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    Basic nutrients and element contents of white cheese of diyarbakir in turkey
    (Elsevier Sci Ltd, 2004) Merdivan, M; Yilmaz, E; Hamamci, C; Aygun, RS
    Basic nutrients, moisture, fat and protein, and concentrations of 15 major and trace elements in total and fatty parts of Diyarbakir white cheese were evaluated for compositional differences. Elements were determined using inductively coupled plasma atomic emission spectrometry, while fat was determined by supercritical extraction and protein by protein/nitrogen analyzer. Diyarbakir brine and melt cheeses have lower humidity and higher protein than market brine cheese samples. The fat level was 14-18% for all cheeses. The levels of investigated major and trace elements were much higher in three types of cheese samples. Except for Zn and Mn, the other investigated elements were found in fairly low concentrations and at variable ranges in the fatty part of cheese samples. The elements, Mg among major elements and Fe among trace elements, were highest in that part. Na and Ca as major and Zn, Fe and Al as trace elements were found at maximum levels, especially in Diyarbakir melt cheese. Also, levels correlations between basic nutrients, basic nutrients and elements and element pairs were investigated. (C) 2003 Published by Elsevier Ltd.
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    Chemical analysis of geothermal water of Cermik, Turkey
    (Parlar Scientific Publications (P S P), 2003) Akba, O; Baysal, A; Hamamci, C; Merdivan, M; Gumgum, B
    Geothermal water of Cermik, which is located in Southeast Anatolia - Turkey, is a Na-Cl-HCO3 type containing also sulfide and iodide. The temperature, pH and flow rate of the geothermal water are 51 degreesC, 7.6 and 21 L s(-1), respectively. Its physical and chemical characterization in detail was done using standard methods. The trace elements Al, Ba, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr and Zn were analyzed directly using inductively coupled plasma-atomic emission spectrometry due to very low detection limits and the good reproducibility of this analytical method.
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    Chiral separation of amino acids by chiral octamide derivatives of calixarenes derived from resorcinol by impregnation on a polymeric support
    (Pergamon-Elsevier Science Ltd, 2005) Seyhan, S; Özbayrak, Ö; Demirel, N; Merdivan, M; Pirinccioglu, N
    Chiral amide derivatives of octaester calixresorcarene were synthesized and employed as chiral stationary phases for chiral discrimination of amino acid derivatives. Enantiomers of phenylglycine and tryptophan were easily discriminated as their sodium and potassium salts. In addition, phenylalanine-trytophan, phenylglycine-trytophan mixtures were separated by column chromatography. (c) 2005 Elsevier Ltd. All rights reserved.
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    Comparison of microwave digestion procedures for the determination of some elements in asphaltite ash using ICP-AES
    (Soc Chimica Italiana, 2002) Baysal, A; Akba, O; Merdivan, M; Hamamci, C; Gümgüm, B
    A microwave digestion procedure for asphaltite ash was developed in an attempt to facilitate routine analysis and obtain reproducible conditions or comparable results. The. conditions of the most effective procedure for 0.1g asphaltite ash samples are 1 ml of HNO3 + 3 ml of HCl + 1 ml of HF + 1 ml of deionized water as acid mixture and 15 min for digestion time. The digestion was accomplished in five stages applying continuously 90 % to 20 % of the microwave power and 20 to 100 psi of the pressure for 10 min of total time. Concentrations of selected elements, Cr, Co, Fe, Mn, Ni and Zn were measured using inductively coupled plasma-atomic emission spectroscopy. The proposed method of digestion provided precise results with relative standard deviations generally less than 3 % for investigated elements. Results for fly ash as standard reference material was in good agreement with certified values.
