A comparison between two systems of volatile sampling in flowers of alfalfa (Medicago sativa L.)

A steam distillation method and dynamic headspace system with Tenax adsorbe nt resin were used to collect volatile components from alfalfa flowers. Aft er GC and GC/MS analyses several components were identified by both techniq ues and qualitative and quantitative differences were found. Aldehydes were the most abundant compounds detected with the Tenax method, and quantified as 52.7% of the total volatiles. Alcohols and ketones were also detected i n 23.5% and 19.6% amounts, respectively. In the steam distillate, alcohols represented 65.0% of the total, followed by aldehydes (19.5%) and ketones ( 2.9%). In addition, other classes of components were detected, such as este rs, terpenes, hydrocarbons and some miscellaneous compounds, although in co nstantly low amount. Acids were only detected in the steam distillate. Diff erences in qualitative and quantitative composition of volatiles obtained f rom the two methods were examined and discussed. Copyright (C) 2000 John Wi ley & Sons, Ltd.