3,4-亚甲二氧基甲卡西酮的鉴定

目的 建立基于傅里叶变换红外光谱(FTIR)、气相色谱-质谱(GC-MS)结合高分辨质谱技术联合鉴定未知样品的方法.方法 未知样品采用红外专用取样器直接检测;甲醇溶解后采用GC-MS和组合型高分辨质谱检测,以MDMA为内标物.结果 未知样品获得的红外光谱特征吸收峰为1679(C=O键),1603,1502,1453,1423,1259,1121,1090,1035,930,887,838,768,742和717cm-1,质谱特征碎片峰(m/z)为58.1,91.0,120.9,149.0和207.0,测得的精确质量数[M+H]+为208.0966.经信息分析未知样品鉴定为3,4-亚甲二氧基甲卡西酮,该物质属于新型化学合成卡西酮类精神活性物质,已经列入部分欧盟国家的管制药物目录.结论 本方法可用于3,4-亚甲二氧基甲卡西酮的鉴定.     

Analysis and Discrimination of Single‐Layer White Architectural Paint Samples,

Comparative analyses of 50 single‐layer white architectural paints were conducted to determine the discrimination power using standard techniques and to provide a basis for assessing significance when paints with limited features are not discriminated. Utilizing Fourier transform infrared spectroscopy (FTIR), 68 undifferentiated pairs resulted, yielding a discrimination of 94.45%. Adding stereomicroscopy, scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) and backscatter electron (BSE) imaging, and pyrolysis‐gas chromatography/mass spectrometry (Py‐GC/MS), the overall discrimination was 99.35%. The study included blind verification replicates, which resulted in the only pairs without indications of physical or chemical differences. The remaining groups of undifferentiated samples contained subtle differences by at least one technique, but were considered undifferentiated for the discrimination power evaluations. This study demonstrates a high degree of discrimination of single‐layer white architectural paints using methods of analysis often encountered in forensic science laboratories.     

The Survival of Gunshot Residues in Cremated Bone: An Inductively Coupled Plasma Optical Emission Spectrometry Study

Gunshot residue (GSR) has been sought and demonstrated on many types of material and with many techniques. Inductively coupled plasma optical emission spectrometry (ICP‐OES) could be a useful method on difficult substrates, but a systematic study on burnt material has never been performed. Hence, this study aims at evaluating the usefulness and reliability of this method on burnt samples. Sixteen adult bovine ribs (eight with soft tissues, eight totally skeletonized) were shot using two kinds of projectile (both 9 mm full metal‐jacketed or unjacketed). Then, every sample was led to complete calcination in an electric oven. The area of the gunshot entrance wound was swabbed and analyzed by ICP‐OES; the results were also correlated with a previously published parallel study by scanning electron microscopy (SEM) equipped with an SEM–energy dispersive X‐ray analyzer. ICP‐OES proved to be very sensitive and reliable even on degraded material and can be an appropriate nondestructive method for detecting residues on difficult and delicate substrates such as burnt bone.     

Optimizing Accu Time‐of‐Flight/Direct Analysis in Real Time for Explosive Residue Analysis

The use of a direct analysis in real time (DART) mass spectrometer (MS) instrument was optimized for 22 compounds of organic explosive residues to provide a guide for DART‐MS users in rapid screening of explosive compounds. Samples were introduced as neat solutions and sequential dilutions to determine optimal instrument conditions and lowest concentration detectable. Most compounds were optimized to 250°C in the negative ion mode, and several compounds benefited from the addition of a chloride dopant from methylene chloride (amino‐dinitrotoluenes, RDX, EGDN, and PETN). Few compounds were more sensitive in the positive ion mode (TEGDN, DEGDN, HNS, and DMNB). Mixtures of compounds were detected using clean room wipes, directly from their surfaces and from subsequent extractions. Compounds from the mixtures were also successfully detected in soil and from swipes of spiked surfaces. The instrument showed merit in detection of pg/μL solutions for most of the compounds and among the substrates tested.     

