Topic
Retention time
Page 4 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 4 of 15
salt_bridgeright so the retention time on this one is different from the last lot, problem#coa-reading · 2025-06-18residual_solventretention time shifts between runs are normal. relative retention time is the number to compare#coa-reading · 2025-06-18truncation_trurelative retention time against a standard is comparable between labs. absolute minutes are not#hplc-massspec · 2025-06-19truncation_truthats co-elution#hplc-massspec · 2025-06-19void_volumehow do you tell co-elution from a clean single peak#hplc-massspec · 2025-06-19secretagogue_syfor the archive how do you tell co-elution from a clean single peak#hplc-massspec · 2025-06-20patent_2026relative retention time against a standard is comparable between labs. absolute minutes are not#hplc-massspec · 2025-06-20never_for_saleretention time is a hint#hplc-massspec · 2025-06-20void_volumeshallow gradient#hplc-massspec · 2025-06-20third_shiftco-elution is the failure mode that a beautiful single peak is most likely to be hiding, not advice obviously#hplc-massspec · 2025-06-21no_chargebackshallow gradient#hplc-massspec · 2025-06-22no_chargebackok so how do you tell co-elution from a clean single peak#hplc-massspec · 2025-06-22no_chargebackbaseline drift on a gradient is normal. baseline drift on an isocratic hold is your column#hplc-massspec · 2025-06-22area_percentdoes retention time on its own tell you what the compound is#hplc-massspec · 2025-06-22tail_factorthats co-elution#hplc-massspec · 2025-06-22tail_factorthats co-elution#hplc-massspec · 2025-06-26retention_timeslightly off topic but does retention time on its own tell you what the compound is#hplc-massspec · 2025-06-26tail_factorbaseline drift on a gradient is normal. baseline drift on an isocratic hold is your column#hplc-massspec · 2025-06-26nhs_pathway_nellhow do you tell co-elution from a clean single peak#hplc-massspec · 2025-06-26VialBotArchive lookup: coelution_cai first appears in this channel on 2025-01-01.#retatrutide · 2025-06-27courier_vs_postthe retention time on this one is different from the last lot, problem#coa-reading · 2025-07-01third_shiftsingle wavelength detection can miss a co-eluting impurity that does not absorb there#coa-reading · 2025-07-02gradient_gregshallow gradient#hplc-massspec · 2025-07-05hk_hplcbaseline drift on a gradient is normal. baseline drift on an isocratic hold is your column i have had a lot where the mass was…#hplc-massspec · 2025-07-05nine_nine_onewhats a normal gradient for a peptide this size#hplc-massspec · 2025-07-05cagri_curiousretention time is a hint#hplc-massspec · 2025-07-05gradient_greghow do you tell co-elution from a clean single peak#hplc-massspec · 2025-07-05assay_not_purityretention time is a hint#hplc-massspec · 2025-07-06reta_resting_hrsorry to jump in co-elution is the failure mode that a beautiful single peak is most likely to be hiding#hplc-massspec · 2025-07-08reta_resting_hrdoes retention time on its own tell you what the compound is#hplc-massspec · 2025-07-08reta_resting_hrrelative retention time against a standard is comparable between labs. absolute minutes are not, we shall see#hplc-massspec · 2025-07-08LC_MS_Lenawhats a normal gradient for a peptide this size#hplc-massspec · 2025-07-08reta_resting_hrretention time is a hint#hplc-massspec · 2025-07-08hk_hplcfollow up do you trust an area percent from a shallow gradient#hplc-massspec · 2025-07-08split_dose_samretention time shifts between runs are normal. relative retention time is the number to compare#coa-reading · 2025-07-10first_and_last_foursingle wavelength detection can miss a co-eluting impurity that does not absorb there#coa-reading · 2025-07-11monoisotopicretention time shifts between runs are normal. relative retention time is the number to compare tfa counterion runs higher by…#coa-reading · 2025-07-11identity_shiftthe retention time on this one is different from the last lot, problem#coa-reading · 2025-07-12deamidationthats co-elution#hplc-massspec · 2025-07-13chaser_chrishow do you tell co-elution from a clean single peak#hplc-massspec · 2025-07-13gip_glp_gilretention time is a hint#hplc-massspec · 2025-07-15nausea_windowdoes retention time on its own tell you what the compound is#hplc-massspec · 2025-07-19cricket_or_footybaseline drift on a gradient is normal. baseline drift on an isocratic hold is your column#hplc-massspec · 2025-07-19mira_pinsco-elution is the failure mode that a beautiful single peak is most likely to be hiding, ymmv#hplc-massspec · 2025-07-19tb500_tobiasthats co-elution#hplc-massspec · 2025-07-23nausea_windowrelative retention time against a standard is comparable between labs. absolute minutes are not#hplc-massspec · 2025-07-23lower_frequencysingle wavelength detection can miss a co-eluting impurity that does not absorb there#coa-reading · 2025-07-24LC_MS_Lenaretention time is a hint, not a fingerprint. two different peptides can co-elute perfectly happily#hplc-massspec · 2025-07-25pinch_not_stretchwhats a normal gradient for a peptide this size#hplc-massspec · 2025-07-25monoisotopicthats co-elution#hplc-massspec · 2025-07-25HPLC_Hankdoes retention time on its own tell you what the compound is#hplc-massspec · 2025-07-25monoisotopicfollow up do you trust an area percent from a shallow gradient#hplc-massspec · 2025-07-25meal_prep_mickretention time shifts between runs are normal. relative retention time is the number to compare#coa-reading · 2025-07-27coa_or_coperetention time is a hint#hplc-massspec · 2025-07-27meniscus_meldo you trust an area percent from a shallow gradient#hplc-massspec · 2025-07-27cold_chain_cmdrthats co-elution#hplc-massspec · 2025-07-27assay_not_puritygenuine question how do you tell co-elution from a clean single peak#hplc-massspec · 2025-07-27cold_chain_cmdrwhats a normal gradient for a peptide this size#hplc-massspec · 2025-07-27vial_ledgerdo you trust an area percent from a shallow gradient#hplc-massspec · 2025-07-28halifax_hplcthats co-elution#hplc-massspec · 2025-07-28