| Hydrogen peroxide (H2O2), a product of catalyzed reactions by oxidases or catalase, is an essential mediator in many areas including food, clinical and environmental analysis, so the rapid and sensitive determination of a small quantity of H2O2has become an extremely important research topic in recent years. It has important medical implications on the prevention, diagnosis and monitoring of clinical disease. Metal-organic coordination polymers (MOCPs) possesses abundant and excellent properties, especially their large specific surface area, structure diversity, and mutil-functionality, thus are expected to be used for the development of the high performance enzyme-free electrochemical biosensors, however, rather limited attention were paid on it. Nano-material presents diversified and unique nano-merits, making it be applicated in many fields. So biosensors which based on nanomaterials have become a hot topic and focus. In this thesis, we synthesized biocompatible nano-scale metal-amino acid polymers, and prepared a new enzyme-free electrochemical biosensor for the detection of H2O2. The main contents are as following:1. The preparation and characterization of ([Cu(tyr)2]n).Cu(Ac)2·2H2O, which has valence state, unsaturated metal sites and empty d orbitals, and biological molecules L-tyrosine were chosen as chemical reactants, the effects of reaction conditions (different synthesis methods, pH value, reaction time, surfactant) on the polymer size were discussed in detail, the results showed that we successfully synthesized a nanostructured [Cu(tyr)2]n under ultrasonic irradiation and in the presence of a surfactant PVP. The acquared [Cu(tyr)2]n were characterizaed by XRD, TEM, FTIR. XRD results indicated that [Cu(tyr)2]n was identical to CCDC-176587reported in the literature. TEM image indicated the [Cu(tyr)2]n nanostructures had a nanorods with an average size of200nm in wideth and0.5～2μm in length, the particles well dispersed and no obvious agglomeration were found.2. The preparation of [Cu(tyr)2]n/GC electrode, its electrochemical properties and electrocatalytic activity toward the reduction of H2O2, and its application in respect of catalytic synthesis and enantiomer separation. The [Cu(tyr)2]n/GC electrode was fabraicated by modifying [Cu(tyr)2]n on the GC electrode surface. The cyclic voltammetry of [Cu(tyr)2]n/GC electrode can give a couple quasi-reversible redox peaks about CuⅡ/CuⅠ in the potential range of-600～400mV with the cathdic (Epc) and anodic (Epa) peak potential of ca. Epc=-250mV, Epa=-50mV (vs. SCE) and the formal potential of E0=-150mV, which was almost independent on the scan rate. The electrode response time was less than3s. This fast response can be attributed to the direct electron transfer from the copper(II) polymer to the electrode surface. Besides, the chronoamperometry of Cu(tyr)2]n/GC electrode showed a good linear range from4.0×10-2mM to6.3mM at a detection potential-200mV (with a correlation of0.998). The detection limit was estimated1.0×10-2mM (S/N=3), the sensitivity was about70mAmol-1Lcm-2. We had successfully prepared a novel enzyme-free biosensor for the detection of H2O2. The biosensor has a short response time, wide linear range, excellent reproducibility and a strong anti-jamming. In addition, we preliminary studied its application in catalytic synthesis and enantiomer separation. The results showed it can be used for the asymmetric addition of catalytic aromatic aldehydes and aromatic alkynes at the conditions of80℃with isopropyl alcohol as solvent,1,10-phenanthroline as ligand, S-shaped enantiomers can be obtained by the chiral separation of adducts.3. The preparation, electrochemical properties and its electrocatalytic activity toward the reduction of H2O2.[Cu(asp)]n nanostructure were synthesized under stirring with Cu(NO3)2·3H2O and L-asp as reactants. The prepared [Cu(asp)]n were characterizaed by XRD, SEM, FTIR. The XRD pattern of [Cu(asp)]n was in consistent with the literature. SEM image indicated the [Cu(asp)]n nanostructures had a nanorod like microstructure, with an average size of100～200nm in wideth and1～2μm in length, the particles dispersed well, and no obvious agglomeration was observed. The [Cu(asp)]n/GC electrode was fabraicated by modifying [Cu(asp)]n on the GC electrode surface. The chronoamperometry of [Cu(asp)]n/GC electrode showed a good linear range from3.4x10"2mM to6.8×10-1mM at a detection potential-150mV (with a correlation of0.998). The detection limit was estimated2.0×10-3mM (S/N=3), the sensitivity was about110mAmol-1Lcm-2. In conclusion, the NMOFs biosensor has a short response time and highly sensitivity, which has a great potential of being applicated in biosensors and relevant areas. |
PDF Full Text Request