Persistence of Polydimethylsiloxane Condom Lubricants

Polydimethylsiloxane (PDMS) is commonly used to lubricate condoms. The detection of PDMS on swabs from complainants can be used to support an allegation of sexual assault. Previous research has focused on establishing analytical techniques for detecting PDMS. This research examined the persistence of PDMS on the penis, in the vagina, in the mouth, and on skin. The longest PDMS detection times were 20 h on the penis, 35 h in the vagina, and 52 h on skin. PDMS was detected up to 4 h in the mouth if the participant did not eat or drink and up to 9 h if the participant slept. PDMS was not detected in the mouth after eating or drinking. The presence of biological fluids had no detrimental effect on the analysis. Aqueous extraction of swabs for DNA did not remove any significant amount of PDMS; hence, swab remains could be subsequently analyzed for PDMS.     

Citrate Content of Bone as a Measure of Postmortem Interval: An External Validation Study

The postmortem interval (PMI) of skeletal remains is a crucial piece of information that can help establish the time dimension in criminal cases. Unfortunately, the accurate and reliable determination of PMI from bone continues to evade forensic investigators despite concerted efforts over the past decades to develop suitable qualitative and quantitative methods. A relatively new PMI method based on the analysis of citrate content of bone was developed by Schwarcz et al. The main objective of our research was to determine whether this work could be externally validated. Thirty‐one bone samples were obtained from the Forensic Anthropology Center, University of Tennessee, Knoxville, and the Onondaga County Medical Examiner's Office. Results from analyzing samples with PMI greater than 2 years suggest that the hypothetical relationship between the citrate content of bone and PMI is much weaker than reported. It was also observed that the average absolute error between the PMI value estimated using the equation proposed by Schwarcz et al. and the actual (“true”) PMI of the sample was negative indicating an underestimation in PMI. These findings are identical to those reported by Kanz et al. Despite these results this method may still serve as a technique to sort ancient from more recent skeletal cases, after further, similar validation studies have been conducted.     

Toxicological Analysis of Opiates from Alternative Matrices Collected from an Exhumed Body

In this case study, the body of a 45‐year‐old man was exhumed after 1 year at the request of the public prosecutor to assess whether the death was caused by drug consumption. Toxicological analyses were performed on several matrices, including liver, kidney, and the alternative matrices hair and teeth. The systematic toxicological analysis (STA), which consisted of basic and acid liquid/liquid extraction and gas chromatography–mass spectrometry (GC‐MS) analysis, showed the presence of opiates in each of the matrices analyzed. Subsequently, to confirm and quantify the presence of opioids, samples of each of the matrices were subjected to solid‐phase extraction and specific GC‐MS analysis. The case presented demonstrates the possibility of drug detection in an exhumed body that has been buried for 1 year, despite the problems of quantitative interpretation of the data, and that toxicological results could be useful along with other forensic evidence.     

Profiling the scent of weathered training aids for blood-detection dogs

At outdoor crime scenes, cadaver-detection and blood-detection dogs may be tasked with locating blood that is days, weeks or months old. Although it is known that the odour profile of blood will change during this time, it is currently unknown how the profile changes when exposed to the environment. Such variables must be studied in order to understand when the odour profile is no longer detectable by the scent-detection dogs and other crime scene tools should be implemented. In this study, blood was deposited onto concrete and varnished wood surfaces and weathered in an outdoor environment over a three-month period. Headspace samples were collected using solid phase microextraction (SPME) and analysed using comprehensive two-dimensional gas chromatography – time-of-flight mass spectrometry (GC×GC–TOFMS). The chemical odour profiles were compared with the behavioural responses of cadaver-detection and blood-detection dogs during training. Data interpretation using principal component analysis (PCA) and hierarchical cluster analysis (HCA) established that the blood odour could no longer be detected using SPME–GC×GC–TOFMS after two months of weathering on both surfaces. Conversely, the blood-detection dogs had difficulty locating the blood samples after one month of weathering on concrete and after one week of weathering on varnished wood. The scent-detection dogs evaluated herein had not been previously exposed to environmentally weathered blood samples during training. Given that this study was conducted to test the dogs' baseline abilities, it is expected that with repeated exposure, the dogs' capabilities would likely improve. The knowledge gained from this study can assist in providing law enforcement with more accurate training aids for blood-detection dogs and can improve their efficiency when deployed to outdoor crime scenes.     

