A SIMPLE QuEChERS METHOD FOR THE DETERMINATION OF MULTICLASS POLYPHENOLS IN WINES

FONTANA, A.; ANTONIOLLI, A.; SILVA, M.F.; BOTTINI, R.

Tenerife

Simposio; 20th International Symposium on Electro- and Liquid Phase- Separation Techniques; 2013

Phenolic composition is one of the most important quality parameters of wines, contributing to several organoleptic characteristics such as bitterness, astringency, color, flavor, odor, and oxidative stability. These compounds also have biological effects namely antioxidant, anti-inflammatory, anticarcinogenic, antimutagenic and antiproliferative activities. Wine may be an important source of polyphenols in the diet, so their characterization and determination in wine samples is a topic of increasing interest. In this sense, the development of new and reliable sample preparation techniques for such complex matrix is relevant for sample characterization purposes. The objective of this work was the development and validation of a simple, fast, inexpensive and robust procedure for the identification and quantification of ten phenolic compounds representatives of different chemical classes (phenolic acids, flavanols, flavonols and stilbenes) in wines based on a QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method prior to HPLC-UV-Vis multi-wavelength. Five milliliter wine sample were acidified with formic acid and extracted with 2.5 mL Acetonitrile. For phase separation, 1.5 g of sodium chloride and 4 g anhydrous MgSO4 were added; the tubes were vigorously hand-shaked for 1 min and centrifuged for 10 min at 3000 rpm. Thereafter, 1 mL of the acetonitrile layer was cleaned-up by DSPE with PSA and C18. The tube was vortexed for 1 min and centrifuged at 12.000 rpm for 2 min. Finally, an aliquot of extract was evaporated to dryness and the residue was taken up with the initial mobile phase (0.1 % Formic acid in Milli-Q water and 20 % of Methanol) and analyzed by HPLC-UV-Vis multi-wavelength. Considering matrix-matched calibration as quantification technique, recoveries higher than 75 % were obtained for red and white wine samples. A satisfactory linearity was observed in the range of 0.5-50 mg L-1 with r2 0.9989. The limits of detection (LODs) of the methodology were between 4 to 149 ng mL-1 for the studied analytes.  The intra and inter-day precision of the methodology, using wine samples spiked at 2 mg L-1 level were between 0.8 to 3.5 % for intraday  and 2.3 to 8.8 % for inter-day studies. The proposed method was applied to determine polyphenols in wine samples produced in Mendoza, Argentina. Nine phenolic compounds were determined with concentration ranged in between 0.3 to 43 mg L-1.