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Chemistry Central Journal publishes peer-reviewed open access research in chemistry. Chemistry Central is part of the BioMed Central group
Background:
Chimonanthus nitens (family Calycanthaceae), Shanlamei in Chinese, is an unique species in China. The extract of dried leaves of Chimonanthus nitens has anti-inflammatory, antipyretic and antitussive effects. Terpenes, coumarins, and flavonoids are usually regarded as the main active components. Therefore, simultaneous determination of these compounds is very important to control the quality of Chimonanthus nitens.
Results:
A double-development TLC method was developed for simultaneous analysis of five compounds in Chimonanthus nitens. The chromatography was performed on silica gel 60 plate with chloroform-methanol (91, v/v) and petroleum ether-ethyl acetate (101, v/v) as mobile phase for twice development. Their characteristic TLC profiles were observed under UV light at 365 nm and the bands were then revealed by reaction with 1% vanillin-H2SO4 solution. Quantification of three monoterpenes was achieved by densitometry at 545 nm (beta-caryophyllene) or 606 nm (cineole and linalool). Two coumarins (scopoletin and scoparone) were determined by densitometry at 340 nm with filter wavelength of 370 nm. The investigated compounds had good linearity (R2 >0.99) within test ranges.
Conclusions:
The developed double-development TLC method is helpful to control the quality of Chimonanthus nitens, which is simple and accurate.
Background:
Establishing the distribution of materials in paintings and that of their degradation products by imaging techniques is fundamental to understand the painting technique and can improve our knowledge on the conservation status of the painting. The combined use of chromatographic-mass spectrometric techniques, such as GC/MS or Py/GC/MS, and the chemical mapping of functional groups by imaging SR FTIR in transmission mode on thin sections and SR XRD line scans will be presented as a suitable approach to have a detailed characterisation of the materials in a paint sample, assuring their localisation in the sample build-up. This analytical approach has been used to study samples from Catalan paintings by Josep Maria Sert y Badia (20th century), a muralist achieving international recognition whose canvases adorned international buildings.
Results:
The pigments used by the painter as well as the organic materials used as binders and varnishes could be identified by means of conventional techniques. The distribution of these materials by means of Synchrotron Radiation based techniques allowed to establish the mixtures used by the painter depending on the purpose.
Conclusions:
Results show the suitability of the combined use of SR FTIR and SR XRD mapping and conventional techniques to unequivocally identify all the materials present in the sample and their localization in the sample build-up. This kind of approach becomes indispensable to solve the challenge of micro heterogeneous samples. The complementary interpretation of the data obtained with all the different techniques allowed the characterization of both organic and inorganic materials in the samples layer by layer as well as to establish the painting techniques used by Sert in the works-of-art under study.
The aim of this work was to study the Altar Machine in the Church Mother of Gangi, a little town near Palermo (Italy) regarding the history, the technical manufacture, the constitutive materials and the state of preservation.The Altar Machine was dated back to the second half of the 18th century, it is constituted by carved and painted wood, a complex system of winch and pulleys allows moving various statues and parts of the Machine in accordance with the baroque scenography machineries. The Machine is a particularly delicate system made of several materials: wood, pigments, binders, gilding, so the study and characterization of the constitutive materials has been required also in anticipation of a probable conservation project. To support the project, a short microclimate campaign was carried out in August, the most critical period for the artefact. In fact, summer sultriness is particularly high during August. Moreover in August the Machine is moved on the occasion of religious celebrations and many people crowd the church thus influencing the microclimate.The observation and survey of the mechanisms allowed formulating hypothesis on a more ancient mode of operation of the Altar Machine.Stratigraphic and chemical analysis revealed the presence of many superimposed layers constituted by several different materials (protein binders, siccative oils, natural terpene resins, shellac, calcium carbonate, gypsum, zinc white, iron oxides). For these kind of artefacts it is usual to find many superimposed painted layers due to a continuous usage of the object that has got a demo-ethno-anthropological significance.Regarding relative humidity (RH) and temperature (T) monitoring, it is generally possible to assess that most of the data fall outside the tolerance intervals, i.e. the RH and T limits defined by the international standards. High values of temperature can favour the biotic attack. Moreover, graphs of T and RH as function of time showed that T values were generally high (out of the tolerance range) but they appeared to be quite constant; on the other hand RH values fell almost always inside the tolerance area but they often exhibited dangerous variations.
