Direct competitive enzyme-linked immunosorbent assay for sulfamethazine

Area of Science:

• Food safety analysis
• Veterinary drug residue detection
• Analytical chemistry

Background:

• Sulfamethazine (SMZ) is a common veterinary antibiotic.
• Accurate detection of SMZ in food products like pork is crucial for public health.
• Existing detection methods may require optimization for routine screening.

Purpose of the Study:

• To develop and validate a direct competitive enzyme-linked immunosorbent assay (ELISA) for screening sulfamethazine (SMZ) in pork tissues.
• To compare the performance of the homemade ELISA with commercial ELISA and High-Performance Liquid Chromatography (HPLC).

Main Methods:

• Development of a direct competitive ELISA using affinity-purified polyclonal antibody-coated microtiter plates.
• Extraction of SMZ from fortified pork tissues using octadecyl silica (C18) and dichloromethane.
• Measurement of extracted SMZ using homemade ELISA, commercial ELISA, and HPLC.

Main Results:

• The homemade ELISA demonstrated high correlation with HPLC (r=0.993, p<0.01).
• The assay showed sensitivity for SMZ detection at the maximum residue level (MRL), comparable to commercial kits.
• Stability tests at 40°C for 14 days showed no significant impact on assay sensitivity.
• A detection limit of 10 ng/g for SMZ in pork tissues was achieved.

Conclusions:

• A reliable and sensitive homemade ELISA for screening SMZ in pork tissues has been successfully developed.
• The developed ELISA is suitable for routine screening of SMZ residues in pork.
• This assay contributes to ensuring the safety of pork products by detecting antibiotic residues.