- Email: [email protected]
Substrate interferences in identifying flammable liquids in food, environmental and biological samples: case studies
Science and Justice 55 (2015) 176–180
Contents lists available at ScienceDirect
Science and Justice journal homepage: www.elsevier.com/locate/scijus
Case review
Substrate interferences in identifying flammable liquids in food, environmental and biological samples: case studies Rafal Borusiewicz ⁎ Institute of Forensic Research, Westerplatte 9, 31-033 Krakow, Poland
a r t i c l e
i n f o
Article history: Received 26 June 2014 Received in revised form 15 September 2014 Accepted 5 December 2014 Keywords: Forensic science Ignitable liquids Fire debris analysis Substrate interferences Passive adsorption Adsorption tubes
a b s t r a c t The analysis of samples for traces of ignitable liquids is most often connected with suspected arson cases. In such cases, samples taken from the point of origin of the fire are analyzed for the presence of ignitable liquids. However, sometimes, in cases not connected with arson, there is a need to detect and identify traces of ignitable liquids. Three examples of such cases are given in this paper. Aqueous samples (polluted water, juice and blood) were analyzed using a procedure routinely used in the analyses of fire debris. The procedure consists of passive adsorption of volatile organic compounds on Tenax, followed by thermal desorption and chromatographic analysis. Results showed that analysis of such untypical samples may be connected with unusual matrix effects, not frequently encountered in fire debris samples. © 2014 The Chartered Society of Forensic Sciences. Published by Elsevier Ireland Ltd. All rights reserved.
1. Introduction In forensic laboratories, the analysis of various materials to detect traces of ignitable liquid residues is most often connected with cases of fires when arson is suspected. In such cases, sample material may vary to a large degree. Materials most often encountered are pieces of furniture, fabrics, plastics, wood, soil, paper, and concrete. These materials may be charred to various degrees and/or drenched with water that was used to extinguish the fire. Because the ignitable liquids are composed of volatile organic compounds, the chemical analysis consists of separating such compounds from the sample material. This usually occurs by passive adsorption from the headspace of the sample followed by desorption and GC-MS analysis. One of the difficulties connected with this analysis is that some volatile compounds may originate from the sample material itself (substrate background products) or be created as a product of pyrolysis or incomplete combustion of this material. Starting from the late 1960s, numerous studies dealing with this problem were conducted and their results published. An interesting and extensive review of these papers for the period 1968–2007 is available in the books [1,2]. This problem was also investigated in more recent research [3–6]. All of the aforementioned papers are focused on interferences encountered during the analysis of fire debris samples. However, it is sometimes requested that samples from non-fire cases are analyzed to
⁎ Tel.: +48 126185785; fax: +48 124223850. E-mail address: [email protected].
determine if traces of ignitable liquids are present. During such analyses, similar methods used during fire-related cases may be employed; however, atypical sample materials may result in unusual matrix effects. The purpose of this paper is to present three such cases: the analysis of water from a polluted well, the analysis of juice suspected of being poisoned, and the analysis of blood taken from the corpse of a boy exposed to gasoline fumes. 2. Material and methods Samples were analyzed by passive adsorption of volatile substances from the headspace with subsequent GC-MS analysis according to the analytical procedure routinely used for fire debris analysis. However, as the samples in the described cases were liquid, Erlenmeyer flasks were used as the containers during the adsorption stage instead of the gas-tight “fire debris” bags (Ampac, St. Louis Park, MN, USA), which are usually utilised. The analytical procedure presents itself as follows: samples were placed in the Erlenmeyer flasks with ground glass joints. Two adsorption tubes containing Tenax TA (Perkin Elmer, Waltham, MA, USA) were suspended in the headspace above the samples. Flasks were tightly closed with glass stoppers and, for safety reasons, additionally packed into polyamide bags (BVDA Security Bag, BVDA International BV, Haarlem, The Netherlands), and then closed tightly with cable ties. During the adsorption process, samples were placed in the laboratory oven at 80 °C, for 16 h (overnight). Adsorbed analytes were thermally desorbed using the Automated Thermal Desorber (Turbo Matrix ATD; Perkin Elmer) and analyzed using a gas chromatograph with a mass spectrometer (Auto System XL and Turbo Mass
http://dx.doi.org/10.1016/j.scijus.2014.12.001 1355-0306/© 2014 The Chartered Society of Forensic Sciences. Published by Elsevier Ireland Ltd. All rights reserved.
