Topic
Retention time
Page 7 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 7 of 15
vialkeeperrelative retention time against a standard is comparable between labs. absolute minutes are not#hplc-massspec · 2025-11-02vialkeeperwhats a normal gradient for a peptide this size#hplc-massspec · 2025-11-02food_noise_offretention time is a hint#hplc-massspec · 2025-11-04peak_splitthats co-elution#hplc-massspec · 2025-11-04first_month_fibaseline drift on a gradient is normal. baseline drift on an isocratic hold is your column#hplc-massspec · 2025-11-04first_month_firetention time is a hint, not a fingerprint. two different peptides can co-elute perfectly happily#hplc-massspec · 2025-11-04acetate_ashshallow gradient#hplc-massspec · 2025-11-04two_lifts_a_weekthe retention time on this one is different from the last lot, problem#coa-reading · 2025-11-06truncation_truretention time is a hint, not a fingerprint. two different peptides can co-elute perfectly happily, for what its worth#hplc-massspec · 2025-11-07font_forensicssingle wavelength detection can miss a co-eluting impurity that does not absorb there#coa-reading · 2025-11-08peak_splitdoes retention time on its own tell you what the compound is#hplc-massspec · 2025-11-08peak_splitright so baseline drift on a gradient is normal. baseline drift on an isocratic hold is your column#hplc-massspec · 2025-11-08sulphur_burpretention time is a hint, not a fingerprint. two different peptides can co-elute perfectly happily#hplc-massspec · 2025-11-08no_appetite_niado you trust an area percent from a shallow gradient#hplc-massspec · 2025-11-08lot_number_louretention time shifts between runs are normal. relative retention time is the number to compare#coa-reading · 2025-11-12blank_runco-elution is the failure mode that a beautiful single peak is most likely to be hiding#hplc-massspec · 2025-11-12endotoxin_edwhats a normal gradient for a peptide this size#hplc-massspec · 2025-11-12blank_runbaseline drift on a gradient is normal. baseline drift on an isocratic hold is your column#hplc-massspec · 2025-11-12HPLC_Hankrelative retention time against a standard is comparable between labs. absolute minutes are not#hplc-massspec · 2025-11-12travel_coolerrelative retention time against a standard is comparable between labs. absolute minutes are not#hplc-massspec · 2025-11-13vik_verifiesquick one do you trust an area percent from a shallow gradient#hplc-massspec · 2025-11-15vik_verifieswhats a normal gradient for a peptide this size co-elution is the failure mode that a beautiful single peak is most likely to…#hplc-massspec · 2025-11-15cricket_or_footyshallow gradient#hplc-massspec · 2025-11-15coa_or_copesingle wavelength detection can miss a co-eluting impurity that does not absorb there#coa-reading · 2025-11-16electrolyte_eliretention time shifts between runs are normal. relative retention time is the number to compare#coa-reading · 2025-11-16declared_valuewhats a normal gradient for a peptide this size#hplc-massspec · 2025-11-16apob_over_ldlbaseline drift on a gradient is normal. baseline drift on an isocratic hold is your column, from memory#hplc-massspec · 2025-11-16vialkeeperretention time is a hint#hplc-massspec · 2025-11-16pinch_not_stretchthats co-elution#hplc-massspec · 2025-11-16verify_or_dontshallow gradient#hplc-massspec · 2025-11-16assay_not_puritygenuine question single wavelength detection can miss a co-eluting impurity that does not absorb there#coa-reading · 2025-11-17relabel_watchdoes retention time on its own tell you what the compound is#hplc-massspec · 2025-11-19relabel_watchdo you trust an area percent from a shallow gradient#hplc-massspec · 2025-11-19area_percentco-elution is the failure mode that a beautiful single peak is most likely to be hiding#hplc-massspec · 2025-11-19thirty_min_waitshallow gradient#hplc-massspec · 2025-11-19underfill_umabaseline drift on a gradient is normal. baseline drift on an isocratic hold is your column#hplc-massspec · 2025-11-21bench_notesthe retention time on this one is different from the last lot, problem#coa-reading · 2025-11-23apnoea_down_twosingle wavelength detection can miss a co-eluting impurity that does not absorb there#coa-reading · 2025-11-24apnoea_down_twothe retention time on this one is different from the last lot, problem#coa-reading · 2025-11-24area_percentrelative retention time against a standard is comparable between labs. absolute minutes are not#hplc-massspec · 2025-11-24monoisotopicdo you trust an area percent from a shallow gradient#hplc-massspec · 2025-11-24area_percentthats co-elution#hplc-massspec · 2025-11-24nine_nine_oneco-elution is the failure mode that a beautiful single peak is most likely to be hiding#hplc-massspec · 2025-11-24ferritin_faythe retention time on this one is different from the last lot, problem i asked SGN for the method and they sent it. that alone…#coa-reading · 2025-11-26fridge_thermorelative retention time against a standard is comparable between labs. absolute minutes are not#hplc-massspec · 2025-11-29fridge_thermobaseline drift on a gradient is normal. baseline drift on an isocratic hold is your column#hplc-massspec · 2025-11-29karl_fischerhow do you tell co-elution from a clean single peak#hplc-massspec · 2025-11-29shame_and_medsshallow gradient#hplc-massspec · 2025-11-29LC_MS_Lenathats co-elution#hplc-massspec · 2025-11-29half_life_halretention time is a hint, not a fingerprint. two different peptides can co-elute perfectly happily, ask me again in a month#hplc-massspec · 2025-11-30coa_or_coperetention time is a hint#hplc-massspec · 2025-12-01still_here_2024retention time is a hint, not a fingerprint. two different peptides can co-elute perfectly happily#hplc-massspec · 2025-12-01courier_vs_postco-elution is the failure mode that a beautiful single peak is most likely to be hiding#hplc-massspec · 2025-12-01gus_chartssingle wavelength detection can miss a co-eluting impurity that does not absorb there#coa-reading · 2025-12-03underfill_umaquick one the retention time on this one is different from the last lot, problem#coa-reading · 2025-12-03pinch_not_stretchretention time is a hint#hplc-massspec · 2025-12-03two_ml_twobaseline drift on a gradient is normal. baseline drift on an isocratic hold is your column#hplc-massspec · 2025-12-03pinch_not_stretchwhats a normal gradient for a peptide this size#hplc-massspec · 2025-12-03two_ml_twoshallow gradient#hplc-massspec · 2025-12-03deamidationdoes retention time on its own tell you what the compound is#hplc-massspec · 2025-12-04