Development of a Screening Fluorescence Polarization Immunoassay for the Simultaneous Detection of Fumonisins B₁ and B₂ in Maize

This paper reports the development of a screening fluorescence polarization immunoassay (FPIA) for the simultaneous detection of fumonisins B₁ (FB₁) and B₂ (FB₂) in maize. Three FB₁ tracers including FB₁-fluorescein isothiocyanate isomer I (FB₁-FITC), FB₁-5-([4,6-dichlorotriazine-2-yl]­amino)-fluorescein (FB₁-5-DTAF), and FB₁-Texas Red-X succinimidyl ester (FB₁-TRX) were synthesized and studied to select appropriate tracer–antibody pairs using seven previously produced monoclonal antibodies (mAbs). An FPIA employing the pair of FB₁-FITC and mAb 4B9 showing 98.9% cross-reactivity (CR) toward FB₂ was used to simultaneously detect FB₁ and FB₂. Maize flour samples were extracted with methanol/water (2:3, v/v). After optimization, the FPIA revealed a limit of detection (LOD) of 157.4 μg/kg for FB₁ and an LOD of 290.6 μg/kg for FB₂, respectively. Recoveries were measured for spiked samples of FB₁ or FB₂ separately, ranging from 84.7 to 93.6%, with a coefficient of variation (CV) of <9.9%. Total time needed for FPIA including sample pretreatment was <30 min. The FPIA was used to screen naturally contaminated maize samples. Results detected by FPIA showed good agreement with that of HPLC-MS/MS with a fit of <i>R</i>² = 0.99 for the simultaneous detection of FB₁ and FB₂. The established method offered a rapid, simple, sensitive, and high-throughput screening tool for the detection of fumonisins in maize