title: Determination of 2-, 3-, 4-methylpentanoic and cyclohexanecarboxylic acids in wine: development of a selective method based on solid phase extraction and gas chromatography-negative chemical ionization mass spectrometry and its application to different wines and alcoholic beverages.
abstract: A method to analyse 2-methylpentanoic, 3-methylpentanoic and 4-methylpentanoic acids as well as cyclohexanecarboxylic acid has been developed and applied to wine and other alcoholic beverages. Selective isolation with solid phase extraction, derivatization with 2,3,4,5,6-pentafluorobenzyl bromide at room temperature for 30 minutes, and further analysis by gas chromatography-mass spectrometry in negative chemical ionization mode provides detection limits between 0.4 and 2.4 ng/L. Good linearity up to 3.6 μg/L, satisfactory reproducibility (RSD<10%) and signal recovery of around 100% represent a robust method of analysis. Concentration data of these analytes in wine and other alcoholic beverages are reported for the first time. The levels found ranged from the method detection limits to 2630 ng/L, 2040 ng/L and 3810 ng/L for 2-, 3- and 4-methylpentanoic acids, respectively, and to 1780 ng/L for cyclohexanecarboxylic acid. There are significant differences depending on the type of wine or beverage. Distilled beverages, beer and aged wines have higher contents in methylpentanoic and cyclohexanecarboxylic acids.
authors.affiliation: Laboratorio de análisis del aroma y enología, Departamento de Química Analítica, Facultad de Ciencias, Aragon Institute of Engineering Research (I3A), Universidad de Zaragoza, E-50009 Zaragoza, Spain. Electronic address: elisagm@unizar.es.
authors.forename: Elisa
authors.initials: E
authors.lastname: Gracia-Moreno
authors.affiliation: Laboratorio de análisis del aroma y enología, Departamento de Química Analítica, Facultad de Ciencias, Aragon Institute of Engineering Research (I3A), Universidad de Zaragoza, E-50009 Zaragoza, Spain.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Lopez
authors.affiliation: Laboratorio de análisis del aroma y enología, Departamento de Química Analítica, Facultad de Ciencias, Aragon Institute of Engineering Research (I3A), Universidad de Zaragoza, E-50009 Zaragoza, Spain.
authors.forename: Vicente
authors.initials: V
authors.lastname: Ferreira
mesh_terms: D000434:Alcoholic Beverages / Q000032:analysis; D001515:Beer / Q000032:analysis; D003509:Cyclohexanecarboxylic Acids / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D010421:Pentanoic Acids / Q000032:analysis*; D015203:Reproducibility of Results; D052616:Solid Phase Extraction / Q000379:methods; D021241:Spectrometry, Mass, Electrospray Ionization; D014920:Wine / Q000032:analysis*
chemical_list: D003509:Cyclohexanecarboxylic Acids; D010421:Pentanoic Acids; C044895:cyclohexanecarboxylic acid
keywords: 2-, 3- and 4-Methylpentanoic acids; Cyclohexanecarboxylic acid; GC-NCI-MS; SPE; Selective isolation; Wine