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    Concentrations of trace elements in wild edible mushrooms
    (Elsevier Sci Ltd, 2001) Isiloglu, M; Yilmaz, F; Merdivan, M
    The concentrations of Cu, Cd, Co, Ni, Mn, Pb, Zn and Fe in 66 samples of mushroom fruiting bodies, representing seven species, mainly all edible, were determined by atomic absorption spectrophotometry. The mushrooms were collected from near roads and inner parts of forest and lawns in Bahkesir in the north western part of Turkey. The results indicate that the Fe level in the species Volvariella speciosa (Fr.) Sing. from near the road was the highest with a mean of 6990 mg/kg. The level of Ni was the highest in Clitocybe flaccida (Sow.: Fr.) Kummer, from near road with a mean of 3.32 mg/kg. Cu levels were almost similar for both areas within a range of 35-89 mg/kg in the different species. The Cd was accumulated mostly by Lactarius sanguifluus (Paulet: Fr.) Pr. and V. speciosa from near road with a mean of 1.60 mg/kg. Concentration of Mn, Pb, Co and Zn in L. sanguifluus from near road were the highest with means of 63.6, 7.66, 6.03 and 149 mg/kg, respectively. (C) 2001 Published by Elsevier Science Ltd.
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    Elemental composition of Southeastern Anatolia asphaltites (Turkey) as a function of particle size
    (Estonian Academy Publishers, 2003) Hamamci, C; Düz, MZ; Saydut, A; Merdivan, M
    Elemental composition of asphaltites from Southeastern Anatolia was determined after grinding the samples and separating particles obtained into fractions by sieving. The total content of carbon, hydrogen, nitrogen and sulfur was highest in Halbur asphaltite where they were present over a wide size range (from 125 to 600 mum). The content of nitrogen, the least element in asphaltites, did not depend on grain size, whereas the carbon and sulfur concentrations increased with increasing size.
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    Extraction of some transition metals with N,N-dibutyl-N?-benzoylthiourea into molten paraffin at 65°C
    (Elsevier, 2000) Merdivan, M; Güngör, A; Savasci, S; Aygün, RS
    The solid-liquid extraction behaviour of some transition metals (Cu(II), Co(II), Ni(II), Cd(II) and Pb(II)) by the use of N,N-dibutyl-N'-benzoylthiourea as an extractant in paraffin (58-60 degrees C) has been investigated at 65.0 +/- 0.5 degrees C. The effect of equilibration time, pH of the aqueous phase, concentration of extractant and solid solvent used on the extraction efficiency of these metals have been discussed. The interferences of various ions are examined. The method has been applied to the determination of these metals in synthetic samples, mushrooms and sediment. (C) 2000 Elsevier Science B.V. All rights reserved.
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    Formation and characterization of humic acids from low rank anatolian coals by air oxidation
    (Taylor & Francis Inc, 2005) Erdogan, S; Duz, MZ; Merdivan, M; Hamamci, C
    The results of this study are aimed at evaluating the effects of air oxidation time, temperature and demineralization on humic acid production from two low-rank Anatolian coals. Two Anatolian low rank coals were studied at 120 and 200degreesC up to 10 days with and without demineralization. The best results for humic acid formation were obtained at a high temperature for longer times. Demineralization effect is negligible for studied coals. The rate of humic acid formation increased at first with increase in oxidation time, reached a maximum, and then decreased at high oxidation time. Also, a detailed study of the elemental composition, the characterization by FTIR, and the acidity of humic acids are reported.
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    Heavy metal contents in some macrofungi collected in the northwestern part of Turkey
    (Springer-Verlag, 2001) Isiloglu, M; Merdivan, M; Yilmaz, F
    Eight metal contents were determined in wild growing macrofungi collected from two different areas in Balikesir and Akhisar (NW Turkey). The analysis has been done by atomic absorption spectrophotometry in 179 samples of 16 species. Pb was accumulated extensively by G. sessile and L. cinerascens in both areas. Concentration of Cd was significantly high in A, pseudopratensis from background area and M. excissa from near road area. The high concentrations of Fe and Zn were found in M, ramealis and L, cinerascens for both areas. The mean concentration of Cu was high in V. pratense from background area and C. butyracea var. butyracea from near road area. The highest mean concentrations of Co and Mn for both areas were seen in G. sessile and M. excissa, respectively. A high Ni concentration was found in G. sessile and H. hypothejus from background area. We found no considerably significant differences in the concentrations of all studied elements between two areas.
