Table 2. Summary of immunoconjugate peaks observed by ESI-MS.

Assignment	m/z a
Trastuzumab
Light chain	23 439
Heavy chain	50 594 (50 757)
Light-heavy chain	74 031 (74 194)
H3YM103-trastzumab
Light chain	23 439
Light chain + H3YM103	24 360
Heavy chain	50 594 (50 755)
Heavy chain + H3YM103	51 519 (51 676)
Heavy chain + 2(H3YM103)	52 439 (52 596)
Heavy chain + 3(H3YM103)	53 356 (53 518)
Light-heavy chain	74 031 (74 194)
Light-heavy chain + H3YM103	74 954 (75 118)
Light-heavy chain + 2(H3YM103)	75 877 (76 038)
H3DFO-trastuzumab
Light chain + 1(H3DFO)	24 151
Heavy chain + 3(H3DFO)	52 730 (52 892)
Light-heavy chain + 2(H3DFO)	75 466 (75 617)

^a Signal in brackets due to additional hexose unit in variably glycosylated heavy chain.