Speciation of selenium in vitamin tablets using spectrofluorometry following cloud point extraction

Güler N. | Maden M. | Bakirdere S. | Ataman O.Y. | Volkan M.

Article | 2011 | Food Chemistry129 ( 4 ) , pp.1793 - 1799

Selenium is one of the trace and essential elements for good health but required only in a very narrow range. Hence, determination of selenium in trace level is important. In this work, cloud point extraction (CPE) with non-ionic surfactant Triton X-114 and the fluorometric ligand, 2,3-diaminonaphtalene (DAN) were used for extraction of trace amounts of organic and inorganic selenium species prior to their determination by spectrofluorometry. CPE parameters affecting complexation and phase separation were optimised. The limit of detection calculated by using nine replicate measurements of 0.020 mg/L Se solution after complexing with . . . DAN and 10-fold CPE preconcentration was 2.1 µg/L. Accuracy of the method was checked using EnviroMat Waste Water, EU-L-2 as CRM and result was found to be in good agreement with the certified value. The suggested method can be used for selenium species of selenite, selenate, and total organic selenium at µg/L level. © 2011 Elsevier Ltd. All rights reserved Daha fazlası Daha az

Polyhydroxybutyrate-b-polyethyleneglycol block copolymer for the solid phase extraction of lead and copper in water, baby foods, tea and coffee samples

Wadhwa, Sham Kumar | Tüzen, Mustafa | Kazi, Tasneem Gul | Soylak, Mustafa | Hazer, Baki

Article | 2014 | Food Chemistry152 , pp.75 - 80

A new adsorbent, polyhydroxybutyrate-b-polyethyleneglycol, was used for the separation and preconcentration of copper(II) and lead(II) ions prior to their flame atomic absorption spectrometric detections. The influences of parameters such as pH, amount of adsorbent, flow rates and sample volumes were investigated. The polymer does not interact with alkaline, alkaline-earth metals and transition metals. The enrichment factor was 50. The detection limits were 0.32 µg L-1 and 1.82 µg L-1 for copper and lead, respectively. The recovery values were found >95%. The relative standard deviations were found to be less than 6%. The validat . . .ion of the procedure was performed by analysing certified reference materials; NIST SRM 1515 Apple leaves, IAEA-336 Lichen and GBW-07605 Tea. The method was successfully applied for the analysis of analytes in water and food samples. © 2013 Elsevier Ltd. All rights reserved Daha fazlası Daha az

Trace elements in Pleurotus sajor-caju cultivated on chemithermomechanical pulp for bio-bleaching

Sivrikaya H. | Bacak L. | Saraçbaş A. | Erolu H.

Article | 2002 | Food Chemistry79 ( 2 ) , pp.173 - 176

Some trace elements were analyzed in Pleurotus Sajor-caju mushroom cultivated on chemithermomechanical pulp. In this experiment, phytohormones, such as 2.4-D and PS A6, were studied at concentrations of 10, 20 and 30 mg/100 ml, mixed into the pulp. Determination of mineral elements was done by flame atomic absorption spectrophotometry (Perkin Elmer model 1100 B). Sixteen mineral elements were determined in all samples. Cu, Mg, Pb, Na, Ag, Bi, Mn, Ni, Li, Co, Sb, Ca, Zn, Fe, Cr and Al contents of mushrooms, grown on treated pulp, were near control values. K was not present. Copyright © 2002 Elsevier Science Ltd.

Solid phase extraction of lead, cadmium and zinc on biodegradable polyhydroxybutyrate diethanol amine (PHB-DEA) polymer and their determination in water and food samples

Tüzen, Mustafa | Şahiner, Samet | Hazer, Baki

Article | 2016 | Food Chemistry210 , pp.115 - 120

A new biodegradable polyhydroxybutyrate diethanol amine (PHB-DEA) polymer was used as adsorbent for the sensitive and selective separation, preconcentration and determination of Pb(II), Cd(II) and Zn(II) by using atomic absorption spectrometry. Diethyl dithiocarbamate was used as chelating reagent. Analytical parameters such as pH, eluent type and its volume, flow rates of sample solution, ligand amount, sample volume were optimized. Effects of some cations, anions and transition metal ions were also investigated. Enrichment factor and relative standard deviation were found to be 100 and 3%, respectively. The limits of detection bas . . .ed on three times standard deviation of blanks (N = 21) were found 1.05 µg L-1 for Pb(II), 0.42 µg L-1 for Cd(II) and 0.13 µg L-1 for Zn(II). Limits of quantification (10 s, N = 21) were found 3.47 µg L-1 for Pb(II), 1.39 µg L-1 for Cd(II) and 0.43 µg L-1 for Zn(II). Accuracy evaluation of the method was confirmed with analyses of certified reference materials (NIST SRM 1515 Apple leaves, IAEA 336 Lichen, GBW 07605 Tea). Optimized method was applied to tap water and food samples after microwave digestion method. Cadmium and lead values in some samples were found higher than legal limits. © 2016 Elsevier Ltd. All rights reserved Daha fazlası Daha az

A newly synthesized graft copolymer for magnetic solid phase microextraction of total selenium and its electrothermal atomic absorption spectrometric determination in food and water samples

Açıkkapı, Ayşe Nihan | Tüzen, Mustafa | Hazer, Baki

Article | 2019 | Food Chemistry284 , pp.1 - 7

A newly synthesized polystyrene-g-polyoleic acid-g-polyethylene glycol graft copolymer (PoleS-PEG) was used as adsorbent in the solid phase microextraction of selenium ions by using electrothermal atomic absorption spectrometry (ETAAS). Neodymium magnet was used for separation of analyte ions. Various analytical parameters such as pH, adsorbent amount, mixing time, eluent solution, sample volume, etc. were optimized. The matrix effects of some cations and anions were also studied. The capacity of the adsorbent was found 11.5 mg g -1 . The preconcentration factor was found to be 50. The detection limit (LOD) and quantification limit . . .(LOQ) were found 6.06 ng L -1 and 20 ng L -1 , respectively. The calibration curve was linear in the range of 0.02–4.0 µg L -1 . Relative standard deviation was found 3.2%. The accuracy of the method was provided by using standard reference materials. The optimized method was successfully applied to natural water and food samples. © 2019 Elsevier Lt Daha fazlası Daha az

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