Complex Chemical System Research Articles

Application and Analysis of V.A.SuLin’s Theory of Oilfield Water

Oilfield water is a complex chemical system whose classification is an important proposition of oilfield water geochemistry. This paper makes some analysis and discussion according to the V.A.SuLin’s theory using the data of some oilfield water samples. The result shows that the theory has some limitations in the classification of oilfield water and should be combined with the actual situation of oilfield development.

Qualitative and quantitative analysis of the major constituents in traditional Chinese medicine Danmu injection using LC-ESI-MS(n) and LC-DAD.

Background:Danmu injection, a traditional Chinese medicine (TCM) preparation made from Nauclea officinalis, has been commonly used for the treatment of cold, fever, swelling of throat in China. However, the chemical constituents in Danmu injection have not been clarified yet.Objective:a HPLC/DAD/ESI-MSn method was developed for qualitative and quantitative analysis of the components in Danmu injection.Materials and Methods:The chromatographic separation was performed on a Welch Material XB-C18 (4.6mm × 250mm, 5μm) using gradient elution with acetonitrile (A) and water containing 0.1% formic acid (B) as mobile phase at a flow rate of 1.0 ml/min.Results:Twenty-five compounds, including phenolic acid and phenol glycoside, iridous glycoside and glycoalkaloid were identified or tentatively deduced on the base of their retention behaviors, UV absorption, MS and MSn data with those elucidated references or literature. In addition, eleven compounds were simultaneously determined by HPLC–DAD, which was validated and successfully applied for determination of major components in Danmu injection.Conclusion:The results suggested that the established qualitative and quantitative method would be a powerful and reliable analytical tool for the characterization of multi-constituent in complex chemical system and quality control of Danmu injection.

Natural pyrrhotite as a catalyst in prebiotic chemical evolution.

The idea of an autotrophic organism as the first living being on Earth leads to the hypothesis of a protometabolic, complex chemical system. In one of the main hypotheses, the first metabolic systems emerged from the interaction between sulfide minerals and/or soluble iron-sulfide complexes and fluids rich in inorganic precursors, which are reduced and derived from crustal or mantle activity. Within this context, the possible catalytic role of pyrrhotite, one of the most abundant sulfide minerals, in biomimetic redox and carbon fixation reactions was studied. Our results showed that pyrrhotite, under simulated hydrothermal conditions, could catalyze the pyruvate synthesis from lactate and that a dynamic system formed by coupling iron metal and iron-sulfur species in an electrochemical cell could promote carbon fixation from thioacetate esters.

Qualitative and Quantitative Analysis of the Constituents in Danmu Preparations by UPLC-PDA-TOF-MS

An ultra performance liquid chromatography coupled with photodiode array detector and time-of-flight tandem mass spectrometry (UPLC-PDA-TOF-MS) method was developed for the quality assessment of Danmu preparations, a commonly used traditional Chinese medicine. Thirty-three compounds from Danmu preparations were simultaneously detected; among them, 14 compounds were unequivocally identified based on their retention behaviors, UV spectrum, MS and MS(n) data by comparing with reference substances, and the others were tentatively characterized by literatures. Twelve of 33 compounds were simultaneously determined by UPLC-PDA, and the validation of the quantitative method, including recoveries, linearity, sensitivity, precision and repeatability was carried out and the results demonstrated to be satisfied the requirements of quantitative analysis. The results suggested that the established method would be a powerful and reliable analytical tool for quality control of Danmu preparations and the characterization of multi-constituent in complex chemical system.

