Methods and compositions for analyzing host cell proteins

Abstract

Improved sample preparation methods for detecting and/or quantifying host cell proteins in a sample are provided. The methods include contacting a sample with a solid support including an immunoglobulin binding protein at a pH of about 8-10 to produce a sample including the antibody or antibody fragment bound to the solid support. The methods also include contacting the sample including the antibody or antibody fragment bound to the solid support with a protease agent to produce partially digested antibody and target proteins and separating the sample into a first fraction including the antibody or antibody fragment bound to the solid support, and a second fraction including a supernatant including the partially digested target proteins. The methods also include processing the supernatant and detecting the one or more target proteins, for example using mass spectrometry. Compositions and kits for detecting host cell proteins are also provided.

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