The Zero Flow™ CE capillary is made from a bare fused silica capillary but has an inner coating which is covalently bonded with linear polyacrylamide (LPA). Since it does not have any ionizable groups it is considered “effectively neutral” and has not charge. Therefore noticeable EOF is not observed when using this capillary even when current is applied across the field of this capillary.
This should not be confused with polyimide, which is a coating on the outer surface of all CE capillaries. This outer coating imparts structural integrity and rigidity to the capillary, which would break easily without it.
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