Highly sensitive detection of melamine based on fluorescence resonance energy transfer between rhodamine B and gold nanoparticles

A rapid, convenient and highly sensitive method for melamine detection was presented based on fluorescence resonance energy transfer between rhodamine B and citrate-stabilized gold nanoparticles . Rhodamine B could be electrostatically adsorbed to the surface of gold nanoparticles and the fluorescence emission of rhodamine B was quenched. Upon addition of melamine, the decreased fluorescence emission recovered, since melamine could induce the aggregation of gold nanoparticles and release the adsorbed rhodamine B. Under the optimal conditions, the fluorescence recovery efficiency was linearly proportional to melamine concentration in the range of 5–1000 μg L −1 . The detection limit was 0.18 μg L −1 , which was greatly lower than the safety limits required in China. The method was successfully applied for melamine detection in milk and powdered infant formula. Many advantages were exhibited by the system such as facile material synthesis, ease of operation, rapid analysis and competitive analytical performance.