An Environmentally Friendly, Cost-Effective Determination of Lead in Environmental Samples Using Anodic Stripping Voltammetry

摘要

Contamination of the environment with heavy metals such as lead presents many health risks. Simple, effective, and field-portable methods for the measurement of toxic metals in environmental samples are vital tools for evaluating the risks that these contaminants pose. This article describes the use of new developments in anodic stripping voltammetry (ASV) in an experiment that analyzes environmental samples for Pb content. In this experiment, students extract a sample such as riverbed sediment with dilute acid, facilitated by ultrasonic extraction, and analyze it for Pb using ASV. Owing to complex matrix effects of these samples, the standard addition method is used to determine the concentration of Pb. Determinations of Pb in sediment from the Little Miami River in Ohio showed average Pb levels of 9.3 ± 1.4 ppm. This experiment replaces traditional, costly working electrodes such as glassy carbon with inexpensive, disposable graphite pencil "lead" electrodes. Additionally, bismuth film electrodes are used, which are more environmentally friendly than traditional mercury films and eliminate the cost and hazards of mercury usage and disposal. The primary goal of this experiment is to teach the analytical electrochemical method of ASV for trace metal analysis, and it is targeted for an upper-level undergraduate instrumental methods course, with possible applications in an environmental chemistry course.