PVC membranes based on silver(I)-thiourea complexes

Polymer membrane ion-selective electrodes have been prepared using the silver(I) complex of two novel thioureas (N-diethylamino-thiocarbonil-benzimido methyl-thioester, TBTE, and N-(N',N'-diethyl-thiocarbamoyl)-N "-phenyl-benzamidine, TCBA). Both electrodes were highly selective to iodide, with Nernstian response for this anion, and sub-Nerstian responses for thiocyanate and bromide. The detection limits were around 3 x 10(-9) M, the main differences in the electrode characteristics being the response times. Membranes prepared with the TBTE complex responded faster than TCBA. This behavior is related to the different structures of the ligands, A comparison of the response characteristics of both complexes is also discussed. (C)1999 Elsevier Science B.V. All rights reserved.