MoS2 quantum dots for on-line fluorescence determination of the food additive allura red

This work presents an on-line fluorescence method for the allura red (AR) determination. The method is based on the fluorescence quenching of dots of MoS2 because of their interaction with the non-fluorescence dye. MoS2-dots were synthetized and characterized by spectroscopic techniques and High Resolution Transmission Electronic Microscopy (HR-TEM). The simultaneous injection of the nanomaterial and the dye in a flow injection analysis system allows the determination of allura red at 1.7 x 10(-6) M concentration level with a very good accuracy and precision (Er minor than 10% and RSD lower than 8%) and a sampling frequency of 180 samples per hour. Moreover, the interaction fluomphore-quencher results a dynamic inhibition mechanism. The proposed methodology was applied to the AR analysis in soft beverages and powders for gelatine preparation. Colourant concentrations of 63 +/- 2 mg/L (n = 3) and 0.30 +/- 0.01 mg/g (n = 3) were found, respectively. These results were validated by high performance liquid chromatography technique.

Automated summary

A novel online fluorescence method using MoS2 dots for the determination of allura red (AR) was developed, showing high accuracy and precision for detecting AR concentration. The method was successfully applied in the analysis of AR in soft beverages and powders for gelatine preparation, with results validated by high performance liquid chromatography technique.