Contactless Conductivity Detection for Capillary Electrophoresis

Capillary electrophoresis is a versatile analysis method for ions based on their differential migration in the electric field. However, the conventional optical detectors are not well suited for all possible analytes. Conductivity detection, in contrast, allows the sensitive quantification of all ions, inorganic or organic, but had been difficult to implement due to the small capillary dimensions. Only the modern form of contactless conductivity detection has enabled wider use of this detection technique.


An ac-signal is coupled into and out of the separation capillary by using a pair of tubular electrodes.



The detector cell built in our laboratory showing the two tubular electrodes and the pick-up amplifier.



Commercial version of the cell now available from eDAQ (www.edaq.com).




The cell together with the accompanying data-acquisition system (www.edaq.com).




Detection of trace levels of perchlorate in a natural water sample.