Synthesis of Hollow SiO2@C Composites and Their Electrochemical Sensing Performance for Quantitative Detection of Nitrite in Food Products

Environmental analysis and food safety control still depend on quick, precise nitrite monitoring. In response, the current work uses a one-step hydrothermal process to create a hollow SiO 2 @C core-shell material, which is then integrated into an electrochemical nitrite sensor. X-ray diffraction, high-resolution transmission electron microscopy, and scanning electron microscopy all confirm the homogeneous carbon coating and hollow structure, creating a strong foundation for charge transfer. The SiO 2 @C-modified electrode maintains linearity between 0.5 and 4650.0 µM and achieves a detection limit of 0.17 µM. Strong operational stability is demonstrated by the high repeatability (RSD = 1.23%) and the retention of 90.66% of the initial signal after 17 days at 4°C. Reliable performance in complex food matrices is confirmed by standard-addition assays in sausage and fermented bean curd, which provide recoveries of 95.53–100.03% and 98.15–99.83%, respectively. These findings establish the hollow SiO 2 @C sensor as a useful, highly sensitive instrument.