Sidika Sungur
Yıldız Technical University
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Featured researches published by Sidika Sungur.
Talanta | 2011
Özlem Aksu Dönmez; Bürge Aşçı; Abdürrezzak Bozdoğan; Sidika Sungur
A simple and rapid analytical procedure was proposed for the determination of chromatographic peaks by means of partial least squares multivariate calibration (PLS) of high-performance liquid chromatography with diode array detection (HPLC-DAD). The method is exemplified with analysis of quaternary mixtures of potassium guaiacolsulfonate (PG), guaifenesin (GU), diphenhydramine HCI (DP) and carbetapentane citrate (CP) in syrup preparations. In this method, the area does not need to be directly measured and predictions are more accurate. Though the chromatographic and spectral peaks of the analytes were heavily overlapped and interferents coeluted with the compounds studied, good recoveries of analytes could be obtained with HPLC-DAD coupled with PLS calibration. This method was tested by analyzing the synthetic mixture of PG, GU, DP and CP. As a comparison method, a classsical HPLC method was used. The proposed methods were applied to syrups samples containing four drugs and the obtained results were statistically compared with each other. Finally, the main advantage of HPLC-PLS method over the classical HPLC method tried to emphasized as the using of simple mobile phase, shorter analysis time and no use of internal standard and gradient elution.
Analytical Letters | 2006
Bürge Aşçı; Güzin Alpdoğan; Sidika Sungur
Abstract A method was established for enrichment of trace levels of Co(II), Ni(II), Fe(II), and Cu(II) ions in aqueous solutions. These metals were quantitatively retained on an Amberlite XAD‐4 column, after complexation with di‐2‐pyridyl ketone thiosemicarbazone (DPKT). After elution with 1 M HNO3 in acetone, concentration of metals were measured by atomic absorption spectrometry. The effect of major cations of drinking and tap water samples on the sorption of metal ions also were investigated. The amount of the analyte metal ions determined after preconcentration was basically in agreement with the added amount. The developed method was used for the determination of trace amounts of metal ions in drinking and tap water samples with good results, such as relative standart deviations below 2% (N=6) and recoveries greater than >95%.
Talanta | 1995
Mahmure Üstün Özgür; Sidika Sungur
Ascorbic acid (AA) has been determined in kiwi, parsley and grapefruit by third order derivative spectrophotometry without using any separation or background correction techniques and reagents. The method is based on the measurement of the distances between two extremum values (peak-to-peak amplitudes) in the third order derivative spectra of the extracts. A metaphosphoric acid (3% w/v)-acetic acid (8% v/v) mixture was found to be the most suitable extraction solution. In the third order derivative spectrum, the extrema of 259.4 nm and 276.2 nm were used for the quantitative determination of AA in kiwi, and the extrema of 227 nm and 237 nm were used for the quantitative determination of AA in parsley and grapefruit. Calibration curves were constructed for the 2.0-10.0 mug ml(-1) concentration range. Relative standard deviations were calculated from the assay results of 14 samples. They were found to be in the ranges of 0.53-2.45% and 0.50-1.41% for the proposed method and the Association of Official Analytical Chemists (AOAC) method, respectively. The obtained results were statistically compared with those of the official method of AOAC using the F test. There was no significant difference between the precisions at a 95% confidence level.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy | 1999
Güzin Alpdoğan; Sidika Sungur
Abstract Sensitive and specific atomic adsorption spectroscopy (AAS) and spectrophotometric methods have been developed for the determination of beta adrenergic blocking drug, metoprolol tartrate.The method is based on the formation of Cu(II) dithiocarbamate complex by derivatization of the secondary amino group of metoprolol with CS 2 and CuCl 2 in the presence of ammonia.The copper-bis(dithiocarbamate) complex was extracted into chloroform and the concentration of metoprolol tartrate was determined directly by spectrophotometric and indirectly by AAS measurement of copper.The two methods developed were applied to the assay of metoprolol tartrate in commercial tablet formulations.The methods were compared statistically with each other and with the high performance liquid chromatography (HPLC) method of USPXXII using t - and F -tests.
Analytical Letters | 1999
Güzin Alpdoğan; Sidika Sungur
ABSTRACT An Indirect AAS method has been developed for the determination of analgesic-inflammatory drugs, mefenamic acid, flufenamic acid and diclofenac sodium. The method depends on the complexation with copper (II) ammine sulphate. The complex was extracted into chloroform and the concentrations of substances were determined indirectly by AAS measurement of copper, after re-extraction into 0.3 N nitric acid solution. The developed method was applied to the assay of the drug substances in commercial tablet formulations. The results were statistically compared with those obtained by HPLC method by t- and F-tests at 95% confidence level. Calculated t and F values were both lower than the table values.
