Determination of lead in blood by square wave anodic stripping voltammetry at a carbon disk ultramicroelectrode

A method for blood lead ([Pb]) analysis is developed based on square wave anodic stripping voltammetry (SWASV) in an Hg(2+)-containing solution using a 10-microns-diameter carbon disk ultramicroelectrode. SWASV eliminates interference from O2 in unsparged blood-derived sample solutions, and filtration of acidified samples through nitrocellulose reduces the concentration of interfering substances, increasing the size and improving the uniformity of peak currents. Blood [Pb] values obtained by SWASV are compared with blood [Pb] values determined by graphite furnace atomic absorption spectrophotometry; good accuracy and reasonable coefficients of variation in the range 10.6-20% (average of 13.5%) are found for blood [Pb] ranging from 4 to 30 micrograms/dL. Preliminary experiments using a carbon disk microarray electrode suggest future improvements in sensitivity.