Herein, the construction and performance characteristic of a polymeric membrane electrode based on ion-pair formation of salmon sperm ds-DNA-amiloride for quantification of amiloride is described. Salmon sperm ds-DNA-amiloride layer can be prepared easily as a coating layer on a Pt-wire electrode. This electrode has a good potentiometric response to amiloride. The influences of the membrane compositions on the potentiometric response of the electrode have been found to substantially improve the performance characteristics. The best performance was obtained with the electrode having a membrane composition (m/m) of ds-DNA-amiloride as an ion pair (6.4%), polyvinyl chloride (PVC) matrix (62.9%), and 2-nitrophenyl octylether (NPOE) as an ion excluder (30.7%). The proposed electrode exhibits Nernstian response in the concentration range of 1.6 10-6 to 1.0 × 10-2 mol L-1 amiloride with a detection limit of 1.5 × 10-6 mol L-1 amiloride, performs satisfactorily with a fast response time of 5 s. Selectivity coefficients for amiloride relative to a numbers of potential interfering substances were investigated. The sensor was highly selective for amiloride over a large number of compounds. The analytical usefulness of the proposed electrode has been evaluated by its application in the determination of amiloride in real samples.
amiloride determination; ds-DNA modified electrode; potentiometry
