Paper chromatography reversed phase

In addition to actual partition coefficient measurements, there are a number of other descriptors in which the main property involved is a measure of hydrophobicity. Examples of these are various chromatographic measurements, such as thin layer, paper and reverse phase high performance liquid chromatography. Another interesting treatment is the decomposition of partition coefficients into enthalpic and entropic components, in an attempt to provide more mechanism-based parameters for hydrophobicity. 

Recently, Janjic et al. published some papers [33-36] on the influence of the stationary and mobile phase composition on the solvent strength parameter e° and SP, the system parameter (SP = log xjx, where and denote the mole fractions of the modiher in the stationary and the mobile phase, respectively) in normal phase and reversed-phase column chromatography. They established a linear dependence between SP and the Snyder s solvent strength parameters e° by performing experiments with binary solvent mixtures on silica and alumina layers. 

The correlation of Snyder s solvent strength e° with molecular dipolarity and polarizability (7t ) and the hydrogen-bond acidity (a) and the hydrogen-bond basicity ((3) solvatochromic parameters for adsorption chromatography can be achieved, although most papers on solvatochromic parameters deal with reversed-phase systems [18]. 

The problem of determining V-j in SEC is similar to that of determining zero retention time (tg) in other liquid chromatography columns. Recently, there have been several papers dealing with the determination of retention time of a retained peak in HPLC (12-19). In high-performance reversed-phase chromatography, McCormick and Karger (1 ) and Berendsen, et al., (16) have employed D2O to measure tg. Neidhart et al.,... 

Because polyphenolics show chemical complexities and similar structures, isolation and quantification of the individual polyphenolic compounds have been challenging. Many traditional techniques (paper chromatography, thin-layer chromatography, column chromatography) have been used. HPLC, with its merits of exacting resolution, ease of use, and short analysis time, has the further advantage that separation and quantification occur simultaneously. A reversed-phase HPLC apparatus equipped with a diode array detector makes possible the easy isolation and separation of many polyphenolics. For enhanced performance of HPLC separation, the polyphenolics should first be isolated into several fractions to effectively separate the individual polyphenolics (Jaworski and Lee, 1987 Oszmianski and Lee, 1990). 

T Hayashi, H Tsuchiya, H Naruse. Reversed-phase ion-pair chromatography of amino acids. Application to the determination of amino acids in plasma samples and dried blood on filter papers. J Chromatogr Biomed Appl 274 318-324, 1983. 

Reverse-phase liquid chromatography is now virtually the only method used in the analysis of the TG mixtures. The first paper on TG-HPLC analysis was published in 1975 by Pei et al. (81). Triglycerides were separated on a VYDAC reverse-phase (35 - 44 /xm) column and eluted with methanol-water (9 1). Since Pei et al. first applied RP-HPLC to the separation of triacyl-glycerols, a number of reverse-phase systems have been developed as rapid and efficient resolution of complex triacylglycerol mixtures can be achieved. 

Cerrai E, Ghersini G. 1966. Reversed-phase paper chromatography of some cations with two nitrophenylthiophosphate derivatives as stationary phases. J Chromatogr 22 425-430. 

Martin, H.R, Reversed phase paper chromatography and detection of steroids of the cholesterol class, Biochim. Biophys. Acta, 25, 408, 1957. 

Using the technique of electrophoresis on paper, Forfar et al. (F7) found that cholesterol was abnormally concentrated in the (3-lipoprotein fraction. Using reverse phase chromatography, an attempt was made to demonstrate sterols other than cholesterol, but this was unsuccessful. If they are actually present, such substances must have an Rf similar to that of cholesterol or else be present in quantities too small to be demonstrated by the technique employed. 

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