Quantitative Separation of Citric Acid From Trichloroacetic Acid on Plates Coated with Calcium Sulphate Containing Zinc Oxide

Abstract

Thin-layer chromatographic behaviour of ten acids on coating of calcium sulphate containing ammonium molybdate, aluminium oxide, calcium carbonate, copper sulphate, ferric chloride, magnesium sulphate, phthalic anhydride, titanium oxide, zinc oxide etc. has been studied. Quantitative separation of citric acid from trichloroacetic acids has been achieved on calcium sulphate containirig zinc oxide in ethyl acetate. Herbicide, trichloroacetic acid can be separated from plant growth regulators such as indole-3-acetic, β-naphthaleneacetic and β-naphthoxy acetic acids and from other organic acids.     

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.     

Effective Separation of Bacterial Phospholipids and Neutral Lipids in one Dimensional Thin Layer Chromatography

Abstract

A method for effective separation of phospholipids and neutral lipids of E. Coli in one dimensional thin layer chromatography on ready-made plates has been proposed. The chromatographing was made successively in three different solvent systems. About ten lipid components were shown to be separated on the same plate.     

Reversed Phase Thin Layer Chromatography of Amino Acids

Abstract

The use of reversed phase layers for the thin layer chromatography of amino acids is described. Only when a modifier was added to the mobile phase was clear separation of the amino acids achieved. Ion paring with trifluoroacetic acid overcame problems with streaking and poor separation on C₂ or C₁₈ reversed phase layers. All amino acids could not be separated with a single mobile phase. Thus, three different combination of acetonitrile-0.4% trifluoroacetic acid were used to separate eighteen amino acids with derivatization. No derivative was required.     

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.     

Chromatographic Separation on Silica of Polar Aromatic Compounds II) Research of the Best Chromatographic System by Different Preloading in Thin Layer for a Transposition on Column

Abstract

A high performance thin layer chromatographic method for aromatic compounds separation with absorbant deactivation has been given in the precedent work. Our aim was to transpose the results obtain from HPTLC to HPLC. The two types of results were then related by a transposition coefficient, K_tR which interprets the geometrical variations of the two chromatographic methods. The values obtained for K_tR represent fairly well the linear relation between the retentions in thin layer chromatography and those in column chromatography. We have thus desmontrated the possibility of modifying adsorbent activity in the same manner in thin layer as in column chromatography by the fixation of chemical compounds, thus allowing the separation of relatively polar compounds.     

Thin-Layer Chromatographic Separation of Copper and Mercury Chelates

Abstract

Thin-layer chromatographic separation of metal ions has become immensely popular in analytical chemistry in view of its speed, selectivity and applicability at tracer level. Quinoline-2-aldehyde thiosemicarbazone^1,2 was found to form yellow coloured chelates with metal ions such as copper, nickel, zinc, mercury, iron and lead at pH 7.5 and extract into chloroform. This, however reduces the sensitivity of the reagent as a chromogenic agent but the chromatographic run of the chelates on a thin layer of silica gel coated on glass plate increases the specificity and selectivity of the reagent. In this article we propose a method for separation of copper and mercury chelates from binary mixtures containing chelates of zinc, lead, iron and nickel. The method is applicable for analysis of synthetic mixtures and standard samples.     

Separation and Analysis of Nucleic Acids and Their Constituents by Ion-Exclusion and Ion-Exchange Column Chromatography

The recent commercial development of high pressure liquid chromatographic instruments, and the availability of small and uniformly sized resin beads has enhanced the role of column chromatography for the rapid assay of nucleic acid components. A major advancement in the purification and analysis has been due to the recent demonstration that the ion exclusion is more or equally effective than the ion exchange as a separation principle for the resolution of purine and pyrimidine bases, nucleosides, deoxynucleosides and nucleotides^1–3. This article deals with the recent applications of separation principles that have been employed for the separation of nucleic acid constituents. The reader is referred to two review articles of Cohn for the earlier works on this subject^{4, 5}. Separations by chromatography and electrophoresis on paper and thin layers are not described here; several monographs and review articles are available in the literature^6–12.The reader is also referred to a recent methodological study for the base analysis of ribopolynucleotides by chemical tritium labeling which utilizes two dimensional chromatography on thin layers of cellulose as a separation means^{13, 14}.     

