Improved ion-selective detection method using nanopipette with poly(vinyl chloride)-based membrane.
Ion-selective electrodes (ISEs) are widely used to detect targeted ions in solution selectively. Application of an ISE to a small area detection system with a nanopipette requires a special measurement method in order to avoid the enhanced background signal problem caused by a cation-rich layer near the charged inner surface of the nanopipette and the selectivity change problem due to relatively fast saturation of the ISE inside the nanopipette. We developed a novel ion-selective detection system using a nanopipette that measures an alternating current (AC) signal mediated by saturated ionophores in a poly(vinyl chloride) (PVC) membrane located at the conical shank of the nanopipette to solve the above problems. Small but reliable K(+) and Na(+) ionic current passing through a PVC membrane containing saturated bis(benzo-15-crown-5) and bis(12-crown-4) ionophore, respectively, could be selectively detected using the AC signal measurement system equipped with a lock-in amplifier.
Division of Quantum Phases and Devices, Department of Physics, Konkuk University , Seoul 143-701, Republic of Korea.
Eun Ji
EJ
Kang
Tomohide
T
Takami
Xiao Long
XL
Deng
Jong Wan
JW
Son
Tomoji
T
Kawai
Bae Ho
BH
Park
D002414:Cations, Monovalent; D043844:Crown Ethers / Q000737:chemistry; D007476:Ionophores / Q000737:chemistry*; D008567:Membranes, Artificial; D008839:Microelectrodes; D011143:Polyvinyl Chloride; D011188:Potassium / Q000032:analysis*; D011199:Potentiometry / Q000295:instrumentation / Q000379:methods*; D012964:Sodium / Q000032:analysis*; D012996:Solutions; D014867:Water / Q000737:chemistry
D002414:Cations, Monovalent; D043844:Crown Ethers; D007476:Ionophores; D008567:Membranes, Artificial; D012996:Solutions; D014867:Water; C042148:15-crown-5; D011143:Polyvinyl Chloride; D012964:Sodium; C557123:12-crown-4; D011188:Potassium