科研之友
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摘要
Metal. organic framework materials (MOFs), formed by the coordination of inorganic metal ions and organic ligands, are a kind of new materials with porous network structure. MOFs possess many advantages such as a large specific surface area, developed pores, easy functionalization, and good stability. In the present, MOFs have been applied to many areas including solar batteries, biopharmaceuticals, catalysis and biosensors. But little attentions have been received on the application of MOFs as the sensing materials for analytical detection platform based on ion. selective electrodes. In this work, copper. based metal. organic frameworks (CuMOFs) with porous spherical structure were used as the sensitive carriers of ion. selective electrode, in which multi. walled carbon nanotubes (MWCNTs) with excellent conductivity and large surface area were doped. This resulted in the development of a sensitive solid carbon paste electrode for the detection of silver ion (Ag+). The experimental results demonstrated that the CuMOFs. based solid electrode had good selective potential response to Ag+. We investigated the effect of different content ratio of the sensing membrane CuMOFs and MWCNTS, and pH of the tested solution on the potential response. The obtained results suggested that the proposed solid carbon paste electrode containing CuMOFs and MWCNTs (99. 1, w/w) had the best near. Nernst potential response to Ag+ in HNO3 solution at pH 2. 0, suggesting that MWCNTs was favorable for promoting the electron transfer in the electrode interface. Under the optimal experimental conditions, the widest dynamic linear range was 5. 0 mu mol/L-0. 1 mol/L with the slope of 57.9 mV/dec and the detection limit of 3. 2 mu mol/L. This may be attributed to the effective interaction between CuMOFs and Ag+, which was proved by the UV-Vis spectra before and after CuMOFs interacted with Ag+. Furthermore, the solid ion. selective electrode displayed high selectivity for silver ions in the presence of other tested interfering ions, good stability, and fast and reversible potential response in different concentrations of Ag+ solution (20-40 s). Compared with other reported Ag+. selective electrodes based on other sensing carriers, the analytical sensitivity of MWCNTs. doped. CuMOFs solid carbon paste electrode were obviously improved. The developed electrode was preliminarily applied to the quantitative determination of Ag+ in the actual water samples collected from laboratory and lake, and the recoveries were satisfactory. This work is promising and potential to further extend the application of other MOFs in chemical sensors.
- 出版日期2018-11
- 单位西南大学
