Sensitive and multiplexed analysis of aflatoxins using time-of-flight secondary ion mass spectrometry

A rapid and reliable analysis of toxins is prerequisite for food control and human healthcare. Here we demonstrate a simple and multiplexed assay of aflatoxins using time-of-flight secondary ion mass spectrometry (TOF-SIMS). By simply adsorbing either a single analyte or mixed ones onto a gold substrate, the corresponding secondary molecular ions([M+H]+) were clearly observed in a single mass spectrum. As a result of concentration-dependent peak intensity, quantitative and multiplexed analysis of different aflatoxin analogs from corns was accomplished with immunoaffinity column and TOF-SIMS analysis, which showed a good correlation with HPLC data. The detection sensitivity was estimated to be as low as 10 ng mL−1. This approach presented here will find a wide application to detection of low-levels of toxins in a rapid and multiplexed way.