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871.
基体辅助激光解吸电离飞行时间质谱鉴别乌头的研究 总被引：2，自引：0，他引：2
目的建立乌头类中药鉴别的基体辅助激光解吸电离飞行时间质谱方法。方法以DHB为基体,优化飞行时间质谱分析条件,对不同种类的乌头类中药进行飞行时间质谱分析,找出乌头类的指纹峰。结果通过比较炮制乌头与生乌头质谱指纹峰的差异,可作出乌头类是否经炮制的判断。结论基体辅助激光解吸电离飞行时间质谱用于乌头类中药的定性鉴别,分析方法灵敏、准确、快速。 相似文献
872.
现代传媒已经构成了无缝隙、零距离的信息网络,对青少年形成新的价值观、学习社会规范、完成社会化起着潜移默化的引导作用。现代传媒作为社会政治、经济、文化的载体,对青少年思想道德建设的影响是全方位的、不可替代的。部分青少年学术期刊由于缺乏创新意识与竞争意识,存在趋同化、平庸化倾向。 相似文献
873.
Pedro Bertolucci Keese; 《The Howard Journal of Crime and Justice》2024,63(2):166-181
This article analyses mass incarceration in Brazil and how the ongoing ‘war on drugs’ results in punitive dynamics involving the police and the judiciary, leading to the imprisonment of residents of poor neighbourhoods. I argue that the war on drugs intensifies the criminalisation of stigmatised and impoverished territories, extending beyond individual cases. In section 2, drawing on research from the United States and Brazil, I explore the key aspects of the spatial concentration of incarceration in both countries. In section 3, I focus on the specific dynamics of the war on drugs in Brazil, encompassing the shifts in drug policy, legislation, police tactics and the judiciary's role in the prisonisation of specific social places. This article intends to bridge a theoretical gap in the study of spatial concentration of incarceration in Brazil, underscoring the relevance of understanding the complex relationship between prisons and marginalised communities within Brazilian cities. 相似文献
874.
Rayana A. Costa M.Sc. Nayara A. dos Santos M.Sc. Thayná S. M. Corrêa B.Sc. Nathália L. P. Wyatt B.Sc. Carlos A. Chamoun Ph.D. Maria T. W. D. Carneiro Ph.D. Wanderson Romão Ph.D. 《Journal of forensic sciences》2020,65(6):2188-2193
The concentrations of lead (Pb), barium (Ba), and antimony (Sb), characteristic of GSR, were determined in soil sediments and immature (larvae) of cadaveric flies of the family Calliphoridae, by inductively coupled plasma mass spectrometry (ICP-MS). This research refers to a case study from two real crime scenes in which the corpses were in an advanced state of decomposition. In case 1, the victim had holes similar to gunshot wounds, and in case 2, there was no evidence of perforations in the corpse. Soil sediment collection was performed at three different points of the terrain, at a minimum distance of 10 m from the corpse, for cases 1 and 2. In relation to the collection of immatures, larvae were collected in regions of the mouth, nose, and orifices similar to the entry of firearms projectile into the body, for case 1, and collection of larvae and pupae, located on the body and underneath it, for case 2. It was possible to detect and quantify the three elements of interest (Pb, Ba, and Sb) by ICP-MS in both sediment and cadaveric larvae. Concentrations of 4.44, 8.74, and 0.08 μg/g were obtained for Pb, Ba, and Sb, respectively, in the soil for case 1. For the case 2, the concentrations in Pb, Ba, and Sb were from 16.34 to 26.02 μg/g; from 32.64 to 57.97 μg/g and from 0.042 to 0.30 μg/g, respectively. In the larvae, Pb, Ba, and Sb were quantified in cases 1 and 2 with a concentration of 6.28 and 1.78 μg/g for Pb, 1.49 and 2.94 μg/g for Ba, 0.50 μg/g and <LD for Sb, respectively. These new results present the detection of characteristic elements of GSR in cadaveric larvae in humans in a real crime scene, besides highlighting the importance of the study of immature flies, using the ICP-MS technique in forensic analysis. 相似文献
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Andrew M. Sacha BS Isaac C. Willis BS Victoria L. McGuffin PhD Ruth Waddell Smith PhD 《Journal of forensic sciences》2023,68(5):1527-1541
