On-line isotachophoretic preconcentration and gel electrophoretic separation of sodium dodecyl sulfate-proteins on a microchip

• Published in: Electrophoresis 2005-06, Vol.26 (11), p.2254-2260
• Main Authors: Huang, Huaiqing, Xu, Feng, Dai, Zhongpeng, Lin, Bingcheng
• Format: Article
• Language: English
• Subjects: Calibration; Electrophoresis, Microchip - instrumentation; Electrophoresis, Microchip - methods; Equipment Design; Gel electrophoresis; Isotachophoresis; Miniaturization; On-line preconcentration; Online Systems; Proteins - isolation & purification; Sodium Dodecyl Sulfate; Sodium dodecyl sulfate-proteins
• ISSN: 0173-0835; 1522-2683
• DOI: 10.1002/elps.200410393

A microchip for integrated isotachophoretic (ITP) preconcentration with gel electrophoretic (GE) separation to decrease the detectable concentration of sodium dodecyl sulfate (SDS)‐proteins was developed. Each channel of the chip was designed with a long sample injection channel to increase the sample loading and allow stacking the sample into a narrow zone using discontinuous ITP buffers. The preconcentrated sample was separated in GE mode in sieving polymer solutions. All the analysis steps including injection, preconcentration, and separation of the ITP‐GE process were performed continuously, controlled by a high‐voltage power source with sequential voltage switching between the analysis steps. Without deteriorating the peak resolution, four SDS‐protein analyses with integrated ITP‐GE system resulted in a decreased detectable concentration of ∼40‐fold compared to the GE mode only. A good calibration curve for molecular weights of SDS‐proteins indicated that the integrated ITP‐GE system can be used for qualitative analysis of unknown protein samples.