用GC-MS/MS法检验生物检材中的氟乙酰胺

<正>氟乙酰胺、氟乙酸钠属有机氟类毒鼠药，由于其水溶性强、易被吸收、毒性大。进食毒死的家禽、牲畜可引起二次中毒。近年来用此类药物进行投毒、误服和自杀的案件经常发生，已成为刑事中毒案件最常见的毒物之一。对生物检材中氟乙酸的检验，国内外均有报道，主要有硫靛法、液相色谱法和衍生化后的GC-NPD、GC-ECD法。其中硫靛法定性不可靠，液相色谱     

硫靛反应检验氟乙酰胺的方法研究

通过实验研究了硫靛反应检验氟乙酰胺的干扰、灵敏度、最佳实验条件和方法。结果表明，当该反应条件适当时，硫靛反应干扰少，灵敏度高，仍不失为检验鼠药氟乙酰胺较为理想的化学反应。     

硫靛反应的改进方法

常规氟乙酰胺的硫靛反应费时、灵敏度不高且易出现假阴性.采用保险丝做催化氧化剂,在碱性条件下直接加热氟乙酰胺(或氟乙酸)与硫代水杨酸生成洋红色硫靛.蒸发皿中加入3cm保险丝,酒精灯加热至熔化,冷却后加入氟乙酰胺,硫代水杨酸溶液0.5ml,1N氢氧化钠1～2滴,石棉网上酒精灯加热至近干时,上部盖一蒸     

硫靛反应检验氟乙酰腔的方法研究

通过实验研究了硫靛反应检验氟乙酰胶的干扰、灵敏度、最佳实验条件和方法，结果表明，当该反应条件适当时，硫靛反应干扰少，灵敏度高，仍不失为检验鼠药氟乙酰胺较为理想的化学反应。     

硫靛反应检验氟乙酰胺的方法改进

目的改进和完善硫靛反应检验氟乙酰胺的方法。方法用紫外可见分光光度计和气质联用仪检测硫靛反应产物。结果紫外可见分光光度计和气质联用仪检测硫靛反应产物特异性强、灵敏度高。结论该方法解决了硫靛法检验氟乙酰胺准确性不强的问题。     

GC／MS分析氟乙酰胺中的杂质推断鼠药来源初探

氟乙酰胺（Fluoroactamide）由于毒性大，具有二次中毒的特点，对人畜毒害较大，国家已明令禁止生产，但是因其生产合成容易，灭鼠效果明显，目前仍有一些不法商贩制造和贩卖。投毒、误服或自服氟乙酰胺案件也较常见。本文用GC／MS法对氟乙酰胺中的杂质进行检验，为推断氟乙酰胺涉毒案件中的鼠药来源进行初步探索。     

氟乙酰胺、氟乙酸中毒代谢产物“氟柠檬酸”的GC／MS分析研究

目的　分析研究氟乙酰胺、氟乙酸中毒代谢产物“氟柠檬酸”。　方法　采用家兔分时段喂食氟乙酰胺、氟乙酸和作者合成的“氟柠檬酸” ,然后从家兔组织中提取氟柠檬酸并进行GC/MS分析。　结果　中毒致死的家兔未检出氟柠檬酸成分 ,仅喂食氟柠檬酸致死的家兔体内可检出氟柠檬酸成分。　结论　氟乙酰胺、氟乙酸在动物体内不能代谢成氟柠檬酸。     

GC/ECD检验生物检材中的氟乙酸钠

建立对生物检材中氟乙酸钠的GC/ECD检验方法。用PFBBr作衍生化试剂,对氟乙酸钠或氟乙酰胺中毒后脏器中的氯乙酸（氯乙酸钠）进行衍生化,GC/ECD和GC／MS的分析。在1ml血中添加lμg1080,其回收率为76．2％,RSD为3．07（n＝7）;在1g肝中添加2μg的1080其回收率为84．4％,RSD为1．87（n=5）。研究的方法经动物试验和大量中毒案件的验证,效果较好。该方法已在中毒案件的检验中广泛应用。     

GC/MS检验氟乙酸类鼠药的硫代水杨酸环化衍生物

氟乙酸类鼠药包括氟乙酰胺、氟乙酸和氟乙酸钠等。氟乙酰胺和氟乙酸钠都是效力很强的杀鼠剂。氟乙酰胺纯品为白色、无臭、无味的针状结晶,熔点107℃～108℃,受热可升华,170℃分解;溶于水、甲醇、乙醇等溶剂,在二氯甲烷、氯仿、乙醚中的溶解度较小,难溶于石油醚;干燥条件下较稳定,水溶液中能水解成氟乙酸;酸和碱可使水解加速,分别生成氟乙酸和氟乙酸盐。氟乙酸是比醋酸强的有机酸,熔点33℃,沸点165℃,能溶于水和醇。氟乙酸钠又名1080、氟醋酸钠,其纯品为白色结晶,加热至200℃时分解;有吸湿性,极易溶于水,微溶于丙酮、乙醇和油类犤1犦。氟乙酸…     

