Novel simple method for quantitation of nitrogen compounds in middle distillates using solid phase extraction and comprehensive two-dimensional gas chromatography

• Published in: Fuel (Guildford) Vol. 104; pp. 752 - 757
• Main Authors: Lissitsyna, K., Huertas, S., Quintero, L.C., Polo, L.M.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-02-2013; Elsevier
• Subjects: Applied sciences; Comprehensive two-dimensional gas chromatography; Crude oil, natural gas and petroleum products; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fuels; GC × GC; Middle distillates; NCD; Nitrogen chemiluminescence detector; Processing of crude oil and oils from shales and tar sands. Processes. Equipment. Refinery and treatment units; Nitrogen chemiluminescence detector; Middle distillates; Comprehensive two-dimensional gas chromatography; GC×GC; NCD; Solid phase extraction; GC x GC; Fractionation; Hydrocarbon; Nitrogen compounds; Chemiluminescence; Gas chromatography; Distillate; Pyridine; Aniline; Crude oil; Refining; Quinoline; Detection
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2012.08.054

► Identification and quantitation of N-compounds in middle distillates is achieved. ► The method is based on SPE fractionation followed by GC×GC-NCD. ► The fractionation avoids the overlapping between basic N-compounds. ► Results were compared with ASTM-4629 reference method and they closely resemble. ► The method provides a distribution of organic N-compounds in middle distillates.
Nitrogen speciation in crude oil and its fractions has become an important issue due to the undesirable effects of nitrogen compounds during important petroleum refining processes. In this work, a comprehensive two-dimensional gas chromatography method with a nitrogen chemiluminescence detector (GC×GC-NCD) was used for the speciation and quantification of nitrogen compounds in middle distillates. The developed method is based on an extraction of nitrogen compounds from the hydrocarbon matrix followed by their fractionation using solid phase extraction (SPE). Two fractions were collected thus minimizing misidentifications; the first one contained anilines, indoles and carbazoles and the second one contained pyridines, quinolines and acridines. An excellent agreement for total nitrogen content was found between the results obtained with the present method and those from the American Society for Testing Materials (ASTM) method. Good recoveries, repeatability and low detection limits (LOD), in a range from 10 to 20μgL−1, were also achieved.