A rapid lateral flow test for the determination of total type B fumonisins in maize

Abstract

A one-step lateral flow test was developed for the quantitative determination of total type B fumonisins in maize with a test range up to 4,000 microg/kg and a limit of detection of 199 microg/kg. The test presented gives a result within 4 min, including 1 min strip drying, and does not require any sample cleanup steps after a previous 3-min sample extraction. Quantitative readout with a compact photometric strip reader will also indicate the best suited measurement range when needed. The test is based on a competitive immunoassay format where a ready-to-use antibody-colloidal gold particle complex is mixed with 50 microL sample extract in a microwell and used as a signal reagent. The test strip is inserted into the well and the mixed content migrates onto the strip, which contains a test zone and a control zone. Mycotoxin-protein conjugate coated on the test zone captures free signal reagent, and colored particles concentrate, forming a visible line. The intensity of the test line is dependent on the total fumonisin concentration in the sample. Naturally contaminated quality-control maize material was used for matrix-matched calibration of photometric readout. The test presented is both quantitative and rapid, with no cross-reactivity to other mycotoxins. The applicability of the lateral flow test was shown by the screening of 23 naturally contaminated maize samples. Relative standard deviations ranged from 1.7 to 32.9%.