Effect of electron beam irradiation on forensic evidence. 2. Analysis of writing inks on porous surfaces

The effect of electron beam irradiation on a series of different writing inks is described. As the anthrax-tainted letters were discovered in October 2001, the U.S. government began to experiment with the use of the electron beam irradiation process for destroying such biological agents. Plans initially considered a large-scale countrywide use of this technology. However, over time the scope of this plan as well as the radiation dosage were reduced, especially when some adverse consequences to mailed items subjected to this process were observed. Little data existed at the time to characterize what level of damage might be expected to occur with common items sent through the mail. This was especially important to museums and other institutions that routinely ship valuable and historic items through the mail. Although the Smithsonian Institution initiated some studies of the effect of electron beam irradiation on archived materials, little data existed on the effect that this process would have on forensic evidence. Approximately 97 different black, blue, red, green, and yellow writing inks were selected. Writing ink types included ballpoint, gel, plastic/felt tip, and rollerball. All noncontrol samples were subjected to standard mail irradiation conditions used by the U.S. Postal Service at the time this experiment was performed. A video spectral comparator and thin-layer chromatography (TLC) analysis were used to evaluate both the control and the irradiated samples. Some published studies reported changes in the presence/absence of dye bands in the chromatograms of irradiated writing inks. Some of these studies report the formation of additional dye bands on the chromatogram while others report missing dye bands. However, using standard testing guidelines and procedures, none of the 97 irradiated inks tested were found to show any significant optical or chemical differences from the control samples. In addition, random testing of some of the ink samples using a second solvent system did not reveal any changes. However, one control ink did show some minor changes in optical properties and dye characteristics over time (but not TLC) while the irradiated sample remained stable. Significant changes in the ultraviolet fluorescence characteristics of the irradiated paper samples themselves (not inks) were also observed.     

Quality assurance testing of an explosives trace analysis laboratory--further improvements

The Forensic Explosives Laboratory (FEL) operates within the Defence Science and Technology Laboratory (DSTL) which is part of the UK Government Ministry of Defence (MOD). The FEL provides support and advice to the Home Office and UK police forces on matters relating to the criminal misuse of explosives. During 1989 the FEL established a weekly quality assurance testing regime in its explosives trace analysis laboratory. The purpose of the regime is to prevent the accumulation of explosives traces within the laboratory at levels that could, if other precautions failed, result in the contamination of samples and controls. Designated areas within the laboratory are swabbed using cotton wool swabs moistened with ethanol water mixture, in equal amounts. The swabs are then extracted, cleaned up and analyzed using Gas Chromatographs with Thermal Energy Analyzer detectors. This paper follows on from a previous published paper describing the regime and summarizing subsequent results from approximately 6 years of tests. Lessons learned and improvements made over the period are also discussed. Monitoring samples taken from surfaces within the trace laboratories and trace vehicle examination bay have, with few exceptions, revealed only low levels of contamination, predominantly of RDX. Analysis of the control swabs, processed alongside the monitoring swabs, has demonstrated that in this environment the risk of forensic sample contamination, assuming all the relevant anti-contamination procedures have been followed, is so small that it is considered to be negligible. The monitoring regime has also been valuable in assessing the process of continuous improvement, allowing sources of contamination transfer into the trace areas to be identified and eliminated.     

血液中乙醇保存稳定性研究

目的确定血液中乙醇最佳保存条件,探讨影响血液中乙醇含量稳定性的主要因素。方法对血液保存的温度(-20、4、20℃)、防腐剂(NaF、无防腐剂、Na2O2)、储存容器中空气所占比例(0%、25%、50%)和血醇质量浓度(0.2、0.8、2.0mg/mL)四个因素采用正交试验L9(34)方法分组,样本采用顶空气相色谱法进行测定,测定结果采用方差分析进行讨论。结果在20℃保存且不加入防腐剂的两组样本中血醇浓度变化明显,其余变化不明显。结论血液样本在4℃、储存容器中空气比例为50%和加防腐剂(NaF)的条件下保存,稳定性最佳;四个影响因素中温度为影响血液中乙醇含量稳定性的主要因素。     

Quantitative Analysis of Gamma‐Hydroxybutyrate at Endogenous Concentrations in Hair using Liquid Chromatography Tandem Mass Spectrometry

Abstract: A method capable of quantifying endogenous concentrations of gamma‐hydroxybutyrate (GHB) in human head hair was developed and validated using liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS). Hair was digested under alkaline conditions, and GHB was isolated using liquid–liquid extraction. LC/MS/MS was performed using atmospheric pressure chemical ionization in the negative mode, multiple reaction monitoring, and deuterated internal standard (GHB‐D₆). Linearity was observed between 0.1 and 100 ng/mg GHB (R² = 1.000). The limits of detection and quantitation in human hair were 0.2 and 0.4 ng/mg, respectively. Accuracy at 2 ng/mg and 10 ng/mg was determined to be 97% and 94%, and intra‐assay CVs at these concentrations were 5.2% and 7.4% (n = 4). Beta‐hydroxybutyrate (BHB), alpha‐hydroxybutyrate, gamma‐butyrolactone, and 1,4‐butanediol did not produce an interference, and there was negligible ion suppression or enhancement from the matrix.     

