ABSTRACT Field sensors offer potential improvements over laboratory-based methods for heavy metal analysis because concentration assays of environmental specimens are more rapidly obtained. This allows easier pollution hot spot detection and minimizes artifacts caused by sample transport and storage. This research project involves a field sensor concept based on polarographic techniques. Polarography is an electroanalytical method that performs trace level analysis with speciation capability. Several modifications of basic laboratory methodology, though, are needed to produce a practical, portable polarographic field sensor. These include changes in instrumentation, power supply, data acquisition, experiment control, and methods of metal extraction from test samples. The use of cyclic voltammetry (CV) at a graphite substrate to analyze for lead in water and spoil bank samples is presented in this work. Cold acid extraction was employed for the spoil bank material. Based upon comparison of these measurements with accepted methods of laboratory extraction and metal analysis, it can be concluded that the CV/graphite method is a promising candidate for a heavy metal field sensor. Further technique development will include construction of a full field measurement prototype, extension to analysis of additional metals, and use of high surface area electrodes to lower concentration detection thresholds.
KEYWORDS: field sensors, polarography, heavy metals
This paper is from the Proceedings of the HSRC/WERC Joint Conference on the Environment, May 1996, published in hard copy and on the Web by the Great Plains/Rocky Mountain Hazardous Substance Research Center.
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