scholarly journals Purification of commercial acriflavine by Sephadex LH-20 column chromatography.

1977 ◽  
Vol 25 (11) ◽  
pp. 1275-1277 ◽  
Author(s):  
J W Levinson ◽  
V M Maher ◽  
J J McCormick
Keyword(s):  
Aluminum Oxide ◽  
Column Chromatography ◽  
Spectral Properties ◽  
Absorption Maximum ◽  
Band Width ◽  
Visible Absorption ◽  
Theoretical Maximum

Acriflavine supplies commercially was purified by removing contaminating proflavine by chromatography on a column of Sephadex LH-20 eluded with 65% methanol. The purified acriflavine, recovered in a yield that was 52% of the theoretical maximum, had a visible absorption maximum of 452 nm with a band width of 47 nm. These spectral properties agreed with those of acriflavine purified by precipitation, repeated recrystallization and chromatography on aluminum oxide, which results in a yield of 13% at best.

Assay of Apocarotenal and Canthaxanthin in Foods

1966 ◽  
Vol 49 (5) ◽  
pp. 1078-1083
Author(s):  
M Osadca ◽  
E DeRitter ◽  
R H Bunnell
Keyword(s):  
Solvent Extraction ◽  
Thin Layer ◽  
Column Chromatography ◽  
Absorption Maximum ◽  
Iodine Solution ◽  
Selective Solvent ◽  
Naturally Occurring ◽  
Selective Solvent Extraction ◽  
Coloring Agents

Abstract Methods are presented for determining the carotenoids β-apo-8′-carotenaI and canthaxanthin in foods to which they have been added as colorants. They are extracted by blending or by shaking with appropriate solvents, depending on the nature of the sample, and are separated from naturally occurring pigments and other added coloring agents by selective solvent extraction and/or column chromatography. Concentration is measured by spectrophotometric reading at the absorption maximum after the system is brought to isomerization equilibrium by treatment with iodine solution. Thin layer chromatographic procedures are described for confirming the identities and completeness of separation of the carotenoids.

scholarly journals Structural and Spectral Features of Selenium Nanospheres Produced by Se-Respiring Bacteria

2004 ◽  
Vol 70 (1) ◽  
pp. 52-60 ◽  
Author(s):  
Ronald S. Oremland ◽  
Mitchell J. Herbel ◽  
Jodi Switzer Blum ◽  
Sean Langley ◽  
Terry J. Beveridge ◽  
...  
Keyword(s):  
Electron Acceptor ◽  
Spectral Properties ◽  
Bacterial Species ◽  
Anaerobic Bacteria ◽  
Chemical Oxidation ◽  
Elemental Selenium ◽  
Visible Absorption ◽  
Diverse Species ◽  
Cellular Debris ◽  
Uv Visible

ABSTRACT Certain anaerobic bacteria respire toxic selenium oxyanions and in doing so produce extracellular accumulations of elemental selenium [Se(0)]. We examined three physiologically and phylogenetically diverse species of selenate- and selenite-respiring bacteria, Sulfurospirillum barnesii, Bacillus selenitireducens, and Selenihalanaerobacter shriftii, for the occurrence of this phenomenon. When grown with selenium oxyanions as the electron acceptor, all of these organisms formed extracellular granules consisting of stable, uniform nanospheres (diameter, ∼300 nm) of Se(0) having monoclinic crystalline structures. Intracellular packets of Se(0) were also noted. The number of intracellular Se(0) packets could be reduced by first growing cells with nitrate as the electron acceptor and then adding selenite ions to washed suspensions of the nitrate-grown cells. This resulted in the formation of primarily extracellular Se nanospheres. After harvesting and cleansing of cellular debris, we observed large differences in the optical properties (UV-visible absorption and Raman spectra) of purified extracellular nanospheres produced in this manner by the three different bacterial species. The spectral properties in turn differed substantially from those of amorphous Se(0) formed by chemical oxidation of H2Se and of black, vitreous Se(0) formed chemically by reduction of selenite with ascorbate. The microbial synthesis of Se(0) nanospheres results in unique, complex, compacted nanostructural arrangements of Se atoms. These arrangements probably reflect a diversity of enzymes involved in the dissimilatory reduction that are subtly different in different microbes. Remarkably, these conditions cannot be achieved by current methods of chemical synthesis.

Synthesis, Structure and Spectral Properties of Pyrylium Salts and Their Derivatives. I. 5,6-Dihydro-benzo(c)xanthylium Salts

1987 ◽  
Vol 42 (1) ◽  
pp. 43-48 ◽  
Author(s):  
T. G. Deligeorgiev ◽  
P. Nikolov ◽  
N. Tyutyulkov
Keyword(s):  
Quantum Yield ◽  
Organic Solvents ◽  
Fluorescence Quantum Yield ◽  
Spectral Properties ◽  
Absorption Maximum ◽  
Molar Absorptivity ◽  
Pyrylium Salts ◽  
Quantumchemical Calculations ◽  
Wavelength Absorption

The synthesis and spectral properties of a group of xanthylium salts are described. The longest wavelength absorption maximum in organic solvents (ethanol, 1,4-dioxane, acetonitrile) is the region 17 000-20 000 cm-1, the molar absorptivity exceeding 30 000 1 • mol-1 cm-1. The fluorescence Frank Condon transition is in the region 16 000-19 000 cm-1, the fluorescence quantum yield of some of the compounds is greater than 0.9. The relation between the structure and the spectral properties of the molecules is interpreted by means of PPP-quantumchemical calculations.

Furazolidone and Nitrofurazone in Feeds

1966 ◽  
Vol 49 (2) ◽  
pp. 325-328
Author(s):  
Loyal R Stone
Keyword(s):  
Aqueous Solution ◽  
Aluminum Oxide ◽  
Rapid Method ◽  
Column Chromatography ◽  
Collaborative Studies

Abstract Collaborative studies were continued on a rapid method for furazolidone in feeds where the drug is isolated by column chromatography and measured in aqueous solution. This procedure was extended to determine both furazolidone and nitrofurazone separately in feeds medicated with bifuran and was studied collaboratively. The activity of the aluminum oxide adsorbent in these procedures is critical. However, with a suitable lot of adsorbent, these proposed procedures are more rapid and specific than the official methods.

Occurrence of Trigonelline (N-Methyl Nicotinic Acid) in the Adductor Muscle of a Lamellibranch, the Sea Scallop (Placopecten magellanicus)

1970 ◽  
Vol 27 (3) ◽  
pp. 604-606 ◽  
Author(s):  
Doris Fraser Hiltz
Keyword(s):  
Thin Layer ◽  
Nicotinic Acid ◽  
Column Chromatography ◽  
Spectral Properties ◽  
Exchange Resin ◽  
Cation Exchange Resin ◽  
Adductor Muscle ◽  
Placopecten Magellanicus ◽  
Linear Gradient ◽  
Sea Scallop

Trigonelline, associated with its isomer homarine, has been found in amounts ranging from 0.7 to 1.3 μmoles/g in scallop adductor muscle. Separation of the two betaines was achieved by column chromatography on a cation-exchange resin, using a linear gradient of 2 N HCl into H2O. Identification of trigonelline was based on spectral properties and on behavior in thin-layer, paper, and column chromatography.

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