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Assessment of the efficiency of density sucrose gradient centrifugation for the separation of gold nanoparticles by spICP-MS



Monique E. Johnson, Antonio R. Montoro Bustos, Michael R. Winchester


The suitability of rate zonal density sucrose gradient centrifugation separation is explored for the purification/separation of three gold nanoparticles (AuNPs) mixtures (Mixture 1: 30 nm, 60 nm, and 100 nm; Mixture 2: 20 nm, 50 nm, and 100 nm; Mixture 3: 30 nm, 80 nm, and 150 nm) at environmentally relevant concentrations. At these extremely low concentrations, conventional analytical techniques cannot be applied toward quantitative analysis and size characterization after centrifugation. In this context, single particle inductively coupled plasma mass spectrometry (spICP-MS), in conjunction with total Au conventional ICP-MS analysis, was implemented to assess the efficiency of density sucrose gradient centrifugation. This methodology has been implemented to properly address size characterization, and quantification, as well as the contribution of each component of several mixtures in terms of size and particle number concentration across the sucrose layers. spICP-MS size resolution and number quantification capabilities were used to examine the ability of density sucrose gradient centrifugation to physically separate the components of two types of mixtures: “unresolved” and “resolved.” In addition, for each mixture, equal particle number concentration and equal Au mass fraction conditions for the three different constituent sizes were tested as parameters to investigate the efficacy of the separation. In this work, total Au analysis by conventional ICP-MS has been utilized as a prescreening tool for the preceding characterization and optimization of density sucrose gradient centrifugation as well as for the internal validation of the proposed methodology. Afterwards, spICP-MS sizing and counting results corroborated a lack of separation of the components of the “unresolved” Mixture 1 and 2, revealing the cohabitation of the two smaller AuNPs. Finally, a far superior separation for “resolved” Mixture 3 under short centrifugation time (20 min) was proven by spICP-
Analytical and Bioanalytical Chemistry


density sucrose gradient centrifugation, ICP-MS, spICP-MS, gold nanoparticles


Johnson, M. , Montoro, A. and Winchester, M. (2016), Assessment of the efficiency of density sucrose gradient centrifugation for the separation of gold nanoparticles by spICP-MS, Analytical and Bioanalytical Chemistry, [online], (Accessed April 24, 2024)
Created August 8, 2016, Updated November 10, 2018