R. Borusiewicz / Science and Justice 55 (2015) 176–180
Gold; Perkin Elmer). The chromatograph was equipped with a DB5-MS UI column (30 m, id 0.25 mm, film 0.5 μm; J&W Scientific, Folsom, CA). Analyses were conducted using the following temperature program: 40 °C hold for 10 min; increase 7 °C⁄min to 120 °C; increase 15 °C⁄min to 300 °C; 300 °C and held for 5 min. For each of the analyzed samples, two adsorption tubes were used and two chromatograms were obtained. As the chromatograms were always consistent, only exemplary ones are presented in the figures. 3. Case reports 3.1. Case 1: Contaminated water Users of a well complained about foul-smelling water. Two samples of water were collected in glass jars and sent for analysis. As the smell of the samples resembled the odour of petroleum products, they were analyzed for traces of ignitable liquids. For each of the samples, the results were different. In one sample, a large amount of heavy petroleum distillate (HPD), namely kerosene, was detected. In the second sample, traces of aromatic compounds were detected. The composition was similar to gasoline, but without the most volatile compounds (Fig. 1). Information was obtained stating that although both samples of water came from the same well, one was taken directly from the well (the sample in which kerosene was detected) while the other sample (with traces of aromatics) was taken from the tap. The main components of petroleum distillates are aliphatic hydrocarbons but they also contain some amounts of aromatics. Aromatic hydrocarbons are more polar than aliphatic hydrocarbons and therefore
177
their solubility in water is higher [7,8]. It was important to determine if these differences were responsible for the obtained results, i.e., if detectable amounts of aromatics from kerosene poured into the well could dissolve in water creating gasoline-like patterns in the sample taken from the tap. To determine this, an experiment was conducted: 100 cm3 of distilled water was placed in a separation funnel and 1.5 cm3 of kerosene was added. The funnel was vigorously shaken and left to settle for 16 h. After, 50 cm3 of the water phase was separated. The comparative sample was prepared by spiking 50 cm3 of distilled water with 2 μl of kerosene. A total of 50 cm3 of distilled water constituted a blank sample. Volatile compounds were adsorbed from the headspace of the samples and analyzed according to the procedure described above. The chromatogram obtained for the spiked sample (Fig. 2, chromatogram 1) was obviously exactly the same as it would be for the pure kerosene because, in percentages, the aqueous solubility of both alkanes and aromatics is very low and this phenomenon cannot visibly change the profile of kerosene. For instance, the solubility of heptane is 0.0003% and for toluene it is 0.0531% [7]. Nonetheless, the aqueous solubility of aromatics is many times higher than for aliphatic hydrocarbons. This explains the results obtained for the sample of water taken from the separation funnel (Fig. 2, chromatogram 2) as this water had been in contact with comparatively high amounts of kerosene. For this sample, the ratio of aromatic to aliphatic compounds was much higher than for the water spiked with kerosene. On the basis of this result, it was concluded that the well was contaminated with a large amount of kerosene, which was detected in a sample taken directly from the well (i.e., from the surface). Aromatics
Fig. 1. Analysis of the contaminated water from the well. Chromatogram 1: sample taken directly from the well. On the chromatogram, a characteristic cluster of unresolved peaks of alkanes is present. The volatility range of detected alkanes is typical for kerosene. Chromatogram 2: sample taken from the tap. 1, toluene; 2, ethylbenzene; 3, p,m-xylene; 4, o-xylene; 5, C3 alkylbenzenes; 6, indane; 7, C4 alkylbenzenes; 8, naphthalene.
