A New Model for the Genesis of Natural Gases--Multi-source Overlap, Multi-stage Continuity, Type Controlled by Main Source and Nomenclature by Main Stage (Ⅰ)--Multi-source Overlap and Type Controlled by Main Source

Based on the geochemical studies of natural gases in the past ten years in China, the authors have proposed a new model for their genesis--multi-source overlap, multi-stage continuity, main source-controlling type and nomenclature by the main stage.Multi-source refers to a diversity of material sources involved in the formation of natural gases, including abiogenic and biogenic material sources. In regard to biogenic sources, either oil-generating or coal-generating organic matter would produce gaseous hydrocarbon reservoirs of commercial importance. Generally, natural gases originating from these sources can overlap to form gas reservoirs. Under specific circumstances mantle-source abiogenic gases could overlap biogenic gases to form gas reservoirs. In nature, natural gases predominated by gaseous hydrocarbons may be formed from a single end-member source. However, multi-source overlap is more typical of the genesis of natural gases.     

沉积有机质的加氢热解及其地球化学信息研究

用加氢热解(hydropyrolysis)释放高演化源岩干酪根和沥青分子网络中共价键结合的生物标志物,在恢复原始有机地球化学信息方面具有重要的意义,可应用于源岩有机质生源确定、成熟度确定、古沉积环境判识以及油/源对比等.实验表明,样品沥青“A“与加氢热解产物中生物标志物的组成存在一定的差异,加氢热解产物中含有丰富的地球化学信息.加氢热解具有产物收率高、结构重排少、生物特征保持完整等特点,能够合理地释放出沉积有机质分子骨架中具有原生性的组分,保持完整的原始生物标志物结构和立体化学特征.加氢热解技术为油气地球化学研究开辟了新途径.     

Analysis of Organic Compounds in Antarctic Snow and Their Origin

Abstract

Organic compounds extractable with n-hexane were identified and quantitatively determined in pack, surface and deep snow samples taken at different depths and collected at several altitudes above sea level from Antarctica during the 1993/94 Italian expedition. The comparison between the composition of organic compounds in snow and the ones in pack and sea-water samples pointed out that the three matrices substantially contain the same biogenic and anthropogenic organic compounds. The contribution of marine aerosol to organic content in the snow is confirmed by the enrichment ratios calculated for the more representative classes of identified compounds (n-alkanes, phthalates and low molecular weight alkylbenzenes). The changes in the composition of organic compounds in snow as the altitude increases seem to depend on the dimensional spectrum of the aerosol. Thus, smallest particles, richest in surfactant material, reach the highest altitudes.     

Polyphenols of the herb Hypericum perforatum and the preparation novoimanin

Summary 1. The herbHypericum perforatum L. has been shown by paper chromatography to contain 14 substances with a polyphenolic nature, five from the flavonoid group (identified as hyperoside, isoquercitrin, quercitrin, rutin, and quercetin), four from the dianthrone group, and five from the group of low-polarity phenolic glycosides of undetermined structure.2. The composition of the polyphenols of novoimanin has been studied. This preparation has been found to contain five substances from the group of low-polarity phenolic glycosides, which are present in considerable amounts, and nine substances from the group of flavonoids and dianthrones which are present in small amounts.3. It has been established that theH. perforatum raw material after the extraction of the novoimanin still contains a considerable amount of flavonoid compounds, and the raw material can be used for the preparation of quercetin and hyperoside.4. A spectrophotometric method for the quantitative determination of hyperoside in the herbage, stems, and flowers ofH. perforatum and in the wastes from the production of novoimanin has been developed.Kiev Institute for the Further Training of Doctors. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 363–367, May–June, 1971.     

Recent electroanalytical applications of boron-doped diamond electrodes

This review overviews recent reports on the electroanalytical applications of boron-doped diamond (BDD) electrodes. Because BDD electrodes have excellent features for electroanalysis, such as wide potential window, low background current, electrochemical stability, and fouling resistance, they can be useful for sensitive and stable detection of various substances, including drugs, bio-related substances, metal ions, and organic pollutants. Many articles have reported high-sensitivity detection of real samples, demonstrating that this electrode material is practically applicable. Surface modification of the BDD electrodes using metal nanoparticles, nanocarbons, and polymers can increase the sensitivity of the electrochemical detection. Furthermore, research on the electroanalytical device equipped with BDD electrodes will be expanded by combining peripheral technologies related to the device fabrication.     

