U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.


Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Main content area

Determination of 3-methyl-2,4-nonanedione in red wines using methanol chemical ionization ion trap mass spectrometry

Alexandre Pons, Valérie Lavigne, Philippe Darriet, Denis Dubourdieu
Journal of chromatography 2011 v.1218 no.39 pp. 7023-7030
acetone, acetonitrile, chromatography, derivatization, detection limit, ethyl acetate, ethyl ether, flavor, heptane, ionization, mass spectrometry, methanol, pentane, red wines
A compound associated with oxidized flavor in red wines was recently-identified as 3-methyl-2,4-nonanedione (MND). In order to quantify it, positive chemical ionization (PCI) in an ion trap was studied using conventional liquid reagents such as methanol, acetonitrile, and acetone, as well as non-conventional liquid reagents such as ethyl acetate, diethyl ether, pentane, isohexane, and heptane. Under laboratory conditions, very different response factors were obtained with MND depending on the gas. We also compared the detection limit of conventional CI with hybrid chemical ionization (HCI). Finally, this compound was quantified in red wines by liquid/liquid extraction without any derivatization steps, followed by GC/MS-CI analysis, using methanol as the reagent gas. Coelutions of compounds with the same m/z were checked using methanol-d₄. The method we developed was linear in the 10–300ng/L range of MND concentrations, with satisfactory repeatability. The detection limit was 4.3ng/L, over 3 times lower than the olfactory perception threshold of this compound (16ng/L). The suitability of this method for assaying this diketone in red wine was demonstrated by the analyzing many wines from different vintages.