TB-500 impurity profile
Every named species the index has reported alongside TB-500, 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
0.47%
n=268
Median largest single
0.23%
n=268
Worst single observed
1.48%
n=268
Named species observed
4 / 4
n=4
| Named species | ΔRT (min) | Δ mass (Da) | Seen in | Median % area | Max % area |
|---|---|---|---|---|---|
| des-acetyl TB-500 (−42 Da) | -0.52 | -42.011 | 91% | 0.11 | 0.79 |
| des-Gln truncate (−128 Da) | -0.24 | -128.059 | 90% | 0.09 | 1.48 |
| C-terminal amide (−1 Da) | +0.18 | -0.984 | 86% | 0.08 | 1.35 |
| [D-Thr]-diastereomer | -0.11 | mass-identical | 85% | 0.08 | 1.16 |
des-acetyl TB-500 (−42 Da)
- Retention offset from the main peak
- -0.52 min on RG-2
- Mass difference
- -42.011 Da
- Reported in
- 244 of 268 records (91 %)
- Level when reported
- median 0.11 %, max 0.79 %
- How it separates
- Baseline-resolved on the reference method.
des-Gln truncate (−128 Da)
- Retention offset from the main peak
- -0.24 min on RG-2
- Mass difference
- -128.059 Da
- Reported in
- 240 of 268 records (90 %)
- Level when reported
- median 0.09 %, max 1.48 %
- 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.
C-terminal amide (−1 Da)
- Retention offset from the main peak
- +0.18 min on RG-2
- Mass difference
- -0.984 Da
- Reported in
- 230 of 268 records (86 %)
- Level when reported
- median 0.08 %, max 1.35 %
- 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.
[D-Thr]-diastereomer
- Retention offset from the main peak
- -0.11 min on RG-2
- Mass difference
- mass-identical — chromatography only
- Reported in
- 228 of 268 records (85 %)
- Level when reported
- median 0.08 %, max 1.16 %
- 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.
- acetyl loss under acidic hydrolysis
- no oxidative liability