Bd. Pendley et al., A chronoamperometric method to estimate changes in the membrane composition of ion-selective membranes, ANALYT CHEM, 73(19), 2001, pp. 4599-4606
A new chronoamperometric method is used to estimate changes in the membrane
composition of mobile-site, ionophore-based membranes. The characteristic
features of the chronoamperometric curves (initial current, slope, break ti
me) of valinomycin-based, potassium-selective membranes loaded with potassi
um tetrakis(4-chlorophenyl)borate are correlated with the mobile-site and f
ree ionophore concentration in the membrane. Limiting cases for strong and
negligible ion pair formation are distinguished. Replicate measurements ind
icate a relative standard deviation in the calculated values less than 10%.
The practical applicability of the method was tested with membranes incorp
orated into conventional ion-selective electrode bodies or cast onto microf
abricated planar sensor structures.