178
R. Borusiewicz / Science and Justice 55 (2015) 176–180
Fig. 2. Result of experiments concerning the solubility of aromatic compounds from petroleum in water. Chromatogram 1: 50 cm3 of distilled water spiked with 2 μl of kerosene. Alkanes with characteristic Gaussian distribution are present. Chromatogram 2: water phase that had been in contact with kerosene and was separated using a separatory funnel. Intensive signals of aromatic compounds are present: 1, benzene; 2, toluene; 3, ethylbenzene; 4, p,m-xylene; 5, o-xylene; 6, C3 alkylbenzenes; 7, indane; 8, C4 alkylbenzenes; 9, naphthalene; 10, 2-methylnaphtalene; 11, 1-methylnaphtalene.
of a composition similar to evaporated gasoline, which was detected in the tap water (i.e., water sampled from the depth of the well) are in fact components of kerosene dissolved in the water and not traces of gasoline. 3.2. Case 2: Poisoned beverage A man claiming that his wife was trying to poison him asked the police to secure a carton of juice suspected of being tampered with. This product was sent to be analyzed for the presence of any substances different from the regular ingredients of the juice and, if such compounds were found, to determine if they are toxic and could be dangerous, considering the concentration and total amount. During the initial inspection of the sample, it was found that the smell of the investigated juice was different from what was normal and resembled the odour of some solvents. In addition, pieces of mould were found in the juice. A 5 ml sample was taken and analyzed for the presence of volatile organic compounds. As juice naturally contains some volatile organic compounds responsible for its taste and aroma, juice of the same brand was purchased and analyzed as the comparative sample. Chromatograms obtained for the case and comparative sample of juice are presented in Fig. 3. As can be seen, the profiles of volatile compounds for both samples are different. In the case sample, there are numerous additional compounds, which can be divided into two groups: alcohols and aromatics. Although alcohols were not present in the comparative sample, they were considered to be natural ingredients
of the case sample. Alcohols may be created as the result of microbial action [9,10] and evidence of such action (pieces of mould) was visible. Therefore, only aromatic compounds were considered to be foreign for the sample. According to the ASTM classification system [11], ignitable liquids consisting of a mixture of aromatic products similar to the mixture detected in the sample in question, belong to the class “medium aromatic products” and are used, inter alia as insecticide vehicles. This information suggests that some insecticide could have been used in an attempted poisoning. A subsequent analysis conducted by the toxicology section confirmed the presence of a synthetic pyrethroid: deltamethrin. 3.3. Case 3: Blood On a Christmas eve morning, a 15-year-old boy was found dead by his parents. The child was sitting on a motorcycle in the garage with his face near the open inlet of the fuel tank. The boy suffered from asthma and was being treated for this condition. No signs of any physical injuries were found during the autopsy. Samples of tissue, including two samples of blood from the heart, were taken to be analyzed for drugs and poisons; none of which were detected. A fresh sample of blood (~4 ml), containing sodium fluoride as a preservative, was transferred to an Erlenmeyer flask and analyzed according to the previously described procedure. An empty Erlenmeyer flask was used as a blank sample. A chromatogram obtained as a result of the blood analysis is presented in Fig. 4. Although the volume of the sample was comparatively small, a
R. Borusiewicz / Science and Justice 55 (2015) 176–180
179
Fig. 3. Chromatogram 1: result of the analysis of the juice in question. Chromatogram 2: result of the analysis of the comparative sample of juice. In the questioned sample, the following compounds, not present in the comparative sample, were identified: 1, propanol; 2, isomers of butanol; 3, isomers of methyl butanol; 4, hexanol; 5, o-xylene; 6, C3 alkylbenzenes (marked with white dots); 7, indane; 8, C4 alkylbenzenes (marked with black dots).
mixture of volatile organic compounds was easily detectable. These compounds were identified as components of gasoline although their relative ratios were considerably changed. When compared to the
normal profile of gasoline, the analyzed sample exhibited a relatively high amount of volatile, polar compounds (ethyl tert-butyl ether, benzene and toluene) and relatively low amounts of less volatile
Fig. 4. Chromatogram obtained as a result of the analysis of a 4 ml sample of blood. 1, ETBE; 2, benzene; 3, heptane; 4, toluene; 5, ethylbenzene; 6, p,m-xylene; 7, o-xylene; 8, C3 alkylbenzenes; 9, indane; 10, C4 alkylbenzenes; 11, naphthalene.
