Selective detection of riboflavin biomolecule via electroreduction over laser induced graphene-anchored iron nanoparticles using spectroelectrochemistry

Riboflavin (RF) is detected via an in situ spectroelectrochemistry (SEC) technique using the laser induced graphene (LIG)-anchored iron nanoparticles (Fe NPs) modified fluorine tin oxide (FTO) glass electrode. The Fe-dispersed phenol-formaldehyde copolymeric film is converted to Fe-LIG in a single step via laser ablation. Synchronously coupled with cyclic voltammetry, the UV-Vis spectrophotometry is used to measure the electro-reduced RF species, based on the absorbance peak at ∼400 nm wavelength. The Fe-LIG modification of FTO increases the electrochemical surface area of the electrode approximately 3 times, leading to a greater sensitivity and diminished charge transfer resistance necessary for the electrochemical reduction of RF. A linear response of the sensor is observed for the RF concentration ranging from 0.05 - 40 µg/ml, with a low limit of detection of 0.048 µg/ml. The sensor was successfully tested in artificial urine to replicate the real sample analysis. The SEC sensor was also tested in the interferent-laden RF solutions where the unaltered peak intensities in the absorbance spectra were observed, clearly justifying the use of SEC in lieu of the electrochemical or UV-Vis spectrophotometry techniques alone where the convolution, disfigurement, or alteration in peak intensity of the interferents is commonly observed. The findings in this study have paved way for the application of an inexpensive metal-LIG composite-based electrode in conjunction with the SEC approach for the interference-free sensing of critical biomolecules.