Detection of carboxylic acid group in organic compounds with eosin, mercurochrome, and methylene blue

Summary The dyes mercurochrome and eosin have been used alone and in combination with methylene blue for the detection of carboxlic acid group in organic compounds. In the first, single dye test, a dilute solution of mercurochrome (or eosin) gives a red or orange-coloured precipitate on treatment with a solution of carboxylic acid in water, acetone, alcohol, or dioxan. In the second, mixed dye test, the highly intense green fluorescence produced by mixing a dilute solution of mercurochrome or eosin with a dilute solution of methylene blue, is completely destroyed when a little carboxylic acid is added. Other acidic compounds such as phenols, sulphonamides, acid imides etc. do not interfere. Sulphonic acids, enols and salts of organic bases, however, cause interferences. The general limits of detection are 1 mg and 2 mg carboxylic acid compound in a drop (0.05 ml) in the single dye and mixed dye tests respectively.

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Nachweis von Carboxylgruppen in organischen Verbindungen mit Hilfe von Eosin, Mercurochrom und Methylenblau

Zusammenfassung Mercurochrom und Eosin wurden allein und in Kombination mit Methylenblau zum Nachweis von Carboxylgruppen verwendet. Im ersten Fall erhält man einen roten oder orangefarbenen Niederschlag, wenn man die verdünnte Farbstofflösung mit der in Wasser, Aceton, Alkohol oder Dioxan gelösten Probe versetzt. Im zweiten Fall wird die intensiv grüne Fluorescenz, die durch Mischen von Mercurochrom (oder Eosin) mit Methylenblau entsteht, durch Zusatz der Probe zerstört. Phenole, Sulfonamide, Säureimide u. ä. stören nicht, jedoch Sulfonsäuren, Enole und Salze organischer Basen.

     

Interaction of an Endosomolytic Polyamidoamine ISA23 with Vesicles Mimicking Intracellular Membranes: A SANS/EPR Study

The mechanism of ISA23 · HCl interaction with model membrane vesicles (80–100 nm in diameter) was investigated using EPR in conjunction with SANS. For EPR, 16‐DSE was dissolved in the vesicle membrane to measure its dynamics and polarity, whereas a spin‐labeled (Tempo)‐ISA 23 analogue was used to give a measure of the polymer flexibility. When ISA23 was added to the external vesicle surface, no interaction was found. This observation conflicts with the reported ability to lyse RBC, but is in agreement with recent studies that showed no effect on membrane permeability when a PAA was added to an incubation medium containing isolated lysosomal vesicles. The vesicle‐mimetic models used here provide a new and useful tool for studying endosomolytic polymer/membrane interactions.

     

Synthesis and carboxylate anion binding studies on cyclic sugar-amino acid hybrids

Abstract

Here in, the condensation of boc-glycine with 2,6-anhydro-3,4,5-tri-O-benzyl-D-gluco-heptitol followed by its boc-deprotection to form 2,6-anhydro-3,4,5-tri-O-benzyl-D-gluco-heptitolyl bis-glycinate, which in turn on condensation with succinic acid/pyridine-2,6-dicarboxylic acid led to the formation of sugar-amino acid hybrid macrocyclic compounds 4, 6 and debenzylated marocyclic compound 5, having amide bonds that function as efficient host for polar, hydrogen bond acceptors and carboxylate ions. The anion inclusion capability of synthesized macrocylic hosts has been evaluated by the study of their binding with boc-GlyCOOˉ anion as guest through 1H NMR titration studies in CDCl₃. The binding constant (K_a) of boc-GlyCOOˉ guest with macrocyclic hosts 4 and 6 involving succinate and pyridine-2,6-dicarboxylate linkers was found to be 9.201?×?10³ and 1.437?×?10⁴ M^?1, respectively. The higher binding constant was observed in the complex of boc-GlyCOOˉ with pyridine-dicarboxylate containing host may be due to the extra rigidity & suitable conformation attained by the presence of rigid-aromatic dicarboxylate linker.     

New spot tests for thallium(I), bismuth(III), and iodide

Microchimica Acta - New spot tests are described for the selective detection of Tl(I), Bi(III), and I? ions, with limits of detection 4 μg, 5 μg, and 15 μg respectively, and...     

DC electrical conductivity of semiconducting cobalt-phosphate glasses

The dc conductivity of semiconducting cobalt-phosphate glasses has been measured at temperatures ranging from 213 to 530 K. Four bulk samples of CoO-P₂O₅ glasses of different compositions were produced by melting dry mixtures of analytical reagent grades of CoO and P₂O₅ at temperatures between 1200-1250 °C for 2 h using a press-quenching method from glass melt. Samples were annealed at 400 °C for 1 h. The dc conductivity was found to be dependent on the CoO content in the glass. At temperatures from 213 to 444 K, however, both Mott's variable-range hopping (VRH) and the Greaves' intermediate range hopping models are found to be applicable. VRH at this range of temperatures is attributed to large values of the disorder energy of these glasses.     

Sequential effects of ultraviolet radiation on the histomorphology, cell density and antioxidative status of the lens epithelium--an in vivo study

In vivo progressive effects of UV irradiation on the lens epithelium were studied using various histomorphological and biochemical parameters. Fifteen day old rat pups were exposed to 600 mW/m2 of radiation, including UV-A and UV-B, 12 h daily for 90, 120, 150 and 180 days. Biochemical parameters such as protein-bound and non-protein-bound sulfhydryl groups in both soluble and insoluble fractions and enzymes, which play an important role in combating the oxidative stress, were studied. Decreased cell density of lens epithelial cells (LEC) was observed in all three zones along with the decrease in the levels of soluble sulfhydryls (S-SH), glutathione reductase (GR), superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT). On the other hand, an increase in insoluble sulfhydryls was observed. Because of the decrease in S-SH and GR activities, the LEC became vulnerable to oxidative stress. Decreased activities of SOD, GPx and CAT suggest elevated oxidative stress. This effect of UV radiation may lead to cell death that may be responsible for the observed decrease in the cell density in all three zones of the lens epithelium.