Inhibition Role of Solvation on the Selective Extraction of Co(II): Toward Eco-Friendly Separation of Ni and Co

Using the methods of selective extraction, atomic absorption, and gas-liquid chromatography, we determined that the river and lake waters in arid and/or humid regions differ in their total and alkylated mercury content indices. Mercury high content levels in waters of arid landscapes (e.g., in Kyrgyzstan) do not activate metal methylation process. The features of the interaction of mercury and humic compounds like fulvic (FA) and humic (HA) acids are discussed. The FA are found to promote mercury dispersion in the biosphere due to the formation of fulvic complexes and abiogenic methylation of mercury resulting in the toxic organomercuric compounds. The HA manifest high sorption capacity levels in relation to mercury ions and serve as sorbents. At a competitive interaction in the system FA-Нg-HA, Кd for mercury drops sharply with an increase in FA concentration and рН system. The metabolism of mercury in the biosphere in terms of its content in the soilplant complex is discussed.

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A structural role of the carotenoid in the light-harvesting II protein of Rhodobacter capsulatus

Biochemical Journal ◽

10.1042/bj2900531 ◽

1993 ◽

Vol 290 (2) ◽

pp. 531-537 ◽

Cited By ~ 25

Author(s):

J Zurdo ◽

C Fernandez-Cabrera ◽

J M Ramirez

Keyword(s):

Structural Changes ◽

Rhodobacter Capsulatus ◽

Light Harvesting ◽

Bathochromic Shift ◽

Selective Extraction ◽

Experimental Manipulation ◽

Exchange Chromatography ◽

Residual Fraction ◽

Independent Effect

The membrane-linked light-harvesting II protein (LHII) of Rhodobacter capsulatus was partly depleted of carotenoids by selective extraction with light petroleum. Carotenoid removal was accompanied by bleaching of the Qy(S1<--S0) absorption band of bacteriochlorophyll (Bchl) a near 800 nm, by a bathochromic shift and a broadening of the other Bchl Qy band at 850 nm, and by the formation of a weak Qy band of dissociated Bchl near 770 nm. The changes in the 800 and 850 nm bands seemed to reflect alterations in only those Bchl molecules that had lost their associated carotenoids, firstly, because the extent of the changes was closely correlated to the degree of carotenoid extraction, and, secondly, because the residual fraction of carotenoid-containing LHII, which could be almost quantitatively recovered from the membrane after detergent solubilization and ion-exchange chromatography, showed an unmodified LHII absorption spectrum. The Bchl responsible for the shifted 850 nm band remained bound to protein, since its visible (Qx) transition seemed to retain the induced optical activity of the native bound pigment. Besides, the shifted Bchl could act as an efficient acceptor of singlet excitation energy from the pigments of the intact LHII fraction. The close similarity between the spectroscopic Bchl changes that accompany carotenoid extraction and the differential spectral features of carotenoidless LHII of Rhodobacter mutants, previously reported, strongly suggests that the direct cause of the spectral modifications is the absence of carotenoid and not any independent effect of the experimental manipulation of the membrane. Several interpretations of the structural changes that underlie the observed spectral changes are possible. The simplest one is to assume that carotenoid removal elicits an alteration in the angle between the Qy transition moments of two strongly interacting Bchl molecules.

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POLYPHENOLS OF BROWN ALGAE

chemistry of plant raw material ◽

10.14258/jcprm.2018031898 ◽

2018 ◽

pp. 5-21 ◽

Cited By ~ 3

Author(s):

Константин (Konstantin) Григорьевич (Grigor'evich) Боголицын (Bogolitsyn) ◽

Анна (Аnna) Сергеевна (Sergeevna) Дружинина (Druzhinina) ◽

Денис (Denis) Владимирович (Vladimirovich) Овчинников (Ovchinnikov) ◽

Платон (Platon) Александрович (Aleksandrovich) Каплицин (Kaplitsin) ◽

Елена (Elena) Валерьевна (Valer'evna) Шульгина (Shulgina) ◽

...

Keyword(s):

Brown Algae ◽

Solid Phase ◽

Gel Permeation Chromatography ◽

Selective Extraction ◽

Polyphenolic Compounds ◽

Polymer Composition ◽

Resonance Spectroscopy ◽

State Of Research ◽

Ionization Methods

The modern state of research of marine brown algae polyphenolic compounds – phlorotannins, is analyzed. The data on the content of phlorotannins in biomass are presented depending on the species of algae and the place of growth. The biosynthesis, morphology, accumulation in the thallus, the physicochemical properties and biological role of these compounds are considered. The classical methods of isolating phlorotannins from algae are described, as well as modern methods, such as ultrasonic, microwave, enzymatic extraction, liquid extraction under pressure and supercritical fluid extraction. The ways of selective extraction of these compounds from extracts by methods of liquid-phase and solid-phase extraction are considered. Methods for studying the polymer composition of phlorotannins like gel permeation chromatography and ultrafiltration are presented. In the review of methods for quantitative determination and structural analysis of phlorotannins, special attention is paid to methods of nuclear magnetic resonance spectroscopy and chromatography-mass spectrometry using various ionization methods. The significant biological activity of phlorotannins is shown, which is represented by antioxidant, antitumor, anti-inflammatory, antibacterial, antiviral and other activities, which determines the prospects for the practical application of these polyphenolic compounds as therapeutic and prophylactic agents in the food, cosmetic and pharmacological industries.

