New column retention time

Hi,

I am currently verifying a method using an XSelect HSS C18 column 3.5micron, with a 99% aqueous mobile phase, and with a brand new column I am seeing retention times of double what is expected. I have sourced an older column from a colleague and when I use that the retention times are as expected. This column has not had significant usage. Is this a column equilibration issue? Should I prime the column with several injections of a high concentration of the analyte? Would this bring the retention time down and stabilise it?

Any advice is appreciated!

Answers

  • edited May 31
    Did you condition the column per manufacturers instructions before using it for the first time (check the column sheet, it's usually low flow, high organic)?

    How did you equilibrate the column before the analysis?

    Any mobile phase additives (ion pairing)?
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