A chronoamperometric method to estimate changes in the membrane composition of ion-selective membranes
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 time) of valinomycin-based, potassium-selective membranes loaded with potassium tetrakis(4-chlorophenyl)borate are correlated with the mobile-site and free ionophore concentration in the membrane. Limiting cases for strong and negligible ion pair formation are distinguished. Replicate measurements indicate a relative standard deviation in the calculated values less than 10%. The practical applicability of the method was tested with membranes incorporated into conventional ion-selective electrode bodies or cast onto microfabricated planar sensor structures.
Pendley, B., Gyurcsányi, R., Buck, R., & Lindner, E. (2001). A chronoamperometric method to estimate changes in the membrane composition of ion-selective membranes. Analytical Chemistry, 73 (19), 4599-4606. https://doi.org/10.1021/ac010007e