truncations show as a mass deficit matching one or more residues. you need the sequence to say which
#hplc-massspec 2025-07-19
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the first peak is the solvent. it is always the solvent, i could be wrong
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deamidation is about plus 0.98 Da. it is not a rounding error, it is a degradant
does retention time on its own tell you what the compound is
New independent result logged — KP, lot C-4402, purity 96.8% (Janoshik).
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how do you spot a deletion in a sequence from mass alone
M = 4113.6
[M+2H]2+ = (4113.6 + 2.02) / 2 = 2057.8
[M+3H]3+ = (4113.6 + 3.02) / 3 = 1372.2
observed 1372.3 -> consistentupdate on the earlier thing nobody runs enough blanks, including me, i have it written down somewhere
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plus 16 is oxidation
baseline drift on a gradient is normal. baseline drift on an isocratic hold is your column
ms/ms sequencing is the only thing i would call identity. everything else is circumstantial, anyway
[edited]co-elution is the failure mode that a beautiful single peak is most likely to be hiding, ymmv
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is monoisotopic or average mass the one on most certificates