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
1.10%
n=17
Median largest single
0.68%
n=17
Worst single observed
1.13%
n=17
Named species observed
5 / 5
n=5
| Named species | ΔRT (min) | Δ mass (Da) | Seen in | Median % area | Max % area |
|---|---|---|---|---|---|
| truncated (1-31) | -1.68 | -709.401 | 100% | 0.05 | 1.13 |
| des-Leu1 (−113 Da) | -0.38 | -113.084 | 100% | 0.37 | 0.89 |
| deamidated (+1 Da) | -0.26 | +0.984 | 100% | 0.16 | 0.33 |
| trifluoroacetyl adduct (+96 Da) | +0.84 | +95.982 | 100% | 0.06 | 0.15 |
| aggregated multimer | +2.85 | mass-identical | 94% | 0.21 | 1.10 |
truncated (1-31)
- Retention offset from the main peak
- -1.68 min on RG-2
- Mass difference
- -709.401 Da
- Reported in
- 17 of 17 records (100 %)
- Level when reported
- median 0.05 %, max 1.13 %
- How it separates
- Baseline-resolved on the reference method.
des-Leu1 (−113 Da)
- Retention offset from the main peak
- -0.38 min on RG-2
- Mass difference
- -113.084 Da
- Reported in
- 17 of 17 records (100 %)
- Level when reported
- median 0.37 %, max 0.89 %
- How it separates
- 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
- 17 of 17 records (100 %)
- Level when reported
- median 0.16 %, max 0.33 %
- How it separates
- Close-eluting on the reference method, and merged with the main peak on a short gradient. The index prints the resolution figure for such a pair and applies no criterion to it — where the two are not separated, what matters is that the integration convention is stated.
trifluoroacetyl adduct (+96 Da)
- Retention offset from the main peak
- +0.84 min on RG-2
- Mass difference
- +95.982 Da
- Reported in
- 17 of 17 records (100 %)
- Level when reported
- median 0.06 %, max 0.15 %
- How it separates
- Baseline-resolved on the reference method.
aggregated multimer
- Retention offset from the main peak
- +2.85 min on RG-2
- Mass difference
- mass-identical — chromatography only
- Reported in
- 16 of 17 records (94 %)
- Level when reported
- median 0.21 %, max 1.10 %
- How it separates
- Chromatography only. A gradient long enough to separate it; no mass spectrometer of any resolution will.
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