Forensic Analysis of Stains on Fabric Using Direct Analysis in Real‐time Ionization with High‐Resolution Accurate Mass‐Mass Spectrometry

A rapid technique using direct analysis in real ‐ time (DART) ambient ionization coupled to a high ‐ resolution accurate mass‐mass spectrometer (HRAM‐MS) was employed to analyze stains on an individual's pants suspected to have been involved in a violent crime. The victim was consuming chocolate ice cream at the time of the attack, and investigators recovered the suspect's pants exhibiting splatter stains. Liquid chromatography with mass spectral detection (LC‐MS) and stereoscopic light microscopy (SLM) were also utilized in this analysis. It was determined that the stains on the pants contained theobromine and caffeine, known components of chocolate. A shard from the ceramic bowl that contained the victim's ice cream and a control chocolate ice cream sample were also found to contain caffeine and theobromine. The use of DART‐HRAM‐MS was useful in this case due to its rapid analysis capability and because of the limited amount of sample present as a stain.     

Acid alteration of several ignitable liquids of potential use in arsons

Ignitable liquids such as fuels, alcohols and thinners can be used in criminal activities, for instance arsons. Forensic experts require to know their chemical compositions, as well as to understand how different modification effects could impact them, in order to detect, classify and identify them properly in fire debris. The acid alteration/acidification of ignitable liquids is a modification effect that sharply alters the chemical composition, for example, of gasoline and diesel fuel, interfering in the forensic analysis and result interpretation. However, to date there is little information about the consequences of this effect over other accelerants of interests. In this research paper, the alteration by sulfuric acid of several commercial thinners and other accelerants of potential use in arsons is studied in-depth. For that purpose, spectral (by ATR-FTIR) and chromatographic (by GC–MS) data were obtained from neat and acidified samples. Then, the spectral and chromatographic modifications of each studied ignitable liquid were discussed, proposing several chemical mechanisms that explain the new by-products produced and the gradual disappearance of the initial compounds. Hydrolysis, Fischer esterification and alkylation reactions are involved in the modification of esters, alcohols, ketones and aromatic compounds of the studied ignitable liquids. This information could be crucial for correctly identifying these accelerants. Additionally, an exploratory analysis revealed that some of the most altered ignitable liquid samples might be very similar with each other, which could have impact on casework.     

Preparation and characterization of micro-bore wall-coated open-tubular capillaries with low phase ratios for fast-gas chromatography–mass spectrometry: Application to ignitable liquids and fire debris

Fast Gas Chromatography (GC) allows for analysis times that are a fraction of those seen in traditional capillary GC. Key modifications in fast GC include using narrow, highly efficient columns that can resolve mixtures using a shorter column length. Hence, a typical fast GC column has an inner diameter of 100–180 μm. However, to maintain phase ratios that are consistent with typical GC columns, the film thickness of fast GC stationary phases are also low (e.g., 0.1–0.18 μm). Unfortunately, decreased film thickness leads to columns with very low sample capacity and asymmetric peaks for analytes that are not sufficiently dilute. This paper describes micro-bore (50 μm i.d.) capillary columns with thick films (1.25 μm), and low phase ratios (10). These columns have greater sample capacity yet also achieve minimum plate heights as low as 110 μm. Hence, separation efficiency is much higher than would be obtained using standard GC columns. The capillary columns were prepared in-house using a simple static-coating procedure and their plate counts were determined under isothermal conditions. The columns were then evaluated using temperature programming for fast GC–MS analysis of ignitable liquids and their residues on fire debris exemplars. Temperature ramps of up to 75 °C min^?1 could be used and separations of ignitable liquids such as gasoline, E85 fuel, and lighter fluid (a medium petroleum distillate) were complete within 3 min. Lastly, simulated fire debris consisting of ignitable liquids burned on carpeting were extracted using passive headspace absorption-elution and the residues successfully classified.     