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。     

SELF-CONTROL AND INTIMATE VIOLENCE: AN EXAMINATION OF THE SCOPE AND SPECIFICATION OF THE GENERAL THEORY OF CRIME*

Ambiguities in Gottfredson and Hirschi's general theory of crime have generated doubts about the explanatory scope of the theory and inconsistencies in the specification of models attempting to test it. In particular, the theory has been criticized for its inability to explain intimate violence; however, an empirical test of this criticism cannot be conducted appropriately unless the theoretical model has been adequately specified. This study tests four models of self-control theory for their ability to explain one form of intimate violence: courtship aggression. Logistic regression analysis was used to assess the ability of measures of low self-control, opportunity, and perceptions of reward to predict the probability of courtship violence in a sample of 985 students currently involved in a dating relationship. The results indicate that while the main effects of low self-control, opportunity, and perception of immediate gratification are significant predictors of the probability of using violence in a dating relationship, it is less clear whether the functional form of the theoretical model accommodates the interaction between low self-control and either opportunity or perceived rewards.     

刺激性毒剂希埃斯(CS)的检验

用化学显色法、红外光谱法(IR),以及色-质联用技术(GC/MS)分析具有强烈刺激性气味的毒剂希埃斯(CS),在缺少已知对照样的情况下,用以上方法,可做出准确的鉴定.     

Students’ foundational understanding of chemical reaction in the forensic science bachelor’s degree program at the National Autonomous University of Mexico

ObjectiveTo compare the understanding of the concept of chemical reaction—as operationalized by Bloom’s taxonomy of cognitive levels—of students in forensic science bachelor’s degree with that achieved by students majoring in chemistry, as a prerequisite for future professional collaboration and communication.Materials and methodsUsing previously validated and published tests developed to assess students’ knowledge, comprehension, and application of the concept of chemical reaction, we explored how conceptual understanding developed in students enrolled in (a) a forensic science degree program in a Mexican public university and in (b) chemistry undergraduate programs offered by the same university, and whether both groups achieved comparable attainment levels.Findings and implicationsDespite receiving considerably less chemical instruction, forensic science students achieved comparable levels of conceptual understanding of chemical reaction to those exhibited by chemistry students. This finding is encouraging because it might mean that future forensic scientists could graduate with a solid foundation of chemical knowledge. More research, particularly on the learning of other key concepts, will be needed to verify these initial findings.     

嗅觉模拟技术在火灾探测中的应用

如何极早期并且准确探测到火灾历来是火灾探测研究的重点内容之一。近年来,基于气敏传感器阵列与模式识别方法的嗅觉模拟技术成为国内外研究的热点,并且成功应用于环境监测、医疗诊断、医药及食品工业、化工、军事等领域。目前已经有人尝试将其应用于火灾探测方面。将嗅觉模拟技术应用于火灾探测的实质就是利用嗅觉模拟系统中仿生的气敏元件感应火灾前(中)物质受热分解(燃烧)释放出的气味,这个感应时间早于火灾发生时间、甚至是阴燃发生的阶段,即早于传统火灾探测器的响应时间。所以将其应用于火灾探测领域可以解决以往火灾探测器响应时间晚、响应不准确的关键技术问题。嗅觉模拟技术在火灾探测方面表现出良好的发展潜力。     

Automated SEM/EDS Analysis of Airbag Residue. II: Airbag Residue as a Source of Percussion Primer Residue Particles

Abstract:  Automated scanning electron microscopy with energy dispersive spectroscopy has been used to analyze airbag residue particles. Analysis of airbag residue from some passenger side airbags revealed some residue particles which are consistent with gunshot residue (GSR) samples. The source of these particles was determined to be percussion primers used to initiate the chemical reaction for deployment. This article identifies some vehicles which contain this type of airbag and demonstrates the types of particles which could be misidentified as being GSR. The low numbers of GSR particles in among the large particle populations of zirconium and/or copper–cobalt particles, which are clearly airbag residue, allow the trained analysts to distinguish the correct source of this residue. Particles containing high aluminum levels, elevated levels of allowable elements in GSR particles, or the presence of elements that are rare in GSR particles stand out as indications that the particles are not GSR in origin. This study serves as a guide to analysts who perform particle analysis in forensic investigations.     

