Research Of Electrophoresis Chip Amperometric Detection Key Technology

With the development of science and technology, capillary electrophoresis chips are widely used in biochemistry, biomedical, clinical, medicine, environment, etc. fields. At present, electrochemical detection methods for capillary electrophoresis chip, include potential detection, conductivity detection and amperometric detection, among them, because that amperometric detection method owns high sensitivity, good selectivity, less samples, no diameter restrictions, no demand to translimitance of the detection part, inexpensive, easy integration and miniaturization and so on, it has been paid more and more attention by majority of researchers, meanwhile, it is widely used in the electrochemical detection method gradually.The paper designed capillary electrophoresis amperometric detection chip for testing arginine, which took plexiglas (PMMA) as substrate. Through theoretical analysis and design of the chip, determined the impact factors of test limit and sign,that conclude electrode material and type, relative position of three electrodes in test pool, test pool size, applied electric field strength, pipe length and cross-sectional area and so on. The paper gave the reasonable and effective production process programs. At the same time, detected the electroosmotic flow of affecting amperometric detection sensitivity and column efficiency, and modified channels of the chip by hydroxyethy cellulose (HEC), before and after HEC modification, compared the effect of bonding temperature on the electroosmotic flow. Experimental results show that with the increasing hot bonding temperature, the electroosmotic flow reduces, after modification, the electroosmotic flow of the borax buffer increases significantly, so that the electroosmotic flow can control effectively. Using electroplating method produced Ag/AgCl reference electrode, designed three-electrode A type capillary electrophoresis chip structure that are vertical to each other, and B type capillary electrophoresis chip structure that working electrode is perpendicular with reference electrode and auxiliary electrode. According to capillary-chip amperometric detection theory, cyclic voltammetry characteristics were detected for the A-and B-type capillary electrophoresis chips, the experiment results show that A-type chip characteristics is super than B type's, it's oxidation-reduction reaction obviously, and L-arginine testing can be achieved.