ABSTRACT
A fluorescent polymer dots positive readout and sensitive lateral flow assay (LFA) based on fluorescent quenching has been developed to detect ractopamine (Rac), a chemical residue in food, harmful to human health. Compared with traditional LFA strips, these fluorescent quenching LFA (FQLFA) strips provide a positive correlation method that allows users to obtain results from a weak fluorescent signal. The immunoassay strip scheme is based on the fact that fluorescent polymer dots (FPDs) in close proximity to gold nanoparticles (AuNPs) represent a strong fluorescent quenching. We show that the FQLFA strips can be used as a source to quantitatively analyze Rac in phosphate buffers (PB), swine urine and muscle tissue samples. The lowest detection limitation of the FQLFA was 0.16 ng mL(-1). Our results indicated that this novel scheme was more suitable for rapid detection of small molecules.
