Using Multiple Criteria for Fingerprinting Unknown Oil Samples Having Very Similar Chemical Composition

This paper describes a case study in which a multi-criterion approach was used to fingerprinting and identifying mystery oil samples. Three unknown oil samples were received from Quebec on March 28, 2001 for chemical analysis. The main purpose of this analysis was to detemine the nature and the type of the products, detailed hydrocarbon composition of the samples, and whether these samples came from the same source. The samples were analyzed by gas chromatography with a flame ionization detector (GC-FID) and by gas chromatography coupled with mass spectrometry (GC-MS). Hydrocarbon distribution patterns of unknown oils were recognized. Multiple suites of analytes were quantified and compared. A variety of diagnostic ratios of "source-specific marker" compounds for interpreting chemical data were further determined and analyzed. The chemical fingerprinting results reveal the following: (1) These three oils are most likely a hydraulic-fluid type oil. (2) These three oils are very "pure", largely composed of saturated hydrocarbons with the total aromatics being only 4-10% of the TPH. (3) The oils are a mixture of two different hydraulic fluids. There is no clear sign indicating they had been weathered. (4) The PAH concentrations are extremely low (<10 µg/g oil) in the oil samples, while the biomarker concentration are unusually high (4700-5500 µ/g oil). (5) Three major unknown compounds in the oil samples were positively identified. They are antioxidant compounds added to oils. (6) Samples 2996 and 2997 are identical and come from the same source. (7) The sample 2998 has group hydrocarbon compositions (including the GC traces, TPH, and total saturates) very similar to samples 2996 and 2997. But, it is not identical in chemical composition to samples 2996 and 2997, and they do not come from the same source.     

Improved and Standardized Methodology for Oil Spill Fingerprinting

The existing Nordtest methodology for oil spill Identification has over the past 10 years formed an important "platform" for solving oil spill identification cases both in the Scandinavian countries as well as other countries in Europe, the USA and Canada. " Revision of the Nordtest Methodology for Oil Spill Identification " is a cooperative project between the National Oil Spill Identification laboratories in Norway, Sweden, Finland, Denmark and the Battelle Memorial Institute (Duxbury) in the USA. The goals of the project are: (1) to refine the existing Nordtest methodology into a technically more robust and defensible oil spill identification methodology with focus on determination of quantitative diagnostic indices (ratios) and (2) to adjust the revised Nordtest methodology into guidelines for the European Committee for Standardization (CEN). This paper presents the recommended methodology for the analytical oil spill identification part. The sampling techniques and handling of oil samples and background (reference) samples prior to their arrival at the environmental forensic laboratory is not covered in this paper. The recommended methodology approach is a result of documented analytical improvements and a more quantitative treatment of analytical data from gas chromatographic-flame ionization detector (GC/FID) and gas chromatographic-mass spectrometer methods (GC/MS-SIM) and the operational experiences over past few years among the participating forensic laboratories. The experience and literature in the field of oil exploration and production geochemistry have also played an important role for the recommended methodology. The results from a recent Round Robin test carried out among 12 laboratories using this new methodology are presented in a separate paper in this issue (Faksness et at ., 2002d).     

Improved and Standardized Methodology for Oil Spill Fingerprinting

The existing Nordtest methodology for oil spill Identification has over the past 10 years formed an important “platform” for solving oil spill identification cases both in the Scandinavian countries as well as other countries in Europe, the USA and Canada. “Revision of the Nordtest Methodology for Oil Spill Identification” is a cooperative project between the National Oil Spill Identification laboratories in Norway, Sweden, Finland, Denmark and the Battelle Memorial Institute (Duxbury) in the USA. The goals of the project are: (1) to refine the existing Nordtest methodology into a technically more robust and defensible oil spill identification methodology with focus on determination of quantitative diagnostic indices (ratios) and (2) to adjust the revised Nordtest methodology into guidelines for the European Committee for Standardization (CEN). This paper presents the recommended methodology for the analytical oil spill identification part. The sampling techniques and handling of oil samples and background (reference) samples prior to their arrival at the environmental forensic laboratory is not covered in this paper. The recommended methodology approach is a result of documented analytical improvements and a more quantitative treatment of analytical data from gas chromatographic-flame ionization detector (GC/FID) and gas chromatographic-mass spectrometer methods (GC/MS-SIM) and the operational experiences over past few years among the participating forensic laboratories. The experience and literature in the field of oil exploration and production geochemistry have also played an important role for the recommended methodology. The results from a recent Round Robin test carried out among 12 laboratories using this new methodology are presented in a separate paper in this issue (8).     

Chemical Characterization of Emissions from Vegetable Oil Processing and Their Contribution to Aerosol Mass Using the Organic Molecular Markers Approach

ABSTRACT

The organic fraction of aerosol emitted from a vegetable oil processing plant was studied to investigate the contribution of emissions to ambient particles in the surrounding area. Solvent-soluble particulate organic compounds emitted from the plant accounted for 10% of total suspended particles. This percentage was lower in the receptor sites (less than 6% of total aerosol mass). Nonpolar, moderate polar, polar, and acidic compounds were detected in both emitted and ambient aerosol samples. The processing and combustion of olive pits yielded a source with strong biogenic characteristics, such as the high values of the carbon preference index (CPI) for all compound classes. Polycyclic aromatic hydrocarbons (PAHs) detected in emissions were associated with both olive pits and diesel combustion. The chromatographic profile of dimethyl-phenanthrenes (DMPs) was characteristic of olive pit combustion. Organic aerosols collected in two receptor sites provided a different pattern.

The significant contribution of vehicular emissions was identified by CPI values (~1) of n-alkanes and the presence of the unresolved complex mixture (UCM). In addition, PAH concentration diagnostic ratios indicated that emissions from catalyst and noncatalyst automobiles and heavy trucks were significant. The strong even-to-odd predominance of n-alkanols, n-alkanoic acids, and their salts indicated the contribution of a source with biogenic characteristics. However, the profile of DMPs at receptor sites was similar to that observed for diesel particulates. These differences indicated that the contribution of vegetable oil processing emissions to the atmosphere was negligible.