Thin two-dimensional layer

The total phosphoms content of the sample is determined by method AOCS Ja 5-55. Analysis of phosphoUpid in lecithin concentrates (AOCS Ja 7-86) is performed by fractionation with two-dimensional thin-layer chromatography (tic) followed by acid digestion and reaction with molybdate to measure total phosphorous for each fraction at 310 nm. It is a semiquantitative method for PC, PE, PI, PA, LPC, and LPE. Method AOCS Ja 7b-91 is for the direct deterrnination of single phosphoHpids PE, PA, PI, PC in lecithin by high performance Hquid chromatography (hplc). The method is appHcable to oil-containing lecithins, deoiled lecithins, lecithin fractions, but not appHcable to lyso-PC and lyso-PE. 

G. Guiochon, M. F. Gonnord, A. M. Siouffi and M. Zakaria, Study of the performances of tliin-layer cltromatography. VII. Spot capacity in two-dimensional thin-layer cltromatography , 7. Chromatogr. 250 1 -20 (1982). 

Two-dimensional thin-layer chromatography. This method is used to verify the presence of terminal 5-sultones, terminal unsaturated y-sultone, and terminal 2-chloro-y-sultone, if they are detected in the gas chromatographic determination. After extraction of the neutral oil from the AOS sample, the neutral oil is made up volumetrically to at least a 10% solution in hexane. Of this solution 3 pi is spotted onto a silica gel TLC plate together with standard sultones. It is twice developed with 2-propyl ether and then after turning the plate 90° twice developed with 60/40 n-butyl chloride/methylene chloride. The... 

Successive separation steps, e.g. in two-dimensional chromatography (two-dimensional thin-layer chromatography) that result in three-dimensional signal functions y = f(ziyz2)y as schematically shown in Fig. 3.4(v). 

The theoretical work that exploited the advantages of the multidimensional separation format appears to have been developed much later than the original experimental work. One of the earliest studies was conducted by Connors (1974), who assumed that the distribution of spots on a two-dimensional thin-layer chromatography (2DTLC) plate could be modeled using a Poisson distribution of data on each retention axis. He then constructed equations that related the number of chromatographic systems needed to resolve a specific number of compounds. One... 

This effect is illustrated in Fig. 17.1. Multidimensional chromatography separations can be done in planar systems or coupled-column systems. Examples of planar systems include two-dimensional thin-layer chromatography (TLC) (Consden et al., 1944 Grinberg et al., 1990), where successive one-dimensional TLC experiments are performed at 90° angles with different solvents, and 2D electrophoresis, where gel electrophoresis is run in the first dimension followed by isoelectric focusing in the second dimension (O Farrell, 1975 Anderson et al., 1981 Celis and... 

Two-dimensional thin-layer chromatography (TLC) with adsorbent gradient has allowed the separation of quinolizidine alkaloids in the herb and in several alkaloids from Genista sp. <2004MI89>. 

Figure 28.3 Two-Dimensional Thin-Layer Chromatogram of some Amino-Acids A = Sample spot Solvent-1 Toluene 2-Chlorocthanol Pyridine Solvent - 2 Chloroform Benzylalc Acetic Acid...

Special attention was given to the characterization of the radioactive metabolites found in the strawberry fruits where no parent compound was detectable. Unidentified, very polar metabolites accounted for 83% of the material while 3% was identified as thiazolidine-2-thione-4-carboxylic acid by two-dimensional thin-layer chromatography. Treatment with diazomethane allowed for GC-MS confirmation of the latter as the methylated derivatives of the thiazolidine. 

Two-dimensional, thin-layer chromatography can also be used for... 

Tentative confirmation of suspected liquid chromatographic peaks has been achieved in the analysis of carazolol and seven sedatives in swine kidney, by using photodiode-array detection in the wavelengUi range of 220-320 nm. It was reported (526) that further identification could be made possible if the corresponding fractions of the eluate were submitted off-line to two-dimensional thin-layer chromatography. 

Speccropho tome trie detn of HNDPhA in micro gram quantities) 7) S.K. Yasuda, Explosivst 1963 ( 2), 34- 38 CA 60, 14325(1964) (Identification N Nitroso N-Nitrodiphenylamines by two-dimensional thin-layer chromatography)... 

