QUANTITATIVE-DETERMINATION OF TRACE AND ULTRATRACE FLAVOR 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 odorant s of wine has been developed. The method combines a two-step preconcen tration stage (demixing+microextraction) and a GC-ion trap MS determin ation. 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-trich lorotrifluoroethane (freon 113) and analysed by GC-MS to obtain quanti tative information on 25 analytes whose concentrations range from 0.1 to more than 1000 mu g/l. Those analytes are esters, alcohols, terpeno ls, aromatic ketones, lactones, ethers and Volatile phenols. The overa ll method R.S.D. ranges from 3 to 7%, and the linear behaviour is very good except for the most concentrated analytes. Standard addition exp eriments and analyses of spiked samples have demonstrated that both th e MS quantification and the overall method are free of matrix effects, and that only two internal standards are needed. The limits of detect ion range from 20 to 1000 ng/l, and all the analytes can be detected a t the concentration in which they become flavour active. (C) 1998 Else vier Science B.V.