A Comparison of Solvent Extract Cleanup Procedures in the Analysis of Organic Explosives

The use of an organic solvent to extract explosive residues from hand swabs and postblast debris inevitably leads to the coextraction of unwanted materials, usually in far greater quantities than any explosive residue. In this study, the extraction efficiency of a number of solvent cleanup procedures including solid‐phase extraction (SPE), adsorbent resins such as Chromosorb‐104, and traditional materials such as silica and Florisil was calculated using a quantitative liquid chromatography–ultraviolet (LC‐UV) detection procedure. The Oasis^® HLB cartridge outperformed other cleanup procedures, with analyte recoveries approaching 95%, while the Amberlite XAD‐7 procedure returned the lowest overall recoveries. The matrix rejection ability of each method was then determined using a simulated highly contaminated matrix, with the adsorbent resins showing a higher degree of matrix rejection, which is seen as a reduction in background noise in the UV chromatogram using 210 nm detection.     

Comparison of the Volatile Organic Compounds from Different Biological Specimens for Profiling Potential*

Previous work has demonstrated the ability to differentiate individuals based on the analysis of human scent hand odor chemicals. In this paper, a range of forensic biological specimens are shown to also have the ability to differentiate individuals based upon the volatile organic compounds (VOCs) present. Human VOC profiles from hand odor, oral fluid, breath, blood, and urine of 31 individuals were analyzed by solid‐phase microextraction–gas chromatography–mass spectrometry (SPME‐GC‐MS) and combined methods of chromatogram comparison, Spearman rank correlation comparison, and principal component analysis. Intra‐specimen comparisons demonstrated the distinguishability of individuals above 99%. Inter‐specimen VOC profiles from the same individual were found to be too different to be used for scent‐matching purposes, with Spearman rank coefficients below 0.15. A 6‐month VOC profile monitoring of two individuals demonstrated the consistency of VOC profiles over time across specimens.     

Profile of Hospital Admissions due to Self‐Inflicted Harm in Los Angeles County from 2001 to 2010

We aimed to describe the demographic profile of self‐inflicted harm (SIH) in Los Angeles County between 2001 and 2010 and to investigate trends over this 10‐year period. We used the California Hospital Discharge Data to investigate all cases of hospital admission due to SIH, including suicide attempts and if they had a concurrent psychiatric diagnosis based on ICD‐9 codes. African‐Americans (AA) had the highest 10‐year SIH admission rates. SIH admission rates remained steady throughout the 10‐year study period. Median age of SIH was significantly lower in Latinos. Episodic mood disorders were the most common psychiatric comorbidity. The use of solid/liquid poisoning was the most common SIH method among all racial/ethnic groups. We found major disparities in SIH admissions across racial/ethnic subgroups. The importance of programs to identify, prevent, and treat SIH in these groups is discussed.     

Relationship between the Change Rules of Volatile Organic Compounds in Rat Muscle and Postmortem IntervalCSCD

Objective: To explore the relationship between the change rules of volatile organic compounds (VOCs) in rat muscle and postmortem interval (PMI). Methods: A total of 120 healthy rats were divided randomly into 12 groups (10 for each group). After the rats were sacrificed by cervical dislocation, the bodies were kept at (25±1) ℃ Rat muscle samples were separately obtained at 12 PMI points, including 0, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 d. The VOCs in rat muscles were collected, detected and ana-lyzed by headspace solid-phase micro extraction (HS-SPME) coupled to gas chromatography-mass spec-trometer (GC-MS). Results: In total, 15 species of VOCs were identified, including 9 aromatic compounds, 3 sulfur compounds, 2 aliphatic acids and 1 heterocyclic compound. The species of VOCs increased with PMI: no species were detected within 1 day, 3 species were detected on day 2, 9 on day 3, 11 on day 4, 14 from day 5 to 7, and 15 from day 8 to 10. Total peak area of 15 species of VOCs was significantly correlated to PMI (adjusted R2=0.15-0.96): the regression function was y=-17.05 x2+164.36x-246.36 (adjusted R2=0.96) from day 2 to 5, and y=2.24x+101.13 (adjusted R2=0.97) from day 6 to 10. Conclusion: The change rules of VOCs in rat muscle are helpful for PMI estimation. © 2017 by the Editorial Department of Journal of Forensic Medicine.     