Background:
For millennia, iron-tannate dyes have been used to colour ceremonial and domestic objects shades of black, grey, or brown. Surviving iron-tannate dyed objects are part of our cultural heritage but their existence is threatened by the dye itself which can accelerate oxidation and acid hydrolysis of the substrate. This causes many iron-tannate dyed textiles to discolour and decrease in tensile strength and flexibility at a faster rate than equivalent undyed textiles. The current lack of suitable stabilisation treatments means that many historic iron-tannate dyed objects are rapidly crumbling to dust with the knowledge and value they hold being lost forever.This paper describes the production, characterisation, and validation of model iron-tannate dyed textiles as substitutes for historic iron-tannate dyed textiles in the development of stabilisation treatments. Spectrophotometry, surface pH, tensile testing, SEM-EDX, and XRF have been used to characterise the model textiles.
Results:
On application to textiles, the model dyes imparted mid to dark blue-grey colouration, an immediate tensile strength loss of the textiles and an increase in surface acidity. The dyes introduced significant quantities of iron into the textiles which was distributed in the exterior and interior of the cotton, abaca, and silk fibres but only in the exterior of the wool fibres. As seen with historic iron tannate dyed objects, the dyed cotton, abaca, and silk textiles lost tensile strength faster and more significantly than undyed equivalents during accelerated thermal ageing and all of the dyed model textiles, most notably the cotton, discoloured more than the undyed equivalents on ageing.
Conclusions:
The abaca, cotton, and silk model textiles are judged to be suitable for use as substitutes for cultural heritage materials in the testing of stabilisation treatments.
Background:
Launaea procumbens (LP) has been used as a food supplement in Pakistan. In this study methanolic crude extract (LPME) of the whole plant and its different fractions; n-hexane (LPHE); ethyl acetate (LPEE) and chloroform (LPCE) were studied for the determination of total flavonoid and phenolics contents along with multifaceted in vitro scavenging assays.
Results:
Considerable amount of flavonoid and phenolics contents were found in all the fractions. Methanol and chloroform fraction exhibited efficient scavenging of DPPH * , ABTS * +, * OH, superoxide, lipid peroxide and nitric oxide free radicals. Significant correlation was found between DPPH * , ABTS * +, superoxide radical, beta-carotene bleaching restraint and phosphomolybdenum assay with total flavonoids and phenolics contents. High performance chromatography (HPLC) of LPME revealed the presence of vitexin, orientin, rutin, hyperoside, catechin and myricetin.
Conclusion:
These results reveal the presence of bioactive compounds in LPME, which might be contributed towards the various in vitro scavenging.Key words: Launaea procumbens, scavenging of DPPH-free radicals, Superoxide radicals,HPLC, Flavonoids
Background; A sampling campaign of indoor air was conducted to assess the typical concentration of indoor air pollutants in 8 National Libraries and Archives across the U.K. and Ireland. At each site, two locations were chosen that contained various objects in the collection (paper, parchment, microfilm, photographic material etc.) and one location was chosen to act as a sampling reference location (placed in a corridor or entrance hallway). Results and Discussion; Of the locations surveyed, no measurable levels of sulfur dioxide were detected and low formaldehyde vapour (< 18 ug m-3) was measured throughout. Acetic and formic acids were measured in all locations with, for the most part, higher acetic acid levels in areas with objects compared to reference locations. A large variety of volatile organic compounds (VOCs) was measured in all locations, in variable concentrations, however furfural was the only VOC to be identified consistently at higher concentration in locations with paper-based collections, compared to those locations without objects. To cross-reference the sampling data with VOCs emitted directly from books, further studies were conducted to assess emissions from paper using solid phase microextraction fibres (SPME) fibres and a newly developed method of analysis; collection of VOCs onto a polydimethylsiloxane (PDMS) elastomer strip. Conclusions; In this study acetic acid and furfural levels were consistently higher in concentration when measured in locations which contained paper-based items. It is therefore suggested that both acetic acid and furfural (possibly also trimethylbenzenes, ethyltoluene, decane and camphor) may be present in the indoor atmosphere as a result of cellulose degradation and together may act as an inferential non-invasive marker for the deterioration of paper. Direct VOC sampling was successfully achieved using SPME fibres and analytes found in the indoor air were also identified as emissive by-products from paper. Finally a new non-invasive, method of VOC collection using PDMS strips was shown to be an effective, economical and efficient way of examining VOC emissions directly from the pages of a book and confirmed that toluene, furfural, benzaldehyde, ethylhexanol, nonanal and decanal were the most concentrated VOCs emitted directly from paper measured in this study.
