Rapid Detection of Aflatoxin M1 by Immunochromatography Combined with Enrichment Based on Immunomagnetic Nanobead

A novel method was developed for detection of aflatoxin M-1 by immunochromatography coupled with enrichment on the basis of immunomagnetic nanobeads. The immunomagnetic nanobeads coated anti-aflatoxin M-1 antibody was synthesized using EDC/NHS method. Immunochromatographic strip was assembled with conjugate pad, sample pad, absorbent pad, and nitrocellulose membrane. Nitrocellulose membrane sprayed with aflatoxin M-1-BSA and donkey anti-mouse antibody served as both test line and control line. For detecting process, immunomagnetic nanobeads were mixed with sample for enriching and separating AFM(1). Afterward enrichment solution was detected by immunochromatographic strip. The limit of detection of this assay for aflatoxin M-1 in raw milk was 0.1 ng mL(-1), which was lower than the legal limit of 0.5 ng mL(-1) set by China. No cross reactions were found with other mycotoxins and common illegal additives. The result by the proposed method was in good agreement with that of ELISA. The assay can be applied for rapid detection of on-site aflatoxin M-1 in raw milk.