Measurement of the limiting equivalent conductivities and mobilities of the most prevalent ionic species of EGTA (EGTA2- and EGTA3-) for use in electrophysiological experiments

Abstract

In many experimental biological situations, chelating agents like EGTA (ethylene glycol-bis-(β-amino-ethyl ether) N,N,N',N'-tetra-acetic acid) are commonly used to control or suppress the concentration of divalent ions like Ca2+. The evaluation of liquid junction potentials in electrophysiological measurements, and particularly in patch-clamp situations, requires information about the ions within the solution. Where there is a significant concentration of EGTA present, it is necessary to know the values of the relative mobility of at least the most predominant ionic species of EGTA in order to complete these calculations. EGTA, with four negative charges with different pK(a)s, can therefore ..