Colorimetry /SERS dual-sensor of H₂O₂ constructed via TMB-Fe₃O₄@ AuNPs

Hydrogen peroxide (H₂O₂) detection with high sensitivity plays an important role in biomedical research and food engineering. By combining colorimetry and surface enhanced Raman spectroscopy (SERS), we synthetize a novel H₂O₂ dual-sensor constructed via TMB-Fe₃O₄@AuNPs. In the presence of H₂O₂, the peroxide model enzyme might catalyze the oxidation of 3,3',5,5'- tetramethylbenzidine (TMB) as blue charge transfer complex (CTC) for colorimetry, and then facilitate the sensitivity improvement of SERS detection. The achieved results show that in colorimetry, the linear range is from 40 μM to 5.5 mM with the detection limit of 11.1 μM; in SERS detection, the linear range is from 2 nM to 1 μM with the detection limit of 0.275 nM. Clearly, this mutual reference strategy improves both the detection limit of colorimetry and the sensitivity of SERS detection. Moreover, this colorimetry/SERS dual-sensor constructed via TMB-Fe₃O₄@AuNPs is successfully applied to the H₂O₂ detection in plasma and milk, indicating the excellent performance and flexibility.