Determination of Rate Constants in Second-Order Kinetics Using UV-Visible Spectroscopy

2001 ◽  
Vol 55 (1) ◽  
pp. 77-83 ◽  
Author(s):  
Sabina Bijlsma ◽  
Hans F. M. Boelens ◽  
Age K. Smilde
Keyword(s):  
Rate Constants ◽  
Second Order ◽  
Visible Spectroscopy ◽  
Uv Visible

Determination of rate constants of redox reactions of second order from current-less potential-time curves by a simplified graphical-numerical method

1983 ◽  
Vol 48 (5) ◽  
pp. 1358-1367 ◽  
Author(s):  
Antonín Tockstein ◽  
František Skopal
Keyword(s):  
Numerical Method ◽  
Explicit Form ◽  
Rate Constant ◽  
Optimization Algorithm ◽  
Rate Constants ◽  
Redox Reactions ◽  
Second Order ◽  
Wide Region ◽  
Recurrent Formula

A method for constructing curves is proposed that are linear in a wide region and from whose slopes it is possible to determine the rate constant, if a parameter, θ, is calculated numerically from a rapidly converging recurrent formula or from its explicit form. The values of rate constants and parameter θ thus simply found are compared with those found by an optimization algorithm on a computer; the deviations do not exceed ±10%.

Determination of the Nucleophilicity of Tricarbonyliron Coordinated Cyclohepta-1,3,5-triene

1999 ◽  
Vol 64 (11) ◽  
pp. 1770-1779 ◽  
Author(s):  
Herbert Mayr ◽  
Karl-Heinz Müller
Keyword(s):  
Gibbs Energy ◽  
Ambient Temperature ◽  
Rate Constants ◽  
Second Order ◽  
Order Rate ◽  
Electrophilic Additions ◽  
Kinetics Of

The kinetics of the electrophilic additions of four diarylcarbenium ions (4a-4d) to tricarbonyl(η4-cyclohepta-1,3,5-triene)iron (1) have been studied photometrically. The second-order rate constants match the linear Gibbs energy relationship log k20 °C = s(E + N) and yield the nucleophilicity parameter N(1) = 3.69. It is concluded that electrophiles with E ≥ -9 will react with complex 1 at ambient temperature.

The use of UV-visible spectroscopy for the determination of hydrophobic interactions between neuropeptides and membrane model systems

Biopolymers ◽  
1992 ◽  
Vol 32 (8) ◽  
pp. 1061-1064 ◽  
Author(s):  
John K. Young ◽  
William H. Graham ◽  
Debbie J. Beard ◽  
Rickey P. Hicks
Keyword(s):  
Hydrophobic Interactions ◽  
Model Systems ◽  
Membrane Model ◽  
Visible Spectroscopy ◽  
Uv Visible

Kinetic Study on Oxidation of Thiodipropionic Acid by Iron (III)- bipyridine Complex

2016 ◽  
Vol 15 (2) ◽  
pp. 33-44
Author(s):  
John K Adaikalasamy ◽  
Selva A Priya ◽  
Sunaja K R Devi
Keyword(s):  
Kinetic Study ◽  
Rate Constants ◽  
Second Order ◽  
Aqueous Acetonitrile ◽  
Order Rate ◽  
Uv Visible

Iron(III)-bipyridine complex was prepared andcharacterized by UV-Visible spectrophotometer. Kineticstudy was carried out by using this iron(III)-bipyridinewith thiodipropionic acid in aqueous acetonitrile solution.The reaction was optimized by studying the effect onsubstrate, solvent, oxidant, acidity and temperature. Firstorder, second order rate constants and activationparameters were calculated. The above reaction wasfound to be second order and proceeded through electrontransfer from thiodipropionic acid to iron(III)-bipyridinecomplex. The product was characterized and confirmedby IR and NMR spectroscopy.Keywords: Thiodipropionic acid, Iron(III)-bipyridine complex,kinetic study of Iron(III)-bipyridyl complexes.

