Acid-base chemistry at the single ion limit.

Chemical Science
Vignesh Sundaresan, Paul W Bohn

Abstract

We present the results of acid-base experiments performed at the single ion (H+ or OH-) limit in ∼6 aL volume nanopores incorporating electrochemical zero-mode waveguides (E-ZMWs). At pH 3 each E-ZMW nanopore contains ca. 3600H+ ions, and application of a negative electrochemical potential to the gold working electrode/optical cladding layer reduces H+ to H2, thereby depleting H+ and increasing the local pH within the nanopore. The change in pH was quantified by tracking the intensity of fluorescein, a pH-responsive fluorophore whose intensity increases with pH. This behavior was translated to the single ion limit by changing the initial pH of the electrolyte solution to pH 6, at which the average pore occupancy 〈n〉pore ∼3.6H+/nanopore. Application of an electrochemical potential sufficiently negative to change the local pH to pH 7 reduces the proton nanopore occupancy to 〈n〉pore ∼0.36H+/nanopore, demonstrating that the approach is sensitive to single H+ manipulations, as evidenced by clear potential-dependent changes in fluorescein emission intensity. In addition, at high overpotential, the observed fluorescence intensity exceeded the value predicted from the fluorescence intensity-pH calibration, an observation attributed to ...Continue Reading

References

Feb 24, 2001·Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy·X Y ZhengT Ogawa
Aug 21, 2013·Langmuir : the ACS Journal of Surfaces and Colloids·Long Luo, Henry S White
Mar 20, 2014·Journal of the American Chemical Society·Byung-Kwon KimAllen J Bard
Jan 24, 2015·Journal of the American Chemical Society·Byung-Kwon KimAllen J Bard
Aug 19, 2015·The Journal of Physical Chemistry Letters·Qianjin ChenHenry S White
Nov 29, 2016·Faraday Discussions·Thom HersbachKatharina Krischer
Nov 29, 2016·Faraday Discussions·Justin GoodingSerge Lemay
Nov 29, 2016·Faraday Discussions·Tim AlbrechtMartin Edwards
Oct 24, 2017·Journal of the American Chemical Society·Cameron L BentleyPatrick R Unwin
Feb 24, 2018·Journal of the American Chemical Society·Sean R GermanHenry S White
May 23, 2018·Proceedings of the National Academy of Sciences of the United States of America·Rui HaoBo Zhang
Jul 12, 2018·Journal of the American Chemical Society·Kevin WonnerKristina Tschulik
Sep 20, 2018·Faraday Discussions·Hassan AlzahraniYilun Ying
Nov 6, 2018·Journal of the American Chemical Society·Lane A Baker
Nov 30, 2018·Journal of the American Chemical Society·Cameron L BentleyPatrick R Unwin
Apr 25, 2019·Annual Review of Analytical Chemistry·Fato Tano PatriceYi-Tao Long

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Citations

Feb 25, 2021·Chemical Society Reviews·Jasper P FriedJames R Yates

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Methods Mentioned

BETA
electrochemical cell microscopy
fluorescence microscopy

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