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    Heroin profiling using alkaloids and metal concentrations
    (Elsevier Sci Ireland Ltd, 2003) Bora, T; Merdivan, M; Hamamci, C
    [Abstract Not Available]
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    Levels of trace and major elements in illicit heroin
    (Amer Soc Testing Materials, 2002) Bora, T; Merdivan, M; Hamamci, C
    Ten elements, aluminum (Al), barium (Ba), calcium (Ca), cadmium (Cd), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), lead (Pb), and zinc (Zn) were analyzed in 44 illicit heroin samples from Southeast Anatolia, Turkey. Illicit heroin samples were dissolved in nitric acid using microwave oven and were quantified by electrothermal atomic absorption spectrometry (Cd and Pb) and inductively coupled plasma-atomic emission spectrometry (Al, Ba, Ca, Cu, Fe, Mg, Mn, and Zn). The most abundant element was calcium, 4050 to 14200 mug/g, which could be ascribed to the use of lime in the manufacturing process and/or as diluting agent. Iron (180 to 1470 mug/g), aluminum (42 to 2280 mug/g), and zinc (160 to 210 mug/g) were found at moderately high levels, possibly because of the use of metal pots in the acetic anhydride cooking process and also for storage. Cadmium and lead concentrations were at the lowest measured levels. The amounts of magnesium, manganese, barium, and copper were in the range of 100 to 800 mug/g, 3 to 17 mug/g, 4 to 30 mug/g, and 2 to 46 mug/g, respectively.
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    Matrix effects of concomitant species on the determination of nickel by inductively coupled plasma atomic emission spectrometry
    (Mrs Pushpa Agarwal, 2005) Akba, O; Baysal, A; Merdivan, M; Hamamci, C; Gumgum, B
    The interference on the determination of nickel by the salts LiCl, NaCl, KCl, CsCl, NH4Cl, Na2SO4, NaNO3, NaC2H3O2 in an inductively coupled plasma-atomic emission spectrometry has been carried out. The salt concentration was in the 100-10000 mg L-1 range. Nickel emission was enhanced at lower matrix concentrations (100 mg L-1) and was depressed at higher matrix concentrations (10000 mg L-1). Except cesium, above 100 mg L-1, all studied ions caused a decrease in the signal intensity in the range of 0-15%. The sequence order of the investigated ions for the enhancement and depression was unstable. The sequence order in enhancement was found as Li+ < Na+ < K+ < Cs+ < NH4+ for cation; NO3- < SO42- < Cl- < OAc- for anions and Cs+ < NH4+ < K+ < Li+ < Na+ for cat-ions and OAc- < SO42- Cl- < NO3- for anions in depression at the studied lines.
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    N,N-diethyl-N?-benzoylthiourea -: A new spectrophotometric reagent for rhenium determination
    (Soc Chimica Italiana, 2001) Merdivan, M; Aygun, RS
    The reagent N,N-diethyl-N'-benzoylthiourea produces a green complex with rhenium in hydrochloric acid medium in the presence of tin(II) chloride. The complex extracted into toluene shows an absorption maximum at 383 nm, obeys Beer's law from 1.5 to 22 mug ml(-1) of rhenium while its molar absorptivity and Sandell sensitivity are 6.66 x 10(3) L mol(-1) cm(-1) and 0.028 mug cm(-2), respectively. It tolerates the presence of a large number of ions, including Mo(VI), W (VI) and some platinum metals. Job's and the mote ratio methods indicate that the rhenium metal and the chelating agent ratio of 1:2 in solution. The system has been applied to the determination of rhenium on synthetic samples and alumina based catalysts.
