CFS - Technical Information Sheets - Chemistry - Oil
Technical Information Sheets
Oils, fats and waxes are ignitable substances that are collectively referred to as 'ignitable oils' in this information sheet.
Items, such as scene debris or clothing from a suspect, are routinely collected in the investigation of a suspicious fire. These items may be examined at the laboratory for the presence of ignitable oils. Such products may have been used to set, spread or increase the intensity of a fire. The identification of such products does not necessarily indicate that the crime of arson has been committed. All laboratory results must be evaluated in the context of the fire investigation.
Analysis to determine whether or not an ignitable oil can be identified may be carried out on selected items upon request. Once items have been examined for ignitable oils, future examination for volatile ignitable liquids will not be possible. Therefore, any requests for examination to determine whether or not volatile ignitable liquids can be identified will be completed first.
When packaging items suspected of containing ignitable oils, it is vital that a protective seal is provided against loss from the container and from external contamination. Recommended packaging includes sealed glass Mason jars and specialty nylon bags. Suspected ignitable oil samples should be submitted in glass vials with foil-lined lids.
Whenever possible, samples from known sources should be collected and submitted for comparison purposes.
Sample Prep / Extraction
Items which may contain an ignitable oil will be extracted with an appropriate solvent to recover any oils that may be present.
Once prepared, solvent extracts are analyzed using Gas Chromatography-Mass Spectrometry (GC/MS) or Liquid Chromatography - Mass Spectrometry (LC-MS-MS). GC and LC are standard analytical techniques that separate the components of a sample and generate a chart known as a chromatogram. Ignitable oils are identified by their distinctive patterns in these chromatograms. Mass spectrometry assists in classifying and identifying the components of a sample. This laboratory does not determine the quantity of any identified ignitable oil in an item, as it cannot be related to the quantity of oil originally present at the scene.
Oils can be broadly categorized as being either of biological origin (plant and animal sources) or of petroleum origin. Possible contaminants and/or effects of heat from a fire may affect oils in such a way as to preclude their identification and/or classification. Oils of biological origin may not be identifiable if spoilage has occurred.
Plant and Animal Oils and Fats:
Depending on the amount and condition of the sample, it may be possible to determine the classification of plant and animal oils and fats, e.g. canola oil, corn oil, lard.
When submitted, reference ignitable oil samples may be compared with an unknown sample to determine whether or not they could share a common origin. Where no reference ignitable oil is submitted, it is only possible to report whether or not a mineral oil has been identified. It is not possible to provide information about the brand, type or grade of mineral oil, e.g. 5w30, 10w30, transmission oil, etc., at this laboratory.
An ignitable liquid that does not readily generate vapours. Examples of ignitable oils include mineral, vegetable and animal oils. Common commercial product examples include cooking oils and some lubricants.
A substance that is chemically similar to plant or animal oil but is solid or semi-solid at room temperature.
Examples include cooking oils and linseed oil.
Animal oils and fats
Examples include butter, lard, tallow, and fish oils.
Oils from petroleum sources such as motor oils, synthetic oils and baby oil.
A liquid capable of dissolving another substance.
Plant and animal-based oils and fats are composed primarily of triglycerides.
Volatile ignitable liquid
An ignitable liquid which readily generates vapours. Examples of such liquids include gasoline, lighter fluids, paint thinners, alcohols and some solvents.
Substances that are chemically similar to oils but are solid or semi-solid at room temperature. Examples of commercial products that may contain waxes include polishes, candles, crayons and cosmetics.