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.     

Separation and Identification of Certain Organophosphorous Pesticides Residues in Vegetable

Abstract

A rapid and sensitive method using impregnated thin layer chromatography (TLC) for detection and estimation of organophosphorous pesticides residues from vegetable has been developed. Compared to ordinary thin layer chromatography this method is faster more sensitive and accurate. The correlation with the Impregnant (p-cresol) and the pesticides have been determined by Infrared Spectroscopy.     

Thin Layer Chromatographic and “In Situ” Spectrophotometric Determination of Products in Solid-Solid Thermal Reaction

Abstract

A method coupling thin layer chromatography and direct spectrophotometry is outlined. The visible spectra of the separated species were obtained by scanning, at constant intervals of wavelenght, the chromatographic plates in the reflectance mode. The method is applied to the determination of unknown products obtained in thermal solid-solid reactions between [Co(bipy)₂(en)]Cl₃ and NH₄Cl.     

Synthetic Inorganic Ion Exchangers. XIV Thin-Layer Chromatography of Metal Ions on Thorium Phosphate: Quantitative Separation of Au (III) from Several Metal Ions

Abstract

The analytical potential of thorium phosphate as an ion exchanger has been explored by thin layer chromatographic (TLC) technique. Binder-free thin layers of thorium phos -phate have been explored for several important binary and ternary separations. A TLC method has been developed for quantitative separation of microgram-quantities of Au(III) from several metal ions in pure butanol system.     

Evaluation of various biological activities of natural compounds by TLC/HPTLC

Abstract

Over the last years, thin layer chromatography (TLC) has become an increasingly important tool in the analysis of natural compounds, being used not only as a simple method of separation, identification, and quantitative determination of natural constituents, but also as a method for evaluating the potential applications of the separated compounds, different bioassays being compatible with TLC. This is due to the TLC advantages, of which could be mentioned: the possibility to simply, quickly, and flexibly analyze many samples in parallel, without the need for special steps of sample purification, obtaining visual results, and the possibility of multiple detections, all of these being achieved at very low costs. Considering these, the aim of this study is to give an overview on the application of TLC in evaluation of different biological activities of natural compounds, focusing on antioxidant, enzymatic, antimicrobial, and hormonal activities.     

Determination of Aminacrine Hydro-Chloride in Drug Preparations by TLC with Fluorescence Densitometry

Abstract

A densitometric TLC method was developed for quantification of aminacrine hydrochloride in creams, jellies, and suppositories. Aminacrine was extracted into acidic ethanol, diluted to a known volume, and separated by high performance silica gel TLC. The fluorescence of aminacrine zones in samples and standards was compared by in situ scanning. Recoveries of aminacrine from authentic samples ranged from 95.4 to 103.4%.     

Use of High Pressure Liquid Chromatography and Thin Layer Chromatography for the Separation and Detection of Testosterone and its Metabolites from in vitro Incubation Mixtures

Abstract

Testosterone and its 6β-, 7α-, and 16α-hydroxylated metabolites were resolved by high pressure liquid chromatography and thin layer chromatography. Separation by HPLC was achieved in less than 45 min on a microparticulate silica gel column using isocratic elution with isopro-panol:tetrahydrofuran:hexane (5:15:80) as the mobile phase. TLC systems utilizing silica gel on glass and plastic plates, and polysilicic acid on glass fiber sheets are presented. The monohydroxylated metabolites of testosterone formed during incubation of (¹⁴C)-testosterone with liver postmitochondrial preparations from adult male rats pre-treated with phenobarbital or Aroclor 1254 were separated and quantitated by both HPLC and TLC. The results using both techniques are compared with those obtained by paper chromatography.     

Determination of Biphenyl in Citrus Fruits by Quantitative Thin-Layer Chromatography

Abstract

Residues of the fungicide biphenyl in citrus fruits have been determined by direct scanning of spots on phosphor-impregnated high performance silica gel TLC plates under UV light. Biphenyl was separated from fruit tissue by steam liquid-liquid extraction. Recoveries from spiked samples ranged from 92–99% at 100, 50, and 10 ppm levels. The precision of the TLC determination and overall procedure are shown to be adequate for residue analysis.     

