一个检测痕量汞离子的鱼精DNA修饰纳米金共振散射光谱法

在pH 7.0 Tris-HCl缓冲溶液及0.017 mol.L-1NaCl介质中,鲱鱼精DNA与10 nm的金纳米粒子形成较稳定的结合物使得金纳米粒子不聚集,体系的散射信号较弱。当有Hg2+存在时,DNA与Hg2+形成更稳定的DNA-Hg2+结合物,金纳米粒子聚集导致572 nm处的共振散射峰增强。在3.87μg.mL-1金纳米粒子-11.7μg.mL-1DNA-pH 7.0~17 mmol.L-1NaCl条件下,Hg2+浓度c在3.3~3 333.3 nmol.L-1范围内与572 nm处的共振散射强度增强值ΔI572 nm成良好线性关系,其回归方程、相关系数、检出限分别为ΔI572 nm=0.019c+5.0,0.999 1,2.5 nmol.L-1。该法用于水样分析,结果与冷原子吸收光谱法一致,相对标准偏差为5.1%。

Resonance Scattering Detection of Trace Hg~(2+) Using Herring Sperm NDA Modified Nanogold

In pH 7.0 tris-HCl buffer solutions and in the presence of 0.017 mol·L~(-1) NaCl,herring sperm DNA was combined with gold nanoparticles in size of 10 nm to form stable complex,and the NaCl did not cause the aggregation of the gold nanopartielea.Upon addition of Hg~(2+),that reacted with DNA to form more stable complex of Hg~(2+)-DNA,and the gold nanoparticles aggregated to from larger nanogold clusters that led to considerable enhancement of the resonance scattering intensity at 572 nm enhanced considerably.The effect of GN concentration,DNA concentration,NaCl concentration,incubation time,and temperature,and ultrasonic irradiation was considered respectively,the conditions of 3.87 μg·mL~(-1) GN,11.7 μg·mL~(-1) DNA,pH 7.0 Tris-HC1 buffer solutions,17 mmol·L~(-1) NaCl,and incubation 10 min at 37℃ under the ultrasonic irradiation were chosen for use.Under the conditions,the enhanced resonance scattering intensity at 572 nm was linear to the Hg~(2+) concentration in the range of 3.3-3 333.3 nmol·L~(-1),with regress equation of △I_(572nm)=0.019c+5.0,coefficient of 0.999 1,and a detection limit of 2.5 nmol·L~(-1) Hg~(2+).Results of interference tests showed that 30 μmol·L~(-1) Mn~(2+),33 μmol·L~(-1) Mg~(2+) and Zn~(2+),100 μmol·L~(-1) Cd~(2+),200 μmol·L~(-1) Fe~(3+),and 420 μmol·L~(-1) Mo~(6+),Pb~(2+) and Cu~(2+) did not interfered with the determination of 0.33 μmol·L~(-1) Hg~(2+).That is,this resonance scattering spectral assay is of good selectivity.This assay was applied to the detection of Hg(Ⅱ)in water sample,with a relative standard deviation of 5.1%,and the results were in agreement with that of the cool vapor atomic absorption spectrophotometry.