Qualitative and quantitative analysis of cinobufacini injection using rapid separation liquid chromatography coupled with quadrupole‐time‐of‐flight mass spectrometry and HPLC‐photodiode array detection, a feasible strategy for the quality control of Chinese medicine injections

Cinobufacini injection, prepared from the skin of Bufo bufo gargarizans Cantor, has presented its significant effects on the treatment of hepatitis and various cancers in the clinic. However, as an unclear complex chemical system, the optimization of its quality control markers has been a long-term challenge. In present study, a feasible strategy integrated markers screening, determination, and statistical analysis was efficiently proposed, especially for the undefined Chinese medicine injections. First, rapid separation LC-quadrupole-TOF-MS method was applied in the identification of 19 major compounds in the cinobufacini injection for the first time. Further, nine high-level contents active compounds were selected as quality control markers for the quantification analysis. An acceptable and validated determination method was established in 17 batches of cinobufacini injection by HPLC-photodiode array detection method, including linear regression relationship (r(2), 0.9996-1), precisions (RSD, 0.02-1.35%), repeatability (RSD, 0.05-1.97%), stability (RSD, 0.1-3.85%), and recovery (95.88-104.89%). Each analyte was detected at its maximum ultraviolet spectra wavelength. Finally, based on the quantification results, principal component analysis was performed on the quality assessment of cinobufacini injections. This three-step strategy provides a newly feasible solution for the quality control of Chinese medicine injections.

RETRASO, a code for modeling reactive transport in saturated and unsaturated porous media

The code RETRASO (REactive TRAnsport of SOlutes) simulates reactive transport of dissolved and gaseous species in non-isothermal saturated or unsaturated problems. Possible chemical reactions include aqueous complexation (including redox reactions), sorption, precipitation-dissolution of minerals and gas dissolution. Various models for sorption of solutes on solids are available, from experimental relationships (linear KD, Freundlich and Langmuir isotherms) to cation exchange and surface complexation models (constant capacitance, diffuse layer and triple layer models). Precipitation-dissolution and aqueous complexation can be modelled in equilibrium or according to kinetic laws. For the numerical solution of the reactive transport equations it uses the Direct Substitution Approach. The use of the code is demonstrated by three examples. The first example models various sorption processes in a smectite barrier. The second example models a complex chemical system in a two dimensional cross-section. The last example models pyrite weathering in an unsaturated medium.

Interactions of marine-derived γ-pyrone natural products with phospholipid membranes

The sacoglossan mollusc-derived metabolite, tridachiahydropyrone (3), and its proposed biosynthetic precursors (1 and 2) form part of a complex chemical defence system against predators and harmful UV light. Here, we provide supporting biophysical evidence that the metabolites become selectively localised at cell membranes and outline a binding scheme that accommodates the observed data. The possibility that localised lipid domains within the membrane have an effect on the localisation is also addressed.

Topological Biosignatures: Large-Scale Structure of Chemical Networks from Biology and Astrochemistry

The chemical basis of life involves more than simply the presence of biological molecules; biochemical systems embody a complex network of reactions with characteristic topological features. At the same time, chemical complexity is also present in nonbiological contexts, inviting us to clarify the relationship between chemistry and life through comparative studies. This study examines chemical networks from biology (the metabolism of E. coli) and astronomy (gas-phase reactions in dark molecular clouds) to establish common topological features that may be generic for any complex chemical system, as well as clear differences that may be topological signatures of life. The biological and astrochemical networks exhibit different scaling behaviors, and the network motifs found in the two systems show similarities as well as significant differences. The PageRank algorithm was used to quantify the degree to which individual species act primarily as products or reactants; in the metabolic network, these two roles are nearly identical for most species, whereas the astrochemical network shows a clearer partitioning into reactants and products.

Mathematical modeling of process calcine of oil coke on the Atyrau ORF

Process calcine represents complex physical and chemical system. The physical and chemical processes proceeding in calcines furnace, extremely complex and the majority of known laws are established at a qualitative level and have the approached character. In a domestic and foreign practice from processes calcine carbon materials hightemperature heating in rotating furnaces is most widespread. Use of methods of mathematical modelling for the analysis of static modes calcine oil coke in a rotating furnace is effective for the decision of problems of an intensification of operating process calcine.

Analysis of morphic traits between physical and chemical properties and chemical constituents based on different combinations of Shaofu Zhuyu decoction

The formulae decoctions are commonly used in clinic and have characteristics of simple preparation and rapid effect. It was considered as a complex physical and chemical system. In this article, the physical and chemical properties and chemical components and their relationships were investigated to explore the changes of characteristics resulted from different combinations of drugs of Shaofu Zhuyu decoction. The method of partial leasts-quares regression was adopted to evaluate the correlation between physical and chemical parameters and chemical components. These researches may provide a new way to investigate the state of bioactive components, the action mechanisms, and property of treating diseases of traditional Chinese medicine decoction.

