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1

Highly sensitive chemiluminescence method for determination of indomethacin using permanganate-formaldehyde system

Fu Z., Wang L.

Chemia Analityczna

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2009

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Vol. 54, No. 2

163-172

EN

A highly sensitive flow injection chemiluminescent method for determination of indomethacin has been proposed. During oxidation of indomethacin by KMnO4 in polyphosphoric acid medium, chemiluminescence emission was observed, which could be enhanced more than 100 times in the presence of 4% formaldehyde. The chemiluminescence mechanism was investigated and two emitters were identified. The proposed strategy allowed for sample assay rate of 100 per l h in an automatic mode in combination with flow injection analysis. Indomethacin could be determined over the concentration range 1.0x109-1.0x 10-1 g mL<-sub>-1 with the detection limit (3σ) of 6.0 x 10<-sub>-10 g mL<-sub>-1. The relative standard deviation for determination of 1.0 x 10<-sub>-8 g mL<-sub>-1 indomethacin (n = 11) was 2.3%. The proposed method has been successfully applied to the analysis of a commercial pharmaceutical formulation without any sample pretreatment and to biological samples after their clean-up by solidphase extraction.

PL

Do oznaczania indometacyny w przepływie zaproponowano wysoko czułą metodę wstrzy-kową wykorzystującą chemiluminescencję, obserwowaną podczas utleniania indometacyny przez KMnO4 w kwasie polifosforowym. Jej intensywność wzrastała w obecności 4% formaldehydu. Badano mechanizm powstawania chemiluminescencji i zidentyfikowano jej dwa źródła. Opracowana metoda pozwalała na zbadanie 100 próbek w ciągu godziny. Indome-tacynę można by ło oznaczy ć w zakresie stężeń 1.0x 109—1.0 x l.0<-sub>-6 g mL<-sub>-1. Granicę wykrywalności (3σ) określono jako 6.0 x l0<-sub>-9 g mL<-sub>-1. Zaproponowaną metodę zastosowano z powodzeniem do analizy handlowych preparatów farmaceutycznych bez potrzeby wstępnego przygotowania próbki. Zastosowano ją również do analizy próbek biologicznych po ich oczyszczeniu metodą ekstrakcji z fazy stałej.

2

Study of Permanganate Ion Transfer Across an Electrified Water/Nitrobenzene Interface

Heli H., Shamsipur M., Mousavi M.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 2

313-323

EN

The transfer of permanganate anion across a water/nitrobenzene interface has been studied by cyclic voltammetry and chronopotentiometry techniques. The diffusion coefficient of the species in aqueous phase was obtained by means of both cyclic voltammetry (DW = 2.75x10-5cm2 s-1) and chronopotentiometry (DW = 2.79x10-5cm2 s-1). The standard potential of transfer was obtained as deltaE0' = -198 mVand the transfer coefficient has also been calculated from the Tafel slope as alfa = 0.4. The effect of temperature on the ion transfer process was studied over a wide range (10-70 graduate C). The Gibbs activation energy of the ion transfer across the interface (deltaG = 12.09 kJ mol-1) and the Gibbs activation energy of ion transport in the bulk of aqueous solution (deltaG = 12.58 kJ mol-1) have been obtained from the temperature dependence of transfer rate data.

3

Kinetic methods of determination of atenolol in pure compound and in pharmaceutical formulations

Hiremath G. C., Mulla R. M., Nandibewoor S. T.

Chemia Analityczna

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2005

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Vol. 50, No. 2

449-455

EN

A sensitive and rapid kinetic method for the determination of atenolol in bulk drugs, pharmaceutical preparations, and urine and blood samples has been developed. The method is based on the oxidation of atenolol by permanganate in alkaline media. The results were compared with the values obtained with the official method. The differences between them were statistically insignificant, as t- and F-tests have revealed. No interference from the commonly used excipients was observed.

PL

Opracowano czułą i szybką kinetyczną metodę oznaczania atenololu w substancji i w formie farmaceutycznej oraz we krwi i w moczu. Metoda jest oparta na utlenianiu atenololu nadmanganianem w środowisku alkalicznym. Wyniki otrzymane za pomocą proponowanej metody porównano, używając statystycznych testów Studenta (t) i Fishera (F), z wynikami otrzymanymi oficjalnie przyjętą metodą. Obie metody dały zgodne rezultaty. Nie zaobserwowano interferencji ze strony popularnych farmaceutycznych substancji pomocniczych.

4

Carbon-13 fractionation in the oxidation of propionate of natural isotopic composition with permanganate and manganate

Zieliński M., Fry A., Zielińska A., Ogrinc N., Papiernik-Zielińska H., Kobal I.

Nukleonika

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2000

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Vol. 45, nr 4

221-224

EN

Carbon-13 fractionation in the oxidation of sodium propionate of natural isotopic composition with permanganate in water solution and with manganate in alkaline solution has been investigated and compared with carbon-14 kinetic isotope effects in the oxidation of (3-14C) – and (2-14C) propionate with permanganate. The experimental carbon-13 isotope ratios, R(13C/12C)cumul., corrected for dilution of R(13C/12C)a by carbon dioxide derived from all external sources and by carbon dioxide derived from (C-1) and from (C-3) of propionate at its complete and partial oxidations, used for calculation of 13C alfa KIE, provided the carbon-13 isotope effects corresponding to initial oxidation of alpha carbon, which correlate well with (2-14C) KIE determined previously, (k12/k13 -1)?100 ? 1/2(k12/k14 -1)?100 ? 1/2(4.6š0.3) at 373 K. The possibility of extension of isotope ratio measurements, using modern double collector mass spectrometers, from geochemical, biomedical, agriculture and environmental research to carbon-13 isotope effects studies in chemical organic reactions is briefly discussed.

5

Kinetics and mechanism of oxidation of L-phenylalanine by alkaline permanganate

Panari R.G., Chougale R.B., Nandibewoor S.T.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 1

99-107

EN

The data suggest that the oxidation of L-phenylalanine proceeds via the formation of a complex between L-phenylalanine and permanganate which decomposes slowly, followed by a fast reaction between the free radical of L-phenylalanine and another molecule of permanganate to give the products. The reaction constants involved in the mechanism are derived. There is a good agreement between the observed and calculated rate contants at varying conditions of experiments. The activation parameters are computed with respect to the slow step of the mechanism.