Interface for capillary electrophoresis coupled with inductively coupled plasma atomic emission spectrometry

A modified concentric nebulizer was used as the interface to couple capilla ry electrophoresis (CE) to inductively coupled plasma atomic emission spect rometry (ICP-AES). The CE capillary replaces the central tube of the concen tric nebulizer. The tip of the nebulizer tapers slowly to allow uncertainty in the position of the capillary. A platinum wire was inserted into the CE capillary to provide electrical connection to the CE power supply. pH chan ges inside the capillary due to electrolysis of the background buffer elect rolyte was small and has minimal effects on the CE separation. The peak bro adening effects due to the nebulizing gas flow, however, were significant. Resolution decreases quickly when the flow-rate of the carrier gas increase s. Sample stacking technique was used to improve the resolution of species of opposite charge, e.g., Cr(VI) vs. Cr(III) ions. Detection limit of Cr ba sed on peak area is similar to 10 ppb for the CE-ICP-AES system. (C) 1999 E lsevier Science B.V. All rights reserved.