顶空进样- 气相色谱- 质谱联用法检测3年陈艾条燃烧产物中挥发性成分

目的 运用气相色谱- 质谱联用法对3年陈艾条燃烧产物中的挥发性成分进行比较分析。方法 采用顶空进样- 气相色谱- 质谱联用技术,并通过所用质谱库(NIST 11.L)检索研究其挥发性化学成分组成,用面积归一化法确定各成分的相对百分含量。结果 共分辨出87个色谱峰,鉴定出54个化学成分,约占总挥发性成分含量的88.505%,主要挥发性成分为苯酚(17.448%)、邻- 异丙基苯(5.369%)、乙酰胺(4.957%)、对二甲苯(3.527%)、3- 甲基丁酸(3.001%)等。结论 所建立的方法分离效果较好,所鉴定组分较准确,能够较全面反映出艾烟中主要挥发性成分。     

LC-MS/MS鉴定大鼠血浆中桃红四物汤有效成分

目的 研究桃红四物汤有效成分体内作用的物质基础。方法 利用液相色谱-串联质谱（liquid chromatography technique coupled with tandem mass spectrometry,LC-MS/MS）提供的色谱及离子碎片信息,对大鼠灌胃桃红四物汤中入血成分进行分析鉴定。结果 通过保留时间比对、离子碎片解析等综合分析,鉴定桃红四物汤中6个入血成分（梓醇、藁本内酯、阿魏酸、芍药苷、芍药内酯苷和苦杏仁苷）均为原形成分,入血成分可能为桃红四物汤体内直接作用的有效成分。结论 本实验确定了桃红四物汤经口服后可被胃肠道吸收入血的6个有效成分,为后期桃红四物汤的药物代谢动力学研究提供了参考依据。     

基于超高效液相色谱-高分辨质谱联用技术研究苦参醇提物致大鼠肝毒性的尿液代谢组

目的 观察苦参醇提物（Sophora flavescens alcohol extract,SFAE）对大鼠尿液代谢轮廓的影响,探讨SFAE可能的肝毒性机制。方法 将雄性SD大鼠分为3组,每组6只,分别灌胃给予SFAE 0、1.25、2.5 g/kg,14 d后,采用超高效液相色谱-高分辨质谱（ultra-performance liquid chromatography-high resolution mass spectrometry,UPLC-HRMS）检测大鼠尿液中代谢物的变化。采用主成分分析（principal components analysis,PCA）和正交偏最小二乘法判别分析（orthogonal partial least squares discriminant analysis,OPLS-DA）对组间代谢物进行多元统计分析,筛选潜在的生物标志物,并分析相关的代谢通路。结果 3组大鼠尿液中代谢物在14 d后得到很好的区分,发现并鉴定出15个主要的差异代谢物,其中N6,N6,N6-三甲基-L-赖氨酸、胆酸、甘氨胆酸、脱氧胆酸、马尿酸和肌酸与肝脏毒性关系密切,二氢鞘氨醇和酮戊二酸表达水平降低,其余13种差异代谢物表达水平升高,苦参主要干扰大鼠体内胆汁酸代谢、能量代谢和氨基酸代谢等代谢通路。结论 SFAE对大鼠产生肝毒性,且肝毒性与给药剂量呈正相关。     

向天果脂肪酸成分的气相色谱-质谱分析

目的 测定向天果中石油醚浸提物的成分。方法 采用石油醚冷浸法提取向天果的脂肪酸类成分,甲酯化后,运用气相色谱-质谱联用技术测定其化学成分,在wiley7n.L质谱数据库中鉴定质谱图。结果 经鉴定出16种成分,占总成分的99.70%。结论 向天果中脂肪酸的主要化学成分为9,12-十八碳二烯酸、8-十八碳烯酸、9,12,15-十八碳三烯酸、十八烷酸等     

茯苓不同部位16种元素分布规律研究

目的 测定茯苓的白茯苓、赤茯苓及茯苓皮3个部位的16种微量元素含量,分析茯苓不同部位元素分布规律.方法 采用微波消解-电感耦合等离子体质谱测定茯苓不同部位16种元素的含量,并对其进行非参数检验、因子分析及相关性分析.结果 大部分元素在茯苓皮中含量较高;不同部位中V、Cr、Mn、Fe、Zn、Rb、Sr、Mo、Cd、Cs、Ba、Pb元素含量差异具有统计学意义(P<0.05),Co、Ni、Cu、As含量差异无统计学意义(P>0.05);Cu、Cd、Zn、Ba元素是茯苓3个部位的特征性元素;大多数元素含量之间存在正相关关系(P<0.05).结论 茯苓不同部位对不同元素的吸收具有一定的选择性,不同部位的元素之间存在相关性.     

复方苦参注射液生物碱类成分及血中移行成分的分析

目的 利用超高效液相色谱—电喷雾离子化—四极杆飞行时间质谱（ultra-high-performance liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry,UHPLC-ESI-QTOF/MS）结合UNIFI构建靶向筛查策略分析复方苦参注射液（Compound Kushen Injection,CKI）的生物碱类成分及血中移行成分。方法 首先,采用ESI-QTOF/MS的全信息串联质谱技术采集经UHPLC分离的CKI样品及其空白样品、CKI给药后的大鼠血浆样品及空白血浆样品的信息;然后,建立CKI生物碱化学成分数据库,与MSE数据一同导入UNIFI进行靶向筛查;依据母离子、碎片离子的精确质量对筛查出的化合物进行识别;最后,使用MassLynx 4.1工作站对UNIFI输出的结果进行核实。结果 本实验共分离、鉴定了20种CKI生物碱,其中17种生物碱能在大鼠血浆中被检出。结论 该方法能够快速分析CKI生物碱类成分及其血中移行成分,可为CKI的质量控制及药效物质研究提供参考。