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排序方式: 共有383条查询结果,搜索用时 15 毫秒
41.
Abstract: Thin layer chromatography (TLC) is a technique that is commonly employed in the forensic drug analysis of pharmaceutical preparations. Detection is typically accomplished using various visualization spray reagents. Conventional gas chromatography–mass spectrometry (GC‐MS) analysis is typically performed to confirm the TLC results. Depending on the drugs tested and the instrument conditions required, this confirmation can take up to an hour to complete. Direct analysis in real time (DART?) is an ionization source, coupled to an accurate‐mass time‐of‐flight mass spectrometer that has the capability to ionize materials under ambient conditions. To streamline analysis, the combination of TLC with DART? detection is proposed to screen and subsequently identify drug compounds, all from the same TLC plate. DART? confirmations of TLC analyses take <10 min to complete and compare favorably to GC‐MS in sensitivity and selectivity. This study validates the use of TLC‐DART in the forensic identification of the components of several pharmaceutical preparations. 相似文献
42.
The analysis of gamma-hydroxybutyric acid (GHB) is problematic because it is hygroscopic, it lacks a good UV chromophore, and it undergoes heat-induced cyclization. This paper presents a new method utilizing ion-exchange chromatography (IC) with conductivity detection. The simple sample preparation, rapid analysis time, and inorganic anion detection capabilities are all advantages over the current methods. The detection of inorganic salts (formed during GHB synthesis) gives insight into the synthetic route utilized and can aid in drug seizure comparison. The developed method has a detection limit for GHB anions of 0.57 mg/L and chloride of 0.22 mg/L. A comparison of this technique with a current gas chromatography-mass spectrometry technique is presented, and a t-test found that the two methods' results are not statistically different at the 99.9% confidence level demonstrating the merits of this fast, simple, and informative IC method as a routine screening tool. 相似文献
43.
甲基苯丙胺和乙醇在染毒大鼠体内联用的实验研究 总被引:1,自引:1,他引:0
目的研究甲基苯丙胺(MA)和乙醇联合应用在急性、亚急性染毒大鼠体内的情况。方法以MA1.0 mg/kg剂量对慢性自由饮酒大鼠多次腹腔注射,分别建立急性、亚急性染毒大鼠模型;处死后即时检测血中乙醇浓度、体液和组织样品中MA的浓度。结果多次注入MA药后,亚急性中毒大鼠体内的MA浓度高于急性中毒大鼠;急性和亚急性联合中毒大鼠体内MA浓度均高于急性和亚急性单一药物组。结论无论是否联用乙醇,14d内增加注射次数会在大鼠体内产生不同程度的MA残留;与乙醇联用可加速MA在大鼠体内的吸收,其药物浓度的升高程度随生物样品不同存在差异。 相似文献
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46.
Alternative fuels are becoming more prominent on the market today and, soon, fire debris analysts will start seeing them in liquid samples or in fire debris samples. Biodiesel fuel is one of the most common alternative fuels and is now readily available in many parts of the United States and around the world. This article introduces biodiesel to fire debris analysts. Biodiesel fuel is manufactured from vegetable oils and/or animal oils/fats. It is composed of fatty acid methyl esters (FAMEs) and is sold pure or as a blend with diesel fuel. When present in fire debris samples, it is recommended to extract the debris using passive headspace concentration on activated charcoal, possibly followed by a solvent extraction. The gas chromatographic analysis of the extract is first carried out with the same program as for regular ignitable liquid residues, and second with a program adapted to the analysis of FAMEs. 相似文献
47.
