Preparation Of Iron-Based/Carbon-Based Nanomaterials And Their Electrochemical Detection Of Small Molecules In Drugs

Excessive use of drugs may lead to their accumulation in the body,thus threatening human health.The pollution of ecological water by drugs will also bring indirect threats to human health.For example,overuse of the antipyretic analgesic acetaminophen（AP）can cause irreversible toxic side effects to human organs.Dopamine（DA）is a neurotransmitter that transmits information between neurons.Abnormal DA concentrations can cause many diseases.Therefore,it is of great significance to accurately and efficiently detect the concentration of biological small molecules in water and body.Electrochemical method has attracted extensive attention due to their advantages of short response time,high sensitivity,and simple operation.Iron-based compounds have unique chemical structures and thus have good electrocatalytic properties.Carbon nanomaterials have large specific surface areas,which can increase the adsorption sites of iron-based compounds.Based on the synergistic effect of iron-based compounds and carbon nanomaterials,their composites have the potential to be applied to electrochemical detection of small biological molecules.The important contents of this thesis are as follows:1.α-Fe₂O₃/CNTs composites were synthesized by a simple hydrothermal method.Then,the Fe₂O₃ in the composite was transformed fromαphase toγphase after treatment with hydrazine hydrate at relatively low temperature.The VSM results show that the saturation magnetization of the composite increases from 0 to 1.29 emu/g during the phase transition.In addition,the electrochemical properties ofα-Fe₂O₃/CNTs andγ-Fe₂O₃/CNTs were also investigated.Compared withα-Fe₂O₃/CNTs,theγ-Fe₂O₃/CNTs modified electrode has stronger electrocatalytic activity towards AP.Under the optimal conditions,the linear range of the modified electrode is 2.5-385μM and 593-1550μM,the detection limit is 0.046μM.The modified electrode also has good stability and repeatability.Finally,the constructed sensor was successfully applied to detect the concentration of AP in different water bodies,provides an idea on the construction of novel electrochemical sensors for AP detection.2.Metal-organic framework MIL-101（Fe）precursor with high specific surface area was synthesized by solvothermal method.Then,under the protection of inert gas Ar,Fe/C composites was synthesized by high temperature calcination in a tube furnace.The effect of calcination temperature on the morphology and structure of the material was investigated.TEM results show that the material morphology can remain intact in a certain temperature range.Among them,the material（Fe@C）prepared by calcination at 900°C has greater catalytic activity towards DA,which may be due to its larger specific surface area.When Fe@C modified glassy carbon electrode（Fe@C@GCE）was used for electrochemical detection of DA,the detection limit was 0.1μM,the linear range was 0.5-866.7μM,and the sensitivity was7.464μA·m M^-1·cm^-2.In addition,the modified electrode also has good repeatability,stability and selectivity.These results suggest that Fe@C@GCE is a novel electrode material that can be used for DA detection.3.A series of Fe/Fe₃N-based nanocomposites were synthesized by high temperature pyrolysis.Structural characterization shows that the carbon layer uniformly covers the surface of Fe/Fe₃N nanoparticles.The thin carbon layer can effectively improve the stability of Fe/Fe₃N and accelerate the electron transfer between Fe/Fe₃N and the electrode.Fe/Fe₃N also has good electrical conductivity and large specific surface area,these advantages enhance the electrochemical performance of the constructed Fe/Fe₃N@C-900@GCE.When the modified electrode is used to detect DA and AP individually,the linear ranges for DA and AP are 0.05-66.4μM and 0.05-56.9μM,respectively,and the detection limits（signal-to-noise ratio of 3）are 0.05μM and 0.04μM,respectively.In addition,the modified electrode also has high sensitivity,good stability and good selectivity.When the modified electrode is used to detect DA and AP simultaneously,the two peaks from them are well separated.Finally,the modified electrode has also been successfully applied to the detection of DA and AP in real samples.The paper has 39 figures,6 tables and 152 references.