Topic
Retention time
Page 2 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 2 of 15
void_volumethats co-elution#hplc-massspec · 2025-03-02HPLC_Hanksingle wavelength detection can miss a co-eluting impurity that does not absorb there#coa-reading · 2025-03-03seizure_letterwhats a normal gradient for a peptide this size#hplc-massspec · 2025-03-04seizure_letterrelative retention time against a standard is comparable between labs. absolute minutes are not#hplc-massspec · 2025-03-04brisbane_bacdoes retention time on its own tell you what the compound is#hplc-massspec · 2025-03-04gall_bladder_gavco-elution is the failure mode that a beautiful single peak is most likely to be hiding#hplc-massspec · 2025-03-06mag_citratesingle wavelength detection can miss a co-eluting impurity that does not absorb there#coa-reading · 2025-03-08bea_reconstituteswhats a normal gradient for a peptide this size#hplc-massspec · 2025-03-10stack_scepticbaseline drift on a gradient is normal. baseline drift on an isocratic hold is your column#hplc-massspec · 2025-03-10cat_on_the_trayretention time is a hint, not a fingerprint. two different peptides can co-elute perfectly happily#hplc-massspec · 2025-03-10peak_splithow do you tell co-elution from a clean single peak update from 8 months ago: switched to asking for the chromatogram rather…#hplc-massspec · 2025-03-10chain_of_custodyretention time shifts between runs are normal. relative retention time is the number to compare#coa-reading · 2025-03-19ms_ms_miraretention time is a hint#hplc-massspec · 2025-03-19ms_ms_mirawhats a normal gradient for a peptide this size#hplc-massspec · 2025-03-19ferritin_fayunrelated but retention time is a hint, not a fingerprint. two different peptides can co-elute perfectly happily relative…#hplc-massspec · 2025-03-19ferritin_faydo you trust an area percent from a shallow gradient#hplc-massspec · 2025-03-19salt_bridgecode block#scam-watch · 2025-03-19retention_timewhats a normal gradient for a peptide this size#hplc-massspec · 2025-03-21mg_per_mlshallow gradient#hplc-massspec · 2025-03-21HPLC_Hankco-elution is the failure mode that a beautiful single peak is most likely to be hiding#hplc-massspec · 2025-03-25meal_prep_mickok so relative retention time against a standard is comparable between labs. absolute minutes are not, ask me again in a month#hplc-massspec · 2025-03-26meal_prep_mickshallow gradient#hplc-massspec · 2025-03-26apnoea_down_twobaseline drift on a gradient is normal. baseline drift on an isocratic hold is your column#hplc-massspec · 2025-03-29void_volumedo you trust an area percent from a shallow gradient deamidation is about plus 0.98 Da. it is not a rounding error, it is a…#hplc-massspec · 2025-03-29void_volumewhats a normal gradient for a peptide this size#hplc-massspec · 2025-03-29coa_or_copesingle wavelength detection can miss a co-eluting impurity that does not absorb there, happy to be corrected#coa-reading · 2025-03-30salt_bridgethats co-elution#hplc-massspec · 2025-03-30amylin_amyshallow gradient#hplc-massspec · 2025-03-30salt_bridgeunrelated but whats a normal gradient for a peptide this size#hplc-massspec · 2025-04-01madrid_mgco-elution is the failure mode that a beautiful single peak is most likely to be hiding#hplc-massspec · 2025-04-01madrid_mgthats co-elution#hplc-massspec · 2025-04-01LC_MS_Lenahow do you tell co-elution from a clean single peak#hplc-massspec · 2025-04-08peak_splitwhats a normal gradient for a peptide this size#hplc-massspec · 2025-04-12vialkeeperdoes retention time on its own tell you what the compound is#hplc-massspec · 2025-04-12eat_more_pleaseretention time shifts between runs are normal. relative retention time is the number to compare, i think#coa-reading · 2025-04-13typosquat_taythe retention time on this one is different from the last lot, problem no lot number, no certificate. a document you cannot…#coa-reading · 2025-04-13cold_chain_cmdrretention time is a hint#hplc-massspec · 2025-04-14alt_ast_aliretention time is a hint#hplc-massspec · 2025-04-15alt_ast_alihow do you tell co-elution from a clean single peak#hplc-massspec · 2025-04-15freeze_thawdoes retention time on its own tell you what the compound is#hplc-massspec · 2025-04-15relabel_watchbaseline drift on a gradient is normal. baseline drift on an isocratic hold is your column#hplc-massspec · 2025-04-15relabel_watchretention time is a hint, not a fingerprint. two different peptides can co-elute perfectly happily, n of 1 obviously#hplc-massspec · 2025-04-15deamidationsorry to jump in single wavelength detection can miss a co-eluting impurity that does not absorb there#coa-reading · 2025-04-19peak_splitthe retention time on this one is different from the last lot, problem#coa-reading · 2025-04-19shame_and_medsretention time shifts between runs are normal. relative retention time is the number to compare#coa-reading · 2025-04-19ten_of_tencoming back to this baseline drift on a gradient is normal. baseline drift on an isocratic hold is your column#hplc-massspec · 2025-04-19ten_of_tendoes retention time on its own tell you what the compound is#hplc-massspec · 2025-04-19void_volumeretention time is a hint, not a fingerprint. two different peptides can co-elute perfectly happily#hplc-massspec · 2025-04-19plus_sixteenretention time is a hint#hplc-massspec · 2025-04-20monoisotopichow do you tell co-elution from a clean single peak#hplc-massspec · 2025-04-20rezept_rolfso the shallow gradient thing from the other conversation matters here specifically#hplc-massspec · 2025-04-20fake_trackingdoes retention time on its own tell you what the compound is 214nm sees the amide backbone so it sees everything. 280 only…#hplc-massspec · 2025-04-26fake_trackingco-elution is the failure mode that a beautiful single peak is most likely to be hiding#hplc-massspec · 2025-04-26truncation_truretention time is a hint#hplc-massspec · 2025-04-26LC_MS_Lenarelative retention time against a standard is comparable between labs. absolute minutes are not#hplc-massspec · 2025-04-26alcohol_hitswhats a normal gradient for a peptide this size#hplc-massspec · 2025-04-26hair_month_fourthe retention time on this one is different from the last lot, problem#coa-reading · 2025-04-28LC_MS_Lenado you trust an area percent from a shallow gradient#hplc-massspec · 2025-04-28LC_MS_Lenadoes retention time on its own tell you what the compound is#hplc-massspec · 2025-04-28LC_MS_Lenaretention time is a hint#hplc-massspec · 2025-04-28