共查询到17条相似文献,搜索用时 93 毫秒
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土壤和沉积物中凝聚态有机质的表征 总被引:1,自引:0,他引:1
在375℃条件下用三氟醋酸(TFA)、通氧燃烧的方法,从珠江三角洲被污染的3个土壤和6个沉积物样品中提取非水解有机碳(NHC)和碳黑(BC),并进行了元素分析、傅里叶变换红外光谱(FTIR)、固态13C核磁共振(13CNMR)、放射性碳加速质谱等一系列定性、定量的研究。结果表明:用三氟醋酸(TFA)可以成功地提取凝聚态的非水解碳,消除了碳水化合物等可水解有机质对凝聚态有机质研究的干扰。样品中非水解碳和碳黑碳分别占总有机碳含量的25.6%~70.5%和4.14%~17.3%,其平均值分别为44.2%和11.2%。非水解碳和碳黑两者的O/C和H/C比值都比较低;13C核磁共振显示NHC中主要含有脂肪碳和芳香碳峰,其中含氧官能团几乎可以忽略。研究表明,非水解碳主要由不同成熟度的沥青或干酪根、古老的陆源有机质、碳黑、煤、木质素等组成。实验结果表明:用水解的方法可以从土壤和沉积物中分离出凝聚态的碳。 相似文献
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裂解毛细管柱气相色谱-傅里叶变换红外光谱的剖析应用 总被引:1,自引:0,他引:1
采用裂解气相色谱-傅里叶变换红外光谱(PyGC/FTIR)技术,使用大口径毛细管柱,分析了一未知进口涂料,对其主要裂解碎片峰进行了定性,进而从特征碎片的产生推出该涂料的成分。并同常规红外光谱差减法进行了比较,结果表明PyGC/FTIR具有简便、快速、全面和无需标样等优点,有广泛的应用价值。 相似文献
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采用裂解气相色谱-傅里叶变换红外光谱(PyGC/FTIR)技术,使用大口径毛细管柱,分析了一未知进口涂料,对其主要裂解碎片峰进行了定性,进而从特征碎片的产生推出该涂料的成分。并同常规红外光谱差减法进行了比较,结果表明PyGC/FTIR具有简便、快速、全面和无需标样等优点,有广泛的应用价值。 相似文献
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采用国产色谱仪与进口红外光谱仪及接口组成的气相色谱-傅里叶变换红外光谱(GC/FTIR)分析仪,使用大口径毛细管柱,分析了乙苯与苯乙烯固相催化反应液的复杂芳香烃异构体组成,讨论了GC/FTIR分析中随机噪声和基线漂移的去除方法。采用等高线图(CTD)分析技术得到了混合液中各组分的纯气相红外光谱图,最后鉴定了14个气相色谱峰中的9个,占整个色谱峰面积99%以上。 相似文献
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Characterization and Three-dimensional Structural Modeling of Humic Acid via Molecular Mechanics and Molecular Dynamic Simulation 总被引:2,自引:0,他引:2
The humic acid(HA) sample obtained from the alluvial soil was characterized by elemental composition, pyrolysis gas chromatography-mass spectrometry(Py-GC-MS) and solid-state 13C nuclear magnetic resonance (13C NMR) spectroscopy. There is high fat content and a few nitrogen-containing functional groups in HA. Py-GC-MS demonstrates the characterization and structural identification of HA. One long list of identified pyrolysis products was proposed for the construction of conceptual model of HA. Solid-state 13C NMR data indicate there are higher values of alkyl-C, O-alkyl-C and aryl-C in HA. The elemental composition, structural carbon distribution and L3C NMR spectroscopy of simulated HA are consistent with those of experimental HA. HyperChem was used to simulate the three-dimensional molecular structure of the monomer, which was optimized by the molecular mechanics of the optimized potential for liquid simulations(OPLS) force field and molecular dynamics simulation to get the stable and balanced conformation. The deprotonation process study depicts that the degree of ionization of HA gets deeper, while the electronegativity of HA and the energy of van der Waals(vdW) increase. Moreover, the 3D structure of humic acid with -4 charges is the most stable. The deprotonation process is an endothermic process. 相似文献
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Qiheng Tang 《International Journal of Polymer Analysis and Characterization》2017,22(7):569-574
One kind of unknown structure sequence and composition ratio of thermoplastic polyurethane elastomers were characterized by nuclear magnetic resonance spectroscopy, Fourier transformed infrared spectroscopy, and gel permeation chromatography (GPC). The results showed that the polyurethane (PU) was obtained from poly(tetramethylene glycol) (PTMG) as soft segment, 1,4-butanediol (BDO) as chain extender, and 4,4′-methylenediphenyl diisocyanate (MDI) as hard segment. Furthermore, the composition ratio of MDI:PTMG:BDO was 2.07:1.22:1.00. At last, the molecular weight of PU was determined by GPC, and the number average molecular weight (Mn) and weight average molecular weight (Mw) are 63,300 and 133,800?g?mol?1, respectively. 相似文献
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