SERS Detection Of Trace Heavy Metal Ions In Seawater

Mercury ion(Hg²⁺)and lead ion(Pb²⁺)are very harmful heavy metal ions to human bodies.Even at ultra-low concentration,they can cause a variety of hazards to human health.Mercury and lead in water can enter human bodies through food chain,especially aquatic products.Heavy metal ions in seawater can also cause huge damage to human bodies through the enrichment of food chain.Therefore,the establishment of a specific,sensitive and low detection limit?LOD?heavy metal ion detection method in the complex environment of seawater plays a huge role of human body and even the whole biological chain.In this paper,three methods of surface enhanced Raman?SERS?technique are introduced for the trace detection of mercury and lead ions in seawater.The test results are much better than traditional Hg²⁺ions detection methods,such as 8×10^-1111 g/mL by ELISA,9×10^-1010 g/mL by CA-AFS,1.6×10^-66 g/mL by HGAAS,4×10^-10g/mL by ETAAS.Compared with other methods,our results have excellent sensitivity to Hg²⁺and Pb²⁺detection.?1?Preparation of solid substrate for SERS chipLike humans'fingerprints,each substance has its own unique Raman spectra,so SERS technology has been widely used in many fields to achieve the detection of chemical and biological molecules.In the application of SERS technology,a base with reasonable structure and stable performance plays a vital role.Therefore,the substrates with different structural properties were discussed and their properties were examined.?2?Construction and application of SERS solid state chip sensor for mercury ion detectionA surface-enhanced Raman scattering platform for the selective trace analysis of Hg²⁺ions was reported based on ploy-thymine?T?aptamer/2-naphthalenethiol?2-NT?-modified gold nanoparticles?AuNPs? which was Oligonucleotide-Functionalized nanosensor and SERS chip.2-NT was used as a Raman reporter and T aptamer can form a T-Hg²⁺-T structure with Hg²⁺ions,making SERS nanosensor absorbed to the SERS chip.The optimum concentration of DNA and 2-NT was obtained.An average of 960 DNA molecules attached to each AuNP were measured.The limit of detection?LOD?is 1.0 ppt?1.0×10^-1212 g/mL?,which is far below the limit of 10.0 ppb for drinking water stipulated by the World Health Organization.The sensor has the advantages of low detection cost,simple sample pretreatment,green solution and reducing false positive.Furthermore,the nanosensor was used for the determination of trace Hg²⁺in the water of lake,and a reliable result has been obtained accurately.?3?Simultaneous detection of mercury and lead ions by SERS solid-state chip sensor and construction of new molecular logic gate circuitA conceptually new class of DNA logic gates for Hg²⁺and Pb²⁺ions simultaneous detection has been constructed based on the activity of DNAzyme dependent on metal ions.For sensitive and specific detection of Hg²⁺and Pb²⁺ions,we demonstrate a surface-enhanced Raman scattering-active platform by employing the oligonucleotide-functionalized and gold coated polystyrene microspheres?PSMPs?.In this work,Hg²⁺and Pb²⁺were used as the input,and the SERS signals were the output.Hg²⁺ions were captured by a mismatched T-Hg-T bridge.Pb²⁺ions were bound to 8-17 DNAzyme to break the cleavage substrate.The LOD of Hg²⁺is0.1 nM and Pb²⁺is 1.0 nM,which is far below the limit of 10.0 ppb?31 nM?and 10.0ppm?3.02×10⁴ nM?for drinking water stipulated by the World Health Organization.Additionally,this system has the potential to be ideal candidates for intelligent DNA calculator design applications.Furthermore,the designed strategy could be extended to other multiplex metal ions that can be combined with DNA molecules,and can be applied to many other fields such as environmental detection,toxin detection and liquid analysis.