title: Development of a mixed-mode solid phase extraction method and further gas chromatography mass spectrometry for the analysis of 3-alkyl-2-methoxypyrazines in wine.
abstract: A new method for analysing 3-isopropyl-2-methoxypyrazine, 3-sec-butyl-2-methoxypyrazine and 3-isobutyl-2-methoxypyrazine in wine has been developed and applied to wine. The analytes are extracted from 25 mL of wine in a solid-phase extraction cartridge filled with 60 mg of cation-exchange mixed-mode sorbent. Analytes are recovered with triethylamine in dichloromethane and the organic extract is analysed by GC-SIM-MS using 3-isopropyl-2-ethoxypyrazine as internal standard. The detection limits of the method are in all cases under 1 ng/L, below the olfactory thresholds of the compounds in wine. The repeatability of the method is around 15% for levels in wine of 2 ng/L. Linearity is satisfactory and recoveries are in all cases close to 100% with RSD between 13% and 20%. The method has been applied to the analysis of 12 Chilean white and 8 Spanish red wines. The levels found suggest that 3-alkyl-2-methoxypyrazines can exert a significant sensory contribution to the aroma of Chilean Sauvignon Blanc wines, while most likely they play a nearly negligible role on traditional Ribera and Rioja Spanish red wines.
authors.affiliation: Departamento de Química Analítica, Facultad de Ciencias, Instituto de Investigación en Ingeniería de Aragón I3A, Universidad de Zaragoza, C/Pedro Cerbuna 12, 50009 Zaragoza, Spain. riclopez@unizar.es
authors.forename: Ricardo
authors.initials: R
authors.lastname: López
authors.forename: Elisa
authors.initials: E
authors.lastname: Gracia-Moreno
authors.forename: Juan
authors.initials: J
authors.lastname: Cacho
authors.forename: Vicente
authors.initials: V
authors.lastname: Ferrreira
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D016014:Linear Models; D009812:Odorants / Q000032:analysis; D011719:Pyrazines / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D052616:Solid Phase Extraction / Q000379:methods*; D014920:Wine / Q000032:analysis*
chemical_list: D011719:Pyrazines; C024267:2-isopropyl-3-methoxypyrazine; C034376:2-isobutyl-3-methoxypyrazine