Unit VIII Final Project
For your final project, you will apply the scientific method approach to determine the fire cause and origin of this one- and two-family dwelling. Complte an investigative report on all the details of the fire and probable cause based upon the given information:
Time: 0900 hours
Date: November 28, 2014
Weather Conditions: Clear–38 degrees (cold wind @ 20 mph)
Type of Structure: One- and two- wooden-frame family structure
Occupants: Family of four: Husband, wife, (9) y/o male, (4) y/o female
Pictures: Click here to access the images.
Notification: At 0900 hours, you were notified by the fire dispatcher to respond to 1212 Streetman Circle on a reported structural fire that was under control and required a cause and origin investigator. Once you arrived on the scene, you were briefed by Lt. Dan Coleman, who stated that upon arrival the fire was showing out both kitchen windows and was spreading quickly to the living-room areas. The fire was then quickly extinguished and confined to the kitchen. There was noticeable burn patterns forming a large V-pattern that indicated the fire originated in the oven appliance area.
To prevent any form of spoliation, the Anytown Fire Department completed its fire suppression efforts and taped off the area for further investigation prior to any additional over hauling procedures.
Wife’s Statement: Mrs. Williams stated that she was preparing breakfast for her children when her cellular phone rang. She walked to her front porch where she became engaged with a general conversation with her friend. With bacon still cooking on the stovetop, the grease became so hot that it ignited and vertically spread into the ceiling. Once off the phone, the homeowner noticed smoke coming from the kitchen area. After investigating the kitchen, she was able to locate the burning pot and activate the 911 system as she was exiting her home for safety. The Anytown Fire Department then arrived and extinguished the fire.
You are now at the fire scene. Explain the specific details of the pre-arrival information, en-route and fire scene investigation, and interviews. Be sure to include your physical findings and any evidence that may have been collected from the fire scene. This investigative report should include all findings with a completed hypothesis of the fire.
Your report should include the following elements:
? tile page,
? abstract (one paragraph in length),
? body of the report (at least 7 50 word in length or three full pages),
? conclusion (include at the end of your report), and
? referen ce page.
The body of your report should include all seven steps of the scientific mThe body of your report should include all seven steps of the scientific method and a final hypothesis. Additionally, you are required to use at least one outside source from the Online Library(listed below). If you choose to use more than one outside source, you may use reliable sources from the Internet or your textbook.
Author: Baerncopf, Jamie; Hutches, Katherine
Publication info: Forensic Science International ; Amsterdam 244 (Nov 1, 2014): e12-20.
ProQuest document link
Abstract:
The continually-evolving field of fire debris analysis presents challenges to examiners on a regular basis. This article combines an overview of the scientific literature with novel samples that illustrate the current issues faced by fire debris examiners. Unusual liquids that contradict current classification schemes are discussed, as are complex matrices with noteworthy interferences. The matrix effects range from inherent interferences to the degradation of ignitable liquids. Finally, non-routine analyses are discussed, including the analysis of vegetable and lubricating oils and novel ignition methods. Through open discussion of complex samples and individual experiences, the problems in fire debris analysis can be overcome, resulting in the production of accurate and authoritative information.
Full text:
The area of fire debris analysis is a continually evolving field. In recent years, there have been developments by manufacturers resulting in new types of liquids that challenge classifications schemes and new materials in household items that result in complex matrix interferences. Additionally, fire debris examiners are increasingly called upon to analyze samples outside the typical ignitable liquid analysis. Some laboratories may be currently limited in their instrumental capabilities; however, these non-routine analyses are becoming more common.
Previously, this vital information has been spread easily by word-of-mouth during meetings of forensic science organizations, ranging from local to international, and from experienced examiners to new examiners within laboratories. Due to lack of funding and attrition of experienced examiners, this method of information exchange has lost its original efficacy, and information is now generally shared during occasional email exchanges with colleagues about difficult samples. An additional method of information exchange has been publication of fire debris research, which has been quite prolific. Some papers in particular have addressed individual problematic samples, liquids, or matrix effects [1-8] . This article is intended as a consolidation of the written information and cumulative experiences of several fire debris examiners in order to continue the tradition of open discourse about potentially problematic samples.
