Simultaneous determination of reversible potential and rate constant for a first-order EC reaction by potential dependent chronoamperometry

1978 ◽  
Vol 50 (4) ◽  
pp. 645-648 ◽  
Author(s):  
Hung-Yuan. Cheng ◽  
Richard L. McCreery
Keyword(s):  
Simultaneous Determination ◽  
Rate Constant ◽  
First Order ◽  
Reversible Potential

scholarly journals UV Spectrophotometric Simultaneous Determination of Paracetamol and Ibuprofen in Combined Tablets by Derivative and Wavelet Transforms

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Vu Dang Hoang ◽  
Dong Thi Ha Ly ◽  
Nguyen Huu Tho ◽  
Hue Minh Thi Nguyen
Keyword(s):  
Simultaneous Determination ◽  
Wavelet Transforms ◽  
Hybrid Approach ◽  
Uv Spectra ◽  
Order Derivative ◽  
First Order ◽  
Spectrophotometric Methods ◽  
Combined Use ◽  
Linear Concentration

The application of first-order derivative and wavelet transforms to UV spectra and ratio spectra was proposed for the simultaneous determination of ibuprofen and paracetamol in their combined tablets. A new hybrid approach on the combined use of first-order derivative and wavelet transforms to spectra was also discussed. In this application, DWT (sym6 and haar), CWT (mexh), and FWT were optimized to give the highest spectral recoveries. Calibration graphs in the linear concentration ranges of ibuprofen (12–32 mg/L) and paracetamol (20–40 mg/L) were obtained by measuring the amplitudes of the transformed signals. Our proposed spectrophotometric methods were statistically compared to HPLC in terms of precision and accuracy.

scholarly journals Simultaneous determination of gatifloxacin and prednisolone acetate in ophthalmic formulation using first-order UV derivative spectroscopy

2017 ◽  
Vol 10 (5) ◽  
pp. 604-610 ◽  
Author(s):  
Rúbia A. Sversut ◽  
Isabella C. Alcântara ◽  
Aline M. Rosa ◽  
Adriano C.M. Baroni ◽  
Patrik O. Rodrigues ◽  
...  
Keyword(s):  
Simultaneous Determination ◽  
Prednisolone Acetate ◽  
First Order ◽  
Derivative Spectroscopy ◽  
Ophthalmic Formulation

Simultaneous Determination of Tramadol and Ibuprofen in Pharmaceutical Preparations by First Order Derivative Spectrophotometric and LC Methods

2008 ◽  
Vol 68 (9-10) ◽  
pp. 843-847 ◽  
Author(s):  
A. B. Thomas ◽  
N. G. Dumbre ◽  
R. K. Nanda ◽  
L. P. Kothapalli ◽  
A. A. Chaudhari ◽  
...  
Keyword(s):  
Simultaneous Determination ◽  
Pharmaceutical Preparations ◽  
Order Derivative ◽  
First Order

Vulcameter Determination of Best Cure

1965 ◽  
Vol 38 (4) ◽  
pp. 757-768 ◽  
Author(s):  
S. D. Gehman ◽  
F. S. Maxey ◽  
S. R. Ogilby
Keyword(s):  
Rate Constant ◽  
Work Load ◽  
Service Performance ◽  
Stress Strain ◽  
First Order ◽  
Testing Laboratories ◽  
Physical Testing ◽  
Strain Testing ◽  
Minimum Number

Abstract Using a continuous cure curve to select a minimum number of stepped cures, it should be possible to vulcanize and test fewer sheets to determine best cure. This procedure is attractive for its potential of expediting the output of physical testing laboratories and especially for reducing the work load of stress-strain testing. Cure curves recorded with the Vulcameter approximated first-order reactions. Equations were derived to calculate the final force and rate constant from recorded force values without carrying the reaction to completion. A chart is suggested to assist in calculating the rate constant. Time for a given fractional rise in force depends only on the rate constant so that a chart for obtaining it is relatively simple. Experience and correlation with service performance in selecting best cures is emphasized. 95% rise times from Vulcameter curves were compared with conventionally selected best cures for a wide variety of compounds. Indications are that experience with the method might reduce the number of test-sheet cures to determine optimum stress-strain properties to one, two, or three depending upon the compound and the exactness required.

scholarly journals Simultaneous Determination of Dapsone and Pyrimethamine by Derivative Spectrophotometry in Pharmaceutical Formulations

2003 ◽  
Vol 86 (2) ◽  
pp. 241-245 ◽  
Author(s):  
M Inés Toral ◽  
Andrés Tassara ◽  
César Soto ◽  
Pablo Richter
Keyword(s):  
Simultaneous Determination ◽  
Signal To Noise Ratio ◽  
Pharmaceutical Formulations ◽  
Derivative Spectrophotometry ◽  
Fast Method ◽  
Signal To Noise ◽  
Zero Crossing ◽  
First Order ◽  
First Derivative

Abstract A simple and fast method was developed for the simultaneous determination of dapsone and pyrimethamine by first-order digital derivative spectrophotometry. Acetonitrile was used as a solvent to extract the drugs from the pharmaceutical formulations, and the samples were subsequently evaluated directly by digital derivative spectrophotometry. The simultaneous determination of both drugs was performed by the zero-crossing method at 249.4 and 231.4 nm for dapsone and pyrimethamine, respectively. The best signal-to-noise ratio was obtained when the first derivative of the spectrum was used. The linear range of determination for the drugs was from 6.6 × 10−7 to 2.0 × 10−4 and from 2.5 × 10−6 to 2.0 × 10−4 mol/L for dapsone and pyrimethamine, respectively. The excipients of commercial pharmaceutical formulations did not interfere in the analysis. Chemical and spectral variables were optimized for determination of both analytes. A good level of repeatability, 0.6 and 1.7% for dapsone and pyrimethamine, respectively, was observed. The proposed method was applied for the simultaneous determination of both drugs in pharmaceutical formulations.

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