Determination Research On Nitrofuran Antibiotics And Their Metabolites Residues In Animal Foods Type

In this study, the detections of nitrofuran residues were analyzed by developing the assay for metabolites of nitrofuran. 3-amino-2-oxazolidinone (AOZ), the metabolite of furazolidone, and immunogens for the metabolites of furazolidone, nitrofurantoin and nitrofurazone were synthesized in order to prepare homologous polyclonal antibodies. An indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) for detecting 1-aminohydantoin (AHD) in swine tissues and a rapid immunochromatographic assay for semicarbazide (SEM) were developed and validated.Firstly, AOZ was synthesized and characterized by GC-MS and UV. And then, CPAOZ, CPSEM and CPAHD were derived from AOZ, SEM and AHD with 4-Formylbenzoic acid and applied in synthesis of immunogens. The antibodies were acquired by immunizing six New Zealand white rabbits for four months, and after purified the decent titer of antibodies were determined, 153600, 307200 and 614400 for each group.Secondly, an optimal ic-ELISA for detecting AHD in swine tissues was developed by optimizing many factors of the assay and validated in sensitivity, specificity and accuracy. The IC50 for PAHD was 3.6 ng/mL, LOD was 0.085 ng/mL and high specificity for PAHD was obtained without cross-reactivity to various nitrofuran metabolites and veterinary drugs. The swine specimens spiked with AHD were detected by instrumental analysis after derivatization for recovery.Thirdly, a rapid immunochromatographic assay was developed and validated for detecting SEM. Colloidal gold-labeled polyclonal antibody specific to SEM derivative was used as the marker; based on the competitive reactivity theory, the analyte PSEM would compete with CPSEM conjugated ovalbumin. The test strip could efficaciously detect PSEM with a visual detection limit of 40 ng/mL and high specificity. The reliability of the assay was confirmed by testing 80 standard samples in comparison with ELISA. The qualitative detection was accomplished in less than 15 min with low cost, especially for requirements of rapid and simple screening.The paper presented the development and confirmation of an ic-ELISA for detection AHD in swine tissues, which provided a sensitive and fast method for monitoring residues of nitrofurantoin. Our immunochromatographic assay provided an exploratory development for detection of nitrofuran residues, which would be reformed and applied in a widespread range.