A bio/chemical analysis system with functions such as automatic mixing of solutions, pH-regulation, and detection based on electrochemiluminescence (ECL) was developed. A sample solution (amino acid) and a necessary reagent solution (Ru(bpy)32+) were automatically mixed in a chamber using a valve electrode that opened based on electrowetting. The solution pH were regulated by using three-electrode system in an irregular manner. By applying a positive potential to iridium working electrodes, ECL was observed. The ECL intensity has increased as the solution pH and concentration of amino acid increase.

　When the sample solution was filled in one of the compartments, the hydrophobic valve area could effectively suppress the intrusion of the solution into the other. Next, the reagent solution was transported. When it arrived at the Ag/AgCl reference electrode, the electronic circuit was completed. As a result, the valve area become hydrohobic, and the two solutions were mixed. After two solutions were mixed, the solution pH was adjusted in the reaction chamber. The pH was fixed at 11 by the pH-regulator. In the log-log plot, the ECL intensity changed for all amino acids approximately linearly. As a result, amino acids concentration detection are possible by using this system. The detection limit was 0.1 nM for L-proline, 0.5 nM for L-leucine and L-lysine, 1 nM for L-valine, 50 nM for L-histidine.