Optimization and Validation of a Microwave Digestion Method for Multi-element Characterization of Vranec Wines

Abstract

An analytical method for determination of multielement composition of Vranec wines using microwave digestion for sample preparation and inductively coupled plasma mass spectrometry (ICP-MS) was optimized and validated. Best recoveries, ranging from 87 to 114 %, were obtained for all analyzed elements, using a volume of 5 mL wine and 5 mL HNO 3 for sample microwave digestion. In total, 38 elements (Ag, Al, As, B, Ba, Be, Bi, Ca, Cd, Co, Cr, Cs, Cu, Fe, Ga, Ge, In, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Pd, Rb, S, Sb, Se, Si, Sn, Sr, Te, Ti, Tl, V, Zn) were determined in wines. The calibration curves of all elements were linear with correlation coefficients (R 2 ) ranging from 0.9920 for 11 B to 1.0000 for 53 Cr and 88 Sr. The accuracy of the method was checked with a standard addition method showing good repeatability and reproducibility (relative standard deviation, RSD <10 %). Vranec wines were fermented with Saccharomyces cerevisiae yeast strains commercial Clos, RC212, D254, and BDX, and six autochthonous Vinalco yeasts. The content of total elements in all Vranec wines ranged between 348 to 678 mg/L, observing lower amounts in wines fermented with the autochthonous Vinalco yeast. The content of harmful elements, such as Pb and Cu, was below the maximal allowed concentration in all wines.

Multi-element composition of red and white wines from Bujoru, Smulti and Oancea wine center, Romania

“…The average data shows that the highest concentration of Cd was obtained to red wines (0.17 µg/L) compared to white wines white (0.11 µg/L), the highest concentration of U was obtained to red wines (0.25 µg/L) compared to white wines white (0.24 µg/L) while the highest concentration of Hg was obtained to white wines (0.24 µg/L), compared to white wines white (0.20 µg/L). The results agree with some studies [12] 0.25 µg/L (Cd), 0.11 µg/L (U), [13] 0.14 µg/L (Cd), but compared with other result [14], the concentration of Cd was significantly higher than ours 10.60 µg/L (Cd). Regarding Hg concentration the results agree with those made in Romania [15] for Sauvignon Blanc 0.56 µg/L, Feteasca Alba 0.22 µg/L and Riesling 0.16 µg/L.…”

“…The average data shows that a higher concentration of As was obtained in white wines (12.45 µg/L) as compared to red wines (11.42 µg/L), while the higher concentration of Co was recorded for red wines (5.58 µg/L) as compared to white wines (5.09 µg/L) ( Table 1). The results are comparable with those obtained in Serbia [13] 16.1 µg/L (As) for red wines and 9.46 (As) µg/L for white wines, in Macedonia [14] 11.7 µg/L (As) by using the same microvinification technology, in Romania [15] 21.12 µg/L (As) and 154.90 µg/L (Sr), and higher compared to the results obtained in Italy [16] 2.91 µg/L for As, but for Sr the results obtained are significantly lower compared to the results obtained in Italy [16] 1340 µg/L (Sr). Regarding Co concentration the results agree with other studies made in Macedonia [12,14] 3.9 µg/L and 13.90 µg/L for Co, and in Serbia [13] 3.89 µg/L (Co) for red wines and 3.96 (Co) µg/L for white wines.…”

Rapid Determination of Trace Elements in Macedonian Grape Brandies for Their Characterization and Safety Evaluation

“…Repeatability describes the precision of within-run replicates, and reproducibility describes the precision of between-run replicates (Miller and Miller 2000). Precision of the method was defined as a relative standard deviation (RSD) calculated as a percentage using the standard deviation divided by the mean of replicated samples (Ivanova-Petropulos et al 2016). Thus, repeatability was checked with ten replicated measurements on B1 sample performed within 1 day.…”

Classification of wines according to several factors by ICP-MS multi-element analysis

“…For this reason, the stage of pre-treatment of samples in wine mineral analysis can be time-consuming, labor-intensive, and prone to potential contamination problems, as it is a very delicate stage and one that must be properly carried out. The preparation of wine samples for mineral elements determination includes microwave-assisted acid digestion, UV-assisted digestion, thermal digestion in an open reactor, sample dilution, dry and wet ashing, and also less common approaches such as de-alcoholization or analyte separation (Gonzálvez et al, 2008;Ivanova-Petropulos et al, 2016). Moreover, when choosing the method of wine sample preparation, one must consider which procedure provides the best results in the shortest time, with minimum losses and contamination risks, consumes the smallest quantities of reagents and samples and generates the smallest amount of residue and waste (Gonzálvez et al, 2008).…”