WoS İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8653

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Author: search.filters.author.Dinc, ErdalPublisher: search.filters.publisher.Elsevier

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Now showing 1 - 6 of 6
  • Article
    Citation - WoS: 2
    Citation - Scopus: 2
    A New Approach To the Characterization of the Nano-Surface Structure by Using Factor Analysis
    (Elsevier, 2012) Baleanu, Dumitru; Solak, Ali Osman; Eksi, Haslet; Guzel, Remziye; Dinc, Erdal
    The study provides a new approach to explore the existence of a nanostructure on the benzoic acid-modified glassy carbon electrode (BA-GC) system by applying factor analysis with varimax rotation of factors. The infrared spectra (IR) spectra of the bare glassy carbon electrodes (GC) and the BA-GC electrode systems with benzoic acid-nanofilm (BA-FILM) were obtained by using 10 different surface modification experiments. The IR data of the bare GC, BA-GC and BA-FILM were categorized into three series corresponding to the GC, BA-GC and BA-FILM. The factor analysis method was separately applied to each group to extract the factor loadings. By making use of these loadings, the rotated factor loadings corresponding to the first two factors were computed to estimate the relationship among and within groups. The results provided by the factor analysis method indicate the existence of the BA-FILM on the BA modified glassy carbon electrode. (C) 2011 Elsevier B.V. All rights reserved.
  • Article
    Citation - WoS: 10
    Citation - Scopus: 11
    Fractional and Continuous Wavelet Transforms for the Simultaneous Spectral Analysis of a Binary Mixture System
    (Elsevier, 2011) Buker, Eda; Baleanu, Dumitru; Dinc, Erdal
    A combined application of the fractional wavelet transform-continuous wavelet transform to the quantitative resolution of the overlapping signals of olmesartan modoxomil and hydrochlorothiazide in a binary mixture was presented. In this work the recorded absorption signals of two compounds in the range 4-12 mu g/mL olmesartan and 2-10 mu g/mL hydrochlorothiazide were processed by the fractional transform approach and with the continuous wavelet transform, respectively. The proposed combined complex signal analysis method was validated by analyzing the synthetic binary mixtures of the related compound. By analyzing the statistical parameters we conclude that the new approach is suitable to be used for the quality control of the commercial samples of compounds. (C) 2011 Published by Elsevier B.V.
  • Article
    Citation - WoS: 21
    Citation - Scopus: 23
    New Approach for Simultaneous Spectral Analysis of a Complex Mixture Using the Fractional Wavelet Transform
    (Elsevier, 2010) Demirkaya, Fatma; Baleanu, Dumitru; Kadioglu, Yuecel; Kadioglu, Ekrem; Dinc, Erdal
    Fractional wavelet transform (FWT) is a powerful toot in order to extract largest analytical information from the spectral bands. For the above reason, the combined applications of fractional wavelet transform with principal component regression (PCR) and partial least squares (PLS) calibrations are performed for the quantitative analysis of a pharmaceutical mixture containing trimethoprim (TMP) and sulphamethoxazole (SMX). One interesting example of complex pharmaceutical mixture is given by the multi-component pharmaceutical sample having constant matrix content. In this study, the absorption spectra of the related compounds and their samples were processed by fractional wavelet transform. In the following procedure, FWT-coefficients obtained in the above step are used to construct the PCR and PLS calibrations. These hybrid mathematical approaches are denoted as FWT-PCR and FWT-PLS calibrations. FWT-PCR and FWT-PLS obtained by using the FWT-coefficients for the quantitative analysis of TMP and SMX gives the higher accurate and precise results than classical PCR and PLS based on the use of the original absorbance values. (C) 2009 Elsevier B.V. All rights reserved.
