Simultaneous determination of β2-agonists clenbuterol and salbutamol in water and swine feed samples by dual-labeled time-resolved fluoroimmunoassay

Lanthanide ions, the excellent fluorescence markers, have the potential to simplify the performance of multi-analytes analysis. In this work, a powerful time-resolved fluoroimmunoassay (TRFIA) based on dual-labeled format were performed for detecting clenbuterol and salbutamol simultaneously in water and swine feed samples. Europium (Eu3+)-labeled goat anti-mouse IgG and Samarium (Sm3+)-labeled goat anti-rabbit IgG were prepared and used as fluorescent probes. Under optimal conditions, the half maximal inhibition concentration (IC50) and the limit of detection (LOD, IC10) of the TRFIA were 0.263 and 0.007 ng/mL for clenbuterol, and 0.179 and 0.014 ng/mL for salbutamol, respectively. The cross-reactivities of the TRFIA between these two beta(2)-agonists and with their analogues were negligible, thus indicated high specificity and promoted the simultaneous determination. The spiked recoveries were 72.2%-102.2% with relative standard deviations (RSDs) of 3.4-13.8% for clenbuterol and salbutamol in water and swine feed samples. Furthermore, the results of TRFIA correlated well with those obtained by HPLC. The proposed dual -labeled TRFIA was a satisfactory tool for simultaneous, sensitive, efficient and labour-saving detection of clenbuterol and salbutamol in water and swine feed samples. (C) 2016 Elsevier Ltd. All rights reserved.