Figure 3-5 Photograph of a two-dimensional thin layer (silica gel) chromatogram of a mixture of flavins formed by irradiation of 10 pg of the vitamin riboflavin. The photograph was made by the fluorescence of the compounds under ultraviolet light. Some riboflavin (RF) remains. The arrows indicate the location of the sample spot before chromatography. Chromatography solvents a mixture of acetic acid, 2-hutanone, methanol, and benzene in one direction and M-butanol, acetic acid, and water in the other. See Treadwell et al.H)2...

Friedberg and Hayden (15) reported that glutamic acid was formed when poly-L-proline was irradiated in dilute aqueous solution in the absence of 02. We also found glutamic acid formation (G = 0.14) under similar conditions and confirmed the identity of the glutamic acid by two-dimensional thin-layer chromatography. A possible intermediate in this reaction... 

Two-dimensional chromatography. When complex mixtures are to be studied, the Rf values of the individual components may be so close that a clear-cut separation of the components is not achieved. In such a case a two-dimensional thin-layer chromatographic separation can be used with advantage. 

This problem was approached by incorporating radioactive percur-sors into the glycolipids of both brain and lymphoma cells of the Thy-1.2 and 1.1 types. We have used C-palmitate as a per-cursor of ceramide, and - C-N-acetylmannosamine as a percursor of sialic acid (7). Glycolipids were isolated and the radioactive gangliosides were resolved by two-dimensional thin layer chromatography in two different solvent systems followed by autoradiography. 

W. Markowski and K. L. Czapinska, Computer simulation of the separation in one- and two-dimensional thin-layer chromatography by isocratic and stepwise gradient development , J. Liq. Chromatogr. 18 1405-1427 (1995). 

M. Zakaria, M. F. Gonnord and G. Guiochon, Applications of two-dimensional thin-layer chromatography , J. Chromatogr. 271 127-192(1983). 

Prinzler, H.W., Tauchmann, H., and Tzcharnke, C., Thin-layer chromatographic separation of organic sulfoxides and dinitrothioethers some observations on reproducibility and structural influence. II. Separation of sulfoxide mixtures by one- and two-dimensional thin layer chromatography, J. Chromatogr., 29, 151, 1967 Chem Abs., 67, 96615m, 1967. 

Hodgson, E., Smith, E., and Guthrie, F.E., Two-dimensional thin-layer chromatography of tobacco alkaloids and related compounds, J. Chromatogr., 20, 176, 1965 Chem. Abs., 64, 3960b, 1966. 

S. Habibi-Goudarzi, K. J. Ruterbories, J. E. Steinbrunner, and D. Nurok, A computer-aided survey of systems for separating steroids by two-dimensional thin-layer chromatography, J PC, 7 161 (1988). 

Deleu et al. [26] have used two-dimensional thin layer chromatography and gas chromatography to separate and identify 10 urea herbicides in concentrations down to 4pg L 1 in river waters (Fig. 14.1). Four different adsorbents were compared. The eluting solutions were ... 

Saxena et al. [512] used polyurethane foams to concentrate trace quantities of six representatives of polynuclear aromatic hydrocarbons (fluoranthene, benzo(k)fluoranthene, benzo(j)fluoranthene, benzo(a) pyrene, benzo(ghi) perylene, and indeno(l,2,3-cd)pyrene) prior to regular screening of these compounds in US raw and potable waters. Final purification and resolution of samples was by gas chromatography and two-dimensional thin layer chromatography, followed by fluorometric analysis and quantification. 

Figure 8. Two-dimensional thin-layer chromatographic separation of fenithrothion and possible breakdown products (spots (I) fenitrothion (2) fenitrooxon (3) aminofenitrothion (4) 3-melhyl-4-nitrophenol (361...

Jee, M.H. and Ritchie, A.S. (1984) Two-dimensional thin-layer chromatography technique for use in lipid analysis. Journal of Chromatogr., 299, 460-464. 

The use of two-dimensional thin-layer chromatography for separation of platelet lipids will provide the profile exhibited in Figure 3-3. 

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