FLOW-INJECTION POTENTIOMETRIC AND VOLTAMMETRIC STRIPPING ANALYSIS USING A DIALYSIS MEMBRANE COVERED MERCURY FILM ELECTRODE

Flow injection stripping analysis using a cellulose triacetate (CTA) polymer-modified mercury film electrode is described for the determination of lead in environmental and clinical samples. Commercially available CTA dialysis membranes were secured to a glassy carbon disc electrode using a Plexiglas cap in a wall-jet flow cell. Optimization of the flow cell dimensions and the stopped-flow protocol are described. Flow injection Osteryoung square-wave anodic stripping voltammetry and flow injection potentiometric stripping analysis (FI-PSA) are demonstrated to be effective for determining low ppb levels of lead in tap water, river water and sea-water. FI-PSA is also shown to be effective for urine and whole blood sample matrices. Bovine whole blood samples (10 mu l) were pre-treated by dilution (1 + 29) with 5% v/v HCl or by using the commercially available Metexchange M reagent. Lead was determined in certified. whole blood samples (188 ppb) with a precision of 10.6% and an accuracy of 4.91% (n = 8). The analysis time was 6 min per sample.