利用扫描电镜/能谱仪和X-射线衍射仪鉴别假“冰毒”

冰毒为纯白或淡黄色结晶体,为利益所驱,很多制贩毒者利用其它外观相似的晶体充当替代品或者掺杂剂,在常规检测时,用气/质联用仪无法检验其成分。本文利用扫描电镜/能谱仪和X-射线衍射仪对外观酷似"冰毒"的晶状物成分进行检测,先利用扫描电镜/能谱仪测定未知物主要元素,再利用X-射线衍射仪测定其晶体结构和成分。两者有效结合成功地鉴别假"冰毒"物质的成分。     

HPLC-DAD双波长法同时测定脑络欣通胶囊中阿魏酸及天麻素含量

目的 建立双波长同时测定脑络欣通胶囊中天麻素和阿魏酸含量的方法,为脑络欣通的质量控制提供依据。 方法 采用高效液相色谱-二极管阵列检测器和Welch Materials C8色谱柱（250 mm×4.6 mm,5 μm）。流动相：乙腈-0.01%磷酸;梯度洗脱（乙腈：0～10 min,6%;10～30 min,6%→35%）;流速：1.0 mL/min;柱温：35 ℃;检测波长：320 nm（阿魏酸）和222 nm（天麻素）。结果 在30 min内,实现了阿魏酸与天麻素双波长同时测定,二者含量分别在0.20～2.39 μg（r＝0.999 9）和0.20～2.41 μg（r＝0.999 8）范围内与峰面积呈现良好的线性关系,平均加样回收率分别为99.5%和99.1%（n＝6）。 结论 双波长检测对复方中阿魏酸与天麻素定量更准确,二者同时测定能有效提高分析效率,该方法可用于脑络欣通胶囊的质量控制。     

高效液相色谱法-蒸发光散射检测器同时测定肝乐颗粒中黄芪甲苷和芍药苷的含量

目的 采用高效液相色谱-蒸发光散射检测器(high performance liquid chromatography-evaporative light scattering detector, HPLC-ELSD)建立肝乐颗粒中黄芪甲苷和芍药苷的含量测定方法。方法 以水和甲醇分别为流动相A和流动相B,在Hypersil ODS XB-C18柱(4.6 mm×250 mm,5 μm)上进行梯度洗脱。洗脱程序：0~5 min,A 60%;6~10 min,A 25%,11~18 min,A 10%;流速：1.2 mL/min;柱温：30 ℃。ELSD参数优化：增益值分别设为1、2、3;漂移管温度分别设为50、70、90、110 ℃;载气流量分别为1.2、1.6、2.0、2.4 L/min。结果 通过优化参数,在增益值为2,漂移管温度为90 ℃和载气流量为2.0 L/min时,对芍药苷和黄芪甲苷的含量检测结果最佳。芍药苷和黄芪甲苷的平均加样回收率分别为99.58%、100.37%,RSD分别为2.32%、1.21%。结论 该方法简便、准确、灵敏度高、重现性好,所优化的ELSD参数及建立的HPLC-ELSD法适合肝乐颗粒中芍药苷和黄芪甲苷含量的同时测定。     

测谎技术及其在我国司法实践中的应用

测谎仪的发明和应用,在犯罪侦查史上是一个重大的突破。现在,测谎技术作为一项通用高科技已被世界上50多个国家广泛应用于国防、司法乃至商业等各个领域。实践证明,测谎技求完全是科学可信的,通过测谎可以准确地鉴别有罪和无罪。近年来,测谎技术正快速和大量地进入了我国司法领域,它作为一种行之有效的辅助侦查手段,为公、检、法、司等机关解决众多疑难案件提供了重要的参考依据,并取得显著效果。为了促进和推广这项技术的应用,本文着重对测谎技术的概念和原理及其在我国司法实践中的应用等方面作较详细的阐述。     

