Fluorescence probe combines with fluorescence imaging technology has become the most powerful analytical method with their great advantages of high sensitivity and selectivity and real-time monitoring. Ni 2+ is widely distributed in food, environment and living animals, thereof, it is of great significance for detection Ni 2+ with high selectivity. Herein, a simple strategy is proposed to design and synthesiz a small molecule fluorescent probe Y1 by using “one-pot” method. The spectroscopic behaviors including UV–Vis absorption and fluorescence emission spectrum have been used to verify the feasibility of probe towards Ni 2+ in water/EtOH ( v / v = 2:8) mixtures under neutral condition. As expected, Y1 offers high selectivity and sensitivity for detection Ni 2+ in aqueous solution with a good linear relationship and low detection limit within Ni 2+ concentration variation from 0 to 13 μM ( DOL = 0.0038 μM, R 2 = 0.9983). It is remarkable that Y1 can be applied for real-time visualization Ni 2+ change in sprouted potato and zebrafish with great photo-stability, highlighting that the practicability and feasibility of Y1 to detect and monitor Ni 2+ in the field of food industry and biomedical field.
Herein, a cationic iridium(III) complex [(ppy) 2 Ir(IPP)]PF 6 (ppy: 2-phenylpyridine; IPP: 2-(1 H -imidazo[4,5- f ][1,10]phenanthrolin-2-yl)phenol) was synthesized. Under the excitation of 328 nm (λ ex = 328 nm) UV light, this complex emitted bright yellow orange light (500 ∼ 700 nm, λ em,max = 582 nm), the Stokes shift was up to 254 nm, mainly due to excited-state intramolecular proton transfer (ESIPT) occurring in its ancillary ligand IPP. [(ppy) 2 Ir(IPP)]PF 6 was very sensitive to Ni 2+ , which was caused by the ESIPT being hindered by the coordination of [(ppy) 2 Ir(IPP)]PF 6 with Ni 2+ . Its bright yellow orange light disappeared within 1 min when Ni 2+ (1.0 equiv.) was added in its solution (in DMSO/H 2 O, v/v = 999/1), therefore, it can be used for “turn-off” chemiluminescent detection of Ni 2+ . The recognition of [(ppy) 2 Ir(IPP)]PF 6 to Ni 2+ was not interfered by many common metal ions (such as Na + , K + , Li + , Mg 2+ , Al 3+ , Ca 2+ , Fe 3+ , Ag + , Zn 2+ , Hg 2+ , Co 2+ , Pb 2+ , Mn 2+ , Ba 2+ or Cr 3+ ), however, Cu 2+ was an interfering metal ion, but its interference can be completely masked by thiourea. The detection limit was as low as 3.31 × 10 −7 mol∙L -1 (0.331 μM). The Job’s plot analysis revealed that the stoichiometry of [(ppy) 2 Ir(IPP)]PF 6 with Ni 2+ was 1:1, its detecting mechanism based on ESIPT effect was demonstrated by 1 H NMR spectra and density functional theory (DFT) calculation.
Lulu Yu,Min Liu,Yanling Zhang,Yun Ni,Shaobo Wu,Ruijiang Liu
A magnetically induced self-assembly DNAzyme electrochemical biosensor based on gold-modified α-Fe2O3/Fe3O4 heterogeneous nanoparticles was successfully fabricated to detect Nickel(II) (Ni2+). The phase composition and magnetic properties of α-Fe2O3/Fe3O4 heterogeneous nanoparticles controllably prepared by the citric acid (CA) sol–gel method were investigated in detail. The α-Fe2O3/Fe3O4 heterogeneous nanoparticles were modified by using trisodium citrate as reducing agent, and the magnetically induced self-assembly α-Fe2O3/Fe3O4–Au nanocomposites were obtained. The designed Ni2+-dependent DNAzyme consisted of the catalytic chain modified with the thiol group (S1-SH) and the substrate chain modified with methylene blue (S2-MB). The MGCE/α-Fe2O3/Fe3O4–Au/S1/BSA/S2 electrochemical sensing platform was constructed and differential pulse voltammetry was applied for electrochemical detection. Under the optimum experimental parameters, the detection range of the biosensor was 100 pM–10 μM (R2 = 0.9978) with the limit of detection of 55 pM. The biosensor had high selectivity, acceptable stability, and reproducibility (RSD = 4.03%).
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