Negative ion calibration

[MIB_EO]

Anybody got any suggestions as to what to use to create a calibration curve in Negative Ion ESI TOF MS.

I normally use PEG for positive ion, and haven't had to work in Neg before. PEG however doesn't ionise in Neg ion mode.

If it makes a dfference I'm running a Waters LCT.

[BillW]

I assume that you mean calibration of the mass axis. In that case, I would recomend Agilent's TOF calibration mix. It works in both + and - ion mode and is pre-mixed. Ingredients are in the product insert, so you could make it up yourself if u like.