MODIFIED GRAPHITE/GRAPHENE DOT MICROSENSORS FOR THE ASSAY OF TRACE AMOUNTS OF LEAD AND CADMIUM IN WATER CATCHMENTS AREAS USING DIFFERENTIAL PULSE ANODIC STRIPPING VOLTAMMETRY

摘要

In this study, dot microsensors based on graphite/graphene paste modified with iron (Ⅱ) phthalocyanine, nickel (Ⅱ) phthalocyanine and 5,10,15,20-tetra(4pyridyl)21H, 23H porphine chloride tetrakis(methochloride) manganese(Ⅲ) were used for the determination of trace amounts of lead and cadmium from various water catchments areas using differential pulse anodic stripping voltammetry. The response of the proposed dot microsensors were sensitive enough to detect very low levels of both metals ions in drinking water resources to take corrective action for the supply of safe and suitable drinking water. The lowest limits of quantification for lead is 0.00207 μg L~(-1) and for cadmium 5.6 μg L~(-1), with a correlation coefficient (R~2) between 0.9951 and 0.9981 for lead, and between 0.9951 and 0.9984 for cadmium. The recovery of Pb(Ⅱ) and Cd(Ⅱ) in water samples were higher than 93.06 % with RSD(%) values lower than 0.29%. These results of the proposed dot microsensors compared favorably with the results from a standard ISO certified method.