Analysis of artificial fireplace logs by high temperature gas chromatography

High temperature gas chromatography is used to analyze the wax of artificial fireplace logs (firelogs). Firelogs from several different manufacturers are studied and compared. This study shows that the wax within a single firelog is homogeneous and that the wax is also uniform throughout a multi-firelog package. Different brands are shown to have different wax compositions. Firelogs of the same brand, but purchased in different locations, also have different wax compositions. With this information it may be possible to associate an unknown firelog sample to a known sample, but a definitive statement of the origin cannot be made.     

Free Fatty Acids Composition in Adipocere of the Kwäday Dän Ts’ìnchí Ancient Remains Found in a Glacier*

Abstract: Adipocere is a postmortem decomposition product consisting of mostly a mixture of free fatty acids (FFAs) that are formed because of the hydrolysis of triglycerides in adipose tissues. This article describes a simple and robust method for the extraction, identification, and quantification of FFA commonly found in adipocere using gas chromatography–mass spectrometry (GC/MS). This method was applied to analyze tissues from Kwäday Dän Ts’ìnchí, ancient remains discovered in a retreating glacier in the Tatshenshini‐Alsek Park, British Columbia, Canada in August 1999. The lyophilized tissues were grinded and extracted with hexane. The trimethylsilyl fatty acid derivatives were analyzed by GC/MS, and the relative abundances of myristic acid, palmitic acid, oleic acid, and stearic acid were determined. Milligram per gram levels of saturated fatty acids were found in the tissues of the ancient remains, while the levels of unsaturated fatty acids, such as palmitoleic acid, were found to be negligible. The results provided further evidence of the existence of adipocere found during forensic examination of the Kwäday Dän Ts’ìnchí ancient remains.     

A preliminary investigation of the stages of adipocere formation

Adipocere is a postmortem decomposition product which forms from a body's adipose tissue. This study aimed to chemically demonstrate the process of conversion from adipose tissue to adipocere. Samples of adipocere were collected from pig cadavers that were allowed to decompose for varying intervals. Samples of soil were collected from beneath the cadavers and analyzed to determine the leaching effect of adipocere. Gas chromatography/mass spectrometry (GC/MS) was used to quantify the fatty acid composition of pig adipocere. Fourier transform infrared spectroscopy (FTIR) was used as a confirmatory test and to identify other components such as triglycerides and calcium salts of fatty acids. The study demonstrates the process of adipocere formation and the stages of formation through which the process passes using chemical techniques.     

Chemical composition of fingerprints for gender determination

This work investigates the chemical nature of fingerprints to ascertain whether differences in chemical composition or the existence of chemical markers can be used to determine personal traits, such as age, gender, and personal habits. This type of information could be useful for reducing the pool of potential suspects in criminal investigations when latent fingerprints are unsuitable for comparison by traditional methods. Fingertip residue that has been deposited onto a bead was extracted with a solvent such as chloroform. Samples were analyzed by gas chromatography/mass spectrometry (GC/MS). The chemical components identified include fatty acids, long chain fatty acid esters, cholesterol and squalene. The area ratios of ten selected components relative to squalene were calculated for a small preliminary experiment that showed a slight gender difference for three of these components. However, when the experiment was repeated with a larger, statistically designed experiment no significant differences between genders were detected for any of the component ratios. The multivariate Hotelling's T2 test that tested all ten-component ratios simultaneously also showed no gender differences at the 5% significance level.     

Alternative fuels in fire debris analysis: biodiesel basics

Alternative fuels are becoming more prominent on the market today and, soon, fire debris analysts will start seeing them in liquid samples or in fire debris samples. Biodiesel fuel is one of the most common alternative fuels and is now readily available in many parts of the United States and around the world. This article introduces biodiesel to fire debris analysts. Biodiesel fuel is manufactured from vegetable oils and/or animal oils/fats. It is composed of fatty acid methyl esters (FAMEs) and is sold pure or as a blend with diesel fuel. When present in fire debris samples, it is recommended to extract the debris using passive headspace concentration on activated charcoal, possibly followed by a solvent extraction. The gas chromatographic analysis of the extract is first carried out with the same program as for regular ignitable liquid residues, and second with a program adapted to the analysis of FAMEs.     

