ANYL 188 |
| The use of redox magnetohydrodynamics (MHD) to enhance the anodic stripping voltammetry (ASV) response of heavy metals has been investigated, with respect to achieving portability: disposable electrodes consisting of screen-printed carbon (SPC) on a low temperature co-fired ceramic (LTCC) substrate, small volumes, and permanent magnets. The analytes tested (Cd2+, Cu2+, and Pb2+) were codeposited on SPC with Hg2+ to form a Hg thin film electrode. High concentrations of Fe3+ were used to produce a high cathodic current which generates a significant Lorentz force in the presence of a magnetic field. This Lorentz force induces solution convection during the deposition step, enhancing the mass transport of analytes to the electrode and increasing their quantities preconcentrated into the mercury thin film. Therefore, larger ASV peaks and improved sensitivities are obtained, compared to analyses performed without a magnet. The effects on ASV signal of varying Hg2+ concentration (0.10 and 1.0 mM), deposition time (10-600 s), and electrode surface roughness were investigated. In addition, analyses were performed using a real lake water matrix. Using disposable LTCC-SPC working electrodes, small volumes (150 µL), and small permanent magnets (0.78 T), peak areas were increased by 75% when compared to the signal obtained in the absence of a magnetic field. Limits of detection on the order of 108 M were achieved with only a 1 min preconcentration time.
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General Session
7:00 PM-9:00 PM, Sunday, 26 March 2006 Georgia World Congress Center -- Ex. Hall B4, Poster
Sci-Mix
Division of Analytical Chemistry |