soma
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Changing composition of eluent mixture during liquid chromatography
I'm looking for information on changing the composition of the eluent mix during a liquid chromatography separation.
My understanding is that you slowly change the ratio of solvents towards the more polar starting after the end of one front?
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unionised
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Does this help?
http://www.chromedia.org/chromedia?waxtrapp=mxrorDsHqnOxmOlI...
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soma
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Thanks.
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Metacelsus
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Note that for a silica column, changing directly from a very nonpolar (example: 2% ethyl acetate in hexanes) to a much more polar eluent (example: 50%
ethyl acetate in hexanes) can disrupt the column and cause cracking and uneven flow. I'm not completely sure why this happens, and sometimes I can get
away with doing it, but I think it's because heat is released and the temperature increase causes thermal expansion. When I need to change polarity
over a large range I try to do it gradually.
[Edited on 10-28-2017 by Metacelsus]
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