Novel sensing device based on potentiometric measurement for Lithium detection

Abstract

The main objective of this work is the determination of lithium by Solid contact ion-selective microelectrodes (SC-uISE) based on silicon technology. A film of polypyrrole doped with cobaltabis(dicarbollide) anion [3,3'-Co(l,2-C2B9H11)2] was deposited on gold microelectrodes by electrochemical polymerization. The PPy[Co(C2B9H11)2] was subsequently coated with poly(vinyl chloride) matrix membrane containing Lithium ionophore III (ETH 1810). The developed potentiometric SC-μISE provides excellent performance towards the determination of lithium with a high sensitivity of 52 ± 2 mV/decade, a low detection limit of 1×10-6 M and a wide linear range from 4.10-5 to 1.10-1 M covering the clinically interesting Li+ range. The SC-μISE exhibits a good selectivities for lithium over other cathions: logKpotLi, Mg= -4.35, logKpotLi, K= -4.09, logK potLi, N114= -3.39, logKpotLi, Ca= -2.6 and logKpotLi, Na= -2.5. Furthermore, the developed SC-uISE will be a promising chemical sensing device for the measurement of Lithium in pharmaceutical preparations of Lithium treatments.