Glassy carbon electrode modified with Nafion–Au colloids for clenbuterol electroanalysis

Stable Nafion–Au colloids were immobilized on a glassy carbon electrode (GCE) for detection of β-agonist clenbuterol by electroanalysis. The Au colloids were prepared by a one-step electrodeposition onto GCE, with obvious electrocatalytic activity present. The negatively charged Nafion film was an efficient barrier to negatively charged interfering compounds, resulting in accumulation of positively charged clenbuterol at the Nafion film. The electrochemical characters of the electrode during various modified steps in a redox probe system of K4[Fe(CN)6]/K3[Fe(CN)6] were confirmed by cyclic voltammetry (CV) and AC-impedance. In Britton–Robinson (B–R) buffer solution (pH = 2.0) and the potential range of −0.2 to 1.2 V, the Nafion–Au colloid modified electrode, compared to a bare GCE, exhibits obvious electrocatalytic activity towards the redox of clenbuterol by greatly enhancing the peak current with a linear calibration curve from 8.0 × 10−7 to 1.0 × 10−5 mol/L and a detection limit of (1.0 × 10−7 mol/L) (R = 0.996). The modified electrode shows high sensitivity, selectivity and reproducibility. The recovery for detecting clenbuterol (∼10−6 mol/L) in human serum is up to 98.19%.