Preliminary Studies into the Characterization of Chemical Markers of Decomposition for Geoforensics*

Abstract: In this paper, we report the results of our preliminary studies into chemical characterization of the fluids produced during decomposition in the absence of a soil matrix. Pig (Sus domestica) carcasses were used to model the human decomposition process in two separate locations, Western Australia (Perth) and Canada (Oshawa). Analysis involved simple dilution and filtration of the decomposition fluids followed by gas chromatography–mass spectrometry. Several previously unreported compounds were detected in the decomposition fluid samples during the trials, including benzeneacetic acid, benzenepropionic acid, 2‐piperidone, and isocaproic acid. Possible biosynthetic pathways for some of the compounds produced are proposed. Further research trials are required, particularly in the presence of soil matrices.     

固相萃取-气相色谱法提取全血中的外源性褪黑素

目的建立血样中褪黑素的固相萃取方法。方法采用OasisHLB固相萃取柱提取,GC/NPD定量检验,GC/MS定性检验。结果血样中褪黑素平均萃取回收率达80%以上,最低检出限0.02μg/mL,线性良好,相关系数R2=0.9978。结论该方法操作简便快速,提取回收率高,重现性好,提取物干净,可用于实际案件当中。     

顶空气相色谱内标法测定人血中乙醇含量的不确定度评定

目的建立顶空气相色谱内标法测定人血中乙醇含量的不确定度评定的方法。方法结合顸空法乙醇含量测定的全部过程,假设传播系数为1,则对产生不确定度的各分量因子进行分析计算与合成。结果不确定度因素的来源主要包含样品检测时产生的误差值、检测仪器的精密度、使用标准物质的标示值的不确定度和使用的量器、容量器皿等的不确定度。结论本评定方法得出检测的最大误差来自于两个平行样品检测时所产生的误差值。     

The analytical profile of some 4-methylthioamphetamine (4-MTA) homologues

The 4-methylthioamphetamine (4-MTA) is a sulphur-containing amphetamine-type stimulant (ATS), which appeared on the illicit market in Europe at the end of 90s. For the purpose of this study, several N-alkyl homologues of 4-MTA, including 4-methylthiomethamphetamine (4-MTMA), 4-methylthioethylamphetamine (4-MTEA), 4-methylthiodimethamphetamine (4-MTDMA), 4-methylthiopropylamphetamine (4-MTPA) and 4-methylthiobutylamphetamine (4-MTBA) were synthesized. The homologues were characterized by means of gas chromatography/mass spectrometry (GC–MS), infrared (IR) spectroscopy and the magnetic resonance spectroscopy (¹H and ¹³C NMR). The gas chromatography and mass spectrometry properties of their acetyl, trifluoroacyl (TFA), pentafluoropropionyl (PFP) and heptafluorobutyryl (HFB) derivatives were also investigated and discussed.     

5F-UR-144的热不稳定性研究

目的利用气相色谱-质谱法(GC-MS)、液相色谱-四级杆-飞行时间质谱(LC-Q-TOF/MS)和核磁共振光谱法(NMR)研究合成大麻素5F-UR-144遇热分解的具体变化情况。方法对照品用无水乙醇定容稀释后,经GC-MS和LC-Q-TOF/MS检测得到对应的色谱图和质谱图;对照品分别于常温和280℃密封加热后用无水乙醇定容稀释,经LC-Q-TOF/MS和NMR检测得到对应的质谱图、¹H和¹³C核磁共振波谱;对照品分别于常温逐步提升至300℃密封加热后用无水乙醇定容稀释,经LC-Q-TOF/MS检测得到对应的色谱图。结果5F-UR-144在高温下会开环产生新的物质;5F-UR-144从130℃开始分解,随着温度升高分解程度提升,240℃时分解率达到98%;随着温度继续升高,超过260℃,分解产物会碳化。结论基于5F-UR-144的热不稳定性,在检测时应考虑若通过烫食方式吸食5F-UR-144,其进入人体的成分会发生变化;气相色谱或气相色谱-质谱法不适合定量检测5F-UR-144。     

俄中石油天然气领域合作的几点思考

俄罗斯和中国分别为世界上最大的石油出口国和进口国之一 ,资源互补为双方能源合作提供了物质基础。但未来俄中两国在石油天然气领域的合作将在很大程度上取决于外部因素———世界能源市场的反常形势的影响。美国始终把控制能源放在国家利益的重要位置 ,在成功推倒萨达姆政权后 ,美国必将加强对中东的控制 ,从而控制世界能源的关键部分 ,获得未来世界石油市场中的主导权并主宰新世纪的石油价格。俄罗斯目前的主要战略问题是加强国家对油气田的控制 ,需要解决 3个根本任务 :1 在全球扩张的各种文明之间保持平稳 ;2 由国家控制自然资源的开采 ;3 国家加强对能源公司的控制。