Evaluation of a new wall-jet flow-through cell for commercial ion-selective electrodes in flow injection potentiometry

An improved wall-jet configuration type flow-through cell has been developed for use with commercial ion-selective electrodes (ISEs) and has been evaluated in the how injection potentiometric (FIP) mode. The flow-through cell was designed to accommodate commercial ISEs that employ a range of sensing surfaces, including gas-sensing, liquid polymer membrane and solid-state based ISEs. Commercial ISEs employed for the evaluation of the flow-through cell were ammonia, calcium and iodide ion-selective electrodes. The observed electrode slopes were -58.8 +/- 0.9, 25.2 +/- 0.5 and -58.3 +/- 0.9 mV change/activity decade, respectively, over a wide log-linear range using a 100 mu L sample volume in the FIP mode. Sample throughput rates as fast as 240 injections/h and analytically useful peak height responses can be achieved using injected sample volumes a slow as 25 mu L with all three types of ISEs.