AMPEROMETRIC SENSOR FOR THE FLOW-INJECTION DETERMINATION OF IRIDIUM(IV) IONS

The electrochemical behavior of iridium(IV) chloride complexes was stu died by cyclic and hydrodynamic voltammetry on carbon composite electr odes manufactured on the basis of a mixture of carbon powder and a hyd rophobic silicone support covalently bonded with molecules of thiacrow n compounds and their analogues. An amperometric sensor was proposed o n the basis of an electrode modified by 1,4-dioxa-7,10-dithiacyclodode cane, and its potential use for the flow-injection determination of ir idium(IV) ions in chloride solutions was demonstrated. The calibration graph was Linear in the concentration range 0.05-0.50 mM Ir; the dete ction limit was 10 mu M. For the determination of iridium in model sol utions containing Fe(II), Hg(II), Cu(II), Pd(IV), Pt(II), Rh(III), and (Ru(IV) ions, the relative standard deviation did not exceed 5% (n = 6). The throughput was 50-180 h(-1) for a sample volume of 400 mu L.