Thin-layer chromatography partition coefficients

The lipophilicity (7 m value) and specific hydrophobic surface area of pyrido[l,2-a]pyrazinium-l-olates 342 and -3-olate 343, and l-(4-chlorophe-nyl)-l-hydroxy-l,2-dihydropyrazino[2,l-a]isoquinolinium salt (344) has been measured by reversed-phase thin-layer chromatography (98MI13). Partition coefficient (log/ ) of 9-bromo-5-[(A-phenylaminocarbonyl)-methyl]-l,2,3,5,6,7-hexahydropyrido[l,2,3- fc]quinoxaline-2,3-dione was calculated to be 2.78 (97JMC4053). 

Palladium, D. of as dimethylglyoximate. (g) 463 as nioximate, (g) 474 by EDTA, (ti) 329 Paper chromatography 229 see Thin layer chromatography Parallax errors due to, 85 Parallel determinations 132 Partial ionic equations 850, (T) 851 Partition chromatography 13. 217 Partition coefficient 162 Patton and Reeder s indicator 317, 328 Peptisation 419. 421... 

The development and adaptation of procedures for the separation, isolation, purification, identification, and analysis of the components of the pyrethrum mixture have been studied and evaluated. Results of studies to determine the molar extinction coefficient of pyrethrin I as well as a gas chromatographic procedure for the determination of pyrethrins are reported. The use of chromatographic separation procedures (including partition, adsorption, gas, and thin-layer chromatography), colorimetry, and infrared spectrophotometry are discussed. 

Lipophilicity represents the affinity of a molecule or a moiety for a lipophilic environment. It is commonly measured by its distribution behavior in a biphasic system, either liquid-liquid (e.g. partition coefficient in 1-octanol-water) or solid-liquid (retention on reversed-phase high-performance liquid chromatography or thin-layer chromatography system). 

The logarithm of the 1 -octanol - water partition coefficient, denoted log Kq j or log P, indicates the distribution of the compound between the organic and the water phase. For highly lipophilic compounds, the log P is determined via reversed-phase thin-layer chromatography, giving the so-called log P tlc value1. 

Bruggeman, W. A., van der Steen, J., Hutzinger, O. (1982) Reversed-phase thin-layer chromatography of polynuclear aromatic hydrocarbons and chlorinated biphenyls. Relationship with hydrophobicity as measured by aqueous solubility and octanol-water partition coefficient. J. Chromatogr. 238, 335-346. 

Renberg, L.O., Sundstrom, S.G., and Rosen-Olofsson, A.-C. The determination of partition coefficients of organic compounds in technical products and waste waters for the estimation of their bioaccumulation potential using reversed phase thin layer chromatography, Toxicol. Environ. Chem., 10 333-349, 1985. 

Renberg, L., Sundstrom, G. (1979) Prediction of bioconcentration potential of organic compounds using partition coefficients derived from reversed phase thin layer chromatography. Chemosphere 7, 449 459. 

Armstrong and Nome " have shown that chromatographic methods such as high-pressure liquid chromatography (HPLC) and thin layer chromatography (TLC) can be used for determination of partition coefficients. The aqueous micellar solutions are used as the mobile phase. When the concentration of micelles in the mobile phase is increased, the retention and capacity factors of... 

Chromatographic parameters obtained from reversed-phase thin-layer chromatography are occasionally used as substitutes for partition coefficients [226 — 229]. Silica gel plates, being coated with hydrophobic phases (nowadays being commercially available), are eluated with aqueous/organic solvent systems of increasing water content. Eq. 26 converts the resulting R, values to R, values, which are true measures of lipophilicity. 

The first uses of micellar phases by Armstrong were done in GPC and thin layer chromatography (TLC). This was described in Chapter 3. TLCwas a useful tool for the determination of solute partition data in micellar systems. The micellar partition coefficient, Pv, the solute-stationary phase interaction coefficient, P s, and the micellar binding constant, Kd, could be obtained from the solute-Rf parameters with an equation very similar to eq. 13.5 [22]. A number of solutes were separated by micellar TLC such as phenols and dyes [22], indicators, caffeine, biphenyl, naphthol and benzamide [23], PAHs and amino acids [24], vitamins [25] or fluorescein derivatives [26]. The low cost, low toxicity, peculiar selectivity and ease of... 

Pliska, V. Schmidt, M. Fauchere, J.-L. Partition coefficients of amino acids and hydrophobic parameters of their side-chains as measured by thin-layer chromatography. J. Chromatogr. 1981, 216, 79. 

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