This paper reviews recent 5-years application researches using online sample preconcentration (OSP) methods in capillary electrophoresis (CE) coupled with mass spectrometry (MS). CE-MS has excellent analytical features such as high-resolution separation, rapid analysis time, low sample consumption, and small consumption of organic solvents. Recently, low flow-rate interface for electrospray ionization has been developed and zmol-level sensitivity has been achieved. However, application of CE-MS has still been prevented due to small capacity of sample injection volume. OSP methods have been developed to address this issue and up to 5,000-fold sensitivity improvement was obtained so far. Various application has been carried out such as proteomics, metabolomics, and glycomics, and CE-MS attracts much attention as the highest-performance analytical tool for small-volume bioanalysis. Taking account of further progress in CE-MS, smart and practical application of OSP methods will be more important in various analytical fields.
2017 The Society for Chromatographic Sciences