Investigation On Electrochemical Sensors For Saccharide Based On Phenylboronic Acid Bearing Polymer

Phenylboronic acid and its derivatives can form high affinity reversible covalent bonds rapidly with diol compounds to generate cyclic esters in basic aqueous media or nonaqueous. So phenylboronic acid derivatives have been extensively explored to develop various saccharide receptors. In this paper, we investigate an electrochemical amplification approach for saccharide detection based on phenylboronic acid-saccharide interaction coupling with a redox cycling, molecular imprinting technology and nanomaterials amplification effec. Obviously, these studies may provide a new way to fabricate the electrochemical sensor for saccharide based on phenylboronic acid and its derivatives plexation. The main contributions of this thesis included four sections in following:1.The research progress of electrochemical sensors based on phenylboronic acid-saccharide interaction was reviewed comprehensively. The research main and significance content of this paper were aslo introduced.2. Phenol and3-hydroxyphenylboronic acid were electrochemically co-polymerized on a glassy carbon electrode in the presence of phenazine methosulfate (PMS), to form redox-poly(phenol-co-3-hydroxyphenylboronic acid). The as-synthesized phenylboronic acid bearing redox-polymer was characterized by UV-visible spectroscopy and cyclic voltammetry. The behavior of Fe(CN)63-reduction by electro-generated PMSred via a redox cycling was studied. With the addition of saccharide, a stable negative charged surface was formed owing to the generation of phenylboronate ester and then limited the access of Fe(CN)63" due to electrostatic repulsion. The attenuated electrochemical signal amplification of Fe(CN)63" was dependent on the concentration of saccharide. The dynamic ranges of the fabricated electrochemical sensor were1-100μmol·L-1for D-fructose,10-300μmol-L-1for D-mannose and20-500μmol·L-1for D-glucose, respectively. The detection limits were ca.0.3μmol·L-1for D-fructose, ca.3.5μmol·L-1for D-mannose and ca.7.8umol-·L-1for D-glucose, respectively. 3. Potentiometric detection of saccharides based on highly ordered poly (aniline boronic acid)(PABA) nanotubes modified electrode was systematically investigated. The PABA nanotubes were first fabricated by electrochemical polymerization of3-aminophenylboronic acid in an anodic alumina oxide (AAO) membrane. This study showed that the as-synthesized PABA nanotubes had a very porous structure with small diameters and high surface area, and gave significantly better performance in both sensitivity and response time compared to conventional poly(aniline boronic acid) films. The experimental results show that the sensor could detect D-glucose and D-fructose in a linear range of2.0～14mmol·L-1. The proposed sensor showed much high sensitivity to D-glucose (ca.1.5mV-mM"1) and D-fructose (ca.3.5mV·mM-1) with fast response time for D-glucose (65s) and D-fructose (23s). The detection limit was estimated to be0.5mmol-L-’for D-glucose and0.2mmol·L-1for D-fructose (S/N=3).4. The molecularly imprinted polymer (MIP) film was prepared by electropolymerization of phenol and3-hydroxyphenylboronic acid on a glassy carbon electrode in the presence of D-glucose as a template. The polymer feature of the modified electrode was characterized by the electrochemical technology. With the addition of D-glucose, a stable negative charged surface was formed owing to the generation of phenylboronate ester and then adsorb the probe ions of Ru(NH3)63+in solution. The electrochemical signal amplification was obtained via Fe(CN)63"catalytically reduction of Ru(NH3)63+, and then was dependent on the concentration of glucose. Due to molecular imprinting technique can improve the effectively selectivity of the sensor, which indicate a higher response for D-glucose over D-mannose and D-galactose. The dynamic ranges of the electrochemical sensor were0.2～3.5mmol-L-1for D-glucose with a detection limit of0.1mmol·L-1(S/N=3).