title: Analysis of the volatile organic matter of engine piston deposits by direct sample introduction thermal desorption gas chromatography/mass spectrometry.
abstract: This article establishes an alternative method for the characterization of volatiles organic matter (VOM) contained in deposits of the piston first ring grooves of diesel engines using a ChromatoProbe direct sample introduction (DSI) device coupled to gas chromatography/mass spectrometry (GC/MS) analysis. The addition of an organic solvent during thermal desorption leads to an efficient extraction and a good chromatographic separation of extracted products. The method was optimized investigating the effects of several solvents, the volume added to the solid sample, and temperature programming of the ChromatoProbe DSI device. The best results for thermal desorption were found using toluene as an extraction solvent and heating the programmable temperature injector from room temperature to 300 degrees C with a temperature step of 105 degrees C. With the use of the optimized thermal desorption conditions, several components have been positively identified in the volatile fraction of the deposits: aromatics, antioxidants, and antioxidant degradation products. Moreover, this work highlighted the presence of diesel fuel in the VOM of the piston deposits and gave new facts on the absence of the role of diesel fuel in the deposit formation process. Most importantly, it opens the possibility of quickly performing the analysis of deposits with small amounts of samples while having a good separation of the volatiles.
authors.affiliation: Ecole Polytechnique, Laboratoire des Mécanismes Reactionnels, CNRS, 91128 Palaiseau Cedex, France.
authors.forename: M
authors.initials: M
authors.lastname: Diaby
authors.forename: S
authors.initials: S
authors.lastname: Kinani
authors.forename: C
authors.initials: C
authors.lastname: Genty
authors.forename: S
authors.initials: S
authors.lastname: Bouchonnet
authors.forename: M
authors.initials: M
authors.lastname: Sablier
authors.forename: A
authors.initials: A
authors.lastname: Le Negrate
authors.forename: M
authors.initials: M
authors.lastname: El Fassi