A THEORY OF HOMICIDAL BEHAVIOR AMONG WOMEN*

This theory explains the homicidal behavior of women in a variety of settings. Structural, social, and cultural conditions of modern societies generate strain for all women, which produces negative affect. Women tend to internalize negative affect as guilt and hurt rather than externalize it as anger directed at a target. This results in a situation analogous to overcontrolled personality, and results in low overall rates of deviance punctuated by occasional instances of extreme violence. The conditions found in long-term abusive relationships and pre- or post-partum environments are more likely to produce this result, but the theory is not limited to explaining female homicide in these settings.     

REASSESSING THE BREADTH OF THE PROTECTIVE BENEFIT OF IMMIGRANT NEIGHBORHOODS: A MULTILEVEL ANALYSIS OF VIOLENCE RISK BY RACE,ETHNICITY, AND LABOR MARKET STRATIFICATION*

Researchers in the United States have increasingly recognized that immigration reduces crime, but it remains unresolved whether this applies to people of different racial–ethnic and economic backgrounds. By using the 2008–2012 area‐identified National Crime Victimization Survey (NCVS), we evaluate the effect of neighborhood immigrant concentration on individual violence risk across race/ethnicity and labor market stratification factors in areas with different histories of immigration. The results of our analysis reveal three key patterns. First, we find a consistent protective role of immigrant concentration that is not weakened by low education, low income, unemployment, or labor market competition. Therefore, even economically disadvantaged people enjoy the crime‐reduction benefit of immigration. Second, we find support for threshold models that predict a nonlinear, stronger protective role of immigrant concentration on violence at higher levels of immigrant concentration. The protective function of immigration also is higher in areas of longer histories of immigration. Third, compared with Blacks and Whites, Latinos receive a greater violence‐reduction benefit of immigrant concentration possibly because they live in closer proximity with immigrants and share common sociocultural features. Nevertheless, immigrant concentration yields a diminishing return in reducing Latino victimization as immigrants approach a near‐majority of neighborhood residents. The implications of these results are discussed.     

Reagents for the chemical development of latent fingerprints: scope and limitations of benzo[f]ninhydrin in comparison to ninhydrin

Benzo[f]ninhydrin was compared to ninhydrin for fingerprint development on paper. Overall, the performance of ninhydrin on exhibits was slightly better than that of benzo[f]ninhydrin. The significant advantages of the benzo[f]ninhydrin over ninhydrin were the much stronger fluorescence it gave after treatment with zinc salts and a slightly quicker reaction under ambient conditions. This fluorescence is, however, similar to that obtained with other reagents, such as DFO or ninhydrin analogs. These advantages apparently are not sufficient to justify regular usage of benzo[f]ninhydrin, especially when one considers its low solubility and high cost.     

Unlocking the potential of forensic traces: Analytical approaches to generate investigative leads

Forensic investigation involves gathering the information necessary to understand the criminal events as well as linking objects or individuals to an item, location or other individual(s) for investigative purposes. For years techniques such as presumptive chemical tests, DNA profiling or fingermark analysis have been of great value to this process. However, these techniques have their limitations, whether it is a lack of confidence in the results obtained due to cross-reactivity, subjectivity and low sensitivity; or because they are dependent on holding reference samples in a pre-existing database. There is currently a need to devise new ways to gather as much information as possible from a single trace, particularly from biological traces commonly encountered in forensic casework. This review outlines the most recent advancements in the forensic analysis of biological fluids, fingermarks and hair. Special emphasis is placed on analytical methods that can expand the information obtained from the trace beyond what is achieved in the usual practices. Special attention is paid to those methods that accurately determine the nature of the sample, as well as how long it has been at the crime scene, along with individualising information regarding the donor source of the trace.     

Amino acid alanine reactivity with the fingerprint reagent ninhydrin. A detailed ab initio computational study

Ninhydrin is one of the most widely used reagents for chemical development of fingerprints on porous surfaces. The detection is based on the reaction of ninhydrin with a monoacidic component of the fingerprint to form an intensively colored compound named Ruhemann's Purple. A computational study of the mechanisms and reaction energetics of the formation of Ruhemann's Purple from ninhydrin and alanine is presented. Such a study is significant from a forensic science point of view because of the strong interest in the forensic chemistry and law enforcement communities in developing alternatives to the current generation of ninhydrin like chemicals for the detection and development of latent fingerprints. Information about the mechanism of reaction between ninhydrin and amino acids can ultimately help to design compounds with stronger chromo-fluorogenic properties in aid of detecting fingerprints at crime scenes. The three most accepted mechanisms of formation have been considered using ab initio quantum mechanical calculations. At relatively high temperature ( approximately 100 degrees C) all three mechanisms are energetically feasible. However since it is recommended that forensic analyses be performed at room temperature, a revised mechanism is proposed for the formation of Ruhemann's Purple under this condition.