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41.
本文在无氧条件下利用ESR分别观察了肝脏和晶状体的微粒体及线粒体酶在NADPH存在下还原三硝基甲苯(TNT)的过程,检测到参数为g=2.0048±0.0005,A对位N=1.215mT,A对位N=0.800±0.010mT,AH=0.122±0.0206mT的自由基信号,并通过电子计算机对ESR谱的模拟证明该自由基信号为TNT硝基阴离子自由基,根据其超精细分裂常数认为,其不配对电子的电子云密度主要分布在对位硝基上。 相似文献
42.
The 2,2',4,4',6,6'hexanitrostilbene, HNS, nucleant, used in the crystallisation of 2,4,6,trinitrotoluene, TNT, was precipitated from molten TNT and examined by differential scanning calorimetry, DSC, at several stages during purification by vacuum sublimation. During purification a broad endotherm, associated with nucleant decomposition, which could be resolved into two endotherms, depending on the sublimation temperature, was observed. Pure nucleant prepared at 70C showed a similar behaviour during thermal annealing for extended periods of time at >85C. Thus TNT, retained in the recrystallised HNS nucleant, may be migrating during the purification process or may occupy a range of lattice sites, which exhibit different activation energies for migration to the surface of the solid during thermal decomposition of the nucleant. Loss of TNT from the nucleant, during purification, could produce some free HNS. The activation energy for nucleant decomposition, which may be a two-stage processes with the initial mobility of the TNT being the limiting reaction, was estimated to be 210 kJ mol–. The lattice sites available for the TNT in the host HNS nucleant require elucidation and are the subject of further studies to be published at a later date. 相似文献
43.
Krämer PM Kremmer E Weber CM Ciumasu IM Forster S Kettrup AA 《Analytical and bioanalytical chemistry》2005,382(8):1919-1933
Five new rat monoclonal antibodies (mAbs) for 2,4,6-trinitrotoluene (TNT) and other nitroaromatic compounds, including, especially, the metabolite 2-amino-4,6-dinitrotoluene (2-ADNT), are described. Five heterogeneous, competitive enzyme-linked immunosorbent assays (ELISAs) were developed. Assay 1 uses mAb DNT4 3F6 as recognition element and gives a standard curve for TNT in 40 mmol L–1 phosphate buffered saline (PBS) with a test midpoint (IC50) of 0.26±0.08 g L–1 (n=20). Assay 2 (mAb DNT4 4G4) has an IC50 of 0.35±0.07 g L–1 (n=18), assay 3 (mAb DNT4 1A3) has an IC50 of 0.73±0.14 g L–1 (n=15), and assay 4 (mAb DNT4 1A7) has an IC50 of 2.32±0.70 g L–1 (n=15). Assay 5 (mAb DNT2 4B4) is very selective for 2-ADNT and has an IC50 of 8.5±1.7 g L–1 (n=15) in PBS. These antibodies for nitroaromatic compounds differ not only in their sensitivity but also in their selectivity. Major cross-reactants are 1,3,5-trinitrobenzene, 2-ADNT, 4-amino-2,6-dinitrotoluene (4-ADNT), 2,4-dinitroaniline, 3,5-dinitroaniline, and 2,6-dinitroaniline. Although assay 5 is not highly sensitive, the mAb DNT2 4B4 in this assay is highly selective for 2-ADNT. Of all the compounds tested, only 2,4-dinitroaniline and 3,5-dinitroaniline had relevant cross reactivities, 18% and about 26%, respectively. Two ELISAs, using mAbs DNT4 3F6 and DNT2 4B4, were used to analyze different concentrations of TNT and 2-ADNT, respectively, in three different surface water matrices (river and lake water). Both assays were affected by the matrix, but usually performed well (recovery within the range 70–120%). In addition, these ELISAs were used to analyze mixtures of TNT, 2-ADNT, and 4-ADNT, at three different concentrations, in the same water matrices. A different recognition pattern was clearly visible with both assays and depended on the cross reactivities of the corresponding mAb.Dedicated to the memory of Wilhelm Fresenius 相似文献
44.
The goal of this work was to propose a possible mechanism for the butyrylcholinesterase activation by 2,4,6-trinitrotoluene (TNT), 3,3-dimethylbutyl-N-n-butylcarbamate (1), and 2-trimethylsilyl-ethyl-N-n-butylcarbamate (2). Kinetically, TNT, and compounds 1 and 2 were characterized as the nonessential activators of butyrylcholinesterase. TNT, and compounds 1 and 2 were hydrophobic compounds and were proposed to bind to the hydrophobic activator binding site, which was located outside the active site gorge of the enzyme. The conformational change from a normal active site gorge to a more accessible active site gorge of the enzyme was proposed after binding of TNT, and compounds 1 and 2 to the activator binding site of the enzyme. Therefore, TNT, and compounds 1 and 2 may act as the excess of butyrylcholine in the substrate activator for the butyrylcholinesterase catalyzed reactions. 相似文献
45.
