[Concentration techniques in capillary electrophoresis analysis and their applications]

Capillary electrophoresis (CE), as a modern analytical technique, has been successfully applied in the analysis of metal ions, organics, proteins, nucleic acids and cells, due to its short analysis time, high separation efficiency, low sample consumption and low cost. Since most commercial CE instruments are equipped with ultraviolet detectors (UV) , the application of CE-UV with low sensitivity owing to limited optical pathway of on-capillary photometry and the small sample injection volume, is strictly limited in real sample analysis. On-column preconcentration technique is an efficient approach to greatly improve the sensitivity of CE-UV, which can be achieved by merely adjusting the parameters, without any modification of the instrument. At present, stacking, dynamic pH junction, sweeping and transient isotachophoresis are the commonly used on-column preconcentration techniques in CE analysis, and have been extensively utilized in food science, environmental science and biomedicine fields. On the other hand, for real sample analysis, proper sample pretreatment is often necessary prior to instrumental analysis, aiming to remove sample matrix and enrich target analytes simultaneously. With the development tendency of economy, miniaturization and automation in modern analytical methods, green and miniaturized sample pretreatment techniques such as solid phase microextraction (SPME) and liquid phase microextraction (LPME) have been developed rapidly in recent decades. The combination of miniaturized sample pretreatment techniques and CE on-column preconcentration techniques can provide a promising method for the determination of trace analytes in complicated real samples.