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Coliform bacteria immobilized on titanium dioxide nanoparticles as a biosorbent for trace lead preconcentration followed by atomic absorption spectrometric determination
(Springer Wien, 2011) Bakircioglu, Dilek; Ucar, Gokhan; Kurtulus, Yasemin Bakircioglu
Coliform bacteria physically immobilized on titanium dioxide nanoparticles can be used as a biosorbent for solid phase extraction of lead (II) ions from aqueous solution using a flow injection system coupled to flame atomic absorption spectrometry (FAAS). Effects of pH value, sample volume, flow rates of loading and elution, and the type and volume of eluent were investigated. Lead ions were sorbed on a biosorbent mini-column at pH 6.0, eluted with 1 mol L-1 HCl and then determined by FAAS. The limit of detection for the water samples is in order of 0.90 mu g L-1. The accuracy of the method was confirmed by analyzing a certified reference material (GBW 07605; tea). The results are in good agreement with the certified value. The precision of the method was also satisfactory. The procedure was applied to the evaluation of lead ions in river water, wine, and baby food.
Comparison of extraction induced by emulsion breaking, ultrasonic extraction and wet digestion procedures for determination of metals in edible oil samples in Turkey using ICP-OES
(Elsevier Sci Ltd, 2013) Bakircioglu, Dilek; Kurtulus, Yasemin Bakircioglu; Yurtsever, Selcuk
The content of elements (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in edible oils (sunflower, hazelnut, canola, corn and olive oils) from Turkey was determined using inductively coupled plasma optical emission spectrometry (ICP-OES) after ultrasonic extraction, wet digestion, and extraction induced by emulsion breaking procedures (EIEB). In order to evaluate the best sample preparation procedure, EIEB procedure was compared by ultrasonic extraction and wet digestion procedures. The results in the samples (minimum-maximum in mg kg(-1)) were : 0.022-0.058, Cr 0.126-7.106, Cu 0.570-4.504, Fe 8.004-12.588, Mn 0.035-0.054, Ni 0.908-2.182, Pb 0.099-0.134 and Zn 2.206-8.982. The EIEB procedure was found to be fast, reliable, simple, and excellent in comparison with the other studied procedures. The recovery test was performed by spiking the samples with known amounts of the metals in the form of organometallic standards and applying the EIEB procedure. The recoveries were in the range of 96-109%. (C) 2012 Elsevier Ltd. All rights reserved.
Comparison of Extraction Procedures for Assessing Soil Metal Bioavailability of to Wheat Grains
(Wiley, 2011) Bakircioglu, Dilek; Kurtulus, Yasemin Bakircioglu; Ibar, Hilmi
Agricultural soils have been analyzed to elucidate whether the trace metal distribution changes in relation to agricultural activities and to predict environmental risk. In addition to the extractability of Cu, Mn, Ni, Pb, and Zn in soils was compared by single extraction (hydrochloric acid (HCl), ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), calcium chloride (CaCl2), water (H2O)), and sequential extraction procedures. The modified Community Bureau of Reference (BCR) sequential extraction procedure (three-step) used to extraction of metals in soil samples. The extraction capacity of the analyzed metals was found by using single extraction procedures in the order: HCl > EDTA > DTPA > CaCl2 > H2O. A single correlation analysis was used to investigate the relationship between extractable metal concentrations in soil solutions and metal accumulation in wheat grains. Simple correlation analyses indicated that the extractable Pb and Ni of soils by HCl, EDTA, and DTPA single extraction procedures were significantly correlated with the metal contents of wheat grains. For CaCl2, H2O, and BCR extraction procedures there was a relatively poor correlation between the extractable Cu, Mn, Ni, Pb, and Zn of soils and metal contents of wheat grains.
