Chromatography Of Dyes Research Articles

Lake Pigments and Thin-Layer Chromatography of Natural Dyes: Paired Experiments for Nonmajors

Lake Pigments and Thin-Layer Chromatography of Natural Dyes: Paired Experiments for Nonmajors

Extração e purificação de clorofila a, da alga Spirulina maxima: um experimento para os cursos de química

This work describes a simple and economical experiment for the extraction and purification of chlorophyll a from Spirulina maxima. Extraction and purification of natural compounds can be considered one of the most illustrative experiments that can be performed in Organic Chemistry courses. Particularly, the chromatography of dyes and pigments allows students to have a better comprehension of the chromatography separations. These compounds represent an important class of organic pigments applied in pharmaceutical, cosmetic, detergent compositions, and various other fields and can be extracted from plants and algae. To extract, separate and purify chlorophyll a from associated pigments such as xanthophylls, carotenes, and pheophytins, very costly processes are reported. The present approach is perfectly adequate for use in Chemistry experiments for undergraduate students.

Chemistry of the surface and structural and adsorption properties of fluorinated carbon fiber and an adsorbent based on it

The chemistry of the surface and structural and adsorption properties of fluorinated carbon fiber were studied by IR spectroscopy, gas chromatography, and static adsorption of vapors and dyes from aqueous solutions. Also, the quantitative characteristics of the influence of a binder (polytetrafluoroethylene) used to prepare a granulated adsorbent on the basis of the fiber were determined. The functional properties of the adsorbent were found to be largely determined by the properties of the initial fluorocarbon fiber. Fluorocarbons were shown to possess a developed porous structure and highly hydrophobic chemically homogeneous nonpolar surface for the adsorption of most of the organic compounds studied.

Azeotropic mixtures as mobile phase for thin-layer chromatography of organic fluorescent dyes

Reproducible R f values in the thin-layer chromatography (TLC) of various fluorescent dyes (amino derivatives of naphthoylenebenzimidazole, naphthalimide, benzanthrone, phenalenone, including phosphorus-containing luminophores) were shown to be obtained by elution with binary homogeneous azeotropic mixtures of solvents of different polarity. Some trends in the chromatographic mobility were established governed by the structural features of the groups of compounds under study.

Chromatography of synthetic dyes on mixed sorbent layers

Thin layer chromatography of synthetic dyes has been performed on mixed sorbent layers containing silica gel G, calcium sulfate and barium sulfate separately in ethanol + water (80 : 20) solvent system. The separation potential of admixtures has been explored systematically. Several important separations of closely related synthetic dyes have been achieved.

Microchannel Thin Layer Chromatography with in situ Plate Scanning Micro-DRIFTS Detection Using Plain and Polybutadiene Modified Zirconia Stationary Phases

Thin layer chromatography (TLC) of various dyes is compared in microchannels packed with either bare zirconia (normal phase) or polybutadiene (PBD) modified zirconia (reversed phase). In situ micro-diffuse reflectance infrared Fourier transform spectroscopy (μDRIFTS) of the analyte spots is possible due to the low absorption background of both plain and PBD zirconia. An instrument coupling μDRIFTS with a motorized stage that could profile the microchannel TLC plate is developed. The retention order of anthracene and pyrene probes as a function of percent acetonitrile are generally as expected on PBD zirconia but opposite for plain zirconia. Impurities in technical grade methylene blue can be determined after TLC separation on plain zirconia. The separation and infrared identification of various dyes such as dichlorofluorescein and rhodamine B on PBD zirconia is improved using a mobile phase with an additive such as phosphate or dihexylamine that prevents band streaking.

Plain and ion-pair thin-layer chromatography of synthetic dyes on an admixture of silica gel G and barium sulfate in an aqueous ethanol system.

An easy, inexpensive, and accurate method for the analysis of synthetic dyes by means of ion-pair thin-layer chromatography (IPTLC) on mixed sorbent phases containing silica gel G and barium sulfate in an aqueous ethanol system is studied. The effect of the composition of the sorbent phases has a major effect on the hundred-fold relative migration rate, as also does the effect of the ion-pairing reagent as the impregnant. Compact and sharp spot application yields very good binary and ternary separations and enables their clear identification. IPTLC has better separations on mixed sorbent phases, which are not possible on plain mixed phases in thin-layer chromatography. The method can be applied for the trace analysis of synthetic dyes in various natural and synthetic samples.

Chromatography of Food Dyes: A Simple Demonstration for Actively Engaging High School Students in the Chemistry of Foods

ABSTRACT: A simple demonstration of the chromatography of food dyes suitable for high school students is presented. Reversed phase mini‐columns are utilized to separate dyes in grape and lime drinks. The exercise introduces chromatography and reinforces the concept of polarity. It has been successfully used to actively engage students for periods of 30 to 60 min.

Chromatography of Food Dyes: A Simple Demonstration for Actively Engaging High School Students in the Chemistry of Foods

Chromatography of Food Dyes: A Simple Demonstration for Actively Engaging High School Students in the Chemistry of Foods

Column Chromatography of Dyes: Microanalysis with a Thin Layer Chromatography Scanner Works to Beat the Bands

Quantitative analysis students have performed the following experiment in our laboratories for 15 yr with generally disappointing results: column chromatographic separation of a dye mixture on alumina followed by spectrophotometric analysis of the eluates and quantification of the dyes using Beer's law. Previous workers claimed that these dyes, Victoria Blue R, methylene blue, and fluorescein, are separable under the chromatography conditions, but we have always had loss of dye on the column or poor separation or both. We have formulated a replacement dye mixture (Oil Red O, Victoria Blue R, fluorescein) that separates cleanly with inexpensive solvents. For preliminary studies we used TLC plates with novel sample application discs and a TLC scanner to measure λ maxvalues for microgram quantities of the dyes. The dyes mentioned can be recovered nearly quantitatively from alumina columns. The mud-colored dye mixture becomes aesthetically pleasing as the dyes move down the column and separate into brightly colored bands, making this experiment useful for classroom demonstrations of the column chromatographic technique.

