ABSTRACT
A new poly(vinylchloride) (PVC) membrane electrode based on tannin from the bark of Quercusmacrolepis (acorn) as the ionophore was prepared and modified onto the surface of a gold electrode. The electrochemical impedance spectroscopy (EIS) technique was used to study the sensitivity of the electrode that was modified with a thin layer of polymeric biomembrane, in order to detect heavy metals ions in solution. The device shows a good sensitivity for Zn(2+), Ni(2+) ions and a little less for Cd(2+). The electrode indicates a good linear response for the three metals over a wide concentration range from 1.0×10(-9) to 1.0×10(-4) M, with a detection limit of 1.0×10(-9) M.
Subject(s)
Biosensing Techniques/instrumentation , Dielectric Spectroscopy/instrumentation , Metals, Heavy/analysis , Quercus/chemistry , Tannins/chemistry , Water Pollutants, Chemical/analysis , Electrodes , Environmental Monitoring/instrumentation , Equipment Design , Equipment Failure Analysis , Metals, Heavy/chemistry , Polyvinyl Chloride/chemistry , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
Planar electrochemical microcells were micromachined in a microcrystalline boron-doped diamond (BDD) thin layer using a femtosecond laser. The electrochemical performances of the new laser-machined BDD microcell were assessed by differential pulse anodic stripping voltammetry (DPASV) determinations, at the nanomolar level, of the four heavy metal ions of the European Water Framework Directive (WFD): Cd(II), Ni(II), Pb(II), Hg(II). The results are compared with those of previously published BDD electrodes. The calculated detection limits are 0.4, 6.8, 5.5, and 2.3 nM, and the linearities go up to 35, 97, 48, and 5 nM for, respectively, Cd(II), Ni(II) Pb(II), and Hg(II). The detection limits meet with the environmental quality standard of the WFD for three of the four metals. It was shown that the four heavy metals could be detected simultaneously in the concentration ratio usually measured in sewage or runoff waters.
