Bio-nanoparticles sensor couple with smartphone digital image colorimetry and dispersive liquid–liquid microextraction for aflatoxin B1 detection

A novel nanobiosensor-based colorimetric method was developed by integrating ZnO nanoparticles functionalized with curcumin, dispersive liquid-liquid microextraction (DLLME), and smartphone digital image colorimetry for the sensitive detection of aflatoxin B1 (AFB1) in baby food samples. The unique combination of biologically-derived ZnO nanoparticles with curcumin created a sensing platform, while DLLME provided efficient pre-concentration of the target analyte. A custom-designed portable colorimetric box enabled standardized image capture and analysis using a smartphone camera and colorimetric software. Under optimized conditions using chloroform as the extraction solvent and acetonitrile as the disperser solvent, the method achieved a remarkable limit of detection of 0.09 μg/kg within linear concentration range of 0-1 μg/L. The calibration curves demonstrated excellent linearity (R² > 0.9906) with high precision (RSD < 5.52%). The method was successfully validated using baby food samples, achieving high recoveries (89.8-94.2%). This innovative integration of nanobiosensing, microextraction, and smartphone technology offers a rapid, highly sensitive, and cost-effective platform for on-site AFB1 detection in food safety applications, particularly beneficial for resource-limited settings.