“…Different types of chemical sensors have been prepared from conducting polymers by using functional dopants, like naphthalenesulfonates [62 ± 64], indigo carmine [65], bathophenantroline disulfonate [66,67], alizarin red S [68], bathocuproine sulfonate [69], sulfosalicylic acid [69 ± 71], hexacyanoferrate [72], tiron [70,71], eriochrome black T [70,71], kalces [70,71], arsenazo-I [71], calcon [71], p-tetrasulfonato-calix [4]arene [73,74], p-tetra- sulfonato-calix [6]arene [73,75], tetraphenylporphine tetrasulfonic acid [76], dodecylbenzene sulfonate [77], calmagite [78], calcion [79], 3-(2-pyridyl)-5,6-diphenyl-4,4'-disulfonate-1,2,4-triazine [80], di(2-ethylhexyl)phosphate [81], bis[4-(1,1,3,3-tetramethylbutyl)phenyl]phosphate [82]. Also neutral ionophores, like 18-crown-6 [83], valinomycin [84], ETH 1001 [85], as well as the positively charged tridodecylmethylammonium ion [86] have been used as ionrecognition sites in conducting polymer membranes. The majority of these conducting polymers with (non-covalently) immobilized ion-recognition sites were studied as potentiometric ion sensors (ion-selective electrodes, ISEs) [62 ± 65, 70 ± 72, 76 ± 79, 81, 82, 84 ± 86].…”