title: A chronoamperometric method to estimate changes in the membrane composition of ion-selective membranes.
abstract: 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.
authors.affiliation: Department of Chemistry, Rhodes College, Memphis, Tennessee 38112, USA.
authors.forename: B D
authors.initials: BD
authors.lastname: Pendley
authors.forename: R E
authors.initials: RE
authors.lastname: Gyurcsányi
authors.forename: R P
authors.initials: RP
authors.lastname: Buck
authors.forename: E
authors.initials: E
authors.lastname: Lindner
mesh_terms: D004563:Electrochemistry / Q000379:methods; D007476:Ionophores / Q000737:chemistry*; D008567:Membranes, Artificial; D011188:Potassium / Q000737:chemistry*; D013775:Tetraphenylborate / Q000031:analogs & derivatives* / Q000737:chemistry; D014634:Valinomycin / Q000737:chemistry
chemical_list: D007476:Ionophores; D008567:Membranes, Artificial; C030385:tetrakis(4-chlorophenyl)borate; D014634:Valinomycin; D013775:Tetraphenylborate; D011188:Potassium