Thin-layer chromatography anionics

Nonionic surfactants, including EO-PO block copolymers, may be readily separated from anionic surfactants by a simple batch ion exchange method [21] analytical separation of EO-PO copolymers from other nonionic surfactants is possible by thin-layer chromatography (TLC) [22,23] and paper chromatography [24], and EO-PO copolymers may themselves be separated into narrow molecular weight fractions on a preparative scale by gel permeation chromatography (GPC) [25]. 

Thin-layer chromatography (TLC) is used both for characterization of alcohol sulfates and alcohol ether sulfates and for their analysis in mixtures. This technique, combined with the use of scanning densitometers, is a quantitative analytical method. TLC is preferred to HPLC in this case as anionic surfactants do not contain strong chromophores and the refractive index detector is of low sensitivity and not suitable for gradient elution. A recent development in HPLC detector technology, the evaporative light-scattering detector, will probably overcome these sensitivity problems. 

Takitani, S. and Kawanabe, K., Thin-layer chromatography of inorganic ions (anions), Kagaku No Ryoiki Zokan, 64, 221, 1964. 

Chapter 14 discusses the very useful technique of thin layer chromatography. It has extensive applications in the analysis of complex mixtures of organic compounds and also has found limited applications in the analysis of organometallic compounds. No applications to anions and cations have been reported to date. The technique can also be used to prepare extracts suitable for subsequent examination by infrared spectroscopy or mass spectrometry. 

VI.18 SEPARATIONS BY PAPER AND THIN LAYER CHROMATOGRAPHY. GENERAL INTRODUCTION Separations of certain cations (including some of the rarer elements, discussed in Chapter VII) and anions can be carried out effectively by either paper or thin layer chromatography or both. 

Graham, R. J. T., Bark, L. S., Tinsley, D. A. Quantitative thin-layer chromatography on liquid anion exchangers Part I. An investigation into some of the parameters involved in the direct densitometric determination of zinc. J. Chromatogr. 39, 211 (1969)... 

Several functional groups have been used to obtain cellulose anion exchangers [aminoethyl (AE), diethyl-aminoethyl (DEAE)], or cation exchangers [car-boxymethyl (CM), phosphate (P)] for thin-layer chromatography. PEI cellulose is not a chemically modified cellulose, but a complex of cellulose with polyethyleneimine. These cellulose exchangers are particularly useful for the separation of proteins, aminoacids, enzymes, nucleobases, nucleosides, nucleotides, and nucleic acids. 

For the separation of anionic analytes, the positively charged macrocyclic antibiotic vancomycin is one of the most commonly used chiral selectors. It was introduced by Armstrong and coworkers as a new class of chiral selector in CE, HPLC and thin-layer chromatography for the separation of a wide range of enantiomers [29, 47-52]. It contains multiple stereogenic centers and a variety of functional groups. 

Size exclusion chromatography, p. 620 Ion exchange chromatography—cation, anion, p. 622 Ion chromatography—suppressor columns, p. 625 Thin-layer chromatography—2-D, high performance, p. 627 Electrophoresis, p. 631... 

Deleted. Three experiments that use mercury have been deleted. The paper chromatography experiment is deleted because thin-layer chromatography is predominantly used in its place today. For space reasons, the presentation of catalytic methods and the corresponding experirnent are deleted from the text in favor of enzymatic kinetic methods. Also, the anion chromatography separation of cobalt and nickel is omitted. 

IR spectroscopy is used for the qualitative identihcation of surfactants and for differentiating between them and nonsurfactant compounds. Prior to IR spectroscopy, however, separation of the organic compound complex into different fractions, performed by, e.g., the use of thin-layer chromatography, is required to obtain meaningful spectra. °" ° By comparing the IR spectra of the isolated fractions with IR spectra of standard compounds with regard to characteristic bands, the qualitative determination of surfactants in environmental samples is possible. The method is equally applicable to anionic, ° nonionic, °" and cationic surfactants.The prerequisite for a clear identification of surfactants, however, is the availability of suitable standards. Moreover, considerable experience and knowledge are needed to interpret IR spectra of environmental samples. 

Medium basic anion ex- % change column and thin layer chromatography... 

Thin Layer Chromatography. - Complex mixtures of phosphorus-32 postlabelled DNA adducts have been analysed by high-resolution anion-exchange and partition thin-layer chromatography. ... 

The method for separation of nucleotides on DEAE-paper disks is simple to operate compared with anion-exchange or thin-layer chromatography, and a large number of samples can be handled simultaneously. 

The nucleotide profiles of Figs. 1-1 and 1-2 show that cells and tissues contain complex mixtures of nucleotides. The principal components of such mixtures can be isolated and determined using current methods of column and thin-layer chromatography with anion exchange media. However, a crucial step prior to analysis is the extraction of nucleotides from cells. With some tissues, the extraction procedure has a profound influence on the analytical result and special precautions must be taken if the result is to truly represent the nucleotide composition of living cells. 

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