AssayIndex
Cross-section

Melanotan II impurity profile

Every named species the index has reported alongside Melanotan II, 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.

77 recordsmedian 99.42 %spec 98.5 %
Median total impurities 0.58% n=77
Median largest single 0.29% n=77
Worst single observed 1.55% n=77
Named species observed 5 / 5 n=5
Named speciesΔRT (min)Δ mass (Da)Seen inMedian % areaMax % area
linear (open-lactam) precursor (+18 Da)-0.74+18.01191%0.170.99
des-acetyl MT-II (−42 Da)-0.48-42.01188%0.080.45
oxidised Trp (+16 Da)-0.36+15.99579%0.081.55
[L-Phe7]-diastereomer-0.16mass-identical78%0.050.64
MT-II dimer (head-to-tail)+2.35+1023.54064%0.060.74

linear (open-lactam) precursor (+18 Da)

Retention offset from the main peak
-0.74 min on RG-2
Mass difference
+18.011 Da
Reported in
70 of 77 records (91 %)
Level when reported
median 0.17 %, max 0.99 %
How it separates
Baseline-resolved on the reference method.

des-acetyl MT-II (−42 Da)

Retention offset from the main peak
-0.48 min on RG-2
Mass difference
-42.011 Da
Reported in
68 of 77 records (88 %)
Level when reported
median 0.08 %, max 0.45 %
How it separates
Baseline-resolved on the reference method.

oxidised Trp (+16 Da)

Retention offset from the main peak
-0.36 min on RG-2
Mass difference
+15.995 Da
Reported in
61 of 77 records (79 %)
Level when reported
median 0.08 %, max 1.55 %
How it separates
Baseline-resolved on the reference method.

[L-Phe7]-diastereomer

Retention offset from the main peak
-0.16 min on RG-2
Mass difference
mass-identical — chromatography only
Reported in
60 of 77 records (78 %)
Level when reported
median 0.05 %, max 0.64 %
How it separates
Chromatography only. A gradient long enough to separate it; no mass spectrometer of any resolution will.

MT-II dimer (head-to-tail)

Retention offset from the main peak
+2.35 min on RG-2
Mass difference
+1023.540 Da
Reported in
49 of 77 records (64 %)
Level when reported
median 0.06 %, max 0.74 %
How it separates
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.

  • Trp oxidation
  • lactam hydrolysis reopening the ring