180
R. Borusiewicz / Science and Justice 55 (2015) 176–180
components of gasoline [12]. Such a change in profile is contrary to the one usually noticed for fire debris samples, where the content of more volatile compounds is decreased because of their faster evaporation. This interesting effect may be explained by the route of exposure (inhalation) and the polarity of body fluids. The more volatile compounds evaporated faster, thus the amount in inhaled vapours was higher and the more polar compounds dissolved in body fluids more effectively. For the same reason, amounts of the heaviest components are diminished. The results of the analysis indicated that the boy inhaled gasoline fumes and supported the hypothesis that inhaling the gasoline fumes was the cause of his death. 4. Discussion The results from the analyses of the presented cases allowed investigators to conclude forensic investigations. Furthermore, the information presented demonstrates that the analytical procedure routinely used to analyze fire debris can also be used to analyze other kinds of samples to detect traces of ignitable liquids. The important thing to recognize is that unusual material samples may result in unusual matrix effects, such as those encountered in the presented cases. The interpretation of analyzed results of non-typical samples requires special care and caution.
References [1] E. Stauffer, Source of interference in fire debris analysis, in: N. Nid Daeid (Ed.), Fire Investigation, CRC Press LLC, Boca Raton, 2004, pp. 191–226. [2] E. Stauffer, J.A. Dolan, R. Newman, Fire Debris Analysis, Academic Press, Burlington, 2008. [3] J.M. Baerncopf, V.L. McGuffin, R.W. Smith, Association of ignitable liquid residues to neat ignitable liquids in the presence of matrix interferences using chemometric procedures, J. Forensic Sci. 56 (1) (2011) 70–81. [4] P.M.L. Sandercock, Preparation of pyrolysis reference samples: evaluation of a standard method using a tube furnace, J. Forensic Sci. 53 (3) (2011) 738–743. [5] K.R. Prather, V.L. McGuffin, R.W. Smith, Effect of evaporation and matrix interferences on the association of simulated ignitable liquid residues to the corresponding liquid standard, Forensic Sci. Int. 222 (2012) 242–251. [6] K.R. Pratcher, S.E. Towner, V.L. McGuffin, R.W. Smith, Effect of substrate interferences from high-density polyethylene on association of simulated ignitable liquid residues with the corresponding liquid, J. Forensic Sci. 59 (1) (2014) 52–60. [7] CRC Handbook of Chemistry and PhysicsInternet Version 2005, http://www. hbcpnetbase.com in: D.R. Lide (Ed.), CRC Press, Boca Raton, FL, 2005. [8] L.R. Snyder, Classification of the solvent properties of common liquids, J. Chromatogr. A 92 (2) (1974) 223–230. [9] E.I. Lan, J.C. Liao, Microbial synthesis of n-butanol, isobutanol, and other higher alcohols from diverse resources, Bioresour. Technol. 135 (2013) 339–349. [10] Y.S. Jang, A. Malaviya, C. Cho, J. Lee, S.Y. Lee, Butanol production from renewable biomass by clostridia, Bioresour. Technol. 123 (2012) 653–663. [11] ASTM Standard E1618-2011, Standard Test Method for Ignitable Liquid Residues in Extracts from Fire Debris Samples by Gas Chromatography-Mass Spectrometry, ASTM International, West Conshohocken, PA, 2011. [12] R. Newman, G. Gilbert, K. Lothridge, GC-MS Guide to Ignitable Liquids, CRC Press, Boca Raton, 1998.
