A poly(methyl methacrylate)-based capillary electrophoresis microchip, integrated with a microelectrode-based end-column amperometric detection, was described. A short unclosed portion of the separation channel from the detection cell was used as a working-electrode guide channel. With the aid of a three-dimension micropositioner and an optical microscope, a home-made 6 μm carbon-fiber microdisk electrode(tip diameter of 20 μm) was positioned along the guide channel at 30 μm distance from the channel outlet. With dopamine and catechol the as model analytes, the analytical performance of the system was demonstrated and the detection limit of 1.6×10 -7mol/L for dopamine was achieved, to our knowledge, which is the lowest value than that from published literatures using electrophoresis microchip with end-column amperometric detection.
The synthesis of the novel host compound carrying two spirobenzopyran groups was described.Its structure was confirmed by（）1H NMR,IR and elemental analysis.It was shown that the novel host can recognize lanthanide ions selectively with significant spectral shifts in visible region and enhanced absorbance.Thus,the compound can be used to recognize lanthanide ions by naked eyes. The selectivity was relative to size-fit effect.The order of spectral changes was Yb3+>Er3+>Gd3+>Dy3+>Eu3+>Pr3+>La3+,which is opposite to the order of the radii of lanthanide ions.We discussed the possible binding mechanism with analyzing the different UV-Vis spectral changes resulted by addition of the investigated ions.
