| As a widely distributed metal element in nature,sodium has important applications in industrial production and water balance in organisms.As a combustion supporting agent,sodium ion in cigarette paper can improve the "ash wrapping" performance of cigarette paper and promote the adhesion of ash flakes after cigarette paper combustion.The accurate determination of sodium ion content in cigarette paper can be used as an important basis for evaluating the quality and performance of cigarette paper.The existing sodium ion determination methods include flame atomic absorption spectrometry,ion chromatography and other instrumental analysis methods,but its detection equipment is difficult to be used for on-site detection.Therefore,the research on electrochemical test methods with high sensitivity and in-situ real-time analysis is of great significance to expand the methods and technologies for on-site determination of sodium ions in cigarette factories.Based on this,molecular mechanics calculations were performed on the interaction between the solid-state conduction layer and different sodium ion carriers and alkali metal ions in the solid-state sodium ion selective electrode,and tetraethyl 4tert-butyl-calix[4]arene-O,O’,O",O’"-tetraethyl was selected as the carrier to construct a MoS2@CuO-based solid-state sodium ion selective electrode,and after the optimization and comparison of the cigarette paper.After optimizing and comparing the detection system,the ion-selective electrode method for the detection of sodium ions in cigarette paper was investigated for its applicability,and the rapid and sensitive detection of sodium ions in cigarette paper by GCE/MoS2@CuO/Na+-ISM electrode was achieved.The main studies are as follows:1.Molecular simulation of solid-state conduction layer and interaction of sodium ion carriers with alkali metal ionsThe self-diffusion coefficients of Na+and its conductivity in different systems when using different nanomaterials such as MoS2,ReS2,CuO,Fe2O3,MoS2@CuO,and MoS2@Fe2O3 as solid-state conduction layers were calculated by the method of molecular mechanics theory.Na+has good self-diffusion coefficients in the MoS2@CuO and MoS2@Fe2O3 systems,and the conductivity of the systems 5.63×102 S/cm and 5.82×10-2 S/cm,respectively.The interaction of carriers with alkali metal ions and their hydrated ions in different sodium ion electrode sensitive films was investigated.The energy and geometry of six different sodium ion carriers and their complexes formed with three alkali metal ions,Na+,K+and Rb+,were analyzed after optimizing their full geometrical structures.The results showed that the reasons affecting the stability of each carrier under the gas phase were related to the binding energy of the complexes,and the solvent effect also had a large influence on the interaction between the host and the guest,but the structure of the complexes formed by each carrer with Na+ was the most stable.Among the six carriers,4-tert-butylcalix[4]arene-O,O’,O",O’"-tetraethyl showed the best binding interaction performance to sodium ions.2.Construction of solid sodium ion electrode based on MoS2@CuOMoS2@CuO nanomaterials were synthesized by hydrothermal method,and the successful synthesis of MoS2@CuO nanocomposites was demonstrated by SEM and XRD characterization analysis.The GCE/MoS2@CuO/Na+-ISM electrode was constructed by titrating a sodium ion-selective membrane with 4-tert-butylcalix[4]arene-O,O’,O",O’"-tetraethyl as a solid conductive layer.The sodium ion electrodes with MoS2,ReS2,and MoS2@Fe2O3 as solid conduction layers were also compared,and the GCE/MoS2@CuO/Na+-ISM electrode showed superior performance.It has a good linear response in the range of 1.0×10-5～1.0×10-2 mol/L with a response slope of 54.57± 1.03 mV/dec,which is in accordance with the Nernst response relationship.The electrodes showed good stability in aqueous layer testing and chronopotential analysis,which was better than those without solid-state conduction layer,indicating that the sodium ion-selective electrodes based on MoS2@CuO solid-state conduction layer have good application prospects.3.Application study on the rapid determination of sodium ion content in cigarette paperThe application of ion-selective electrode method to the determination of sodium ion content in cigarette paper was discussed.Two pretreatment methods of nitric acid digestion and acetic acid extraction for cigarette paper of samples were compared.It was found that the pretreatment of cigarette paper using the acetic acid extraction method was convenient and easy,bringing little operational error.The intra-day and inter-day average relative deviations were within 5%for different batches of cigarette paper product specimens tested at different times in the optimized diisopropylamineacetic acid buffer system(pH=11.5)with good sample recoveries,indicating the reliability of the sodium ion selective electrode method.The cigarette paper samples were tested by the GCE/MoS2@CuO/Na+-ISM electrode,and the recoveries ranged from 95.5%to 105.0%,indicating that the electrode has good application prospects for real-time monitoring and safety assessment.It can meet the practical application requirements and can be applied to the rapid detection in the cigarette factory workshop site. |
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