Properties of electrolyte-filled glass microelectrodes : an experimental study
(1997) In Journal of Neuroscience Methods 78(1-2). p.15-28- Abstract
The electrochemical and electrical properties of geometrically defined electrolyte-filled microelectrodes were studied at various transelectrode current passages, using radiotracer (38Cl and 42K) and electrical techniques. Geometrically, the electrodes were defined by their tip properties that, for standard (single-barrelled, 3.0 M KCl-filled, approximately 10 M[ohm]) electrodes implied a tip opening radius of 0.135 microm and a tip taper of 0.0215 microm/microm in the most distal (0-150 microm), and of 0.0105 microm/microm in the next most distal (150-1000 microm) tip regions. From the radiotracer studies it followed that (a) in the absence of transelectrode current passage, K+ and Cl- are leaking from the electrode tip in amounts... (More)
The electrochemical and electrical properties of geometrically defined electrolyte-filled microelectrodes were studied at various transelectrode current passages, using radiotracer (38Cl and 42K) and electrical techniques. Geometrically, the electrodes were defined by their tip properties that, for standard (single-barrelled, 3.0 M KCl-filled, approximately 10 M[ohm]) electrodes implied a tip opening radius of 0.135 microm and a tip taper of 0.0215 microm/microm in the most distal (0-150 microm), and of 0.0105 microm/microm in the next most distal (150-1000 microm) tip regions. From the radiotracer studies it followed that (a) in the absence of transelectrode current passage, K+ and Cl- are leaking from the electrode tip in amounts corresponding to currents of +/- 3.8 nA, and (b) in the presence of transelectrode current passage, the flow of K+ and Cl- through the electrode tip changes with the transelectrode current in a statistically linear fashion so that K+ carries about 80% and Cl- about 20% of any electrode-injected current. From the electrical measurements it appeared that the standard electrodes are characterized by (a) a tip potential of -2.6 mV, and (b) a resistance that changes from an instantaneous, non-rectifying type to a steady state, outwardly rectifying type, within tenths of a second of constant current flow. The outward current rectification was seen to be reduced by raising [KCl] in the immersing solution, or by lowering it in the filling solution. Together, the observed electrode properties are consistent with the electrode electrolyte's solute and solvent turnover being governed by electro-osmotic as well as by electrodiffusion laws.
(Less)
- author
- Fåhraeus, C LU ; Borglid, K and Grampp, W LU
- organization
- publishing date
- 1997-12-30
- type
- Contribution to journal
- publication status
- published
- keywords
- Chlorides/analysis, Electrochemistry/instrumentation, Electrolytes, Equipment Design, Microelectrodes, Potassium/analysis, Potassium Radioisotopes, Radiopharmaceuticals/analysis, Scintillation Counting/methods, Sensitivity and Specificity
- in
- Journal of Neuroscience Methods
- volume
- 78
- issue
- 1-2
- pages
- 14 pages
- publisher
- Elsevier
- external identifiers
-
- pmid:9496998
- scopus:0345055337
- ISSN
- 0165-0270
- DOI
- 10.1016/S0165-0270(97)00128-3
- language
- English
- LU publication?
- yes
- id
- e0ac3a8a-624d-4186-bea0-7574e81aecb2
- date added to LUP
- 2018-12-18 15:57:34
- date last changed
- 2024-01-15 10:19:21
@article{e0ac3a8a-624d-4186-bea0-7574e81aecb2,
abstract = {{<p>The electrochemical and electrical properties of geometrically defined electrolyte-filled microelectrodes were studied at various transelectrode current passages, using radiotracer (38Cl and 42K) and electrical techniques. Geometrically, the electrodes were defined by their tip properties that, for standard (single-barrelled, 3.0 M KCl-filled, approximately 10 M[ohm]) electrodes implied a tip opening radius of 0.135 microm and a tip taper of 0.0215 microm/microm in the most distal (0-150 microm), and of 0.0105 microm/microm in the next most distal (150-1000 microm) tip regions. From the radiotracer studies it followed that (a) in the absence of transelectrode current passage, K+ and Cl- are leaking from the electrode tip in amounts corresponding to currents of +/- 3.8 nA, and (b) in the presence of transelectrode current passage, the flow of K+ and Cl- through the electrode tip changes with the transelectrode current in a statistically linear fashion so that K+ carries about 80% and Cl- about 20% of any electrode-injected current. From the electrical measurements it appeared that the standard electrodes are characterized by (a) a tip potential of -2.6 mV, and (b) a resistance that changes from an instantaneous, non-rectifying type to a steady state, outwardly rectifying type, within tenths of a second of constant current flow. The outward current rectification was seen to be reduced by raising [KCl] in the immersing solution, or by lowering it in the filling solution. Together, the observed electrode properties are consistent with the electrode electrolyte's solute and solvent turnover being governed by electro-osmotic as well as by electrodiffusion laws.</p>}},
author = {{Fåhraeus, C and Borglid, K and Grampp, W}},
issn = {{0165-0270}},
keywords = {{Chlorides/analysis; Electrochemistry/instrumentation; Electrolytes; Equipment Design; Microelectrodes; Potassium/analysis; Potassium Radioisotopes; Radiopharmaceuticals/analysis; Scintillation Counting/methods; Sensitivity and Specificity}},
language = {{eng}},
month = {{12}},
number = {{1-2}},
pages = {{15--28}},
publisher = {{Elsevier}},
series = {{Journal of Neuroscience Methods}},
title = {{Properties of electrolyte-filled glass microelectrodes : an experimental study}},
url = {{http://dx.doi.org/10.1016/S0165-0270(97)00128-3}},
doi = {{10.1016/S0165-0270(97)00128-3}},
volume = {{78}},
year = {{1997}},
}