[Annual review of capillary electrophoresis technology in 2020]

This paper reviews the developments in capillary electrophoresis (CE) in 2020. A total of 222 research papers related to CE technology published in 2020 were retrieved from the ISI Web of Science. These papers were selected by using the keywords "capillary electrophoresis-mass spectrometry", "capillary isoelectric focusing", "micellar electrokinetic chromatography", or "capillary electrophoresis" as search conditions. A further 37 research papers related to CE technology were found in Chinese journals: Chinese Journal of Analytical Chemistry and Chinese Journal of Chromatography. The 38 papers published in 13 different journals with an impact factor (IF)≥5.0 are individually discussed. In particular, the journal Analytical Chemistry (IF=6.8) was found to have nine relevant articles, eight of which were related to CE-MS technology and its application, while Food Chemistry (IF=6.3) published five articles with four papers based on micellar electrokinetic chromatography (MEKC) and its combined technology. This demonstrated that MEKC can simultaneously separate negatively charged, positively charged, and neutral particles, in addition to featuring the advantage of combining different detector applications for the analysis of target matter in a complex matrix. In Analytica Chimica Acta (IF=6.0), five articles were collected, which mainly focused on new applications of CE-MS and multimode CE research. In Talanta (IF=5.3), 10 articles were collected, which focused on new methods and applications of CE and CE-MS. The remaining nine articles, i. e., seven experimental articles, one review article, and one introduction of scientific research achievements, were published in various other high-impact journals. At the same time, 184 articles were found in 89 journals with IF<5.0. In particular, the Journal of Chromatography A (IF=4.1) and Electrophoresis (IF=3.1) contained intensive reports for CE: 16 and 24 publications in relevant areas. The representative contents of 40 articles published in two journals were introduced comprehensively in this review, including new materials and new applications of MEKC, as well as new applications of CE-MS and CE. An overview of the work in the 37 articles collected from Chinese journals included "Aptamer Special Issue" published by Chinese Journal of Analytical Chemistry and two CE technical special issues published by Chinese Journal of Chromatography. In the "Aptamer Special Issue", Qu Feng's research group from Beijing Institute of Technology reported five works on aptamers based on CE, while the contents of Chinese Journal of Chromatography include new applications of CE and new materials in capillary tubes. In summary, new methods and applications of capillary electrophoresis-mass spectrometry (CE-MS) were the prominent development trend in CE technology in the year 2020, with the main focus being on the combination of CE-MS with electrochemical detection, solid-phase extraction, and various capillary electrophoresis modes. The number of reports related to the CE-MS interface has decreased compared to that in previous years. Conventional CE technology is mainly focused on the applications of MEKC in the analysis and concentration of complex samples, especially for the analysis of complex matrix samples such as food and drugs. In addition, the scientific research achievements of Chinese experts and scholars in CE-related fields cover the application of CE in life sciences, clinical medicine, pharmaceutical research and development, environmental science, natural products, food analysis, etc., representing the level and current status of the application of CE research in China.