An ultrasensitive immunochromatographic assay for non-pretreatment monitoring of chloramphenicol in raw milk

Abstract

A non-pretreatment monitoring method based on immunochromatographic test (ICT) strips was developed to test for chloramphenicol (CAP) in raw milk. This assay was designed to measure competitive binding affinities for CAP molecules in raw milk and CAP antigen immobilized on strips with colloidal gold nanoparticles (GNPs, average diameter of 30 nm) labeled with anti-CAP monoclonal antibody (CAP mAb). Several working conditions, including the CAP solvent, different types and concentrations of CAP mAb, coating antigen, and GNP, were optimized for performance. After optimization, the detection process was carried out in 8 min with a visual limit of detection (LOD) of 0.3 ng/mL for qualitative detection and a LOD of 0.064 ng/mL for semi-quantitative detection. No cross-reactivity was detected toward CAP analogs. Based on these results, this simple and ultrasensitive assay could be thoroughly applied in the on-site testing of CAP in raw milk.

Keywords:

• non-pretreatment
• immunochromatographic test strip
• competitive format
• rapid and ultrasensitive

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work is financially supported by the Key Programs from MOST [grant number 2012BAK17B10], [grant number 2012BAD29B05], and grants from Natural Science Foundation of Jiangsu Province, MOF and MOE [grant number CSE11N1310], [grant number 201310128], [grant number 201310135].