Tags · Technique

MALDI-TOF

Matrix-assisted laser desorption ionisation, common in quick identity checks.

22 topics 11 solved Group: Technique

22 topics

Topic	Participants	Replies	Views	Activity
Isotope patterns and why the monoisotopic peak is not the tallest — does this still hold? Analytics › Mass spectrometry 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. Working through the identity…		2	4.6k	7h
MS/MS sequence confirmation: what it costs and when it is worth it Analytics › Mass spectrometry 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
Second pass at: What a 2 ppm match establishes, and what it does not Analytics › Mass spectrometry MALDI-TOF mass error (ppm) counter-ion content high-resolution MS Second pass at: What a 2 ppm match establishes, and what it does not — setting out what I have, and where I think it stops being reliable. Working through the identity arithmetic and I would like it checked.…	+44	49	8.1k	1d
Mass error in ppm: the arithmetic and the caveat — a second dataset Analytics › Mass spectrometry 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 Analytics › Mass spectrometry 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. Working through the identity…	+34	39	21k	1mo
[2026 update] Charge states for a 4 kDa peptide, worked through Analytics › Mass spectrometry 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? Analytics › Mass spectrometry 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? Posting the method first, because I know what the first three…	+113	119	1.7k	3mo
Second pass at: Counter-ion content and its effect on measured mass Analytics › Mass spectrometry 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. Working through the identity arithmetic and I would like…		4	16k	4mo
Mass error in ppm: the arithmetic and the caveat Analytics › Mass spectrometry 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 Analytics › Mass spectrometry 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. Working through the identity arithmetic and I would like it…		2	18k	7mo
[2026 update] Why mass spectrometry cannot tell you about an epimer Analytics › Mass spectrometry high-resolution MS counter-ion content MALDI-TOF Why mass spectrometry cannot tell you about an epimer — 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…		2	1k	8mo
What a 2 ppm match establishes, and what it does not Analytics › Mass spectrometry 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 Analytics › Mass spectrometry 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 Analytics › Mass spectrometry 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. Working through the identity arithmetic and I would like it checked. retatrutide has a…	+34	38	4.8k	10mo
MALDI versus ESI for a quick identity check Analytics › Mass spectrometry high-resolution MS charge states mass error (ppm) MALDI-TOF Closed On the subject in the title: MALDI versus ESI for a quick identity check Working notes rather than a conclusion. Working through the identity arithmetic and I would like it checked. tirzepatide has a…		2	2k	11mo
Distinguishing a deletion sequence by mass alone — the long version Analytics › Mass spectrometry high-resolution MS mass error (ppm) charge states MALDI-TOF On the subject in the title: Distinguishing a deletion sequence by mass alone — the long version Working notes rather than a conclusion. I would like to understand what this number means before I repeat it…	+38	44	60k	11mo
Counter-ion content and its effect on measured mass Analytics › Mass spectrometry 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. Working through the identity arithmetic and I would like it checked. retatrutide has a…	+100	108	45k	12mo
Adducts: sodium, potassium, and the peak you did not expect Analytics › Mass spectrometry 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. I would like to understand what this number means before I repeat…	+70	77	3.5k	15mo
Oxidation and deamidation mass shifts, tabulated Analytics › Mass spectrometry 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. Working through the identity arithmetic and I would like it checked.…	+67	76	21k	16mo
Isotope patterns and why the monoisotopic peak is not the tallest Analytics › Mass spectrometry 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. Working through the identity arithmetic and I would like it checked.…	+12	16	7.5k	17mo
Distinguishing a deletion sequence by mass alone Analytics › Mass spectrometry 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. Working through the identity arithmetic and I would like it checked.…	+121	129	25k	17mo
High-resolution MS on aggregates and what it can see — one year on Analytics › Mass spectrometry 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. Working through the identity arithmetic and I would like…	+54	58	1.2k	23mo

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