ghost peak in GPC

[push]

Hi,
I use anhydrous 1,2,4-trichlorobenzene in our high temperature GPC (120C), using BHT as an added antioxidant. I have noticed that the fresh solvent does not reveal any ghost peak, but after 6-7 injections of a blank sample (TCB+BHT) a ghost peak rises in LALS and RALS signals in low molecular weight region.
What can cause this peak?

[Gerhard Kratz]

How long is one run? Maybe this is a temperature problem. Are you sure that your mobile phase is at the same temperature than the column in the oven when entering the column?

[tom jupille]

The various oxidation products of BHT ?

http://195.37.231.82/publications/pac/p ... 0x1615.pdf