Traditional forensic soil comparisons are performed via physical and/or chemical examinations of color, texture, and mineral content, leaving any organic- or water-soluble fractions unexamined. This study uses high-performance liquid chromatography (HPLC) and ion chromatography (IC) to assess the qualitative and quantitative variation in these fractions of soil. Soil samples (n=120) were collected over the course of 3 weeks from urban, suburban, and rural locations in and around Lansing, MI. Additional samples from six of these locations (two urban, two suburban, and two rural) were collected once a week for 10 weeks for temporal analysis. Nine additional samples, equally spaced over a 1 m(2) grid, from these same six locations were collected for spatial analyses. Qualitative and quantitative analysis of the resultant chromatograms separated the 120 samples into 10 groups by HPLC and 23 groups by IC. This study shows that using HPLC and IC to analyze the organic- and water-soluble fractions of soil can successfully discriminate samples. Quantitative analysis of the results eliminates some false inclusions by providing further differentiation of samples. The results of this study indicate that adding HPLC and IC analyses to traditional forensic soil analysis schemes can improve overall sample differentiation. The methods used in this study were also able to detect both qualitative and quantitative variations in soil over a relatively small geographic area. This demonstration of soil heterogeneity underscores the importance of the collection of a representative known sample population when assessing a forensic soil comparison. Significant temporal variation was also demonstrated over the course of 10 weeks of sampling; however, samples were found to be consistent over shorter periods of time. Baseline levels of inorganic anions were determined via IC; these levels may be useful in assessing the significance of anions detected in soil from cases involving low explosives. 相似文献
48.
Allison M. Curran Ph.D. ; Paola A. Prada B.S. ; Kenneth G. Furton Ph.D. 《Journal of forensic sciences》2010,55(1):50-57
Abstract: Human scent evidence is utilized as an investigative tool through canine scent discriminations based on the premise that human scent is an individualizing characteristic. This study describes the development of what is effectively a human scent barcode consisting of the relative ratios of an individual's "primary odor" compounds utilized to determine a reproducible and individualizing profile which can be stored in a searchable database for a proof of concept of human scent as a biometric measure. Triplicate hand odor samples were evaluated from 10 subjects utilizing solid phase micro-extraction gas chromatography/mass spectrometry (SPME-GC/MS) and compared via Spearman Rank Correlations. Narrowing the compounds considered for each subject to only those common in all three samples, or a subject's "primary odor constituents," produced a greater degree of both individualization and discrimination; at both correlation thresholds of 0.9 and 0.8, the individuals were correctly discriminated and identified in 99.54% of the cases. 相似文献
49.
Anders Buchard M.Sc. Kristian Linnet M.D. D.M.Sc. Sys Stybe Johansen Ph.D. Julie Munkholm M.D. Michael Fregerslev M.D. Niels Morling M.D. D.M.Sc. 《Journal of forensic sciences》2010,55(2):457-463
Abstract: We investigated toxicological and pharmacogenetic factors that could influence methadone toxicity using postmortem samples. R‐ and S‐methadone were measured in femoral blood from 90 postmortem cases, mainly drug users. The R‐enantiomer concentrations significantly exceeded that of the S‐enantiomers (Wilcoxon’s test, p < 0.001). The samples were divided into four groups according to other drugs detected (methadone only, methadone and strong analgesics, methadone and benzodiazepines, or methadone and other drugs). There was no significant difference in any of the R‐methadone/total methadone ratios among the four groups. The median R/S ratio was 1.38, which tends to be higher than that reported for the plasma of living subjects. In addition, we investigated whether small nucleotide polymorphisms in the MDR1 gene that encode the drug transporter P‐glycoprotein were associated with the concentrations of R‐ and S‐methadone and its metabolite 2‐ethylidene‐1,5‐dimethyl‐3,3‐diphenylpyrrolidine. No significant association was detected. 相似文献
50.
Greg W. Cook Ph.D. Peter T. LaPuma Ph.D. Gary L. Hook Ph.D. Brian A. Eckenrode Ph.D. 《Journal of forensic sciences》2010,55(6):1582-1591
Abstract: Ion mobility spectrometry (IMS) is a valued field detection technology because of its speed and high sensitivity, but IMS cannot easily resolve analytes of interest within mixtures. Coupling gas chromatography (GC) to IMS adds a separation capability to resolve complex matrices. A GC‐IONSCAN® operated in IMS and GC/IMS modes was evaluated with combinations of five explosives and four interferents. In 100 explosive/interferent combinations, IMS yielded 21 false positives while GC/IMS substantially reduced the occurrence of false positives to one. In addition, the results indicate that through redesign or modification of the preconcentrator there would be significant advantages to using GC/IMS, such as enhancement of the linear dynamic range (LDR) in some situations. By balancing sensitivity with LDR, GC/IMS could prove to be a very advantageous tool when addressing real world complex mixture situations. 相似文献