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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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    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.