RESUMEN
The mutual influence of lead and cadmium ions on “in-situ” bismuth film coated glassy carbon electrode was demonstrated using different concentration target ions by changing ratio between Pb2+ and Cd2+. It is found that the presence of coexisting ions can have an influence on the detection of target ions. Especially for the detection of Cd2+, the existence of Pb2+ can be beneficial for the deposition of Cd due to the more positive deposition potentials. And the analytical performances of Cd2+and Pb2+ were obtained. The detection limit is 0. 5 μg/L towards Pb2+ with a linear range from 1-80 μg/L using 60 s deposition time. The resulting calibration plots of Cd2+ are linear over the range from 1-25 and 30-200 μg/L with the detection limit of 1 μg/L using 120 s deposition time. The bismuth film was finally employed to determine the Pb2+and Cd2+in real sample with good satisfied results.
RESUMEN
Poly(ethylene glycol)(PEG) coated silver nanowires has been hydrothermally prepared at a very slow rate, in which PEG was used as both a mild capping agent and a weak reductant. As-prepared silver nanowires(SNWs) have been characterized using scanning electron microscopy) and transmission electron microscope), which showed that the SNWs are usually longer than 100 μm and their diameters(each SNW has a uniform thickness) vary mainly in the range of 80～300 nm. Surprisingly, some of these silver nanowires connected) by their two ends to form some close-looped silver nanowires, which hitherto has not been reported elsewhere. The existence of close-looped silver nanowires supports the mechanism that nanowires can evolve from fusion of some nanoparticles and/or shorter nanorods. Careful TEM characterization and selected area electron) diffraction revealed that the silver nanowires kept a five-fold twinned structure, which is opposite to some reports) that a long-time incubation will lead to the disappearance of this twin structure. This work demonstrates the situation that deeper investigation is still needed for understanding the structure transformation of silver) nanowires.