Column chromatography technique

High Pressure Liquid Chromatography. This modem version of the classical column chromatography technique is also used successfully for separation and quantitative analysis of dyes. It is generally faster than thin-layer or paper chromatography however, it requires considerably more expensive equipment. Visible and uv photometers or spectrophotometers are used to quantify the amounts of substances present. 

Purified extracts contain higher contents of tea catechins obtained by further purification processes, for example solvent extraction or column chromatography techniques (Takeo, 2001). New techniques, such as membrane extraction and separation, may be beneficial in producing such extracts (Nwuha, 2000, Wang et al, 1995). 

The column chromatography technique using Dowex 50 ion-exchange resin, introduced in 1951 (M2) and improved in 1954 (M3) by Moore and Stein, first made possible the precise quantitative analysis of amino acids liberated in the course of acid hydrolysis of urine. Similar results were also obtained by Muting in 1954 (M4), who used paper chromatography methods. In this procedure amino acids were quantitatively determined after staining on the paper and elution of the resulting spots. 

Hydrophobic interaction chromatography (HIC) is a column chromatography technique which can determine particle hydrophobicity by interaction with a hydrophobic gel matrix [142,149,150]. Hydrophilic particles pass through the column without interaction, whereas particles with increased hydrophobicity show a retarded elution and are retained by the column. Hydrophobicity measurements are used to determine the hydrophobicity of nanoparticulate carriers and correlate this to their in vivo biodistribution [10, 149]. 

Chromatography on an alumina micro column [67] and a Florisil column [134] can be used to separate PCDEs from PCDFs. PCBs are also separated from PCDDs and PCDFs on Florisil and alumina [111, 112]. Group separation on these materials can be achieved by using sequential elution with solvents of increasing polarity. Florisil column chromatography technique has been used in mostPCDE studies [33,57,58,113,114,120,123-126,128,130,131] and alumina chromatography less [120]. Fractionation has also been performed on silica gel [51,119] and carbon [116,131,132]. 

Bulk matrix removal by liquid-solid chromatography has been performed on Florisil, silica, modified silica gel, and modified celite [51,108,115,116,121,126, 128, 132]. Silica gel (activated) [51] and the Florisil column chromatography technique [108,121,126,128] have been used to remove lipids from fish muscle, bird eggs and tissues (muscle, liver, fat), and rat tissues (muscle, liver, blood, skin) and for bulk matrix removal of sediment extracts. Extracts have been elut-... 

For any worker studying a biochemical system, there exist the fundamental problems of first isolating and examining the individual components of a system before consideration of that system as a whole. To a large extent, the rapid advances made in the bio-sciences during the last two decades can be attributed to improved separation techniques. Column chromatography techniques have played a valuable part in these advances. 

The above chemical separations work on the basis of forming diastereomeric pairs as intermediates the same principle applies to the column chromatography techniques that have been developed over the past few years, in which a chiral metal complex is attached to the stationary phase. A number of complexes based on Cu", Ni", Zn" and Co " have been shown to be capable of resolving amino acids. A reverse-phase technique has also been described in which Cu" or Zn" peptide complexes are used in the mobile rather than the stationary phase. ... 

Pipettes The Pasteur pipette is shown in Figure 5.5A with a 2-mL rubber bulb attached. There are two sizes of pipettes a long one (9 inch) and a short one (5% inch). It is important that the pipette bulb fit securely. You should not use a medicine dropper bulb, because of its small capacity. A Pasteur pipette is an indispensable piece of equipment for the routine transfer of liquids. It is also used for separations (Technique 12). Pasteur pipettes may be packed with cotton for use in gravity filtration (Technique 8) or packed with an adsorbent for small-scale column chromatography (Technique 19). Although they are considered disposable, you should be able to clean them for reuse as long as the tip remains unchipped. 

Size-Exclusion Chromatography n (SEC, gel-permeation chromatography) A column-chromatography technique... 

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