Chromatography, affinity high pressure liquid

In this review we examine improvements in column techniques, development of new separation media, and new applications of interest to the clinical chemist and biochemist. As a consequence of the wide nature of column chromatography, we have necessarily had to limit ourselves to fields where most progress has been made over the last few years. Thus we have confined ourselves mainly to affinity chromatography, gel chromatography, and high pressure liquid chromatography. 

The methods of RNA isolation depends on the tissue and type of RNA to be extracted. Procedures to isolate total cellular RNA include chemical extractions and centrifugation. mRNA is isolated from total RNA using affinity chromatography or magnetic beads, while high-pressure liquid chromatography methods are used for small RNA molecules. Phenol extraction was one of the first techniques to isolate RNA successfully from many sources... 

J Selhub. Determination of tissue folate composition by affinity chromatography followed by high-pressure ion pair liquid chromatography. Anal Biochem 182 84-93,1989. 

Several analytical and separation techniques are based on the reversible formation of complexes between alkenes and Ag+ ions. Analytical methods for terpenes, unsaturated acids and esters, and other unsaturated nonpolar compounds are based on the use of Ag" -impregnated materials for thin-layer (TLC) and high-pressure (HPLC) as well as gas-liquid (GLC) chromatography. GLC measurements done some years ago suggest that the affinity decreases with additional substituents, but increases with strain. ... 

High-performance liquid chromatography (HPLC). HPLC is a chromatographic method that separates compounds from other compounds through differences in molecular size or affinity to a stationary phase. In the HPLC system, a sample solution passes though a column with a mobile phase at high pressure and separated compounds are monitored by a detector. HPLC has advantages in selectivity and sensitivity, and is thus widely used for determination of small molecules. 

Ion-exchange chromatography involves an electrostatic process which depends on the relative affinities of various types of ions for an immobilised assembly of ions of opposite charge. The stationary phase is an aqueous buffer with a fixed pH or an aqueous mixture of buffers in which the pH is continuously increased or decreased as the separation may require. This form of liquid chromatography can also be performed at high inlet pressures of liquid with increased column performances. 

This chapter focuses on gas-liquid chromatography, in which compounds in a sample are separated based on vapor pressures and differences in affinity for the stationary phase (a high boiling point liquid) versus the gaseous mobile phase. The time between sample injection and detection of the individual compound eluting from the column is called the retention time. Compounds that have limited solubility in the stationary phase will exit the column quickly as a large proportion will remain in the mobile phase. Compounds with polarity similar to that of the stationary phase will have longer retention times and potentially broader peaks, due to increased interaction with the stationary phase. 

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