A. Sanchezmisiego et al., VARIABILITY OF THE SLOPES OF STANDARD ADDITION PLOTS IN THE ANALYSIS OF COPPER IN SEAWATER BY ANODIC-STRIPPING VOLTAMMETRY, Electroanalysis, 8(6), 1996, pp. 534-538
Copper in seawater was analyzed with a 'hybrid' mercury film-glassy ca
rbon electrode using linear sweep, square wave and differential pulse
anodic stripping voltammetry. The analyses were made in HCl (pH 2) and
ethylenediamine (EN)-spiked seawater (9 < pH < 10), with and without
purging the sample of dissolved oxygen. The relative slopes of the sta
ndard addition plots were used to determine the effect of mode and med
ia alteration on the results. Square-wave voltammetry in EN-altered se
awater, without oxygen purging, was found to be not only the most prac
tical technique, but also highly sensitive. The 'chemistry' of the oxi
dation reaction during the stripping step was found to affect the expe
rimental results markedly. For this reason, the peak current is an exp
erimentally dependent measure of the ion flux, both, into and out of t
he electrode.