Materials and methods
All liquid samples were diluted with carbon disulfide (Fisher Scientific, Pittsburgh, PA). Matrix interference samples were extracted by passive headspace concentration [9] . Half of an activated carbon strip (Albrayco Technologies, Inc., Cromwell, CT) was suspended from the lid of each can using a magnet and paper clip. The cans were heated in an oven at approximately 65°C for 16h. After the cans were removed from the oven and allowed to cool, the strips were removed, and each was eluted with 350L of carbon disulfide.
Sample dilutions and extracts were analyzed using an Agilent 6890N GC with 5973 MS (Agilent Technologies, Santa Clara, CA) equipped with a J&W DB-1MS, 30mx250mx0.25m column (Restek Chromatography Products, Bellefonte, PA). Sample volumes of 1.0L were injected at 250°C with a split ratio of 30:1. Helium carrier gas was used at a constant flow of 0.6mL/min. The oven temperature started at 37°C (2min), ramped at 5°C/min to 120°C, and finally ramped at 12°C/min to 280°C (4min). The transfer line to the mass spectrometer was maintained at a constant 280°C, the ion source at 300°C and the MS quadropole at 150°C. The mass spectrometer was set for a full scan in electron ionization mode over an m/z range of 15.0-100.0amu prior to solvent elution and 33.0-300.0amu after solvent elution. The source was turned off during solvent elution. Each component was identified based on comparison of its mass spectrum to the National Institute of Standards and Technology mass spectral library.
Discussion
Liquids
While liquids can be some of the simplest samples analyzed by a fire debris examiner, due to the lack of matrix interferences, they can present their own challenges. Variation in petroleum product compositions and classification protocols can introduce questions about the ‘most correct’ classification of a particular liquid. It is important to determine the classification that is most representative of the submitted evidence to ensure accurate information for possible leads for investigators. As an agency with forensic laboratories across the United States, the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) is exposed to a wider range of sample variation than a city or regional laboratory, and cross-country peer reviews have demonstrated that regional differences can affect an examiner’s perception of what is considered to be within the normal range of a given class. Because of this, the importance of a broad reference collection of ignitable liquids and open communication between examiners across the country, and even internationally, cannot be overstated. Several liquids will be discussed in this section; however, this section is by no means comprehensive.
Liquids: challenges in classification
The majority of liquids and samples encountered are easily classified using the ASTM classification system [10] . However, in several cases, liquids have been encountered that are difficult to classify. These liquids may not exhibit a typical petroleum pattern or may differ in chemical content from an established classification. It is important to be aware of these liquids so that they can be correctly identified, particularly in samples complicated by matrix interferences or weathering.
An example of a product that resists classification under ASTM E1618 is Power Service Diesel Fuel Supplement (Power Service Products, Inc., Weatherford, TX). This liquid has been encountered in casework and is included in the Ignitable Liquid Reference Collection (ILRC) [11] . According to the ingredients listed by the manufacturer, the product contains “petroleum distillates and aromatic hydrocarbons,” and exposure of the neat liquid to an open flame showed that it was easily ignited. The product contains aromatic and indane components commonly found in ignitable liquids, but the total ion chromatogram (TIC) and extracted ion profiles (EIPs) do not show a recognizable petroleum pattern ( Figs. 1a, 2a, and b ). The product has a strong indane EIP in a pattern that is somewhat similar to that seen in petroleum distillates or gasoline; however, the ratios of the C2- and C3-alkylbenzenes in the aromatic EIP are not consistent with a petroleum product. This product definitely highlights the need for a flexible classification system to include a “miscellaneous” or similar category, which may not be currently included in the classification protocols of some laboratories. Without this category, an examiner may not be able to identify an ignitable liquid, even with a suitable reference. As a result, this may be misleading to an investigator who may believe that no ignitable liquids were present, rather than none could be identified. Additionally, it should be noted that the description of a product in the Material Safety Data Sheet (MSDS) or ingredient listings as a petroleum distillate does not necessarily indicate that the liquid is a petroleum distillate, only that it is likely petroleum-based.
A less extreme example of the need for a “miscellaneous” classification is TruFuel (TruSouth Oil, Shreveport, LA) (Fig. 1 b). This product contains toluene, C2-alkylbenzenes, branched alkanes similar to a light isoparaffinic product, and low abundance C4-C6n-alkanes. The presence of n-alkanes precludes classification as a light isoparaffinic product, but the lack of cyclic alkanes where normally present may complicate classification as a light petroleum distillate, in addition to the light aromatic product.
