Simultaneous analysis of seven oligopeptides in microbial fuel cell by micro-fluidic chip with reflux injection mode

► A reflux injection mode was developed for the cross form micro-fluidic chip. ►The injection mode can control the length of sample plug from one to ten channel widths. ► The injection mode overcome electrophoretic bias and prevented sample leakage successfully. ► Seven oligopeptides were separated and determined by microchip with reflux injection mode.