Therapeutic monoclonal antibodies (mAbs) are complex glycoproteins and ensuring their safety, efficacy and quality is still challenging. Indeed, during their manufacturing process, they are exposed to several stresses that can lead to their denaturation, misfolding or dimerization. We report here a new method based on capillary electrophoresis coupled to native mass spectrometry (MS) with a sheath liquid interface to analyze an intact therapeutic mAb, Infliximab, under non-denaturing conditions that preserve its conformational heterogeneity as well as self-association without inducing further unfolding / denaturation. For capillary zone electrophoresis (CZE) separation, a triple layer coating using polybrene-dextran sulfate-polybrene was employed. A sheath liquid composed of isopropanol - water - acetic acid with a flow rate of 10 μL min