Everbrite Protective Coating (Everbrite Inc., Reno, NV) is another example of a product that may be problematic in classification as it differs from the typical aromatic product. Conventionally, aromatic products contain the same patterns of components as seen in gasoline, though the range is much more limited. Everbrite Protective Coating contains a broad range of aromatic components, including C2- to C4-alkylbenzenes, similar to the broad range in gasoline seen in the TIC and aromatic EIP ( Figs. 1c, 2c ). The indane EIP has similar features to that of gasoline at the beginning of the pattern (Fig. 2 d). As the aromatic and indane EIPs are similar to those of gasoline, Everbrite Protective Coating is potentially difficult to differentiate from gasoline. Comparing the liquids, the lack of alkane components which are present in gasoline can be used to differentiate the aromatic product. However, this difference may be difficult to discern in debris samples with strong matrix interferences, particularly given the high variability in alkane content in gasoline, which will be discussed in the following section. The accurate differentiation of these products may have significant investigative implications as it may affect what leads investigators choose to follow, so careful evaluation of chromatograms is imperative.
Liquids: gasoline
Gasoline is an ignitable liquid that is very commonly encountered and classically easy to identify. Gasoline (as it is known in the United States) is a highly refined petroleum product that is a blend of different petroleum feedstocks. However, references that show data for gasoline samples do not necessarily highlight the broad range in the composition of gasolines that is often introduced at the refinery or even gas stations [11-13] . Though the overall pattern of dominant aromatic content remains generally consistent, the alkane, polynuclear aromatic, and indane content can differ greatly. The indanes and polynuclear aromatics vary mainly in abundance, whereas the alkane content may show differences in abundance and/or pattern between gasolines. Fig. 3 shows chromatograms of two gasoline samples with distinct indane content. In analyzing neat liquids, the weak indane pattern seen in Fig. 3 d is clear, though much lower in abundance than the other gasoline sample. However, this pattern may be nearly imperceptible at a weaker concentration in debris samples. Since examiners may place emphasis on particular features or chemical content to identify gasoline, such as the indane pattern, it is important to be familiar with such variability among gasolines.
It is known that the alkane content in gasoline can vary by grade and region, and is generally accepted to be lower than aromatic content [10,13] . However, some gasolines show much reduced alkane content or the alkane content may exhibit patterns similar to a petroleum distillate or an isoparaffinic product. Fig. 4 shows the TIC and alkane EIPs for three gasolines with varying alkane content. The alkane content shown in Fig. 4 b is comparable to a distillate pattern showing n-alkanes and branching. The gasoline sample in Fig. 4 c is a higher octane and shows reduced alkane content with light and medium isoparaffinic patterns in the alkane EIP. More highly branched alkanes have a higher octane number than singly branched or straight chain alkanes and as such, may be more prevalent in premium grade gasolines [14] . A third gasoline sample displayed in Fig. 4 e and f shows another pattern of alkane content. Again, this difference in chemical content should be considered when identifying gasoline samples.
Generally the resemblance of the alkane content to a petroleum distillate in gasoline is not an issue as the strong aromatic content clearly distinguishes gasoline from a true petroleum distillate. However, with evaporation of volatile aromatic components, the chromatographic pattern may begin to resemble a heavy petroleum distillate (HPD). Fig. 5 a shows a chromatogram of a neat gasoline, with no petroleum distillate pattern visible. As the sample becomes more weathered, a Gaussian distribution of n-alkanes in the heavier region becomes apparent in addition to a strong polynuclear aromatic pattern ( Fig. 5 b). At this level of evaporation, the polynuclear aromatic content is much greater than the alkane content. Examiners who have little experience with this type of sample may be tempted to identify the two patterns separately, though that may not be the most accurate classification of the sample. When the gasoline is further weathered to dryness, analysis of the residue resembles an HPD with no indication of gasoline ( Fig. 5 c). In comparing gasoline samples between laboratories on different coasts of the United States, it has been observed that stronger heavy alkane content such as that seen in Fig. 5 c is not as prevalent on the West Coast as it may be in other parts of the country. This supports previous research that gasoline content varies by geographic location [13-15] . It should also be noted that gasoline content has been observed to change depending on the time of year [15,16] .