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Cell Wall Degradation in Irradiated Tomato Fruit

HortScience ◽

10.21273/hortsci.30.4.815b ◽

1995 ◽

Vol 30 (4) ◽

pp. 815B-815

Author(s):

N. El-Assi ◽

D.J. Huber ◽

J.K. Brecht

Keyword(s):

Cell Wall ◽

Tomato Fruit ◽

Selective Extraction ◽

Specific Cell ◽

Neutral Sugar ◽

Cell Wall Degradation ◽

X Ray ◽

Green Fruit ◽

Cell Wall Polymers

The irradiation of harvested fruit is typically accompanied by excessive tissue softening, a process that is not well understood. In this study, we examined the role of specific cell wall polymers and the extent of general cell wall degradation and softening in irradiated tomato fruit. `Sunny' tomato fruit at mature-green and pink stages were subjected to X-ray radiation at 0, 83, and 156 Krad. Immediate softening was noted for both maturation classes, although some postirradiation recovery was evident in green fruit. Pectic polymers of both mature-green and pink fruit exhibited depolymerization and altered neutral sugar profiles in response to irradiation. Pectins, either as components of total ethanol-insoluble solids (EIS), purified by selective extraction, or of commercial origin were similarly affected by irradiation. Cellulose preparations were unaffected by irradiation. The data demonstrate that the effect of irradiation on the cell wall exhibits specificity, can occur nonenzymatically, and does not require initiating adducts of cytosolic origin.

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Rapid liquid-liquid extraction of thallium(III) from succinate media with 2-octylaminopyridine in chloroform as the extractant

Journal of the Serbian Chemical Society ◽

10.2298/jsc0804435m ◽

2008 ◽

Vol 73 (4) ◽

pp. 435-451 ◽

Cited By ~ 6

Author(s):

Sandip Mahamuni ◽

Prakash Wadgaonkar ◽

Mansing Anuse

Keyword(s):

Sodium Succinate ◽

Volume Ratio ◽

Selective Extraction ◽

Analysis Method ◽

Extraction Equilibrium ◽

Slope Analysis ◽

Liquid Liquid Extraction ◽

Extraction Study ◽

Quantitative Extraction

A simple solvent extraction study of thallium(III) was conducted. Selective and quantitative extraction of thallium(III) by 2-octylaminopyridine (2-OAP) in chloroform occurred from aqueous sodium succinate medium (0.0075 M) at pH 3.0. Thallium(III) was back extracted with acetate buffer (pH 4.63). The effect of the concentration of succinate and 2-OAP, the role of various diluents, stripping agents, loading capacity of 2-OAP, equilibrium time and aqueous:organic volume ratio on the extraction of thallium(III) was studied. The stoichiometry of the extracted species was determined based on the slope analysis method and found to be 1: 2: 1 (metal:acid:extractant). The temperature dependence of the extraction equilibrium constant was also examined to estimate the apparent thermodynamic functions ?H, ?G and ?S for the extraction reaction. The method is free from interference of a large number of cations and anions. The method was used for the selective extraction of thallium(III) from its binary mixture with Zn(II), Cd(II), Hg(II), Bi(III), Pb(II), Se(IV), Te(IV), Sb(III), Ga(III), In(III), Al(III), Tl(I) and Fe(III). The proposed method was applied to the synthetic mixtures and alloys. It is simple, selective, rapid and eco-friendly.

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On the paucity of amorphous minerals in the sensitive postglacial marine clays

Canadian Geotechnical Journal ◽

10.1139/t95-054 ◽

1995 ◽

Vol 32 (3) ◽

pp. 535-538 ◽

Cited By ~ 7

Author(s):

J. Kenneth Torrance

Keyword(s):

Key Words ◽

Iron Oxides ◽

Mineral Content ◽

Extraction Procedure ◽

Selective Extraction ◽

Eastern Canada ◽

Oxide Minerals ◽

Marine Clays ◽

Amorphous Minerals

The abundance and role of amorphous minerals in the sensitive marine clays of eastern Canada has been a subject of investigation since 1974. Unfortunately, the Segalen "selective" extraction procedure (alternating HCl and NaOH), which was used in most of the experiments, is very aggressive. By attacking both oxide minerals (which were presumed to be amorphous) and crystalline phyllosilicates, its use led to major overestimates of the possible amorphous mineral content. Less aggressive "selective" extraction procedures indicate that less than 1% of the sensitive Champlain Sea sediments is oxide minerals, and Mössbauer spectroscopy has detected only crystalline iron oxides, which are probably of detrital origin. The amount of amorphous oxide minerals is at most a small fraction of 1%. Crystalline iron oxides, in the concentrations naturally present, have been demonstrated to influence the rheology of the sensitive marine clays, but it seems improbable that the very small amounts of amorphous minerals that may be present are geotechnically important. Key words : sensitive marine clays, iron oxides, amorphous minerals, selective extraction.

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