  • Article
    Citation - WoS: 37
    Citation - Scopus: 43
    Multivariate Analysis of Paracetamol, Propiphenazone, Caffeine and Thiamine in Quaternary Mixtures by Pcr, Pls and Ann Calibrations Applied on Wavelet Transform Data
    (Elsevier, 2008) Baleanu, Dumitru; Ioele, Giuseppina; De Luca, Michele; Ragno, Gaetano; Dinc, Erdal
    The quantitative resolution of a quaternary pharmaceutical mixture consisting of paracetamol, propiphenazone, caffeine and thiamine was performed by the simultaneous use of fractional wavelet transform (FWT) with principal component regression (PCR), partial least squares (PLS) and artificial neural networks (ANN) methods. A calibration set consisting of 22 mixture solutions was prepared by means of an orthogonal experimental design and their absorption spectra were recorded in the spectral range of 210.0-312.3 nm and then transferred into the fractional wavelet domain and processed by FWT. The chemometric calibrations FWT-PCR, FWT-PLS and FWT-ANN were computed by using the relationship between the coefficients provided by FWT method and the concentration data from calibration set. An external validation was carried out by applying the developed methods to the analysis of synthetic mixtures of the related compounds, obtaining successful results. The models were finally used to assay the studied drugs in the commercial pharmaceutical formulations. (c) 2008 Elsevier B.V. All rights reserved.
  • Article
    Citation - WoS: 18
    Citation - Scopus: 18
    Characterization of a Benzoic Acid Modified Glassy Carbon Electrode Expressed Quantitatively by New Statistical Parameters
    (Elsevier, 2009) Baleanu, Dumitru; Dinc, Erdal; Solak, Ali Osman; Nigmatullin, Raoul R.
    The main aim of this study is to characterize the nanosurface of the benzoic acid modified glassy carbon (GC) electrode by using a new statistical approach. In this study, the electrode surfaces were modified by cyclic voltametry in the potential range of +0.4 and -0.8 V at a scan rate 200 mV s(-1) for four cycles versus Ag/Ag+ electrode in acetonitrile containing 0.1 M tetrabutylammonium tetraflouroborate (TBATFB). FT-IR spectra of the surface modifier molecules in both solid (GC and nanofilm (GC-benzoic acid)) forms were recorded in the spectral range 600-4000 cm(-1). The FT-IR spectra of p-aminobenzoic acid were obtained by using KBr pellets. The above FT-IR spectra of both GC and its nanofilm with benzoic acid were processed by new statistical approach to reach optimal smoothing trend for the characterization of the modified electrode surface consisting of the nanofilm of GC-benzoic acid. In the frame of new statistical approach all measured spectra have been 'read' in terms of a set of universal statistical parameters. (C) 2008 Elsevier B.V. All rights reserved.
  • Article
    Citation - WoS: 49
    Citation - Scopus: 55
    Continuous Wavelet and Derivative Transforms for the Simultaneous Quantitative Analysis and Dissolution Test of Levodopa-Benserazide Tablets
    (Elsevier, 2007) Kaya, Sueha; Doganay, Tanver; Baleanu, Dumitru; Dinc, Erdal
    Simultaneous analyses and dissolution tests of levodopa-benserazide tablets were carried out by continuous wavelet transform (CWT) and classic derivative spectrophotometry (DS) without using any chemical separation step. The developed two spectrophotometric resolutions are based on the transformation of the original UV spectra. The original absorption spectra of levodopa and benserazide in the concentration range of 1-80 mu g/mL and 5-240 mu g/mL in USP simulated gastric juice were registered in the spectral range of 250-310 nm, respectively. Various wavelet families and different spectrophotometric derivative orders were tested to find the optimal signal processing for obtaining desirable calibration graphs and reliable determinations of the investigated drugs. Under the optimized conditions of the methods, symlets wavelet family using a = 128 with sixth order (SYM6-CWT) and the first derivative transform with Delta lambda = 10 nm were identified as optimal signal processing methods for the determinations and dissolution tests. The calibration functions for each drug were obtained by measuring the values of the CWT and derivative amplitudes. The validation of the developed methods was confirmed by analyzing various synthetic mixtures of the investigated drugs. Mean recovery values were found between 99.1% and 104.7% for DS and 100% and 102.9% for CWT, respectively for determination of BEN and LEV in synthetic mixtures. Each developed approaches were successfully applied to the simultaneous determination and dissolution test of levodopa and benserazide in their commercial tablets and a good agreement was observed. (c) 2007 Elsevier B.V. All rights reserved.