For on-site detection: Portable sensor integrating a bimetallic organic framework-based ternary composite for efficient detection of residual HCHO in aquatic products

Developed a portable HCHO gas sensor for on-site detection. • Using MOF-derived strategy synthesize g-C 3 N 4 /Fe 2 O 3 /NiO ternary composite material. • The sensor exhibits excellent selectivity, repeatability, and stability. • The sensor successfully applied to the detection of residual HCHO in fresh shrimp. Formaldehyde (HCHO) is class 1 carcinogen. In the food supply chain, some vendors illegally use formalin (HCHO aqueous solution) to soak food products in order to extend their shelf life. Eating this food can increase the risk of developing malignant diseases such as leukemia and breast cancer. Therefore, it is crucial to develop portable sensors with high sensitivity, selectivity, and stability for HCHO detection. In this study, Fe/Ni-BTC derived Fe 2 O 3 /NiO nanoparticles are grown in situ on g-C 3 N 4 nanosheets, forming a unique g-C 3 N 4 /Fe 2 O 3 /NiO ternary composite. Gas-sensing test results indicate that the g-C 3 N 4 /Fe 2 O 3 /NiO sensor exhibits excellent gas-sensing performance at 240 °C to 50 ppm HCHO, including superior selectivity, high response (44.95), low theoretical detection limit (50.1 ppb) and long-term stability (60 days). We have further developed a portable HCHO detection system that has been successfully applied to detect residual HCHO in simulated aquatic products (fresh shrimp). This provides an effective monitoring approach to counteract the illegal use of HCHO for preventing food spoilage. It holds broad application prospects in the fields of environmental monitoring and food safety. Download: Download high-res image (162KB) Download: Download full-size image