MicroITIES detection of nitrate by facilitated ion transfer

A microITIES array, created by laser photoablation of a 12-mum polyester fi lm, was used to investigate electroassisted anion transfer between two immi scible electrolyte solutions. Besides measuring directly the transfer of ni trate to the organic phase, the enhancement of transfer of the cation (K+) by facilitated anion (counterion) transfer was measured as well. In the pre sence of a triamide derived from tris(2-aminoethyl)amine (tren), which is k nown to function as a host for nitrate, the current responses for both nitr ate and potassium transfer were monitored. The linear relationships between the current responses and nitrate concentration formed the basis of an ani on sensor with a dynamic range from 0.1 to 5 mM. A dual facilitated transfe r mechanism is proposed to explain the enhancement phenomenon.