Separation window dependent multiple injection (SWDMI) for large scale analysis of therapeutic antibody N-glycans

There is a growing demand in the biopharmaceutical industry for large scale N-glycosylation analysis of biotherapeutics, especially monoclonal antibodies. To fulfill this high throughput analysis requirement with single column separation systems in most instances require finishing the entire analysis cycle including conditioning, injection and separation between sample injections. While in liquid chromatography it represents a challenge, multiple sample injection in capillary electrophoresis has already been demonstrated for one or two sample components by utilizing the concept of introducing sequential sample and buffer zones into the capillary tubing before the start of the separation process. It was also demonstrated in CE-MS mode, mostly to follow one sample component, identified by precise mass measurement. Here we introduce a novel multiple injection approach for rapid large scale capillary electrophoresis analysis of samples with biopharmaceutical interest supporting multicomponent optical detection with laser induced fluorescence. In Separation Window Dependent Multiple Injection (SWDMI) mode, the samples are consecutively injected in predefined time intervals, based on the window that covers the separation of all sample components. As a practical example, this newly developed SWDMI protocol was applied to rapid and large scale analysis of APTS labeled monoclonal antibody N-glycans using a short (20cm effective length) capillary column. Full analysis of 96 samples (injected from a well plate) was obtained in 4h, in contrast to consecutive individual separation cycle processing of the same samples that required 12h.