Use of solid-liquid distribution coefficients to determine retention properties of Porapak-Q resins. Determination of optimal conditions to isolate alkyl-methoxypyrazines and beta-damascenone from wine.
The solid-liquid distribution coefficients of different analytes--all of which are important aroma compounds--between hydroalcoholic solutions or wines and different sorbents have been determined by measuring the amount of analyte removed by a given mass of sorbent in equilibrium with a given volume of standard solution. These data have shown that the best extraction conditions for non-polar compounds from wine are the use of Porapak-Q resins and 6% (v/v) alcoholic solutions. Phase ratio, hold-up volumes and number of plates for Porapak-Q beds have been measured in different experiments. With all these data it has been possible to calculate breakthrough volumes in good agreement with experimental results. The Lövkvist-Jönsson model is more appropriate for estimating breakthrough volumes of a 2-cm Porapak-Q bed. The model estimates that a 5-cm bed is needed to achieve a quantitative recovery of 3-alkyl-2-methoxypyrazines and beta-damascenone from 500 ml of wine (diluted to 1000 ml with water). Experimental results confirm the predictions of the model and show that in a single isolation step detection limits below 10 ng/l can be reached for these compounds using GC-MS detection.
Ortega
L
L
Department of Analytical Chemistry, Faculty of Sciences, University of Zaragoza, Spain.
López
R
R
Cacho
J
J
Ferreira
V
V
D002849:Chromatography, Gas / Q000295:instrumentation* / Q000379:methods; D045792:Norisoprenoids; D011719:Pyrazines / Q000302:isolation & purification*; D012015:Reference Standards; D013729:Terpenes / Q000302:isolation & purification*; D014920:Wine / Q000032:analysis*
D045792:Norisoprenoids; D011719:Pyrazines; D013729:Terpenes; C075388:beta-damascenone