Comparison of two pyrazole derived "turn on" fluorescent probes for the recognition of Ga3+

Two fluorescent probes (E)-N'-(2-hydroxybenzylidene)-1-(pyridin-2-yl)-5-(thiophen-2-yl)-1H-pyrazole-3-carbohydrazide (PTP) and (E)-N'-(4-(diethylamino)-2-hydroxybenzylidene)-1-(pyridin-2-yl)-5-(thiophen-2-yl)-1Hpyrazole-3-carbohydrazide (DPTP) were drafted and synthesized to detect Ga3+ through fluorescence turn on strategy. DPTP had a significant fluorescence enhancement compared with PTP after complexing with Ga3+ ions. The detection limit of DPTP (1.21 x 10-8 M) was lower than that of PTP (8.85 x 10-7 M). The Job's plot showed that both sensor PTP and DPTP bound to Ga3+ to form a 1:2 complex. In addition, DPTP could mimic INHIBIT logic function using Ga3+ and PPi being logic inputs and the fluorescence intensity at 466 nm as output signal. Furthermore, the application of DPTP to detect Ga3+ in actual water samples had also achieved satisfactory results and the test papers containing DPTP were fabricated successful for convenient detection of Ga3+.