A multispectral and LC-MS/MS approach for investigating matrix interference in aflatoxin B1 analysis of pressed peanut cake.

Pressed peanut cake (PPC) is a valuable plant-based protein source, but its complex matrix might lead to underestimation of aflatoxin B1 (AFB1). This study established a multi-technique diagnostic framework integrating UV-Vis, FTIR, LC-MS/MS, and SEM to systematically dissect matrix interference in different extraction solvents, ultimately correlating with AFB1 detection. It was found that, due to lipid interference, the use of nonpolar solvents during extraction not only significantly amplified detection errors but also severely compromised extraction efficiency, resulting in an analytical error exceeding 85%. Systematic profiling revealed that conventional methanol/water extraction introduced dual errors, attributable to either inefficient toxin extraction or excessive pigment co-extraction, leading to an AFB1 underestimation up to 50%. Acetonitrile/water was identified as the optimal extraction solvent, minimizing interferents and achieving consistent AFB1 recoveries >90%. This work not only provides a practically applicable detection protocol but also offers a clear mechanistic explanation for the observed errors.