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    Aflatoxin species: their health effects and determination methods in different foodstuffs
    (Sciendo, 2012) Bakirdere, Sezgin; Bora, Selin; Bakirdere, E. Gulhan; Aydin, Firat; Arslan, Yasin; Komesli, O. Tarik; Aydin, Isil
    Carcinogenic and mutagenic properties of aflatoxin species are known in literature. Their intake over a long time period might be health-dangerous for human even at trace levels. It is well known that different foodstuffs can be contaminated by aflatoxin species through growing and storage. Due to the serious health effects, sensitive determination of aflatoxin species in any matrices related with the human being is very crucial at trace levels. In literature, there are sensitive techniques to analyze the different samples for the contents of their aflatoxin species. Each technique has some advantages and disadvantages over the other techniques. This review aims to summarize the different health effects of aflatoxin species, development of analytical techniques and applications of developed techniques in a variety of matrices.
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    Determination of indium using vortex assisted solid phase microextraction based on oleic acid coated magnetic nanoparticles combined with slotted quartz tube-flame atomic absorption spectrometry
    (Elsevier Science Bv, 2018) Celik, Birgul; Akkaya, Erhan; Bakirdere, Sezgin; Aydin, Firat
    A solid phase microextraction (SPME) method combined with slotted quartz tube-flame atomic absorption spectrometry (SQT-FAAS) was developed and optimized for the extraction and the determination of trace indium in different matrices. The method relies upon SPME that uses oleic acid coated magnetite nanoparticles (MNPs) followed by analysis with SQT mounted FAAS. After the enhancement in sensitivity by means of SPME, further improvement in sensitivity was provided by SQT which improves the detection power of conventional FAAS. The easy separation of extracted indium from the media was facilitated using an external magnetic field. Some effective parameters on the development of the method such as pH of the analyte solution, amount of eluent, amount of MNPs were optimized to obtain maximum absorbance value at each optimization step in order to achieve an improved detection power. Under the optimum experimental and instrumental conditions, the enhancement factor of 44 was obtained where the limit of detection and the limit of quantification were found to be 6.02 mu g/L and 20.06 mu g/L, respectively. Recovery tests were also studied in order to demonstrate the accuracy of the developed analytical method and satisfactory outcomes were obtained.
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    Effects of dietary boron on cervical cytopathology and on micronucleus frequency in exfoliated buccal cells
    (Wiley, 2007) Korkmaz, Mehmet; Uzgören, Engin; Bakirdere, Sezgin; Aydın, Fırat; Ataman, O. Yavuz
    Recent evidence indicates that boron and borates may have anticarcinogenic properties. In this study, we have investigated the incidence of adverse cytological findings in cervical smears and the micronucleus (MN) frequency in women living in boron-rich and boron-poor regions. Cervical smears were prepared from 1059 women with low socioeconomic status; 472 of the women lived in relatively boron-rich rural areas, while 587 lived in relatively boron-poor regions. The average and standard deviation values for the age of the women screened with the cervical Pap smear test were 41.55 +/- 8.38. The mean dietary intake of boron was 8.41 mg/day for women from the boron-rich regions, and 1.26 mg/day for women living in the boron-poor regions (P < 0.0001). Women from the boron-rich regions had no cytopathological indications of cervical cancer, while there were cytopathological findings for 15 women from the boron-poor areas (chi(2) = - 10.473, P < 0.05). Sixty women, 30 from each region, were chosen for evaluating MN frequencies in exfoliated buccal cells. MN frequencies for women from the boron-rich and boron-poor regions were not significantly different (t = -0.294, P > 0.05). Also, there were no significant correlations between age and MN frequency for women from both the boron-rich (r = 0.133, P = 0.48, P > 0.05) and boron-poor (r = -0.033, P = 0.861, P > 0.05) regions. The results suggest that ingestion of boron in the drinking water decreases the incidence of cervical cancer-related histopathological findings. There was no correlation between the pathological findings from the cervical smears and buccal cell MN frequency suggesting that the two study populations were exposed equally to gentotoxic agents. Nonetheless, cervical cancer-related histopathological findings should be validated by other researchers. (c) 2007 Wiley Periodicals, Inc.
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    In situ atom trapping of Bi on W-coated slotted quartz tube flame atomic absorption spectrometry and interference studies
    (Pergamon-Elsevier Science Ltd, 2013) Kilinc, Ersin; Bakirdere, Sezgin; Aydin, Firat; Ataman, O. Yavuz
    Analytical performances of metal coated slotted quartz tube flame atomic absorption spectrometry (SQT-FAAS) and slotted quartz tube in situ atom trapping flame atomic absorption spectrometry (SQT-AT-FAAS) systems were evaluated for determination of Bi. Non-volatile elements such as Mo, Zr, W and Ta were tried as coating materials. It was observed that W-coated SQT gave the best sensitivity for the determination of Bi for SQT-FAAS and SQT-AT-FMS. The parameters for W-coated SQT-FAAS and W-coated SQT-AT-FAAS were optimized. Sensitivity of FAAS for Bi was improved as 4.0 fold by W-coated SQT-FAAS while 613 fold enhancement in sensitivity was achieved by W-coated SQT-AT-FAAS using 5.0 min trapping with respect to conventional FAAS. MIBK was selected as organic solvent for the re-atomization of Bi from the trapping surface. Limit of detection values for W-coated SQT-FAAS and W-coated SQT-AT-FAAS was obtained as 0.14 mu g mL(-1) and 0.51 ng mL(-1), respectively. Linear calibration plot was obtained in the range of 2.5-25.0 ng mL(-1) for W-coated SQT-AT-FAAS. Accuracy of the W-coated SQT-AT-FAAS system was checked by analyzing a standard reference material, NIST 1643e. (C) 2013 Elsevier B.V. All rights reserved.
