Design and fabrication of self-calibration colorimetric/fluorescence/SERS tri-modal optical sensor for highly rapid and accurate detection of mercury ions in foods.

The improvement of detection accuracy without loss of rapidity and sensitivity by optical sensors in complex food analysis is still full of challenges owing to the matrix interference. Herein, a novel and simple self-calibration colorimetric/fluorescence/surface-enhanced Raman spectroscopy (SERS) tri-modal optical sensor based on aminated Rhodamine 6G (R6G-NH) was developed for highly rapid, sensitive, and accurate detection of Hg in food samples. The high recognition specificity of R6G-NH for Hg can be achieved through the metal chelation interaction between Hg and -NH, -COOH groups in R6G-NH with formation of R6G-NH-Hg-R6G-NH complex. The DFT and FDTD simulations were adopted to confirm the theoretical feasibility in Hg detection by tri-modal optical. Under the optimum conditions, the analytical method based on self-calibration tri-modal optical sensor for Hg detection was established with promising properties (rapidity, linearity, linear range, LOD, and LOQ), providing a strategy in rapid, selective, sensitive, and accurate detection for food safety.