PMID- 23794083
OWN - NLM
STAT- MEDLINE
DCOM- 20140710
LR  - 20211021
IS  - 1432-1017 (Electronic)
IS  - 0175-7571 (Linking)
VI  - 42
IP  - 8
DP  - 2013 Aug
TI  - An optimised 3 M KCl salt-bridge technique used to measure and validate 
      theoretical liquid junction potential values in patch-clamping and 
      electrophysiology.
PG  - 631-46
LID - 10.1007/s00249-013-0911-3 [doi]
AB  - Accurate potential measurements in electrophysiological experiments require 
      correction for liquid junction potentials (LJPs), and, in patch-clamping 
      especially, these can often be ~5-10 mV or more. They can be either calculated, 
      if ion mobilities are known, or measured directly. We describe an optimised 
      system to directly measure LJPs with a patch-clamp amplifier, using as a 
      reference electrode, a freshly-cut 3 M KCl-agar salt-bridge (in polyethylene 
      tubing) with its tip cut off by at least 5 mm during solution changes to 
      eliminate its solution-history-dependent effects. We quantify such 
      history-dependent effects and complement this with a de-novo theoretical analysis 
      of salt diffusion to and from the salt-bridge. Our analysis and experimental 
      results validate the optimised methodology for measuring LJPs, and the use of the 
      Henderson equation for accurately calculating them. The use of this equation is 
      also assessed and generally validated in the light of rigorous 
      Nernst-Planck-Poisson and other numerical simulations and analytical studies of 
      LJPs over recent decades. Digitizing, recording and amplifying the measured 
      potentials increases their accuracy. The measured potentials still need 
      correction for small, well-defined calculable, shifts in LJPs at the 3 M KCl-agar 
      reference. Using this technique, we have measured changes in LJPs for diluted 
      solutions of NaCl, LiCl, KCl, CsCl and NaF, obtaining excellent agreement within 
      +/-0.1 mV of predicted values, calculated using ion activities. Our de novo LJP 
      measurements of biionic combinations of the above undiluted salts, and NaI and 
      NaF (with halide anions I(-) and F(-)), generally also gave excellent agreement with 
      predicted values.
FAU - Barry, Peter H
AU  - Barry PH
AD  - Department of Physiology, School of Medical Sciences, University of New South 
      Wales-UNSW, Sydney, NSW 2052, Australia. P.Barry@unsw.edu.au
FAU - Lewis, Trevor M
AU  - Lewis TM
FAU - Moorhouse, Andrew J
AU  - Moorhouse AJ
LA  - eng
PT  - Journal Article
DEP - 20130621
PL  - Germany
TA  - Eur Biophys J
JT  - European biophysics journal : EBJ
JID - 8409413
RN  - 0 (Ionic Liquids)
RN  - 660YQ98I10 (Potassium Chloride)
RN  - 9002-18-0 (Agar)
SB  - IM
MH  - Agar/chemistry
MH  - Diffusion
MH  - Electrodes
MH  - *Electrophysiology
MH  - Ionic Liquids/chemistry
MH  - *Models, Theoretical
MH  - Patch-Clamp Techniques
MH  - *Physical Phenomena
MH  - Potassium Chloride/*chemistry
MH  - Reproducibility of Results
EDAT- 2013/06/25 06:00
MHDA- 2014/07/11 06:00
CRDT- 2013/06/25 06:00
PHST- 2012/11/12 00:00 [received]
PHST- 2013/05/09 00:00 [accepted]
PHST- 2013/06/25 06:00 [entrez]
PHST- 2013/06/25 06:00 [pubmed]
PHST- 2014/07/11 06:00 [medline]
AID - 10.1007/s00249-013-0911-3 [doi]
PST - ppublish
SO  - Eur Biophys J. 2013 Aug;42(8):631-46. doi: 10.1007/s00249-013-0911-3. Epub 2013 
      Jun 21.