Potential and limitations of capillary electrophoresis inductively coupledplasma mass spectrometry - Invited lecture

The hyphenation interface of CE to ICP-MS was characterised with respect to capillary position, gas flow rates and positioning of the total interface to the ICP-MS system. It turned out that absolutely optimised and reproduci ble operation is possible when all variable parameters are adjustable by mi crometer screws. Analysis of a laboratory reference sample gave identical r esults (detection limit, element concentration, time of detection) after ea ch set-up of the system during several years. After optimising the interfac e, the potential of the hyphenated system was elucidated. The hyphenated sy stem was characterised by high separation capabilities, low detection limit s and a broad field of application. Here, application was extended especial ly to iodine speciation. Detection limits of 0.04-1.2 mu g L-1, depending o n the specific iodine species, were achieved. As the operation of the hyphe nated system was totally reproducible according to micrometer screw drives, possible problems were found to be not typically 'hyphenation problems', b ut problems of capillary interactions and distorted separation. Wrong CE co nditions were demonstrated to result in sample sticking to the capillary wa ll, lack of separation/focusing or decreased species stability. These probl ems were demonstrated by means of Sb speciation.