Automatic Protein Separation by Microchip Electrophoresis Using Quartz Chip

Electrophoretic separation techniques using microchips have been dramatically improved and several commercial MCE systems have been developed. For example, the Agilent Technologies 2100 Bioanalyzer system is commercially available with a protein separation chip and reagent kit that enables rapid and highly efficient protein separation based on their molecular size [1]. Separation of protein mixtures in ten samples can be achieved in approximately 30 minutes using the disposable 10−sample separation glass microchip. For more numerous samples or automatic separations, however, the chip must be replaced for each set of 10 samples. In contrast, Shimadzu Corporation has developed the MCE−2010 system based on a quartz microchip, which is capable of sequential and automatic analyses [2]. Once the samples are set and programmed, 96 sequential samples can be processed without further handling. Two types of detection methods (UV and LIF) are available in models of MCE 2010 and MCE 2010 LIF, respectively. DNA analysis can be performed using either UV or LIF [3], amino sugar analysis can use LIF [4], and analysis of monosaccharide derivatives can be performed using UV detection [5]. Since the detectability of proteins in UV detection is 10−100 times lower than that in LIF detection, on−line sample preconcentration on single channel [6] or cross channel [7] techniques were developed and applied to higher sensitive detection of low concentration protein mixtures that are not detectable with UV methods. In this report, we describe the optimization of size−based protein separation on Original