1,720,988 research outputs found
Speciation and determination of inorganic selenium species in certain fish and food samples by gold-coated W-coil atom trap hydride generation atomic absorption spectrometry
No full textA very sensitive, selective, rapid and easy gas-phase preconcentration based method is presented for the determination and speciation of inorganic selenium in chicken meat, poultry eggs, mullet fish (Mugil Cephalus) and sea bass fish (Dicentrarchus Labrax) samples. Gold-coated W-coil atom trap was used to increase the sensitivity of conventional HG-AAS. LOD and LOQ values were calculated to be 0.021 μg/L and 0.070 μg/L, respectively. RSD% was found as 3.24. The sensitivity was increased 20 times more with the method used in the current study than the HG-AAS method. The interference effects of other metals on Se signal were significantly reduced by trap. SEM and EDX images of both bare and gold coated W-coil atom trap were screened. In order to check the accuracy of the method, "DOLT-5: Dogfish Liver" standard reference material was used and there was a good agreement between certified and found values at the 95% confidence level
A Study of Trace Element Contents in Plants Growing at Honaz Dagi-Denizli, Turkey
No full textWOS: 000268985500001Denizli is one of the rapidly developing states in the West Anatolian Region of Turkey Keeping this in view, 30 different plants were selected to study their potential as biomonitors of trace elements like Pb, Cd, Ni, Zn, Fe and Mn (mu g g(-1), dry weight). The samples were collected from two different altitudes of Honaz Dagi, a mauntain overlooking at state of Denizli. The concentrations of trace elements were determined by flame atomic absorption spectrometry (FAAS). The mean concentrations determined at 1000 in altitude ranged between 0.273 to 0.488, 0.099 to 0.488, 0.306 to 0.682, 1.017 to 3.744, and 0.148 to 0.674 (mu g g(-1), dry weight), of Pb, Ni, Zn, Fe and Mn, respectively. At 1600 in altitude, the values ranged between 0.225 to 0.534, 0.150 to 0.842, 0.234 to 0.905, 1.082 to 3.864 and 0.023 to 0.982 (mu g g(-1), dry weight) of Pb, Ni, Zn, Fe, Pb and Mn, respectively. No Cd was detected at both altitudes
The color removal and photocatalytic degradation of olive mill waste water by using /Sep. nanoparticle
No full textBu çaışmada, Sepiyolit minerali ve bir arada kullanılarak, /Sep. nanokompozit materyali elde edildi. Daha sonra, bu materyal kullanılarak UV ve 'li ortamda zeytin karasuyu gibi organik yükü yüksek atık suyun fotokatalitik yöntemle arıtılabilirliği araştırıldı. Çözelti pH'sı, katalizör oranı, zaman ve sıcakık gibi parametrelerin renk değişimi üzerine etkisi incelendi. Çaışma sonucunda, pH= 5,0, 298K, 0,5 g/L katalizör oranı ve 10 saat sonunda maksimum oranda renk giderimi gerçekleşti (%95-99). Ayrıca, hazırlanan /Sep. materyallere ait XRD, SEM-EDX ve BET yüzey alanları gibi karakterizasyon çaışmaları yapıldı. Endüstriyel atık suların arıtımında maliyetinde önemli bir yer tuttuğu dikkate aınarak, maliyet analizi yapıldı. Bu çaışma sonucunda, birçok arıtım işlemlerinden daha düşük maliyet oluşturabileceği ve bazı ön arıtımlar yapıldıktan sonra maliyetin çok daha düşük oranda gerçekleşebileceği görüldü.In this study, /Sep. nanocomposite material has been produced from sepiolite and . Then, the photocatalytic degradation of olive mill waste water (OMW) has been investigated by using /Sepiolite nanoparticle with UV and medium. The effect of parameters such as /Sep. dose, solution pH, temperature and reaction times on the color removal of the olive mill waste water was also investigated. At the end of the study, high color removal was observed for pH= 5.0, 298K, 0.5 g/L of /Sep. dose and 10h (%95-99). In addition, these materials were characterized by scanning electron microscopy (SEM) with energy dispersive X-ray microanalyses (EDX) and Brunauer-Emmett-Teller (BET) surface area measurements. Moreover, cost analysis has been done for this method and it has been seen that the proposed method is inexpensive if it's compared with other purification systems, with some pretreatments cost gets lower. As a result, the photocatalytic process by using UV///Sep.nanoparticle can be considered as a suitable purification method for olive mill waste water and other wastewaters that include organic pollutants
A road map to assess critical materials content in boron industrial wastes using sustainable micro-X-ray fluorescence and total reflection X-ray fluorescence instrumentation
No full textWOS: 000582495800002Turkey is the leading country in the world in terms of boron production and sale. Increasing boron production goes along with an increasing generation of boron wastes. The pollution of the soil and the air around the waste piles, as well as the occupation of several square kilometers of ground, are major environmental problems. It is, therefore, very important to snake use of the wastes to both protect the environment and create revenue. This work presenteda road map for fast screening of boron waste for critical elements followed by determination of the elements using small footprint low power instrumentation. The sample preparation was kept to a minimum. A procedure that allowed an assessment of critical materials in industrial production waste with minimal consumption of hazardous acids, energy, and time was presented. The samples were first screened for valuable and hazardous elements by micro- X-ray fluorescence (XRF). Samples with considerable contents of Cs, Rb, and Aswere then prepared as slurries for the total reflection XRF (TXRF) measurement. To evaluate the TXRI: procedure, a standard reference material was analyzed. As a result, Rb and Cs in concentrations up to 420 +/- 70 and 1500 +/- 200 mg/kg were detected in some of the waste forms. The time savings were in order of a factor of 3 when comparing the prescreening combined micro-XRF and TXRI: approach to an all TXRPanalysis approach.Washington State University (WSU); Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK)The authors thank Washington State University (WSU) for funding part of this research and part of the research stay of Ibrahim Kula at WSU. Ibrahim Kula thanks the Scientific and Technological Research Council of Turkey (TUBITAK) for funding the research stay at WSU
