TY - JOUR
T1 - GABA Detection with Nano-ITIES Pipet Electrode
T2 - A New Mechanism, Water/DCE-Octanoic Acid Interface
AU - Iwai, Nicholas Toshio
AU - Kramaric, Michelle
AU - Crabbe, Daniel
AU - Wei, Yuanyuan
AU - Chen, Ran
AU - Shen, Mei
N1 - Funding Information:
*Fax: +1 (217) 265-6290. E-mail: mshen233@illinois.edu. ORCID Mei Shen: 0000-0002-6033-8308 Author Contributions All authors have given approval to the final version of the manuscript. Funding This research was supported by the National Institute Neurological Disorder and Stroke of National Institutes of Health under Award Number R21NS085665. Notes The authors declare no competing financial interest.
Funding Information:
This research was supported by the National Institute Neurological Disorder and Stroke of National Institutes of Health under Award Number R21NS085665
Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/3/6
Y1 - 2018/3/6
N2 - Interface between two immiscible electrolyte solutions (ITIES) supported on the orifice of a pipet have become a powerful platform to detect a broad range of analytes. We present here the detection of γ-aminobutyric acid (GABA) with the nanoITIES pipet electrodes for the first time. GABA has a net charge of zero in an aqueous solution at pH ≈ 7, and it has not previously been detected at ITIES. In this work, we demonstrated GABA detection at ITIES in an aqueous solution at pH ≈ 7, where we introduced a novel detection strategy based on "pH modulation from the oil phase". To the best of our knowledge, this is the first report of such. Current increases linearly with increasing concentrations of GABA, ranging from 0.25 mM to 1.0 mM. The measured half-wave transfer potential of GABA is -0.401 ± 0.010 V (n = 22) vs E1/2,TBA. The measured diffusion coefficient for GABA detection at nanoITIES pipet electrode is 6.09 (±0.58) × 10-10 m2/s (n = 5). Experimental results indicate that protons generated from octanoic acid dissociation in the oil phase do not come out from the oil phase into the aqueous phase; neither were protons produced in the aqueous phase. NanoITIES pipet electrodes with radii of 320-340 nm were used in the current study. This new strategy and knowledge presented here lays the groundwork for the future development of ITIES pipet electrodes, especially for the detection of electrochemically nonredox active analytes.
AB - Interface between two immiscible electrolyte solutions (ITIES) supported on the orifice of a pipet have become a powerful platform to detect a broad range of analytes. We present here the detection of γ-aminobutyric acid (GABA) with the nanoITIES pipet electrodes for the first time. GABA has a net charge of zero in an aqueous solution at pH ≈ 7, and it has not previously been detected at ITIES. In this work, we demonstrated GABA detection at ITIES in an aqueous solution at pH ≈ 7, where we introduced a novel detection strategy based on "pH modulation from the oil phase". To the best of our knowledge, this is the first report of such. Current increases linearly with increasing concentrations of GABA, ranging from 0.25 mM to 1.0 mM. The measured half-wave transfer potential of GABA is -0.401 ± 0.010 V (n = 22) vs E1/2,TBA. The measured diffusion coefficient for GABA detection at nanoITIES pipet electrode is 6.09 (±0.58) × 10-10 m2/s (n = 5). Experimental results indicate that protons generated from octanoic acid dissociation in the oil phase do not come out from the oil phase into the aqueous phase; neither were protons produced in the aqueous phase. NanoITIES pipet electrodes with radii of 320-340 nm were used in the current study. This new strategy and knowledge presented here lays the groundwork for the future development of ITIES pipet electrodes, especially for the detection of electrochemically nonredox active analytes.
UR - http://www.scopus.com/inward/record.url?scp=85043235276&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85043235276&partnerID=8YFLogxK
U2 - 10.1021/acs.analchem.7b03099
DO - 10.1021/acs.analchem.7b03099
M3 - Article
C2 - 29388419
AN - SCOPUS:85043235276
SN - 0003-2700
VL - 90
SP - 3067
EP - 3072
JO - Analytical Chemistry
JF - Analytical Chemistry
IS - 5
ER -