Characterization of dissolved organic carbon at low levels in environmental waters by microfluidic-chip-based capillary gel electrophoresis with a laser-induced fluorescence detector.

A microfluidic analytical system for characterization of dissolved organic carbon (DOC) in environmental waters, based on a capillary gel electrophoresis (CGE) device with a laser-induced fluorescence (LEF) detector, was developed. The applied voltage and the running buffer were investigated to control the simple floating injection and CGE separation for convenient cross-type microchips made from polymethyl-methacylate. We obtained reproducible peaks for standard organic solutions and the determination time is less than 70 s. The values of the relative standard deviation (RSD) were 0.17-2.01% for repetitive injection (n = 12). We demonstrated high-throughput characterization of DOC in environmental water from the Biwa Lake and the Hino River using microfluidic chip and determined that the content of DOC in the Biwa Lake changed with the seasons.