Alligrant TM, Anderson MJ, Dasari R, Stevenson KJ, Crooks RM. Single nanoparticle collisions at microfluidic microband electrodes: the effect of electrode material and mass transfer.
LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014;
30:13462-13469. [PMID:
25360826 DOI:
10.1021/la503628h]
[Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report on the effect of convection on electrochemically active collisions between individual Pt nanoparticles (PtNPs) and Hg and Au electrodes. Compared to standard electrochemical cells utilizing Hg and Au ultramicroelectrodes (UMEs) used in previous studies of electrocatalytic amplification, microelectrochemical devices offer two major advantages. First, the PtNP limit of detection (0.084 pM) is ∼8 times lower than the lowest concentration measured using UMEs. Second, convection enhances the mass transfer of PtNPs to the electrode surface, which enhances the collision frequency from ∼0.02 pM(-1) s(-1) on UMEs to ∼0.07 pM(-1) s(-1) in microelectrochemical devices. We also show that the size of PtNPs can be measured in flowing systems using data from collision experiments and then validate this finding using multiphysics simulations.
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