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    Sensitive determination of bismuth by flame atomic absorption spectrometry using atom trapping in a slotted quartz tube and revolatilization with organic solvent pulse
    (Pergamon-Elsevier Science Ltd, 2012) Kilinc, Ersin; Bakirdere, Sezgin; Aydin, Firat; Ataman, O. Yavuz
    Sensitivity of flame atomic absorption spectrometry (FAAS) for Bi determination was improved by slotted quartz tube (SQT) that was used also for atom trapping (AT). The trapped analyte was released by aspirating a small volume of organic solvent after a reasonable analyte collection time. Sensitivity was improved by 2.9 times by SQT-FAAS and 256 times by SQT-AT-FAAS with respect to FAAS. Optimum trapping period was found to be 6.0 min (36.0 mL of solution). Limit of detection (LOD) for SQT-AT-FAAS was found to be 1.6 ng mL(-1). %RSD was calculated as 4.0% for five replicate measurements of 7.5 ng mL(-1) Bi by SQT-AT-FAAS. Accuracy of the method developed was checked by analyzing a standard reference material of simulated fresh water (NIST 1643e) and result found was in good agreement with the certified one. The method can be applied in any laboratory equipped with a flame AA spectrometer. The consumption of time and sample volume is fairly low and application is simple and easy. (C) 2012 Elsevier B.V. All rights reserved.
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    Trace level determination of beryllium in natural and flavored mineral waters after pre-concentration using activated carbon
    (Taylor & Francis Ltd, 2011) Kilinc, Ersin; Bakirdere, Sezgin; Yaman, Mehmet
    The concentrations of beryllium (Be) in natural and flavored mineral water samples were determined by flame atomic absorption spectrophotometer (FAAS) after pre-concentration based on the complexation of Be(+2) with a mixture of acetylacetone (pentane-2,4-dione) plus morin (3,5,7,2',4'-pentaoxyflavone) and adsorption on activated carbon. The adsorbed complex was eluted with 1.5 ml of 2.0 M HNO(3) and evaporated to dryness. After adding 1.5 ml of 2 M HNO(3) and centrifuging, Be in acid solution was determined by FAAS. To remove a number of metals present in water, EDTA was used as a chelating agent. Beryllium in mineral water samples was pre-concentrated by 500-fold, taking 750 ml as initial sample and 1.5 ml as the final volume. The relative standard deviations were sufficiently low for practical purposes and recoveries were up to 85%. Spiking experiments were performed in real samples to establish accuracy and recoveries. The limits of detection and quantification were 0.01 and 0.03 ng ml(-1), respectively. Twenty samples were analyzed for their beryllium content using optimum parameters. The highest concentration of beryllium was found to be 0.94 +/- 0.15 ng ml(-1) in a natural mineral water, while beryllium was not detected in five samples.
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    Use of Sequential Extraction With UV/Vis Spectrophotometer to Assess Phosphorus Species in Surface Sediments (NE Mediterranean Sea)
    (Atomic Spectroscopy Press Ltd, 2010) Gunduz, Beniz; Aydin, Isil; Bakirdere, Sezgin; Saydut, Abdurrahrnan; Aydin, Firat
    The speciation of total phosphorus in different forms is necessary to understand the phosphate exchange mechanisms in sediments, its potential removal from the water column, and the availability of phosphorus for primary producers. This paper presents the phosphorus (P) distribution (total phosphorus, organic phosphorus, and forms of inorganic phosphorus; loosely adsorbed phosphorus and phosphorus bound to aluminium, phosphorus bound to calcium, and phosphorus bound to iron, as well as total inorganic phosphorus) in surface sediments collected from two coasts (each under different anthropogenic pressures) in the eastern Mediterranean Sea in April 2007. The sampling stations are located at on the south-eastern Mediterranean coast of Turkey, adjacent to the Cilician Basin. The most abundant phosphorus in studied surface sediments was found as calcium-bound phosphorus. Relative abundances of the remaining phosphorus forms follow the order: P-Al > loosely bound-P> P-Fe. The concentration of total phosphorus in the surface sediments taken from Tasucu was found to be higher than the sediments from Erdemli. Accuracy of the method was checked by using NCS DC 73316 certified reference material and the results found were found to be in good agreement with the certified value. Maximum values of total P in Erdemli and Tasucu were 220.35 and 321.42 mu g g(-1), respectively.