PULSE AMPEROMETRIC DETECTION OF LITHIUM IN ARTIFICIAL SERUM USING A FLOW-INJECTION SYSTEM WITH A LIQUID LIQUID-TYPE ION-SELECTIVE ELECTRODE/

A voltammetric ion-selective electrode based on the facilitated transf er of Li+ by dibenzyl-14-crown-4 at the o-nitrophenyl phenyl ether/wat er interface was applied to the amperometric detector in a FIA system for Li+ with a cation-exchange column. The current response was stably detected by pulse amperometry in which voltage pulses of short durati on (50 ms) were applied at the interval of 2 s. With this FIA system, 0.2-2.0 mM Li+ in aqueous solution could be determined even in the pre sence of 120-160 mM Na+, the detection limit being 0.15 mM. A test usi ng artificial serum demonstrated the practical applicability of this s ystem.