A sensitive assay of mercury using fluorescence correlation spectroscopy of gold nanoparticles.
We described a new and sensitive method for the determination of mercury ions (Hg(2+) ) on the basis of fluorescence correlation spectroscopy (FCS) and recognition of oligonucleotides. In this assay, 30-nm gold nanoparticles (GNPs) were modified with oligonucleotides containing thymine bases (T) as fluorescent probes, and the principle of this assay was based on the specific binding of Hg(2+) by two DNA thymine bases. When two GNPs labelled with different oligonucleotides were mixed with a sample containing Hg(2+), the T-Hg(2+)-T binding reaction should cause GNPs to form dimers (or oligomers), which would lead to a significant increase in the characteristic diffusion time of GNPs in the detection volume. The FCS method is a single molecule detection method and can sensitively detect the change in the characteristic diffusion time of GNPs before and after binding reactions. The quantitative analysis was performed according to the relation between the change in the characteristic diffusion time of GNPs and the concentration of Hg(2+). Under optimal conditions, the linear range of this method was from 0.3 nM to 100 nM, and the detection limit was 0.14 nM for Hg(2+). This new method was successfully applied for direct determination of Hg(2+) levels in water and cosmetics samples.
School of Chemistry & Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China.
Zhancheng
Z
Xu
School of Chemistry & Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China.
Tao
T
Lan
School of Chemistry & Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China.
Xiangyi
X
Huang
School of Chemistry & Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China.
Chaoqing
C
Dong
School of Chemistry & Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China.
Jicun
J
Ren
D002138:Calibration; D003358:Cosmetics / Q000032:analysis; D005456:Fluorescent Dyes / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D057230:Limit of Detection; D008628:Mercury / Q000032:analysis* / Q000378:metabolism; D053768:Metal Nanoparticles / Q000737:chemistry*; D009841:Oligonucleotides / Q000737:chemistry; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013941:Thymine / Q000737:chemistry / Q000378:metabolism; D014867:Water / Q000032:analysis
D003358:Cosmetics; D005456:Fluorescent Dyes; D009841:Oligonucleotides; D014867:Water; D006046:Gold; D008628:Mercury; D013941:Thymine
Fluorescence correlation spectroscopy; Gold nanoparticles; Mercury; Oligonucleotides