溺死的法医学检验现状及进展

本文概括阐述了近年来,国内外学者将硅藻的检验、内脏异物颗粒和微量元素成分的检验、血液化学的检验、电子显微镜的观察等方法应用于溺死的诊断,试图为溺死的法医学鉴定提供准确的诊断指标。     

Evaluation of the Forensic Utility of Scanning Electron Microscopy‐Energy Dispersive Spectroscopy and Laser Ablation‐Inductively Coupled Plasma‐Mass Spectrometry for Printing Ink Examinations

Improvements in printing technology have exacerbated the problem of document counterfeiting, prompting the need for analytical techniques that better characterize inks for forensic analysis and comparisons. In this study, 319 printing inks (toner, inkjet, offset, and Intaglio) were analyzed directly on the paper substrate using scanning electron microscopy‐energy dispersive spectroscopy (SEM‐EDS) and Laser Ablation‐Inductively Coupled Plasma‐Mass Spectrometry (LA‐ICP‐MS). As anticipated, the high sensitivity of LA‐ICP‐MS pairwise comparisons resulted in excellent discrimination (average of ~ 99.6%) between different ink samples from each of the four ink types and almost 100% correct associations between ink samples known to originate from the same source. SEM‐EDS analysis also resulted in very good discrimination for different toner and intaglio inks (>97%) and 100% correct association for samples from the same source. SEM‐EDS provided complementary information to LA‐ICP‐MS for certain ink types but showed limited utility for the discrimination of inkjet and offset inks.     

扫描电镜/X射线能谱仪检验电流斑规范化方法探讨

目的探讨电流斑皮肤金属化的机理、检材提取处理和扫描电镜/能谱仪检验规范化方法,对检验结果进行分析和价值判断。方法用扫描电镜/能谱检验,采用低倍大窗口覆盖损伤区域采集平均元素能谱图,并在可能的金属元素富集区域寻找球形金属颗粒。结果扫描电镜下可观察到散在的孔穴、细胞碎屑、龟裂、裂隙等特征,有些电流斑可检出金属元素,其中部分电流斑可发现球形金属颗粒。结论采用规范化的检材提取、处理和检验方法可消除随意性方法造成错检的可能。电流斑皮肤上异常含量的金属附着可支持病理检验符合电流斑表现的结论,同时也为电击导体的推断和金属元素成分比对提供依据。球形金属颗粒的发现揭示存在电弧高温的可能性极大,可强力支持病理检验符合电流斑表现的结论。     

SEM and Stereomicroscopic Analysis of Cut Marks in Fresh and Burned Bone

This study documents the prevalence of cut mark characteristics in fresh and burned domestic pig ribs. Stab wounds from single edge serrated and smooth‐edged knives were inflicted in the vertebral and sternal regions of each fresh rib. Each rack of ribs was then divided into vertebral and sternal units. Vertebral units were defleshed and their associated cut marks were examined using a stereomicroscope. Sternal units were burned in an outdoor fire pit and examined with the addition of a scanning electron microscope (SEM). Linear cuts, V‐shaped cross‐sections, mounding, hinge fractures, and wastage were all observed on burned ribs. There was an overall decrease in the prevalence of all features (up to a 40% decrease), regardless of knife type, in burned ribs. Striations within cut marks were not observed in either fresh or burned ribs. Oblique faulting and bone lifts could only be observed using the SEM. Mounding and wastage were obliterated during the burning process. Therefore, cut marks in burned bone should ideally be examined for their characteristics utilizing an SEM.     

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.     

刑事诉讼中的图像电子证据初论

在日常生活和刑事诉讼过程中,电子形式的图像证据已经较为常见。对这种与传统的图像证据截然不同的新型证据形态,需要从证据规则、证明过程等角度进行新的探索。图像电子证据的证明能力和证明力的认定,具有鲜明的技术特征,离不开刑事鉴定和法庭科学的支持。更重要的是,它为传统的证据规则和刑事证明理论提供了新鲜而又充满挑战的内容。