Semax impurity profile
Every named species the index has reported alongside Semax, 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
0.83%
n=160
Median largest single
0.46%
n=160
Worst single observed
1.51%
n=160
Named species observed
4 / 4
n=4
| Named species | ΔRT (min) | Δ mass (Da) | Seen in | Median % area | Max % area |
|---|---|---|---|---|---|
| des-Met (−131 Da) | +0.20 | -131.040 | 94% | 0.09 | 0.91 |
| N-acetyl semax (+42 Da) | +0.42 | +42.011 | 93% | 0.13 | 0.94 |
| Met1 sulfoxide (+16 Da) | -0.36 | +15.995 | 93% | 0.21 | 1.51 |
| diketopiperazine (−18 Da) | +0.16 | -18.011 | 91% | 0.18 | 1.26 |
des-Met (−131 Da)
- Retention offset from the main peak
- +0.20 min on RG-2
- Mass difference
- -131.040 Da
- Reported in
- 150 of 160 records (94 %)
- Level when reported
- median 0.09 %, max 0.91 %
- Resolution requirement
- Close-eluting — resolution below 1.2 is common and the peaks merge on short gradients.
N-acetyl semax (+42 Da)
- Retention offset from the main peak
- +0.42 min on RG-2
- Mass difference
- +42.011 Da
- Reported in
- 149 of 160 records (93 %)
- Level when reported
- median 0.13 %, max 0.94 %
- Resolution requirement
- Baseline-resolved on the reference method.
Met1 sulfoxide (+16 Da)
- Retention offset from the main peak
- -0.36 min on RG-2
- Mass difference
- +15.995 Da
- Reported in
- 148 of 160 records (93 %)
- Level when reported
- median 0.21 %, max 1.51 %
- Resolution requirement
- Baseline-resolved on the reference method.
diketopiperazine (−18 Da)
- Retention offset from the main peak
- +0.16 min on RG-2
- Mass difference
- -18.011 Da
- Reported in
- 146 of 160 records (91 %)
- Level when reported
- median 0.18 %, max 1.26 %
- Resolution requirement
- Close-eluting — resolution below 1.2 is common and the peaks merge on short gradients.
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.
- Met1 oxidation — an N-terminal methionine on a hygroscopic cake is a bad combination
- diketopiperazine formation