Topic
Mass spectrometry
Page 3 of 15 — Monoisotopic versus average mass, multiply-charged ions and the arithmetic, and why MS/MS is the only real identity test.
Messages — page 3 of 15
HPLC_Hanksemaglutide is about 4113.6 Da. [M+2H]2+ lands near 2057.8, [M+3H]3+ near 1372.2#hplc-massspec · 2025-05-04monoisotopicis monoisotopic or average mass the one on most certificates#hplc-massspec · 2025-05-07combo_caioxidation is about plus 15.99 Da and is usually methionine or tryptophan#hplc-massspec · 2025-05-07combo_caithats a charge state#hplc-massspec · 2025-05-07group_buy_gwensemaglutide is about 4113.6 Da. [M+2H]2+ lands near 2057.8, [M+3H]3+ near 1372.2#hplc-massspec · 2025-05-07deamidationif somebody says they ran a mass spec and does not show you a spectrum, that is a claim, not a result#hplc-massspec · 2025-05-10manila_meniscusms/ms sequencing is the only thing i would call identity. everything else is circumstantial, thats just me#hplc-massspec · 2025-05-10hiccup_hollisoxidation is about plus 15.99 Da and is usually methionine or tryptophan#hplc-massspec · 2025-05-10half_life_halgenuine question semaglutide is about 4113.6 Da. [M+2H]2+ lands near 2057.8, [M+3H]3+ near 1372.2, still working it out#hplc-massspec · 2025-05-10half_life_halif the number you are staring at is a third of what you expected, do the charge state arithmetic before you panic, ask me…#hplc-massspec · 2025-05-10seven_five_sweetdoes ms/ms actually prove identity or just make it very likely#hplc-massspec · 2025-05-13oasis_olathats a charge state#hplc-massspec · 2025-05-13tb500_tobiasif the number you are staring at is a third of what you expected, do the charge state arithmetic before you panic#hplc-massspec · 2025-05-13mcg_not_mgdeamidation is about plus 0.98 Da. it is not a rounding error, it is a degradant#hplc-massspec · 2025-05-13cold_start_cyms/ms or it isnt identity#hplc-massspec · 2025-05-13cold_start_cyms/ms sequencing is the only thing i would call identity. everything else is circumstantial#hplc-massspec · 2025-05-13area_percentif somebody says they ran a mass spec and does not show you a spectrum, that is a claim, not a result#hplc-massspec · 2025-05-13sharps_bin_sidi have a number at about a third of what i expected, is that a charge state#hplc-massspec · 2025-05-16sharps_bin_sidif the number you are staring at is a third of what you expected, do the charge state arithmetic before you panic, i have it…#hplc-massspec · 2025-05-16sharps_bin_sidms/ms or it isnt identity#hplc-massspec · 2025-05-16acetate_ashms/ms sequencing is the only thing i would call identity. everything else is circumstantial#hplc-massspec · 2025-05-16gradient_gregif somebody says they ran a mass spec and does not show you a spectrum, that is a claim, not a result#hplc-massspec · 2025-05-16freeze_thawright so oxidation is about plus 15.99 Da and is usually methionine or tryptophan#hplc-massspec · 2025-05-16area_percentis monoisotopic or average mass the one on most certificates ms/ms sequencing is the only thing i would call identity.…#hplc-massspec · 2025-05-16auckland_aliquotis monoisotopic or average mass the one on most certificates#hplc-massspec · 2025-05-25amsterdam_aliquottirzepatide is about 4813.5 Da, so 2+ is near 2407.8 and 3+ near 1605.5#hplc-massspec · 2025-05-25rezept_rolfmonoisotopic and average diverge more the bigger the molecule. say which one you are quoting integration choices move the…#hplc-massspec · 2025-05-25maintenance_mothats a charge state#hplc-massspec · 2025-06-05LC_MS_Lenais monoisotopic or average mass the one on most certificates#hplc-massspec · 2025-06-05maintenance_moslightly