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Determination of free manganese(II) ions in decoctions and infusions of some medicinal plants by catalytic method

Mutaftchiev K. L.

Chemia Analityczna

2002

Vol. 47, No. 2

289-298

The catalytic effect of manganese(II) ions on the oxidation of l-butyl-3,3-dimethyl-2-[5-(l-butyl-3.3-dimethyl-3H-benzindolin-2-yliden)-l,3-pentadienyl]-3H-benzindoliumper-chlorate (DB1PP) with potassium periodate in the presence of 1.10-phenanthroline in weakly acidicmedia was studied. Thereaction was followed spectrophotometricallyby measuring the decrease in the absorbance of DBIPP at 630 nm. Under the optimum conditions (2 x 10(-5) mol L(-1) DBIPP. 4 x 10(-4) mol L"' potassium periodate, 1 x 10(-4) mol L(-1) 1,10-phenanthroline, 0.1 mol L(-1) buffer solution pH 4.0, 70°C, 6 min) manganese(ll) ions can be determined in the range 0.08-5 ng mL(-1) by the fixed-time method with the detection limit of 0.025 ng mL(-1). The developed method is highly sensitive, selective, and simple. The method is based on aqueous extraction of free manganese(II) ions in analysis of some decoctions (fruits of one-styled hawthorn and dog-rose) and infusions (blossoms of German chamo-mile and leaves of spearmint).

Badano katalityczny wpływ jonów manganu(II) na utlenianie nadchloranu l-butylo-3,3-dimetylo-2-[5-(l-butylo-3,3-dimetylo-3H-benzoindolin-2-ylideno)-l,3-pentadienylo]-3H-benzoindolinowego (DBIPP) nadjodanem potasu w obecności 1,10-fenantroliny w słabo kwaśnych roztworach. Reakcję kontrolowano spektrofotometrycznie mierząc zmniejszenie absorbancji DBIPP przy 630 nm. W optymalnych warunkach reakcji (2 x l0(-5) mol L(-1) DBIPP. 4 x 10(-4) mol L(-1) nadjodanu potasu, 1 x 10(-4) mol L(-1) 1,10-fenantroliny. 0. l mol L(-1) roztworu buforu o pH 4.0,70°C, 6 min) jony manganu(II) mogą być oznaczane w zakresie 0.08-5 ng mL(-1) metodą kinetyczną w starym czasie reakcji z granicą wykrywalności 0.025 ng mL(-1). Opracowana metodajest bardzo czulą, selektywna i prosta. Metodę zastosowano z powodzeniem do analizy niektórych odwarów (owoce jednoszyjkowego głogu i dzikiej róży) i naparów (kwiatostany rumianku pospolitego i liście mięty) w celu oznaczania śladowych ilości wolnych jonów manganu(II) bez ich wydzielania oraz do oznaczania manganu całkowitego.

Manganese (II)-1,10-phenanthroline-azo dye-potassium periodate system for kinetic spectrophotometric determination of nanogram levels of manganese

Mutaftchiev K. L.

Bulletin of the Polish Academy of Sciences. Chemistry

2001

Vol. 49, No. 3

193-201

The catalytic effect of manganese (II) on the oxidation of l,3-dimethyl-2 [4-N (N,N-dimethylamino) phenylazo] imidazolium perchlorate, with potassium periodate in the presence of 1,10-phenanthroline in weakly acidic media is studied. The reaction is followed spectrophotometrically by measuring the decrease in the absorbance of the dye at 540 nm. A kinetic method for determination of manganese (II) is developed. Manganese (II) in the range 0.1-4.5 ng cm(-3) can be determined by the fixed-time method. The detection limit is 0.03 ng cm(-3), and the RSD is 1.0% for 2 ng cm(-3). The method is extremely sensitive, highly selective, and simple. It was applied to the determination of manganese in walnuts, monkey-nuts, and hazel-nuts. This is the first attempt to apply a kinetic method to determine manganese in these nuts. The results showed good agreement with those obtained by atomic absorption spectrophotometry.