Sensitive and Selective Detection of Mercury Ions in Aqueous Media Using an Oligonucleotide-functionalized Nanosensor and SERS Chip

摘要

A surface-enhanced Raman scattering (SERS) platform for the selective trace analysis of Hg~(2+) ions was reported, based on poly-thymine (T) aptamer/2-naphthalenethiol (2-NT)-modified gold nanoparticles (AuNPs), which was an oligonucleotide-functionalized nanosensor and SERS chip. 2-NT was used as a Raman reporter, and T aptamer could form a T-Hg~(2+)-T structure with Hg~(2+) ions making an SERS nanosensor absorbed to the SERS chip. The optimum concentrations of DNA and 2-NT were obtained. An average of 960 DNA molecules attached to each AuNP were measured. The limit of detection (LOD) was 1.0 ppt (1.0 × 10~(?12) 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, a simple sample pretreatment, a green solution and reducing false positives. Furthermore, the nanosensor was used for the determination of trace Hg~(2+) in the water of a lake; a reliable result was obtained accurately.