Topic
Retention time
Page 6 of 15 — Why retention time is a hint and not a fingerprint, and what co-elution can hide behind a beautiful single peak.
Messages — page 6 of 15
salt_bridgeupdate on the earlier thing does retention time on its own tell you what the compound is#hplc-massspec · 2025-09-16salt_bridgedo you trust an area percent from a shallow gradient#hplc-massspec · 2025-09-16ten_percent_offthe retention time on this one is different from the last lot, problem#coa-reading · 2025-09-20endotoxin_edretention time shifts between runs are normal. relative retention time is the number to compare#coa-reading · 2025-09-20fibre_firstright so the retention time on this one is different from the last lot, problem#coa-reading · 2025-09-23lot_number_lousingle wavelength detection can miss a co-eluting impurity that does not absorb there#coa-reading · 2025-09-23ferrous_ashthats co-elution#hplc-massspec · 2025-09-23area_percentco-elution is the failure mode that a beautiful single peak is most likely to be hiding#hplc-massspec · 2025-09-24area_percentretention time is a hint, not a fingerprint. two different peptides can co-elute perfectly happily#hplc-massspec · 2025-09-24pinch_not_stretchdoes retention time on its own tell you what the compound is#hplc-massspec · 2025-09-24protein_floordoes retention time on its own tell you what the compound is#hplc-massspec · 2025-09-26chlorhexthats co-elution#hplc-massspec · 2025-09-26chlorhexshallow gradient#hplc-massspec · 2025-09-26shame_and_medssorry to jump in retention time is a hint, not a fingerprint. two different peptides can co-elute perfectly happily#hplc-massspec · 2025-09-26salt_bridgesingle wavelength detection can miss a co-eluting impurity that does not absorb there#coa-reading · 2025-09-28ghent_gradientretention time shifts between runs are normal. relative retention time is the number to compare#coa-reading · 2025-09-30HPLC_Hanksingle wavelength detection can miss a co-eluting impurity that does not absorb there, ask me again in a month#coa-reading · 2025-10-02swirl_not_shakethe retention time on this one is different from the last lot, problem#coa-reading · 2025-10-02area_percentrelative retention time against a standard is comparable between labs. absolute minutes are not#hplc-massspec · 2025-10-05area_percentco-elution is the failure mode that a beautiful single peak is most likely to be hiding#hplc-massspec · 2025-10-05assay_not_puritysingle wavelength detection can miss a co-eluting impurity that does not absorb there#coa-reading · 2025-10-06void_volumefor the archive does retention time on its own tell you what the compound is#hplc-massspec · 2025-10-08void_volumebaseline drift on a gradient is normal. baseline drift on an isocratic hold is your column#hplc-massspec · 2025-10-08void_volumethats co-elution#hplc-massspec · 2025-10-08HPLC_Hankshallow gradient#hplc-massspec · 2025-10-08gradient_gregco-elution is the failure mode that a beautiful single peak is most likely to be hiding#hplc-massspec · 2025-10-08surpass_tworetention time shifts between runs are normal. relative retention time is the number to compare#coa-reading · 2025-10-09endotoxin_edhow do you tell co-elution from a clean single peak#hplc-massspec · 2025-10-09ghent_gradientshallow gradient#hplc-massspec · 2025-10-10hiccup_hollishow do you tell co-elution from a clean single peak#hplc-massspec · 2025-10-10plus_sixteensingle wavelength detection can miss a co-eluting impurity that does not absorb there#coa-reading · 2025-10-11bea_reconstitutesco-elution is the failure mode that a beautiful single peak is most likely to be hiding#hplc-massspec · 2025-10-12coa_or_coperetention time shifts between runs are normal. relative retention time is the number to compare#coa-reading · 2025-10-13auckland_aliquotretention time shifts between runs are normal. relative retention time is the number to compare#coa-reading · 2025-10-14stack_scepticthe retention time on this one is different from the last lot, problem#coa-reading · 2025-10-14chaser_chrisbaseline drift on a gradient is normal. baseline drift on an isocratic hold is your column, thats one data point#hplc-massspec · 2025-10-15blank_runthats co-elution#hplc-massspec · 2025-10-15chaser_chrisretention time is a hint#hplc-massspec · 2025-10-15endotoxin_edsingle wavelength detection can miss a co-eluting impurity that does not absorb there, still working it out#coa-reading · 2025-10-17endotoxin_edhow do you tell co-elution from a clean single peak#hplc-massspec · 2025-10-17coa_or_copesingle wavelength detection can miss a co-eluting impurity that does not absorb there#coa-reading · 2025-10-19assay_not_purityretention time shifts between runs are normal. relative retention time is the number to compare#coa-reading · 2025-10-19bp_down_bexretention time is a hint, not a fingerprint. two different peptides can co-elute perfectly happily#hplc-massspec · 2025-10-22point_two_fiveretention time is a hint#hplc-massspec · 2025-10-23salt_bridgethats co-elution#hplc-massspec · 2025-10-23salt_bridgebaseline drift on a gradient is normal. baseline drift on an isocratic hold is your column, ask me again in a month#hplc-massspec · 2025-10-23two_four_ceilingco-elution is the failure mode that a beautiful single peak is most likely to be hiding, happy to be corrected#hplc-massspec · 2025-10-23salt_bridgesingle wavelength detection can miss a co-eluting impurity that does not absorb there#coa-reading · 2025-10-25warsaw_vialquick one retention time shifts between runs are normal. relative retention time is the number to compare#coa-reading · 2025-10-25new_here_natthats co-elution#hplc-massspec · 2025-10-29ms_ms_mirashallow gradient#hplc-massspec · 2025-10-30ms_ms_miraretention time is a hint#hplc-massspec · 2025-10-30travel_coolerthats co-elution#hplc-massspec · 2025-10-30oasis_olawhats a normal gradient for a peptide this size#hplc-massspec · 2025-10-30plus_sixteenbaseline drift on a gradient is normal. baseline drift on an isocratic hold is your column#hplc-massspec · 2025-10-30ms_ms_mirarelative retention time against a standard is comparable between labs. absolute minutes are not#hplc-massspec · 2025-10-30assay_not_puritythe retention time on this one is different from the last lot, problem#coa-reading · 2025-11-01HPLC_Hankretention time is a hint#hplc-massspec · 2025-11-01monoisotopicdo you trust an area percent from a shallow gradient#hplc-massspec · 2025-11-01lot_number_lousingle wavelength detection can miss a co-eluting impurity that does not absorb there#coa-reading · 2025-11-02