| Under the condition of 0.67 mmol/L HCl and water bath 60℃,the speed of reaction what H2O2 and HAuCl4 generate gold nanoparticles is slow,and irregular gold nanoparticles were obtain by the catalytic effect of nanoparticle.The producted gold nanoparticles have a strong Resonance Rayleigh scattering(RRS)peak at 370 nm.Victoria blue B(VBB)and rhodamine S(RhS)have a strong SERS peak at 1612 cm-1 and 1645 cm-1 as surface-enhanced resonance Raman scattering(SERS)probe.Gold nanoparticles which was synthesized by NaBH4(AuNPB),and the increased RRS intensity I370nm and SERS intensity I1612 cm-1 and I1645 cm-1 are linearly with the concentration of AuNPB over 0.038-76ng/mL,19-285ng/mL,3.8-456ng/mL respectively.In this paper,gold nanorods(AuNR),silver nanoparticles(AgNP),nanoplatinum(PtNP),nanopalladium(PdNP)had catalytic activity to HAuCl4-H2O2,glucose-HAuCl4,hydroxylamine hydrochloride-HAuCl4,AgNO3-H2O2 particles reaction.In pH 7.0 Na2HPO4-NaH2PO4 buffer solution and 0.1mol/L NaCl solution,gold nanoparticles which was synthesized by sodium citrate(AuNPc)were modified by DNA to prepare stable AuNPc-DNA in solution.Upon addition of Hg(Ⅱ),the appetency of DNA and AuNPc was weak because DNA combined with Hg(Ⅱ)to form T-Hg-T structure,and released AuNPc to aggregate under the effect of NaCl,which exhibited a strong RRS peak at 370 nm.With the increase of Hg(Ⅱ)concentration,the RRS peak increased due to forming more T-Hg-T structure.The increased RRS intensity responds linearly with the concentration of Hg(Ⅱ)over 8.3-66.7nmol/L.AuNPc-DNA probe of the aptamer reaction solution had strong catalytic activity to HAuCl4-H2O2 particles reaction.With the increase of Hg(Ⅱ)concentration,the concentration of AuNPc-DNA probe was decreased,and lead to weak catalytic activity.The decreased RRS intensity responds linearly with the concentration of Hg(Ⅱ)over 0.8-30nmol/L.Adding VBB and RhS as SERS probe,the SERS intensity I1612 cm-1 and I1645 cm-1 responds linearly with the concentration of Hg(Ⅱ)over 17-250,17-167nmol/L.According this.we can establish a sensitive,convenient and new quantitative analysis method for detection of Hg(Ⅱ)by RRS and SERS.Gold nanoparticles(AuNP)were modified by the DNA to prepare Au-DNA probe for detection As(Ⅲ).In pH 8.0 HEPES buffer solution containing 50 mmol/L NaCl,rhodamine 6G(Rh6G)molecules were adsorbed on the Au-DNA substrate,and exhibited a strong surface enhanced Raman scattering peak(SERS)at 1358 cm-1.Upon addition of As(Ⅲ),it reacted with the Au-DNA probe to form a stable As-DNA complex and released AuNP to aggregate under the effect of NaCl.With the increase of As(Ⅲ)concentration,the SERS peak decreased at 1358 cm-1 due to forming more AuNP aggregates.The decreased SERS intensity responds linearly with the concentration of As(Ⅲ)over 0.288-23.04 ng/mL,with a detection limit of 0.1 ng/mL.Au-DNA probe of the aptamer reaction solution had strong catalytic activity to HAuCl4-H2O2 particles reaction.Victoria 4R(VB4R)molecules were adsorbed on the catalytic reaction products gold nanoparticles(AuNP)sol substrate exhibited a strong surface enhanced Raman scattering peak(SERS)at 1612 cm-1.With the increase of As(Ⅲ)concentration,the concentration of Au-DNA probe is decrease lead to the catalytic activity weaker.The decreased SERS intensity responds linearly with the concentration of As(Ⅲ)over 0.15-2.611ng/mL,with a detection limit of 0.017 ng/mL.In pH 8.0 Tris-HCl buffer solution containing 6.7mmol/LNaCl,DNAzyme catalytic stranded hybridize with substrate stranded to form double-stranded DNA(dsDNA).AuNPc were aggregated to the AuNPc aggregations which exhibited a strong RRS peak at 370 nm.Upon addition of Pb(Ⅱ),the substrate chain of dsDNA could be cracked catalytically by Pb(Ⅱ)to produce a short single-stranded DNA(DNA).DNA were adsorbed on the AuNPc surface to form stable AuNPc-DNA.With the increase of Pb(Ⅱ)concentration,the concentration of AuNPc-DNA were increased and stronger catalytic activity.The increased RRS intensity at 370nm responds linearly with the concentration of Pb(Ⅱ)over 16.7-666.7nmol/L.Adding VBB and RhS as SERS probe,the SERS intensity I1612 cm-1 and I1645cm-1 responds linearly with the concentration of Pb(Ⅱ)over 50-500 nmol/L.Base on this establish a sensitive new quantitative analysis methods for detection of Pb(Ⅱ)used DNA enzymatic hydrolysis reaction combine with nanogold catalytic system. |
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