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    A simple flow injection spectrophotometric procedure for direct determination of copper(II) in environmental samples
    (Chemical Publishing Co., 2014) Akmeşe, Bediha; Aydın, Rukiye; Asan, Adem
    A new simple, rapid and sensitive flow-injection spectrophotometric detection method has been developed for the on-line determination of copper(II) in environmental water samples. The method is based on the measurement of the absorbance of the coloured complex formed by copper(II) with the Alizarin Red S (3,4-dihydroxy-9,10-dioxo-2-anthracenesulfonic acid sodium salt) in an acidic medium. The optimum conditions for the reaction of Cu(II) with Alizarin Red S is studied and the complex is selectively monitored at ?max 510 nm. With the reagent carrier solvent (3.5 × 10-5 M Alizarin Red S solution and 0.1 M acetate buffer, pH 5.0) flow-rate of 1 mL min-1. The calibration graph was linear in the Cu(II) concentration range 2-110 ?g L-1 with the detection limit of 0.6 ?g L-1 (RSD = 3.3 %, n = 6) was obtained at a sampling rate of 80 sample h-1. The detailed study of various interferences confirmed the high selectivity of the developed method. The proposed method was successfully applied to determination of copper(II) in real samples including river water and sea water. The accuracy of the method was demonstrated by the analysis of standard reference material MBH-C31XB20.
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    Development of a flow-injection with spectrophotometric method for total iron in water samples
    (Hacettepe University, 2017) Asan, Adem; Akmeşe, Bediha
    Asimple spectrophotometric flow-injection method is reported for the highly sensitive and fast determination of iron(III) and total iron. The method is based on the formation of iron(III)- (1-nitroso-2-naphthol-3,6 sulphonate) (NRS) complex. The optimum conditions for the reaction of iron(III) with NRS is studied. And the complex is selectively monitored at ?max370 nm. With the reagent carrier solvent used was 5x10-4 M 1-nitroso2-naphthol-3,6 sulphonate in 0.1 M acetic acid-acetate buffer solution at pH 4.0. Parameters affect simultaneously for the determination of iron(III) and interfering ions were tested. Relative standard deviation for five consecutive injections of 70 µg.L-1 iron(III) was 1.46% and for 5 µg.L-1 iron(III), it was 3.12%. The calibration graph was linear in the iron(III) concentration range 0.1-100 µg.L-1 and the limit of detection was 0.05 µg.L-1 for a 20 µL injection volume. The precision and accuracy of the method were checked by analysis of certified reference material and AAS method. The method was successfully applied to determine trace amounts of iron(III) and total iron in river and sea water samples.
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    Optimization of the schiff-base reaction of acetylacetone with biogenic amines
    (Hitit University, 2017) Akmeşe, Bediha; Asan, Adem
    In this work, optimum conditions for the derivatization reaction of biogenic amines (histamine, tyramine, putrecine, tryptamine, phenylethylamine, cadaverine, spermidine and spermine) with acetylacetone have been determined. In this reaction, the amount of K2HPO4, reaction time, reagent amount, solvent choice and solvent amount were optimized. As a result of this study, optimum conditions were determined as amount of K2HPO4 2 g, reaction time 20 min, amount of acetylacetone 1 mL, solvent methanol and amount of solvent 10 mL.
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    Simultaneous determination of three phenolic compounds in water samples by pre-column derivatization coupled with reversed-phase high performance liquid chromatography
    (Hacettepe University, 2018) Asan, Adem; Konanç, M. Umut; Akmeşe, Bediha
    In this study, a sensitive and accurate method for simultaneous separation and determination of three phenolic compounds (phenol, m-cresol and resorcinol) in water by revesed-phase high performance liquid chromatography using uv-visible detection has been described. Pre-column derivatization with 4-aminoantipyrine is used for the seperation and determination phenol, m-cresol and resorcinol in water. The derivatives formed within 5 min were extracted with chloroform and then analyzed by liquid chromatography with UV-visible detection at 440 nm. Chromatographic separation was performed using a reversed-phase column and acetonitrile-water (45:55%, v/v) as the mobile phase. The three derivatives were elueted in 13 min. The detection limits of phenol, m-cresol and resorcinol in a standard water sample were between 0.07 and 0.09 ?g.L-1 for 100 mL respectively. The recoveries of the derivatives from pure water were betweeen 97.1-102.3% within relative standard deviations of 2.3-4.7%. The method was applied to the analysis of phenols in different water samples.