ANODIC-STRIPPING VOLTAMMETRY OF TRACE-METALS BY BATCH INJECTION-ANALYSIS

The application of batch injection analysis to the determination of tr ace metals in samples of volume less than or equal to 100 mu l by squa re 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 analyt e ions have been studied and optimised procedures are recommended. Res ults for zinc, cadmium, lead and copper are presented, with particular emphasis on lead and cadmium, and nanomolar detection limits correspo nding to sub-picomole quantities found. Comparison is made with flow-i njection analysis and with experiments at wall-jet electrodes in conti nuous flow.