Epitalon impurity profile
Every named species the index has reported alongside Epitalon, 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
1.37%
n=37
Median largest single
0.84%
n=37
Worst single observed
1.76%
n=37
Named species observed
4 / 4
n=4
| Named species | ΔRT (min) | Δ mass (Da) | Seen in | Median % area | Max % area |
|---|---|---|---|---|---|
| aspartimide (−18 Da) | +0.12 | -18.011 | 97% | 0.19 | 1.66 |
| Ala-Glu-Asp tripeptide (−57 Da) | -0.20 | -57.021 | 95% | 0.27 | 1.76 |
| diketopiperazine (−18 Da) | +0.16 | -18.011 | 95% | 0.14 | 0.99 |
| β-Asp isomer | -0.10 | mass-identical | 92% | 0.25 | 1.35 |
aspartimide (−18 Da)
- Retention offset from the main peak
- +0.12 min on RG-2
- Mass difference
- -18.011 Da
- Reported in
- 36 of 37 records (97 %)
- Level when reported
- median 0.19 %, max 1.66 %
- Resolution requirement
- Close-eluting — resolution below 1.2 is common and the peaks merge on short gradients.
Ala-Glu-Asp tripeptide (−57 Da)
- Retention offset from the main peak
- -0.20 min on RG-2
- Mass difference
- -57.021 Da
- Reported in
- 35 of 37 records (95 %)
- Level when reported
- median 0.27 %, max 1.76 %
- Resolution requirement
- Close-eluting — resolution below 1.2 is common and the peaks merge on short gradients.
diketopiperazine (−18 Da)
- Retention offset from the main peak
- +0.16 min on RG-2
- Mass difference
- -18.011 Da
- Reported in
- 35 of 37 records (95 %)
- Level when reported
- median 0.14 %, max 0.99 %
- Resolution requirement
- Close-eluting — resolution below 1.2 is common and the peaks merge on short gradients.
β-Asp isomer
- Retention offset from the main peak
- -0.10 min on RG-2
- Mass difference
- mass-identical — chromatography only
- Reported in
- 34 of 37 records (92 %)
- Level when reported
- median 0.25 %, max 1.35 %
- Resolution requirement
- A gradient long enough to separate it. No mass spectrometer 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.
- Asp-Gly aspartimide, then hydrolysis to the β-Asp isomer — the classic tetrapeptide problem