Electrochemical Impedance Study of Li - μ ISE Based on PPy [ LiClO 4 ] as a Solid Contact

The development of ion-selective microelectrodes for monitoring lithium ions in blood or serum is very important in the field of clinical chemistry. For this interest, all-solid-state microsensors based on impedance measurement for the detection of Li+ has been developed. The selective PVC membrane composition used was obtained by dissolving 1.2 % (w/w) Lithium ionophore III, 66 % (w/w) o-nitrophenyloctyl ether, 0.4 % of (potassium tetrakis(4-chlorophenyl)borate and 32.4% (w/w) polyvinylchloride (PVC) in tetrahydrofuran (THF). Then, the selective membrane was deposited onto gold microelectrodes containing a conducting polymer (polypyrrole doped with Lithium perchlorate) as solid contact layer. The developed Li+-ISE provides excellent performance towards the determination of lithium with a low detection limit of 6×10-8 M and a wide linear range from 1x10-7 M to 1x10-1 M covering the clinically interesting of Lithium range (0.5×10-3 to 1.5×10-3 M); The selectivity properties have been examined obtaining good results. Copyright © 2014 IFSA Publishing, S. L.