Qualitative and quantitative characterization of chemical constituents in Xin-Ke-Shu preparations by liquid chromatography coupled with a LTQ Orbitrap mass spectrometer

Xin-Ke-Shu (XKS), a traditional Chinese medicine (TCM) preparation containing five herbal medicines, has been commonly used for the treatment of coronary heart disease in China. However, the chemical constituents in XKS have not been clarified yet. In order to quickly define the chemical profiles and control the quality of XKS preparations, liquid chromatography coupled with electrospray ionization hybrid linear trap quadrupole orbitrap (LC–LTQ-Orbitrap) mass spectrometry was applied for simultaneous identification and quantification of multi-constituent. A total of 51 compounds, including phenolic acids, isoflavone- C-glycosides, isoflavone- O-glycosides, flavonoids, and triterpenoid saponins, were identified or tentatively deduced on the base of their retention behaviors, MS and MS n data, or by comparing with reference substances and literatures. In addition, an optimized LC–ESI-MS method was established for quantitative determination of 15 marker compounds in XKS preparations from 7 independent pharmaceutical companies. The validation of the method, including spike recoveries, linearity, sensitivity (LOD and LOQ), precision, and repeatability, was carried out and demonstrated to be satisfied the requirements of quantitative analysis. This is the first report on the comprehensive determination of chemical constituents in XKS preparations by LC–LTQ-Orbitrap mass spectrometry. The results suggested that the established methods would be a powerful and reliable analytical tool for the characterization of multi-constituent in complex chemical system and quality control of TCM preparations.

13C-isotope labelling for the facilitated NMR analysis of a complex dynamic chemical system

(13)C-isotope labelling is presented as a novel tool for the study of complex chemical systems. (13)C-isotope labelling permits the quantification of all 26 members of a dynamic library from a single (13)C NMR spectrum without the need for advanced instrumentation or sophisticated experimental protocols.

On the nature and importance of the transition between molecules and nanocrystals: towards a chemistry of “nanoscale perfection”

This paper discusses the importance of the transition between molecular compounds and nanocrystals. The boundary between molecular and nanocrystals/nanoclusters can be defined by the emergence of the bulk phase; atoms in the core of the nanoclusters that are not bound to ligands. This transition in dimensions and structural organization is important because it overlaps with the boundary between atomically defined moieties (molecules can be isolated with increasing purity) and mixtures (nanocrystals have a distribution of sizes, shapes, and defects; they cannot be easily separated into batches of structurally identical species). Passing through this boundary, as the size of a structure increases beyond a few nanometres, the information about the position of each atom gradually disappears. This loss of structural information about a chemical structure fundamentally compromises our ability to use it as a part of a complex chemical system. If we are to engineer complex functions encoded in a chemical language, we will need pure batches of atomically defined (truly monodisperse) nanoscale compounds, and we will need to understand how to make them and preserve them over a broad range of length scales, compositions, and timeframes. In this review we survey most classes of monodisperse nanomaterials (mostly nanoclusters) and highlight the recent breakthroughs in this area which might be spearheading the development of a chemistry of "nanoscale perfection".

The virtual Product-Process Design laboratory to manage the complexity in the verification of formulated products

Formulations are complex products since active ingredients, solvents and additives are combined together to obtain a product with several functions and properties. When designing/verifying a formulated product, the required modelling effort is challenging as properties and functions of complex mixtures need to be predicted. This complexity has to be managed through decomposition of the problem into sub-problems. Each sub-problem is solved and analyzed and, from the knowledge gained, an overall evaluation of the complex chemical system representing the product is made. The virtual Product-Process Design laboratory (virtual PPD-lab) software is based on this decomposition strategy for the design of formulated liquid products. When the needed models are available in the software, the solution of formulation design/verification problems is straightforward, while when models are not available in the software library, they need to be developed and/or implemented. The potential of the virtual PPD-lab in managing the complexity in the verification of formulated products, after the needed models have been developed and implemented, is highlighted in this paper through a case study from industry dealing with the verification of a hair spray product.

