Thin-Layer Chromatographic Studies of 30 Organic Acids on Calcium Sulphate

Abstract

Thin layer chromatographic behaviour of 30 organic acids on coatings of calcium sulphate and calcium sulphate containing charcoal, p-dimethyl-aminobenzaldehyde, flyash, silica gel G etc. has been studied. Farm chemicals: plant growth regulators (benzoic, cinnamic, gallic, β-naphthalene acetic, β-naphthoxy acetic and indole-3-acetic acids) and herbicides (phenoxy acetic acid) have been separated from one another and from several other organic acids.     

Sequential Thin-Layer Chromatography of 2,4-D and Related Compounds

Abstract

Separations and identification of carboxylic herbicidal substances such as 2,4-dichlorophenoxyacetic acid, trichloroacetic acid, 2,4,5-trichlorophenoxyacetic acid and plant growth regulators such as benzoic acid, cinnamic acid, indole-3-acetic acid, β-naphthaleneacetic acid, β-naphthoxyacetic acid, phenoxyacetic acid have been made by sequential thin-layer chromatography on calcium sulphate layer with acetone, benzene, carbon tetrachloride, chloroform, ethyl acetate, dioxan, propanol as solvents and bromophenol blue as detector.     

Separation of Some Herbicides by Two Dimensional Thin Layer Chromatography on Calcium Sulphate

Abstract

Two dimensional thin layer chromatography is being used for the last forty years¹ and now it has became an important tool for the separations of varying complexity. Various coating materials such as alumina, cellulose, kieselgel G, silica gel, silufol and polyamide have been used and studied for the separation of organics such as alkaloids, amino acids, carbohydrates, fatty acids, glycopeptides, glycolipids, lipids, phospholipids, pigments, protiens, peptides, pesticides, steroids and inorganics such as oxy acids of phosphorus, metal ions. Our previous work^{2′3′4′5′6} shows that calcium sulphate coated paper and glass plates have a great separation potential for herbicides containing carboxyl group. Therefore now an attempt is made to test the separation potential of calcium sulphate alone and calcium sulphate containing aluminium oxide active neutral, calcium carbonate and p-dimethylaminobenzaldehyde for some nerbicides by two dimensional thin layer chromatography. The results obtained are discxissed in this paper.     

Electrophoretic Behaviour of 34 Organic Acids on Impregnated Strips

Abstract

Electrophoretic behaviour of 34 organic acids on calcium sulphate impregnated papers has been studied. The 19 binary separations in aqueous sodium chloride and sodium sulphate solutions and distilled water have been achieved.     

Effects of different metal salts of aliphatic dicarboxylic acids on the formation of β-crystalline form in isotactic polypropylene

The effects of barium, calcium and zinc salts of the aliphatic dicarboxylic acids on the nucleation ability and formation of β-crystalline form in isotactic polypropylene (iPP) were investigated. The results showed that barium, calcium and zinc salts of aliphatic dicarboxylic acid were related to the number of carbon atoms in the acids, and carbon atomic numbers of 5–8 had good nucleation ability for iPP except calcium adipate and zinc pimelate, in which barium glutarate, calcium suberate and zinc suberate were highly efficient β-nucleating agents for iPP. In addition, the optimal addition amounts of barium glutarate, calcium suberate and zinc suberate were 0.1 mass%, 0.1 mass% and 0.15 mass%, respectively, and the relative contents of β-crystals reached 0.9561, 0.9351 and 0.9447, respectively. The results of mechanical and thermal properties with the optimal addition amount showed that barium glutarate, calcium suberate and zinc suberate improved the toughness and thermal properties but decreased the rigidity of iPP.

     

Paper Chromatography of 34 Organic Acids on Calcium Carbonate and Calcium Sulphate Impregnated Papers

Abstract

Paper chromatographic separations of 34 organic acids on calcium carbonate and calcium sulphate impregnated paper has been developed. Tricarboxylic acids, dicarboxylic acids, amino acids, and keto acids and their derivatives can be separated in simple solvents such as acetone, ethanol, water, aqueous sodium chloride, ammonium chloride and calcium nitrate. Important separations achieved are: Adipic from maleic and malonic, cis-aconitic from I-cystine and nicotinic, citric or tartaric from ascorbic, gallic, malic and salicylic, I-aspartic from arginine-HCl, fumaric and glutamic, barbituric from hippuric and α-ketoglutaric, benzoic from ρ- & m-nitrobenzoic and cis-aconitic from trans-aconitic.     

Reaction of Amino Acid Esters and Amides with o-Phthalaldehyde. Limitations in Fluorescent Yield

Abstract

Amino acid esters and amides fail to produce strong fluorescence following their reaction with o-phthalaldehyde (OPA) in the presence of β-mercaptoethanol. The lack of luminescence appears to arise from a quenching phenomenon rather than from reduced reactivity of these substrates toward OPA. The amido hydrogen in the peptide linkage has been implicated in the loss in fluorescence yield.

o-Phthalaldehyde (OPA) has proven to be a very useful reagent for converting amino acids to fluorescent isoindole derivatives¹. This derivatization process permits the visualization of femtomolar quantities of amino acids. Unfortunately, this technique has not been applied successfully to the derivatization of peptides^2,3, except for those containing lysine residues, in which the terminal amino group is attacked by the reagent⁴. It is the purpose of this note to more clearly define the limitations of OPA as a fluorogenic reagents for peptides and amino acid esters.     

