Fast gas chromatography of explosive compounds using a pulsed-discharge electron capture detector

The detection of a mixture of nine explosive compounds, including nitrate esters, nitroaromatics, and a nitramine in less than 140 sec is described. The new method employs a commercially available pulsed-discharge electron capture detector (PDECD) coupled with a microbore capillary gas chromatography (GC) column in a standard GC oven to achieve on-column detection limits between 5 and 72 fg for the nine explosives studied. The PDECD has the benefit that it uses a pulsed plasma to generate the standing electron current instead of a radioactive source. The fast separation time limits on-column degradation of the thermally labile compounds and decreases the peak widths, which results in larger peak intensities and a concomitant improvement in detection limits. The combination of short analysis time and low detection limits make this method a potential candidate for screening large numbers of samples that have been prepared using techniques such as liquid-liquid extraction or solid-phase microextraction.     

毒鼠强中毒实质性器官组织超微病理变化研究

目的观察不同浓度毒鼠强中毒大鼠实质性器官的超微病理变化。方法采用灌胃方法使大鼠毒鼠强染毒,制作大鼠中毒模型,并以健康大鼠灌服生理盐水为对照,提取大鼠的脑皮质、脑干桥脑部、心、肝、脾、肾等实质性器官,进行超微病理观察。结果不同浓度的毒鼠强可对心肌细胞、脑神经细胞、神经纤维和肝细胞造成一定损伤,而对肾、脾组织细胞损伤不明显。脑皮质神经元细胞结构模糊,内质网轻度扩张,线粒体扩张水肿,且无明显的剂量-反应关系;脑干桥脑部可见多处弥散性软化灶,神经细胞核溶解,神经纤维细胞有坏死,血管内皮细胞肿胀,血管周围有间隙出现,脑干损伤有明显的剂量-反应关系;心肌细胞表现为不同程度的心肌细胞坏死、线粒体弥漫性崩解或肿胀、肌丝断裂溶解、肌溶灶普遍存在等变化,并呈现出明显的剂量-效应关系;肝细胞表现弥漫性肿胀,细胞模糊,肝窦狭小,内皮细胞肿胀,结构模糊不清,细胞质内线粒体明显肿胀,糖原含量减少,与中毒剂量和时间均呈明显相关性。结论脑、心、肝可能为其毒性作用的主要靶器官或靶组织。     

对签字笔墨水的分析回顾及展望

文章叙述了目前国内外签字笔墨水的发展及主要成分,并介绍了分析签字笔墨水的方法。通过化学法和TLC法可以确定签字笔墨水是水性还是中性;利用GC／MS法可以确定签字笔墨水中溶荆成分及其变化;利用拉曼光谱法可以鉴别墨水中染料或颜料成分;利用红外反射法可将29种墨水分为三类;利用扫描电镜法可以通过颜料形态的差别鉴别颜料基墨水。     

微观视角下湿度对粉末显现手印影响规律探究

目的微观视角下探究湿度对粉末显现手印的影响规律。方法利用扫描电镜微观成像技术,观察分析不同湿度下粉末的微观形态、粉末显现不同湿度下手印的微观形态、粉末显现不同方法处理高湿度手印的微观形态。结果黑磁粉、金粉、银粉分别在相对湿度50%、30%、50%时开始出现吸湿结球现象,随湿度增加,粉末吸湿结球程度加剧,且三种粉末中金粉和银粉的吸湿结球程度最为严重;对不同湿度下手印显现,黑磁粉从相对湿度50%(金粉为30%、银粉为50%)的手印开始,随湿度增加,手印乳突花纹和小犁沟位置处粉末颗粒增多,纹线模糊,乳突纹线与小犁沟难以分辨,三种粉末中黑磁粉显现手印的纹线清晰程度最高;95%湿度下手印经在50%相对湿度环境中静置4h或吹风机吹干10min后进行粉末显现,纹线变清晰。结论1)湿度对粉末和手印都有影响,其中黑磁粉显现手印适用湿度范围为相对湿度50%以下(金粉为30%以下、银粉为50%以下);湿度影响程度排序:金粉>银粉>黑磁粉;2)降低手印所处环境湿度、加快手印表面空气流通均可减弱高湿度对粉末显现的影响。     

A Case of Contested Cremains Analyzed Through Metric and Chemical Comparison

Since the 1980s, cremation has become the fastest growing area of the U.S. funeral industry. At the same time, the number of litigations against funeral homes and cremation facilities has increased. Forensic anthropologists are often asked to determine whether the contents of an urn are actually cremated bone, and to address questions regarding the identity of the remains. This study uses both metric and chemical analyses for resolving a case of contested cremains. A cremains weight of 2021.8 g was predicted based on the decedent's reported stature and weight. However, the urn contents weighed 4173.5 g. The urn contents also contained material inconsistent with cremains (e.g., moist sediment, stones, ferrous metal). Analysis using XRD and SEM demonstrated that the urn contained thermally altered bone as well as inorganic material consistent with glass fiber cement. Although forensically challenging, cremains cases such as this one can be resolved using a multidisciplinary approach.     

