The development of a counterflow-assisted preconcentration technique in capillary electrophoresis electrospray- ionization mass spectrometry

作者：Wang Che Wei; Her Guor Rong^*

来源：Electrophoresis, 2014, 35(9): 1251-1258.

DOI：10.1002/elps.201300446

• CE-MS
• Counterflow
• Poly(dimethylsiloxane)
• Preconcentration
• Sheathless

A preconcentration approach for CE-MS using counterflow-assisted electrokinetic injection was proposed. The proposed preconcentration method was based on a counterflow-compatible sheathless interface. The interface was fabricated using a capillary-assembled PDMS microdevice that allowed the application of a counterflow and provided liquid-film electrical conduction. During electrokinetic injection, a hydrodynamic counterflow was introduced into the separation capillary to retard the movement of the stacking boundary to the CE outlet. Accordingly, a long injection time was achieved without a loss of CE separation. With the use of reverse polarity mode and a dynamic polybrene-coated separation capillary (filled with a 1% formic acid solution), a counterflow-assisted electrokinetic injection of peptide samples (in a aqueous solution containing 1% ammonia and 50% methanol) for 10 min provided a sensitivity enhancement of 750-1480 and a detection limit of 20 pM for the five peptide standards. The proposed technique was applied to the analysis of low nanomolar concentrations myoglobin tryptic peptides.

• 出版日期2014-5