INDIRECT SPECTROPHOTOMETRIC DETERMINATION OF CAPSAICINOIDS INCapsicumPEPPERS USING THE REACTION OF COMPLEX Co(II) WITH 4-(2-PYRIDYLAZO) RESORCINOL
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چکیده
منابع مشابه
Spectrophotometric determination of acidity constants of 4-(2-pyridylazo)resorcinol in binary methanol–water mixtures
The acidity constants of 4-(2-pyridylazo)resorcinol (PAR, Scheme 1) in binary mixtures of methanol–water at 25 ◦C and an ionic strength of 0.1 M have been determined spectrophotometrically. DATa ANalysis (DATAN) program applied for determination of acidity constants. As percent of methanol increases in solvent mixtures the pKa constants also increased. There is linear relationship between acidi...
متن کاملSolid-phase spectrophotometric determination of trace amounts of vanadium at sub-ng/ml level with 4-(2-pyridylazo)resorcinol.
Solid-phase spectrophotometry has been applied to analysis for trace amounts of vanadium. Vanadium was sorbed in a styrene-divinylbenzene-type anion-exchanger Dowex 1-X8 as a vanadium-4-(2-pyridylazo)resorcinol complex. Resin phase absorbances at 562 and 800 nm were measured directly which allowed the determination of vanadium in the range of 0.1-2.4 ng/ml with a RSD of 1.5%. The method has bee...
متن کاملMultiwavelength spectrophotometric determination of protolytic constants of 4-(2-pyridylazo) resorcinol (PAR) in binary DMF-water mixtures.
A multiwavelength spectrophotometric titration method was applied to study the protolytic constants of 4-(2-pyridylazo) resorcinol(PAR), in binary DMF+water mixtures. UV-vis absorption spectra of PAR solution were recorded in the course of pH-metric titration of acidic solutions of PAR with standard base solution. The protolytic equilibrium constants, spectral profiles, concentration diagrams a...
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The complexation reactions between 4-(2-pyridy1azo)-resorcinol and Cd ,H g and Pb io ns have been investigated in acetonitrile-dimethyEomamide mixtures at various temperatures using a spectrophotometric technique. The stoichiometry and the formation constants of the complexes formed in solution were calculated by computer refinement of absorbance-mole ratio data using nonlinear least-square ...
متن کاملSpectrophotometric Studies on the Protonation and Nickel Complexation Equilibria of 4-(2-Pyridylazo) Resorcinol using Global Analysis in Aqueous Solution
A protonação e complexação de Ni(II) por 4-(2-piridilazo) resorcinol (PAR) em força iônica 0,1 mol L KNO 3 a 25 °C, foram estudadas por análise global. Em titulações espectrofotométricas, a dependência linear ou quase linear da concentração e a existência de espécies em menores concentrações podem causar dificuldades na avaliação dos dados. Espectros de absorção e as correspondentes constantes ...
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ژورنال
عنوان ژورنال: Química Nova
سال: 2014
ISSN: 0100-4042
DOI: 10.5935/0100-4042.20140100