基于功能材料的固相微萃取技术及其在法庭科学领域中的应用

样品的提取是法庭科学分析中至关重要的一步,尤其是在处理各种复杂基质(如土壤、生物样品、火灾残留物等)中痕量和超痕量的目标分析物时。传统样品前处理技术如索氏提取、液液萃取等,步骤繁琐,耗时耗力,过程中易造成样品的损失和二次污染,且萃取所需的大量溶剂还会对环境及研究人员的健康构成威胁。为此,无需或只需少量溶剂的固相微萃取技术(SPME)应运而生,其小巧便携,操作简单、快速,易于实现自动化等特点使之成为广泛应用的样品前处理技术。早期的研究大多采用商品化SPME装置,然而它的种类有限、价格昂贵、纤维易断、选择性不足,因此,近年来使用金属有机骨架化合物、共价有机骨架化合物、碳基材料、分子印迹聚合物、离子液体、导电聚合物等各种功能材料制备SPME涂层的技术越来越受到关注,在环境监测、食品分析及药物检测等方面应用广泛。然而这些SPME涂层材料在法庭科学领域的应用相对较少,考虑到SPME技术应用于犯罪现场样品原位高效提取的巨大潜力,该文对功能涂层材料进行了简要介绍,系统总结了基于功能材料的SPME技术在炸药、助燃剂、毒品、毒物、油漆、人体气味等分析中的应用,并指出了基于功能材料的SPME技术在法庭科学...     

人体气味的存留时间

应用质量变化法及固相微萃取-气相色谱-质谱法对人体气味在一定空间内的存留时间进行了研究.试验结果表明:在平均温度为25℃,平均相对湿度为64%的房间内,人体气味可存留至少60d,而且至少在20d内人体气味具有较好的质的稳定性.此外,借固相微萃取技术与气相色谱-质谱联用法相结合,检测到人体气味中常见的25种组分.     

人体腋窝气味的固相微萃取GC-MS分析

采用固相微萃取顶空进样技术和气相色谱-质谱法对人体的腋窝气味进行了分析，探讨了腋窝气味样品的采样方法和分析条件；利用70μm乙烯二醇-二乙烯基苯共聚物(CW-DVB)萃取头对43个人体腋窝气味样品进行了分析，一般获得98～105个色谱峰，检出了36个化合物；发现人体腋窝气味是由脂肪酸、酯、醇、胺、酮等物质组成，多次分析同一个体气味样品的色谱图有较好的相似性；从总的取样及分析结果看，利用固相微萃取顶空进样气相色谱-质谱技术在人体气味的分析研究中有着较好的应用前景。     

微波萃取气相色谱法分析全血中的甲基苯丙胺

苯丙胺(又称安非他明,amphetamine)类毒品是一类非法人工合成的有机胺类兴奋剂,它主要作用于中枢神经和交感神经,属于中枢神经兴奋类毒品,其中甲基苯丙胺(俗称冰毒)最常被滥用.由于苯丙胺类毒品的滥用现象日趋严重,对社会危害极大.因此,对该类毒品的分析研究不仅意义重大,而且十分迫切.目前,国内外报道的生物样品中苯丙胺类毒品的前处理方法主要有液液萃取、固相萃取及固相微萃取等方法.近年来,微波辅助萃取(microwave-assisted extraction,MAE)因其萃取时间短、回收率高、试剂用量少、污染小和可自动控制制样条件而得到了分析工作者的认同,并已应用于土壤、沉积物中有机芳烃[1]以及生物样品中农药残留[2]的萃取研究,而在法庭科学上的应用极少报道.本文对全血中的甲基苯丙胺进行了初步的微波萃取技术研究,建立了微波萃取气相色谱法分析生物样品中甲基苯丙胺的方法.     

萃取-表面增强拉曼光谱联用技术及其在有害物质检测领域的应用

表面增强拉曼光谱(SERS)技术以其高灵敏度和分子特征指纹光谱在众多领域获得广泛应用,然而对于实际复杂样品中的目标分析物,样品基质会极大地干扰目标分析物SERS信号的准确获取,从而限制SERS在实际样品分析中的应用.萃取-表面增强拉曼光谱(Ex-SERS)联用技术为解决这一现实难题提供了可能性,国内外课题组结合萃取和SERS的各自优势,构建了基于固相萃取、固相微萃取、磁分散固相微萃取、薄层微萃取、液液分散微萃取、擦拭萃取等多种Ex-SERS联用技术,并以此发展了面向多种有害物质的Ex-SERS联用方法,可实现复杂基质中目标分析物的快速原位分离和SERS检测,进一步拓展SERS在实际样品分析中的应用.     

药毒物分析中磁性固相萃取技术的应用进展

磁性固相萃取是一种新型的样品前处理技术,具有萃取时间短、吸附能力强、有机溶剂使用量少、操作简单快捷等优点,已经广泛应用于样品的分离提纯.在简要介绍磁性固相萃取技术发展、材料制备的基础上,着重对国内外磁性固相萃取技术在药毒物分析方面的发展现状以及应用进展进行了综述,以期为法庭科学领域相关物证鉴定提供参考,为严厉打击相关违法犯罪活动提供科学理论与实践依据.     

