title: An automated electrokinetic continuous sample introduction system for microfluidic chip-based capillary electrophoresis.
abstract: An automated and continuous sample introduction system for microfluidic chip-based capillary electrophoresis (CE) was developed in this work. An efficient world-to-chip interface for chip-based CE separation was produced by horizontally connecting a Z-shaped fused silica capillary sampling probe to the sample loading channel of a crossed-channel chip. The sample presentation system was composed of an array of bottom-slotted sample vials filled alternately with samples and working electrolyte, horizontally positioned on a programmable linearly moving platform. On moving the array from one vial to the next, and scanning the probe, which was fixed with a platinum electrode on its tip, through the slots of the vials, a series of samples, each followed by a flow of working electrolyte was continuously introduced electrokinetically from the off-chip vials into the sample loading channel of the chip. The performance of the system was demonstrated in the separation and determination of FITC-labeled arginine and phenylalanine with LIF detection, by continuously introducing a train of different samples. Employing 4.5 kV sampling voltage (1000 V cm(-1) field strength) for 30 s and 1.8 kV separation voltage (400 V cm(-1) field strength) for 70 s, throughputs of 36 h(-1) were achieved with <1.0% carryover and 4.6, 3.2 and 4.0% RSD for arginine, FITC and phenylalanine, respectively (n = 11). Net sample consumption was only 240 nL for each sample.
authors.affiliation: Institute of Microanalytical Systems, Chemistry Department, Zhejiang University, Hangzhou 310028, China.
authors.forename: Qiao-Hong
authors.initials: QH
authors.lastname: He
authors.forename: Qun
authors.initials: Q
authors.lastname: Fang
authors.forename: Wen-Bin
authors.initials: WB
authors.lastname: Du
authors.forename: Yan-Zhen
authors.initials: YZ
authors.lastname: Huang
authors.forename: Zhao-Lun
authors.initials: ZL
authors.lastname: Fang
mesh_terms: D019075:Electrophoresis, Capillary / Q000295:instrumentation* / Q000379:methods; D008832:Microchemistry; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods