微波消解-扫描电镜联用法在溺死诊断中的应用

目的探讨微波消解-扫描电镜联用法在溺死诊断中的应用价值。方法收集已知死因的尸体标本105例,其中水中尸体85例(生前溺死70例,死后抛尸入水15例),陆地自然死亡尸体20例。水中死亡案例同时收集落水处水样。分别用微波消解-扫描电镜联用法(方法 A)和硝酸破机-光镜联用法(方法 B)对上述尸体的离体肺、肝、肾、骨髓组织及水样进行硅藻定性、定量检测。结果①溺死尸体的肺、肝、肾、骨髓中及落水处水样硅藻检出率:A法分别为100%、94.3%、92.9%、82.9%、100%,硅藻检验阳性率为100%;B法分别为90%、62.9%、51.4%、28.6%、92.9%,硅藻检验阳性率为65.7%。②两种方法检出的硅藻种类与落水处水样中硅藻的种类均一致。③两种方法在死后入水尸体离体的肺中也检出少量硅藻(<3个/2g肺组织),但在死后入水尸体的其它脏器及陆地自然死亡尸体脏器中均未检出硅藻。结论微波消解-扫描电镜联用法较硝酸破机-光镜联用法对尸体离体组织脏器中的硅藻检出率高,方法灵敏,定性准确。     

3个道地产区黄芪中钙、镁、锌、铁、铜、锰含量测定

目的 测定3个道地产区黄芪中钙(Ca)、镁(Mg)、锌(Zn)、铁(Fe)、铜(Cu)、锰(Mn)的含量,以探讨道地药材与微量元素的相关性。方法 采用硝酸-过氧化氢（体积比5〖DK〗∶2）体系微波消解黄芪样品,火焰原子吸收光谱法测定黄芪中Ca、Mg、Zn、Fe、Cu、Mn的含量。结果 内蒙古黄芪除Cu元素含量稍低于山西黄芪之外,Ca、Mg、Zn、Fe、Mn元素含量都高于甘肃黄芪和山西黄芪;山西黄芪除Zn元素含量不低于甘肃黄芪之外,Ca、Mg、Fe、Cu、Mn元素含量都低于甘肃黄芪。结论 在内蒙古、甘肃、山西3个道地产区黄芪中,人体必需微量元素含量以内蒙古黄芪最优,甘肃黄芪次之,山西黄芪再次之。     

Determination of Trace Elemental Concentrations in Document Papers for Forensic Comparison Using Inductively Coupled Plasma–Mass Spectrometry

Abstract:  With improvements in manufacturing procedures, comparing physical characteristics of paper samples may not offer sufficient discrimination among different vendors. In this work, the potential to differentiate paper samples based on trace element concentrations was investigated. Paper samples from two different vendors were microwave-digested and trace element concentrations (Mg, Al, Mn, Fe, Sr, Y, Ba, Ce, and Nd) were determined using inductively coupled plasma–mass spectrometry. Differences in concentration were assessed statistically using two-way ANOVA and Tukey's honestly significant differences test. Elemental concentrations were shown to be consistent across a single sheet as well as within a single ream of paper for each vendor. Reams from vendor A were differentiated based on Al and Ba concentration while reams from vendor B were differentiated based on Mg, Mn, and Sr concentrations. Paper was differentiated according to vendor based on significant differences in Ba, Sr, Ce, and Nd concentrations.     

The problem of DNA contamination in forensic case work—How to get rid of unwanted DNA?

The PCR technique has become a powerful and very sensitive tool in a broad field of research, that is, molecular biology, medical diagnostics, population genetics, ancient DNA analysis and forensic casework.However, the high sensitivity down to single molecules can easily cause false-positive PCR results due to different types of contamination. In this study, artificial DNA contaminations (saliva and pure DNA) were treated with UV irradiation and other decontamination procedures. A satisfactory DNA removal could not be achieved, emphasizing the necessity of contamination avoidance.     

Development of microwave-assisted extraction procedure for organic impurity profiling of seized 3,4-methylenedioxymethamphetamine (MDMA)

Abstract: Organic impurity profiling of seized 3,4‐methylenedioxymethamphetamine (MDMA) tablets aims to link tablets to common production sources. Conventionally, organic impurities are extracted from tablets using a liquid–liquid extraction (LLE) procedure prior to analysis by gas chromatography–mass spectrometry (GC‐MS). In this research, the development of an alternative microwave‐assisted extraction/headspace solid‐phase microextraction (MAE/HS‐SPME) procedure is described. The optimal procedure used phosphate buffer (1 M, pH 8), with an HS‐SPME extraction temperature of 70°C for 40 min, using a divinylbenzene/Carboxen?/polydimethylsiloxane (DVB/CAR/PDMS) fiber. Impurities were extracted from seized MDMA exhibits using the MAE/HS‐SPME procedure, as well as HS‐SPME alone, and a conventional LLE procedure. The HS‐SPME procedure was deemed to be the most practical because of the affordability and need for less analyst involvement. Although the LLE was limited in the number of impurities extracted, the procedure is still useful for the extraction of less volatile impurities that are not extracted by HS‐SPME.     

微波消解ICP-MS法测定人头发中24种元素的含量

目的建立人头发中24种无机元素的电感耦合等离子体质谱（inductively coupled plasma-mass spec-trometry,ICP-MS）分析方法。方法采用微波消解法处理样品,以铟（115In）作内标,用ICP-MS分析人头发中的24种元素含量。同时检测56例健康志愿者和10例海洛因滥用者头发中24种元素含量。结果 24种元素的方法检出限范围为0.0003~10.14μg/g,标准物质的测得值与标准值基本相符。海洛因滥用者经戒毒治疗后头发中镁、镓、钡含量下降。结论该方法灵敏度、准确度高,适用于头发中24种元素的测定。     

尿液中铊的微波消解ICP／AES标准加入测定法

目的建立尿液的微波消解和金属毒物铊的ICP／AES标准加入分析方法。方法取1．0mL尿样于聚四氟乙烯消解管中,加入3mL浓硝酸和0．5mL双氧水,进行微波消解。冷却后,用2％的硝酸定容至10．0mL。根据标准加入法进行ICP／AES定量分析。结果回收率为101．5％,检出限为2．6ng／mL,线性范围为0．05ug／mL～2．0ug／mL。结论该方法操作简便,回收率高,检出限低,可多元素同时测定,结果可靠。     

微波提取山茱萸马钱素的工艺研究W

以山茱萸为原料，在微波场的作用下，进行了不同微波提取溶剂、料液比、提取时间、提取温度、提取功率和正交优化实验对山茱萸中马钱素提取率的影响研究。结果表明：影响微波提取的因素依次为提取时间、提取温度、提取功率。优选方案为：微波提取溶剂为水，料液比1∶30，提取时间10min, 提取温度70℃，提取功率300W,山茱萸马钱素提取率为0.80%。     

微波照射在衍生化反应中的应用

介绍了用微波照射技术快速制备吗啡、苯丙胺类的乙酰、三氟乙酰、五氟丙酰、七氟丁酰、MSTFA衍生物方法。常规加热方法制备这些衍生物需在60～70℃反应30min,而使用微波照射（~400W,仅需2～3min即可完成．二种方法所得的衍生物气相保留时间和质谱碎片相同．     

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.