Topic
Retention time
Page 3 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 3 of 15
LC_MS_Lenawhats a normal gradient for a peptide this size#hplc-massspec · 2025-04-28karl_fischerretention time is a hint#hplc-massspec · 2025-05-01LC_MS_Lenadoes retention time on its own tell you what the compound is#hplc-massspec · 2025-05-01yyz_vialco-elution is the failure mode that a beautiful single peak is most likely to be hiding#hplc-massspec · 2025-05-01apnoea_down_twodo you trust an area percent from a shallow gradient#hplc-massspec · 2025-05-03area_percentco-elution is the failure mode that a beautiful single peak is most likely to be hiding#hplc-massspec · 2025-05-03retention_timeright so how do you tell co-elution from a clean single peak#hplc-massspec · 2025-05-04week_three_wallwhile im here relative retention time against a standard is comparable between labs. absolute minutes are not, happy to be…#hplc-massspec · 2025-05-04retention_timethats co-elution#hplc-massspec · 2025-05-04area_percentdoes retention time on its own tell you what the compound is#hplc-massspec · 2025-05-04alcohol_hitsright so retention time shifts between runs are normal. relative retention time is the number to compare, we shall see#coa-reading · 2025-05-05group_buy_gwenrelative retention time against a standard is comparable between labs. absolute minutes are not#hplc-massspec · 2025-05-07combo_cairetention time is a hint#hplc-massspec · 2025-05-07stopped_and_regainedsingle wavelength detection can miss a co-eluting impurity that does not absorb there#coa-reading · 2025-05-10monoisotopicthats co-elution#hplc-massspec · 2025-05-10hiccup_hollisrelative retention time against a standard is comparable between labs. absolute minutes are not the first peak is the solvent.…#hplc-massspec · 2025-05-10deamidationretention time is a hint, not a fingerprint. two different peptides can co-elute perfectly happily#hplc-massspec · 2025-05-10hiccup_holliswhats a normal gradient for a peptide this size#hplc-massspec · 2025-05-10half_life_halshallow gradient#hplc-massspec · 2025-05-10noct.titrateshallow gradient#hplc-massspec · 2025-05-13tb500_tobiasrelative retention time against a standard is comparable between labs. absolute minutes are not, anyway#hplc-massspec · 2025-05-13noct.titratethats co-elution#hplc-massspec · 2025-05-13tb500_tobiasretention time is a hint, not a fingerprint. two different peptides can co-elute perfectly happily#hplc-massspec · 2025-05-13LC_MS_Lenaretention time shifts between runs are normal. relative retention time is the number to compare#coa-reading · 2025-05-16gradient_gregright so single wavelength detection can miss a co-eluting impurity that does not absorb there#coa-reading · 2025-05-16sharps_bin_sidcoming back to this relative retention time against a standard is comparable between labs. absolute minutes are not#hplc-massspec · 2025-05-16gradient_gregwhats a normal gradient for a peptide this size#hplc-massspec · 2025-05-16acetate_ashdo you trust an area percent from a shallow gradient#hplc-massspec · 2025-05-16gradient_gregthats co-elution#hplc-massspec · 2025-05-16dexa_or_biathe retention time on this one is different from the last lot, problem#coa-reading · 2025-05-21point_two_fiveretention time shifts between runs are normal. relative retention time is the number to compare#coa-reading · 2025-05-23perth_pinthe retention time on this one is different from the last lot, problem#coa-reading · 2025-05-23septum_salbaseline drift on a gradient is normal. baseline drift on an isocratic hold is your column#hplc-massspec · 2025-05-25rezept_rolfrelative retention time against a standard is comparable between labs. absolute minutes are not#hplc-massspec · 2025-05-25third_shiftsingle wavelength detection can miss a co-eluting impurity that does not absorb there#coa-reading · 2025-05-29coa_or_copesingle wavelength detection can miss a co-eluting impurity that does not absorb there#coa-reading · 2025-06-02LC_MS_Lenasorry to jump in do you trust an area percent from a shallow gradient#hplc-massspec · 2025-06-05identity_shiftthats co-elution#hplc-massspec · 2025-06-05identity_shiftwhile im here relative retention time against a standard is comparable between labs. absolute minutes are not#hplc-massspec · 2025-06-05identity_shiftwhats a normal gradient for a peptide this size#hplc-massspec · 2025-06-05quiet.hoursretention time is a hint#hplc-massspec · 2025-06-05pbs_pipsingle wavelength detection can miss a co-eluting impurity that does not absorb there#coa-reading · 2025-06-07pbs_pipthe retention time on this one is different from the last lot, problem#coa-reading · 2025-06-07tail_factorco-elution is the failure mode that a beautiful single peak is most likely to be hiding#hplc-massspec · 2025-06-08LC_MS_Lenabaseline drift on a gradient is normal. baseline drift on an isocratic hold is your column#hplc-massspec · 2025-06-08cold_start_cythats co-elution#hplc-massspec · 2025-06-08u100_patretention time shifts between runs are normal. relative retention time is the number to compare#coa-reading · 2025-06-11egfr_edhow do you tell co-elution from a clean single peak#hplc-massspec · 2025-06-11egfr_edshallow gradient#hplc-massspec · 2025-06-11acetate_ashright so co-elution is the failure mode that a beautiful single peak is most likely to be hiding, anyway#hplc-massspec · 2025-06-11is_this_foreverthats co-elution#hplc-massspec · 2025-06-12monoisotopicbaseline drift on a gradient is normal. baseline drift on an isocratic hold is your column#hplc-massspec · 2025-06-12monoisotopicdo you trust an area percent from a shallow gradient#hplc-massspec · 2025-06-12assay_not_purityrelative retention time against a standard is comparable between labs. absolute minutes are not#hplc-massspec · 2025-06-12VialBotReminder for coelution_cai: dose day is today. Set 5 days ago.#vendor-talk · 2025-06-13seizure_letterbaseline drift on a gradient is normal. baseline drift on an isocratic hold is your column#hplc-massspec · 2025-06-14seizure_letterrelative retention time against a standard is comparable between labs. absolute minutes are not#hplc-massspec · 2025-06-14triple_ag_tomslightly off topic but how do you tell co-elution from a clean single peak#hplc-massspec · 2025-06-14seizure_letterretention time is a hint#hplc-massspec · 2025-06-14salt_bridgeretention time is a hint#hplc-massspec · 2025-06-16