International Journal of Analytical Chemistry

Research Article

A Multidisciplinary Investigation to Determine the Structure and Source of Dimeric Impurities in AMG 517 Drug Substance

Table 5

Mass error analysis of the observed accurate mass for fragments generated by the acid hydrolysis of the enriched impurity fraction. The analysis is conducted for both the thioether and bis-sulfoxide structures proposed for Unknown 2. (ND: not detected; N/A: not applicable.)
Obs. mass (M + H)+ (Da) Calc. mass thioether (M + H)+ (Da) Calc. mass bis-sulfoxide (M + H)+ (Da) Mass error thioether (ppm) Mass error bis- sulfoxide (ppm)
Unknown 2 891.1081891.1060891.12372.417.5
Mono-deacetyl849.0967849.0954849.11321.519.4
Bis-deacetyl807.0874807.0848807.10263.218.8
U2-669 669.0674669.0655669.08322.823.6
Mono-deacetyl627.0552 627.0549627.07270.5 27.9
627.05581.427.0
Bis-deacetyl585.0458585.0443585.06212.627.9
U2-447 447.0250447.0250447.04280.039.8
Mono-deacetyl405.0158 405.0144405.03223.5 40.5
405.01573.240.7
Bis-deacetylND363.0039363.0216N/AN/A
241 241.0579241.0583241.05831.71.7