Based on Environmental Protection Agency (EPA) regulations, ethanol is commonly found in gasoline [17] . Ethanol is routinely blended with gasoline at ratios of up to 10%. E85 is an alternative fuel that is an approximate mixture of 85% ethanol and 15% gasoline. In the United States, a mixture of 15% ethanol and 85% gasoline, known as E15, has been recently approved for use in newer vehicles. Blender pumps offer ethanol-blended gasoline products between E15 and E85 for vehicles with suitable engine types. With these varying ethanol-blended gasoline products available, an examiner should use care when identifying a mixture of ethanol and gasoline. In a neat liquid, it may be clear that the sample is an ethanol-blended gasoline; however, debris samples pose a challenge. Additionally, liquid samples that contain gasoline as well as an aqueous layer may be problematic as ethanol is soluble in water. Ethanol identified in the aqueous layer may be a result of ethanol from gasoline equilibrating with the aqueous layer or may come from a separate source of ethanol. When reporting a mixture of ethanol and gasoline in a sample, it may be valuable to include a statement concerning alternative fuels, if such a product is suspected.
Liquids: additional issues
In compiling a reference collection of over 600 ignitable liquid and oil samples at the authors’ laboratory, important observations have been made in the composition of petroleum products. A single product may change composition over time, with different batches, or with changes in consumer needs [15,18] . For example, Fig. 6 contains the TIC for three samples of GumOut Gas Treatment (SOPUS Products, Houston, TX), collected at different times and geographic locations. Two samples were collected in California and the third was purchased in Georgia. All three samples exhibit an HPD pattern, but with different carbon ranges and abundance of branching. One sample also contains a medium aromatic product ( Fig. 6 c). STP Gas Treatment (ArmorAll/STP Products Co., Oakland, CA) is another example of a product changing composition over several years (Fig. 7 ). The STP product demonstrates different blending ratios between the HPD and aromatic components. An examiner should keep variability in product composition in mind when attempting to comment on the source of an ignitable liquid further than identifying the class. Also, as some commercial products are known to contain more than one type of petroleum product, it is important to communicate with investigators when identifying a mixture. When applicable, it may be helpful to report examples of commercial products that contain such a mixture.
Conversely, liquids from different manufacturers and applications have been shown to exhibit nearly visually indistinguishable compositions. This is commonly seen in light and medium petroleum distillates such as lighter fluids, charcoal starters and paint thinners. Fig. 8 shows an example of aviation gas and racing fuel: two products with distinct applications yet very similar compositions. Again, this underscores the care that should be taken in trying to identify information about an ignitable liquid beyond classification.
More recently, some products have been recognized as containing a petroleum product, but are advertised as being non-flammable. Fig. 1 d contains the TIC for Klean-Strip Safer Paint Thinner (W.M. Barr, Memphis, TN) which clearly shows a petroleum pattern. According to the product labeling, it contains petroleum distillates. The product labeling also noted that “neither this product nor any of its ingredients are considered to be flammable liquids by the Consumer Product Safety Commission,” and the liquid initially did not burn when exposed to a flame. After allowing the liquid to rest, two distinct layers formed and the top layer was ignitable. There are also two Lamplight Lamp Oil products listed on the ILRC as non-flammable, but again each contains a petroleum product. It seems that the description of ingredients as “non-flammable” may result from careful wording regarding the difference between flammable and combustible, but these products highlight the importance of the independence of fire investigation from ignitable liquid analysis. Ultimately, the main responsibility of the fire debris examiner is to identify the presence of an ignitable liquid if one is present, not to determine the significance of the liquid.
Matrix interferences: inherent interferences
Part of an examiner’s training often includes the analysis of common household items in burned and unburned states. It is impossible, however, to test every single product. A few products not mentioned in previous studies are discussed below.
Polyethylene has long been realized as a source of potential interference due to its degradation to n-alkanes with accompanying alkenes [15] . A more recent analysis of a variety of plastic items, however, revealed a pattern of n-alkanes as seen in the TIC of an unburned plastic grocery bag (Fig. 9 a). The major peaks are all even n-alkanes, with much lower peaks for a few odd n-alkanes and no appreciable alkenes. While this is not consistent with any known n-alkane product, it does highlight the need for pattern comparison in addition to pattern recognition as part of the standard classification process.
