Quantitative determination of trace and ultratrace flavour active compounds in red wines through gas chromatographic ion trap mass spectrometric analysis of microextracts

A GC-MS method for analysing the most important flavour active odorants of wine has been developed. The method combines a two-step preconcentration stage (demixing+microextraction) and a GC-ion trap MS determination. In the method, 50 mi of wine are previously adjusted to 13% (v/v) alcohol, and the alcoholic fraction is demixed by salting out. That fraction is partially rediluted, extracted with 0.1 mi of 1,1,2-trichlorotrifluoroethane (freon 113) and analysed by GC-MS to obtain quantitative information on 25 analytes whose concentrations range from 0.1 to more than 1000 mu g/l. Those analytes are esters, alcohols, terpenols, aromatic ketones, lactones, ethers and Volatile phenols. The overall method R.S.D. ranges from 3 to 7%, and the linear behaviour is very good except for the most concentrated analytes. Standard addition experiments and analyses of spiked samples have demonstrated that both the MS quantification and the overall method are free of matrix effects, and that only two internal standards are needed. The limits of detection range from 20 to 1000 ng/l, and all the analytes can be detected at the concentration in which they become flavour active. (C) 1998 Elsevier Science B.V.