Multi-bioapplicable fluorescence chemosensor for sequentially identifying gallium ion and pyrophosphate: Application to environmental samples, human serum, zebrafish and celery

A multi-bioapplicable fluorescence chemosensor MQV, ((E)-2-methoxy-6-((2-(quinolin-2-yl)hydrazineylidene)methyl)phenol), was developed for sequential detection of Ga³⁺ and pyrophosphate (PPi) ions. The addition of Ga³⁺ and PPi to MQV in sequence strongly caused an off-on-off fluorescent response in PBS buffer/DMSO (8:2, v/v, pH 7.4). The detection limits of MQV to Ga³⁺ and PPi were calculated as 3.00 μM and 4.49 μM, respectively. The 1:1 association mechanism of MQV to Ga³⁺ was determined using ¹H NMR titration, Job plot and DFT calculations. The reliability of MQV for the practical detection of Ga³⁺ and PPi was demonstrated in real water samples like drinking, tap, river, seawater, and sewage. Notely, we affirmed the possibility for sequential detection of Ga³⁺ and PPi by MQV in biological systems such as human blood serum, living zebrafish, and fresh celery. In human serum, MQV signaled linearly in 0–125 μM toward Ga³⁺ and PPi under detection limits of 10.50 μM and 12.94 μM, respectively. Surprisingly, MQV is the first case to detect Ga³⁺ via fluorescence change in plant and to sequentially detect Ga³⁺ and PPi in living zebrafish and plant.