Contents lists available at ScienceDirect
Science and Justice journal homepage: www.elsevier.com/locate/scijus
Case review
Substrate interferences in identifying flammable liquids in food, environmental and biological samples: case studies Rafal Borusiewicz ⁎ Institute of Forensic Research, Westerplatte 9, 31-033 Krakow, Poland
a r t i c l e
i n f o
Article history: Received 26 June 2014 Received in revised form 15 September 2014 Accepted 5 December 2014 Keywords: Forensic science Ignitable liquids Fire debris analysis Substrate interferences Passive adsorption Adsorption tubes
a b s t r a c t The analysis of samples for traces of ignitable liquids is most often connected with suspected arson cases. In such cases, samples taken from the point of origin of the fire are analyzed for the presence of ignitable liquids. However, sometimes, in cases not connected with arson, there is a need to detect and identify traces of ignitable liquids. Three examples of such cases are given in this paper. Aqueous samples (polluted water, juice and blood) were analyzed using a procedure routinely used in the analyses of fire debris. The procedure consists of passive adsorption of volatile organic compounds on Tenax, followed by thermal desorption and chromatographic analysis. Results showed that analysis of such untypical samples may be connected with unusual matrix effects, not frequently encountered in fire debris samples. © 2014 The Chartered Society of Forensic Sciences. Published by Elsevier Ireland Ltd. All rights reserved.
1. Introduction In forensic laboratories, the analysis of various materials to detect traces of ignitable liquid residues is most often connected with cases of fires when arson is suspected. In such cases, sample material may vary to a large degree. Materials most often encountered are pieces of furniture, fabrics, plastics, wood, soil, paper, and concrete. These materials may be charred to various degrees and/or drenched with water that was used to extinguish the fire. Because the ignitable liquids are composed of volatile organic compounds, the chemical analysis consists of separating such compounds from the sample material. This usually occurs by passive adsorption from the headspace of the sample followed by desorption and GC-MS analysis. One of the difficulties connected with this analysis is that some volatile compounds may originate from the sample material itself (substrate background products) or be created as a product of pyrolysis or incomplete combustion of this material. Starting from the late 1960s, numerous studies dealing with this problem were conducted and their results published. An interesting and extensive review of these papers for the period 1968–2007 is available in the books [1,2]. This problem was also investigated in more recent research [3–6]. All of the aforementioned papers are focused on interferences encountered during the analysis of fire debris samples. However, it is sometimes requested that samples from non-fire cases are analyzed to
⁎ Tel.: +48 126185785; fax: +48 124223850. E-mail address: [email protected].
determine if traces of ignitable liquids are present. During such analyses, similar methods used during fire-related cases may be employed; however, atypical sample materials may result in unusual matrix effects. The purpose of this paper is to present three such cases: the analysis of water from a polluted well, the analysis of juice suspected of being poisoned, and the analysis of blood taken from the corpse of a boy exposed to gasoline fumes. 2. Material and methods Samples were analyzed by passive adsorption of volatile substances from the headspace with subsequent GC-MS analysis according to the analytical procedure routinely used for fire debris analysis. However, as the samples in the described cases were liquid, Erlenmeyer flasks were used as the containers during the adsorption stage instead of the gas-tight “fire debris” bags (Ampac, St. Louis Park, MN, USA), which are usually utilised. The analytical procedure presents itself as follows: samples were placed in the Erlenmeyer flasks with ground glass joints. Two adsorption tubes containing Tenax TA (Perkin Elmer, Waltham, MA, USA) were suspended in the headspace above the samples. Flasks were tightly closed with glass stoppers and, for safety reasons, additionally packed into polyamide bags (BVDA Security Bag, BVDA International BV, Haarlem, The Netherlands), and then closed tightly with cable ties. During the adsorption process, samples were placed in the laboratory oven at 80 °C, for 16 h (overnight). Adsorbed analytes were thermally desorbed using the Automated Thermal Desorber (Turbo Matrix ATD; Perkin Elmer) and analyzed using a gas chromatograph with a mass spectrometer (Auto System XL and Turbo Mass
http://dx.doi.org/10.1016/j.scijus.2014.12.001 1355-0306/© 2014 The Chartered Society of Forensic Sciences. Published by Elsevier Ireland Ltd. All rights reserved.