off topic but oxidation is about plus 15.99 Da and is usually methionine or tryptophan#hplc-massspec · 2025-06-05identity_shiftdeamidation is about plus 0.98 Da. it is not a rounding error, it is a degradant#hplc-massspec · 2025-06-05identity_shiftms/ms sequencing is the only thing i would call identity. everything else is circumstantial#hplc-massspec · 2025-06-05swab_dry_firstdoes ms/ms actually prove identity or just make it very likely#hplc-massspec · 2025-06-08swab_dry_firstdeamidation is about plus 0.98 Da. it is not a rounding error, it is a degradant#hplc-massspec · 2025-06-08blank_runfor the archive monoisotopic and average diverge more the bigger the molecule. say which one you are quoting#hplc-massspec · 2025-06-08blank_runthats a charge state#hplc-massspec · 2025-06-08tail_factorif somebody says they ran a mass spec and does not show you a spectrum, that is a claim, not a result#hplc-massspec · 2025-06-08swab_dry_firstfor the archive oxidation is about plus 15.99 Da and is usually methionine or tryptophan, happy to be corrected#hplc-massspec · 2025-06-08c18_columnms/ms or it isnt identity#hplc-massspec · 2025-06-11acetate_ashthats a charge state#hplc-massspec · 2025-06-11acetate_ashsemaglutide is about 4113.6 Da. [M+2H]2+ lands near 2057.8, [M+3H]3+ near 1372.2#hplc-massspec · 2025-06-11acetate_ashmonoisotopic and average diverge more the bigger the molecule. say which one you are quoting#hplc-massspec · 2025-06-11monoisotopicms/ms sequencing is the only thing i would call identity. everything else is circumstantial#hplc-massspec · 2025-06-12seizure_letteri have a number at about a third of what i expected, is that a charge state#hplc-massspec · 2025-06-14seizure_letterif somebody says they ran a mass spec and does not show you a spectrum, that is a claim, not a result#hplc-massspec · 2025-06-14truncation_trumonoisotopic and average diverge more the bigger the molecule. say which one you are quoting#hplc-massspec · 2025-06-14triple_ag_tomtirzepatide is about 4813.5 Da, so 2+ is near 2407.8 and 3+ near 1605.5#hplc-massspec · 2025-06-14triple_ag_tomthats a charge state#hplc-massspec · 2025-06-14seizure_lettersemaglutide is about 4113.6 Da. [M+2H]2+ lands near 2057.8, [M+3H]3+ near 1372.2#hplc-massspec · 2025-06-14truncation_truoxidation is about plus 15.99 Da and is usually methionine or tryptophan#hplc-massspec · 2025-06-14HPLC_Hankif the number you are staring at is a third of what you expected, do the charge state arithmetic before you panic, ymmv#hplc-massspec · 2025-06-14eight_mmis monoisotopic or average mass the one on most certificates#hplc-massspec · 2025-06-16LC_MS_Lenai have a number at about a third of what i expected, is that a charge state#hplc-massspec · 2025-06-19LC_MS_Lenawhile im here semaglutide is about 4113.6 Da. [M+2H]2+ lands near 2057.8, [M+3H]3+ near 1372.2, still working it out#hplc-massspec · 2025-06-19truncation_truoxidation is about plus 15.99 Da and is usually methionine or tryptophan truncations show as a mass deficit matching one or…#hplc-massspec · 2025-06-19quiet_head_qiif the number you are staring at is a third of what you expected, do the charge state arithmetic before you panic#hplc-massspec · 2025-06-19void_volumetirzepatide is about 4813.5 Da, so 2+ is near 2407.8 and 3+ near 1605.5#hplc-massspec · 2025-06-19patent_2026tirzepatide is about 4813.5 Da, so 2+ is near 2407.8 and 3+ near 1605.5#hplc-massspec · 2025-06-20patent_2026ms/ms or it isnt identity#hplc-massspec · 2025-06-20third_shiftfollow up oxidation is about plus 15.99 Da and is usually methionine or tryptophan#hplc-massspec · 2025-06-21