Deposition of trace metals on solid electrodes: experimental verification of limits of electrochemical preconcentration

Experimental data obtained by differential pulse anodic stripping voltammetry and electrothermal vaporization inductively coupled plasma atomic emission spectroscopy determinations of amounts of copper and lead deposited on glassy carbon electrodes essentially validate a recently published model for the process of preconcentration of metal ions by electrodeposition. Data elucidating the related phenomena of amount deposited, equilibrium concentration of unrecovered ions, and percent recovery have been determined and are discussed. For solution concentrations that allow multilayer electrode coverage (usually greater than 10{sup {minus}7} M), and monolayer or less electrode coverage, data show initial-concentration-dependent limits to electrochemical preconcentration, which decrease percent recovery. Electrodeposition parameters that minimize equilibrium concentration levels are discussed. The analytical importance of the verified model is that, for a set of experimental conditions, it allows calculation of predicted recoveries from data collected at macroconcentration levels to concentration levels 3 magnitudes lower.