Referenced Capacitively Coupled Conductivity Detector for Capillary Electrophoresis

Abstract

A dual capacitively coupled contactless conductivity detector for capillary electrophoresis was developed. The two channels are arranged in a bridge configuration so that one of them acts as a reference whose signal is subtracted. This effectively compensates for the baseline conductivity of the separation buffer so that the electronic zero setting is not necessary. Changes in the buffer composition are automatically accounted for, as are temperature drifts. The system is demonstrated for the detection of inorganic model cations in capillary electrophoresis. Besides the use with two separate capillaries, one of which solely serves as reference, it was also found possible to use a single capillary which is looped back through the reference cell.

Contactless conductivity detection for analytical techniques—Developments from 2012 to 2014

“…The referenced system reported by Stojkovic et al. consisted of a single cell through which the detection end of the capillary was looped back. Both approaches automatically subtract the background signal and can thus compensate for baseline drifts due to temperature and other reasons.…”

Authenticity screening of seized whiskey samples using electrophoresis microchips coupled with contactless conductivity detection

“…The bridge configuration effectively causes the effect of the stray capacitance to be cancelled. In addition, a grounded shield separates the excitation electrodes and the detection electrodes to reduce the effects of surface conduction . The four circular points depicted in Fig.…”

Simultaneous determination of rare earth elements in ore and anti-corrosion coating samples using a portable capillary electrophoresis instrument with contactless conductivity detection

“…The high voltage (HV) end of the capillary was isolated in a safety cage equipped with a microswitch to interrupt the HV when the lid was opened. Detection was carried out with a miniaturized C 4 D cell built in-house [50,51]. The resulting signals were recorded with an ADC-20 data acquisition system (Pico Technology, St. Neots, UK) which was connected to the USBport of a personal computer.…”