| The rapid development of economy and technology brings convenience to human life,but also produces a series of environmental pollution problems.The pollution of explosives(e.g.,2,4,6-trinitrotoluene,TNT)and heavy metal ions(e.g.,Hg2+)causes serious destruction to human health.Therefore,the development of efficient,sensitive and specific detection methods is of significance for the analysis of pollutants in the environment.Compared to the traditional Raman scattering,surface-enhanced Raman Scattering(SERS)plays an important role in the field of analysis and detection because of its high sensitivity,good specificity and simple detection method.In recent years,SERS substrates of silicon-based nanohybrids(e.g.,silver nanoparticles modified silicon,gold nanoparticles modified silicon nanowire arrays,etc.)exhibit obvious SERS enhancement effect and good signal reproducibility,which have attracted researchers’ wide attention.In this paper,two kinds of SERS chips are constructed by using silver nanoparticles-decorated silicon wafer(Ag NPs@Si)as the SERS substrate.The obtained chips feature good SERS enhancement,signal reproducibility and chemical stability,which are thus available for sensitive and specific detection of pollutants in the environment.The main contents are summarized as follows:The first part: By using Ag NPs@Si modified by p-aminobenzenethiol(PABT)molecules,a silicon-based SERS chip(PABT-Ag NPs@Si)is constructed for TNT detection.In the absence of TNT,the Raman signal of PABT is undetectable on the chip.In the presence of TNT,the charge transfer between PABT and TNT would lead to the formation of PABT-TNT complex,leading to the enhancement the Raman signal of PABT.As thus,TNT detection is readily realized through detecting the change of Raman intensity,with the detection limit of 1 p M.In addition,the silicon-based SERS chip has good selectivity.Furthermore,the chip coupled with handheld Raman instruments is ready for the on-site detection of TNT residues in the environmental systems(e.g.,lake water,liquor,soil and envelope paper).The second part: By using tea polyphenols as a reductant,the nanoparticles featuring the core(silver,Ag)-shell(gold,Au)structure are in situ growth on the surface of Ag NPs@Si substrate;meanwhile,the internal standard molecule(4-mercaptopyridine,4-Mpy)is embedded in the nanostructure,thus producing the “core(Ag)-molecule(4-Mpy)-shell(Au)” structured SERS chip(Core-molecule-shell structure decorated silicon,CMS@Si).The chip has good stability and maintains good reproducibility in relatively complex environments(e.g,15% H2O2,13% HNO3,108 CFU m L-1 bacteria,and continuous oscillation in PBS buffer solution for 12 days).In addition,the chip combined with DNA chain is capable of specific identification and quantitative analysis for Hg2+. |
