Paper Chromatographic Techniques

Both ascending and descending paper chromatographic techniques have been used and, when thin-layer supports are employed, the use of either silica gel or cellulose is applicable. As the number of carbohydrates present in the sample is often small, the careful choice of solvent will generally make it unnecessary to perform the two-dimensional separations that are often needed when large numbers of substances, such as amino acids, are present. Reference solutions of each carbohydrate can be made up in concentrations of approximately 2 g 1 1 dissolved in an isopropanol solvent (10% v/v in water) and samples of about 10 fx should give discernible spots after separation. 

A variety of other paper chromatographic techniques have also been described for the determination of cortisone acetate [127-129]. 

Comparative identification of a glycosyl ester of a nucleoside pyrophosphate with an authentic sample is usually based on the identity of their ultraviolet spectra and by comparison of chromatographic mobilities of the samples and their degradation products. In addition to paper-chromatographic techniques, it may be of value to use paper... 

Unfortunately, there are numerous ways to circumvent the analysis of total amino acids, such as by the addition of ammonium salts, inexpensive amino acids, peptides and protein hydrolysates. Several approaches have been made to verify the authenticity of the total amino acid values. Rockland and Underwood (10) developed a paper chromatographic technique for quantitatively estimating the individual amino acids. 

Allied with the chromatography of imidazoles have been methods of estimation of the compounds, particularly those of biological importance, either on the chromatograms or after elution. Most workers have used diazotized aromatic amines as colorimetric reagents,53,277-285 particularly nonsulfonated diazotized aniline derivatives.281-285 Mosebach et aZ.286 initially hydrolyzed. -substituted imidazoles with 10 A hydrochloric acid before separating the compounds by ion-exchange and paper chromatographic techniques prior to estimation. A number of other methods exist for the colori-... 

When paper chromatographic techniques designed for work on adult urine, such as those of Bush and Mahesh (B41), were applied to infant urine, considerable modifications were required mainly to deal with the increased amount of material which interfered both with chromatography and the specificity of color reactions (B18). Thin-layer silica-gel chromatography was found to be less susceptible to this interference, and with its use little preliminary purification is necessary (S9, SIO). 

Following the introduction of paper-chromatographic techniques, some fifteen years ago, there has been a steady change in the methods used for determining oligosaccharide structure. Many compounds are now only... 

They reported the presence of colchicine (208) and an unidentified alkaloid, mp 177-178°C, with a probable molecular formula, C33H38N2O9. Subsequent examination of the mature tubers of G. superba, which commonly cause poisoning in some rural areas of Sri Lanka (119,120), revealed colchicine (208) to be the major alkaloid (120). Colchicine was also found to occur in the tender tubers, seeds, and flowers. In addition to colchicine, mature tubers contained M-formyl-Al-desacetylcolchicine (209), 2-demethylcolchicine (210), lumicolchicine (211), and trace amounts of unidentified alkaloids (120). Seeds of Sri Lankan G. superba were also analyzed by Santavy and co-workers by paper chromatographic techniques and were shown to contain 208, 209, and 210 (121). A recent analytic and phytochemical study of G. superba cultivated in Sri Lanka for export revealed that the seeds contain the highest amounts of total alkaloids including colchicine (122). Alkaloids were also present in the tubers, leaves, and pericarp of this plant. 

B18). The mean levels of pyruvic acid in normal human whole blood found by most authors using paper chromatographic techniques are 0,35-0,92 mg% (M2). Specific enzymatic methods (H15, H23, SIO, S38) have given similar results by such a technique, Strohmeyer et al. (S38) found, for instance, 0.77 0,19 mg%. The same reasons as those discussed in the case of a-ketoglutaric acid explain why the most reliable data deal with whole blood and not plasma. 

It is not easily studied by paper chromatographic techniques because of its volatility and of its partial transformation into lactyllactic acid (Ol). 

D19. Durant, J. A., A one-dimensional paper chromatographic technique for the separation of phenols, phenolic acids and their derivatives. Nature 169, 1062 (1952). 

The results of recent isolation studies (through 1965) are summarized in Table I. A listing in this table implies that the substance in question has been either isolated and characterized or detected by standard paper chromatographic techniques. 

Benson (68), Benson, Miller, and Steim (69), Rakovic (739), Steim (907), and Steim and Benson (908,909) have reported on the extensive use of paper chromatographic techniques in their activation analysis experiments. Many of these investigations involved the pre-irradiation separation of the element of interest with the subsequent activation of the paper chromatogram. Smathers, Duffey, and Lakshmanan (865) and Nascutiu (640) have tested many different chromatographic papers for interfering nuclides by activation analysis. 

Isocyanate Identification by Colorimetric Test Diisocyanates can be identified by hydrolyzing the polyurethane and examining the breakdown products by infrared or paper chromatographic techniques. For a rapid qualitative check, however, a spot test is available. A small sample of polyurethane is heated in a test tube until white fumes are evolved and these fumes are absorbed on a filter paper. One drop of a solution of 4-nitrobenzene diazofluoroborate in methanol (approx. 1 %) on... 

T5 - S.N. Tewarl, "A New Paper Chromatographic Technique for the Detection and Identification of. Inorganic Ions",... 

Cartesio, M.S. and T.V. Campos. 1988. Malolactic fermentation in wine improvement in paper chromatographic techniques. Am.J. Enol. Vitic. 39 188-189. 

It must be noted that if the mixture of steroids to be separated contains both compounds B and S these two steroids are not resolved in this particular chromatographic system. The band containing compounds B and S is readily analyzed by paper chromatographic techniques. 

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