Extraction, derivatization, and analysis of vegetable oils from fire debris

Vegetable oils have the ability to spontaneously heat under certain conditions, which may lead to spontaneous ignition. While the oils are not often encountered in forensic casework, they may be suspected in some fire cases. As these oils are not effectively analyzed using traditional fire debris analysis methods, a protocol must be established for extracting vegetable oils from fire debris. In this study, a protocol was developed for the extraction, derivatization, and analysis of vegetable oils from fire debris. Three derivatization methods were compared to establish an optimal derivatization procedure to convert the fatty acids found in vegetable oils to the fatty acid methyl esters (FAMEs) used in analysis. Three different gas chromatograph columns and programs were examined to determine which was best suited for the separation and analysis of FAMEs. The procedure was tested and refined using a variety of neat and burned vegetable oils, in addition to extractions from oils burned on commonly encountered fire debris materials. The findings of this research will serve as a starting point for further understanding and research of vegetable oils in fire debris.     

Detection and Classification of Ignitable Liquid Residues in the Presence of Matrix Interferences by Using Direct Analysis in Real Time Mass Spectrometry,

Conventional Gas Chromatography‐Mass Spectrometry (GC‐MS) methods for the analysis of ignitable liquids (ILs) are usually time‐consuming, and the data produced are difficult to interpret. A fast IL screening method using direct analysis in real time mass spectrometry (DART‐MS) is proposed in this study. GC‐MS, QuickStrip DART‐MS, and thermal desorption DART‐MS methods were used to analyze neat ILs and thermal desorption DART‐MS without extraction was used to analyze ILs on five substrates (e.g., carpet, wood, cloth, sand, and paper). Compared to GC‐MS, DART‐MS methods generated different spectral profiles for neat ILs with more peaks in the higher mass range and also provided better detection of less volatile compounds. ILs on substrates were successfully classified (98 ± 1%) using partial least squares discriminant analysis (PLS‐DA) models based on thermal desorption DART‐MS data. This study shows that DART‐MS has great potential for the high‐throughput screening of ILs on substrates.     

Evaluation of a Headspace Solid‐Phase Microextraction Method for the Analysis of Ignitable Liquids in Fire Debris

The chemical analysis of fire debris represents a crucial part in fire investigations to determine the cause of a fire. A headspace solid‐phase microextraction (HS‐SPME) procedure for the detection of ignitable liquids in fire debris using a fiber coated with a mixture of three different sorbent materials (Divinylbenzene/Carboxen/Polydimethylsiloxane, DVB/CAR/PDMS) is described. Gasoline and diesel fuel were spiked upon a preburnt matrix (wood charcoal), extracted and concentrated with HS‐SPME and then analyzed with gas chromatography/mass spectrometry (GC/MS). The experimental conditions—extraction temperature, incubation and exposure time—were optimized. To assess the applicability of the method, fire debris samples were prepared in the smoke density chamber (SDC) and a controlled‐atmosphere cone calorimeter. The developed methods were successfully applied to burnt particleboard and carpet samples. The results demonstrate that the procedure that has been developed here is suitable for detecting these ignitable liquids in highly burnt debris.     

Postmortem decomposition of neutral lipids. Use of modern methods of analysis (HPLC, capillary GC, GC-MS and NMR) in adipocere formation

The chemical composition of subcutaneous fats was analyzed in a corpse that had died from drowning. The skin of the cadaver examined postmortem showed different stages of adipocere. Samples from these regions were chemically compared with the fatty tissue of a person who had died recently. HPLC, GC, GC-MS, NMR (1H- and 13C-NMR), TLC and titrimetrical methods were used to evaluate the degree of decomposition. The fatty acid pattern of the triglycerides (TG) and the free fatty acids (FFA) obtained by TLC separation was also investigated. Some discrepancy was observed between the autopsy findings and the results of the chemical analysis. It is suggested that the autopsy should be supplemented by chemical analysis in order to describe the state of adipocere correctly.     