Thin-layer chromatography of laser dyes and dye analogs with cyclodextrins in the mobile phase

The addition of β-cyclodextrin and substituted hydroxyethyl and hydroxypropyl-β-cyclodextrins to aqueous urea-containing mobile phases, can be used to enhance the migration of various laser dyes on thin layer chromatography. Selected laser dyes from the coumarin, rhodamine and bimane families were examined, as well as a number of dye analogs. Silica gel, polyamide and C18 reverse phase plates were utilized. Overall, the substituted hydroxypropyl-β-cyclodextrins appeared to be the most effective for increasing dye migration.

High‐performance liquid chromatography of blue and purple indigoid natural dyes

Four major components of blue and purple natural dyes of the Indigoid class were separated and spectrally characterised by high‐performance liquid chromatography: indigotin, indirubin, 6‐monobromoindigotin and 6,6′‐dibromoindigotin. It has been shown for the first time that a dyeing with a hypobranchial glandular secretion of Murex trunculus L contains indigotin and both its mono‐and di‐substituted brominated derivative. The analytical features presented may be used to study the composition of old dyes on yarns.

Thin Layer Chromatography of Synthetic Dyes on Antimonic Acid and on Admixture of Antimonic Acid and Silica Gel ‘G’ in a Mixed Solvent System

Abstract Thin layer chromatography of synthetic dyes have been performed on antimonic acid and on admixture of antimonic acid and silica gel ‘G’ in a mixed solvent system i. e. Butanol: Acetic acid: water (25:5:10). The separation potential of antimonic acid and silica gel ‘G’ has been explored. Several important separations of closely related dyes have been achieved as a result of such studies.

Thin layer chromatography of azoic dyes extracted from cotton fibres

A thin layer chromatography system has been produced for the examination of azoic dyes extracted from single cotton fibres. Dyes of this class are successfully analysed by using ethyl acetate for initial sharpening of dye spots followed by separation in a mixture of chlorobenzene, 1,2-dichloroethane and acetone (20: 20: 1).

High-performance liquid chromatography of acidic dyes on a dynamically modified polystyrene-divinylbenzene packing material with multi-wavelength detection and absorbance ratio characterisation

A chromatographic system utilising a dynamically modified 5-µm polystyrene-divinylbenzene packing material for the analysis of acidic dyes under isocratic conditions is described. When used in conjunction with a multi-wavelength UV-visible diode array detector an absorbance ratio technique (absorbance ratioing) provided a method for the characterisation of the 52 acidic dyes chromatographed under these conditions.

The ideal solvent for paper chromatography of food dyes

The author points out that while the solvents normally used in paper chromatography are not particularly hazardous or expensive, they are not always practical or available for high school laboratories. He suggests the substitution of a salt solution and describes the preparation of such a solution as well as its superiority to normal solvents.

Thin Layer Chromatography of Azine and Oxazine Dyes

Thin Layer Chromatography of Azine and Oxazine Dyes

High-performance liquid affinity chromatography on silica-bound alcohol dehydrogenase

Horse liver alcohol dehydrogenase was immobilized on glycerylpropyl-silica (10 μm, 1000-Å pores) activated with 2,2,2-trifluoroethanesulfonyl chloride (tresyl chloride). The coupling and activity yield was almost 100%. The coenzyme-binding sites were equivalent and virtually unaffected by the immobilization process, as judged from Scatchard plots and active-site titrations. The silica-bound enzyme, packed in steel columns, was integrated with HPLC equipment and then successfully used for chromatography of adenine nucleosides, adenine nucleotides, and triazine dyes. Dissociation constants were calculated from chromatographic data and found to correspond well with literature values. The dissociation constants for a number of nucleotide derivatives with potential application in affinity chromatography were also determined. The spacers were found to affect the binding strength of the nucleotides in a qualitatively predictable way. Theoretical plate heights were calculated and found to be in the range 0.01 to 0.1 cm. Attempts to correlate peak widths with the rate constants for the binary complexes involved were only partially successful.

遠心式液体クロマトグラフによる色素のクロマトグラフィーと溶離液の挙動

遠心式液体クロマトグラフによる色素のクロマトグラフィーと溶離液の挙動

Exclusion chromatography of anionic dyes : Anomalous elution peaks due to reversible aggregation

Several anionic dyes, especially the barbiturate and pyrazolone oxonol dyes, were shown by exclusion chromatography to form large, monodisperse, polymeric aggregates in dimethylformamide. Their size was approximately that of polystyrene of molecular weight 10 6 daltons. They were in labile equilibrium with monomer and dissociated in salt solution. The anomalous elution profile with a threshold characteristic of the dye and a peak increasingly retarded with increasing dye quantity was explained in terms of continuing concentration-dependent monomer-aggregate equilibrium during chromatography. This aggregation was contrasted with the association in water which accompanies a change in optical absorption spectrum and gives smaller particles. A vesicular structure of membrane made of associated dye molecules, with an electrical double layer was suggested on the basis of the monodisperse large size of the aggregates, their instability in salt solution and the ionic nature of the dyes. Exclusion chromatography allows the study of aggregation phenomena which cannot be followed by measurements of colligative properties or absorption spectra.