I am currently trying to separate Domoic Acid in Mussel Tissue on a Zorbax SB-C8 column using a 1290 UHPLC and 6470 Triple Quad MS, the issue I am seeing as that the Domoic Acid is sitting in the column as no injections and MeOH solvent injections contain the peak in question for Domoic Acid.
I have run solvent (MeOH) multiple times as well as try and flush with mobile phase B for an hour as well as mobile phase A for an hour as well as flushing with pure MeOH and H2O with nothing working to remove Domoic Acid from the column. I have also tried conditioning/coating the column with Bovine Serum Albumin that has not worked either.
Am I correct in saying that because Domoic Acid is an Amino Acid the compound is binding with the stationary phase and/or possible sitting in the pores of the column via hydrophobic interaction between the compound and the stationary phase itself? The pore size of the column in question is 300 Angstrom, so would running with an 80 Angstrom pore size column alleviate the issue?
I'm not sure what else the issue might be other than the pore size based on the literature review and research I have conducted and any assistance would be greatly appreciated.
Kind regards, Rogan Van Kerpel