Electroanalytical Determination and Fractionation of Copper in Wine

Abstract

Eight different bottled wines (six red wines and two white ones) were studied for copper determination and fractionation. For this purpose, copper determination by square wave voltammetry (SWV) and potentiometry (PSA) stripping analysis using Hg electrodes (drop and film, respectively) were carried out. Two direct procedures for the determination of total copper in wine are proposed; in both cases, drastic treatment of samples is not necessary, the procedures are very fast (estimated time to carry out an analysis is <10 min) and require no deaeration. Fractionating treatment consists of various HCl additions followed by the addition of ethylenediamine. Precision (RSD < 3%) and accuracy (recovery > 98%) data justify that both methods proposed are valid for total copper determination in wine. The wines studied displayed similar behaviors regarding fractionation: the percentages of total copper fractionated in each step are statistically similar: differences are lower than 2 S.

Square-wave anodic-stripping voltammetric determination of Cd, Pb and Cu in wine: Set-up and optimization of sample pre-treatment and instrumental parameters

“…This is in agreement with the knowledge that sensitivity is higher for SWASV than DPASV and for MFE than HMDE [61,62,64,[106][107][108][109][110][111]. Compared with other techniques applied to wine analysis, it can be noted that the current method has a LOD two times lower than the SWASV method reported in the literature for the determination of Cu using a static mercury drop electrode [60], 20-30 times lower than DPASV [23], 10-300 times lower than AAS [23], and very similar to the LOD of the ICP-MS [37,112].…”

“…Considering the wine matrix our sensitivities are considerably higher than both that reported for Cu using SWASV with a static mercury drop electrode, i.e. 3.4 nA nmol −1 L min −1 [60], and those obtained using DPASV with a hanging mercury drop electrode, i.e. 1.0-1.5 (Cd, Pb) and 0.5-0.8 (Cu) nA nmol −1 L min −1 [53].…”

“…Trace metals (and trace elements in general) in wine are determined not only to guarantee wine quality, typicality and authenticity (especially using chemometric methods to identify the type of wine and/or its geographic origin) and in particular against fraud or adulteration [3][4][5][6][7][8][9][10], but also to evaluate possible contamination derived from environmental pollution [1,11,12], to monitor the content of substances added during the wine making process, and to demonstrate compliance with legal limits, especially for export purposes [2,13], as well as to assess the contributions the voltammetry (ASV), in differential pulse mode (DPASV) and linear sweep mode (LSASV) [17,19,22,23,27,36,[51][52][53][54][55][56], and potentiometric stripping analysis (PSA) [12,20,21,42,[56][57][58][59][60]. To our knowledge, square-wave anodic-stripping voltammetry (SWASV), i.e.…”

“…To our knowledge, square-wave anodic-stripping voltammetry (SWASV), i.e. the most sensitive of all voltammetric methods [61][62][63][64] has been applied only in one work [60] and only for copper determination using a static mercury drop electrode. Moreover no general set-up of the instrumental parameters and their optimization have so far been reported.…”

Investigation on possible relationships between the content of sulfate and selected metals in Chianti wines

“…The six samples 001-006 showed relatively high concentrations of copper (0.46(1)-0.93(2) mg/L), whereas samples 007-011 showed limited values (0.14(4)-0.36(4) mg/L). Wide ranges for copper concentration in wines have been previously found and reported by others including: 0.056-0.764 mg/L (color and region undefined; Schiavo et al, 2008); 0.031-0.313 mg/L red Hungarian wines (Ajtony et al, 2008); 0.5-1.0 Italian Marsala dessert wines (Dugo et al, 2005); 0.2-0.6 mg/L Cretan wines (color undefined; Galani-Nikolakaki et al, 2002); 0.076-0.114 mg/L red wines (region undefined; Sá nchez Misiego et al, 2004); 0.347-0.487 mg/L red Italians wines (from Umbria, Campania and Piemonte regions; Buldini et al, 1999). The comparative analysis suggests that, for the samples 001-006, copper was in some way added (to vines or/and to wines).…”