Novel potentiometric and optical silver ion-selective sensors with subnanomolar detection limits.
Ten Ag+-selective ionophores have been characterized in terms of their potentiometric selectivities and complex formation constants in solvent polymeric membranes. The compounds with pi-coordination show much weaker interactions than those with thioether or thiocarbamate groups as the coordinating sites. Long-term studies with the best ionophores show that the lower detection limit of the best Ag+ sensors can be maintained in the subnanomolar range for at least 1 month. The best ionophores have also been characterized in fluorescent microspheres. The so far best lower detection limits of 3 x 10(-11) M (potentiometrically) and 2 x 10(-11) M Ag+ (optically) are found with bridged thiacalixarenes.
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Laboratorium für Organische Chemie, ETH Zürich, CH-8093 Zürich, Switzerland.
Malon
Adam
A
Vigassy
Tamás
T
Csokai
Viktor
V
Grün
Alajos
A
Wygladacz
Katarzyna
K
Ye
Nan
N
Xu
Chao
C
Chebny
Vincent J
VJ
Bitter
István
I
Rathore
Rajendra
R
Bakker
Eric
E
Pretsch
Ernö
E