| Capacitively coupled contactless conductivity detection (C4D) is universal for CE in that all charged species can be quantified, and it is particularly attractive for those inorganic and organic ions that are not directly accessible by optical means. Capacitively coupled contactless conductivity detection is widely adopted in capillary electrophoresis. It has been applied in the determination of inorganic ions, organic ions and biochemicals. In this article, a capacitively coupled contactless conductivity detector was designed. The performances of the detector have been demonstrated. Several compounds were determined with C4D.1. Based on principle introduced by Zemann et al., we designed a capacitively coupled contactless conductivity detector for capillary electrophoresis. It consists of an external ac voltage source for excitation, a detector cell and a detector circuitry for processing the cell current. The baseline noise was effectively decreased by optimization of the detector circuitry. The overall stabilities of C4D were investigated by experiment.2. The separation of three saccharides has been investigated by CE and C4D. The electrophoretic conditions were optimized with the running buffer of 15 mM NaOH,5 mM Na2HPO4 and 200μM CTAB, and the applied voltage of-22 kV over a capillary of 50μm i.d.×53 cm (43 cm to the detector window). Under the optimal conditions, three saccharides were baseline separated within 10 min. This method can be used for the determination of saccharides in soft drink.3. Six phenolic acids were separated and determined by CE with C4D detection. The electrophoretic conditions were optimized with the running buffer of 150 mmol/L 2-Amino-2-methyl-1-propanol(AMP), and the applied voltage of+22 kV over a capillary of 50μm i.d.×50 cm(40 cm to the detector window). Under the optimal conditions, three saccharides were baseline separated within 5 min. The detection limits for them were between 5.0μg/L and 10.0μg/L,...
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