Deep eutectic solvent-based three-liquid-phase-extraction system for one-step separation of Cu, Mg and Zn in water samples
(Academic Press Inc Elsevier Science, 2022) Kurtulus, Yasemin Bakircioglu; Bakircioglu, Dilek; Topraksever, Nukte
A novel and environmentally friendly three-liquid-phase extraction (TLPE) approach was developed for simultaneous separation of copper (Cu), magnesium (Mg) and zinc (Zn) from water samples. The proposed organic/ two aqueous phase system consists of di(2-ethylhexyl)phosphoric acid (D2EHPA), Choline Chloride:urea (deep eutectic solvent (DES)), and salt (K2HPO4). The effects of various factors including amount of DES and K2HPO4, pH, D2EHPA concentration, phase-mixing time, and diluent on the preconcentration/separation of Cu, Mg and Zn were evaluated. The results showed that 96.6% of Zn was concentrated in the D2EHPA-rich top phase, whereas 97.8% of Cu and 98.1% of Mg were quantitatively extracted into the DES-rich middle phase and salt-rich bottom phase, respectively. Excellent recovery (>97%) of Cu, Mg and Zn was obtained by using 20% (v/v) D2EHPA in hexane, and 1.72 g DES and 3.12 g K2HPO4 in two lower aqueous phases at pH= 4. The limits of detection were 1.58, 1.55 and 2.37 mg/L for Cu, Mg and Zn, respectively. Relative standard deviations (RSDs) for 0.5 mg/L and 1.0 mg/L of Cu, Mg and Zn in water samples were < 6%. The accuracy of the procedure was confirmed by analyzing a certified reference material of water and tea (NIST SRM 1640a, GBW 07605). Under optimized conditions, excellent agreement was observed between the TLPE-flame atomic absorption spectrometry (FAAS) results and certified values using the student's t-test (P = 0.05). TLPE procedure was successfully applied for the determination of Cu, Mg and Zn in water samples.
Determination of Several Element Levels in Hardaliye Beverages Using Flame Atomic Absorption Spectrometry After Ultrasound-Probe Extraction
(Aoac Int, 2017) Bakircioglu, Dilek; Topraksever, Nukte; Kurtulus, Yasemin Bakircioglu
In the present study, concentrations of calcium (Ca), copper (Cu), magnesium (Mg), manganese (Mn), sodium (Na), and zinc (Zn) in hardaliye samples produced in Turkey were determined by flame atomic absorption spectrometry after ultrasound probe extraction (UPE), microwave-assisted extraction (MAE), and wet extraction procedures. At present, there is limited work in the literature on UPE for the determination of trace elements in beverage samples. Our single-correlation analysis showed that the elements studied with the UPE method in hardaliye were strongly correlated with the MAE procedure. The parameters affecting the UPE experimental conditions such as ultrasound amplitude, sonication time, sample amount, extractant type, and volume were studied. Optimal experimental conditions for the extraction of the metals with the UPE procedure were as follows: 2 min of sonication; 30% amplitude; 3 mL sample volume; 5% HNO3 extraction solution; and 1 mL extractant volume for Ca, Cu, Mg, Mn, Na, and Zn in the hardaliye samples. The results in the hardaliye samples in minimum maximum mg/L with the UPE procedure were 33-63 for Ca, 0.10-0.27 for Cu, 3.9-14.4 for Mg, 1.0-3.2 for Mn, 32-58 for Na, and 0.39-1.1 for Zn. LODs were 0.0032, 0.012, 0.013, 0.009, 0.011, and 0.008 mg/L for Ca, Cu, Mg, Mn, Na, and Zn, respectively. The accuracy of the method was verified with a recovery test (in which recoveries between 95 and 110% were observed) and application to a NIST 1643e certified sample (trace elements in water). The UPE procedure was found to be fast, accurate, and simple, with fewer contaminants and lower concentrated reagent consumption in comparison with conventional extraction procedures.
Determination of some traces metal levels in cheese samples packaged in plastic and tin containers by ICP-OES after dry, wet and microwave digestion
(Pergamon-Elsevier Science Ltd, 2011) Bakircioglu, Dilek; Kurtulus, Yasemin Bakircioglu; Ucar, Gokhan
The concentrations of Cd, Co, Cr, Cu, Mn, Ni, Pb, Se and Zn in cheese samples packaged in plastic and tin containers were analyzed using inductively coupled plasma-optical emission spectrometry after microwave, wet and dry digestion processes. In order to evaluate the best digestion method, the relationships between the concentrations of trace metals in cheese samples after microwave digestion was compared by wet and dry ashings. Microwave digestion was found fast, reliable, simple, and excellent procedure in comparison with dry and wet ashing methods. The accuracy of the digestion procedures was determined by using standard reference material (GBW 07605-Tea). The order of levels of the elements in the white cheese samples packaged in tin containers was determined to be Cd < Co < Mn < Cr < Se < Pb < Cu < Ni < Zn, after microwave digestion and cream cheese samples in plastic containers Cd < Mn < Co < Cr < Se < Pb < Ni < Cu < Zn, respectively. There were considerable differences among of the studied element contents of cheese samples packaged in tin and plastic containers, indicating that cheese types and packaging materials play a key role in the content of trace metal. (C) 2010 Elsevier Ltd. All rights reserved.
