title: Double-cross hydrostatic pressure sample injection for chip CE: variable sample plug volume and minimum number of electrodes.
abstract: A novel sample injection method for chip CE was presented. This injection method uses hydrostatic pressure, generated by emptying the sample waste reservoir, for sample loading and electrokinetic force for dispensing. The injection was performed on a double-cross microchip. One cross, created by the sample and separation channels, is used for formation of a sample plug. Another cross, formed by the sample and controlling channels, is used for plug control. By varying the electric field in the controlling channel, the sample plug volume can be linearly adjusted. Hydrostatic pressure takes advantage of its ease of generation on a microfluidic chip, without any electrode or external pressure pump, thus allowing a sample injection with a minimum number of electrodes. The potential of this injection method was demonstrated by a four-separation-channel chip CE system. In this system, parallel sample separation can be achieved with only two electrodes, which is otherwise impossible with conventional injection methods. Hydrostatic pressure maintains the sample composition during the sample loading, allowing the injection to be free of injection bias.
authors.affiliation: Laboratory of Microfluidics for Systems Biology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian, Liaoning Province, P.R. China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Luo
authors.forename: Dapeng
authors.initials: D
authors.lastname: Wu
authors.forename: Shaojiang
authors.initials: S
authors.lastname: Zeng
authors.forename: Hongwei
authors.initials: H
authors.lastname: Gai
authors.forename: Zhicheng
authors.initials: Z
authors.lastname: Long
authors.forename: Zheng
authors.initials: Z
authors.lastname: Shen
authors.forename: Zhongpeng
authors.initials: Z
authors.lastname: Dai
authors.forename: Jianhua
authors.initials: J
authors.lastname: Qin
authors.forename: Bingcheng
authors.initials: B
authors.lastname: Lin
mesh_terms: D004566:Electrodes; D019075:Electrophoresis, Capillary / Q000295:instrumentation* / Q000379:methods*; D006874:Hydrostatic Pressure; D007700:Kinetics; D056656:Lab-On-A-Chip Devices; D046208:Microchip Analytical Procedures / Q000379:methods*