DIRECT COUPLING OF ION CHROMATOGRAPHY WITH SUPPRESSED CONDUCTOMETRIC CAPILLARY ELECTROPHORESIS

Two approaches to interfacing a suppressed ion chromatography (IC) sys tem with a suppressed conductometric capillary electrophoresis (CE) se paration system are described. The first interface uses a six-port loo p valve which allows selective introduction of any segment of an IC el uite band into the CE system. This arrangement is also suitable as a s ample delivery system, especially with CE systems using relatively sho rt capillaries and high electric fields. In the second interface, a sm all fraction of the IC effluent passes through a length of Nafion tube immersed in a solution of saturated Na2B4O7. Thus, sufficient borax i s introduced by Donnan penetration to increase the ionic strength of t he flowing stream to an extent appropriate for carrying out CE separat ions. This valveless design allows the continuous injection of all IC eluite bands into the CE system without additional electrolyte prepara tion for CE. (C) 1997 John Wiley & Sons, Inc.