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 (Co 3 O 4 @Ag NFs) were synthesized to enhance the photocatalytic coloration of diacetyl, enabling a simple and highly sensitive colorimetric/SERS dual-channel sensor. Co 3 O 4 @Ag NFs serve three key functions: First, Co 3 O 4 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 Co 3 O 4 @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. • Diacetyl can catalyze the production of oxT-MB from TMB under light. • Co 3 O 4 @Ag NFs can serve as photocatalyst to promote the catalytic reaction. • Co 3 O 4 @Ag NFs can be efficient SERS substrate to enhance Raman signal of ox-TMB. • The detection limits were 10 μM for colorimetry and 3.0 × 10 −12 M for SERS. • This dual-channel method provides new idea for the detection of diacetyl in food.