Rapid Determination of Ractopamine Residues in Edible Animal Products by Enzyme-Linked Immunosorbent Assay: Development and Investigation of Matrix Effects

Abstract EN

To determine ractopamine residues in animal food products (chicken muscle, pettitoes, pig muscle, and pig liver), we established a rapid direct competitive enzyme-linked immunosorbent assay (ELISA) using a polyclonal antibody generated from ractopamine-linker-BSA.

The antibody showed high sensitivity and specificity in phosphate buffer, with an IC50 of 0.6 ng/mL, and the limit of detection was 0.04 ng/mL.

The matrix effect of the samples was easily eliminated by one-step extraction with PBS, without any organic solution or clean-up procedure such as SPE or liquid-liquid extraction, making it a much more simple and rapid method than previously reported ones.

The detection limit in blank samples was 0.2 μg/kg.

To validate this new RAC (ractopamine hydrochloride) ELISA, a RAC-free pig liver sample spiked at three different concentrations was prepared and analyzed by HPLC and ELISA.

The results showed a good correlation between the data of ELISA and HPLC (R2>0.95), which proves that the established ELISA is accurate enough to quantify the residue of RAC in the animal derived foods.