Anodic stripping voltammetry of trace metals by batch injection analysis

The application of batch injection analysis to the determination of trace metals in samples of volume ≤ 100 μl by square wave anodic stripping voltammetry has been investigated in detail, using a programmable electronic micropipette. The in situ formation of a mercury film on a glassy carbon electrode substrate, the influence of preconcentration time, injection rate and injected volume of analyte ions have been studied and optimised procedures are recommended. Results for zinc, cadmium, lead and copper are presented, with particular emphasis on lead and cadmium, and nanomolar detection limits corresponding to sub-picomole quantities found. Comparison is made with flow-injection analysis and with experiments at wall-jet electrodes in continuous flow.