A tetraphenylethylene-based aggregation-induced emission sensor: Ultrasensitive turn-on fluorescent sensing for phosphate anion in pure water

A new fluorescent sensor of tetraphenylethylene (TPE) derivate with four dimethylformamidine and four chloride anions, sensor 1, was resoundingly synthesized. Meanwhile, the structure of sensor 1 has been characterized by H-1 NMR, C-13 NMR, FT-IR and mass spectrum. Sensor 1 can dissolve in water completely and showed significant fluorescence enhancement response towards PO43- with selectivity and sensitivity in pure water. The results of fluorescence spectra, turbidity measurement, dynamic light scattering (DLS) and fluorescent micrographs elucidated that the distinct fluorescence enhancement of sensor 1 with PO43- anion can be attributed to the aggregation-induced emission (AIE) of TPE. The AIE of sensor 1 with PO43- anion was reversible, proved by the alternate addition of PO43 anion and calcium ion. The fluorescence intensity of sensor 1 at 510 nm gradually increased and was obviously augmented by 266% when the added concentration of PO43- was 150 mu mol L-1 (15 equiv. of sensor 1). In addition, the fluorescence intensity also displayed a good linear relationship with PO43- ions in the large concentration range of 10-150 mu mol L-1 with very low detection limit for PO43- of 6.56 x 10(-8) mol L-1. Furthermore, sensor 1 also presented the semi-quantitative visual detection ability for PO43- in solutions and test paper mode via the fluorescence changes and quantitative detection potential for PO43- in actual water sample.

Automated summary

The newly synthesized sensor 1 can dissolve in water and exhibit significant fluorescence enhancement response towards PO43- with high selectivity and sensitivity.