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    Polymer supported humic acid for separation and preconcentration of thorium(IV)
    (Taylor & Francis Inc, 2004) Erdogan, S; Merdivan, M; Hamamci, C; Akba, O; Baysal, A
    The resin impregnating humic acid (HA) onto XAD-4 has been prepared to investigate adsorption behaviour of Th(IV). The characterization of the resulting resin has been carried out by infrared spectral data and sorption capacity. Maximum adsorption capacity of Th(IV) on the resin is found to be 1.51 X 10(-4) mol g(-1) at pH 4. The sorbent was found to possess a high selectivity for Th(IV) with an optimum extraction pH around 3-7. Recoveries for Th(IV) determined prior to breakthrough were found to be quantitative (96-99%). The resin exhibits good chemical stability, reuseability, and a faster rate of equilibration for Th(IV) determination. The influence of several ions as interferents is discussed. The method has been successfully applied for the separation of Th(IV) in synthetic mixtures.
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    Solvent extraction of platinum group metals with N,N-diethyl-N?-benzoylthiourea
    (Soc Chimica Italiana, 2000) Merdivan, M; Aygün, RS; Külcü, N
    [Abstract Not Available]
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    Sorption behaviour of uranium(VI) with N,N-dibutyl-N?-benzoylthiourea Impregnated in Amberlite XAD-16
    (Elsevier Science Bv, 2001) Merdivan, M; Düz, MZ; Hamamci, C
    The sorption of U(VI) by N, N-dibutyl, N'-benzoylthiourea (DBBT) impregnated resin has been studied. DBBT impregnated resin was prepared by direct adsorption of chelating ligand onto macroporous support, Amberlite XAD-16. The adsorption of DBBT on the macroporous support is shown by FTIR spectroscopy to be the result of only weak chelating ligand-support interactions. Parameters such as the pH effect on the sorption of uranium, the sorption capacity of the impregnated resin, the stripping of uranium and the effect of coexisting ions were investigated by batch experiments. The results demonstrated that uranium(VI) ions, at pH 4.5-7 could be sorbed completely using 0.1 g Amberlite XAD-16 resin loaded with DBBT. The sorption capacity of the impregnated resin is 0.90 mmol uranium(VI) g(-1). Quantitative recovery of U(VI) is achieved by stripping with 0.1 M HNO3. The method was applied to the determination of uranium in synthetic samples. The precision of the method was 2.4 RSD% in a concentration of 1.20 mug ml(-1) for ten replicate analysis. (C) 2001 Elsevier Science B.V. All rights reserved.
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    Thorium(IV) and uranium(VI) sorption studies on octacarboxymethyl-C-methylcalix[4]resorcinarene impregnated on a polymeric support
    (Elsevier, 2003) Demirel, N; Merdivan, M; Pirinccioglu, N; Hamamci, C
    The impregnation of octacarboxymethyl-C-methylcalix[4]resorcinarene into a polymeric matrix, Amberlite XAD-4, is reported and was characterized by infrared spectroscopy. The sorption capacity of the impregnated resin is 0.34 x 10(-3) mol g(-1). The resin was used for the sorption of thorium(IV) and uranium(VI) from aqueous solution. The properties of capacity, pH effect, and breakthrough curves of the impregnated resin were investigated. The capacity of the resin for Th(IV) and U(VI) was found to be 0.29 and 0.27 x 10(-3) mol g(-1), respectively. The metal ions were eluted with 0.4-2 M HCl or HNO3. Chromatographic separation of Th(W) and U(VI) was accomplished by adjustment of pH to 3.0 and 6.0, respectively. The impregnated resin exhibits a high chemical stability, reusability and fast equilibration. Separation of Th(W) and U(VI) from other metal cations in synthetic solution was achieved. (C) 2003 Elsevier Science B.V. All rights reserved.