Simultaneous Sensitive Detection of Lead(II), Mercury(II) and Silver Ions Using a New Nucleic Acid-Based Fluorescence Sensor.

Yuan Deng,Yinran Chen,Xiaodong Zhou

doi:10.17344/acsi.2017.3620

Abstract

A new nucleic acid-based fluorescence sensor is reported for simultaneous detection of Pb2+, Ag+, and Hg2+ based on the specific catalytic activity of Pb2+ for a particular DNAzyme, specific regulation of Ag+ on "C-Ag+-C" complex, and stable complex formed by Hg2+ and rhodamine B isothiocyanate (RBITC). Three fluorescence dyes, aminomethylcoumarin acetic acid (AMCA), 5-carboxyfluorescein (FAM), and RBITC, were modified on the probes and served as fluorescent donors. Upon DNA interaction with these metal ions and AuNP fluorescence quenching effect on the fluorescence dyes,the fluorescencerecovery of RBITC and the fluorescencequenching of AMCA and FAM were monitored to detect Hg2+, Pb2+, and Ag+, separately, without the need of using any masking reagents. This sensor exhibited high sensitivity and selectivity. The limit of detection (LOD) is 0.48 nM for Pb2+, 0.23 nM for Ag+, and 0.17 nM for Hg2+. Finally, this sensor was successfully applied for simultaneous detection of Pb2+, Ag+, and Hg2+ in real sample.

Highlights

With the ever increasing pollution from modern industry, heavy metal contaminants have posed severe adverse effects on human health and ecosystems due to their high and persistent toxicities.[1,2] it is quite necessary and urgent to rapidly and accurately detect these metal ions
A new nucleic acid-based fluorescence sensor is reported for simultaneous detection of Pb2+, Ag+, and Hg2+ based on the specific catalytic activity of Pb2+ for a particular DNAzyme, specific regulation of Ag+ on “C-Ag+-C” complex, and stable complex formed by Hg2+ and rhodamine B isothiocyanate (RBITC)
AMCA was specially designed to label at one end of the substrate strand of 8-17 DNAzyme, and the other end was combined with Au nanoparticles (AuNPs), emitting fluorescence signal at 450 nm

Summary

Introduction

With the ever increasing pollution from modern industry, heavy metal contaminants have posed severe adverse effects on human health and ecosystems due to their high and persistent toxicities.[1,2] it is quite necessary and urgent to rapidly and accurately detect these metal ions. Traditional methods, such as atomic absorption spectrometry (AAS),[3] inductively coupled plasma mass spectrometry (ICP-MS),[4] and anodic stripping voltammetry (ASV),[5] have high sensitivity and selectivity but require specialized instrumentation and extensive sample pretreatment processes which limit their applications for in situ analysis.[6,7]. Fluorescence spectra were used at trace level due to its high sensitivity

Experimental

Results and Discussion

Conclusions