Abstract:

Sodium dodecyl sulfate capillary electrophoresis has become the mainstream method for purity analysis of monoclonal antibodies because of its advantages of fast and high resolution. Sample preparation has a significant impact on the purity detection of non-reduced monoclonal antibodies. In order to optimize sample preparation, the purity of monoclonal antibodies of different types and batches in sample buffers with iodoacetamide and N-ethyl maleimide as sulfhydryl sealants and at pH 6.0-9.0 was investigated. It was found that in the two types of sulfhydryl sealants, the high pH sample buffer could affect the sealing effect of the sulfhydryl sealant and produce more antibody fragments. Conversely, under the low pH condition, the antibody fragments were fewer and the purities of monoclonal antibodies were higher. Therefore, the sample buffer with pH 6.0 is the optimal preparation condition for the purity detection of non-reduced monoclonal antibodies.

Key words: N-ethylmaleimide (NEM), capillary electrophoresis (CE), iodoacetamide (IAM), monoclonal antibody, non-reduced, sodium dodecyl sulfate (SDS)