A colorimetric/SERS dual-channel sensor based on multifunctional Co3O4@Ag NFs with photocatalytic signal amplification for ultrasensitive detection of diacetyl in food

Diacetyl is a flavoring agent commonly used to enhance food aroma. However, excessive levels can pose health risks, making rapid and sensitive detection crucial for food safety. In this study, multifunctional cobalt oxide tetraoxide@silver nanoflowers (Co₃O₄@Ag NFs) were synthesized to enhance the photocatalytic coloration of diacetyl, enabling a simple and highly sensitive colorimetric/SERS dual-channel sensor. Co₃O₄@Ag NFs serve three key functions: First, Co₃O₄ acts as a photocatalyst, improving catalytic efficiency and detection sensitivity. Second, Ag nanoparticles enhance light scattering and reflection, prolonging light interaction with diacetyl molecules and accelerating the reaction. Third, the strong electromagnetic field generated by Co₃O₄@Ag NFs creates numerous hotspots, making it an effective and highly sensitive SERS substrate. The sensor achieves detection limits of 10 × 10^-6 mol/L for colorimetric detection and 3.0 × 10^-12 mol/L for SERS, providing a simple, rapid, sensitive, and accurate way for diacetyl detection and offering potential for future food safety analysis.