Journal of Analytical Chemistry | 2010
Bürge Aşçı; Ö. A. Dönmmez; Abdürrezzak Bozdoğan; Sidika Sungur
Abstract25-1 fractional factorial design was applied to optimize the chromatographic conditions of the RP-HPLC determination of ibuprofen, pseudoephedrine hydrochloride, chlorpheniramine maleate, and nipagen in syrup preparation. All the factors that affect the determination of components and their interactions were investigated. pH, flow rate and solvent ratios for three steps of gradient profile were regarded as factors to be investigated in two levels. The resolution was chosen as analytical response. The limit of quantitations (10 s/m) were found as 0.9, 1.0, 0.4, and 0.12 μg/mL for ibuprofen, pseudoephedrine hydrochloride, chlorpheniramine maleate, and nipagen, respectively.
Turkish Journal of Chemistry | 2002
Mahmure Üstün Özgür; Sidika Sungur
A rapid and sensitive analytical method was developed for the spectrophotometric assay of prazosin hydrochloride. The method is based on the formation of a coloured derivative between the drug and 1,2-naphthoquinone-4- sulphonic acid sodium salt (NQS). The reaction proceeds quantitatively at pH 4.5 and 70°C for 40 min. After the extraction of the derivative with chloroform: n-butanol (3:1), the absorbance was measured at 400 nm. The method was applied to commercially available tablets and the results were statistically compared with those obtained by ultraviolet spectrophotometric and differential pulse polarographic methods using t- and F-tests.
Reviews in Analytical Chemistry | 2007
Fatma Aytan; Güzin Alpdoğan; Sidika Sungur
Lisinopril, a new drug substance, is an angiotensin-converting enzyme (ACE) inhibitor. In this study, we investigate the high pressure liquid chromatographic pH effect on the solution stability of lisinopril. Lisinopril solutions of 75 pg/ml were prepared in various buffer solutions in the range of pH = 2-8. These solutions were heated in an oven at 80°C for various hours. After these periods the solutions were removed and cooled immediately. Then, ΙΟμΙ of the solution was injected into a high pressure liquid chromatographic system containing a Bondapak C18 reversed phase column and a variable wavelength UV visible absorbance detector. The separation was performed with pH = 5 phosphate buffer acetonitril triethylamine (90 : 10 : 0.1) mixture as isocratic mobile phase. The detector was operated at 209 nm. The investigation of the chromatograms and lisinopril peak areas indicated that pH has a significant effect on the stability of lisinopril in aqueous solution and decomposition rate of lisinopril is increased by the decreasing pH. Pseudo first order rate constants were calculated using the time log (peak area) plots. * Corresponding author e-mail : [email protected]
Analytical Letters | 2010
Hale Berber; Güzin Alpdoğan; Bürge Aşçı; Hüseyin Yıldırım; Sidika Sungur
Crosslinked glycidylmethacrylate-methylmethacrylate-divinylbenzen (GMA-MMA-DVB) microspheres were prepared by suspension polymerization. The GMA-MMA-DVB microspheres with an average size of 150–300 μm and surface area of 1.51 m2g−1 were functionalized with 2-aminothiazole (ATAL). The affinity of the functionalized microspheres for copper, iron, aluminum, lead, cobalt, and nickel ions was examined. The effects of pH, resin amount, shaking time, type, and volume of the elution solution on the sorption and desorption properties of functionalized microspheres for these metal ions were investigated using the batch method. Sorption capacities (0.97–1.12 mmolg−1), quantitation limits (2.6–3.0 ppb) and recoveries (90–99%) were calculated.
Analytical Letters | 1997
Güzin Alpdoğan; Sidika Sungur
Abstract An HPLC method has been developed for the determination of the beta adrenergic blocking drug metoprolol tartrate. The method is based on the formation of a Cu (II) - dithiocarbamate complex by precolumn derivatization of secondary amino group of metoprolol with CS2 and CuCl2 in the presence of ammonia. The complex is extracted into chloroform and injected into the chromatograph. Chromatographic separation was performed by a RP (μ Bondapak C18) column with methanol - pH 5.8 phosphate buffer (80 : 20) as the isocratic mobile phase. A variable wavelength absorbance detector (λ = 275 nm) was used. A linear relationship was obtained between peak areas and metoprolol tartrate concentrations over the range of 35 - 180 nmol ml−1. The method was applied to the analysis of metoprolol tartrate tablets and the results were statistically compared with those obtained by official method using t - and F - tests.
