Ap. Pollnitz et al., Determination of oak lactones in barrel-aged wines and in oak extracts by stable isotope dilution analysis, J CHROMAT A, 857(1-2), 1999, pp. 239-246
The cis- and trans-isomers of 5-butyl-4-methyl-4,5-dihydro-2(3H)-furanone,
the so-called oak lactones, are derived from oakwood, and the cis-isomer is
an important contributor to wine flavour. Their deuterium-labelled forms,
[H-2(4)]cis-oak lactone and [H-2(4)]trans-oak lactone, were synthesised fro
m the unlabelled analogues, and were utilised in a new method employing gas
chromatography-mass spectrometry to determine the concentration of these c
ompounds in wine or extracts of oak shavings in a single analysis. The meth
od can employ either liquid-liquid extraction or solid-phase microextractio
n, and is both rapid and accurate. There was some artefactual generation of
cis-oak lactone during the analysis of model wine extracts of unheated oak
shavings when diethyl ether extraction and injector block temperatures at
or above 225 degrees C were employed. (C) 1999 Elsevier Science B.V. All ri
ghts reserved.