Surface Plasmon Resonance Sensor Based on Mn₂O₃/Au Structure for Detecting Monosodium Glutamate

Monosodium glutamate (MSG) is a commonly used seasoning in various culinary applications. However, excessive intake of monosodium glutamate can cause irreversible harm to the human body. Therefore, the detection of monosodium glutamate in food safety cannot be ignored. In this paper, a fast label-free monosodium glutamate sensor based on surface plasmon resonance (SPR) is proposed. Mn₂O₃ is grown on the surface of a gold film using Mn₂O₃/Au as the medium. The detection results found that with the increase of monosodium glutamate concentration, the resonance wave will have an obvious redshift, and the sensitivity can reach 461.71 nm/%. Within the concentration range of 0–25%, the linear fitting between resonance wavelength and refractive index is greater than 0.99, which ensures the detection resolution. The sensor shown in this paper has great potential and prospects in monosodium glutamate detection and food safety with its excellent sensing performance, simple structure, and economic and environmentally friendly detection method.