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Boise State Transuranics Sensor Project
Background
This highly selective sensor for actinides in water is based on a
specially prepared semiconducting organic polymer having selective
bonding sites for UO2+2 (uranyl ion) and other actinyl ions. The uranyl
ion is the most common and most stable form of uranium in water. This
binding site is chosen because it will preconcentrate uranyl
selectively, prior to detection. The advantage of this is that other
interfering ions will not be preconcentrated, and therefore the device
will be relatively insensitive to interferences.
Operation
The sensor is based on well-established principles of molecular
recognition, electroanalysis, and microelectronic device fabrication. A
super chelator for UO2+2, calix[n]arene (n=5,6), has been identified in
the literature, capable of distinguishing UO2+2 with a selectivity on
the order of 10E18 in the presence of other metal ions. The super
chelator (C6A), when attached to a conductive copolymeric film, is
incorporated into a microcircuit device. When the device contacts an
aqueous sample containing the UO2+2 ion, it pre-concentrates the ion in
the polymer film, causing alteration of several of its electrical
properties. These changes can be exploited for detection of the ion.
Microcircuit components can be included that permit operation in more
dynamic electroanalytical modes such as cyclic or squarewave voltammetry.
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