Mt. Arcos et al., STUDY OF LABILITY OF HEAVY-METALS IN WINES WITH DIFFERENT DEGREES OF AGING THROUGH DIFFERENTIAL-PULSE ANODIC-STRIPPING VOLTAMMETRY, Journal of agricultural and food chemistry, 41(12), 1993, pp. 2333-2339
DPASV is a precise, highly sensitive, low-cost analytical technique wh
ich allows for the determination of total content of trace metals and
at the same time provides information on the stability of metal-ligand
unions. In this study, the content of Zn, Cd, Pb, and Cu in three win
es with different aging periods subjected to three different treatment
s (digestion, acidification to pH 1, and dilution) was studied to dete
rmine total metal concentration and distinguish the labile fraction fr
om that displaceable by acids. Previously, the influence of deposition
time and sample volume on potential and intensity of each metal was s
tudied. Zn is the cation with the greatest total content and lability.
Pb is complexed to the natural pH of wine but is easily displaceable
at pH 1. Cu forms very strong unions at pH 1, and stability is even gr
eater if the wine is young and organic matter is not very oxidized. Co
ncentration of Cd is approximately 1 mu g/L.