| As a kind of heavy metal,Cd（II）is widely used in industrial production and is considered as one of the most harmful water pollutants.Cd（II）is easily investigated and absorbed and accumulates in the body through the food chain,damaging the kidneys,liver,bones and blood,and causing great threats and high damage to human health.Therefore,the efficient detection of Cd ions is of great significance.Electrochemical analysis is widely used in the detection of metal ions because of its simple,rapid,sensitive and low cost,but it has poor selectivity for specific ions.However,ion-imprinted polymers（IIPs）are highly selective polymers for target ions.Combined with the electrochemical analysis method,the electrochemical sensor constructed has not only excellent recognition performance for target ions,but also high sensitivity,rapid effectiveness.In this paper,three different ion imprinted electrochemical sensors were prepared by combining the sensitivity of ion imprinting technology and electrochemical analysis method with Cd2+as the simulated ion.Its morphology and electrochemical properties were analyzed by characterization,and its selectivity,repeatability and stability were studied.Finally,the prepared ion-imprinted electrochemical sensor was successfully used for the detection of cadmium ions in actual samples.The specific contents are as follows:（1）Fabrication and performance study of cadmium ion imprinted electrochemical sensor based on gold nanoparticle:ion-imprinted polymers（IIPs）were successfully prepared by using Cd2+as template ion,thiosemicarbamide chitosan（TSFCS）and methacrylic acid（MAA）as functional monomers,EGDMA as cross-linking agent,AIBN as initiator,and gold nanoparticles as doping monomers.Then,carbon paste electrodes were prepared by mixing them with graphite powder and paraffin oil in a certain proportion and Cd（Ⅱ）ion-imprinted electrochemical sensor was constructed.Through conditional optimization,the following results were obtained:the optimal p H value of electrolyte is 7,the optimal polymer content is 30%,the optimal scanning rate is 70 m V/s,and the optimal pulse time is 50 ms.Under the optimal conditions,the prepared sensor showed a good detection ability for cadmium ions,with the linear detection range of 1×10-9～1×10-4 mol/L and the detection limit（LOD）of 1.43×10-10mol/L（S/N=3）.Three kinds of ions(Cu2+,Fe3+and Zn2+)were selected to analyze the selectivity of the sensor,and the results show that it has a high selectivity to cadmium ions.Finally,the sensor has been successfully applied to the analysis and detection of Cd（Ⅱ）in real samples（tap water,river water and rice）,and the recovery range is 98%～107%.（2）Preparation and performance of cadmium ion imprinted electrochemical sensor modified by r GO@Ti O2:Cadmium ion mesoporous imprinted polymers were prepared by using surface imprinting technology,using Cd2+as template ion,Aminopropyl triethoxysilane（APTES）as functional monomer and cetyltrimethylammonium bromide（CTAB）as poreforming agent.Then,Cadmium ion mesoporous imprinted polymers and the prepared composite r GO@Ti O2 were dissolved in solvent at a certain proportion.Finally,Cd（Ⅱ）ion-imprinted electrochemical sensor was constructed by drip-coating it onto a glassy carbon electrode.Through conditional optimization,the following results were obtained:the optimal p H value of electrolyte was 6,the optimal ratio of r GO@Ti O2 to IIPs was 1:2,the optimal scanning rate was 50 m V/s,and the optimal elution time was 20 h.Under the optimal conditions,the prepared sensor shows a good detection ability for cadmium ions,with the linear detection range of 0.01～10μM and the detection limit（LOD）of 1.2×10-8 mol/L（S/N=3）.Three kinds of ions(Cu2+,Fe3+and Zn2+)were selected to analyze the selectivity of the sensor,and the results show that it has a high selectivity to cadmium ions.Finally,the sensor has been successfully applied to the analysis and detection of Cd（Ⅱ）in real samples（tap water,river water and rice）,and the recovery range is 96.4%～109.0%.（3）Preparation and performance of cadmium ion-imprinted electrochemical sensor based on Multi-walled Carbon Nanotubes:Ion-imprinted polymers（IIPs）were synthesized on the surface of multi-walled carbon nanotubes（MWCNTs）using Cd2+as template ion,isopropylacrylamide and acrylic acid as functional monomers,and ammonium persulfate as initiator.The IIPs and the prepared composite r GO@Ti O2were dissolved in a solvent at a certain proportion.Finally,Cd（Ⅱ）ion-imprinted electrochemical sensor was constructed by drip-coating it onto a glassy carbon electrode.Through conditional optimization,the following results were obtained:the optimal p H value of the electrolyte was 6,the optimal ratio of r GO@Ti O2 to IIPs was1:1,the optimal scanning rate was 70 m V/s,and the optimal elution time was 24 h.Under the optimal conditions,the prepared sensor showed a good detection ability for cadmium ions,with the linear detection range of 10-6～10-9mol/L and the detection limit（LOD）of 1.12×10-9 mol/L（S/N=3）.Three kinds of ions(Cu2+,Fe3+and Zn2+)were selected to analyze the selectivity of the sensor,and the results show that it has a high selectivity to cadmium ions.Finally,the sensor has been successfully applied to the analysis and detection of Cd（Ⅱ）in real samples（tap water,river water and rice）,and the recovery range is 97%～106%.In summary,three novel Cd imprinted electrochemical sensors based on gold nanoparticles,r GO@Ti O2 and multi-walled carbon nanotubes were prepared in this paper,and their physical and chemical properties were characterized and analyzed.The results show that the prepared sensors have high selectivity and sensitivity to Cd（Ⅱ）ions.It has been successfully applied to the analysis and detection of cadmium ions in real samples（tap water,river water and rice）. |
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