| The heavy mental contaminant has been one of the most serious environmental issues due to its high toxicity and accumulation.Pb2+and Cr3+have a serious hazard to the health of human.For instance,Pb2+can lead to intelligence development,endocrine disorders,anemia,mental confusion and so on.Cr3+is an essential trace element for the human body.It plays an important role on the metabolism of fats,proteins,nucleic acids,and so on.However,it can only maintain a certain amount in the body,and when the concentration is too high,it will be nausea,vomiting,ulcers,and even can cause cancer.Therefore,it is impressively significant to establish a simple and rapid method for the determination of heavy metal ions.Noble metal nanomaterials are unique and different with macroscopic matter on the structure and properties,which attracts more and more attention in the field of LSPR sensor,and has been used as a probe to detect metal ions by many scholars.In the first part,we develop the Pb2+sensor based on the LSPR properties of gold nanoparticles.Firstly,gold nanoparticles?Au NPs?were synthesized by the sodium citrate reduction method.Then,the AuNPs were self-assembled on transparent indium tin oxide?ITO?glass using poly dimethyl diallyl ammonium chloride?PDDA?as a linker and high temperature calcination to obtain pure gold arrays on the ITO surface?ITO/AuNPs?.Glutathione?GSH?was modified onto the surface of gold nanoparticles by Au-S bonds to obtain functionalized sensor probe?ITO/AuNPs/GSH?.Under the condition of pH 7.5,the strong chelation of Pb2+with glutathione caused a large change in the surface refractive index of the AuNPs,resulting in the red shift of local surface plasmon resonance peak.This probe can make it possible to high sensitivity and high selective detection of Pb2+.The red shift of the LSPR peak is proportional to the concentration of Pb2+in the range of 1.0×10-10to 1.0×10-5M,with a detection limit of 5x10-11M.It has been successfully used for the detection of Pb2+in real samples.In the second part,the Cr3+electrochemical sensor based on the amplification effect of silver nanoparticles was investigated.Firstly,ITO/Au NPs/MSA was obtained by the same method as in the first part.Under the condition of pH 4.5,it can selectively react with Cr3+,and the detectable chromium ion concentration was in the range of 1.0×10-6-1.0×10-3M.Then,bovine serum albumin?BSA?was introduced as the second complexant which improved the sensitivity.The LSPR red shift of the sensor showed a good linear relationship with the chromium ion concentration in the range of 1.0×10-8–1.0×10-3M.In order to further improve the detection sensitivity,we also selected MSA-AgNPs as the second complexant and combined with the technique of electrochemical determination.The results showed that a calibration curve from1.0×10-10-1.0×10-8M Cr3+was obtained under the optimization condition,which is expected to be applied to the real sample detection. |
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