Buffer Concentration of the Eluent

The behavior ofthe anion exchanger is exactly the opposite. If the pH values are higher, SAX and WAX have a shorter retention. 

Instead of a salt concentration gradient, a pH gradient can also be used. In this case, eluting conditions are if the pH value moves toward the samples pi value -there is no more retention at the pi value - or, as explained above, the charge number on the exchanger is reduced. 

This variant can be applied for LC-MS, because this avoids large quantities of salt, which would significantly reduce the sensitivity of the analytic of peptides 

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