高效液相色谱法快速分离测定血浆中的乌头碱

目的建立血液中乌头碱的高效液相色谱快速分析方法。方法以空白人血浆添加乌头碱标准品对血液样品的前处理方法、仪器测试条件、线性范围、精密度、回收率进行全面考查,建立乌头碱定量分析方法。对血液中所含乌头碱的浓度进行测定。结果该方法在血液中的线性范围是0.1~5.0μg/m l;最低检测浓度为0.1μg/m l;日内、日间精密度分别小于3.7%和4.5%;回收率在(97.0±4.1)%以上。结论所建方法实用、便捷,可对血液中乌头碱的含量进行快速测定。     

有毒生物碱阿托品的检验现状

阿托品是一种抗胆碱药,可用于有机磷农药中毒的抢救,但因其本身具有毒性和致幻性,常被滥用并导致中毒甚至死亡,又可被添加至可卡因等毒品中。目前,阿托品的主要检测方法有气相色谱、液相色谱和毛细管电泳,本文综述了这几种方法检测阿托品的现状。     

快速溶剂萃取-凝胶色谱净化-LC／MS／MS相结合测定血中的杀参毒素类农药

目的建立血中杀参毒素类农药残留的快速分析方法。方法取一定量的Al2O3放入萃取池中做吸附剂,通过快速溶剂萃取仪萃取血液中杀参毒素类农药,同时达到在线净化的效果,后运用凝胶色谱净化联用仪进一步净化浓缩到2ml,提取液经LC／MS／MS进行检验。结果杀虫双在1．2×10g／ml～1．2×10^-6g／ml范围内线性关系良好,检出限为0．04ppb,杀虫眯为1．2×10^-6g／ml～7．2×10g／ml,检出限为0．34ppm。2种杀参毒素农药的平均回收率为89％、90％,相对标准偏差为1．9％、3％。结论整个方法简便、快速、准确、重现性好、灵敏度高,杂质干扰少。     

姬松茸液体发酵条件的研究

该文对姬松茸液体发酵条件进行了研究。考察了发酵时间对姬松茸液体发酵的影响,确定最佳发酵周期为9天.对发酵培养基中葡萄糖、豆粕及麸皮这三个组分选择了三水平进行正交试验、方差分析。结果表明发酵培养基中葡萄糖组分对姬松茸生物量的影响极显著。最优培养基组合为葡萄糖3%,麸皮1.5%,豆粕1.5%。按最优培养基组合进行发酵试验,姬松茸生物量可达到最高值8.576 g/L。     

The identification of the emulsifier component of emulsion explosives by liquid chromatography-mass spectrometry

ABSTRACT: The widespread availability of emulsion explosives for commercial blasting has inevitably lead to their diversion for criminal misuse. Present techniques for the characterization of emulsion explosives and their residues is generally based on the detection and identification of the oxidizer and the hydrocarbon components. Use of these components is problematic for residue identification because ammonium nitrate, waxes, and oils are relatively common in the urban environment and even their co-detection does not exclude them being sourced from materials other than explosives. The detection of the emulsifier component offers increased evidential value as certain emulsifiers used in explosive formulations are manufactured for that specific use, or have limited environmental distribution. In the current study liquid chromatography-mass spectrometry (LC-MS) was utilized for the characterization of two emulsifiers in common use; ethanolamine adducts of polyisobutylene succinic anhydride and sorbitol mono-oleate (SMO). The LC-MS technique enabled the detection of both emulsifiers in preblast samples; however, only SMO was detected in postblast residues. The analysis of the hydrocarbon component by gas chromatography-mass spectrometry was achieved in the same procedure.     

怀牛膝蜕皮甾酮的含量测定

目的：测定怀牛膝中蜕皮甾酮的含量测定。方法：采用高效液相色谱法测定怀牛膝中蜕皮甾酮的含量。结果：蜕皮甾酮在0．2～1．8μg范围内线性关系良好。结论：本方法操作快速、简便、准确，可作为蜕皮甾酮的定量分析方法。     

RP-HPLC法测定晕复静片中士的宁的含量

目的 :建立RP HPLC法测定晕复静片中士的宁含量的分析方法。方法 :采用反相高效液相色谱法 ,使用Kromasil C18色谱柱 (5 μm ,15 0mm× 4 .6mm) ,以水 甲醇 乙酸 三乙胺 (2 0 0∶10 0∶2 .0∶0 .3)为流动相 ,流速 1.0ml/min ,检测波长为 2 5 4nm。结果 :本方法线性关系良好 ,线性范围0 .172 8～ 0 .86 40 μg (r =0 .9994 ) ,士的宁的平均加样回收率为 99.3% ,RSD =0 .5 %。结论 :本方法操作简便 ,分离效果好 ,结果准确 ,可用于晕复静片的质量控制。