Novel sensing device based on potentiometric measurement for the detection of lithium

S. Merzouk, N. Zine, M. Tahajanan, M. Agouzoul, J. Bausells, F. Teixidor, N. Jaffrezic-Renault, A. Errachid
Institut des Sciences Analytiques, FR

Keywords: Ion-selective electrode, conducting polymer, Potentiometry, lithium

Summary:

The therapy of manic depressive psychosis with lithium salts requires periodic measurements of the Li concentration in whole blood, plasma, urine or serum. The analysis is difficult because of the low lithium concentration compared to the high content of the natural cations (especially Na+). Lithium has a narrow therapeutic range (0.5-1.5 mM), and too low of a dosage leads to ineffectiveness and too high leads to severe toxicity. Accurate and rapid monitoring of the Li activity in blood for the patients in lithium therapy is critically important as the gap between its therapeutic and toxic levels are very close. In this work, we report a novel sensing device based on a potentiometric measurement for the detection of Li+, by combining [Co(C2B9H11)2]- and the Lithium ionophore III (ETH1810).The developed µISE provides excellent performance towards the determination of lithium with a high sensitivity of 52 ± 2 mV/decade, a low detection limit of 1x10-6 M and a wide linear range from 4.10-5 M to 1.10-1 M (Figure 3) covering the clinically interesting Li+ range . Furthermore, the developed µISE will be a promising chemical sensing device for the measurement of Lithium in pharmaceutical preparations of Lithium treatments .