Poloxamer 188 10 solution

Phosphoric acid 85% solution, tris(hydroxymethyl) aminomethane (Tris), T‐EthA, TEA, poloxamer 188 10% solution, PB, DXS, dimethylsulfoxide (DMSO) and Protein A agarose were obtained from Merck/Sigma‐Aldrich (Darmstadt, Germany). HyClone ActiPro medium was purchased from Cytiva (Marlborough, USA). Three commercially available mAbs were purchased, NIST mAb reference material (NIST) (10 mg/ml in 12.5 mM l‐histidine, 12 mM l‐histidine HCl) and SILuLite SigmaMAb Rituximab mAb were from Sigma‐Aldrich (Darmstadt, Germany), and Intact mAb Mass Check Standard was from Waters (Milford, USA), hereafter referred to as NIST mAb, Rituximab and Waters mAb. For method validation, adalimumab (10 mg/ml in 12.5 mM histidine buffer) was purchased from Merck/Sigma‐Aldrich (Darmstadt, Germany). Spent cell‐culture medium samples of process A after 6, 10 or 14 days of cultivation and purified drug substance (DS) samples were provided by Byondis BV, Nijmegen, the Netherlands. Spent cell‐culture medium samples of process B after 0, 5 or 8 days of cultivation and process C after 0 or 7 days of cultivation were provided by the Department of Industrial Biotechnology, KTH Royal Institute of Technology, Stockholm, Sweden. All chemicals were of analytical grade, water was of Milli‐Q grade (18.2 MΩ cm).