Abstract:

An immunoextraction method based on anti-clenbuterol (CLE) immunomagnetic nanobeads was developed
for the rapid and specific enrichment of CLE in pork. Immunomagnetic nanobeads were prepared by coupling 77.2 μg
of biotinylated antibodies onto 1 mg of nano-magnetic beads that were coated with 23.9 μg of streptavidin. The optimal
adsorption and desorption conditions were 1 g of homogenized pork extracted with 4 mL of 0.15 mol/L HCl solution with
vigorous shaking. Then, 0.25 mg of magnetic nanobeads were added to the extract and incubated 37 ℃ for 10 min on a
shaker (200 r/min). Totally 100 μL of methanol was mixed with the immunomagnetic nanobeads for 5 min to desorb CLE.
The eluate was diluted 10 times with PBS for ELISA determination. The performance of immunomagnetic nanobeads was
evaluated by using CLE-spiked samples. The results indicated that the recovery rate of CLE at spiked levels between 0.25 ng/g
and 2 ng/g were more than 80% with relative standard deviation of 11.9% to 15.7%. However, the recovery rate of CLE was
decreased to 61.2% with relative standard deviation of 7.8% while the spiked concentration was increased to 5 ng/g.

Key words: clenbuterol, enrichment, nanomagnetic bead, pork