Thin Layer Chromatographic Method for Rapid Identification and Quantification of Corticosteroid Sodium Phosphates in Pharmaceutical Preparations

Abstract

A rapid and inexpensive thin layer chromatography (TLC) procedure for the assay of dexamethasone sodium phosphate (DSP) and betamethasone sodium phosphate (BSP) persent in pharmaceutical preparations is described. Free steroids liberated after alkaline phosphatase reaction is isolated by TLC on silica gel layer and estimated after elution with ethanol. Assay of unesterified steroids and identification of the preservatives like methyl or propyl parabenzoates, phenol, benzyl alcohol etc. may also be carried out by this method without any additional cost. Possibility of using this method for other corticosteroid sodium phosphates (CSP) are discussed.     

An Improved Copper Reagent for Quantitative Densitometric Thin-Layer Chromatography of Lipids

Abstract

Eleven cupric compounds were screened to determine whether a different cupric anion might give greater and more uniform charring responses with lipid classes on TLC plates than cupric acetate. A procedure was developed which used 10% CuSO₄ in 8% H₃PO₄ as a charring reagent. Improved reproducibility of charring was obtained by temperature-programmed heating of the thin layer plates from 30 to 180°C at 10 degrees per minute in the oven of a commercial gas-liquid chromatograph.     

Two-Wavelength Spectrophotometric Determination of Organic and Inorganic Mercury in Ultra Micro Amounts on Thin Layer Chromatography (I)

Abstract

This report describes the initial approach of a method for two-wavelength spectrophotometric determination of trace amounts of organic and inorganic mercuric compounds separated on a plate of thin layer chromatograph. Using this two-wavelength spectrophotometry, several organic and inorganic mercuric compounds being separated on the plate of thin layer chromatograph can be measured without racking spots.     

Separation Studies of Metal Ions in Sodium Thioglycolate Medium by Thin Layer Partition Chromatography

Abstract

A thin layer partition chromatographic method has been developed for separation of Fe(III), Ni(II), Zn(II), Cu(II), Pb(II) and Mn(II) on thin layers of silica gel-G as an adsorbent. The R_f values were determined using 0.01–0.2 aqueous solution of sodium thioglycolate as a mobile phase. The dependence of R_f values on the migration time, pH and concentration of mobile phase has been studied. The optimum conditions for possible 3-component separation have been determined. Metal ions have been separated, detected, eluted and quantitatively determined by atomic absorption spectroscopy. The present method was applied to the separation and determination of zinc in forensic samples.     

Class Fractionation of Acidic Glycolipids and Further Separation of Gangliosides by OPTLC

Abstract

The use of the OPTLC method has been extended to the separation of the acidic fraction of the total lipid extract derived from a given blood element. This newly developed method is suitable for the interclass separation of sulphatides and gangliosides and further intraclass separation of gangliosides on the same TLC plate with step gradient development. The elutions can be performed on 10 × 10 cm (or larger) HPTLC plates with 13 parallels on each one. The chromatograms were stained either with orcinol-H₂SO₄ to show class separation (in this case only a single isocratic elution was performed) or with rescrcinol-HCl reagent to visualize the ganglioside intraclass separation. The chromatograms were evaluated by spectrodensitometric scanning and the reproducibility of the separation was determined.     

On-Plate Electrochemical Detection for Thin-Layer Chromatography

Abstract

Voltammetric electrochemical detection (ECD) coupled with thin-layer chromatography (TLC) was demonstrated for the quantification of trace organic compounds directly on a TLC plate. the electrochemical detection solvent was a thin layer of aqueous potassium chloride. For undeveloped plates, detection limits for p-anisidine and p-phenetidine were 10 ng and 13 ng, respectively. Linearity was demonstrated over nearly 2 orders of magnitude. After development, detection limits increased by approximately a factor of ten. Advantages of this method over other quantitative TLC methods include sensitivity, speed, simplicity, and cost. in addition, this method is selective for electrochemically active compounds. Major sources of experimental error include spot size reproducibility, working electrode placement, and supporting electrolyte film thickness.     

