Phenanthridine based fluorescent probe for Th4+ ion chemosensor

• A new piperazine-based phenanthridine sensor probe was synthesized and characterized. • The fluorescence revealed that 5a is a superior selective sensor towards Th 4+ ion in the presence of other competitive metal cations. • The kinetic study realized the detection of Th 4+ ions in 15 s. • The limit of detection value is as low as 2.76 nM for Th 4+ ion. • Probe 5a has been investigated for test paper strips applications as well as Th 4+ ion analysis in real water samples. A benzhydrylpiperazine-based phenanthridine ( 5a ) moiety has been developed as a ratiometric fluorescence and colorimetric probe for the detection of Th 4+ ion. After the addition of Th 4+ ion, probe 5a was immediately color-altered from blue to yellow fluorescence with an emission maximum at 560 nm. Probe 5a showed superior selectivity and sensitivity towards Th 4+ ions over the other competitive metal ions. This sensor probe exhibited a lower detection limit (2.76 nM). Then through the 1 H NMR titration experiment, it was confirmed that the benzhydrylpiperazine moiety of 5a was chelated with Th 4+ ion. However, probe 5a was utilized for the detection of Th 4+ ion in real water samples and monazite sand. Most importantly, the application of this sensor probe 5a for the recognition of Th 4+ ion in E. coli cells had been successful.