Micropreparative TLC Separation of Large Sample Volumes. Frontal + Elution Chromatography

Abstract

It is demonstrated that mixtures containing few compounds can be applied as wide zones on the edge of the thin layer using a sandwich tank with glass distributor. The mixture is partially separated during application (frontal chromatography) so that subsequent elution accomplishes complete separation. Using 5 × 20 cm plates of silica, 0.5 mm thick, 1 - 3 ml samples were separated easily which permitted elution of 3 - 9 of separated compounds from a single plate.     

Chemiluminescence Detection of Amino Acids,Peptides, and Proteins Using Tris-2,2′-Bipyridine Ruthenium (III)

Abstract

The feasibility of using the tris-2-2′-bipyridine ruthenium (III) (Ru(bpy)₃ ^{3 +}) chemiluminescent (CL) reaction for the detection of amino acids, peptides, and proteins has been studied.

Detection limits of the amino acids as determined by flow injection analysis (FIA) ranged from 20 pmol of proline to 50 nmol of asparagine. In general, amino acids containing secondary amine groups yielded the strongest responses. A reaction mechanism for Ru (bpy)₃ ^{3 +} chemiluminescence of aliphatic amines has been proposed. Studies of peptide molecules and poly-prolines showed that the peptide bond barely contributes to the detection signals. The separation of hydroxyproline and proline in synthetic collagen by HPLC with Ru (bpy)₃ ^{3 +} chemiluminescence detection has been shown to be possible.     

SEPARATION OF SOME AROMATIC CARBONYL COMPOUNDS BY THIN LAYER CHROMATOGRAPHY OF THEIR ISONICOTINOYL HYDRAZONE DERIVATIVES

Abstract

The separation of 13 isonicotinoyl hydrazones derived from some isomeric aromatic carbonyl compounds by thin layer chromatography is described. Methods for separating and identifying the components of complex mixtures of these hydrazones are discussed.     

Thin Layer Chromatography of Some Metals on Silica Gel Layers Impregnated with Phenolic Acids

Abstract

Thin layer chromatography of metals was performed on silica gel impregnated with phenolic acids. The results obtained can be used to gain a better insight into the behaviour of metals under the proposed chromatographic conditions and as an additional system for their separation.     

Determination of Some Bipyridylium Herbicides by Ring-Oven Techniques

Abstract

The development of a rapid and a simple “Weisz ring-oven” method is described for the semiquantative determination of diquat and paraquat. In this method column chromatography is used for the separation of herbicides from water and soil samples. Further evidence of the identity of individual residues is provided by thin layer chromatography.     

Synthesis of Functionalized Thiodisaccharides by Conjugate Addition

Abstract

Oligosaccharides containing thioglycosidic linkages are resistant to enzyme-catalysed hydrolysis and therefore interesting material for studies of carbohydrate hydrolases. Some of these were shown to be competitive inhibitors for several glycanases such as α-amylase,¹ cellobiohydrolase I and II,² and for α-l-fucosidase,³ a glycosidase. Thio-oligosaccharides have also been used to prepare column material for affinity chromatography to isolate carbohydrate hydrolases. In contrast, affinity material containing normal O-glycosidic bonds was hydrolysed and led to column deterioration. By employing this approach, affinity materials containing 1,4-dithiocellobiose and 1,4,4′-trithiocellotriose could be used successfully to separate the cellobiohydrolases of Trichoderma reesei.²     

A benzothiazole-based receptor-immobilised silica nanoparticle as chemosensor for Hg2+

Fluorogenic benzothiazole-based receptor has been easily immobilised onto filter paper and silica nanoparticle by sol-gel reaction. The sensing ability of the benzothiazole-immobilised thin layer filter paper chromatography (TLC-1) was evaluated on the basis of fluorescent changes caused by metal ions that were dropped onto the TLC plate. The TLC-1 exhibited a high affinity and selectivity for Hg²⁺ over other competing metal ions. Therefore, the TLC-1 holds promise as a portable sensor for the detection of Hg²⁺ in aqueous solution. Furthermore, the adsorption capacity of a column packed with SiO₂-1 was evaluated by the application of metal ions under various experimental conditions, such as pH, flow rate and concentration. The SiO2-1 column removed 98% of Hg²⁺ from drinking water containing 10 ppb of Hg²⁺. The adsorption capacity of the SiO₂-1 column was not strongly affected by pH and flow rates.     

