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.     

Using Gas Chromatography with Ion Mobility Spectrometry to Resolve Explosive Compounds in the Presence of Interferents*

Abstract: Ion mobility spectrometry (IMS) is a valued field detection technology because of its speed and high sensitivity, but IMS cannot easily resolve analytes of interest within mixtures. Coupling gas chromatography (GC) to IMS adds a separation capability to resolve complex matrices. A GC‐IONSCAN^® operated in IMS and GC/IMS modes was evaluated with combinations of five explosives and four interferents. In 100 explosive/interferent combinations, IMS yielded 21 false positives while GC/IMS substantially reduced the occurrence of false positives to one. In addition, the results indicate that through redesign or modification of the preconcentrator there would be significant advantages to using GC/IMS, such as enhancement of the linear dynamic range (LDR) in some situations. By balancing sensitivity with LDR, GC/IMS could prove to be a very advantageous tool when addressing real world complex mixture situations.     

Validation of an LC–MS Method for the Detection and Quantification of BZP and TFMPP and their Hydroxylated Metabolites in Human Plasma and its Application to the Pharmacokinetic Study of TFMPP in Humans*

Abstract: An LC–MS method was developed for benzylpiperazine (BZP) and trifluoromethylphenylpiperazine (TFMPP), constituents of “party pills” or “legal herbal highs,” and their metabolites in human blood plasma. Compounds were resolved using a mixture of ammonium formate (pH 4.5, 0.01 M) and acetonitrile (flow rate of 1.0 mL/min) with a C18 column. Calibration curves were linear from 1 to 50 ng/mL (R² > 0.99); the lower limit of quantification (LLOQ) was 5 ng/mL; the accuracy was >90%; the intra‐ and interday relative standard deviations (R.S.D) were <5% and <10%, respectively. Human plasma concentrations of TFMPP were measured in blood samples taken from healthy adults (n = 6) over 24 h following a 60‐mg oral dose of TFMPP: these peaked at 24.10 ng/mL (±1.8 ng/mL) (C_max) after 90 min (T_max). Plasma concentrations of 1‐(3‐trifluoromethyl‐4‐hydroxyphenyl) piperazine peaked at 20.2 ng/mL (±4.6 ng/mL) after 90 min. TFMPP had two disposition phases (t_½ = 2.04 h (±0.19 h) and 5.95 h (±1.63 h). Apparent clearance (Cl/F) was 384 L/h (±45 L/h).     

液相色谱-质谱联用测定血中氟乙酸类鼠药

目的建立血中氟乙酸类鼠药液相色谱-电喷雾离子阱质谱分析方法。方法血样经甲醇沉淀蛋白后离心,上清液用氮气吹干,流动相定容过滤膜,滤液直接进行液相色谱-电喷雾离子阱质谱联用分析。结果血中氟乙酸根在0.050μg/mL-2.0μg/mL之间具有良好的线性关系,最低检出限为0.020μg/mL。结论本文建立的方法快速、灵敏、操作简便,适用于刑事案件中该类氟乙酸类鼠药的快速检验,具有一定的实用价值。     

Using Alkylate Components for Classifying Gasoline in Fire Debris Samples

The characteristic that discriminates gasoline from other ignitable liquids is that it contains high‐octane blending components. This study elaborates on the idea that the presence of gasoline in fire debris samples should be based on the detection of known high‐octane blending components. The potential of the high‐octane blending component alkylate as a characteristic feature for gasoline detection and identification in fire debris samples is explored. We have devised characteristic features for the detection of alkylate and verified the presence of alkylate in a large collection of gasoline samples from petrol stations in the Netherlands. Alkylate was detected in the vast majority of the samples. It is demonstrated that alkylate can be detected in fire debris samples that contain traces of gasoline by means of routine GC‐MS methods. Detection of alkylate, alongside other gasoline blend components, results in a more solid foundation for gasoline detection and identification in fire debris samples.     

