Chemistry Journal of Moldova

2008 Volume 3, no.1

ESTABLISHMENT OF THE ANTIOXIDANT/ANTIRADICAL ACTIVITY OF THE INHIBITORS USING THE DPPH–RADICAL

Author(s):

Maria Gonta, Gheorghe Duca, Diana Porubin


Field: Ecological chemistry
Type: Research paper
Issue: 2008 Volume 3, no.1
Pages: 118-126
Keywords: antioxidant activity, DPPH radical, inhibition rate, natural inhibitors from secondary winery materials
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Abstract (JPEG)

DOI:
dx.doi.org/10.19261/cjm.2008.03(1).01

Graphical Abstract:
This research paper presents the results of the investigation of antioxidant activities of various inhibitors, which are constituents of winery products: quercitin, rezveratrol, dihydroxyfumaric acid. Also, the antioxidant activity of tartaric and dihydroxyfumaric (DFH4) acids derivatives has been determined: sodium dihydroxyfumarate, dimethylic ester of DFH4 and dimethylic ester of tartaric acid. The enotannin extracts obtained from grape seeds have been evaluated: the non-oxidized enotannin extract Eneox and the oxidized one -Enoxil.

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THE MIXTURES OF 2.4-DINITROPHENYLHIDRAZONES OF INFERIOR CARBONYL COMPOUNDS AND THEIR HPLC SEPARATION WITH GRADIENT BINARY MIXTURES PHASES

Author(s):

Gheorghe Zgherea


Field: Analytical chemistry
Type: Research paper
Issue: 2008 Volume 3, no.1
Pages: 52-55
Keywords: acetic aldehyde, diacetyl, 2.4-dinitrophenylhidrazone, reverse phase, low polarity, gradient of mobile phase.
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Abstract (JPEG)

DOI:
dx.doi.org/10.19261/cjm.2008.03(1).02

Graphical Abstract:
Mixtures of small quantities of carbonyl compounds are presents in foods, concerning sensorial qualities. The inferior carbonyl compounds (C2-C4, boiling point <100°C) – mono and dicarbonyl – can be identified and measured their concentrations, after a separation by distillation on the water bath. They are transferred in a strongly acid solution of 2.4-dinitrophenylhidrazine (2.4-DNPH), generating a mixture of insoluble 2.4-dinitrophenylhidrazones (2.4-DNPH-ones). The 2.4-DNPH-ones are organic compounds with weak polarity, solids, crystallized, yellows and water insoluble, soluble in organic solvents. The mixture of 2.4dinitrophenylhidrazones may be separated by liquid chromatography, using the reverse phase mechanism [1-3]. This paper contains experimental and theoretical considerations to the means of separation through liquid chromatography of two synthetically and a natural mixtures that contain 2.4-DNPH-ones provided by inferior carbonyl compounds; to obtain conclude results, in the synthetically mixtures was introduce and 2.4-DNPH-ones provided by carbonyl compounds having three (acetone and propanal) and four (isobutyl aldehyde) atoms of carbon.

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CONSIDERATIONS ON LIQUID-CHROMATOGRAPHIC SEPARATION FOR AN EQUIMOLAR MIXTURE OF 2,4-DINITROPHENYLHYDRAZONES OF ACETALDEHYDE AND DIACETYL

Author(s):

Gheorghe Zgherea


Field: Analytical chemistry
Type: Research paper
Issue: 2008 Volume 3, no.1
Pages: 48-51
Keywords: acetaldehyde, diacetyl, reverses phase, polarity, percent of water, inversion of position.
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Abstract (JPEG)

DOI:
dx.doi.org/10.19261/cjm.2008.03(1).03

Graphical Abstract:
An equimolar mixture of 2.4-dinitrophenylhidrazones (2.4DNPH-ones) providing by acetaldehyde and diacetyl must be analyzed by liquid-chromatographic separation, using the mechanism of repartition with reverse phase; that full papers is for identification the optimal analytical conditions. As mobile phase are utilized various binary mixtures eluent, containing water and methanol, with 0-45% water. By the experimental studies were identified four domains of behavior and two optimal binary mixtures, with 25% and 45% water, thus this is a study on the behavior of binary mixtures mobile phases. The peaks are characterized by values of retention times and by position. The separation processes were appreciated by difference between the retention times of peaks; if the percent of water increase, the values of retention times is higher. When the percent of water is 45%, the difference between the retention times is maxim, associated with a change of peaks position.

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STUDY ON QUANTITATIVE SPECIATION, BY BCR METHOD, OF ZINC CONTENT FROM RIVER SEDIMENTS

Author(s):

Georgiana Vasile, Stanescu Bogdan, Tudor Claudia, Elena Mihaila


Field: Ecological chemistry
Type: Research paper
Issue: 2008 Volume 3, no.1
Pages: 56-61
Keywords: sediment, sequential extraction, bioavailability, zinc mobility
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Abstract (JPEG)

DOI:
dx.doi.org/10.19261/cjm.2008.03(1).04

Graphical Abstract: The present work presents the results obtained during investigation of the zinc content of the water and river sediments in an area polluted by mining activities, to provide information on the mobility and availability of this element. Sediment and water samples have been collected from significant sites in a former mining area in which with some sterile pits, which represent a major environmental hazard.