Of greater concern are matrices that inherently contain ignitable liquids. Flooring has been previously reported as potentially containing Isopar H [4] . Samples of other unburned plastic materials, including bubble wrap and a plastic storage bag, were analyzed and each found to contain a low but identifiable isoparaffinic product (Figs. 9 b and c). Interestingly, the bubble wrap and plastic storage bag had even n-alkane patterns similar to the plastic bag in Fig. 9 a. The plastic storage bag also had a relatively strong dodecene peak, which should indicate to an examiner that the source of the n-alkane pattern was not an ignitable liquid. Another example of an inherent ignitable liquid comes from tires. During initial fire debris training, one of the authors burned a tire and was surprised to find limonene, which is produced during the pyrolysis of polyisoprene in tires [19] . Care should be taken when reporting ignitable liquids in the presence of these types of matrices. When practical, collection of comparison samples, or samples of the same matrix of interest believed to be free of ignitable liquids, should be considered.
Another substrate known to innately contain ignitable liquids is shoes [1] . The implied importance of a finding of an ignitable liquid in shoes comes at the perception of a desired link between a scene and a suspect. The establishment of this link is potentially problematic. Shoes are known to contain toluene and may occasionally contain other ignitable liquids. More recently, unburned rain boots and walking shoes were analyzed for the National Center for Forensic Science (NCFS) Substrate Database, which is a very useful resource when evaluating matrices [20] . Gasoline was identified in both of these items. The prevalence of gasoline in shoes is not yet known; however, the possible inherent presence of gasoline or other petroleum products in shoes is important knowledge for the fire debris examiner and for all parts of the investigative chain. Conversely, even if shoes were exposed to an ignitable liquid, either through walking through a puddle of ignitable liquid or commonplace refueling activities, the resulting chromatographic pattern might be too weak for identification of an ignitable liquid [21,22] .
Matrix interferences: microbial degradation
The modern challenges in fire debris analysis do not simply consist of an increase in classification-defying ignitable liquids, but also an increased awareness of the changes that can occur to ignitable liquid residues in debris samples as a result of microbial activity.
The fire debris community is aware of the presence of microbes in soil, which has the potential to degrade petroleum products [23-26] . Degradation is seen to a greater extent in n-alkanes and monosubstituted aromatics than other components. This degradation can be rapid and can prevent identification of ignitable liquids, depending on the flexibility of laboratory protocols and availability of comparison soil samples. More recently, degradation of gasoline on moldy wood has also been reported [27] . The degradation observed was largely similar to the degradation reported in previous soil experiments. Within two weeks of spiking, the gasoline pattern was significantly altered, rendering it potentially unidentifiable by ASTM E1618 [10] .
The potential for rapid degradation highlights the need for information dissemination across the entire chain of custody. During training courses, investigators (i.e. law enforcement, fire personnel, etc.) are now commonly informed of the need for freezing or refrigeration of soil samples, but it is equally important to notify any evidence technicians who may be responsible for long-term evidence storage. This is especially true in laboratories that may suffer from backlogs due to understaffing or underfunding, where samples may not be analyzed for weeks or months after collection.
Matrix interferences: linear alkylbenezenes
Attention has recently been drawn to the potential interference of linear alkylbenzenes (LABs) in debris samples [7] . LABs with long aliphatic chains may be produced by the pyrolysis of linear alkylbenzene sulfonates (LAS), which can be found in dishwashing detergents sometimes used as an alternative to commercial foams by firefighting personnel. Other breakdown products include toluene, ethylbenzene, xylenes, indane, naphthalene and singly-substituted naphthalenes. These compounds are also target compounds common to ignitable liquids. Patterns of linear alkylbenzenes similar to the pattern of alkanes in a petroleum distillate have been observed in casework in the authors’ laboratory, possibly attributable to this phenomenon. However, none of the detergents studied by Contreras et al. resulted in a pattern consistent with an ignitable liquid. It is important to be familiar with this pattern as it may appear similar to a manufactured petroleum product, much like the pattern of decomposition products from polyethylene. Additionally, if LABs are present in a debris sample, it may be useful to contact the firefighting personnel to determine what, if any, foaming agent was used on scene and possibly obtain a sample. This is also true if limonene, another foam additive, is observed and suppression efforts are suspected to be the cause.
Non-routine samples: vegetable oils/biodiesel
The realm of what is considered ‘fire debris’ samples no longer is limited to the narrow scope of the identification of ignitable liquids, but has broadened noticeably over the last decade to include different types of examinations.
