No abstract

Capillary electrophoresis is recognized as a valued separation technique for its high separation efficiency, low sample consumption, good economic and ecological aspects, reproducibility, and complementarity to traditional liquid chromatography techniques. Capillary electrophoresis experiments are generally performed utilizing optical detection, such as ultraviolet or fluorescence detectors. However, in order to provide structural information, capillary electrophoresis hyphenated to highly sensitive and selective mass spectrometry has been developed to overcome the limitations of optical detections. Capillary electrophoresis‐mass spectrometry is increasingly popular in protein analysis, including biopharmaceutical and biomedical research. It is frequently applied for the determination of physicochemical and biochemical parameters of proteins, offers excellent performance for in‐depth characterizations of biopharmaceuticals at various levels of analysis, and has been also already proven as a promising tool in biomarker discovery. In this review, we focus on the possibilities and limitations of capillary electrophoresis‐mass spectrometry for protein analysis at their intact level. Various capillary electrophoresis modes and capillary electrophoresis‐mass spectrometry interfaces, as well as approaches to prevent protein adsorption and to enhance sample loading capacity, are discussed and the recent (2018–March 2023) developments and applications in the field of biopharmaceutical and biomedical analysis are summarized.

Insulin‐like growth factor‐1 (IGF‐1) is a 70‐amino acid single‐chain polypeptide, which has found application in diagnostics as a biomarker of growth hormone disorders and as a therapy for growth failure in children and adolescents. Due to its strong anabolic effects, it is often abused by athletes for doping purposes. Here, we developed an on‐line hyphenated method based on capillary zone electrophoresis (CZE) and triple quadrupole mass spectrometry (MS) detection with electrospray ionization (CZE–electrospray ionization source–MS [CZE–ESI–MS]) for the determination of IGF‐1 in pharmaceutical matrices. We achieved a highly efficient, accurate, repeatable, sensitive, and selective analysis of IGF‐1 with favorable migration times (<15 min). Optimized and validated CZE–ESI–MS method was successfully applied for the determination of IGF‐1 in injectable solutions (Increlex®), and its presence was also confirmed in nutritional preparations (tablets and liquid colostrum). This is the first validated CZE–ESI–MS method for the determination of IGF‐1 in pharmaceutical matrices revealing the potential of capillary electrophoresis for its use in drug quality control laboratories with benefits, such as high separation efficiency, high‐speed analysis, low sample consumption, as well as environmental and cost aspects.