Attenuated Total Reflection-Fourier transform infrared microspectroscopic mapping for the characterisation of paint cross-sections

Paint cross-sections have been analysed using the attenuated total reflection technique combined with FTIR mapping microspectroscopy in order to characterise the nature of the compounds present and map their localisation in the stratigraphy. The study reveals the possibilities offered by micro-ATR devices for obtaining informations about the organic substances employed in painting techniques and in particular their distribution in the different layers, showing a real improvement over traditional analytical investigations in use for the detection of organic substances. Limitations, such as the contamination of the embedding resin and the typical spectral resolution (20 μm) are presented and alternative methods were proposed to obtain better results. In particular, the use of an infrared transparent salt (KBr) as embedding material for the cross-sections is evaluated and seems to be very promising. Furthermore, ATR mapping represent a useful non-destructive analytical technique complementary to others molecular and elemental analyses to be performed afterwards such as SEM-EDX.     

Biogenic synthesis of gold and silver nanoparticles used in environmental applications: A review

Due to their physical, chemical, optical, and mechanical properties, metallic nanoparticles (MNPs) are increasingly being used, with an emphasis on silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs). In recent years, green synthesis has gained prominence for exploring the use of naturally available biological sources for the obtention of metallic nanoparticles. Among these, algae and plants stand out due to the presence of polysaccharides, proteins, polyphenols, and vitamins (among others) in their composition, which can act in the reduction and stabilisation of MNPs, and these biogenic materials have been characterised mainly by spectrometric and microscopic techniques. In addition, due to the numerous advantages of nanoparticles (NPs) synthetize from biogenic source, such as their simplicity and cost benefits, they have been used in the development of sensors applied in the determination of contaminants present in environmental samples and in the catalytic reduction of organic and inorganic contaminants. Therefore, this review describes the synthesis, mechanisms, characterization, and environmental analytical applications of NPs obtained by biogenic synthesis as well as the perspectives and challenges of these NPs.     

Application of CE in hydrodynamically closed systems for analysis of bioactive compounds in food

CE is a family of electrokinetic separation techniques that separate compounds based upon differences in electrophoretic mobilities, phase partitioning, pI, molecular size, or a combination of one or several of these properties. CE has been used in several modes to analyze and characterize a wide variety of analytes from simple inorganic ions, small organic molecules, peptides, proteins, nucleic acids to virus, microbes and particles. Food consists of a complex mixture of a variety of components, many of which are biologically active. Components classified as "nutrients" are essential for growth, maintenance, and repair of the body. Other food constituents, typically occurring in small quantities, are classified as "biologically active substances" and they have beneficial or harmful effects on human health. There are two types of biologically active substances in food - naturally occurring and food additives. The bioactive compounds of food that will be mentioned in this review are inorganic and organic acids, amino acids, vitamins, phenolic compounds, biogenic amines, antinutrients, toxins, etc. This review is focused on the application of CE with hydrodynamically closed system (suppression of EOF) for the analysis of the above-mentioned compounds. CE can be an alternative method to HPLC or other methods for analysis of bioactive compounds in food. The main advantages of CE are low running cost (at least ten times than HPLC) and consideration to environment (hundreds of microliters of diluted water based electrolyte per analysis).     

HUMIC MACROMOLECULES IN NATURAL WATERS

Abstract

Humic substances are the major organic constituents of soils and sediments. They also occur in small concentrations in natural surface waters and groundwaters. They form through the breakdown of plant and animal tissues by chemical and biological processes that tend to produce complex chemical structures that are more stable than the original material from which they were derived. One of the more important characteristics of humic substances is their ability to form water-soluble and water-insoluble complexes with metal ions and hydrous oxides and to interact with clay minerals and various organic compounds such as alkanes, fatty acids, and toxic organic substances such as pesticides.     

Relaxed eddy accumulation,a new technique for measuring emission and deposition fluxes of volatile organic compounds by capillary gas chromatography and mass spectrometry

The possibility afforded by a new relaxed eddy accumulation system in the determination of emission and deposition fluxes of volatile organic compounds (VOCs) by chromatographic techniques will be presented. The system, especially designed to limit sampling artifacts, uses adsorption traps filled with solid sorbents as reservoirs for VOC collection. Enriched compounds were analyzed by capillary GC and positive identification and quantification of eluted compounds was Achieved by mass-spectrometric detection. The method has been used to quantify the emission and deposition of both biogenic and anthropogenic VOCs over a Mediterranean forest ecosystem located in Central Italy. For the first time, both daily and seasonal trends of anthropogenic and biogenic VOCs will be reported. The consistency of monoterpene fluxes with predictions based on the knowledge of VOC emission from the dominant vegetation species will be tested. Data have been used to develop a novel algorithm to predict the seasonality of biogenic emission from the forest ecosystem.     