Solid Phase Extraction and High Performance Liquid Chromatography for Determination of Glyoxylic Acid in a Selective Oxidation Reaction

Currently, the development of a new method for the analysis of glyoxylic acid in selective oxidation of glyoxal system has become a key subject in its new industrial process development. Since solid phase extraction (SPE) could isolate and concentrate desired analytes from complex matrices, in this paper we tested the possibility of coupling SPE technique with HPLC for simultaneous determination of glyoxylic acid, formic acid, and oxalic acid in this complex chemical reaction system. Results demonstrated that the developed method could be successfully applied to this system, after samples were passed through SAX cartridges and yielded recoveries from 96.7% to 103%. The limits of detection were 2.6 × 10−6, 3.6 × 10−6, and 3.5 × 10−7 mol L−1, respectively; and their linear ranges between 1 × 10−6 and 1 × 10−2 mol L−1.

Automated discovery of novel drug formulations using predictive iterated high throughput experimentation.

BackgroundWe consider the problem of optimizing a liposomal drug formulation: a complex chemical system with many components (e.g., elements of a lipid library) that interact nonlinearly and synergistically in ways that cannot be predicted from first principles.Methodology/Principal FindingsThe optimization criterion in our experiments was the percent encapsulation of a target drug, Amphotericin B, detected experimentally via spectrophotometric assay. Optimization of such a complex system requires strategies that efficiently discover solutions in extremely large volumes of potential experimental space. We have designed and implemented a new strategy of evolutionary design of experiments (Evo-DoE), that efficiently explores high-dimensional spaces by coupling the power of computer and statistical modeling with experimentally measured responses in an iterative loop.ConclusionsWe demonstrate how iterative looping of modeling and experimentation can quickly produce new discoveries with significantly better experimental response, and how such looping can discover the chemical landscape underlying complex chemical systems.

The Stability of Plagioclase in the Upper Mantle: Subsolidus Experiments on Fertile and Depleted Lherzolite

Plagioclase peridotites are important markers of processes that characterize the petrological and tectonic evolution of the lithospheric mantle in extensional tectonic settings. Studies on equilibrated plagioclase peridotites have documented continuous chemical changes in mantle minerals in response to plagioclase crystallization, potentially tracing the re-equilibration of mantle peridotites up to very low pressure.This experimental study provides new constraints on the stability of plagioclase in mantle peridotites as a function of bulk composition, and the compositional and modal changes in minerals occurring within the plagioclase stability field as a function of P^T^bulk composition. Subsolidus experiments have been performed at pressures ranging from 0·25 to 1·0 GPa, and temperatures ranging from 900 to 12008C on fertile and depleted anhydrous lherzolites modelled in the system TiO2^Cr2O3^Na2O^CaO^FeO^ MgO^Al2O3^SiO2 (Ti,Cr-NCFMAS). In the fertile lherzolite (Na2O/CaO 1⁄4 0·08; XCr 1⁄4 0·07) a plagioclase-bearing assemblage is stable up to 0·7 GPa, 10008C and 0·8 GPa, 11008C, whereas in the depleted lherzolite (Na2O/CaO 1⁄4 0·09; XCr 1⁄4 0·10) the upper limit of plagioclase stability is shifted to lower pressure.The boundary between plagioclase lherzolite and spinel lherzolite has a positive slope in P^T space. In a complex chemical system, the plagioclase-out boundary is multivariant and sensitive to the XCr value [XCr 1⁄4 Cr/(Cr þAl)] of spinel.This latter is controlled by the reaction MgCr2O4 þ CaAl2Si2O8 1⁄4 MgCrAlSiO6 þ CaCrAlSiO6, which is a function of the Cr^Al partitioning between spinel and pyroxenes, and varies with the XCr value and chromite/ anorthite normative ratio of the bulk composition. Within the plagioclase stability field, the Al content of pyroxenes decreases, coupled with an increase in the anorthite content in plagioclase, and Ti and XCr in spinel with decreasing pressure; these chemical variations are combined with systematic changes in modal mineralogy governed by a continuous reaction involving both plagioclase and spinel. As a consequence, the composition of plagioclase varies significantly over a rather narrow pressure range and is similar at the same P^T conditions in the investigated bulk-rocks.This suggests the potential application of plagioclase composition as a geobarometer for plagioclase peridotites.