Determination of Allantoin in Drug Preparations by Quantitative High Performance TLC

Abstract

A densitometric TLC method was developed for the quantification of allantoin in creams and suppositories used to treat vaginal infections. Allantoin was extracted with water at elevated temperature, diluted to a known volume, and separated by HP silica gel TLC. Allantoin was detected by spraying with p-dimethylamine-benzaldehyde reagent. The absorption of standards and samples was compared by in situ scanning. Recoveries of allantoin from authentic samples ranged from 96–102%, except for one sample that assayed high. The accuracy of the method was demonstrated by standard addition analysis of this sample.     

Quantitative Analysis of a Chloroquinolin-Ethenyl Phenyl Derivative Using Thin Layers Impregnated With Di-P-Toluyl Tartaricacid

Abstract

Thin Layer Chromatography (TLC) is an established method for the evaluation of final product drug and intermediate impurity profiles. Quantitative TLC has gained credibility within the Pharmaceutical industry as a result of the latest developments in an availability of scanning technology. In the present paper we wish to report a quantitative TLC method for the determination of some potential impurities which may exist in a final bulk drug MK0679. In order to improve the selectivity of the chromatographic method, di-p-toluyl tartaric acid was impregnated on the stationary phase. Utilizing the modified layer, complete separation of the known impurity was obtained. The calibration curves for all components studied were linear and the detection limits obtained were less than 5ng.     

Study of Segregation Effects and Fusion Between Lipid Vesicles by Combined Scanning Dilatometric and Calorimetric Measurements

Abstract

Scanning dilatometric and calorimetric measurements were performed in order to obtain information on correlations between various phenomena involving a lipid vesicle. Scanning dilatometry has been shown to be a fast and reliable tool which gives complementary information to that obtained using differential scanning calorimetry and also, provides a means with which to follow dynamic processes without the introduction of perturbing probes into the lipid matrix. The systems examined were vesicles built up from mixtures of neutral and charged lipids in the presence of mono- and divalent inorganic cations. The studied processes were the gel-liquid crystal transition, lateral phase separation in mixed lipid vesicles and fusion between vesicles.     

Normal Phase TLC Separation of Enantiomers Using Chiral Ion Interaction Agents

Abstract

A method for the thin layer chromatographic (TLC) separation of enantiomers and diastereomers involving the use of chiral ion interaction agents is described. Several aromatic amino alcohols were resolved by TLC on diol and/or high performance silica gel plates using a mobile phase containing (1R)-(-)- ammonium-10-camphorsulfonate or N-benzoxycarbonyl-glycyl-L-proline (ZGP). Many of these chiral aromatic amino alcohols are of pharmacological importance as α- and β-adrenergic blockers, adrenergic compounds, and anti-glaucoma agents. A comparison was made between various N-CBZ-amino acid derivatives as chiral counter ions/chiral mobile phase additives (CMAs). These separations could not be achieved on other normal phase TLC stationary phases including microcrystalline cellulose, alumina and ordinary silica gel plates.     

Analysis of PCB's by Thin-Layer Chromatography

Abstract

A screening thin layer chromatography (TLC) technique has been developed that can be done in the field. Quantitative analysis by TLC densitometry can be done in a laboratory (or field van). A densitometer is needed for quantitative work by TLC. An Apple computer may be added to use as a computational device. Semi-quantitative results may be obtained by visual comparisons. Confirmations may be made by silver halide visualization on TLC. Dehalogenation with sodium biphenyl, chlorination with antimony pentachloride, or mass spectral confirmation may be used. Quantitative analysis is possible of the derivatized positive samples.     

Thin Layer Chromatographic Separation of Ortho,Meta, and Para Substituted Benzoic Acids and Phenols with Aqueous Solutions of α-Cyclodextrin

Abstract

The use of aqueous solutions of α-cyclodextrin as the mobile phase in thin layer chromatography (TLC) is described. A series of eighteen substituted benzoic acid compounds were chromatographed on polyamide thin layer sheets. The R_f values were dependent on the concentration of α-cyclodextrin in the mobile phase as well as the structure and size of the individual molecules. Possible advantages of this technique over those which use pure or mixed solvent systems as the mobile phase are discussed.