AssayIndex
Cross-section

Retatrutide impurity profile

Every named species the index has reported alongside Retatrutide, 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.

496 recordsmedian 98.41 %spec 96.5 %
Median total impurities 1.59% n=496
Median largest single 0.85% n=496
Worst single observed 2.76% n=496
Named species observed 8 / 8 n=8
Named speciesΔRT (min)Δ mass (Da)Seen inMedian % areaMax % area
[D-Aib2]-diastereomer-0.22mass-identical92%0.212.26
des-Aib20 analogue-0.44-85.05380%0.201.63
C18 diacid regioisomer+0.58mass-identical77%0.132.38
truncated (5-39)-1.92-428.20173%0.142.76
oxidised Trp (+16 Da)-0.66+15.99573%0.081.91
aspartimide (−18 Da)+0.71-18.01162%0.101.65
incomplete Fmoc removal (+222 Da)+2.41+222.06862%0.102.22
retatrutide dimer+4.12+4728.48741%0.071.53

[D-Aib2]-diastereomer

Retention offset from the main peak
-0.22 min on RG-2
Mass difference
mass-identical — chromatography only
Reported in
456 of 496 records (92 %)
Level when reported
median 0.21 %, max 2.26 %
Resolution requirement
A gradient long enough to separate it. No mass spectrometer will.

des-Aib20 analogue

Retention offset from the main peak
-0.44 min on RG-2
Mass difference
-85.053 Da
Reported in
399 of 496 records (80 %)
Level when reported
median 0.20 %, max 1.63 %
Resolution requirement
Baseline-resolved on the reference method.

C18 diacid regioisomer

Retention offset from the main peak
+0.58 min on RG-2
Mass difference
mass-identical — chromatography only
Reported in
383 of 496 records (77 %)
Level when reported
median 0.13 %, max 2.38 %
Resolution requirement
A gradient long enough to separate it. No mass spectrometer will.

truncated (5-39)

Retention offset from the main peak
-1.92 min on RG-2
Mass difference
-428.201 Da
Reported in
361 of 496 records (73 %)
Level when reported
median 0.14 %, max 2.76 %
Resolution requirement
Baseline-resolved on the reference method.

oxidised Trp (+16 Da)

Retention offset from the main peak
-0.66 min on RG-2
Mass difference
+15.995 Da
Reported in
361 of 496 records (73 %)
Level when reported
median 0.08 %, max 1.91 %
Resolution requirement
Baseline-resolved on the reference method.

aspartimide (−18 Da)

Retention offset from the main peak
+0.71 min on RG-2
Mass difference
-18.011 Da
Reported in
308 of 496 records (62 %)
Level when reported
median 0.10 %, max 1.65 %
Resolution requirement
Baseline-resolved on the reference method.

incomplete Fmoc removal (+222 Da)

Retention offset from the main peak
+2.41 min on RG-2
Mass difference
+222.068 Da
Reported in
306 of 496 records (62 %)
Level when reported
median 0.10 %, max 2.22 %
Resolution requirement
Baseline-resolved on the reference method.

retatrutide dimer

Retention offset from the main peak
+4.12 min on RG-2
Mass difference
+4728.487 Da
Reported in
202 of 496 records (41 %)
Level when reported
median 0.07 %, max 1.53 %
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.

  • aspartimide formation and subsequent β-Asp isomerisation at Asp-Ser
  • Trp oxidation under fluorescent light in clear glass
  • aggregation above 2 mg/mL on freeze–thaw