PRECURSORS TO TITAN’S SMOG

SCIENTISTS HAVE discovered a chemical reaction that may be responsible for producing some of the orange hydrocarbon haze on Saturn’s giant moon, Titan. In a lab here on Earth, University of Hawaii, Manoa, chemistry professor Ralf I. Kaiser and an international team of colleagues show that a simple bimolecular gas-phase reaction of the ethynyl radical ( ˙ C 2 H) with diacetylene (C 4 H 2 ) produces the polyyne triacetylene (C 6 H 2 ) under ultracold conditions mimicking those on Titan ( Proc. Nat. Acad. Sci. USA 2009, 106, 16078). Such a reaction, the researchers suggest, could produce in Titan's atmosphere a ready supply of precursors to a host of more complicated polyynes. Scientists have predicted for decades that polyynes contribute to the aerosol smog that envelops the moon. Although Titan’s atmosphere is composed largely of nitrogen and methane, a complex chemical system produces the hydrocarbon aerosols that give the moon its orange-brown tinge. Models predict that polyyne chemistry dominates this s...

Chemical composition of acid–base fractions separated from biooil derived by fast pyrolysis of chicken manure

Our earlier investigations on the chemical composition of biooils derived by the fast pyrolysis of chicken manure revealed the presence of more than 500 compounds. In order to simplify this heterogeneous and complex chemical system, we produced four biooil fractions namely strongly acidic fraction A, weakly acidic fraction B, basic fraction C and neutral fraction D on the basis of their solubilities in aqueous solutions at different pHs. The yield (wt/wt.%) for fraction A was 3%, for fraction B 21.3%, for fraction C 2.4% and for fraction D 32.4%, respectively. The four fractions were analyzed by elemental analyses, Fourier Transform infrared spectrophotometry (FTIR), 1H and 13C nuclear magnetic spectroscopy (NMR), and electrospray ionization mass spectrometry (ESI-MS). The major components of the four fractions were saturated and unsaturated fatty acids, N-heterocyclics, phenols, sterols, diols and alkylbenzenes. The pH separation system produced fractions of enhanced chemical homogeneity.

The Antennal Lobes of Fungus-Growing Ants (Attini): Neuroanatomical Traits and Evolutionary Trends

Ants of the tribe Attini are characterized by their obligate cultivation of symbiotic fungi. In addition to the complex chemical communication system of ants in general, substrate selection and fungus cultivation pose high demands on the olfactory system of the Attini. Indeed, behavioral studies have shown a rich diversity of olfactory-guided behaviors and tremendous odor sensitivity has been demonstrated. To allow fine-tuned behavioral responses, adaptations within the olfactory system of the Attini are expected. We compared the number, volumes and position of the glomeruli (functional units) of the antennal lobe of 25 different species from all three major Attini groups (lower, higher and leaf-cutting Attini). The antennal lobes of all investigated Attini comprise a high number of glomeruli (>257). The highest number (630) was found in Apterostigma cf. mayri. This species is at a basal position within the Attini phylogeny, and we suggest that a high number of glomeruli might have been advantageous in the evolution of the advanced olfactory systems of the Attini. In the leaf-cutting Attini, an extremely large glomerulus (macroglomerulus) near the antennal nerve entrance was recently described in two species. Preliminary results show that this macroglomerulus is involved in processing of trail-pheromone information. In our comparative study, we find this macroglomerulus in all investigated leaf-cutting Attini, but in none of the lower and higher Attini species. It is found only in large workers, and for all investigated species it is located close to the entrance of the antennal nerve. Our results indicate that the presence of a macroglomerulus in large workers of leaf-cutting Attini is a derived over-expression of a trait in the polymorphic leaf-cutting species. It presumably represents an olfactory adaptation to elaborate foraging and mass recruitment systems, and adds to the complexity of division of labor and social organization known for this group.