Improving the detection limit of anion-selective electrodes: an iodide-selective membrane with a nanomolar detection limit.
The lower detection limit and the selectivity behavior of anion-selective electrodes (ISEs) are improved by using optimized inner solutions and membrane compositions. With a membrane based on the recently described ionophore [9]mercuracarborand-3, a detection limit of 2 x 10(-9) M has been achieved for iodide. Nevertheless, the improvements are less pronounced than in the case of cation ISEs. This is mainly due to the fact that so far no anion ISE is known with the extremely high selectivities of cation ISEs. If the membrane does not contain an ionophore, leaching of the ion exchanger from the membrane into the sample is also a relevant limiting factor except for ion exchangers of very high lipophilicity.
Laboratorium für Organische Chemie, ETH Hönggerberg, CH-8093 Zürich, Switzerland.
Adam
A
Malon
Aleksandar
A
Radu
Wei
W
Qin
Yu
Y
Qin
Alan
A
Ceresa
Magdalena
M
Maj-Zurawska
Eric
E
Bakker
Emö
E
Pretsch
D000838:Anions / Q000737:chemistry*; D004566:Electrodes; D007454:Iodides / Q000737:chemistry*; D007476:Ionophores / Q000032:analysis; D008567:Membranes, Artificial; D008832:Microchemistry / Q000379:methods*; D010472:Perchlorates / Q000032:analysis; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D012680:Sensitivity and Specificity; D012965:Sodium Chloride; D017670:Sodium Compounds / Q000032:analysis; D012974:Sodium Iodide
D000838:Anions; D007454:Iodides; D007476:Ionophores; D008567:Membranes, Artificial; D010472:Perchlorates; D000644:Quaternary Ammonium Compounds; D017670:Sodium Compounds; D012965:Sodium Chloride; C009543:tridodecylmethylammonium; C031068:sodium perchlorate; D012974:Sodium Iodide