Different GPC columns in series - Ghost peaks and peak splitting


We recently installed a second column on our GPC to get a better resolution in the low Mw range. We currently have Agilent PL1110-6500​ PLgel MIXED-C (200-2.000.000 Da) and Agilent PL1113-6520 OligoPore (100-3.300 Da) in series. After installation we noticed several ghost peaks on all our samples, overlapping with the PS-M EasiVial calibration samples (162-364.000 Da). We only saw 1 ghost peak before. We already replaced the solvent bottle with a new one (THF) but without success. Where could these peaks originate from and how could we solve this?

Secondly we observed some peak splitting for the higher MW samples. Is there anything we can do to circumvent this issue?



  • When looking to combine GPC columns in series, it is important to consider the columns that you are using.  Typically with MIXED columns, we do recommend using columns only of the same type together; ex MIXED C with MIXED C.   Putting other columns in series could result in a 'mismatch' of sorts.  What I might first suggest to do would be to remove the Oligopore and rerun the standards and sample.  Do the ghost peaks go away?  Do the shoulders on the high MW standards go away?   Some of what you might be seeing could be due to possibly a mismatch of the Oligopore on the MIXED C or maybe the connection to the second column is incorrect?   If you have further questions, I might suggest to email to the columns group at lc-column-support@agilent.com.

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