An anti-BSA antibody-based immunochromatographic assay for chloramphenicol and aflatoxin M₁ by using carboxy-modified...

A lateral-flow immunochromatographic assay with excellent sensitivity and wide application potential is described. The bovine serum albumin (BSA) antibody was immobilized in the test line for universality, and preincubation was introduced for high method sensitivity. Carboxy-modified CdSe/ZnS core-shell nanoparticles were used as label, and the fluorescence peaking at 605 nm was detected. The fluorescence in the test line was negative against the relevant analyte content. The chloramphenicol (CAP) and the aflatoxin M₁ (AFM₁) in milk were detected using the same strip to validate the universality. After optimization, the detection limit for CAP is 10 pg·mL^-1, which is three times less that of a conventional assay (30 pg·mL^-1). The detection limit for AFM₁ was 6 pg·mL^-1, which was 13 times less than that of a conventional assay (8 pg·mL^-1). The method was applied in the analysis of spiked milk samples. The performance was compared with that of the commercial ELISA kit, and good agreement was observed. Graphical abstractSchematic representation of the universal and sensitive combined immunochromatographic assay (USICA) and conventional immunochromatographic assay (TICA) of chloramphenicol (CAP) and aflatoxin M₁.