Lateral flow immunoassay (LFIA) is considered as a suitable diagnostic tool for the detection of mycotoxins such as ochratoxin A. In most cases, gold nanoparticles (G or Au), due to high stability, easy synthesis and easy result reading (detection with naked eyes), are used in these evaluations. In this project two labels including gold nanoparticles and fluorescent europium (III) [Eu(III)] nanoparticles (Eu) were used for OTA monoclonal antibody (OTA-mAb) conjugation. In the LFIA using Au labels the test strip was composed of four parts: a sample pad, conjugate pad, nitrocellulose membrane and an absorbent pad. Results were obtained within 15 min, and in addition to visual examination, they were read by the rapid color intensity portable strip reader. The visual and computational detection limits (vLOD and cLOD, respectively) for ochratoxin A were 0.2 and 0.25 ng mL -1 , respectively. In the assay using Eu the test strip was composed of three parts: a sample pad, nitrocellulose membrane and an absorbent pad. The results were obtained in 8 min and in addition to observation under UV light, read by a portable strip reader. The established method allows quantitative determination of OTA with limit of detection as low as 0.05 ng mL -1 in the samples. For validation, spiked samples including wheat, maize, soybean and rice were respectively assayed by two LFIA formats and a standard high performance liquid chromatography equipped with a fluorescence detector (HPLC-FLD), and good agreement of results was obtained between two methods. Keywords: Lateral flow immunoassay (LFIA); Ochratoxin A; Agro-products; Gold nanoparticles, Eu (III) nanoparticles
