Nano Capacitively Coupled Contactless Conductivity Detection for Microchip Electrophoresis
K. Ansari Mahabadi, I. Rodriguez, L. Hong, P.C. Hauser, N.F. de Rooij
Agency for Science, Technology and Research, SG
Keywords: conductivity sensor
Abstract:A new Capacitively Coupled Contactless Conductivity Detection (C4D) device with enhanced detection limit down to less than ppb level has been developed and tested. The idea is to decrease the size of the channel section at the detection cell of the electrophoretic C4D chip. The narrowed-down channel with high resistance squeezes the incoming plug of ions resulting to a higher change of the resistance which means higher change in the pickup signal level. The channels were typically from submicron size down to nano-scale located between the excitation and pickup electrodes at the detection cell where the squeezed plug occupies the entire cell resulting to enhanced sensitivity and detection limit. The developed system was applied to the analysis of ions in drinking water samples.