SPE-GC/MS 法分析鱼塘水中的5种农药

目的：建立鱼类中毒案件中鱼塘水5种农药的固相萃取（solid phase extraction,SPE）结合气相色谱－质谱联用仪（GC/MS）的检测方法。方法比较 Oasis HLB cartridge、Bond Elut C18和 SampliQ C183种固相萃取柱提取、净化鱼塘水中5种农药的提取回收率,并考察洗脱剂种类、洗脱剂用量对提取回收率的影响。结果利用 Bond Elut C18固相萃取柱,以3mL 苯作为洗脱剂,鱼塘水中5种农药质量浓度在1~50μg/mL范围内有良好的线性关系,相关系数为0．9962~0．9996,测得的检出限为3．4~26μg/L,提取回收率为61．49%~102．48%,相对标准偏差均≤3．01%。结论 SPE－GC/MS 法灵敏度高、准确度和精密度好,简单快速,溶剂消耗量少,适用于鱼塘水中5种农药的检测。     

Chemical Contamination of Soft Drinks in Sealed Plastic Bottles by Environmental Stress Cracking

Abstract:  A contamination of soft drinks in sealed bottles by organic solvents is reported: closed bottles full of soft drinks were accidentally placed on a cardboard soaked with thinner and the organic fluid subsequently fissured the bottom of the bottles and penetrated into the soft drinks without any apparent leakage of the soft drinks. Experiments were carried out to simulate the process: the penetration of different organic solvents into soft drinks through the bottom of closed bottles was tested. The penetration occurred only when the closed bottles contained carbonated soft drinks (CSD), indicating that inner pressure is a necessary condition for the fissuring of the bottles. This paper discusses environmental stress cracking of polyethylene terephthalate (PET) bottles by organic solvents and migration of chemicals to CSD. Experiments were conducted to determine the conditions in which PET can be permeable to poisoning organic products.     

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.     

Proteolytic‐Based Method for the Identification of Human Growth Hormone*

Abstract: Human growth hormone (HGH) is a relatively small protein consisting of 191 amino acids and has an average mass of 22,125 amu. The forensic analysis of proteins such as HGH must meet the analytical sufficiency requirements for the laboratory and consists of a binary approach. A suspected sample is analyzed as the whole protein for retention time and mass determination using high performance liquid chromatography equipped with a photodiode array and liquid chromatography mass spectrometry. Further fragmentation of the protein using a proteolytic enzyme adds another dimension to the specificity of the analysis. Porcine trypsin digests proteins in a very predictable manner and yields peptide fragments of the original protein that can be used as a means for fingerprinting the larger biomolecule. In silico, or theoretical, digestion of HGH by trypsin yields 21 peptides ranging in size from 1 to 23 amino acids in length. The larger fragments containing higher numbers of amino acids give more specificity to identifying a protein based on a fragment produced by the digestion of trypsin. Herein, the analysis of HGH using a proteolytic approach is presented that meets the Scientific Working Group for the Analysis of Seized Drugs (SWGDRUG) recommendations for the identification of unknown substances.     

Trace Elemental Analysis of Titanium Dioxide Pigments and Automotive White Paint Fragments for Forensic Examination Using High‐Energy Synchrotron Radiation X‐Ray Fluorescence Spectrometry*

Abstract: High‐energy synchrotron radiation x‐ray fluorescence spectrometry (SR‐XRF) utilizing 116 keV x‐rays was used to characterize titanium dioxide pigments (rutile) and automotive white paint fragments for forensic examination. The technique allowed analysis of K lines of 9 trace elements in 18 titanium dioxide pigments (rutile), and 10 trace elements in finish coat layers of seven automotive white paint fragments. High‐field strength elements (HFSE) were found to strongly reflect the origin of the titanium dioxide (TiO₂) pigments, and could be used as effective parameters for discrimination and classification of the pigments and paint fragments. A pairwise comparison of the finish coat layers of seven automotive white paint fragments was performed. The trace elements in the finish coat layers detected by the high‐energy SR‐XRF were especially effective for identification. By introducing the trace element information of primer and electrocoat layers, all the automotive white paint fragments could be discriminated by this technique.     

氯硝安定在生物体内的代谢

目的推测氯硝安定在生物体内的主要代谢方式,检测其代谢产物。方法取5只Wistar大鼠,连续3d给每只大鼠灌胃氯硝安定（剂量分别为1、2、2mg）,收集灌胃后24h内尿液;给3只大鼠各灌胃2mg氯硝安定,2h后处死,取血液和肝组织等检材;收集3名口服5mg氯硝安定的志愿者24h内尿液。分别对不同检材进行处理后,气相色谱/质谱联用（GC/MS）检测。结果在大鼠阳性尿液和志愿者阳性尿液中,均检出7-乙酰氨基氯硝安定和7-氨基氯硝基安定;在大鼠血液中,主要检出氯硝安定和7-氨基氯硝基安定;在大鼠肝组织中,主要检出7-乙酰氨基氯硝安定,还有少量7-氨基氯硝安定和氯硝安定。结论氯硝安定进入生物体后,其7位硝基被还原为氨基,氨基接着被乙酰化,形成7-氨基氯硝基安定和7-乙酰氨基氯硝安定代谢物,其中7-乙酰氨基氯硝安定为主要代谢物。