Logic gates from ion-selective bulk optodes

Abstract

Optode membranes incorporating tetramethoxyethylester calix[4]arene or valinomycin for sodium ion or potassium ion recognition, respectively, and different types of chromoionophores in a plasticized poly(vinyl chloride) (PVC) matrix were prepared to operate as chemical logic gates. A competitive ion exchange equilibrium, which was the response mechanism, could relate to a logic system under the action of two chemical inputs (H⁺ and Na⁺/K⁺). The response change, an optical character of optode membranes, was the output signal. The absorbance behaviors of sodium- and potassium-selective bulk optodes at different protonation and coordination environments were studied extensively. Typical bulk optode systems, i.e.sodium and potassium bulk optodes, were found to function as INH A, INH B, NINH A, NINH B, AND, NAND, OR and NOR gates. NOR and OR gates were also achieved from the modified mixed-ionophore optode systems (tetramethoxyethylester calix[4]arene and valinomycin) with Na⁺ and K⁺ as inputs. Mismatched ionophore-analyte ion optodes (tetramethoxyethylester calix[4]arene-K⁺) also produced 8 gates similar to the matched ionophore bulk optodes, and could possibly be used to determine the predominant ion in mixed-ion solutions.