Effect of Aging and Surface Interactions on the Diffusion of Endogenous Compounds in Latent Fingerprints Studied by Mass Spectrometry Imaging,

The ability to determine the age of fingerprints would be immeasurably beneficial in criminal investigations. We explore the possibility of determining the age of fingerprints by analyzing various compounds as they diffuse from the ridges to the valleys of fingerprints using matrix‐assisted laser desorption/ionization mass spectrometry imaging. The diffusion of two classes of endogenous fingerprint compounds, fatty acids and triacylglycerols (TGs), was studied in fresh and aged fingerprints on four surfaces. We expected higher molecular weight TGs would diffuse slower than fatty acids and allow us to determine the age of older fingerprints. However, we found interactions between endogenous compounds and the surface have a much stronger impact on diffusion than molecular weight. For example, diffusion of TGs is faster on hydrophilic plain glass or partially hydrophilic stainless steel surfaces, than on a hydrophobic Rain‐x treated surface. This result further complicates utilizing a diffusion model to age fingerprints.     

电热板消解电感耦合等离子体质谱法测定人发中33种无机元素的含量

目的建立头发中33种无机元素的电热板消解电感耦合等离子体质谱（inductivelycoupledplas—ma—IllasssDectrometry,ICP—MS）测定方法。方法以锂（6Li）、锗（^72Ge）、钇（^89Y）、铟（^115In）、铽（^159yb）作内标,硝酸和过氧化氢作为消解酸体系．采用电热板消解对头发进行前处理,ICP—MS法分析人发中33种无机元素的含量。结果电热板消解ICP—MS法的检出限为0．0001μg／g（Th）-10．9μg／g（Ca）,定量限为O．0005μg／g（Th）～25μg／g（Ca）,加标回收率为86％～113％,日内及日间精密度≤9.2％,与微波消解法检测结果相比,差异无统计学意义。结论电热板消解ICP—MS法高效、准确度高,适用于对头发中33种无机元素的分析。     

液相色谱-电喷雾离子阱质谱联用测定水中14种除草剂

目的建立水中14种除草剂液相色谱-电喷雾离子阱质谱联用分析方法。方法水样经固相萃取,洗脱液过膜后直接进行液相色谱-电喷雾离子阱质谱联用分析。结果水中14种除草剂定量分析线性关系良好,相关系数为0.995～0.998,检测限在0.005μg/mL～0.045μg/mL之间,在低、中、高3个不同浓度下,平均回收率在70.5%～110.2%之间,日内RSD均小于10.2%,日间RSD均小于14.4%。结论该方法具有快速、灵敏、高效等优点,能够满足相关司法鉴定工作的要求。     

3,4-亚甲二氧基甲卡西酮的鉴定

目的 建立基于傅里叶变换红外光谱(FTIR)、气相色谱-质谱(GC-MS)结合高分辨质谱技术联合鉴定未知样品的方法.方法 未知样品采用红外专用取样器直接检测;甲醇溶解后采用GC-MS和组合型高分辨质谱检测,以MDMA为内标物.结果 未知样品获得的红外光谱特征吸收峰为1679(C=O键),1603,1502,1453,1423,1259,1121,1090,1035,930,887,838,768,742和717cm-1,质谱特征碎片峰(m/z)为58.1,91.0,120.9,149.0和207.0,测得的精确质量数[M+H]+为208.0966.经信息分析未知样品鉴定为3,4-亚甲二氧基甲卡西酮,该物质属于新型化学合成卡西酮类精神活性物质,已经列入部分欧盟国家的管制药物目录.结论 本方法可用于3,4-亚甲二氧基甲卡西酮的鉴定.     

Analysis and Discrimination of Single‐Layer White Architectural Paint Samples,

Comparative analyses of 50 single‐layer white architectural paints were conducted to determine the discrimination power using standard techniques and to provide a basis for assessing significance when paints with limited features are not discriminated. Utilizing Fourier transform infrared spectroscopy (FTIR), 68 undifferentiated pairs resulted, yielding a discrimination of 94.45%. Adding stereomicroscopy, scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) and backscatter electron (BSE) imaging, and pyrolysis‐gas chromatography/mass spectrometry (Py‐GC/MS), the overall discrimination was 99.35%. The study included blind verification replicates, which resulted in the only pairs without indications of physical or chemical differences. The remaining groups of undifferentiated samples contained subtle differences by at least one technique, but were considered undifferentiated for the discrimination power evaluations. This study demonstrates a high degree of discrimination of single‐layer white architectural paints using methods of analysis often encountered in forensic science laboratories.