Definitive identification of fentanyl analogs based on mass spectral comparison is challenging given the high degree of structural and, hence, spectral similarity. To address this, a statistical method was previously developed in which two electron-ionization (EI) mass spectra are compared using the unequal variance t-test. Normalized intensities of corresponding ions are compared, testing the null hypothesis (H0) that the difference in intensity is equal to zero. If H0 is accepted at all m/z values, the two spectra are statistically equivalent at the specified confidence level. If H0 is not accepted at any m/z value, then there is a significant difference in intensity at that m/z value between the two spectra. In this work, the statistical comparison method is applied to distinguish EI spectra of valeryl fentanyl, isovaleryl fentanyl, and pivaloyl fentanyl. Spectra of the three analogs were collected over a 9-month period and at different concentrations. At the 99.9% confidence level, the spectra of corresponding isomers were statistically associated. Spectra of different isomers were statistically distinct, and ions responsible for discrimination were identified in each comparison. To account for inherent instrument variations, discriminating ions for each pairwise comparison were ranked based on the magnitude of the calculated t-statistic (tcalc) value. For a given comparison, ions with higher tcalc values are those with the greatest difference in intensity between the two spectra and, therefore, are considered more reliable for discrimination. Using these methods, objective discrimination among the spectra was achieved and ions considered most reliable for discrimination of these isomers were identified. 相似文献
879.
Arun S. Moorthy PhD Edward P. Erisman MS Anthony J. Kearsley PhD Yuxue Liang PhD Edward Sisco PhD William E. Wallace PhD 《Journal of forensic sciences》2023,68(5):1494-1503
Fentanyl analogs are a class of designer drugs that are particularly challenging to unambiguously identify due to the mass spectral and retention time similarities of unique compounds. In this paper, we use agglomerative hierarchical clustering to explore the measurement diversity of fentanyl analogs and better understand the challenge of unambiguous identifications using analytical techniques traditionally available to drug chemists. We consider four measurements in particular: gas chromatography retention indices, electron ionization mass spectra, electrospray ionization tandem mass spectra, and direct analysis in real time mass spectra. Our analysis demonstrates how simultaneously considering data from multiple measurement techniques increases the observable measurement diversity of fentanyl analogs, which can reduce identification ambiguity. This paper further supports the use of multiple analytical techniques to identify fentanyl analogs (among other substances), as is recommended by the Scientific Working Group for the Analysis of Seized Drugs (SWGDRUG). 相似文献
880.
Sarah A. Shuda;Joshua F. Folger;Erin Spargo;Barry K. Logan; 《Journal of forensic sciences》2024,69(5):1718-1729
A quantitative gas chromatography mass spectrometry (GC/MS) method was developed for delta-9-tetrahydrocannabinol (delta-9-THC), delta-8-tetrahydrocannabinol (delta-8-THC), tetrahydrocannabinolic acid (THCA), and cannabidiol (CBD) in matrices including plant material, liquids and oils, waxes, edibles, and bath and body products. Samples were prepared by homogenization, extraction of the cannabinoids into solvent, liquid/liquid extraction, and derivatization. The GC/MS method was validated from 0.15% to 5.00% (weight basis) to encompass the 0.3% legal distinction between hemp and marijuana. Validation was performed assessing imprecision/bias, calibration model, recovery, interferences, limit of detection, matrix matching, carryover, accuracy, and an assessment of CBD conversion to delta-9-THC. The calibration curves were quadratic weighted 1/x with r2 > 0.990. The method had a detection limit of 0.075% in plant material for each analyte. Analyte recovery was greater than 70% in plant material. Carryover was not observed up to concentrations equivalent to 100% analyte, and no forensically significant conversion of CBD to delta-9-THC was observed. One cannabinoid isomer, 9(R)-delta-7-tetrahydrocannabinol (9(R)-delta-7-THC), was determined to interfere with the quantitation of delta-9-THC, but could be differentiated based on mass spectrum. The method was determined to be suitable for quantitation of delta-9-THC, delta-8-THC, delta-9-THCA, and CBD and was able to differentiate hemp samples from marijuana samples. 相似文献