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目的将Cu2+和碳纳米管(MWNTs)固定于脱氧核糖核酸(DNA)和聚丙烯胺(PAA)中,形成MWNTs/Cu2+-DNA/PAA纳米复合物,并用此纳米复合物构建了一种新的过氧化氢生物传感器。方法将该纳米复合物修饰玻碳电极应用于过氧化氢的测定。结果 Cu2+和MWNTs之间对过氧化氢的还原具有协同电催化作用。在pH=5.0的磷酸盐缓冲溶液中,与DNA/PAA复合物中只存在Cu2+或MWNTs的复合物修饰玻碳电极相比,对过氧化氢的还原电催化稳态电流分别提高了约7倍和2.5倍。所制备的生物传感器对过氧化氢的线性范围为5.0μmol/L~4 mmol/L,检测下限为2.5μmol/L(S/N=3)。结论在电极表面涂覆一层Nafion膜可以有效消除抗坏血酸、尿酸对过氧化氢的测定影响。这种新型传感器的优越性在于它可以克服天然酶易失活、不稳定的缺点而具有良好的重现性与稳定性。
Objective To immobilize Cu2 + and carbon nanotubes (MWNTs) in deoxyribonucleic acid (DNA) and polyacrylamide (PAA) to form MWNTs / Cu2 + -DNA / PAA nanocomposites and to construct a new Hydrogen peroxide biosensors. Methods The nanocomposite modified glassy carbon electrode was applied to the determination of hydrogen peroxide. Results Cu2 + and MWNTs have a synergistic electrocatalytic effect on the reduction of hydrogen peroxide. In pH = 5.0 phosphate buffer solution, the reduction electrocatalytic steady state current of hydrogen peroxide was about 7 times higher than the composite modified glassy carbon electrode with only Cu2 + or MWNTs in the DNA / PAA complex And 2.5 times. The linear range of biosensor to hydrogen peroxide was 5.0μmol / L ~ 4mmol / L, and the detection limit was 2.5μmol / L (S / N = 3). Conclusion Applying a layer of Nafion membrane to the electrode surface can effectively eliminate the influence of ascorbic acid and uric acid on the determination of hydrogen peroxide. The advantage of this new sensor is that it can overcome the natural enzyme inactivation, instability disadvantage and has good reproducibility and stability.