A recent addition to the spectrum of liquids potentially identified by fire debris examiners is vegetable oils, largely due to the advent of biodiesel/biodiesel blends. Biodiesel blends are mixtures of petroleum diesel and fatty acid methyl esters (FAMEs). While biodiesel is not yet widely used as a fuel for vehicles, it is slowly expanding in popularity and availability. A number of states, including Oregon, Minnesota, Washington, and Pennsylvania, have requirements that ‘standard’ diesel must contain 2 or 5% biodiesel [28] . If the percentage of biodiesel is 5% or less, however, retailers are not required to label the diesel as biodiesel [29] . This fuel is beginning to enter fire debris casework, and it is increasingly necessary to be able to recognize the presence of FAMEs as part of the ignitable liquid analysis [30,31] . It should be noted that the FAME content of the biodiesel may vary depending on the original feedstock. According to the National Biodiesel Board, the majority of biodiesel is made with soybean oil, followed by recycled cooking oils, animal fats, corn oil, and canola oil [32] .
The presence of FAMEs can potentially be identified in the standard ignitable liquid GC-MS analyses using extracted ion chromatograms (EICs) for ions such as m/z 74. It is important to note that FAMEs may be visible not only in liquid samples, but also potentially in samples analyzed by passive headspace concentration. When an HPD is identified, a quick check of the EIC for m/z 74 can screen for FAMEs, indicating a possible biodiesel blend. A more polar column, however, is necessary to achieve full resolution of the various isomers of the unsaturated fatty acids, allowing for comparison between questioned and known samples.
Additionally, vegetable oils may be relevant to an investigator in the rare instances of suspected spontaneous ignition [15,33] . In analyzing vegetable oils in these situations, it is necessary to derivatize the vegetable oils to produce FAMEs, which can then be identified by GC-MS. In debris samples, solvent extraction is required prior to derivatization. As with the FAMEs in biodiesel, a more polar column is useful for resolving the isomers of the unsaturated fatty acids, allowing a possible determination of the likelihood of spontaneous ignition
Care needs to be taken in identifying vegetable oils, however, due to the prevalence of fatty acids or fatty acid derivatives in the environment, as well as in common household products. Many household products such as lotions, makeup, and other beauty products may contain vegetable oils, but some products, such as some soaps, contain fatty acids that did not originate from vegetable oils. Human tissues and excretions, such as oils from fingerprints, are also a potential source of fatty acids [33-35] . The presence of single or multiple FAMEs in a derivatized sample does not mean that a vegetable oil is or was present. As with ignitable liquids, comparison of FAMEs content with known vegetable oils should be conducted to determine whether or not the pattern of FAMEs present suggests a vegetable oil was present. It should be noted that when a vegetable oil has experienced self-heating, the FAMEs content will not compare well to the original vegetable oil [36] .
Non-routine samples: lubricating oils
Lubricating oils and greases are perhaps a natural extension of the petroleum products already being analyzed [37] . There are several types of lubricating oils which include conventional lubricating oils (from crude oil), synthetic lubricating oils (modified petroleum components), and synthetic blends (mixture of conventional and synthetic) [38] . Lubricating oils may also contain additional components such as glycols and esters that are added to adjust the properties of the oil. Lubricating oils generally contain a large unresolved envelope of hydrocarbons and may have smaller spiking n-alkanes protruding from the envelope. Some synthetic oils have a markedly different chromatographic pattern, such as a triangular shape, better-resolved hydrocarbon peaks, or multimodal unresolved envelopes visually distinguishable from the normal, quasi-Gaussian unresolved envelopes of traditional lubricating oils.
Lubricating oils are not volatile and may not be detected using typical fire debris headspace concentration techniques. It is known that passive headspace concentration may not be suited to extract compounds above hexadecane at temperatures lower than 60°C [9] . Lubricating oils generally fall in the C18 to C40+ range, and as such are not efficiently extracted from debris samples using headspace techniques. Solvent extraction is often required for the analysis of lubricating oils in debris, with sample concentration sometimes proving necessary. Due to the destructive nature of solvent extraction, screening for lubricating oils, as well as fatty acids, is not a standard technique, but is generally considered on an individual basis depending on the case circumstances. Additionally, lubricating oils may not appear during standard ignitable liquid GC-MS analysis, depending on the temperature program used. The use of high temperature columns, such as aluminum- or polyimide-clad col
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