活体固相微萃取技术在动植物体内污染物分析中的应用

固相微萃取作为一种简便、快速、绿色的采样和样品前处理技术,近年来引起了广泛关注。在活体分析领域,基于相关萃取动力学理论的发展和新型活体采样探针的研制,固相微萃取技术逐步用于不同动植物体系中多种污染物的分析。本文概述了固相微萃取活体定量校正方法的开发、活体采样动力学过程的研究、新型活体采样探针的制备,以及活体固相微萃取方法在动植物组织中污染物快速检测及污染物富集和消除过程跟踪研究中的应用。此外,本文也对活体固相微萃取技术今后的发展方向和应用前景进行了展望。     

基于量子点的检测技术在法庭科学物证鉴定中的应用研究进展

由于具有独特的纳米尺寸效应和高灵敏度的光电效应,碳量子点以及半导体量子点技术已经被广泛应用于材料科学、生物和医药等领域。本文在简述量子点结构、合成方法等基础上,着重介绍了基于量子点的检测技术在法庭科学领域毒物、毒品和微量物证鉴定中的应用,旨在分析基于量子点的检测技术研究与应用现状,展望其在法庭科学领域中的应用前景。     

微萃取技术在环境分析中的应用

微萃取技术是近年来出现的绿色样品前处理技术。它具有操作简便、环境友好等优点,并且在环境、医药及食品等领域得到广泛的应用。本文仅就固相微萃取和液相微萃取在环境分析中的应用作一简要综述。     

固相微萃取GC-MS快速分析火场残留物中汽油成分

火场残留物如碳灰、烧残物等通常经过样品预处理后进行分析鉴定。传统的样品预处理方法往往操作繁琐、费时、重复性差,而且需用大量有机溶剂,不利于分析人员的身体健康,对环境也会造成一定污染。固相微萃取(solid-phasemicroextraction,SPME)是在固相萃取技术的基础上发展起来的一项新的样品预处理技术,于1989年由加拿大Waterloo大学的J.Pawliszyn教授等首次提出,1993年美国的Supelco公司推出了商业化的固相微萃取设备。该技术具有快速、高效、简便、无需溶剂、易于自动化操作等优点,近年来受到了国外学者的普遍关注,已经被用于环境分析和药品检测等许多领域,     

The use of solid-phase microextraction--gas chromatography in forensic analysis

A thorough review of the application of solid-phase microextraction (SPME) combined with gas chromatography for the analysis of forensic specimens is presented, including experimental results for several recent applications. The SPME applications covered in this comprehensive review include ignitable liquid residues (also referred to as accelerants), explosive traces, drugs and poisons from biological specimens, and other forensic applications. Recently developed SPME methods are also presented, including the analysis of ignitable liquid residues on human skin, odor signatures, and several drug applications such as free-fraction antipsychotic drug levels, blood alcohol casework, drink-tampering analysis, and gamma-hydroxybutyrate identification without the need for derivatization. SPME is shown to be an inexpensive, rapid, and sensitive method for the analysis of a variety of forensic specimens.     

Recent advances in the applications of forensic science to fire debris analysis

The forensic discipline of ignitable liquid and fire debris analysis is rapidly changing. Refinements in existing methods as well as development of new techniques are changing the routine methods of analysis. Optimization of existing extraction techniques and research into novel methods of extracting debris have improved the recovery of ignitable liquids from debris samples. The application of highly specialized instrumentation to problems of sensitivity and matrix interference has resulted in new ways of performing chemical analyses, allowing for improved limits of detection. Preliminary research in novel approaches to ignitable liquid comparisons is being evaluated, with the hopes of providing more detailed information to the field investigators. Research into a variety of areas related to fire debris analysis is ongoing, and will continue to improve the quality of ignitable liquid residue analysis.     

A Forensic Approach to Evaluate the Effect of Different Matrices and Extraction Solvents for the Identification of Diesel Residue in Simulated Arson by GC–MS

Chromatographia - Investigation of an arson case presents several challenges to the forensic investigator. Identification of the ignitable liquid residues in the fire debris is one of the crucial...     

