Intersection · Analytics × LC-MS

Analytics topics tagged LC-MS

Topics in Analytics carrying the tag LC-MS. Liquid chromatography coupled to mass spectrometry.

23 topics

Topic	Participants	Replies	Views	Activity
About the Mass spectrometry category LC-MS high-resolution MS mass error (ppm) Pinned Wiki LC-MS and high-resolution MS, charge states, mass accuracy in ppm, and what identity confirmation does and does not establish. This post is a community wiki: any member at trust level 3 or above can edit it,…	+5	9	19k	6h
Isotope patterns and why the monoisotopic peak is not the tallest — does this still hold? charge states counter-ion content high-resolution MS mass error (ppm) Solved Isotope patterns and why the monoisotopic peak is not the tallest — does this still hold? — that is the question, and I have not found it answered plainly anywhere I have looked. Asking about Isotope patterns…		2	4.6k	7h
MS/MS sequence confirmation: what it costs and when it is worth it LC-MS MALDI-TOF charge states Solved Pinned MS/MS sequence confirmation: what it costs and when it is worth it — setting out what I have, and where I think it stops being reliable. I would like to understand what this number means before I repeat it…	+2	6	2.7k	1d
Mass error in ppm: the arithmetic and the caveat — a second dataset counter-ion content mass error (ppm) charge states LC-MS Solved On the subject in the title: Mass error in ppm: the arithmetic and the caveat — a second dataset Working notes rather than a conclusion. Working through the identity arithmetic and I would like it checked.…	+20	24	1.7k	1d
MS/MS sequence confirmation: what it costs and when it is worth it — what changed since charge states LC-MS MALDI-TOF counter-ion content Closed Posting this under the heading it deserves: MS/MS sequence confirmation: what it costs and when it is worth it — what changed since Everything below is what sits behind that. Two reports on the same lot, and…	+34	39	21k	1mo
[2026 update] Charge states for a 4 kDa peptide, worked through counter-ion content MALDI-TOF high-resolution MS LC-MS On the subject in the title: Charge states for a 4 kDa peptide, worked through Working notes rather than a conclusion. Working through the identity arithmetic and I would like it checked. semaglutide has a…	+116	135	31k	3mo
Adducts: sodium, potassium, and the peak you did not expect — does this still hold? high-resolution MS charge states mass error (ppm) MALDI-TOF Solved Asking directly, because I could not find a straight answer: Adducts: sodium, potassium, and the peak you did not expect — does this still hold? Adducts keeps being re-asked here and I think that is because…	+113	119	1.7k	3mo
Charge states for a 4 kDa peptide, worked through — the long version LC-MS high-resolution MS mass error (ppm) Charge states for a 4 kDa peptide, worked through — the long version Writing it up because I had to work it out twice and would rather nobody else did. Working through the identity arithmetic and I would like…		2	293	3mo
Second pass at: Counter-ion content and its effect on measured mass mass error (ppm) counter-ion content MALDI-TOF charge states Solved Second pass at: Counter-ion content and its effect on measured mass Writing it up because I had to work it out twice and would rather nobody else did. Something about Counter-ion content does not reconcile…		4	16k	4mo
Mass error in ppm: the arithmetic and the caveat LC-MS high-resolution MS MALDI-TOF counter-ion content Solved Mass error in ppm: the arithmetic and the caveat Writing it up because I had to work it out twice and would rather nobody else did. Working through the identity arithmetic and I would like it checked.…	+108	125	1.5k	5mo
Second pass at: MALDI versus ESI for a quick identity check MALDI-TOF mass error (ppm) high-resolution MS counter-ion content Solved Second pass at: MALDI versus ESI for a quick identity check Writing it up because I had to work it out twice and would rather nobody else did. Something about MALDI versus ESI does not reconcile and I would…		2	18k	7mo
What a 2 ppm match establishes, and what it does not high-resolution MS charge states LC-MS MALDI-TOF What a 2 ppm match establishes, and what it does not — that is the question, and I have not found it answered plainly anywhere I have looked. Working through the identity arithmetic and I would like it…	+56	60	5.2k	9mo
Deconvolution of a multiply charged envelope MALDI-TOF charge states mass error (ppm) counter-ion content Closed Deconvolution of a multiply charged envelope — setting out what I have, and where I think it stops being reliable. Working through the identity arithmetic and I would like it checked. tirzepatide has a…		2	63	10mo
Coming back to: Oxidation and deamidation mass shifts, tabulated LC-MS charge states MALDI-TOF high-resolution MS Oxidation and deamidation mass shifts, tabulated — setting out what I have, and where I think it stops being reliable. Reading back through what has been written here about Oxidation and deamidation mass…	+34	38	4.8k	10mo
Counter-ion content and its effect on measured mass high-resolution MS charge states MALDI-TOF LC-MS Solved On the subject in the title: Counter-ion content and its effect on measured mass Working notes rather than a conclusion. Something about counter-ion content does not reconcile and I would like a second pair…	+100	108	45k	12mo
Adducts: sodium, potassium, and the peak you did not expect LC-MS MALDI-TOF mass error (ppm) Wiki Adducts: sodium, potassium, and the peak you did not expect Writing it up because I had to work it out twice and would rather nobody else did. Adducts keeps being re-asked here and I think that is because the…	+70	77	3.5k	15mo
Oxidation and deamidation mass shifts, tabulated counter-ion content charge states LC-MS mass error (ppm) Solved Posting this under the heading it deserves: Oxidation and deamidation mass shifts, tabulated Everything below is what sits behind that. Oxidation and deamidation mass shifts, and specifically the version of…	+67	76	21k	16mo
Charge states for a 4 kDa peptide, worked through high-resolution MS counter-ion content charge states LC-MS Solved On the subject in the title: Charge states for a 4 kDa peptide, worked through Working notes rather than a conclusion. Working through the identity arithmetic and I would like it checked. retatrutide has a…	+124	146	15k	16mo
Why mass spectrometry cannot tell you about an epimer LC-MS mass error (ppm) high-resolution MS charge states Why mass spectrometry cannot tell you about an epimer I have a specific reason for asking rather than idle curiosity, and the context is below. I have spent a fortnight trying to pin mass spectrometry down…	+75	82	4k	17mo
Isotope patterns and why the monoisotopic peak is not the tallest LC-MS MALDI-TOF mass error (ppm) high-resolution MS Isotope patterns and why the monoisotopic peak is not the tallest — setting out what I have, and where I think it stops being reliable. Isotope patterns: what I expected, what I found, and the gap between…	+12	16	7.5k	17mo
Distinguishing a deletion sequence by mass alone mass error (ppm) high-resolution MS LC-MS MALDI-TOF Solved Distinguishing a deletion sequence by mass alone Writing it up because I had to work it out twice and would rather nobody else did. Trying to establish the boundary conditions on distinguishing a deletion…	+121	129	25k	17mo
Reading an MS report that only gives you a single number — the long version mass error (ppm) counter-ion content LC-MS high-resolution MS Reading an MS report that only gives you a single number — the long version — setting out what I have, and where I think it stops being reliable. I would like to understand what this number means before I…		2	47k	18mo
High-resolution MS on aggregates and what it can see — one year on LC-MS counter-ion content MALDI-TOF charge states Solved High-resolution MS on aggregates and what it can see — one year on Writing it up because I had to work it out twice and would rather nobody else did. A narrow question about High-resolution, deliberately…	+54	58	1.2k	23mo

Sponsored PeptideMeter — peptide analytics and supplier verificationPurity analysis and structured supplier verification, published as dated records rather than scores. Referenced throughout our sourcing documentation.View analytics →