Hyphenating columns and LCMS problems.

[jambon]

Will hyphenating a gaurd column to analytical column cause significant pressure for LCMS for electrospray ionisation. I know the baseline noise is likely increased.

Are there any resources for performance of hyphenated columns research either for HPLC / LCMS as I could not find any. Like calculation based evidence or evidence of such research using one mobile phase which should be one dimension (am I correct?) because true 2D method has 2 mobile phases applied for a RP and then for IEX separation for example.

So is the option of coupling a analytical column to C18 column more expensive than using just a mixed mode column in terms of purchase/ operating costs?.
I want to know more of your experiences in this area as I am thinking about it.

Thank You.

[Gerhard Kratz]

When you connect a guard column to an analytical column the back pressure will be slightly increased.
Foro the second part of your post please google publications from K.K. Unger and/or Pat Sandra.
These gentlemen are already retired. Try to use a C18 and than HILIC. If possible you will have one mobile phase for both columns. Good luck.