Development a Flow Rinsing System for Improving the Detection Limit of Solvent Polymeric Membrane Ion-selective Electrodes

作者：Tohda Koji^*; Hosokawa Naoki; Thi Hong Nhung Dao; Kanno Akira

来源：Bunseki Kagaku, 2018, 67(5): 239-247.

DOI：10.2116/bunsekikagaku.67.239

• solvent polymeric membrane
• ion-selective electrode
• lower detection limit
• chelating solution
• flow-through system
• trace level analysis
• ion flux model
• transient potential response

In order to improve the lower detection limit of solvent polymeric membrane ion-selective electrodes (ISEs), a flow-through system with an ISE based on a highly selective and lipophilic Pb2+ ionophore, ETH5435, was constructed. This flow-through system has a function to remove most Pb2+ remaining at the phase boundary of the ISE membrane with feeding EDTA chelating solutions just before sample feeding. By feeding a trace level of HP solutions into the flow-through system, transient potentiometeric responses for Pb2+ were observed in the concentration range of 1 X 10(-9) mol L-1 to 1 X 10(-6) mol L-1 which was lower than the detection limit of conventional Pb2+-ISEs. The observed transient potential responses were analyzed based on an ion-flux model across the membrane/sample solution interface. As a result, it was found that plotting the gradient of the transient potential response immediately after sample feeding provides a calibration curve with good linearity from a sub-ppb to ppb Pb2+ concentration range.

• 出版日期2018-5