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Robinson DA, Kondajji AM, Castañeda AD, et al. Addressing Colloidal Stability for Unambiguous Electroanalysis of Single Nanoparticle Impacts. J Phys Chem Lett. 2016;7(13):2512-7doi: 10.1021/acs.jpclett.6b01131.
Robinson, D. A., Kondajji, A. M., Castañeda, A. D., Dasari, R., Crooks, R. M., & Stevenson, K. J. (2016). Addressing Colloidal Stability for Unambiguous Electroanalysis of Single Nanoparticle Impacts. The journal of physical chemistry letters, 7(13), 2512-7. https://doi.org/10.1021/acs.jpclett.6b01131
Robinson, Donald A, et al. "Addressing Colloidal Stability for Unambiguous Electroanalysis of Single Nanoparticle Impacts." The journal of physical chemistry letters vol. 7,13 (2016): 2512-7. doi: https://doi.org/10.1021/acs.jpclett.6b01131
Robinson DA, Kondajji AM, Castañeda AD, Dasari R, Crooks RM, Stevenson KJ. Addressing Colloidal Stability for Unambiguous Electroanalysis of Single Nanoparticle Impacts. J Phys Chem Lett. 2016 Jul 07;7(13):2512-7. doi: 10.1021/acs.jpclett.6b01131. Epub 2016 Jun 21. PMID: 27306603.
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J Phys Chem Lett. 2016 Jul 07;7(13):2512-7. doi: 10.1021/acs.jpclett.6b01131. Epub 2016 Jun 21.

Addressing Colloidal Stability for Unambiguous Electroanalysis of Single Nanoparticle Impacts.

The journal of physical chemistry letters

Donald A Robinson, Aditya M Kondajji, Alma D Castañeda, Radhika Dasari, Richard M Crooks, Keith J Stevenson

Affiliations

  1. Department of Chemistry, Center for Nano- and Molecular Science, and Center for Electrochemistry, University of Texas at Austin , Austin, Texas 78712, United States.

PMID: 27306603 DOI: 10.1021/acs.jpclett.6b01131

Abstract

Herein the problem of colloidal instability on electrochemically detected nanoparticle (NP) collisions with a Hg ultramicroelectrode (UME) by electrocatalytic amplification is addressed. NP tracking analysis (NTA) shows that rapid aggregation occurs in solution after diluting citrate-stabilized Pt NPs with hydrazine/phosphate buffers of net ionic strength greater than 70 mM. Colloidal stability improves by lowering the ionic strength, indicating that aggregation processes were strongly affected by charge screening of the NP double layer interactions at high cation concentrations. For the system of lowest ionic strength, the overwhelming majority of observed electrocatalytic current signals represent single NP/electrode impacts, as confirmed by NTA kinetic monitoring. NP diffusion coefficients determined by NTA and NP impact electroanalysis are in excellent agreement for the stable colloids, which signifies that the sticking probability of Pt NPs interacting with Hg is unity and that the observed NP impact rate agrees with the expected steady-state diffusive flux expression for the spherical cap Hg UME.

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