Vol. 1, No 1, 1994 pp. 64 - 73
UDC 543.422.5

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KINETIC DETERMINATION OF ULTRAMICRO AMOUNTS OF Fe(III) IN CLEAR JUICE
G.Ž. Miletić and S.S. Mitić
Department of Chemistry, Faculty of Philosophy, University of Niš, 18000 Niš, Yugoslavia

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Abstract. A new kinetic method is suggested for determining traces of iron(III) on the basis of their inhibiting effect on the Co(II) catalysis of oxidation of purpurine with hydrogen peroxide. The sensivity of the method is 20 ng/cm3. Kinetic equations were proposed for the investigated process. The effects of certain foreign ions upon the reaction rate were determined for the assessment of the selectivity of the method. The method was applied to determine Fe(III) in fruit juice.

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KINETIČKO ODREĐIVANJE ULTRAMIKRO KOLIČINA Fe(III) U BISTRIM SOKOVIMA Predložena je nova kinetička metoda za određivanje tragova Fe(III) na bazi njihovog inhibitorskog dejstva na reakciju oksidacije purpurina vodonikperoksidom koja je katalizovana sa Co(II). Osetljivost metoda je 20 ng/cm3. Relativna greška se kreće od 0,8 do 4,3% za interval koncentracije od 320 do 20 ng/cm3. Predložene su kinetičke jednačine za proučavani proces. Radi ocene selektivnosti metode ispitan je uticaj izvesnog broja stranih jona na brzinu reakcije. Metoda je primenjena za određivanje tragova Fe(III) u bistrim sokovima.