Formation and spectra of flavin radicals in the presence of β-mercaptoethanol at pH 9 and 10

1984 ◽  
Vol 62 (3) ◽  
pp. 580-585 ◽  
Author(s):  
Parminder S. Surdhar ◽  
Rizwan Ahmad ◽  
David A. Armstrong
Keyword(s):  
Rate Constant ◽  
Rate Constants ◽  
Order Rate Constant ◽  
Second Order ◽  
Radical Species ◽  
Spectral Changes ◽  
Order Rate ◽  
Visible Spectra ◽  
Uv Visible ◽  
Presence And Absence

Spectral changes and rates of reaction of flavins and several radical species have been investigated at pH 7, 9, and 10 in the presence and absence of β-mercaptoethanol. The radicals •CO2−, eaq−, and [Formula: see text] reacted with FAD at pH 10 to give a spectrum of FAD •Fl− with rate constants of 7 ± 1 × 108 and 4 ± 1 × 108 M−1 s−1 for •CO2− and [Formula: see text] respectively. At pH 7 only •FlH was observed and at pH 9 a mixture of •FIH and •Fl−.Interactions between flavin radicals and sulphydryl at 10−4 M concentration did not cause perturbations in the uv–visible spectra until either the radical and/or the sulphydryl were ionized. With FAD at pH 9 or 10 and LFl at pH 10 the 370 nm peak of •Fl− was enhanced by about 15% and a second larger growth occurred near 450 nm in the presence of 10−4 to 10−2 M sulphydryl. We attribute this to the formation of labile intermediate RSHFl•−, which must also be involved in the reduction of Fl by [Formula: see text] at pH 9 or 10.The second order rate constant k13 for reaction of [Formula: see text] with FAD at pH 9 and 10 was found to be 4.2 ± 0.5 × 108 M−1 s−1 and 2.0 ± 0.4 × 108 M−1 s−1 respectively. The rate constant for the reaction between [Formula: see text] and LFl at pH 10 was slightly faster, 7 ± 1 × 108 M−1 s−1, probably reflecting the fact that LFl lacks the bulky negatively charged adenine dinucleotide group of FAD.

Determination of pKa of felodipine using UV–Visible spectroscopy

2013 ◽  
Vol 115 ◽  
pp. 887-890 ◽  
Author(s):  
M.M. Pandey ◽  
A. Jaipal ◽  
A. Kumar ◽  
R. Malik ◽  
S.Y. Charde
Keyword(s):  
Visible Spectroscopy ◽  
Uv Visible

scholarly journals DEVELOPMENT AND VALIDATION OF UV-SPECTROPHOTOMETRIC METHODS FOR DETERMINATION OF GEMCITABINE HYDROCHLORIDE IN BULK AND POLYMERIC NANOPARTICLES

2017 ◽  
Vol 9 (5) ◽  
pp. 60 ◽  
Author(s):  
Taranjit Kaur ◽  
Sukhjinder Kaur ◽  
Parminderjit Kaur
Keyword(s):  
Polymeric Nanoparticles ◽  
Visible Spectroscopy ◽  
International Conference ◽  
Spectrophotometric Methods ◽  
Gemcitabine Hydrochloride ◽  
Double Beam ◽  
Uv Visible ◽  
Formulation Analysis ◽  
Development And Validation

Objective: The objective of the present work was to develop and validate a novel, specific, precise and reliable method for estimation of gemcitabine hydrochloride in bulk and polymeric nanoparticles using UV-visible spectroscopy method.Methods: The UV-Visible spectrophotometric determination was performed with double beam Systronics UV-visible spectrophotometer; model UV-2201 (India). The proposed methods were validated for various parameters like linearity, precision, accuracy, robustness, ruggedness, detection, quantification limits, and formulation analysis as per international conference on harmonization (ICH) guidelines.Results: The method was based on measurement of absorbance at wavelength maxima i.e. 267.2 nm, λmax of the drug in distilled water, phosphate buffer pH 6.8 and 7.4. The method obeyed Beer Lambert’s law in the concentration range of 5-30 µg/ml andR2-value was found to be 0.999. Moreover, the % drug recovered from polymeric nanoparticles was found to be 97.97%.Conclusion: According to results, the currently developed method shows compliance with acceptance criteria with Q2 (R1) and international conference on harmonization (2005) guidelines, because the % RSD was found to be less than 2%. The developed method was simple, accurate and précised.

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