ratiometric sensing platform, the sensor exhibits a wider linear range of 0.0007-10M and a lower limit of detection of 0.2 nM. The method also presents good selectivity and has been applied to the determination of RF in milk samples with satisfactory results.