Visual Screening and Colorimetric Determination of Clenbuterol and Ractopamine Using Unmodified Gold Nanoparticles as Probe.

In this paper, a sensitive method for the colorimetric detection of clenbuterol and ractopamine using citrate-stabilized gold nanoparticles (AuNPs) as probe was developed. The concentration of clenbuterol and ractopamine could be determined with naked eyes or a UV-vis spectrometer. By optimizing the influence of NaHSO4 and incubation time, clenbuterol could be detected in the linear range of 0.1-4 mu g/mL with the detection limit of 0.0158 mu g/mL, and ractopamine could be detected in the linear range of 1-9 mu g/mL with the detection limit of 0.0229 mu g/mL. The proposed method could be successfully applied to detect clenbuterol and ractopamine in pig urines by a simple pretreatment with excellent recoveries. The proposed colorimetric assay exhibits good reproducibility and accuracy, providing a simple and rapid method for the analysis of clenbuterol and ractopamine.