title: A simplified poly(dimethylsiloxane) capillary electrophoresis microchip integrated with a low-noise contactless conductivity detector.
abstract: A contactless conductivity detector integrated into a poly(dimethylsiloxane) microchip for electrophoresis is presented. It adopted the simplest configuration of electrodes commonly used in this detection mode for capillary electrophoresis microchips. Although the chip is based on a simple and effective design, it is able to obtain low detection levels due to the low noise of the detection circuit. A circuit based on a lock-in amplifier was designed on printed circuit boards to read out the signal. The property of the detection cell was studied by applying excitation signals of different frequencies and different amplitudes. It was found that the best detection limit could be achieved with a frequency of 50 kHz and amplitude of 20 V. The performance of the detector was demonstrated by successfully separating and detecting several inorganic ions and also a mixture of heavy metal ions. An average detection limit of 0.4 μM was obtained for inorganic cations. This value is significantly improved compared to similar microchip-based detectors. The presented detector could be promising for mass production due to its properties, such as simple construction, high degree of integration, high performance and low cost.
authors.affiliation: State Key Lab of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, P. R. China.
authors.forename: Benyan
authors.initials: B
authors.lastname: Liu
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Dirk
authors.initials: D
authors.lastname: Mayer
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Krause
authors.forename: Qinghui
authors.initials: Q
authors.lastname: Jin
authors.forename: Jianlong
authors.initials: J
authors.lastname: Zhao
authors.forename: Andreas
authors.initials: A
authors.lastname: Offenhäusser
mesh_terms: D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D004553:Electric Conductivity; D046209:Electrophoresis, Microchip / Q000295:instrumentation* / Q000379:methods; D019216:Metals, Heavy / Q000032:analysis; D012680:Sensitivity and Specificity
chemical_list: D004129:Dimethylpolysiloxanes; D019216:Metals, Heavy; C013830:baysilon