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INFLUENCE OF IODINATED OIL AND MARGARINE ON THE THYROID SYSTEM OF RATS

Author(s):

Rodica A. Sturza, Olga I. Deseatnicov, Cristina M. Popovici, Valentin S. Gudumac, Ion Nastas


Field: Ecological chemistry
Type: Research paper
Issue: 2008 Volume 3, no.1
Pages: 77-84
Keywords: Iodine deficiency, food fortification, sunflower oil, margarine, in vivo study.
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Abstract (JPEG)

DOI:
dx.doi.org/10.19261/cjm.2008.03(1).05

Graphical Abstract:
 Iodine deficiency is the most prevalent micronutrient deficiency in the world today. Food fortification is an important compliment to food-based approaches, and iodine fortification of foods as one of the strategies for the control of iodine deficiency. Manufacturing and consumption of sunflower oil fortified with iodine as well as derivative products on it basis is a perspective direction for elimination of alimentary dependent iodine deficiency disorders. The present work examines morphological changes in the thyroid system of rats at the experimental mercatholile-induced hypothyroidism. As well it determines the influence of iodinated oil and margarine on the thyroid system of rats. It specifies the safe value of iodinated oil and margarine for rats. In-vivo study demonstrated the efficacy of fortification of lipid products with iodine under iodine deficiency status.

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DIHYDROXYFUMARIC ACID TRANSFORMATION

Author(s):

Natalia Secara


Field: Physical chemistry and chemical physics
Type: Short communication
Issue: 2008 Volume 3, no.1
Pages: 127-128
Keywords: dihydroxyfumaric acid, decarboxylation, activation energy.
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Abstract (JPEG)

DOI:
dx.doi.org/10.19261/cjm.2008.03(1).06

Graphical Abstract:
This short communication presents several preliminary results obtained during kinetic investigation of dihydroxyfumaric acid decarboxylation. The reaction order towards the hydrogen ions concentration has been established, the correlation between the decarboxylation velocity and temperature has been found, the Arrhenius equation for the decarboxylation constant has been drawn.

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NITRATE-SELECTIVE ELECTRODES BASED ON THE TRINUCLEAR CHROMIUM(III) PIVALATES

Author(s):

Mihail Revenco, Mariana Martin, Waell A.A. Dayyih


Field: Analytical chemistry
Type: Research paper
Issue: 2008 Volume 3, no.1
Pages: 44-47
Keywords: Trinuclear chromium(III) pivalate, nitrate-sensors.
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Abstract (JPEG)

DOI:
dx.doi.org/10.19261/cjm.2008.03(1).07

Graphical Abstract:
The paper describes the analytical potentialities of the trinuclear chromium(III) complexes as potentiometric ionophores for the construction of electrodes sensitive to the presence of nitrate anion. The electroactive material containing 4,4’-bipyridil was synthesized in situ. The membrane was prepared using dioctylphthalate as a solvent mediator and poly (vinyl chloride) as a polymeric matrix. The electrodes presented a slope of 56 mV/decade, a low limit of detection (3,2.10-6 mol/l), an adequate lifetime (4 months), and suitable selectivity characteristics when compared with other nitrate electrodes. The good parameters of this electrode made possible its application to the determination of nitrate in different types of fertilizers.

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AB INITIO ANALYSIS OF EXCHANGE INTERACTIONS IN [V2O(BIPY)4CL2]2+ COMPLEX

Author(s):

Ivan Ogurtsov, Andrei Tihonovschi


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2008 Volume 3, no.1
Pages: 112-117
Keywords: binuclear vanadium complex, binuclear μ-oxo-bridged complex, exchange interactions, magnetic properties, theoretical ab initio study.
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Abstract (JPEG)

DOI:
dx.doi.org/10.19261/cjm.2008.03(1).08

Graphical Abstract:
The ground state was calculated to be a quintet, which means a ferromagnetic interaction between centers. The
orbitals participating in exchange interaction according to ROHF+CI calculations are two molecular orbitals consisting of vanadium d-orbitals and two molecular orbitals with main contributions from p-orbitals of bipyridine ligands perpendicular to V-V axis, vanadium d- and p-orbitals and μ-oxygen p-orbital. Calculated energy values of the multielectronic states are placed in accordance with Lande rule. The value of magnetic moment at 293K calculated for the complex in vacuum taking into consideration the Boltzmann distribution and the energies of the excited states is 3.95BM which is in accordance with experimental value of 3.99BM (for complex in acetone).

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Author(s):

V. M. Mukhin, T. G. Lupascu


Field: Ecological chemistry
Type: Research paper
Issue: 2008 Volume 3, no.1
Pages: 62-66
Keywords: activated carbon, precious metals, environment.
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DOI:
dx.doi.org/10.19261/cjm.2008.03(1).09

Graphical Abstract:
 The authors present a brief analysis of the current global situation concerning the utilization of activated carbon in various fields. The article presents data concerning the synthesis and adsorption and structure properties of new activated carbons, used for solving ecological problems. The authors investigated the newly obtained activated carbons in comparison with several AC marks known in the world. It has been shown that currently synthesized AC are competitive with foreign marks.

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Author(s):

Irina Lunga, Pavel Kintia , Stepan Shvets, Carla Bassarello, Sonia Piacente, Cosimo Pizza


Field: Natural product chemistry and synthesis
Type: Research paper
Issue: 2008 Volume 3, no.1
Pages: 89-93
Keywords: Hyoscyamus niger L., steroidal saponins.
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DOI: 
dx.doi.org/10.19261/cjm.2008.03(1).10

Graphical Abstract:
 Ten steroidal saponins have been isolated form the seeds of Hyoscyamus niger L. for the first time and their structures have been elucidated. Seven saponins belong to spirostane series, two are furostane-type and one is pregnane glycoside. Hyoscyamosides B, C and C2 are new steroidal saponins, which have never been reported before in literature. Complete assignments of the 1H and 13C NMR chemical shifts for all these glycosides were achieved by means of one- and two-dimensional NMR techniques, including 1H–1H COSY, HSQC, HMBC and ROESY spectra.

Downloads: 12