Quantitative Densitometry in Situ of Lipids Separated by thin Layer Chromatography

Abstract

Operating parameters are described for a densitometric method to determine in situ eight lipid classes separated by thin layer chromatography. The separated lipids, visualized on the TLC plate by a cupric acetate-phosphoric acid charring method, were quantitatively determined by spectrodensitometry using the Shimadzu CS-910 Dual Wavelength TLC Scanner. Plates were scanned in either a linear scanning mode or in a zigzag scanning mode (flying spot).

Reproducibility of a) sample application (spotting) and b) the lipid separation procedure was determined by scanning. Transmittance measurements yielded response areas that were 2.8 X higher than reflectance measurements. Operating parameters such as scanning direction, wavelength, single and dual-wavelength measurement, scanning speed, and slit geometry were studied. Optimal conditions were established for quantitative densitometry of lipids on thin layer plates.     

The Behaviour of Some Phenolic Acids and Aldehydes on Thin Layers of Silica Gel Impregnated with Fe(III)

Abstract

The behaviour of phenolic aldehydes and acids commonly found in lacustrine sediments as degradation products of lignine was tested by thin layer chromatography on silica gel plates plain and impregnated with Fe(III) in different solvent systems. The differences expressed as R_i values can be used as one of the parameters in the identification of some phenolic aldehydes or acids.     

Separation of radioarsenic from irradiated germanium oxide targets for the production of <Superscript>71</Superscript>As and <Superscript>72</Superscript>As

A method for the separation of no-carrier-added arsenic radionuclides from the bulk amount of proton-irradiated GeO₂ targets as well as from coproduced radiogallium was developed. The radionuclides ⁶⁹Ge and ⁶⁷Ga produced during irradiation of GeO₂ were used as tracers for Ge and Ga in the experiments. After dissolution of the target the ratio of As(III) to As(V) was determined via thin layer chromatography (TLC). The extraction of radioarsenic by different organic solvents from acid solutions containing alkali iodide was studied and optimized. The influence of the concentration of various acids (HCl, HClO₄, HNO₃, HBr, H₂SO₄) as well as of KI was studied using cyclohexane. The optimum separation of radioarsenic was achieved using cyclohexane with 4.75 M HCl and 0.5 M KI and its back-extraction with a 0.1% H₂O₂ solution. The separation leads to high purity radioarsenic containing no radiogallium and <0.001% [⁶⁹Ge]Ge. The overall radiochemical yield is 93 ± 3%. The practical application of the optimized procedure in the production of ⁷¹As and ⁷²As is demonstrated and batch yields achieved were in the range of 75–84% of the theoretical values.     

Determination of90Sr by thin layer radiochromatography

A simple method for the determination of⁹⁰Sr by using thin layer chromatography on silica gel or cellulose pretreated with calcium oxalate is proposed. In these conditions a complete separation between strontium and its daughter yttrium is obtained. Radioactivity of separated elements was measured by a linear multiscanner analyzer and the results were computer processed to obtain the activity of⁹⁰Sr. The method has been applied to samples of water and milk subjected to a very simple extraction procedure. Under the experimental conditions used, the detection limit is about 25 mBq of deposited radioactivity, which corresponds to about 6 Bq/l.     

Modifications of Adsorbent,Sample and Solvent in Thin Layer Chromatography

Abstract

This review covers, from a practical point of view, the modifications of the sample, adsorbent and solvent, which are available to achieve the separation of complex chemical mixtures by thin layer chromatography.