Help with PEG

[RocD]

I have done a biotin-streptavidin affinity pull down of my peptides which was pre-equlibrated in buffer with Triton-x-100 which was washed extensively before addition of peptides. There was a lot of Triton and PEG in the samples. The Triton I managed to get rid of using thermo made detergent removal columns. However, I am still stuck with the PEG.
is there a way to get rid of the PEG from my peptides so i can use them for ESI?

[proteaMatt]

A precipitation technique might be your best option for this problem (maybe acetone precipitation). I think there could be a case made for a SCX technique, but you might find that a standard SCX cleanup protocol would need to be modified.

[AAlpert]

Here's a couple of convenient cleanups with SPE cartridges:

1) SCX (per proteaMatt): Bind the peptides in something like 10 mM ammonium formate, pH 2.7, containing 20% ACN. Flush several times with the same solvent. Elute with 30% methanol containing 5% NH4OH.

2) HILIC: Add 4.5 vol. of ACN to your sample and bind to a HILIC SPE cartridge. Flush several times with 15 mm ammonium formate, pH 3.0, containing 85% ACN. Elute with 50 mM formic acid containing 10% ACN.

Either of these protocols will get rid of the Triton too, so you won't need the Thermo detergent removal column.