R. Borusiewicz / Science and Justice 55 (2015) 176–180
Gold; Perkin Elmer). The chromatograph was equipped with a DB5-MS UI column (30 m, id 0.25 mm, film 0.5 μm; J&W Scientific, Folsom, CA). Analyses were conducted using the following temperature program: 40 °C hold for 10 min; increase 7 °C⁄min to 120 °C; increase 15 °C⁄min to 300 °C; 300 °C and held for 5 min. For each of the analyzed samples, two adsorption tubes were used and two chromatograms were obtained. As the chromatograms were always consistent, only exemplary ones are presented in the figures. 3. Case reports 3.1. Case 1: Contaminated water Users of a well complained about foul-smelling water. Two samples of water were collected in glass jars and sent for analysis. As the smell of the samples resembled the odour of petroleum products, they were analyzed for traces of ignitable liquids. For each of the samples, the results were different. In one sample, a large amount of heavy petroleum distillate (HPD), namely kerosene, was detected. In the second sample, traces of aromatic compounds were detected. The composition was similar to gasoline, but without the most volatile compounds (Fig. 1). Information was obtained stating that although both samples of water came from the same well, one was taken directly from the well (the sample in which kerosene was detected) while the other sample (with traces of aromatics) was taken from the tap. The main components of petroleum distillates are aliphatic hydrocarbons but they also contain some amounts of aromatics. Aromatic hydrocarbons are more polar than aliphatic hydrocarbons and therefore
177
their solubility in water is higher [7,8]. It was important to determine if these differences were responsible for the obtained results, i.e., if detectable amounts of aromatics from kerosene poured into the well could dissolve in water creating gasoline-like patterns in the sample taken from the tap. To determine this, an experiment was conducted: 100 cm3 of distilled water was placed in a separation funnel and 1.5 cm3 of kerosene was added. The funnel was vigorously shaken and left to settle for 16 h. After, 50 cm3 of the water phase was separated. The comparative sample was prepared by spiking 50 cm3 of distilled water with 2 μl of kerosene. A total of 50 cm3 of distilled water constituted a blank sample. Volatile compounds were adsorbed from the headspace of the samples and analyzed according to the procedure described above. The chromatogram obtained for the spiked sample (Fig. 2, chromatogram 1) was obviously exactly the same as it would be for the pure kerosene because, in percentages, the aqueous solubility of both alkanes and aromatics is very low and this phenomenon cannot visibly change the profile of kerosene. For instance, the solubility of heptane is 0.0003% and for toluene it is 0.0531% [7]. Nonetheless, the aqueous solubility of aromatics is many times higher than for aliphatic hydrocarbons. This explains the results obtained for the sample of water taken from the separation funnel (Fig. 2, chromatogram 2) as this water had been in contact with comparatively high amounts of kerosene. For this sample, the ratio of aromatic to aliphatic compounds was much higher than for the water spiked with kerosene. On the basis of this result, it was concluded that the well was contaminated with a large amount of kerosene, which was detected in a sample taken directly from the well (i.e., from the surface). Aromatics
Fig. 1. Analysis of the contaminated water from the well. Chromatogram 1: sample taken directly from the well. On the chromatogram, a characteristic cluster of unresolved peaks of alkanes is present. The volatility range of detected alkanes is typical for kerosene. Chromatogram 2: sample taken from the tap. 1, toluene; 2, ethylbenzene; 3, p,m-xylene; 4, o-xylene; 5, C3 alkylbenzenes; 6, indane; 7, C4 alkylbenzenes; 8, naphthalene.
