Quantitative analysis of trace Pb(II) by a DNAzyme cracking-rhodamine 6G SERRS probe on AucoreAgshell nanosol substrate

In pH 7.2 Tris-HCl buffer solution containing 0.09 mol/L NaCl at 80 degrees C, the single-stranded substrate DNA hybrids with the enzyme DNA to form double-stranded DNA (dsDNA). The substrate chain of dsDNA could be cracked catalytically by Pb2+ to produce a short single-stranded DNA (ssDNA) that adsorbed on the AucoreAgshell nanoparticle (Au/AgNP) surface to form stable Au/AgNP-ssDNA conjugate to prevent aggregation by NaCl, and it combined with rhodamine 6G (RhG) to form RhG-Au/AgNP-ssDNA probe that exhibited a strong surface-enhanced resonance Raman scattering (SERRS) peak at 1510 cm(-1). With the increase of Pb2+ concentration, the SERRS peak increased linearly due to the more RhG-Au/AgNP-ssDNA probe forming. Under the selected conditions, the increased SERRS intensity Delta I was linear to Pb2+ concentration in the range of 5.0 x 10(-8)-7.0 x 10(-7) mol/L, with a detection limit of 7 x 10(-9) mol/L Pb2+. (C) 2014 Elsevier B.V. All rights reserved.