Colorimetric Detection of Hydrogen Peroxide and Glutathione Based on Peroxidase Mimetic Activity of Fe3O4-sodium Lignosulfonate Nanoparticles

The sodium lignosulfonate (SL) modified Fe 3 O 4 (Fe 3 O 4 -SL) nanoparticles with excellent peroxidase-like activity were prepared by one-step solvothermal method, which were applied to sensing hydrogen peroxide (H 2 O 2 ) and glutathione (GSH) with color change. Firstly, the morphology and composition of Fe 3 O 4 -SL nanoparticles were characterized. The results showed that the synthesized Fe 3 O 4 -SL nanoparticles had a spherical structure with an average diameter of 220 nm. Subsequently, the peroxidase-like activity of Fe 3 O 4 -SL nanoparticles was investigated by catalyzing the formation of blue-colored oxidized TMB (ox-TMB) by 3,3’,5,5’-tetramethylbenzidine (TMB) in the presence of H 2 O 2 . Mechanism studies showed that the Fe 3 O 4 -SL nanoparticles exhibited better catalytic activity than natural horseradish peroxidase (HRP), and the catalytic pathway abode by the ping-pong mechanism. Finally, the colorimetric sensor for H 2 O 2 was established, which had a linear range of 0.5–150 μmol/L, a detection limit of 0.139 μmol/L and good selectivity. In addition, according to the decolorization reaction of ox-TMB and GSH and the scavenging effect of GSH on hydroxyl radicals, a colorimetric GSH sensor was further constructed. Based on the above results, a colorimetric detection platform for GSH was built, by which a detection range of 0.5–25 μmol/L and a detection limit of 0.08 μmol/L were obtained. The results above showed that the colorimetric sensing system constructed here had a wide detection range, good selectivity and stability for detection of GSH, which would provide an important reference in food monitoring, biomolecule detection and other fields.