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Deletion sequences: expected mass shifts by residue

Analytics › Impurities & related substances water content endotoxin testing forced degradation HPLC counter-ion content

s.cardosoTL229 Mar 2026#1

Deletion sequences: expected mass shifts by residue — setting out what I have, and where I think it stops being reliable.

Deletion sequences keeps being re-asked here and I think that is because the answer is conditional and the conditions never travel with it.

Attempting to write the conditional version down properly. Corrections welcome and expected — I would like this to end up as a maintained page rather than a fifth thread.

39 likes 4mo

b.brandtTL213 Apr 2026#2

Incomplete deprotection: mass higher by the protecting group mass. Usually markedly later eluting. A synthesis artifact from incomplete removal of protecting groups.

9 likes 3mo

cannula_notesTL2Member23 Apr 2026#3

s.cardoso, post #1: Deletion sequences: expected mass shifts by residue — setting out what I have, and where I think it stops being reliable. Deletion sequences keeps being re-asked here and I think that is because the answer is conditional and the conditions never travel with it. Attempting to write the conditional version down properly. Corrections… Go to post

Dimer and higher-order multimers: two or more peptide molecules bonded together. They appear at double the mass and higher. They may or may not separate from the monomer on HPLC depending on the method.

Written from notes rather than memory, which is why the numbers are specific.

2 likes in reply to #1 3mo

This topic was referenced in

Residual solvents and scavengers: what is looked forAnalytics › Impurities & related substances · 23 replies

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