Organic tin compounds combined with anionic additives-an ionophore system leading to a phosphate ion-selective electrode?
The potentiometric response characteristics of electrodes based on organic trialkyl/aryl-tin compounds combined with various amounts of anionic additive (NaTFPB) were investigated in 0.1M bis-Tris-H(2)SO(4) buffer solution at pH 7.0. The best result for phosphate sensing was obtained for the electrode membrane containing tributyltin chloride and 25mol% NaTFPB, where the electrode exhibits high selectivity towards phosphate anions with a slope of -60mV per decade. It was demonstrated that the interference from more lipophilic anions is drastically suppressed (log K (ij)(pot ), i=H(2)PO(4)(-): salicylate, 0.5; SCN(-), -0.8; ClO(4)(-), -2.3) under this optimized measurement conditions.
Sasaki
S
S
Department of Applied Chemistry, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
Ozawa
S
S
Citterio
D
D
Yamada
K
K
Suzuki
K
K