AssayIndex
Cross-section

MGF impurity profile

Every named species the index has reported alongside MGF, 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.

37 recordsmedian 99.29 %spec 97.5 %
Median total impurities 0.71% n=37
Median largest single 0.35% n=37
Worst single observed 1.24% n=37
Named species observed 4 / 4 n=4
Named speciesΔRT (min)Δ mass (Da)Seen inMedian % areaMax % area
aspartimide (−18 Da)+0.32-18.011100%0.170.88
truncated (1-20)-1.22-486.27197%0.210.74
deamidated (+1 Da)-0.24+0.98495%0.171.24
acetyl adduct (+42 Da)+0.40+42.01189%0.140.55

aspartimide (−18 Da)

Retention offset from the main peak
+0.32 min on RG-2
Mass difference
-18.011 Da
Reported in
37 of 37 records (100 %)
Level when reported
median 0.17 %, max 0.88 %
How it separates
Baseline-resolved on the reference method.

truncated (1-20)

Retention offset from the main peak
-1.22 min on RG-2
Mass difference
-486.271 Da
Reported in
36 of 37 records (97 %)
Level when reported
median 0.21 %, max 0.74 %
How it separates
Baseline-resolved on the reference method.

deamidated (+1 Da)

Retention offset from the main peak
-0.24 min on RG-2
Mass difference
+0.984 Da
Reported in
35 of 37 records (95 %)
Level when reported
median 0.17 %, max 1.24 %
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.

acetyl adduct (+42 Da)

Retention offset from the main peak
+0.40 min on RG-2
Mass difference
+42.011 Da
Reported in
33 of 37 records (89 %)
Level when reported
median 0.14 %, max 0.55 %
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.

  • Asn deamidation
  • rapid serum proteolysis (not an assay concern, but the reason PEG-MGF exists)