In-line HPLC-ICP-MS method for the rapid speciation and quantification of metal constituents in cell culture media

Abstract

It is well established that the metal content in Chinese hamster ovary (CHO) cell culture media (CCM) greatly affects process productivity and critical quality attributes (CQAs). Metals exist in diverse chemical forms in CCM, which may change during the monoclonal antibody (mAb) production cycle. Naturally, it is postulated that the chemical speciation of these metals affects their uptake and metabolism. While the targeted forms of metals in media are company-specified, their commercial sources, as well as those of the organic media constituents, may result in concentrations and speciation that differ from the intended formulae. Therefore, there is a need for a method to determine the concentration of metals and their chemical forms. Presented here is a methodology to speciate inorganic-versus-ligated metals using high-performance liquid chromatography (HPLC) employing a polypropylene capillary-channeled (C-CP) fiber column with inductively coupled plasma mass spectrometry (ICP-MS) determinations of five target metals (Mn, Fe, Co, Cu, and Zn). A 50 μL injection of CCM supernatant is used for an effective quantification method to identify metal speciation and concentration deviations from reported formula levels. Two case studies as to the utility of the methodology are presented: potential chemical contamination and species variability due to shelf-life. Further development of this method has relevance towards quality control, identification of contaminants, assessment of media stability/degradation products, and measurement of whole cell metal uptake in growth media.