Single Organic Droplet Collision Voltammogram via Electron Transfer Coupled Ion Transfer

Cheng Liu, Pekka Peljo, Xinjian Huang, Wenxue Cheng, Lishi Wang*, Haiqiang Deng

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

20 Citations (Scopus)


Single-emulsion toluene oil droplets (femtoliter) containing a hydrophobic redox probe that are dispersed in water stochastically collide with an ultramicroelectrode (UME). The fast-scan cyclic voltammetry (FSCV) or Fourier-transformed sinusoidal voltammetry (FTSV) is applied: the UME was scanned with a fast, repetitive triangular, or sinusoidal potential, and its current in time/frequency domains were monitored. The electron transfer at the UME/oil interface is coupled with ion transfer at the oil/water interface. Thus, the obtained transient voltammograms of a myriad of ions were used to estimate thermodynamics of ion transfer at the toluene/water interface. Additionally, the single-droplet voltammogram combined with finite element simulations reveal the droplet's size and shape distributions. Four collision mechanisms with new physical insights were also uncovered via comprehensive analysis of phase angle in the frequency domain, time domain FSCVs, and finite element simulations.

Original languageEnglish
Pages (from-to)9284-9291
Number of pages8
JournalAnalytical Chemistry
Issue number17
Publication statusPublished - 5 Sep 2017
MoE publication typeA1 Journal article-refereed


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