Ballpoint pen inks: the quantitative analysis of ink solvents on paper by solid-phase microextraction

We wish to describe further developments to a method previously reported on the detection of 2-phenoxyethanol in ink. The solid-phase microextraction (SPME) sampling technique, together with gas chromatography-mass spectrometry (GC-MS), has been used to quantify solvents in writing ink. In conventional approaches, the analysis of ink on documents requires some degree of destructive sampling. The methods commonly used remove ink samples from paper using a scalpel or a paper punch. To avoid document destruction, a sampling cell was constructed that allows solvents to be adsorbed directly onto the SPME fiber from the headspace above the document surface. Analytes (ink volatiles) are then desorbed from the SPME fiber on a gas chromatograph equipped with a mass selective detector (GC-MSD). With this method, it was possible to detect the presence of ink solvents on documents for a period lasting up to c. 2 years.     

现场勘查指挥中存在的问题及其对策探析

现场勘查工作对刑事案件的侦破起着十分重要的作用,随着法制化进程的不断推进,对现场勘查各环节的规范化要求日益提高。当前各级公安机关都十分重视犯罪现场勘查仪器、设备的投入,然而硬件的完善只能为做好犯罪现场勘查工作提供技术支持,因此加强对犯罪现场勘查的环节控制,提出有针对性的解决对策就显得十分重要。     

LC/MS分析血浆中丁丙诺啡

目的建立血浆中丁丙诺啡液相色谱/质谱（LC/MS）分析方法。方法在含有丁丙诺啡的血浆中,加入内标奋乃静,加pH10.8缓冲溶液,用401有机担体作吸附剂、三氯甲烷作洗脱剂固相萃取,N2挥干,用50μL流动相定容后进行LC/MS分析。色谱条件：Thermo Hypersil-HyPURITY C18（150×2.1mm,5μm）,柱温：40℃,流动相：10mmol/LNH4AC（pH3.4）∶甲醇∶乙腈=36∶52∶12,流速：0.22mL/min。结果方法的线性范围为0.05～5.0μg/L（r=0.9998）,定量限0.05μg/L,检出限0.01μg/L（S/N=3）;3个浓度的质量控制样品（0.1μg/L,0.5μg/L,2.0μg/L）平均回收率分别为86.40%,92.72%,92.57%,RSD分别为4.51%,3.34%,2.09%。结论该方法操作简便、灵敏度高,可用于涉毒案件血浆中丁丙诺啡的分析。     

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。     

中国城市生活垃圾处理绩效的影响因素：基于VAR模型的实证研究

文章通过主成分分析的方法构建和评价中国2006-2015年9年间各省(区、市)及整体的城市生活垃圾处理绩效综合水平,在此基础上利用VAR模型检验了多种因素对中国城市生活垃圾处理绩效影响做以实证研究。研究发现：直接影响中国城市生活垃圾处理绩效的主要因素是劳动力因素和运营模式因素。同时,运营模式因素是一种外生嵌套因素,没有外生驱动紧靠自身调整是无法实现的;而劳动力因素则除了自身调整外,还受到经费因素以及政府监管因素的间接驱动,即经费因素和政府监管因素通过劳动力因素路径间接影响绩效水平。据此,文章根据研究结论提出较具建设性的建议,以期对提升中国城市生活垃圾处理绩效水平以及指导公共事业的政府监管工作做以绵薄之力。     

“战后法”视野下联合国维和行动机制的制度化革新简

维持和平行动作为联合国维护国际和平与安全的一种重要方式,在避免冲突和恢复和平方面起到了重要作用.当前维和行动对传统维和原则的突破是国际环境变化和联合国实践相互作用的结果,维和行动由“冷却冲突”到“解决冲突”的嬗变也面临着许多困境,“战后法”为维和行动提供了新的理论基础和法律语境,能力建设是它对维和行动提出的新的要求,它有助于推动维和行动向更加系统化和规范化的方向发展.