Colorimetric method for clenbuterol detection based on the enzyme-like activity of magnetic Fe3O4@mSiO2@MMT-SDS nanoparticles

This study demonstrates a novel colorimetric method for clenbuterol (CLB) detection based on the peroxidase-like activity of SiO2-coated Fe3O4 nanoparticles (Fe3O4@mSiO2) modified with montmorillonite (MMT) and sodium dodecyl sulfate (SDS), namely, Fe3O4@mSiO2@MMT-SDS. Fe3O4@mSiO2@MMT-SDS nanoparticles were prepared by modifying Fe3O4@mSiO2 with MMT and SDS to impart negative charges to the particle surfaces. The structural properties, steady-state kinetics, catalytic performance, and reaction conditions of the as-prepared nanoparticles were analyzed. Fe3O4@mSiO2@MMT-SDS nanoparticles exhibited excellent dispersion and enzyme-like activity, which improved the affinity with substrate (TMB and H2O2) for the catalytic oxidation of CLB by H2O2, turning the solution blue in the presence of the 3,3ʹ, 5,5ʹ-tetramethylbenzidine chromogen. Under optimal reaction conditions, a strong linear correlation between the absorbance of solution and CLB concentration (R2 = 0.9983) was observed. Here, the limit of detection, spike recovery, and relative standard deviation were 9.6 × 10-9 mol·L-1, 94.2 %–102.2 %, and 2.2 %–4.4 %, respectively. The proposed method is a simple, fast, cost-efficient, and sensitive assay, which can be used to rapidly and accurately screen CLB in pork and animal feeds.