Two novel "turn on" fluorescent probes for the determination of Al3+and its applications

In this paper, two "turn on" fluorescent probes Y1 and Y2 were obtained by a simple one-step reaction, which can detect Al3+ based on the cation-induced CHEF (chelation enhanced fluorescence) effect. Both probes show highly selectivity, and the other common fifteen cations have no influence on the detection. What is more important, Y1 and Y2 also exhibit high sensitivity to Al3+, especially for Y2, their limits of detection (LOD) are 15.5 nM and 0.166 nM, respectively, which are lower than many effectively reported probes. Sensors Y1 and Y2 have a pincershaped structure which can combine with Al3+ to form a six-membered ring, strengthening complexing power. Job plots and ESI-MS revealed that both probes coordinated to Al3+ with the ratio 1:1, 1H NMR and DFT calculations demonstrated the probes combined with Al3+ through the tetracoordination process with one nitrogen atom in -NH and three oxygen atoms in two -OH and one C--O groups, respectively. Practical application including test strips, soil and Traditional Chinese Medicine (TCM) experiments manifest that these probes can be further used for Al3+ detection in various complex environments.