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Paper chromatography is one method for testing the purity of compounds and identifying substances. Paper chromatography is a useful technique because it is relatively quick and requires only small quantities of material. Separations in paper chromatography involve the principle of partition.
In chromatography, the retardation factor (R) is the fraction of an analyte in the mobile phase of a chromatographic system. [1] In planar chromatography in particular, the retardation factor R F is defined as the ratio of the distance traveled by the center of a spot to the distance traveled by the solvent front. [2]
Planar chromatography is a separation technique in which the stationary phase is present as or on a plane. The plane can be a paper, serving as such or impregnated by a substance as the stationary bed (paper chromatography) or a layer of solid particles spread on a support such as a glass plate (thin-layer chromatography).
The distribution constant (or partition ratio) (K D) is the equilibrium constant for the distribution of an analyte in two immiscible solvents. [1] [2] [3]In chromatography, for a particular solvent, it is equal to the ratio of its molar concentration in the stationary phase to its molar concentration in the mobile phase, also approximating the ratio of the solubility of the solvent in each phase.
Chromatographic peak resolution is given by = + where t R is the retention time and w b is the peak width at baseline. The bigger the time-difference and/or the smaller the bandwidths, the better the resolution of the compounds.
Ninhydrin (2,2-dihydroxyindane-1,3-dione) is an organic compound with the formula C 6 H 4 (CO) 2 C(OH) 2.It is used to detect ammonia and amines.Upon reaction with these amines, ninhydrin gets converted into deep blue or purple derivatives, which are called Ruhemann's purple.
In liquid chromatography, the mobile phase velocity is taken as the exit velocity, that is, the ratio of the flow rate in ml/second to the cross-sectional area of the ‘column-exit flow path.’ For a packed column, the cross-sectional area of the column exit flow path is usually taken as 0.6 times the cross-sectional area of the column.
Thin-layer chromatography (TLC) is a chromatography technique that separates components in non-volatile mixtures. [ 1 ] It is performed on a TLC plate made up of a non-reactive solid coated with a thin layer of adsorbent material. [ 2 ]