Browsing by Author "Pektas, Goezde"

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Citation - WoS: 5
Citation - Scopus: 9
Combined Application of Continuous Wavelet Transform-Zero Crossing Technique in the Simultaneous Spectrophotometric Determination of Perindopril and Indapamid in Tablets
(Soc Brasileira Quimica, 2009) Pektas, Goezde; Baleanu, Dumitru; Dinc, Erdal; Baleanu, Dumitru; Matematik
Signal processing methods based on the combined use of the continuous wavelet transform (CWT) and zero-crossing technique were applied to the simultaneous spectrophotometric determination of perindopril (PER) and indapamide (IND) in tablets. These signal processing methods do not require any priory separation step. Initially, various wavelet families were tested to identify the optimum signal processing giving the best recovery results. From this procedure, the Haar and Biorthogonal 1.5 continuous wavelet transform (HAAR-CWT and BIOR 1.5-CWT, respectively) were found suitable for the analysis of the related compounds. After transformation of the absorbance vectors by using HAAR-CWT and BIOR 1.5-CWT, the CWT-coefficients were drawn as a graph versus wavelength and then the HAAR-CWT and BIOR 1.5-CWT spectra were obtained. Calibration graphs for PER and IND were obtained by measuring the CWT amplitudes at 231.1 and 291.0 rim in the HAAR-CWT spectra and at 228.5 and 246.8 nm in BIOR 1.5-CWT spectra. respectively. In order to compare the performance of HAAR-CWT and BIOR 1.5-CWT approaches, derivative spectrophotometric (DS) method and HPLC as comparison methods, were applied to the PER-IND samples. In this DS method, first derivative absorbance values at 221.6 for PER and 282.7 nm for IND were used to obtain the calibration graphs. The validation of the CWT and DS signal processing methods was carried out by using the recovery study and standard addition technique. In the following step, these methods were Successfully applied to the commercial tablets containing PER and IND compounds and good accuracy and precision were reported for the experimental results obtained by all proposed signal processing methods.
Citation - WoS: 11
Citation - Scopus: 14
Continuous Wavelet Transform and Derivative Spectrophotometry for the Quantitative Spectral Resolution of a Mixture Containing Levamizole and Triclabendazole in Veterinary Tablets
(Freund Publishing House Ltd, 2009) Pektas, Goezde; Baleanu, Dumitru; Dinc, Erdal
Continuous wavelet transform (CWT) and derivative spectrophotometry (DS) were used for the quantitative determination of levamizole (LE) and triclabendazole (TR) in the commercial veterinary tablets without any priory separation step. Among all available wavelet families, biorthogonal continuous wavelet family (BIOR 3.9-CWT) with dilation parameter a=132 was found to be the one which provides the optimal signal processing tool for the reliable recovery results. BIOR 3.9-CWT was applied to the absorption data consisting of 1024 data points in the spectral range of 224-326.3 nm and CWT coefficients were plotted versus wavelength to obtain BIOR 3.9-CWT spectra. Calibration graphs for LE and TR compounds were calculated by considering the CWT amplitudes. DS approach was used for checking the results obtained by BIOR 3.9-CWT method. For DS method, third derivative spectrophotometry was found to be suitable for the determination of the related compounds. The performance of both analytical methods was verified by analyzing several synthetic mixtures containing LE and TR and by using the standard addition method. Good accuracy, precision and selectivity were reported. CWT and DS were successfully applied to the analysis of the commercial veterinary tablets.