Simulation and Experimental Study on Doubled-Input Capacitively Coupled Contactless Conductivity Detection of Capillary Electrophoresis

In this contribution, we optimize the structure of double-input capacitively coupled contactless conductivity detector (DIC(4)D) that proposed before by our group and successfully applied it in the capillary electrophoresis of inorganic ion analysis. Furthermore, we present the detail theoretical analysis and simulation to exploring the working mechanism of DIC(4)D. Compared with C(4)D, under identical experimental conditions and by using the same current-to-voltage converter, both the theoretical and experimental results suggest that the effectiveness and feasibility of DIC(4)D. The improved DIC(4)D diminished the baseline drift effects in C(4)D, provides lower noise, higher sensitivity and notably stable baseline. The LODs of DIC(4)D are 1.0 μM for K(+) and 1.5 μM for Li(+) (S/N = 3). DIC(4)D provides a better linear relationship (R = 0.997 and 0.998 for K(+) and Li(+), respectively) with the range of 2.0 μM ~ 2.5 mM.