| The Prussian blue (PB) exemplifies a mixed-valence compound, exhibit interesting (even extraordinary), photpphysical, magnetic and excellent electrochemical stability. Therefore, PB is widely used in many fields, such as electrocatalysis, sensors, electrochromism, photoresponse, rechargeable battery devices and electroanalytical chemistry.In essence, PB should be considered a disordred structre of complex compouds, it contains a total of deposit or occluded ferrous ions, uncertain water and possible hydrolysis of cyanide and so on. Actually, people still have no better understanding of PB structure, but a unified point of view is:PB structure similar to that of zeolite, which allows some small-size molecules through the pore.Therefore, we use the Prussian blue to prepare the electrochemical sensors, study its efficient catalytic properties, as well as special agent for the structure of the simulation. PB can be applied in the low voltage where it exhibits excellent electric catalytic performance to avoid the interference of some electric active substance. Compared to some difficult to store and expensive enzyme electrodes, PB is more cheap and has better performance, prompting PB on the analysis of the application is superior to the other vehicle. However, the stability of PB in the alkaline environment conservation is a big problem. The main research work of this paper includes two parts:1. Doping ionic liquid for the first time, decrease the degree of depolarization, facilitating entangled states of polyaniline chain to extend state transitions, which is beneficial to the coating Prussian blue have more active site, thus improve the performance of the PB。 We prepared a new kind of carbon nanotube-ionic liquid/polyaniline composite materials-Prussian blue-Prussian blue oxidase electrode sensor. Through extensive research and preliminary study, we proposed using coating method and cyclic voltammetry to get deposition composite membrane. We investigated the structure and electrochemical properties of the composite membrane, and discussed the concentration of carbon nanotubes coated drops, the doping amount of the ionic liquid in the plating solution and coating laps affect the performance of composite membrane, etc. MWNTs/IL-PANI/PB composite membrane response to H2O2 very fast, with good reproducibility, especially in the weak alkaline environment, it has good stability, high sensitivity and wide linear range. Then we also drip with glucose oxidase-chitosan solution to prepare MWNTs/IL-PANI/PB hybrid membrane glucose sensor. Experiments show that the sensor has excellent performance and good anti-interference ability.2. We also design a sensor as cell simulation to research the transportation of K+ trans-membrane and the mechanism of the resting potential, which use PB’s special structure and its selective permeability for potassium ion. Firstly, drop coating method is used to deposit a layer of carbon nanotubes with the purpose of the act in electrical signals, then prepared a layer of Prussian blue particles on the electrode surface. When K+ concentration of modified PB layer is higher than that in the electrolyte, K+ in the modified layer will transfer to the solution continuously by the effect of concentration gradient, which is the equivalent of K+ pump turning on and K+ transporting across the membrane from cell to extracellular environment. The declining of electrode potential is equal to the decrease of membrane potential. At the same time, due to the electrically neutral structure of PB, K+ in the solution has a tendency to transfer into the PB layer. K+ will no longer diffuse to the solution until a certain extent. Although concentration gradient of K+ between modified layer and solution still exists, macro migration will not happen because of the relative equilibrium between the two forces, meanwhile the equilibrium potential of electrode is equivalent to the resting potential of cell membrane. |
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