Searching the Most Appropriate Sample Pretreatment for the Elemental Analysis of Wines by Inductively Coupled Plasma-Based Techniques

Abstract

Different sample preparation methods were evaluated for the simultaneous multielement analysis of wine samples by inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS). Microwave-assisted digestion in closed vessel, thermal digestion in open reactor, and direct sample dilution were considered for the determination of Li, Be, Na, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Y, Mo, Cd, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Tl, Pb, and Bi in 12 samples of red wine from Valencia and Utiel-Requena protected designation of origin. ICP-MS allows the determination of 17 elements in most of the samples, and using ICP-OES, a maximum of 15 elements were determined. On comparing the sample pretreatment methodology, it can be concluded that the three assayed procedures provide comparable results for the concentration of Li, Na, Mg, Al, K, Ca, Mn, Fe, Zn, and Sr by ICP-OES. Furthermore, ICP-MS data found for Cu, Pb, and Ba were comparable. Digestion treatment provides comparable values using both total decomposition in open system and microwave-assisted treatment for Cu by ICP-OES and for Cr, Ni, and Zn by ICP-MS. Open vessel total digestion provides excess values for Cr, Mn, Fe, and Zn by ICP-OES and defect values for Se. However, direct measurement of diluted wine samples provided uncomparable results with the digestion treatment for Mn, Cu, Pb, Zn, Ba, and Bi by ICP-OES and for Mg, Cr, Fe, Ni, and Zn by ICP-MS. Therefore, it can be concluded that microwave-assisted digestion is the pretreatment procedure of choice for elemental analysis of wine by ICP-based techniques.

Determination of Metals and Metalloids in Wine Using Inductively Coupled Plasma Optical Emission Spectrometry and Mini-torch

“…The ICP OES technique has been extensively employed in the determination of trace elements in wine (Péres-Jordán et al 1998;Gonzálvez et al 2008;Rodrigues et al 2011;Alkiş et al 2014). Despite many advantages of this technique, one of the main problems is the high consumption of plasma-forming gas.…”

“…For the determination of elemental composition of wines, it is required to properly prepare the samples. Taking into consideration that wine is a complex water-ethanol mixture, containing various inorganic and organic substances at different levels (Álvarez et al 2007;Pyrzyńska 2007;Gonzálvez et al 2008;Moreno et al 2008;Voica et al 2009;Rodrigues et al 2011), the sample preparation stage is very important in the analysis of particular wine components. The preparation of wine samples for metal and metalloid determination includes microwave-assisted acid digestion, UV-assisted digestion, thermal digestion in an open reactor, sample dilution, dry Electronic supplementary material The online version of this article (doi:10.1007/s12161-016-0567-6) contains supplementary material, which is available to authorized users.…”

Determination of Pb and Cd in Macedonian Wines by Electrothermal Atomic Absorption Spectrometry (ETAAS)

“…Wine is a complex matrix, containing high ethanol content and other organic compounds, and therefore, sample pretreatments, such as dilution, extraction ion exchange, precipitation or heating the samples (digestion) with HNO 3 , HClO 4 and H 2 SO 4 or mixtures of these acids, are commonly used methods (Castiñeira Gómez et al 2004;Gonzalvez et al 2008;Álvarez et al 2007). In order to abbreviate and speed up the analysis, determination of some elements in wine by ETAAS can be performed without sample preparation or simple dilution can be applied.…”

Evaluation of the multi-element capabilities of collision/reaction cell inductively coupled plasma–mass spectrometry in wine analysis

“…These solutions represent the matrices obtained after 5-fold and 10-fold wine dilution with high purity water, respectively (i.e. the most widely employed dilution factors reported in the literature to reduce non-spectral interferences when dealing with elemental analysis of wine [6,8,22]); and (iii) a 7% w w -1 nitric acid solution plus 200 mg L -1 of K, 10 mg L -1 of Ca and of Mg, and 2 mg L -1 of Na. This represents the matrix obtained after nitric acid digestion of 5 mL of wine followed by aqueous dilution to 50 mL (thus corresponding to 10-fold sample dilution) [8].…”

“…However, the analysis of wine by ICP-MS is not straightforward due to the effects caused by the wine matrix [5]. Several strategies have already been employed to address spectral and non-spectral interferences caused by the wine matrix: appropriate sample pre-treatment [6], targeted optimization of the operating conditions, e.g. use of cool plasma conditions, optimizing the nebulizer gas flow rate) [7,8], the use of aerosol desolvation [8,9] or electrothermal vaporization [10], the use of mathematical equations for interference correction [11] or the use of an ICP-MS instrument equipped with a sector field mass spectrometer operating at higher mass resolution [12,13].…”