Kinetic of Copper(III)/(II) Tetraglycine Reactions with Sulfite. Analytical Potentialities |
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| Authors: | Deborah Yoshida Horacio D Moya Rodrigo L Bonifácio Nina Coichev |
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| Institution: | Institute de Química - USP , Caixa Postal 26077 - CEP 05599-970, S?o Paulo, SP, Brazil |
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| Abstract: | Abstract The oxidation of Cu(II)/tetraglycine complex in borate buffer (pH=9.2) in aqueous medium, by dissolved oxygen is strongly accelerated by S(IV). The reaction is adequate for S(IV) determination as the concentration of (Cu(H-3G4)]? formed is proportional to SO32- concentration. The Cu(H-3G4)]? presents a maximum absorbance at 365 nm (? = 7400 mol?1.L.cm?1) and it was followed spectrophotometrically by flow injection analysis procedure. The detection limit was 7×10?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 transition metal ions, “which can be present in environmental samples, in the oxidation of S(IV). The pseudo-first-order rate constants were determined in the presence of formaldehyde. |
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| Keywords: | Cu(II)/(III) tetraglycine sulfite formaldehyde flow injection analysis |
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