Characteristics of methods for the simultaneous determination of catalysts by first-order inhibition kinetics

1989 ◽  
Vol 61 (22) ◽  
pp. 2551-2556 ◽  
Author(s):  
Carol P. Fitzpatrick ◽  
Harry L. Pardue
2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Vu Dang Hoang ◽  
Dong Thi Ha Ly ◽  
Nguyen Huu Tho ◽  
Hue Minh Thi Nguyen

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.


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 ◽  
...  

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 ◽  
...  

2003 ◽  
Vol 86 (2) ◽  
pp. 241-245 ◽  
Author(s):  
M Inés Toral ◽  
Andrés Tassara ◽  
César Soto ◽  
Pablo Richter

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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