Highly Sensitive Detection of Amaranth Realized with Upconversion Nanoparticles-Based Solid Sensor

High performance of synthetic colorants detection system has great importance for food safety, yet its quantitative analysis with high sensitivity remains challenging. Herein, core-shell upconversion nanoparticles based solid sensor (UCNPs-SS) is designed and explored, where the detection limit of 0.01 μg mL-1 can be achieved thanks to the effective energy transfer between amaranth and this fluorescence-based sensor. In addition, this core-shell UCNPs-SS was successfully employed for the amaranth detection of three commercial soft drinks. These positive results indicating that this proposed fluorescence method not only exhibits excellent sensitivity, but also provides feasibility for practical applications.