Vol. 1, No 2, 1995 pp. 171 - 178
UDC
543.422.5
DETERMINATION OF NANOGRAMME Mn(II) AMOUNTS BY CATALYTIC OXIDATION OF CARMINE ACID WITH H2O2 IN THE PRESENCE OF ACTIVATORS
T.G. Pecev, R.P. Igov, S.M. Rančić
Faculty of Science, Department of Chemistry, Ćirila i Metodija 2, 18000 Niš
Abstract. In one of previous works [1], the new catalytic reaction was suggested and the new kinetic method was prepared for ultra-micro amounts of Mn(II) ions on the carmine acid oxidation by hydrogene-peroxide in ammon-buffer. Under the optimal initial conditions sensitivity of 1∙10-8 g/cm3 Mn(II) in the solution was reached.
In this labour, effect of electron-acceptor ligands: 1,10-phenantroline and 2,2'- dypyridile. was studied. Their effect on the indicatory reaction rate and the sensitivity of Mn(II) determination, was investigated. On the basis of the indicatory reaction kinetic examinations, the mechanism of activatory effect of phenantroline and dypyridile, was suggested.
In the presence of phenantroline, sensitivity of 5∙10-10 g/cm3 was reached, while in the presence of dypyridile, it was 1∙10-10 g/cm3 Mn(II). That means that indicatory reaction sensitivity in the presence of activators, was about 100 times greater than without them. Kinetic results were worked out by tangent method [2].
ODREĐIVANJE NANOGRAMSKIH KOLIČINA Mn(II) KATALITIČKOM OKSIDACIJOM KARMINSKE KISELINE VODONIK-PEROKSIDOM U PRISUSTVU AKTIVATORA
U jednom od prethodnih radova, [1], predložena je nova katalitička reakcija i razrađena kinetička metoda za određivanje ultra-mikro količina Mn(II), na bazi njegovog katalitičkog dejstva na reakciju oksidacije karminske kiseline vodonik-peroksidom u amonijačnom puferu. Pri određenim optimalnim uslovima odvijanja reakcije postignuta je osetljivost od 1∙10-8 g/cm3 Mn(II) u rastvoru.
U ovom radu, proučavan je uticaj liganada sa elektron-akceptorskim osobinama, kao što su: 1,10-fenantrolin i 2,2'-dipiridil, na brzinu pomenute indikatorske reakcije u cilju razrade što osetljivije kinetičke metode za određivanje katalizatora - mangana. Na osnovu ispitivanja kinetike katalizovane indikatorske reakcije, predložen je mehanizam aktivatorskog dejstva fenantrolina i dipiridila.
U prisustvu fenantrolina postignuta je osetljivost od 5∙10-10 g/cm3, a u prisustvu dipiridila - 1∙10-10 g/cm3, odnosno, osetljivost je povećana za dva reda veličine u odnosu na postignutu osetljivost bez aktivatora. Kinetički podaci su obrađeni tangensnom metodom, [2].
