title: Determination of volatile compounds in grape distillates by solid-phase extraction and gas chromatography.
abstract: Solid-phase extraction (SPE) procedure on octadecylsilica (C18) was developed for accumulation of volatile compounds from grape distillates. The procedure was optimised for final analysis by capillary gas chromatography. At mass concentrations in model solutions ranging from 0.1 to 50 mg/l solid-phase extraction recoveries of all analytes ranged from 69% for 2-phenylethanol to 102% for capric acid, with RSD values from 2 to 9%. SPE recoveries of internal standards to be added in the sample solution prior to extraction, higher alcohols 2-ethyl-1-hexanol and 1-undecanol, were 97 and 93%, respectively, with RSD values of 3%. Detection limits of analyzed compounds in model solutions ranged from 0.011 mg/l for isoamyl acetate to 0.037 mg/l for caproic acid. Method efficiency was tested in relation to acetic acid content, volume fraction of ethanol and possible matrix effects. A significant influence of matrix on SPE efficiency for geraniol, cis-2-hexen-1-ol and cis-3-hexen-1-ol was detected. For the same reason, 2-phenylethanol could not be determined by developed SPE method in samples of grape distillates. The developed solid-phase extraction method was successfully applied to determine the differences in volatile compound content in different grape distillates produced by the distillation of crushed, pressed and fermented grapes.
authors.affiliation: Institute of Agriculture and Tourism, Karla Huguesa 8, 52440 Porec, Croatia. igorl@net.hr
authors.forename: Igor
authors.initials: I
authors.lastname: Lukić
authors.forename: Mara
authors.initials: M
authors.lastname: Banović
authors.forename: Dordano
authors.initials: D
authors.lastname: Persurić
authors.forename: Sanja
authors.initials: S
authors.lastname: Radeka
authors.forename: Barbara
authors.initials: B
authors.lastname: Sladonja
mesh_terms: D000327:Adsorption; D000473:Alkanes; D005591:Chemical Fractionation; D002849:Chromatography, Gas / Q000295:instrumentation / Q000379:methods*; D009812:Odorants / Q000032:analysis; D058428:Silica Gel; D012822:Silicon Dioxide; D027843:Vitis / Q000737:chemistry*; D014835:Volatilization
chemical_list: D000473:Alkanes; D058428:Silica Gel; D012822:Silicon Dioxide; C022883:octadecane