Mercuric ions induced aggregation of gold nanoparticles as investigated by localized surface plasmon resonance light scattering and dynamic light scattering techniques

With the development of nanosciences, both localized surface plasmon resonance light scattering （LSPR-LS） and dynamic light scattering （DLS） techniques have been widely used for quantitative purposes with high sensitivity. In this contribution, we make a comparison of the two light scattering techniques by employing gold nanoparticles （AuNPs） aggregation induced by mercuric ions. It was found that citrate-stabilized AuNPs got aggregated in aqueous medium in the presence of mercuric ions through a chelation process, resulting in greatly enhanced LSPR-LS signals and increased hydrodynamic diameter. The enhanced LSPR-LS intensity （A/） is proportional to the concentration of mercuric ions in the range of 0.4-2.5 laM following the linear regression equation of A/= -84.7＋516.4c, with the correlation coefficient of 0.983 （n = 6） and the limit of determi- nation （3o-） about 0.10 gM. On the other hand, the increased hydrodynamic diameter can be identified by the DLS signals only with a concentration of Hg2＋ in the range of 1.0-2.5 gM, and a linear relationship between the average hydrodynamic diame- ters of the resulted aggregates and the concentration of Hg2＋ can be expressed as d = -6.16 ＋ 45.9c with the correlation coeffi- cient of 0.994. In such case, LSPR-LS signals were further applied to the selective determination of mercuric ions in lake water samples with high sensitivity and simple operation.

With the development of nanosciences, both localized surface plasmon resonance light scattering (LSPR-LS) and dynamic light scattering (DLS) techniques have been widely used for quantitative purposes with high sensitivity. In this contribution, we make a comparison of the two light scattering techniques by employing gold nanoparticles (AuNPs) aggregation induced by mercuric ions. It was found that citrate-stabilized AuNPs got aggregated in aqueous medium in the presence of mercuric ions through a chelation process, resulting in greatly enhanced LSPR-LS signals and increased hydrodynamic diameter. The enhanced LSPR-LS intensity ( I) is proportional to the concentration of mercuric ions in the range of 0.4-2.5 M following the linear regression equation of I = 84.7+516.4c, with the correlation coefficient of 0.983 (n = 6) and the limit of determination (3 ) about 0.10 M. On the other hand, the increased hydrodynamic diameter can be identified by the DLS signals only with a concentration of Hg 2+ in the range of 1.0-2.5 M, and a linear relationship between the average hydrodynamic diameters of the resulted aggregates and the concentration of Hg 2+ can be expressed as d = 6.16 + 45.9c with the correlation coefficient of 0.994. In such case, LSPR-LS signals were further applied to the selective determination of mercuric ions in lake water samples with high sensitivity and simple operation.