Reversible terbium luminescent polyelectrolyte hydrogels for detection of H2PO4(-) and HSO4(-) in water.

Polyelectrolyte gels are promising soft networks that can accommodate various guest species and retain liquid nature. The incorporation of two novel silica based terbium complexes (Tb(a)(2) and Tb(b)(2)) in the poly(acrylamide) host can exhibit the characteristic green terbium emission in water. More interestingly, we noted that these target materials can selectively recognize H(2)PO(4)(-) (detection limit 10(-5) M) and HSO(4)(-) (detection limit 5 × 10(-5) M) compared with other anions, such as F(-), Cl(-), Br(-), and I(-). The fluorescence intensity ratios against both anions (H(2)PO(4)(-) and HSO(4)(-)) concentration all follow the simple linear equations by the least-squares fitting method.