Fluorometric determination of Fe3+ and polychlorinated benzenes based on Tb3+-pyromellitic acid coordination polymer

A luminescent Tb 3+ -pyromellitic acid (H 4 L   =   pyromellitic acid) coordination polymer (Tb-H 4 L CP, TbL 0.5 (H 2 L) 0.5 (H 2 O)·DMF) was prepared for multiresponsive fluorescence sensor. The Tb-H 4 L CP exhibits uniform nanospheres with average diameter of 220   ±   20   nm, good crystalline structure, and good dispersion in water. The Tb-H 4 L CP emitted the characteristic green fluorescence through antenna effect from H 4 L which was an excellent antenna molecule when excited at 270   nm and could be used to selectively determine Fe 3+ and polychlorinated benzenes based on fluorescence quenching effect. The coordination between Fe 3+ and carboxylic oxygen of Tb-H 4 L to damage the antenna effect and polychlorinated benzenes absorb the excitation light to result the inner-filter effect of fluorescence, which quenched the fluorescence of Tb-H 4 L CP. The linear range for Fe 3+ was 2.0–100   μM with a detection limit of 0.7   μM and for 1,3,5-trichlorobenzene was 0–0.44   ×   10 3   ppm with a detection limit of 0.087   ppm. The Tb-H 4 L CP demonstrates excellent fluorescence sensing performances, indicating that it can be used as a multi-response sensor to effectively measure toxic and harmful substances.