Trace metal recovery and concentration using ferrites

Ferrites have been used to separate a wide range of substances such as dissolved metal species, particulate matter, and organic and biological materials; they have been used almost exclusively for metal waste treatment applications. However, ferrites can be used to remove and concentrate selected trace metals in a wide variety of feed solutions requiring analysis. A brief overview of ferrite properties and recent applications for trace metal recovery and concentration will be presented.     

Selection of a piezoelectric sensor array for detecting volatile organic substances in water

Sensitive coatings for piezoelectric sensors used to assess the presence of anthropogenic volatile organic substances in the equilibrium gas phase over natural water have been selected using an array of measuring elements, and the data have been processed using principal component analysis. Groups of piezoelectric sensors with similar characteristics for substance identification have been determined based on the correlation between piezoelectric sensor responses when vapors of organic substances were detected. The stepby-step optimization of the piezoelectric sensor array has been carried out in order to identify the greatest number of organic compounds (vapors) in the sample. Volatile organic compounds can be identified in their aqueous solutions and natural water using the optimized piezoelectric sensor array.     

The use of FT-IR as a screening technique for organic residue analysis of archaeological samples

A range of archaeological samples have been examined using FT-IR spectroscopy. These include suspected coprolite samples from the Neolithic site of Catalh?yük in Turkey, pottery samples from the Roman site of Silchester, UK and the Bronze Age site of Gatas, Spain and unidentified black residues on pottery sherds from the Roman sites of Springhead and Cambourne, UK. For coprolite samples the aim of FT-IR analysis is identification. Identification of coprolites in the field is based on their distinct orange colour; however, such visual identifications can often be misleading due to their similarity with deposits such as ochre and clay. For pottery the aim is to screen those samples that might contain high levels of organic residues which would be suitable for GC-MS analysis. The experiments have shown coprolites to have distinctive spectra, containing strong peaks from calcite, phosphate and quartz; the presence of phosphorus may be confirmed by SEM-EDX analysis. Pottery containing organic residues of plant and animal origin has also been shown to generally display strong phosphate peaks. FT-IR has distinguished between organic resin and non-organic compositions for the black residues, with differences also being seen between organic samples that have the same physical appearance. Further analysis by GC-MS has confirmed the identification of the coprolites through the presence of coprostanol and bile acids, and shows that the majority of organic pottery residues are either fatty acids or mono- or di-acylglycerols from foodstuffs, or triterpenoid resin compounds exposed to high temperatures. One suspected resin sample was shown to contain no organic residues, and it is seen that resin samples with similar physical appearances have different chemical compositions. FT-IR is proposed as a quick and cheap method of screening archaeological samples before subjecting them to the more expensive and time-consuming method of GC-MS. This will eliminate inorganic samples such as clays and ochre from GC-MS analysis, and will screen those samples which are most likely to have a high concentration of preserved organic residues.     

二嗪类有机光电功能材料的应用进展

在过去的几十年里,有机电子学作为一个新兴领域迅猛发展,为科学技术的进步作出了巨大的贡献.有机材料被应用在各种电子器件中,并取得了卓越的成效.作为使用在电子器件中最基本的组分,有机光电材料更是备受瞩目.二嗪类化合物具有优异的光电性能,是光电材料领域最活跃的研究方向之一.两个N原子相对位置的不同,可以构成三种异构体,分别为哒嗪(1,2-二嗪)、嘧啶(1,3-二嗪)和吡嗪(1,4-二嗪),从而有效地调控材料的电子结构,且可以影响二嗪化合物不同位置的修饰,从而得到了广泛关注.本文对近年来二嗪类化合物在光伏材料、薄膜半导体材料、液晶材料、传感材料和电致发光材料等领域的研究进展进行了较全面的总结和评述,指出目前基于二嗪类化合物的光电材料所面临的困难以及未来的发展方向,最后展望了二嗪类化合物作为杂环类有机光电功能材料的应用前景.     

Determination of biogenic amines in fish tissues by ion-exchange chromatography with conductivity detection

Some biogenic amines, such as putrescine, cadaverine, spermidine and histamine, have been found to be useful as quality indices for the decomposition of fish, so research on the simultaneous analysis of various biogenic amines in food is of interest and importance. The intake of histamine may cause an allergic intoxication known as "scombroid poisoning" while secondary biogenic amines can potentiate the toxicity of histamine and in addition can react with nitrite to form carcinogenic nitrosamines. A new method for the simultaneous determination of underivatized biogenic amines based on ion-exchange chromatography with conductivity detector has been developed. The proposed method offers a number of advantages over previous pulsed amperometric detection and integrated pulsed amperometric detection methods such as simpler extraction procedure and sharp peaks. Separations were performed on a new low hydrophobic weak cation-exchange analytical column. This technique is simple, rapid and useful for routine checks in repetitive analyses.     

