ABSTRACT
Yttrium vanadate:europium nanoprobes (YVO4∶Eu NPs) with good fluorescence properties and water solubility were synthesized by solvent thermal method.Due to the overlapping of the excitation spectrum of YVO4∶Eu NPs and the absorption spectrum of tryptophan, fluorescent internal filter effect (IFE) occurred, in which YVO4∶Eu NPs were the fluorophore and tryptophan was the absorber, leading the fluorescence of YVO4∶Eu NPs was quenched.Therefore, a new method for the determination of tryptophan was established by using fluorescent YVO4∶Eu as nanoprobes based on IFE.Some experimental parameters, such as the adding amount of YVO4∶Eu NPs, pH value of the reacting solution, and reacting time, were investigated.Under the optimum reaction conditions, the linear range of the method was 4.0×10-6-4.0×104 mol/L and the detection limit was 1.0×10-6 mol/L (3σ).The content of tryptophan in the soy sauce was determined with the recovery of 95.2% and 97.3%.This method is simple, rapid, sensitive and accurate.