Preparation, characterization, and adsorption studies of coreAshell SiO2-CeO2 nanoparticles: a new candidate to remove Hg(II) from aqueous solutions
No full textWOS: 000384977600003SiO2 supported core@shell nanoparticles (CSNs) have recently attracted great attention due to their unique, tunable, optical, photocatalytic, and higher adsorption properties. In this study, SiO2@CeO2 CSNs were synthesized using a chemical precipitation technique and characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM) analysis. XRD analysis showed that SiO2 particles were the core while CeO2 particles were the shell. It was seen as a new band at 961 cm(-1) of the oxygen bridge between Si and Ce atoms from FT-IR results; SiO2 and CSNs were spherical (0.5-0.6 mu m) from SEM and TEM analyses. Different parameters such as contact time, initial concentration, pH, and temperature were investigated. The optimum conditions for temperature, pH, and contact time were 25 degrees C, 8.0, and 60 min, respectively. In addition, the equilibrium adsorption data were interpreted using Langmuir and Freundlich models to describe the uptake of Hg(II). The Freundlich isotherm model (R-2: 0.99) fit better than Langmuir and the q(max) value was 153.8 mu g g(-1) at various concentrations (0.1-1 mg L-1). The thermodynamic parameters were also calculated and, from these results, it can be shown that our synthesized particles can be used in water purification systems to remove Hg(II)
Determination and speciation of selenium in water samples collected from Mugla (Turkey) province by hydride generation atomic absorption spectrometry
No full textIn this work, determination of selenium in various water samples was done by using hydride generation atomic absorption spectrometry. The most appropriate values of HCl concentration, NaBH4 concentration, NaOH concentration, flow rate of argon and flow rate of waste solution were determined. The optimum concentration of the HCl, NaBH4 and NaOH solutions were found to be 7.0 mol L-1, 1.0% and 0.75%, respectively. The optimum flow rate of Ar gas and waste solution were also found to be 100.9 mL min(-1) and 4.0 mL min(-1), respectively. Values of LOD and LOQ were calculated separately for total Se and Se(IV). LOD and LOQ values were calculated 0.56 mu g L-1, 1.87 mu g L-1 for total Se and 0.72 mu g L-1, 2.40 mu g L-1 for Se(IV), respectively. The precision was evaluated by relative standard deviation (RSD%) was found to be 3.5% for total Se and 3.1% for Se(IV) (n = 11). A standard reference material (NIST 1643e) was used in order to check the accuracy of the proposed method. There was a good agreement between certified and found values for standard reference material. The method was applied to the analysis of total Se and Se(IV) concentrations in tap water samples collected from the various regions of Mugla. Proposed method showed spike recovery ranges from 92% to 116% in water samples
Development of a Sensitive Method for Cadmium Determination in Fish Tissue and Drinking Water Samples by FAAS Using SQT In Situ Atom Trapping
No full textA sensitive and robust trap method was developed for the determination of cadmium (Cd) by using a slotted quartz tube. Using this method at a sample suction rate of 7.4 mL/min for 4.0 min collection, a 1467-fold increase in sensitivity was obtained compared to the flame atomic absorption spectrometry method. Under the optimized conditions, a limit of detection of 0.075 ng mL-1 was obtained for the trap method. The interference effects of hydride-forming elements, transition metals, and some anions on the Cd signal were investigated. The developed method was evaluated by analyzing "Sewage Sludge-industrial origin (BCR no: 146R)", "NIST SRM 1640a Trace elements in natural water", and "DOLT: 5 Dogfish Liver". There was a good agreement between the certified and found values at the 95% confidence level. This method was applied successfully for the determination of Cd in drinking water and some fish tissue samples (liver, muscle, and gill) obtained from Muğla province
Determination and speciation of methyl mercury and total mercury in fish tissue samples by gold-coated W-coil atom trap cold vapor atomic absorption spectrometry
No full textA sensitive analytical technique was developed where gaseous mercury formed by sodium tetrahydroborate reduction is transported to and trapped on a resistively heated gold-coated Tungsten-coil atom trap for in situ preconcentration. This technique was applied successfully for determination and speciation of methyl mercury and total mercury in some fish tissue samples (liver, muscle and gill) obtained from Muğla province. The analytical parameters were optimized both for trap and no-trap studies. Under the optimized conditions, a limit of detection (LOD) of 6.0 ng/L was obtained. The precision was evaluated by relative standard deviation (RSD%) corresponding to 4.1% (n = 11). Accuracy of the proposed method was evaluated by analyzing “DOLT:5 Dogfish Liver”, “NIST SRM 1640a Trace elements in natural water” and “NIST 1946 Lake Superior fish tissues”. The measurements of the certified reference materials were in good agreement with the certified values at the 95% confidence level
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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