GC‐MS and GC‐MS/MS in PCI Mode Determination of Mescaline in Peyote Tea and in Biological Matrices

Peyote, a cactus containing the hallucinogen mescaline, is used to induce altered states of consciousness in religious ceremonies or for recreational purpose. This study reports a case of an underage boy suspected of mescaline abuse. For this purpose, we analyzed a dark green liquid sample found in the bedroom of the boy whose urine and hair samples were collected shortly after the drink was found. A method by gas chromatography‐mass spectrometry tandem mass spectrometry (GC‐MS/MS) in positive chemical ionization mode was developed and validated in terms of linearity, specificity, accuracy, and sensitivity for mescaline determination at the low concentrations present in hair. GC‐MS analysis of the liquid identified mescaline, while urine was negative; GC‐MS/MS segmental hair analysis identified mescaline in the proximal segment (root to 2 cm), while the distal segments were negative. Although peyote was uncommonly encountered, its use was confirmed by segmental hair analysis that can provide long‐term information about drugs use.     

氟乙酸五氟苄基酯的气相色谱分析

目的 对氟乙酸根阴离子的衍生物-氟乙酸五氟苄基酯(PFB-MFA)进行了气相色谱分析，以满足氟乙酰胺类鼠药化验工作的需要。方法 使用GC／ECD、GC／MS Scan、GC／MS SIM对该化合物的标准溶液进行了分析，得到了各种分析方法的校正曲线及检测限。结果 三种方法测定PFB-MFA的线性范围分别为GC／ECD 0.01～0.1ng／μl、GC／MS SCAN 1～100ng／μl、GC／MS SIM 5×10~(-3)～1ng／μl。三种方法对氟乙酸根阴离子的检测限分别为：GC／ECD1.31×10~(-4)ng／μl、GC／MS SCAN 0.13ng／μl、GC／MS SIM 1.76×10~(-4)ng／μl。结论 氟乙酸根阴离子的衍生物氟乙酸五氟苄基酯在GC／ECD及GC／MS上具有一定的线性范围，有非常高的灵敏度，可用于法庭科学的定性定量分析。     

Identification of 2‐(ethylamino)‐1‐(4‐methylphenyl)‐1‐pentanone (4‐MEAP), a New “Legal High” Sold by an Internet Vendor as 4‐Methyl Pentedrone

Online vendors are offering a new legal high, 4‐methylpentedrone (4‐MPD). Information for potential users provided by internet vendors of 4‐MPD includes incorrect structures and nonexistent CAS numbers. A sample of 4‐MPD was obtained and analyzed using GC‐MS, NMR, and LC‐EIS. The fragmentation data from the GC‐MS and LC‐EIS produced an M‐1 ion that suggested the molecular mass was 219 amu, rather than 205 amu as calculated for 4‐methylpentedrone. The difference in molecular mass corresponded to the addition of a methyl group. Based on the mass and fragmentation pattern, two standards were synthesized, 2‐(ethylamino)‐1‐(4‐methylphenyl)‐1‐pentanone and 1‐(4‐methylphenyl)‐2‐(propylamino)‐1‐butanone. The synthesis involved bromination of the appropriate ketone followed by the reaction with ethylamine or propylamine. Based on the NMR data and unique fragmentation patterns produced by these molecules, the sample was identified as 2‐(ethylamino)‐1‐(4‐methylphenyl)‐1‐pentanone, not 4‐methylpentedrone.     