High-Performance Liquid Chromatographic Behavior of 2-,4- and 6-Hydroxylated Bile Acid Stereoisomers

Abstract

High-performance liquid chromatographic behavior has been investigated for 40 stereoisomeric 2-, 4- and 6-hydroxylated bile acids, most of which possess a vicinal glycol structure, as their 4-nitrophthalimidomethyl (NPM) ester derivatives on a reversed-phase column using methanol-water systems as a mobile phase. The bile acid NPM esters were further derivatized to the so-called “mixed” acetonide-NPM esters, whereby the stereochemical relationships (α, α-and β,β-cis, diaxial trans or diequatorial trans) of 2,3-, 3,4-and 6,7-diol groups in the molecules were reflected to changes in the capacity factors of bile acids.     

Cerate-chromate oxidimetry

Summary Oxalic acid is oxidised to carbon dioxide and water with sulphatocerate in dilute sulphuric acid medium. Formic acid is not affected by ceric sulphate under the above conditions. Both oxalic and formic acids are quantitatively oxidised to carbon dioxide and water by the cerate-chromate reagent. Based on this principle a method has been suggested for the estimation of a mixture of oxalic and formic acids.Part I: see Z. analyt. Chem. 154, 340 (1957).     

Determination of Hydrofluoric Acid in Mixed Acids with an Acid Concentration Meter

Abstract

A commercial acid concentration meter containing an N-type silicon anode and stainless cathode has been used to selectively measure hydrofluoric acid in mixtures containing nitric, phosphoric and sulfuric acids. At very high weight ratios of acid to HF (> 10:1) a suppression in HF response was noted for all acids examined. At lower ratios or higher HF values only nitric acid influences HF response with a sensitizing or catalytic effect not appreciably dependent on HNO, concentration.     

The Paper Electrophoresis of Alkaloids with Strong Acids as Electrolytes

Abstract

Some alkaloids were studied by paper electrophoresis using strong acids (0.1 N and 0.5 N) as electrolyte. There are differences in the separations obtained depending on the acid. Perchloric acid and trichloroacetic acid gave the best separations.     

Partial molar volumes and adiabatic compressibilities at infinite dilution of aminocarboxylic acids and glycylglycine in water and aqueous solutions of sodium sulphate at (288.15, 298.15 and 308.15) K

The partial molar volume and partial molar adiabatic compressibilities at infinite dilution of dl-aminobutanoic acid, dl-norvaline, β-alanine, 4-aminobutanoic acid, 5-aminopentanoic acid, 6-aminohexanoic acid and glycylglycine have been obtained in water and aqueous solutions of (0.5, 1.0 and 1.5) mol · kg⁻¹ sodium sulphate at (288.15, 298.15 and 308.15) K from measurements of density and ultrasonic velocity. A qualitative interpretation of the results has been given using the Kirkwood model and nature of the interactions in solutions. A model, derived from Scaled Particle Theory, has been used for quantitative explanation of partial molar volumes and for the understanding the volumes of interaction. The results distinguish the behaviour of α-amino acids from that of α,ω-amino acids, and of the “less polar” 5-aminopentanoic acid from that of the analogous, but “more polar”, glycylglycine in solution. These findings are in agreement with previous studies in aqueous solutions and they support the water-structure making ability of sodium sulphate.     

Determination of calcium oxide in calcined phosphate ores

It has been shown that an existing procedure to differentiate calcium oxide from the carbonate and silicate of calcium can be used in the presence of the phosphate, fluoride and sulphate of calcium, and of the carbonate and oxide of magnesium. It is based on the reaction in aqueous solution of calcium oxide with sucrose to form calcium saccharate, and subsequent titration with oxalic acid solution. The method has application for a direct chemical determination of calcium oxide in phosphate rock where calcination of accompanying carbonate is necessary in beneficiation processes.     

Enantioselective Recognition for Carboxylic Acids by Novel Chiral Macrocyclic Polyamides Derived from L-/D-tartaric Acid

The enantioselectivity of chiral macrocyclic polyamides 1–3 derived from L-/D-tartaric acid was investigated by using ¹H NMR. All the macrocycles exhibited certain chiral recognition towards the enantiomers of the racemic carboxylic acids we had chosen. As a chiral solvating agent, the compound 3 has the excellent enantiomeric discriminating ability for mandelic acids and its derivatives, containing an α-OH at the chiral carbon, while the compound 2 has the best enantioselectivity towards dibenzoyltartaric acid. The molar ratio and the association constants of the compound 3 with each of the enantiomers of some guest molecules were determined by using the Job's plots and a nonlinear leastsquares fitting method, respectively. The effect of the structure of the hosts or guests on the enantioselectivity of the compound 1–3 has been explored.     

