KINETIC OF COPPER(III) (II) TETRAGLYCINE REACTIONS WITH SULFITE - ANALYTICAL POTENTIALITIES/

The oxidation of Cu(II)/tetraglycine complex In berate buffer (pH=9.2) in aqueous medium, by dissolved oxygen is strongly accelerated by S(I V). The reaction is adequate for S(IV) determination as the concentrat ion of [Cu(H(-3)G(4))](-) formed is proportional to SO32- concentratio n. The [Cu(H(-3)G(4))](-) presents a maximum absorbance at 365 nm (eps ilon = 7400 mol(-1).L.cm(-1)) and it was followed spectrophotometrical ly by flow injection analysis procedure. The detection limit was 7x10( -6) mol.L-1 and the linear regression showed a standard deviation of 0 .02% (n=5). Kinetics studies showed the catalytic effect of some trans ition metal ions, which can be present in environmental samples, in th e oxidation of S(IV). The pseudo-first-order rate constants were deter mined in the presence of formaldehyde.