Evaluation of Closed-Loop Stripping for the Isolation of Wine Aroma Compounds from Aqueous Solution

摘要

Closed-loop stripping analysis (CLSA) has traditionally been used to analyze drinking water samples contaminated with earthy-musty odorants. The purpose of this work was to investigate whether CLSA can provide a new approach to analyze wine and grape juice samples for important aroma compounds. Model aqueous solutions composed of four esters, three monoterpenes, and a C_(13)-norisoprenoid were chosen as a representative subset of typical wine aroma compounds. The results showed that CLSA could be applied to the analysis of wine fatty acid ethyl ester volatiles, as the recoveries were reasonable for quantitation. They were not dramatically affected by sampling time, temperature, or changes in ionic strength, making CLSA a rapid and simple method for their determination. The recovery of the C_(13)-norisoprenoid and the monoterpene alcohols using CLSA were more sensitive to changes, but under the conditions used the recoveries could be adjusted to at least 40% from aqueous solution. However, the addition of 11 and 12% ethanol markedly reduced the recoveries of the more polar analytes to a level that would make CLSA impractical under these experimental conditions. If the flow rate of the sweep gas were increased such that the time for trapping of the polar analytes were acceptable and if the amount of sorbent were increased so that breakthrough does not occur, CLSA could be a gentle, relatively rapid, and effective method for the isolation of wine volatiles.