A Fluorescence Probe for Tartrazine Detection in Foodstuff Samples Based on Fluorescence Resonance Energy Transfer

In this work, fluorescence resonance energy transfer (FRET) between tartrazine and 3-mercapto-1,2,4-triazole-capped gold nanoclusters (TRO-AuNCs) was investigated and subsequently utilized for the determination of tartrazine (TZ) in foodstuff samples. The TRO-AuNCs which exhibit strong fluorescence emission were synthesized by a simple one-pot procedure. Upon addition of TZ, the fluorescence of TRO-AuNCs could be efficiently quenched, attributing to the FRET between TZ and TRO-AuNCs. Parameters affecting the detection of TZ were investigated including pH, amount of TRO-AuNCs, temperature, and reaction time. Under the optimized experimental conditions, trace amounts of TZ could be determined based on the reduction in the fluorescence intensity of TRO-AuNCs. A linear relationship was established at concentrations ranging from 0.08 to 37.5 μM, and the limit of detection (LOD) at 28 nM was achieved with the method. The proposed method has been successfully applied to the determination of TZ in juice and honey samples purchased from a local supermarket. Excellent recoveries at 92.0∼105.2 % and precision (RSD 1.14∼2.84 %) were attained, respectively, which confirmed the great potential of 3-mercapto-1,2,4-triazole-stabilized gold nanoclusters toward practical measurement of tartrazine in foodstuff samples.