In this paper, a new monoclonal antibody (Mab) against sulfamethoxypyridazine (SMP) was produced, and a fluorescence polarization immunoassay (FPIA) based on the produced Mab was developed and optimized for the qualitative screening analysis of SMP. The Mab was raised from mice immunized with SMP linked to bovine serum albumin (BSA) by carbodiimide activated ester formation, using a succinic anhydride spacer molecule between SMP and BSA. Fluorescein labeled sulfachloropyridazine (SCP) and SMP (tracer) were synthesized and purified by thin layer chromatography (TLC). The developed screening FPIA method can tolerate up to 20% methanol, and satisfactory assay sensitivity can be obtained between pH 4 and pH 8 and at lower salt concentration. The anti-SMP Mab exhibited a high cross-reactivity with SCP. The effect of the tracer structure on the analytical characteristic of the determination and on antigen-antibody binding constants was studied. The limits of detection (LOD) were 0.7 ng/mL for SMP and 0.25 ng/mL for SCP in buffer, respectively, whereas negligible cross-reactivities were exhibited by related sulfonamides. Analysis of SMP and SCP-fortified milk samples by the FPIA showed average recoveries from 60 to 145%.

No abstract

Summary A fluorescence polarisation immunoassay (FPIA) for the screening of sulphamethazine (SMZ) in chicken muscle was developed. Fluorescein‐labelled tracers for several sulphonamides were synthesised and monoclonal antibodies (Mabs) and polyclonal antibody (Pab) were produced. The Mabs and Pabs were raised against sulphonamides conjugated to bovine serum albumin by a diazo method. The most sensitive FPIA method for SMZ detection was based on a combination of the Mab against SMZ–bovine serum albumin and tracer SMZ labelled with fluorescein isothiocyanate. The limit of detection and IC50 for SMZ were 1 and 16 ng mL−1. Recoveries of SMZ from fortified chicken muscle samples averaged between 78% and 89%. The proposed FPIA method was applied for determining SMZ in an actual residue study.

No abstract