ion suppression

[jiang295]

I know column separation can decrease ion suppression. but it is always better how can we fight for ion suppression in MS end.
is it diluted sample less prone to ion suppression than concentrated sample since both analyte and matrix can get ionization adequately in diluted sample.
please let me know if my thought is wrong.
besides that, which MS parameter can be optimized to decrease ion suppression, capillary voltage?

[Kostas Petritis]

More dilute samples will help as long as you can afford it from a MS sensitivity point of view...

[Ruth]

changing MS source may help...

[netsking]

I know column separation can decrease ion suppression. but it is always better how can we fight for ion suppression in MS end.
is it diluted sample less prone to ion suppression than concentrated sample since both analyte and matrix can get ionization adequately in diluted sample.
please let me know if my thought is wrong.
besides that, which MS parameter can be optimized to decrease ion suppression, capillary voltage?

Maybe collision energy

[analchem]

I'm not clear how collision energy can help a spray phenomenon such as suppression but I'm open to suggestion. APCI can certainly help significantly if sensitivity allows. I'm not aware of any other parameters MS-wise that can accomplish it. We have seen serious suppression on one MS platform that were much less on another. A cleaner extraction (to remove phospholipids, salts etc) can definitely improve things, along with dilution of course.

[mfiligenzi]

As far as we know, there's no really good way around ion suppression other than the use of isotopically labeled internal standards. We have several instruments from different manufacturers with different source designs in our lab and although they do vary in how they respond to different matrices, all give us problems with matrix suppression and/or enhancement.

Dilution can help as can matrix-matched standards but this remains the Achilles heel of ESI-LC/MS work.