Highly sensitive immunochromatographic assay for qualitative and quantitative control of beta-agonist salbutamol and its structural analogs in foods

Abstract

Salbutamol (SAL) is a beta-adrenoreceptor agonist (beta-agonist) and is widely used as a growth promoter in livestock and poultry. Two schemes for the immunochromatographic analysis of SAL using gold nanoparticles as labels have been developed and tested for modes of visual and instrumental detection. The direct analysis scheme was characterized by an instrumental detection limit 0.4 ng/mL, an operating range 0.6–6.8 ng/mL and a visual detection limit of 10.9 ng/mL. The analysis time was 10 min. The indirect labeling scheme (using a combination of native specific antibodies and labeled anti-species antibodies) allowed the five-fold reduction of the limit of visual detection. In the analysis of foods, the indirect scheme was characterized by a visual detection limit 4.0 ng/g for meat products and 3.0 ng/g for milk samples. The analysis time was 15 min. The developed system was characterized by a high level of cross-reactivity with terbutaline (50%) and orciprenaline (10.5%), molecules of which have similar structures to that of SAL. The assay of milk samples may be implemented without pre-treatment or dilution, proving its applicability to on-site control. Its rapidity and simplicity suggest that the proposed immunochromatographic analysis of SAL is an effective tool for the mass screening of foods.