| Wasting water contains many heavy metals ions from industries and agriculture.The detection of heavy metals in aqueous solutions is particularly important to environment safe and health.Aiming at the problems of complex operation,expensive price,and low sensitivity in heavy metal detection,this study designed and synthesized silver coated functional gold nanomaterials and triangular silver nanoparticles to construct detection systems for heavy metal ions using these two materials as probes.In this study,heavy metal chromium（Ⅲ）and copper ions were used as detection targets.The main research results were as follows:（1）Synthesis of tetramercaptobenzoic acid（4-MBA）functionalized Au@Ag NPs and its detection of Cr3+ions.In this part of the study,functional Au@Ag NPs was firstly synthesized,and then a colorimetric detection system for 4-MBA-Au@Ag NPs was constructed.The effects of the concentration of 4-MBA and the p H of the system on the 4-MBA-Au@Ag NPs detection system were studied,and the sensitivity and interference resistance of the system were investigated.Simulated samples were also tested.Studies have shown that the concentration of 4-MBA and the p H of the system have a significant impact on the sensitivity of the detection system.The results showed that the detection system had a great sensitivity when the concentration of 4-MBA and p H were 5×10-6 mol·L-1 and 9,respectively.Under the optimal condition,the Cr3+ion could induced detection system changes from yellow to blue-violet,the UV detection limit is 9×10-6 mol·L-1.The colorimetric detection limit can reach to 1×10-5 mol·L-1.There is a non-linear relationship between the signal response and the concentration of Cr3+ions from 1×10-5 mol·L-1 to 5×10-4 mol·L-1,with a correlation coefficient of 0.993.At the same time,the system has good anti-interference performance,successfully detecting Cr3+ion simulated samples,with recoveries of 88.2%to 112.1%.The system can rapidly and sensitively detect Cr3+ions in aqueous solutions,and has a good application prospect.（2）Synthesis of thiomalate acid（MSA）functionalized Au@Ag NPs and its detection of Cr3+ions.This part of the study constructed a MSA-Au@Ag NPs visual detection system for Cr3+ions based on the preparation of Au@Ag NPs in the previous chapter,using MSA as a functional reagent.The optimal concentration of MSA and the optimal p H,while conducting sensitivity experiments and interference experiments.The research results show that the concentration of MSA and p H have important effects on the detection system.When the concentration of MSA is 1×10-6 mol·L-1 and the p H is 10,the UV detection limit is 1×10-5mol·L-1 and the visual detection limit is 1.4×10-5 mol·L-1.In the range 1.4×10-5 mol·L-1 to8×10-5 mol·L-1,there is a non-linear relationship between the signal response and the concentration of Cr3+ions,with a correlation coefficient of 0.996.The system has successfully detected simulated samples of Cr3+ions with a recovery of 92.4%-113.7%.（3）Construction of TMB,Na2S2O3 and triangular silver nanoparticles systems and its Cu2+ion detection.This study constructs a system of Cu2+ion detection in aqueous solution based on TMB,Na2S2O3,and triangular silver nanoparticles.In this system,under the presence of Na2S2O3,Cu2+can etch silver nanoparticles,and based on this mechanism,detection of Cu2+ions is achieved;In addition,further research was conducted to prepare TMB functionalized silver nanoparticles,and through the above mechanism,a detection system for silver nanoparticles Cu2+ions was constructed.This study investigated the optimal volume ratio of functionalized silver nanoparticles,the optimal concentration of TMB and Na2S2O3,and the sensitivity of the system.The results showed that the detection system had a great sensitivity when the concentration of solution proportion,Na2S2O3 and TMB were 20%,5×10-4 mol·L-1 and 5×10-5 mol·L-1,respectively.The detection limit is 2×10-6 mol·L-1。... |
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