DIRECT DETERMINATION OF CADMIUM AND LEAD IN WHOLE-BLOOD BY POTENTIOMETRIC STRIPPING ANALYSIS

The commercially available equipment for potentiometric stripping analysis (PSA) was tested for routine lead and cadmium determination in whole-blood samples. In contrast to anodic stripping voltammetry, PSA is not subject to background interferences from organic electroactive constituents in the sample or to the presence of dissolved oxygen (i.e., oxygen removal is not necessary). To determine lead and cadmium by PSA, it is sufficient to dilute the blood sample with an appropriate supporting electrolyte (0.5 mol/L HCI). The detection limit changes with deposition time and volume of blood sample used. For 1 mL of blood and a 1-min deposition time, the detection limit is 1 mug/L for both elements. If the deposition time increases to 10 min, cadmium can be determined at its normal concentration in blood (the detection limit is improved to <0.l mug/L). Procedures for routine determination of lead and cadmium in whole blood are presented.