New Galvanometric Electrochemical Sensor For Detection Of Trace Potassium Ion In Aqueous Solution Lang Luting

With the development of science and technology,economy and people's living standard,people are more and more demanding of their health.Modern scientific research has proved that the major elements play an important role in the organism,and their deficiency or excess are closely related to the health of people and the high yield of plants.Potassium is one of the essential substances in life,and is the main cation in the intracellular fluid.The abnormal state of potassium ion concentration may cause a variety of diseases in animals.Potassium is absorbed into the plant with the free state,and it is an activator of the enzyme to participate in many important metabolic activities in the plant.When potassium content is appropriatein the organism,it can also increase the intensity of protoplast hydration,thus enhancing the water holding capacity of the cells.When the potassium content is deficient in the organism,the leaf color is green,the growth is slowand the leaf margin is dry.Therefore,the content of potassium ion is also an important indicator in the diagnosis of plant ion content.Accurate determination of potassium is the key to clinical diagnosis and nutritional analysis.In order to solve the problem of quantitative detection of potassium ions,aiming at the problem of difficulty in electrochemical sensor detection process and how to measure the amount of potassium in plant juice and human blood.On the basis of the advantages of good repeatability,low cost and easy batch production in the screen printing technology,thus the innovation and improvement of sensor electrode and immobilization of biochemical molecules were carried out.In this paper,two new kinds of electrochemical sensors for the detection of potassium ions were developed,and the feasibility of these techniques for the rapid detection of potassium ions was demonstrated:1 Research on potassium ion electrochemical sensor based on 4-amino dibenzo-18-crown-6 printed electrode:(1)In order to improve the electrochemical properties of the surface of the screen printing electrode,the chemical pretreatment method(treated in dilute water or piranha solution)and the electrochemical pretreatment method(the gold electrode was placed in dilute sulfuric acid for cyclic voltammetry Scan)is used,and In the pretreatment process,using cyclic voltammetry(CV)to scan(8 times).Finally,the cyclic voltammetry curves obtained by cyclic voltammetry(CV)were used to compare the changes of the oxidation peak and the reduction peak current value before and after the two pretreatment methods.It is found that the electrochemical pretreatment method(method two)can make the electrochemical characteristics of the surface of the screen printing gold electrodeimproved significantly,which is helpful to improve the detection precision and sensitivity of the electrode.(2)In order to improve the fastness and precision of the electrochemical sensor and the high selectivity to the potassium ion,the mercaptoethylamine was selected as the material of the modified electrode,glutaraldehyde was used as the crosslinking agent.At the same time,the molecular self-assembly method was used to form a stable and ordered self-assembled film on the surface of the gold electrode.And the 4-aminodibenzo-18-crown-6 was modified on the electrode surface by molecular polar covalent bond.As the crown ether and metal cations have a good specific binding capacity,so then potassium and 4-aminodibenzo-18-crown-6 were complex.Through the process of CV scanning reaction of electrochemical sensors,we found that the oxidation peak current value and potassium ion concentration in the range of 0.02mM to 0.16mM has a significant linear relationship.At this timethe probability of significance test is less than 0.0001,and the determination coefficient is about0.976.In order to further utilize the time control of electrochemical measurement technology,the time-current method is used to measure the potassium ion of the electrochemical sensor.It is found that when the potassium ion concentration is in the range of 1 nM to 10 nM,the model has significant linear relationship.At this time the probability of significance test is less than 0.0001,and the determination coefficient is about 0.996.The test not only can significantly improve the electrode reversibility and conductivity,which is conducive to improving the sensitivity of the sensor,but also conducive to the production of micro-potassium ion sensor.2 Research on potassium ion electrochemical sensor based on fluorescent group labeled oligonucleotide chain:In this paper,we introduced the idea of specific binding of with metal cations into the sensor,and used a kind of oligonucleotide array(IBA)as probe to determine potassium ion.Dropped potassium on the surface of gold electrode,using linear potentiometric method to inspect the electrochemical feature of surface on gold electrode,then added the oligonucleotide solution on the surface of gold electrode,using cyclic voltammetry(CV)to determine the oxidation peak current.Combine the change of oxidation peak current before dropping with after dropping,determining the quantity of potassium ion.It showed a good liner relationship on the change difference between potassium ion concentration and the oxidation peak current in the range of 0.2mM to 1.4mM,the probability of significance test is less than 0.0001,and the determination coefficient is about 0.996.And applied this method to the determination of banana,the results were so closed to the results that traditional ion chromatography determined,the relative standard deviation was 0.53%.As a result,this method has a high accuracy for the detection of potassium ion,which is beneficial to the fabrication of micro potassium sensor.