Evaluation of thermal desorption and solvent elution combined with polymerentrainment for the analysis of volatiles released by leaves from midge (Dasineura tetensi) resistant and susceptible blackcurrant (Ribes nigrum L.) cultivars

Polymer entrainment combined with solvent elution or thermal desorption, st eam distillation and solvent surface extractions has been applied to leaves from midge-resistant and -susceptible blackcurrant cultivars, Irrespective of the methods used, the predominant compounds detected were terpene hydro carbons, but only minor quantitative differences were found in the relative concentrations of the individual mono- and sesqui-terpenes identified. Bot h steam distillation and thermal desorption resulted in the formation of a number of artefacts, whilst the use of polymer entrainment revealed the pre sence of a number of compounds, including a homoterpene not detected by eit her steam distillation or leaf surface solvent extraction. The relative mer its of the various methods used are discussed in relation to their potentia l value for the identification and quantification of leaf surface volatiles . Copyright (C) 1999 John Wiley & Sons, Ltd.