GC/MS衍生化测定精浆中游离支链氨基酸和果糖

目的 建立人精浆中支链氨基酸和果糖的气相质谱衍生化分析方法.方法 精液样本液化离心后,按精子活率的临床标准分为正常组和非正常组,经TMS微波衍生化,GC/MS分析两组支链氨基酸、果糖衍生物含量差异.结果 正常组与非正常组的缬氨酸,亮氨酸,异亮氨酸在相对含量上均有一定差异.正常组3种氨基酸相对含量高于非正常组.果糖分析观察到同样的特征,正常组相对含量高于非正常组.结论 精子活率低的精浆样本仍可检出支链氨基酸和果糖,其差异有助于无精子、少精子精斑的法医学鉴别.     

A review of the analysis of vegetable oil residues from fire debris samples: analytical scheme, interpretation of the results, and future needs

This paper reviews the literature on the analysis of vegetable (and animal) oil residues from fire debris samples. The examination sequence starts with the solvent extraction of the residues from the substrate. The extract is then prepared for instrumental analysis by derivatizing fatty acids (FAs) into fatty acid methyl esters. The analysis is then carried out by gas chromatography or gas chromatography-mass spectrometry. The interpretation of the results is a difficult operation seriously limited by a lack of research on the subject. The present data analysis scheme utilizes FA ratios to determine the presence of vegetable oils and their propensity to self-heat and possibly, to spontaneously ignite. Preliminary work has demonstrated that it is possible to detect chemical compounds specific to an oil that underwent spontaneous ignition. Guidelines to conduct future research in the analysis of vegetable oil residues from fire debris samples are also presented.     

Analytical Challenge in Postmortem Toxicology Applied to a Human Body Found into a Lake after Three Years Immersion

The body of a 30‐year‐old woman was found in Como lake at a depth of about 120 meters in her own car after 3 years of immersion. The aim of this study was to evaluate psychoactive drugs as well as alcohol biomarkers in biological matrices. The following analyses were initially performed: GC‐MS systematic toxicological analysis on biological fluids and tissues; GC‐MS analysis of drugs of abuse on pubic hair; direct ethanol metabolite determination in pubic hair by LC‐MS/MS. After 7 years, the samples, that had been stored at ?20°C, were re‐analyzed and submitted to an LC‐MS/MS targeted screening method, using multiple reaction monitoring mode. These analyses detected citalopram (150–3000 ng/mL), desmethylcitalopram (50–2300 ng/mL), clotiapine (20–65 ng/mL), and ethyl glucuronide (97 pg/mg). The methods showed an acceptable reproducibility, and the concentrations of citalopram and desmethylcitalopram calculated through the two analytical techniques did not significantly differ in biological fluids.     

Determination of the active principles of Catha Edulis: quali-quantitative analysis of cathinone, cathine, and phenylpropanolamine

In the last years, all the vegetable material supposed to belong to the Catha Edulis species, seized at the Malpensa and Orio al Serio airports, were analyzed in our laboratory on behalf of the Tribunals of Busto Arsizio and Bergamo, respectively. After a preliminary botanic examination, the quali-quantitative determination of the active principles cathinone, cathine and phenylpropanolamine (PPA) was carried out by means of GC/MS and GC/FID techniques, which meet the requirements of the forensic analyses. We developed a fast, effective and reliable derivatization procedure which allowed to simultaneously detect cathine and PPA, whose discrimination is mandatory since PPA is not a psychoactive agent. Cathine was distributed in the various parts of the plant (leaves and stems) and its quantity ranged from 0.03% to 0.17% of the weight of the vegetable material; PPA was not detected in the twigs and its quantity in the leaves ranged from 0.07% to 0.16%. The quantitative determination of cathinone was carried out directly on the methanol solution after maceration of the vegetable material, its quantity ranging from 0.02% to 0.10%. No significant difference in the content of the two active principles was found between the fresh and the dried material.     

