LL-37 impurity profile
Every named species the index has reported alongside LL-37, how often, at what level, and what its presence implies about the synthesis or the handling. Reporting threshold is 0.05 % area; anything below it is invisible to this page and is silently added to the main peak.
Median total impurities
1.39%
n=36
Median largest single
0.72%
n=36
Worst single observed
1.40%
n=36
Named species observed
5 / 5
n=5
| Named species | ΔRT (min) | Δ mass (Da) | Seen in | Median % area | Max % area |
|---|---|---|---|---|---|
| aggregated multimer | +2.85 | mass-identical | 100% | 0.34 | 1.40 |
| des-Leu1 (−113 Da) | -0.38 | -113.084 | 97% | 0.10 | 0.32 |
| deamidated (+1 Da) | -0.26 | +0.984 | 92% | 0.13 | 1.05 |
| trifluoroacetyl adduct (+96 Da) | +0.84 | +95.982 | 92% | 0.08 | 0.24 |
| truncated (1-31) | -1.68 | -709.401 | 89% | 0.51 | 1.25 |
aggregated multimer
- Retention offset from the main peak
- +2.85 min on RG-2
- Mass difference
- mass-identical — chromatography only
- Reported in
- 36 of 36 records (100 %)
- Level when reported
- median 0.34 %, max 1.40 %
- Resolution requirement
- A gradient long enough to separate it. No mass spectrometer will.
des-Leu1 (−113 Da)
- Retention offset from the main peak
- -0.38 min on RG-2
- Mass difference
- -113.084 Da
- Reported in
- 35 of 36 records (97 %)
- Level when reported
- median 0.10 %, max 0.32 %
- Resolution requirement
- Baseline-resolved on the reference method.
deamidated (+1 Da)
- Retention offset from the main peak
- -0.26 min on RG-2
- Mass difference
- +0.984 Da
- Reported in
- 33 of 36 records (92 %)
- Level when reported
- median 0.13 %, max 1.05 %
- Resolution requirement
- Close-eluting — resolution below 1.2 is common and the peaks merge on short gradients.
trifluoroacetyl adduct (+96 Da)
- Retention offset from the main peak
- +0.84 min on RG-2
- Mass difference
- +95.982 Da
- Reported in
- 33 of 36 records (92 %)
- Level when reported
- median 0.08 %, max 0.24 %
- Resolution requirement
- Baseline-resolved on the reference method.
truncated (1-31)
- Retention offset from the main peak
- -1.68 min on RG-2
- Mass difference
- -709.401 Da
- Reported in
- 32 of 36 records (89 %)
- Level when reported
- median 0.51 %, max 1.25 %
- Resolution requirement
- Baseline-resolved on the reference method.
Degradation pathways
Degradants are a handling finding rather than a synthesis finding. A lot that shipped clean and arrived oxidised tells you about the courier, not the chemist.
- self-association into oligomers at physiological ionic strength
- adsorptive loss on polypropylene — use glass