Table 3. Quantification of purified lots of mAb2 by RP-UPLC.

Lot	Process intermediate	Reported color	Conc. (g/L)	RP HPLC B12 (ppm)	ng B12/mg Protein1
Lot 1	Protein A Pool	Strongly pink	12.8	1.49	116.4
Lot 2	Protein A Pool	Pink	12.2	0.81	66.7
	Column 2 Pool	Colorless	6.5	0.25	39.2
	Column 3 Pool	Pink	12.6	0.49	39.2
	DS	Pink	21.9	0.88	40.4
Lot 3	Protein A Pool	Colorless	21.6	0.18	8.3
	Column 2 Pool	Colorless	11.9	0.06	5.1
	Column 3 Pool	Colorless	9.4	0.05	5.8

¹ Assuming a molecular weight of 150 kD for mAbs, a conversion factor of 11 070 may be used to obtain B₁₂-Protein molar ratio.