Lead is a toxic heavy metal ion that can cause a number of lasting health complications, especially in children. Behavioral issues, anemia, brain, liver, kidney, and nervous system damage have all been reported in children exposed to both acute high levels and chronic low levels of Pb2+. With this, the Environmental Protection Agency's (EPA) maximum contaminant level (MCL) in drinking water for Pb2+ is 15 ppb. Thus, pre-concentration and quantitative detection of Pb2+ is of profound importance. Cloud point extraction (CPE) is a well-known method for pre-concentrating analytes to detectable levels, but little is known about its applicability for electroanalytical methods such as anodic stripping voltammetry (ASV). We developed an ASV method for ultra-trace determination of Pb2+, achieving a limit of detection (LOD) of 0.27 ppb with a 2 min deposition time using a mercury-coated glassy carbon (Hg-GC) electrode. While this is a level 55 times lower than the EPA's MCL for drinking water, it represents a 6.2-fold increase in sensitivity and a 37-fold decrease in the LOD compared to Pb-ASV without CPE. CPE-ASV analysis was also completed on a bismuth-coated glassy carbon (Bi-GC) electrode and the results are compared to that obtained with Hg-GC. Determination of Pb2+ in environmental water samples with both film-electrodes was also demonstrated. This inexpensive, environmentally friendly method of extraction can potentially be applied to other heavy metal ions and organic compounds.

Cloud point extraction for electroanalysis: Anodic stripping voltammetry of lead

251st National Meeting (2016)

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