A Compact System of Capacitivity Coupled Contactless Conductivity Detection Based on the Square Wave Excitation Signal for Capillary Electrophoresis

摘要

This paper reported a compact system of capacitively coupled contactless conductivity detection (C4D) based on the square wave excitation voltage for capillary electrophoresis, and it exhibited excellent sensitivity at the optimal frequency of 198 kHz. The feasibility and sensitivity of this detector was demonstrated by simultaneous detection of thirteen ions including alkali, alkaline earth and heavy metal ions. And the detection limits (S/N 3) were in the range of 0.2-1 μmol/L for Mn2+, K+, Na+, Mg2+, Ca2+, Li+ , Ba2+, and 7-25 μmol/L for Ni2+, Cu2+, Cd2+, Pb2+, Co2+, Zn2+.