Development of a quantum dot-based immunochromatography test strip for rapid screening of oxytetracycline and 4-epi-oxytetracycline in edible animal tissues

ABSTRACT

A rapid and sensitive immunochromatographic test strip (ICTS) was developed in a competitive format with the quantum dot-conjugated monoclonal antibody specifically to determine the residues of oxytetracycline (OTC) and its metabolite 4-epi-oxytetracycline (4-epi-OTC). Using an ICTS reader, the 50% inhibition concentration (IC₅₀) was found to be 3.41 ± 0.29 ng ml^–1 of OTC in phosphate-buffered saline samples and the detection limit was 0.44 ± 0.05 ng ml^–1. The visual cut-off level of the ICTS is 25 ng ml^–1. The recoveries from tissue samples spiked with OTC of 50–600 μg kg^–1 were 74.2–107.2%, with coefficients of variation below 15%. The method was used to analyse incurred tissue samples, and there was good correlation (R² = 0.999) between the ICTS and high-performance liquid chromatography. These results indicate that ICTS is suitable for the rapid and quantitative detection of OTC and 4-epi-OTC residues in edible animal tissues.

KEYWORDS:

• Oxytetracycline
• immunochromatography test strip (ICTS)
• quantum dot
• quantitative detection

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors would like to thank the Scientific and Technological Research Project of Chongqing China (Project No. cstc2016shmszx80069); China Scholarship Council (CSC No. 201608505051) and the National Natural Science Foundation of China (Project No. 31671939); Natural Science Foundation of Chongqing (Project No. cstc2014jcyjA10063).