Chromatographic Studies of 34 Organic Acids on Papers Impregnated with Hydroxides of Aluminium and Cadmium

Abstract

Papers impregnated with aluminium hydroxide and cadmium hydroxide have been used for the chromatographic separation of organic acids exist in various biological materials, soil and water. The following important separations: cinnamic acid from hippuric acid; benzoic and m-nitrobenzoic acids from gallic, β-naphthalene acetic, β-naphthoxy acetic, phthalic, quinic and salicylic acids; and salicylic acid from citric, cis-aconitic, malic, quinic, tartaric and trans-aconitic acids can be achieved in common electrolytes (Cd(NO₃)₂, KI, NaCl, NH₄Cl) solution.

Hydroxides¹ show amphoteric behaviour i. e. they may exchange either cations or anions depending upon the pH of the solution, and t h i s may be shown by the following ionic equilibria.     

NICKEL(II) AND ZINC(II) COMPLEXES OF β-ALANINEHYDROXAMIC ACID

Abstract

Potentiometric and spectrophotometric studies of Ni(II) coordination to β-alaninehydroxamix acid (β-Alaha) have shown 4N coordination of β-Alaha for 1:2 species and their planar geometry. The geometry of the species formed in the nickel(II)-β-Alaha below ca. pH 7 is octahedral. The differences between the stabilities of zinc(II)-β-Alaha and zinc(II)-α-alaninehydroxamic acid complexes can be explained by the terdentate coordination of the β-alaninehydroxamic acid.     

Rate equation of the carbothermic reduction of zinc sulfide in the presence of calcium oxide and lithium carbonate

The kinetics of the carbothermic reduction of zinc sulfide in the presence of calcium oxide and lithium carbonate has been studied by a thermogravimetric analyzer (TGA). An empirical rate expression of zinc yield has been determined from the experimental data obtained. The dependencies of the rate of zinc yield on the operating variables was found to be less pronounced for the Li₂CO₃ catalyzed system than those for uncatalyzed system.     

Extraction - Spectrophotometric Determination of Phosphate Using N-Phenylbenzohydroxamic Acid

Abstract

A simple solvent extraction and spectrophotometric method for the determination of micro amount of phosphate (PO₄) is described. Phosphate is selectively separated from associated elements by reacting it with calcium and extracting excess calcium with N-phenylbenzohydroxamic acid (PBHA) at pH 11.3. The excess calcium was determined in ultra-violet and visible region and hence the phosphate content was calculated. The Beer's law is obeyed in the range 0.5 ? 10.0 ppm at 340 nm and 0.25 - 8.0 ppm at 560 nm of phosphate for a fixed amount of calcium (20.0 ppm). These results are also compared with those obtained by atomic absorption spectrophotometry. The method has been applied for the determination of phosphate in pharmaceutical and other samples.     

(Series Editor) Transform Techniques in Chemistry,P.R. Griffiths,D. Hercules (Eds.), in: Modern Analytical Chemistry Series,Plenum, New York,NY (1978), 385 pp. $47.40

Concentration potentials in zinc sulphate, copper sulphate, nickel sulphate and cobalt sulphate solutions across liquid membranes based on myristates and laurates of zinc, copper, nickel and cobalt and caprate and caprylate of copper have been studied in concentration cells in which the liquid membrane separates the two solutions of the same electrolyte. The behaviour of the cell with heavy metal soap liquid ion-exchange membranes becomes more and more nernstian as the number of carbon atoms in the hydrocarbon chain of the fatty acid soap increases. Concentration potential values with copper, zinc, nickel or cobalt soap follow the order of their insolubility in water. The failure to record the theoretical potentials as calculated by Nernst's equation has been explained by considering the transport of water across organic phase by hydrated ions and the dissolution of heavy metal soaps in aqueous solutions. Liquid membranes based on heavy metal myristate soaps when used in concentration cells could measure the activities of zinc, copper, nickel and cobalt ions in the concentration range of 10^?4–10^?1M.     

Zinc Ion Doped Solid-Phase Extraction of Eicosapentaenoic Acid and Docosahexaenoic Acid from Antarctic Krill

Antarctic krill crude extracts contain high levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Accordingly, the solid phase extraction of EPA and DHA from Antarctic krill crude extracts has attracted significant research interest. This study compared the extraction of EPA and DHA from Antarctic krill crude extracts using an aminopropyl, zinc ion-doped silica, and C₁₈ and zinc ion-doped C₁₈ solid-phase column. The best extraction effect was obtained using the zinc ion-doped C₁₈ SPE with water containing methanol as the eluant. The efficiency increased gradually with increasing methanol concentration from 12.5 to 25% in the washing stage, and when pure methanol (5.0 mL) or acetonitrile (3.0 mL) was used as the eluant. To detect EPA and DHA, the acids were first converted to their methyl esters and detected by gas chromatography with flame ionization detection (GC–FID). In the zinc ion-doped C₁₈ elution fractions, EPA and DHA were isolated from the crude extracts in high yield (85–91% (r² = 4.8–6.3%)).