New membrane for copper-selective electrode incorporating a new thiophosphoril-containing macrocycle as neutral carrier

The new macrocycles 4-phenyl-11-(1-oxodecyl)-1,7-dithia-11-aza-4-phosphacyclotetradecane (III) and 4-phenyl-4-sulfide-11-(1-oxodecyl)-1,7-dithia-11-aza-4-phosphacyclotetradecane (IV) have been synthesised and characterised. Through their use as ionophore in an all-solid state poly(vinylchloride) matrix membrane electrode, the ability of IV as cation receptor has been studied. The electrode exhibits a Nernstian response towards copper (II) ions with a cationic slope of 30.7 ± 1.7 mV per decade, over the concentration range 3.0 × 10− 6 to 1.0 × 10− 2 M and the potential response remains almost unchanged over the pH range 3.9–6.4. The electrode can be used for at least seven months without a considerable alteration in its potential.