178
R. Borusiewicz / Science and Justice 55 (2015) 176–180
Fig. 2. Result of experiments concerning the solubility of aromatic compounds from petroleum in water. Chromatogram 1: 50 cm3 of distilled water spiked with 2 μl of kerosene. Alkanes with characteristic Gaussian distribution are present. Chromatogram 2: water phase that had been in contact with kerosene and was separated using a separatory funnel. Intensive signals of aromatic compounds are present: 1, benzene; 2, toluene; 3, ethylbenzene; 4, p,m-xylene; 5, o-xylene; 6, C3 alkylbenzenes; 7, indane; 8, C4 alkylbenzenes; 9, naphthalene; 10, 2-methylnaphtalene; 11, 1-methylnaphtalene.
of a composition similar to evaporated gasoline, which was detected in the tap water (i.e., water sampled from the depth of the well) are in fact components of kerosene dissolved in the water and not traces of gasoline. 3.2. Case 2: Poisoned beverage A man claiming that his wife was trying to poison him asked the police to secure a carton of juice suspected of being tampered with. This product was sent to be analyzed for the presence of any substances different from the regular ingredients of the juice and, if such compounds were found, to determine if they are toxic and could be dangerous, considering the concentration and total amount. During the initial inspection of the sample, it was found that the smell of the investigated juice was different from what was normal and resembled the odour of some solvents. In addition, pieces of mould were found in the juice. A 5 ml sample was taken and analyzed for the presence of volatile organic compounds. As juice naturally contains some volatile organic compounds responsible for its taste and aroma, juice of the same brand was purchased and analyzed as the comparative sample. Chromatograms obtained for the case and comparative sample of juice are presented in Fig. 3. As can be seen, the profiles of volatile compounds for both samples are different. In the case sample, there are numerous additional compounds, which can be divided into two groups: alcohols and aromatics. Although alcohols were not present in the comparative sample, they were considered to be natural ingredients
of the case sample. Alcohols may be created as the result of microbial action [9,10] and evidence of such action (pieces of mould) was visible. Therefore, only aromatic compounds were considered to be foreign for the sample. According to the ASTM classification system [11], ignitable liquids consisting of a mixture of aromatic products similar to the mixture detected in the sample in question, belong to the class “medium aromatic products” and are used, inter alia as insecticide vehicles. This information suggests that some insecticide could have been used in an attempted poisoning. A subsequent analysis conducted by the toxicology section confirmed the presence of a synthetic pyrethroid: deltamethrin. 3.3. Case 3: Blood On a Christmas eve morning, a 15-year-old boy was found dead by his parents. The child was sitting on a motorcycle in the garage with his face near the open inlet of the fuel tank. The boy suffered from asthma and was being treated for this condition. No signs of any physical injuries were found during the autopsy. Samples of tissue, including two samples of blood from the heart, were taken to be analyzed for drugs and poisons; none of which were detected. A fresh sample of blood (~4 ml), containing sodium fluoride as a preservative, was transferred to an Erlenmeyer flask and analyzed according to the previously described procedure. An empty Erlenmeyer flask was used as a blank sample. A chromatogram obtained as a result of the blood analysis is presented in Fig. 4. Although the volume of the sample was comparatively small, a
R. Borusiewicz / Science and Justice 55 (2015) 176–180
179
Fig. 3. Chromatogram 1: result of the analysis of the juice in question. Chromatogram 2: result of the analysis of the comparative sample of juice. In the questioned sample, the following compounds, not present in the comparative sample, were identified: 1, propanol; 2, isomers of butanol; 3, isomers of methyl butanol; 4, hexanol; 5, o-xylene; 6, C3 alkylbenzenes (marked with white dots); 7, indane; 8, C4 alkylbenzenes (marked with black dots).
mixture of volatile organic compounds was easily detectable. These compounds were identified as components of gasoline although their relative ratios were considerably changed. When compared to the
normal profile of gasoline, the analyzed sample exhibited a relatively high amount of volatile, polar compounds (ethyl tert-butyl ether, benzene and toluene) and relatively low amounts of less volatile
Fig. 4. Chromatogram obtained as a result of the analysis of a 4 ml sample of blood. 1, ETBE; 2, benzene; 3, heptane; 4, toluene; 5, ethylbenzene; 6, p,m-xylene; 7, o-xylene; 8, C3 alkylbenzenes; 9, indane; 10, C4 alkylbenzenes; 11, naphthalene.
