Coordination Polymer as a Self-Calibrated pH and Amikacin Luminescence Probe

By the solvothermal assembly of Gd(NO3)3·6H2O, H2dht (H2dht = 2,5-dihydroxyterephthalic acid), and H4adip (H4adip = 5,5′-(anthracene-9,10-diyl)diisophthalic acid), a luminescent coordination polymer (CP) [Gd(adip)1/2(dht)1/2(NMP)2] (1, NMP = N-methylpyrrolidone) has been prepared. 1 exhibits dual emission bands and has the fluorescence turn-on behavior toward pH and antibiotic amikacin (AMK). Therefore, 1 can serve as a luminescence turn-on self-calibrated sensing material to quantitatively detect pH value and AMK. In the pH range of 5.05–6.88, the sensitivity can reach 2296% per pH, which is the highest among all fluorescence pH sensors. 1 also shows excellent sensing properties for AMK, and a good linear relationship between the fluorescence intensity ratio and concentrations of AMK was observed with a slope of 1.2 × 105 M–1. The limit of detection (LOD) is 7.7 × 10–8 M. Meanwhile, 1 is also the first CP-based sensing material to detect AMK. In order to better understand the sensing phenomenon, we also discussed the sensing mechanism for pH and AMK in detail.