Coated and non-coated capillary - (Jul/22/2009 )
not sure if this has been asked before but I was reading around online searching for capillary electrophoresis and read an online book about using coated capillary tubes for CE.
Does anyone know the difference between using a coated and non coated capillary for CE? I've looked at company products regarding CE and not all of them stats if their capillary is coated or not.
Would be very grateful if someone can enlighten me on this as the university I work with does not have a CE machine.
capillaries are coated to neutralize the silicon. this negates eof (endo-osmotic force or flow). you do this so other separations can be performed (eg sds-ce, ief).
uncoated favors charge separations (eof runs from + to -, negatively charged molecules will be retarded by attraction to the - electrode).
so does this mean that I cannot use the non-coated capillary for DNA CE?
(slight error, it is electro-osmotic flow)
of course you can use a uncoated capillary. if necessary, there are additives that will neutralize eof. check the literature for the conditions for running dna.