Abstract: Aim: This study aimed to develop an enzyme-linked immunosorbent assay (ELISA) method for detecting the residues of furazolidone (FZD) in animal food. Method: The indirect competitive ELISA method based on single chain fragment antibody was established. Result: The optimal antigen mass concentration was 2 μg/mL, and the optimal antibody dilution ratio was 1:500, and the optimal reaction time of primary antibody, the optimal reaction time of secondary antibody and the optimal reaction time of TMB were 60 min, 45 min, and 20 min, respectively. The good linearity was seen in the range of 10-100 ng/mL of FZD, with the IC50 value being 13.01 ng/mL, and the lowest detection limit (LOD) being 1.28 ng/mL, and the recovery rates being 73.38%-84.52%. Conclusion: Compared with the monoclonal antibody against FZD, the detection kit based on single chain fragment antibody displayed wider detection range, higher sensitivity, better specificity and detection stability.

Key words: furazolidone, single chain fragment antibody, enzyme-linked immunosorbent assay