Toxicological Analysis of Opiates from Alternative Matrices Collected from an Exhumed Body

In this case study, the body of a 45‐year‐old man was exhumed after 1 year at the request of the public prosecutor to assess whether the death was caused by drug consumption. Toxicological analyses were performed on several matrices, including liver, kidney, and the alternative matrices hair and teeth. The systematic toxicological analysis (STA), which consisted of basic and acid liquid/liquid extraction and gas chromatography–mass spectrometry (GC‐MS) analysis, showed the presence of opiates in each of the matrices analyzed. Subsequently, to confirm and quantify the presence of opioids, samples of each of the matrices were subjected to solid‐phase extraction and specific GC‐MS analysis. The case presented demonstrates the possibility of drug detection in an exhumed body that has been buried for 1 year, despite the problems of quantitative interpretation of the data, and that toxicological results could be useful along with other forensic evidence.     

Differentiation of side chain isomers of ring-substituted amphetamines using gas chromatography/infrared/mass spectrometry (GC/IR/MS).

Common analytical methods used for identifying samples obtained from clandestine laboratories were evaluated for their ability to differentiate between possible amphetamine isomers and homologs. A series of ring-substituted (4-methyl, 4-methoxy, and 3,4-methylenedioxy) amphetamine and N-methylphenethylamine isomers was analyzed using color tests, thin-layer chromatography, gas chromatography/mass spectrometry (GC/MS) and GC/infrared (GC/IR). The N-acetyl derivatives of the isomers were analyzed using GC/IR/MS. GC/IR/MS readily differentiated the 4-methylphenylalkylamine isomers. MS and IR spectra were also obtained for each pair of the 4-methoxyphenylalkylamine isomers and the 3,4-methylenedioxyphenylalkylamine isomers, but differentiation via GC/IR/MS was difficult. The N-acetyl derivatives of each pair of isomers could be readily differentiated using GC/IR/MS. Good library researchable spectra for N-acetylamphetamine could be obtained for IR identification with 10 ng (on-column) and MS identification with 2 ng. The spectrometrically independent IR and MS data obtained for the N-acetyl derivatives indicated that the combination of GC/IR/MS can add a significant level of confidence in the analysis of ring-substituted arylalkylamines.     

Effect of Gas Chromatography Temperature Program on the Association and Discrimination of Diesel Samples*†

Abstract: Five diesel samples were analyzed by gas chromatography–mass spectrometry (GC‐MS) using six GC temperature programs, aiming to investigate the effect of temperature program on association and discrimination of the samples. Temperature programs varied by ramp rate and incorporated one‐ or two‐step temperature ramps. Pearson product moment correlation coefficients and principal components analysis were used to evaluate differences in discrimination among the diesel samples afforded by each temperature program, based on the total ion chromatogram (TIC) and selected extracted ion profiles (EIPs). Association of diesel replicates and discrimination among samples based on the TIC and aromatic EIP were similar for all temperature programs based on scores plots. The alkane EIP was not useful in discriminating samples regardless of temperature program, because of similar alkane content of the diesel samples. The association and discrimination of diesel samples was largely unaffected by temperature programs that incorporated one‐ or two‐step temperature ramps.     

Headspace‐Gas Chromatographic‐Mass Spectrometric Analysis of South American Commercial Solvents and their Use in the Illicit Conversion of Cocaine Base to Cocaine Hydrochloride

This study presents data that establish the makeup of solvents utilized in illicit cocaine hydrochloride production, as determined via the identification of the occluded solvents in the crystal matrix of the final product. The occluded solvent ratios can differ dramatically from the ratios of the original processing solvents. Additionally, the presented data suggest the diversion of commercial solvents to illicit cocaine hydrochloride laboratories. Thirty‐five commercial solvents were obtained from five chemical manufacturing companies in South America. Each solvent was qualitatively and quantitatively analyzed using static headspace‐gas chromatography‐mass spectrometry (HS‐GC‐MS). After obtaining the chemical profile for each commercial solvent, solvents and/or solvent mixtures were prepared to be comparable in composition to several of the commercial products. Over 90 individual batches of cocaine hydrochloride were prepared from cocaine base using these solvents or solvent mixtures, which match those most commonly employed in clandestine laboratories. Additionally, a number of unique manufacturing by‐products produced from processing solvents were identified, and their significance is discussed.