title: Gas chromatographic/mass spectrometric determination of 3-methoxy-1,2-propanediol and cyclic diglycerols, by-products of technical glycerol, in wine: interlaboratory study.
abstract: The aim of the present study was to provide the official wine control authorities with an internationally validated method for the determination of 3-methoxy-1,2-propanediol (3-MPD) and cyclic diglycerols (CycDs)-both of which are recognized as impurities of technical glycerol-in different types of wine. Because glycerol gives a sweet flavor to wine and contributes to its full-body taste, an economic incentive is to add glycerol to a wine to mask its poor quality. Furthermore, it is known that glycerol, depending on whether it is produced from triglycerides or petrochemicals, may contain considerable amounts of 3-MPD in the first case or CycDs in the second. However, because these compounds are not natural wine components, it is possible to detect glycerol added to wine illegally by determining the above-mentioned by-products. To this end, one of the published methods was adopted, modified, and tested in a collaborative study. The method is based on gas chromatographic/mass spectrometric analysis of diethyl ether extracts after salting out with potassium carbonate. The interlaboratory study for the determination of 3-MPD and CycDs in wine was performed in 11 laboratories in 4 countries. Wine samples were prepared and sent to participants as 5 blind duplicate test materials and 1 single test material. The concentrations covered ranges of 0.1-0.8 mg/L for 3-MPD and 0.5-1.5 mg/L for CycDs. The precision of the method was within the range predicted by the Horwitz equation. HORRAT values obtained for 3-MPD ranged from 0.8 to 1.7, and those obtained for CycDs ranged from 0.9 to 1.3. Average recoveries were 104 and 109%, respectively.
authors.affiliation: Bundesinstitut für Risikobewertung (BfR), PO Box 1033, D-14195 Berlin, Germany. c.fauhl@bfr.bund.de
authors.forename: Carsten
authors.initials: C
authors.lastname: Fauhl
authors.forename: Reiner
authors.initials: R
authors.lastname: Wittkowski
authors.forename: Janice
authors.initials: J
authors.lastname: Lofthouse
authors.forename: Simon
authors.initials: S
authors.lastname: Hird
authors.forename: Paul
authors.initials: P
authors.lastname: Brereton
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Versini
authors.forename: Michele
authors.initials: M
authors.lastname: Lees
authors.forename: Claude
authors.initials: C
authors.lastname: Guillou
mesh_terms: D004075:Diglycerides / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry; D005995:Glyceryl Ethers / Q000032:analysis*; D014920:Wine / Q000032:analysis*
chemical_list: D004075:Diglycerides; D005995:Glyceryl Ethers; C058902:1-O-methylglycerol