Background:
Naringin is an important flavanone with several biological activities, including antioxidant action. However, this compound shows low solubility in lipophilic preparations, such as is used in the cosmetic and food industries. One way to solve this problem is to add fatty acids to the flavonoid sugar unit using immobilized lipase. However, there is limited research regarding hydroxylation of unsaturated fatty acids as an answer to the low solubility challenge. In this work, we describe the reaction of naringin with castor oil containing ricinoleic acid, castor oil's major fatty acid component, using immobilized lipase from Candida antarctica. Analysis of the 1H and 13 C NMR (1D and 2D) spectra and literature comparison were used to characterise the obtained acyl derivative.
Results:
After allowing the reaction to continue for 120 hours (in acetone media, 50degreesC), the major product obtained was naringin 6"-ricinoleate. In this reaction, either castor oil or pure ricinoleic acid was used as the acylating agent, providing a 33% or 24% yield, respectively. The chemical structure of naringin 6"-ricinoleate was determined using NMR analysis, including bidimensional (2D) experiments.
Conclusion:
Using immobilized lipase from C. antarctica, the best conversion reaction was observed using castor oil containing ricinoleic acid as the acylating agent rather than an isolated fatty acid.
Due to the increasing industrial use of titanium compounds, its determination is the subject of considerable efforts. The ionophore or the membrane active recognition is the most important component of any polymeric membrane sensor. The sensor respond depends on the ionophore and bonding between the ionophore and the target ion. Ionophores with molecule-sized dimensions containing cavities or semi-cavities can surround the target ion. The bond between ionophore and target ion gives different selectivity and sensitivity toward the other ions. Therefore, ionophores with different binding strengths can be used in the sensor. In the present work, poly(vinyl chloride) (PVC) based membrane incorporating tris(2 pyridyl) methylamine (tpm) as an ionophore have been prepared and explored as a titanium(III) selective sensor. The strengths of the ion-ionophore (Ti(OH)2+-tpm) interactions and the role of ionophore on membrane was performed by various techniques such as elemental analysis, UV-Vis, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and powder X-ray diffraction (XRD). All data approve the successful incorporation of organic group via covalent bond.
Three new lanostane-type triterpene acids, 3-epi-benzoyloxyl-dehydrotumulosic acid (1), 3-epi-(3'-O-methyl malonyloxy)-dehydrotumulosic acid (2) and 3-epi-(3'-hydroxy-3'-methylglutaryloxyl)-dehydrotumulosic acid (3), were isolated from the sclerotia of Wolfiporia extensa, together with 3 known lanostane derivatives (4-6). Their structures were elucidated on the basis of spectroscopic analysis, including 1D and 2D-NMR techniques.
Two new monocyclic monoterpenoid glycosides, rel-(1R,2S,3R,4R) p-menthane-1,2,3-triol 3-O--D-glucopyranoside (1) and rel- (1S,2R,3S) terpinolene-1,2,3-triol 3-O--D-glucopyranoside (2) were isolated from aqueous acetone extract of the aerial parts of Mentha haplocalyx. Their structures were elucidated through spectral analysis using MS and NMR spectrometers.
Posted on 6 May 2012 | 2:00 am
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