Re: What do eluting agents do for the process of chromatography

The type of chromatography that you refer to in your question is called 
solid phase extraction (SPE) or in older reference books, column 
chromatography.  The method consists of a plastic or glass column packed 
with sorbent (you can go to http://supelco.sial.com for a list of 
SPE 
sorbents.)  The packed tube is then conditioned with a buffered and pH 
specific solution to prepare the column to receive the sample.  An aqueous 
wash solution can be used to remove unwanted polar constituents (this also 
depends on the type of sorbent used for the SPE and the compound of 
interest.)  An eluting agent is finally used to remove the compound(s) of 
interest from the sorbent (these are usually solvents or a combination of 
solvents.)  The eluent can then be concentrated on a water bath with an N2 
stream, prior to analysis.  I hope this answers your question.  If you 
require additional assistance, you can contact me via E-mail at: 
dsherman@chr-hansen-us.com.