Chemical Differentiation of Osseous and Nonosseous Materials Using Scanning Electron Microscopy–Energy-Dispersive X-Ray Spectrometry and Multivariate Statistical Analysis

Identification of osseous materials is generally established on gross anatomical features. However, highly fragmented or taphonomically altered materials may be problematic and may require chemical analysis. This research was designed to assess the use of scanning electron microscopy–energy-dispersive X-ray spectrometry (SEM/EDX), elemental analysis, and multivariate statistical analysis (principal component analysis) for discrimination of osseous and nonosseous materials of similar chemical composition. Sixty samples consisting of osseous (human and nonhuman bone and dental) and non-osseous samples were assessed. After outliers were removed a high overall correct classification of 97.97% was achieved, with 99.86% correct classification for osseous materials. In addition, a blind study was conducted using 20 samples to assess the applicability for using this method to classify unknown materials. All of the blind study samples were correctly classified resulting in 100% correct classification, further demonstrating the efficiency of SEM/EDX and statistical analysis for differentiation of osseous and nonosseous materials.     

Scanning Electron Microscope Analysis of Gunshot Defects to Bone: An Underutilized Source of Information on Ballistic Trauma

Recent years have seen increasing involvement by forensic anthropologists in the interpretation of skeletal trauma. With regard to ballistic injuries, there is now a large literature detailing gross features of such trauma; however, less attention has been given to microscopic characteristics. This article presents analysis of experimentally induced gunshot trauma in animal bone (Bos taurus scapulae) using full metal jacket (FMJ), soft point (SP), and captive bolt projectiles. The results were examined using scanning electron microscopy (SEM). Additional analysis was conducted on a purported parietal gunshot lesion in a human cranial specimen. A range of features was observed in these samples suggesting that fibrolamellar bone response to projectile impact is analogous to that observed in synthetic composite laminates. The results indicate that direction of bullet travel can be discerned microscopically even when it is ambiguous on gross examination. It was also possible to distinguish SP from FMJ lesions. SEM analysis is therefore recommended as a previously underexploited tool in the analysis of ballistic trauma.     

高效液相色谱-蒸发光散射法检测芪白平肺胶囊中3种人参皂苷含量

目的 采用高效液相色谱仪-蒸发光散射检测器(high performance liquid chromatography-evaporative light scattering detector, HPLC-ELSD)建立芪白平肺胶囊中人参皂苷Rg1、Re和Rb1的含量测定方法。方法 采用色谱柱为Hypersil ODS XB-C8柱(4.6 mm×250 mm,5 μm)和Hypersil ODS XB-C18柱(4.6 mm×250 mm,5 μm),以乙腈为流动相A、以水为流动相B进行梯度洗脱;洗脱程序(0～40 min,A 19%;40～55 min,A 19%～40%),流速为1.2 ml/min,柱温为30 ℃。ELSD参数优化：漂移管温度分别设为50、70、90、110 ℃,载气流量分别为1.0、1.2、1.4、1.6 L/min。结果 通过对比研究,最终采用Hypersil ODS XB-C8柱作为分析柱,漂移管温度为90 ℃,载气流量为1.2 L/min时,3种人参皂苷的含量检测结果最佳。人参皂苷Rg1、Re和Rb1的加样回收率分别为98.3%、99.1%、101.8%,RSD分别为0.67%、1.03%、1.22%。结论 所选择的色谱柱和优化的ELSD参数可准确测定芪白平肺胶囊中3种人参皂苷的含量,且重现性好。     

高效液相色谱-蒸发光散射法测定黄芪中单糖和双糖的含量

目的 采用高效液相色谱-蒸发光散射法建立黄芪中单糖和双糖含量的测定方法。方法 色谱柱为Waters X BridgeTM氨基柱（250 mm×4.6 mm,5 μm）,流动相为乙腈-水（70∶30）,流速为1.0 mL/min,柱温为30 ℃。蒸发光散射检测器参数：雾化器温度为50 ℃,漂移管温度为90 ℃,气体流量为1.60 L/min,增益值为1.0。结果 果糖、蔗糖和麦芽糖分别在0.10~0.90 μg（r=0.999 9）、1.00~9.00 μg（r=0.999 6）、0.25~2.25 μg（r=0.999 4）范围内其对数值与峰面积的对数值呈良好的线性关系;平均回收率分别为97.97%（RSD=1.56%）、97.82%（RSD=1.53%）、97.36%（RSD=1.59%）。结论 所建立的高效液相色谱-蒸发光散射法简单、准确、重复性好,可用于黄芪中单糖和双糖的含量测定。     

高效液相-二极管阵列法检测当归芍药散中主要化学成分

［摘要］目的 定性分析中药复方当归芍药散中的主要化学成分。方法 采用高相液相 二极管阵列检测法（high performance liquid chromatography-diode array detector, HPLC-DAD），色谱柱为Welchrom XB C18 (250 mm×4.6 mm，5 μm)，流动相为乙腈-0.05%磷酸水溶液（梯度洗脱）。二极管阵列扫描范围：200~400 nm。结果 通过实验并与已有文献的比较，利用HPLC-DAD检测后的三维图谱可找出中药复方当归芍药散中所含的主要化学成分川芎嗪、芍药内酯苷、芍药苷、阿魏酸、白术内酯Ⅰ、藁本内酯、23-乙酰泽泻醇B醋酸酯等。结论 HPLC-DAD可以对当归芍药散中主要化学成分做出准确定性，为其药效学研究提供依据。