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الأهميه لكروماتوغرافي السائل ترجع إلى ان بعض المواد ليست بطياره كفاية بحيث تستطيع فصلها بكروماتوغرافي الغاز
وتتطلب درجات الفصل العاليه اتزانات مكتمله للمذابات بين الاطوار لهذا يستخدم جسيمات دعم صلبه صغيره جدا وطبقات رقيقه من الطور السائل وحشوه مترابطه لتلك الجسيمات واقطار اعمده صغيره ايضا.
الجسيمات المذكوره اعلاه تعطي درجات فصل افضل بسبب:
#‏ السريان المتجانس خلال العمود.
#‏ المسافه التي ينتشر من خلالها المذاب في الطور المتحرك في مستوى الجسيمات.
#‏ معدل السريان الأفضل والذي يكون اسرع بالنسبه للجسيمات الصغيره بسبب انتشار المذاب خلال مسافات اصغر,وكذلك يفضل استخدام ضغط عالي حيث يؤدي استخدام ضغط قدره 1000-ps7000 الى انتاج معدل سريان0.5- كروماتوغرافيا 51018210

5ml/min

Paper chromatography is an analytical technique for separating and identifying mixtures that are or can be coloured, especially pigments. This can also be used in secondary or primary schools in ink experiments. This method has been largely replaced by thin layer chromatography, however it is still a powerful teaching tool. Two-way paper chromatography, also called two-dimensional chromatography, involves using two solvents and rotating the paper 90° in between. This is useful for separating complex mixtures of similar compounds, for example, amino acids.
Technique

A small concentrated spot of solution that contains the sample of the solute is applied to a strip of chromatography paper about 2 cm away from the base of the plate, usually using a capillary tube for maximum precision. This sample is absorbed onto the paper and may form interactions with it. Any substance that reacts or bonds with the paper cannot be measured using this technique. The paper is then dipped in to a suitable solvent, such as ethanol or water, taking care that the spot is above the surface of the solvent, and placed in a sealed container. The solvent moves up the paper by capillary action, which occurs as a result of the attraction of the solvent molecules to the paper,also this can be explained as differential absorption of the solute components into the solvent. As the solvent rises through the paper it meets and dissolves the sample mixture, which will then travel up the paper with the solvent solute sample. Different compounds in the sample mixture travel at different rates due to differences in solubility in the solvent, and due to differences in their attraction to the fibers in the paper. Paper chromatography takes anywhere from several minutes to several hours. In some cases, paper chromatography does not separate pigments completely; this occurs when two substances appear to have the same values in a particular solvent. In these cases, two-way chromatography is used to separate the multiple-pigment spots.

Column chromatography
Column chromatography is a separation technique in which the stationary bed is within a tube. The particles of the solid stationary phase or the support coated with a liquid stationary phase may fill the whole inside volume of the tube (packed column) or be concentrated on or along the inside tube wall leaving an open, unrestricted path for the mobile phase in the middle part of the tube (open tubular column). Differences in rates of movement through the medium are calculated to different retention times of the sample.^[1]
In 1978, W. C. Still introduced a modified version of column chromatography called flash column chromatography (flash).^[2] The technique is very similar to the traditional column chromatography, except for that the solvent is driven through the column by applying positive pressure. This allowed most separations to be performed in less than 20 minutes, with improved separations compared to the old method. Modern flash chromatography systems are sold as pre-packed plastic cartridges, and the solvent is pumped through the cartridge. Systems may also be linked with detectors and fraction collectors providing automation. The introduction of gradient pumps resulted in quicker separations and less solvent usage.
In expanded bed adsorption, a fluidized bed is used, rather than a solid phase made by a packed bed. This allows omission of initial clearing steps such as centrifugation and filtration, for culture broths or slurries of broken cells.
Planar Chromatography

Thin layer chromatography is used to separate components of chlorophyll
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). Different compounds in the sample mixture travel different distances according to how strongly they interact with the stationary phase as compared to the mobile phase . The specific Retardation factor (R_f) of each chemical can be used to aid in the identification of an unknown substance.
Paper Chromatography
For more details on this topic, see Paper chromatography.
Paper chromatography is a technique that involves placing a small dot of sample solution onto a strip of chromatography paper. The paper is placed in a jar containing a shallow layer of solvent and sealed. As the solvent rises through the paper it meets the sample mixture which starts to travel up the paper with the solvent. This paper is made of cellulose, a polar substance, and the compounds within the mixture travel farther if they are non-polar. More polar substances bond with the cellulose paper more quickly, and therefore do not travel as far.
[edit] Thin layer chromatography
For more details on this topic, see Thin layer chromatography.
Thin layer chromatography (TLC) is a widely-employed laboratory technique and is similar to paper chromatography. However, instead of using a stationary phase of paper, it involves a stationary phase of a thin layer of adsorbent like silica gel, alumina, or cellulose on a flat, inert substrate. Compared to paper, it has the advantage of faster runs, better separations, and the choice between different adsorbents. For even better resolution and to allow for quantitation, high-performance TLC can be used.

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