180
R. Borusiewicz / Science and Justice 55 (2015) 176–180
components of gasoline [12]. Such a change in profile is contrary to the one usually noticed for fire debris samples, where the content of more volatile compounds is decreased because of their faster evaporation. This interesting effect may be explained by the route of exposure (inhalation) and the polarity of body fluids. The more volatile compounds evaporated faster, thus the amount in inhaled vapours was higher and the more polar compounds dissolved in body fluids more effectively. For the same reason, amounts of the heaviest components are diminished. The results of the analysis indicated that the boy inhaled gasoline fumes and supported the hypothesis that inhaling the gasoline fumes was the cause of his death. 4. Discussion The results from the analyses of the presented cases allowed investigators to conclude forensic investigations. Furthermore, the information presented demonstrates that the analytical procedure routinely used to analyze fire debris can also be used to analyze other kinds of samples to detect traces of ignitable liquids. The important thing to recognize is that unusual material samples may result in unusual matrix effects, such as those encountered in the presented cases. The interpretation of analyzed results of non-typical samples requires special care and caution.
References [1] E. Stauffer, Source of interference in fire debris analysis, in: N. Nid Daeid (Ed.), Fire Investigation, CRC Press LLC, Boca Raton, 2004, pp. 191–226. [2] E. Stauffer, J.A. Dolan, R. Newman, Fire Debris Analysis, Academic Press, Burlington, 2008. [3] J.M. Baerncopf, V.L. McGuffin, R.W. Smith, Association of ignitable liquid residues to neat ignitable liquids in the presence of matrix interferences using chemometric procedures, J. Forensic Sci. 56 (1) (2011) 70–81. [4] P.M.L. Sandercock, Preparation of pyrolysis reference samples: evaluation of a standard method using a tube furnace, J. Forensic Sci. 53 (3) (2011) 738–743. [5] K.R. Prather, V.L. McGuffin, R.W. Smith, Effect of evaporation and matrix interferences on the association of simulated ignitable liquid residues to the corresponding liquid standard, Forensic Sci. Int. 222 (2012) 242–251. [6] K.R. Pratcher, S.E. Towner, V.L. McGuffin, R.W. Smith, Effect of substrate interferences from high-density polyethylene on association of simulated ignitable liquid residues with the corresponding liquid, J. Forensic Sci. 59 (1) (2014) 52–60. [7] CRC Handbook of Chemistry and PhysicsInternet Version 2005, http://www. hbcpnetbase.com in: D.R. Lide (Ed.), CRC Press, Boca Raton, FL, 2005. [8] L.R. Snyder, Classification of the solvent properties of common liquids, J. Chromatogr. A 92 (2) (1974) 223–230. [9] E.I. Lan, J.C. Liao, Microbial synthesis of n-butanol, isobutanol, and other higher alcohols from diverse resources, Bioresour. Technol. 135 (2013) 339–349. [10] Y.S. Jang, A. Malaviya, C. Cho, J. Lee, S.Y. Lee, Butanol production from renewable biomass by clostridia, Bioresour. Technol. 123 (2012) 653–663. [11] ASTM Standard E1618-2011, Standard Test Method for Ignitable Liquid Residues in Extracts from Fire Debris Samples by Gas Chromatography-Mass Spectrometry, ASTM International, West Conshohocken, PA, 2011. [12] R. Newman, G. Gilbert, K. Lothridge, GC-MS Guide to Ignitable Liquids, CRC Press, Boca Raton, 1998.