By Anonymous on Wednesday, June 23, 2004 - 08:37 am:

I've developed a procedure to separate seven cyclic and aromatic amines on a LUNA SCX ion exchange column using a mobile phase of 90% 20mM KH2PO4 at pH 2.4 and 10%ACN. There are 6 compounds in all and separation of 2 of them is ultra pH dependant. If I change the pH by 0.1 upwards or downwards I loose resolution. Does this fail the robustness check? Also is there anything I can do to improve matters? Th3e compound which 'suffers' most from pH change is pyrimidine (like pyridine except its got 2 Ns )
Best regards
Hendrik

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By Anonymous on Thursday, June 24, 2004 - 10:51 pm:

Use e.g. nitric acid plus ACN