Smartphone-integrated colorimetric nanosensor for azodicarbonamide detection in flour using BSA/MnO₂ nanoprobes

A smartphone-integrated colorimetric sensing platform based on bovine serum albumin (BSA)-templated manganese dioxide (BSA/MnO₂) nanoprobe was successfully constructed to achieve high sensitivity and high selectivity for the detection of azodicarbonamide (ADA) in flour. The BSA/MnO₂ nanoprobe was synthesized by a simple one-pot reduction method of BSA using KMnO₄, without the need for complex post-processing, and had excellent water dispersibility. It undergoes redox reactions with glutathione (GSH) causing self-degradation. Since ADA can oxidize the thiol groups of GSH to disulfide bonds, thereby reducing GSH-mediated MnO₂ degradation, this property was cleverly used for the quantitative detection of ADA. By combining the colorimetric nanoprobe system with smartphone RGB analysis technology, we successfully developed a portable detection platform for accurate determination of ADA content in flour. This research not only provides a simple and practical nanoprobe detection solution for food safety monitoring, but also promotes the innovative application of smartphone-assisted detection technology in the field of food contaminant analysis.