Comparison of sample preparation techniques for multielemental analysis of wine samples by ICP-MS

Abstract

The aim of this study was the comparison of different sample preparation methods for multielemental ICP-MS analysis of wine samples. All investigated methods were previously published for the same purpose, but the comprehensive comparison was carried out in the frame of this study for the first time. Five wine samples of different residual sugar content (2 dry, 2 sweet and one extra fine quality dessert wine) were used from Hungarian wine districts. Due to the lack of certified reference materials method validation and cross-checking was carried out by using two different types of inductively coupled plasma mass spectrometers (ICP-MS), namely a quadrupole based ICP-MS equipped with a collision cell (ICP-CC-MS) and a high resolution sector field ICP-MS (ICP-SF-MS). The measured elements were Li, Mg, B, Al, Cu, Rb, Sr, Zr, Cd, Ba, Tl, Pb, Bi, U, Cr, Fe, Mn, Co, Ni, Zn, As, Mo and Ga.Sample preparation procedures were based on sample dilution, microwave digestion using nitric acid (in combination with and without evaporation prior to ICP-MS analysis) and a mixture of nitric acid and hydrogen peroxide. The investigation resulted that the optimal digestion method for the above-mentioned purpose is microwave digestion using nitric acid without evaporation. The advantages and disadvantages of the investigated methods are critically discussed.