Detecting lead in a 3-electrode glass cell by square wave anodic stripping voltammetry

CREVELING 5

Lead is a highly toxic heavy metal that is carcinogenic to humans. Because lead can easily leach through the drinking water supply, water tests kits have been made readily available for the public to test their water at home to detect any traces of lead. The main disadvantage is that the majority of these kits cannot measure the amount of lead in water; they only show whether lead is present in water or not. One of the best analytical methods to quantify lead is by square wave anodic stripping voltammetry (SWASV). SWASV has the advantage over other voltammtery methods in that it has a very high sensitivity, meaning only a small sample is needed for testing, and rapid data acquisition. SWASV was applied in a 3-electrode glass cell experiment in order to detect lead in an aqueous solution. To further improve the detection of lead, the platinum working electrode was modified with activated carbon ink and bismuth, so that more lead ions were oxidized, therefore showing detection. After modifying the platinum working electrode and finding the optimal SWASV settings, the limit of detection (LOQ) and limit of quantification (LOQ) were determined to be 0.09 ppm and 0.31 ppm, respectively. In addition, the lowest concentration that can be visually detected was 0.50 ppm. Because 0.50 ppm is higher than the LOD and LOQ values, any lead concentration that is 0.31 ppm or higher can be assigned with high level of confidence.