Electrolyte systems for on-line CE-MS: Detection requirements and separation possibilities

In contemporary analytical practice, the on-line CE-MS technique has established as a powerful separation and identification analytical tool. Its major instrumental aspects can be considered as solved and its routine use with specific applications to be implemented is the typical task at present. In that context, the chemical (wet, electrophoretic) part of the technique becomes very important as here the separation battle of the overall success of the developed method is fought. The review brings an overview of the electrolyte systems used in the CE part of the CE-MS technique together with a detailed insight into their pros and cons from the electrophoretist's viewpoint. Advanced electrophoretic approaches including sample stacking, ITP and use of non-aqueous solvents are also discussed. An overview of the electrolyte systems used in over 200 selected applications is given, sorted according to the analytes of interest.