Determination of 3.5-dinitro-N’-(5-nitrofurfurylidene) salicylic acid hydrazide in fish using immunochromatographic strip tests

The nitrofurans were recently banned from use in livestock production due to their potential carcinogenicity in humans. Therefore, the screening of foods from animal origins for nitrofurans became mandatory. A rapid, specific and sensitive method based on immunochromatographic strip test has been developed for the determination of 3.5-dinitro-N’-(5-nitrofurfurylidene) salicylic acid hydrazide (DNSH) residues in fish. Fish samples were prepared by ultrasonic bath extraction, centrifugation, filtration, drying and res-suspension. The antigen (DNSH-glutaraldehyde-ovalbumin) and a goat anti-mouse IgG antibody were drawn onto a nitrocellulose membrane as the test and control line, respectively. Under optimal conditions, the DNSH cut-off limits for the test strips were determined as 10 ng/mL in 0.01 M phosphate buffered saline and 25 ng/mL in fish samples, with results obtained within 5min. Our data suggests this immunochromatographic assay can be used for the sensitive, rapid, and specific on-site screening of DNSH in fish products.