乌江流域沉积岩风化过程中稀土元素的富集与释放

以乌江流域石灰岩、白云质灰岩、白云岩、硅质岩、页岩和砂岩等沉积岩的13条风化剖面为对象，运用R型分层聚类分析和质量平衡计算方法，研究了这些岩石风化过程中稀土元素（REE）的富集与释放及其对植物生长和河水REE分布的影响，目的是为河水物质来源研究和为农业生产提供依据。结果表明：（1）乌江流域石灰土中REE的富集程度显著高于各自母岩、黄壤、上陆壳（UCC）、中国土壤（CS）和世界土壤（WS）；（2）沉积岩风化过程中REE的富集特征和机制可能与母岩中REE分布特征以及风化剖面中有机质、铁（氢）氧化物和粘土矿物的吸附有关；（3）沉积岩风化过程中释放的REE可为植物吸收利用；（4）石灰岩等沉积岩风化过程中REE和F。等元素的释放对河水溶解态REE的分布有重要影响。     

The preparation of analytically stable,immobilized stationary phase coatings on colums packing materials

Summary A coating of silicone SE-54 on Chromosorb W has been converted to an analytically stable, immobilized stationary phase layer by cross-linking with an organic peroxide. Up to 10% by weight has been applied in this manner. Excellent high temperature qualities are exhibited, such as low bleeding and good base line stability, during typical analyses.Poly (2,6-dimethyl-p-phenylene oxide) has also been crosslinked as a surface coating on Chromosorb W with an organic peroxide. From 3 to 4% by weight has been immobilized in this way. The resultant packing material, following high temperature conditioning, has been examined for use as an adsorbent of trace substances, similar to the applications to which such adsorbents as Tenax GC have commonly been applied, e.g. trace analysis of air. It appears to exhibit satisfactory properties for this analytical purpose.     

Detection of glucosamine in the acid hydrolysis solution of humic substances

Several humic substances isolated from water and soil have been characterized applying acid hydrolysis to release defined components bound in these high molecular organic compounds. The hydrolysis solution have been analyzed by HPLC after precolumn derivatization with o-phthalaldehyde and 9-fluorenylmethylchloroformate. Under these conditions the nitrogen containing carbohydrate glucosamine could be detected and separated besides seventeen amino acids. The results show that 8.0 to 40.1% of the total nitrogen content of the investigated samples contributes to amino acids and up to 7.9% to the carbohydrate glucosamine. It could be deduced that defined amino acid carbohydrate building blocks were bound in humic substances, because the glucosamine nitrogen content correlates with the calculated amino acid nitrogen. Furthermore the total amino acid nitrogen amount of natural organic matter can be estimated from the results of the determination of glucosamine.     

Detection of glucosamine in the acid hydrolysis solution of humic substances

Several humic substances isolated from water and soil have been characterized applying acid hydrolysis to release defined components bound in these high molecular organic compounds. The hydrolysis solution have been analyzed by HPLC after precolumn derivatization with o-phthalaldehyde and 9-fluorenylmethylchloroformate. Under these conditions the nitrogen containing carbohydrate glucosamine could be detected and separated besides seventeen amino acids. The results show that 8.0 to 40.1% of the total nitrogen content of the investigated samples contributes to amino acids and up to 7.9% to the carbohydrate glucosamine. It could be deduced that defined amino acid carbohydrate building blocks were bound in humic substances, because the glucosamine nitrogen content correlates with the calculated amino acid nitrogen. Furthermore the total amino acid nitrogen amount of natural organic matter can be estimated from the results of the determination of glucosamine.     

Recent Updates on the Barrier Properties of Ethylene Vinyl Alcohol Copolymer (EVOH): A Review

The gas barrier properties of ethylene vinyl alcohol copolymer (EVOH) against oxygen, carbon dioxide and water vapor have been widely investigated in relation to different material characteristics, environmental conditions and new processing technologies. Recently, EVOH is gaining more attention as a barrier material against other gases and organic substances such as aromas, flavors, fuels, chemicals (e.g., BTEX), and as a functional barrier, e.g., to avoid mineral oil migration. This review contains an update on permeability data of EVOH emphasizing its potential as a barrier material for new and versatile applications in food and pharmaceutical packaging, agriculture, construction, automotive, etc.