Tyler L. Duniho Brynna J. Laughlin Ashley A. Buelt William F. Baker Catherine A. Conrad Rhett C. Smith 《Journal of polymer science. Part A, Polymer chemistry》2014,52(10):1487-1492
A series of eight poly(p‐phenylene vinylene) (PPV) and poly(p‐phenylene ethynylene) (PPE) ( P1–P8 ) derivatives were tested for their ability to detect the nitroaromatic explosive 2,4,6‐trinitrotoluene (TNT) and its model compound 2,6‐dinitrotoluene (DNT). The polymers P1–P8 represent five structural classes that have not been examined for nitroaromatic sensing. These new motifs include PPE derivatives with a main‐chain m‐terphenyl unit ( P1 ) or oxacyclophane canopy‐like structure ( P2 ) and PPV derivatives with 2,6‐mesitylenephenylene repeats ( P3 and P4 ), 9,9‐dialkyl‐1,4‐fluorenylene repeats ( P5 and P6 ), or m‐phenylene units that periodically disrupt π‐conjugation along the backbone of the polymer ( P7 and P8 ). The time‐dependent photoluminescent response of films to TNT and DNT and the solution‐phase Stern‐Volmer quenching constants for both TNT and DNT were determined. The results are rationalized in terms of side‐chain sterics and π‐system electronics and are discussed relative to known conjugated polymers. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1487–1492 相似文献
46.
Mladen Simonoviíc Svetlana Milosević-Zlatanović Nenad Milosavić Miroslav M. Vrvić Branislav Simonović 《Chemical Papers》2009,63(4):391-398
Diverse recombinant immunoreagents specific for TNT-derivatives were tested in different assay forms in order to analyze their
specificity and sensitivity. Performance of immunoassays was based on TNP-protein conjugates immobilization on a solid surface.
In this work, the detection limit for TNT-analog TNP-Tris was 250 fmol or 87 pg mL−1 (87 ppt), which represents the most sensitive assay published until now, regarding the detection of recombinant antibodies. 相似文献
47.
We report fluorescence quenching of the conjugated polymer poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene (MDMO-PPV) in the presence of nitrated explosives, such as, 2,4,6-trinitrotoluene (TNT). It is found that the conjugated polymer changes color from orange to brownish black when sprayed on traces of TNT within a few seconds. Fluorescence quenching of the conjugated polymer in the presence of TNT is also studied by absorption and emission spectroscopy. The conjugated polymer is highly selective for sensing TNT in daylight and ambient conditions. 相似文献
48.
《Analytical letters》2012,45(7):1463-1474
Abstract Current methods for the analysis of explosives in soils utilize time consuming sample preparation workups and extractions. The method detection limits for EPA Method 8330 for most analytes is substantially higher than the typical explosive concentrations encountered in soils near unexploded ordnance items, landmines, or other hidden explosive devices. It is desirable to develop new analytical techniques to analyze soil with low concentrations of explosives to support the development of explosive sensors. This report describes efforts to adapt headspace solid phase extraction and gas chromatography/mass spectrometry to provide a convenient and sensitive analysis method for explosives in soil. 相似文献
49.
50.
Aoife M. O'Mahony Gabriela Valdés‐Ramírez Joshua Ray Windmiller Izabela A. Samek Joseph Wang 《Electroanalysis》2012,24(9):1811-1816
This article describes a rapid and reliable electrochemical/enzymatic method of verifying the presence of nitroaromatic explosives. The new technique leverages both conventional voltammetric analysis and biocatalytic conversion of TNT. The simultaneous use of independent measurement schemes, based on two distinct processes, dramatically increases the information content and offers substantially improved reliability while minimizing the occurrence of false alarms. This has been accomplished by coupling direct voltammetric analysis with the biocatalytic conversion of the TNT substrate via nitroreductase (NR), which reduces a nitro group of TNT using NADH as an electron donor. This chemical reduction (30 s timescale) can then be observed using square‐wave voltammetry by examination of the reductive and oxidative features. This novel protocol was found to be selective for TNT, not only when compared to DNT and NT, but also to other explosive species such as RDX and PETN. This unique dual‐mode detection strategy for measuring TNT at a single device holds considerable promise for improving the probability of explosive detection and hence for diverse security screening applications. 相似文献