Study of acidified ignitable liquid residues in fire debris by solid‐phase microextraction with gas chromatography and mass spectrometry

The detection and identification of ignitable liquid residues in fire debris can be meaningful in fire investigations. However, background pyrolysis products and weathering hinder the identification and classification steps. In addition to those processes, the acidification of the ignitable liquids before the combustion process could make those tasks even more difficult. Nevertheless, there are no systematic studies assessing the extraction, analysis, and composition of acidified ignitable liquid residues obtained from fire debris. In this work, a method for the study of acidified ignitable liquid residues in fire debris by solid‐phase microextraction with gas chromatography and mass spectrometry is proposed. This methodology has been evaluated, first with simulated solutions (gasoline/sulfuric acid mixtures set on fire under controlled conditions), and then with analysis of samples from real fire debris obtained from 18 chemical ignition Molotov cocktails made with sulfuric acid and three different ignitable liquids (two types of gasoline and diesel fuel). In addition, the extensive modifications observed in chromatograms of acidified ignitable liquid residues regarding neat and weathered samples were studied. These alterations were produced by the combustion and acidification processes. As a consequence, tert‐butylated compounds are proposed as diagnostic indicators for the identification of acidified gasoline in fire debris, even in strongly weathered samples.     

Application of solid-phase microextraction to the recovery of explosives and ignitable liquid residues from forensic specimens

A current review of the application of solid-phase microextraction (SPME) to the analysis of ignitable liquids and explosive residues is presented along with experimental results demonstrating the relative effects of controllable variables. Variables discussed include fiber chemistry, adsorption and desorption temperatures, extraction and desorption times, fiber sampling placement (direct, headspace, and partial headspace) and matrix effects, including water content. SPME is shown to be an inexpensive, rapid and sensitive method for the analysis of ignitable liquids and high explosives residues from solid debris samples and from aqueous samples. Explosives are readily detected at parts per trillion concentrations and ignitable liquids are reproducibly detected at levels below those using conventional methods.     

Analytical tools for the analysis of fire debris. A review: 2008–2015

The analysis of fire debris evidence might offer crucial information to a forensic investigation, when for instance, there is suspicion of the intentional use of ignitable liquids to initiate a fire. Although the evidence analysis in the laboratory is mainly conducted by a handful of well-established methodologies, during the last eight years several authors proposed noteworthy improvements on these methodologies, suggesting new interesting approaches. This review critically outlines the most up-to-date and suitable tools for the analysis and interpretation of fire debris evidence. The survey about analytical tools covers works published in the 2008–2015 period. It includes sources of consensus-classified reference samples, current standard procedures, new proposals for sample extraction and analysis, and the most novel statistical tools. In addition, this review provides relevant knowledge on the distortion effects of the ignitable liquid chemical fingerprints, which have to be considered during interpretation of results.     

Determination of gasoline and diesel residues on wool,silk, polyester and cotton materials by SPME–GC–MS

The identification of ignitable liquids is very important and challenging aspect in arson crime investigations. The detection of gasoline and diesel fuel components using solid phase micro-extraction prior to gas chromatography–mass spectrometry for the forensic analysis of fire debris has been carried out. Previous works show that the absorption characteristics of the substrate are one of the most important factors in determining the evaporation rate of the accelerants. In order to determine the presence of the fuel residues, four of the most common substrate materials were tested in this work; wool, cotton, silk and polyester. The obtained results indicate that both gasoline and diesel fuel accelerants persisted longer on wool and silk than on the other selected substrates. Such information illustrates the influence of fuel persistence times after extinguishing and the best materials to be scanned for ignitable liquids at the fire scene.     

火灾现场残留物中助燃剂提取及检测方法研究进展

综述了近10年来火灾现场助燃剂残留物的提取及检测方法,并对火场助燃剂残留物的检测进行了展望.     

The effects of microbial degradation on ignitable liquids

The identification of ignitable liquid residues in fire debris is a key finding for determining the cause and origin of a suspicious fire. However, the complex mixtures of organic compounds that comprise ignitable liquids are susceptible to microbiological attack following collection of the sample. Biodegradation can result in selective removal of many of the compounds required for identification of an ignitable liquid. Such degradation has been found to occur rapidly in substrates such as soil, rotting wood, or other organic matter. Furthermore, fire debris evidence must often be stored for extended periods at room temperature prior to analysis due to case backlogs and available evidence storage. Hence, extensive damage to ignitable liquid residues by microbes poses a significant threat to subsequent laboratory work. In this work, the effects of microbial degradation of ignitable liquids in soil have been evaluated as a function of time. Key findings include the loss of n-alkanes, particularly C₉–C₁₆, which showed the most dramatic decrease in gasoline as well as the petroleum distillates, while branched alkanes remained unchanged. Monosubstituted benzenes also showed the most dramatic loss in gasoline. In the heavy petroleum distillates, n-alkanes with even carbon numbers were degraded more than n-alkanes with odd carbon numbers. Figure A “fully involved” house fire in Indianapolis, IN

气相色谱-质谱法在人体气味分析中的应用进展

气相色谱-质谱法（GC-MS）是目前分析人体气味的主要技术手段，其不但可以分析人体气味的组成成分，还可以比较不同个体气味之间的差异。该文首先介绍了人体气味的提取和样品前处理的手段，随后对GC-MS在人体气味的采集及储存、成分分析及差异性研究、用于个体识别和健康表征等方面进行了综述，最后对GC-MS在人体气味分析中的发展趋势进行了展望。