[Progress in techniques of interfacing capillary electrophoresis with inductively coupled plasma mass spectrometry]

The coupling of capillary electrophoresis (CE) with inductively coupled plasma mass spectrometry (ICP-MS) has demonstrated multiple advantages, including high separation efficiency, sensitivity and resolution, as well as low sample consumption and detection limit. The technique has been widely used for the speciation of environmental and biological samples. The interface between CE and the nebulizing system of ICP-MS plays a key role in the hyphenation of CE and ICP-MS. The most important factors in the interface design were reviewed in this paper, including electrical connections, nebulizer designs and flow compensation in the nebulizer system. Methods for achieving stable electrical current within the capillary were discussed, including the employment of concentric sheath flow, stainless steel components, platinum wire and silver paint. The structures and performance of various nebulizer designs were reviewed and compared, including the concentric pneumatic nebulizer (CPN), micro concentric nebulizer (MCN), high efficiency nebulizer (HEN), ultrasonic nebulizer (USN) and direct injection nebulizer (DIN). To eliminate nebulizer suction, four compensations systems were suggested, including applying a negative pressure at the inlet of the capillary, putting a sol-gel frit at the outlet of the capillary, pumping an appropriate make-up flow to the interface and adjusting the height of the make-up flow. 35 papers were cited.