Preparation Of Nanoparticles Modified PVC Membrane Electrodes And Their Drug Detection Performance

Compared with other analytical methods,ion selective electrode analysis has the advantages of low prices,easy to carry,wide detection concentration,simple and quick operation,not affected by sample color,turbidity,suspended solids or viscosity,etc.Thus,it has been widely used in healthcare,biochemical analysis,food safety and environmental monitoring and many other fields.However,in the actual application process,the detection limit can not meet the actual needs,and other issues about ion selective electrode analysis still exist.Therefore,further improvements on electrode performance,like reduce the detection limit,increasing the speed of response,has become the bottlenecks which limit the development of ion selective electrodes.Because of their size effect,nanomaterials exhibit unique chemical,physical and electronic properties that can be used for improving the performance electrode sensors.Recently,nano-materials as modifiers to modify electrode for improving the electrochemical performance,are the forefront research interest in electrochemical analysis field.The reported results show that nanomaterials and nano-composite materials have been used to modify and prepare ion-selective electrodes,which significantly improves the performance of ion-selective electrodes.In this thesis,the PVC membrane electrodes were used for detecting diltiazem and ractopamine.Using complexing interactions between drug molecules and the agents such as bismuth nitrate and sodium tetraphenyl boron,we prepared electrode active material.And those electrode active materials were used to prepare PVC membrane electrodes.To further improve the electrochemical performances of PVC film electrode,we prepared TiO₂ nanoparticles and sodium tetraphenyl borate monodisperse nanoparticles to modify PVC membrane electrodes.The morphology of the resulting nano-materials and electrode surface were characterized by SEM and TEM method.The lattice structure and growth-orientation were characterized by XRD reflections.The component of the obtained materials was analyzed by FT-IR.The size distribution of the obtained particles was characterized by DLS?dynamic light scattering?.The electrochemical behavior and parameters were analyzed by cyclic voltammetry method.The main contents and conclusions are drawed as follows:?1?Using sodium tetraphenylborate and iodine salt as precipitant to form active material with diltiazem,which named as DTM-TPB and DTM-Hg,respectively.Based on these two materials,we fabricated three electrodes:DTM-TPB modified membrane electrode,DTM-Hg modified membrane electrode and DTM-Hg coated silver fiber electrode.All these three electrodes were then used for DTM detection.The results revealed DTM-TPB modified membrane electrode presented a widest response concentration ranged from 1.0×1.0×10^-2?1.0×10^-5 mol·L^-1 and a lowest detection limit of 3.2×10^-6 mol·L^-1.?2?We prepared monodisperse,colloidal stable TiO₂@DTMBi nanospheres in a average size of 40 nm.The favourite TiO₂/DTMBi ratio of prepare TiO₂@DTMBi nanospheres is 1:1.When used TiO₂@DTMBi nanospheres modified PVC membrane electrode to detect DTM,we got a response concentration range of 1.0×10^-1?1.0×10^-7 mol·L^-1 and a low detection limit of 0.2?g·mL^-1.These two results are better than the known data from literature.We inferred that these improvements were attributed to the increased response surface erea and faster electron transfer capability on the electrode induced by TiO₂@DTMBi nanospheres.?3?We propose a method to prepare ractopamine-sodium tetraphenylborate nanocompletes by the viture of self-assembly induced by the interaction between positive RAC and negative charged TPB.The size of the obtained RT NPs is ranged from 30?50 nm.When used RT NPs modified PVC membrane electrode to detect RAC,we got a response concentration range of 1.0×10^-1?1.0×10^-7 mol·L^-1 and a low detection limit of 7.4×10^-8 mol·L^-1.The response time could be as short as 10 s.When used RT NPs modified PVC membrane electrode to detect RAC in pork samples,the results show high recovery and low relative standard deviation.?4?Our results indicate that using TiO₂ and RT NPs to modify PVC membrane electrode can significantly improve the performance of the electrode in drug testing.Our proposal is a kind of promising method in ion selective electrode analysis field.