Dual-readout immunoassay based on IFE and p-phenylenediamine for detection of zearalenone

In this study, we present a straightforward dual -readout immunoassay for sensitive and specific detection of zearalenone (ZEN) using the inner filter effect (IFE) and p-phenylenediamine (PPD). 2-aminoterephthalic acid (PTA-NH 2 ) is an organic compound that exhibits strong fluorescence at 420 nm. In the presence of horseradish peroxidase (HRP) and hydrogen peroxide (H 2 O 2 ), PPD was oxidized to 2,5-diamino-N, N '-bis(p-aminophenyl)- 1,4-benzoquinone di-imine (PPDox). The fluorescence of PTA-NH 2 was quenched due to the IFE effect, resulting from the effective overlap between the UV -vis absorption spectra of PPDox and the fluorescence spectra of PTANH 2 . Furthermore, PPDox was completely oxidized to p-benzoquinone (PBQ) by sulfuric acid, exhibiting a strong absorption peak at 415 nm and a yellow color. Consequently, a dual -readout immunoassay based on IFE and PPD was developed for the detection of ZEN. The limits of detection for the fluorescent and colorimetric modes were 0.011 ng/mL and 0.019 ng/mL, respectively. The approach can be used to efficiently and accurately detect ZEN in real samples due to the high sensitivity, specificity, and consistency of the dual -readout modes.