Determination of zinc in edible oils by flow injection FAAS after extraction induced by emulsion breaking procedure
(Elsevier Sci Ltd, 2014) Bakircioglu, Dilek; Topraksever, Nukte; Kurtulus, Yasemin Bakircioglu
A new procedure using extraction induced by emulsion breaking (EIEB) procedure has been developed for extraction/preconcentration of zinc in various edible oils (canola oil, corn oil, hazelnut oil, olive oil, and sunflower oil) prior to its determination by the single line flow injection (FI) flame atomic absorption spectrometry (FAAS). Several parameters affecting the extraction efficiency of the procedure were investigated including the type and concentrations of surfactant, the concentration of HNO3, and the other operational conditions (emulsion breaking time and temperature). The limits of detection of 1.1 and 1.0 mu g L-1 were observed for zinc when aqueous standard and oil-based standards were added to the emulsions for calibration, respectively. The proposed procedure of combining EIEB and single line FI-FAAS can be regarded as a new procedure for the determination of zinc in edible oil samples. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.
Extraction Induced by Emulsion Breaking for Ca, Cu, Fe, Mn, Ni, and Zn Determination in Chocolate by Flame Atomic Absorption Spectrometry
(Oxford Univ Press Inc, 2022) Bakircioglu, Dilek; Kurtulus, Yasemin Bakircioglu; Topraksever, Nukte
Background Chocolate is a rich source of essential and non-essential elements. A new liquid-liquid extraction (LLE) approach, extraction induced by emulsion breaking (EIEB), is proposed in which the analyzed elements are transferred from the organic phase to the aqueous phase before measurement by flame atomic absorption spectrometry (FAAS). Objective To compare EIEB to microwave digestion (MWD) for extraction of elements from chocolate prior to FAAS. Methods EIEB parameters were varied to optimize the procedure. EIEB-FAAS was then compared to MWD-FAAS for the analysis of Ca, Cu, Fe, Mn, Ni, and Zn in milk and dark chocolate samples. A certified reference material (NIST 2384, baking chocolate) was analyzed to determine the recoveries of Ca, Cu, Fe, Mn, and Zn by the two methods. Results The optimized EIEB extraction method involves dilution of tempered chocolate with toluene, ultrasonic emulsification with acidified Triton X-114, breaking the emulsion by heating, and centrifugation to produce two well-defined phases. Analysis of dark and milk chocolate samples showed similar repeatability by EIEB-FAAS (RSDr 0.3 to 6.6% in dark and 0.5 to 8.7% in milk) and MWD-FAAS (RSDr 0.5 to 5.4% in dark and 0.7 to 10.2% in milk), with no significant difference detected between the methods for analysis of Ca, Cu, Fe, Mn, Ni, and Zn based on Student's t-test. Analysis of NIST 2384 baking chocolate certified reference material for Ca, Cu, Fe, Mn, and Zn demonstrated recoveries of 98.6 to 99.5% for EIEB-FAAS compared to 95.8 to 98.6% for MWD-FAAS. Conclusion EIEB-FAAS was shown to provide high recovery and excellent repeatability for accurate determination of Ca, Cu, Fe, Mn, Ni, and Zn from dark and milk chocolates.
Extraction of Cu, Fe, Mn, and Ni from Margarine Samples Using Extraction Induced by Emulsion Breaking Procedure Prior to Graphite Furnace Atomic Absorption Spectrometry and Comparison of Results to Provisional Tolerable Daily Intake Values
(Oxford Univ Press Inc, 2020) Kurtulus, Yasemin Bakircioglu; Bakircioglu, Dilek; Babac, Alper Can; Yurtsever, Selcuk; Topraksever, Nukte
Background: The emulsion induced by emulsion breaking (EIEB) procedure was previously reported for the extraction of copper, iron, manganese, and nickel from liquid oil samples such as vegetable oil. Objective: To optimize the EIEB procedure for determination of copper, iron, manganese, and nickel in solid oil (margarine) samples by Graphite Furnace Atomic Absorption Spectrometry (GFAAS). Methods: The extraction procedure uses a surfactant in nitric acid to form an emulsion followed by heating to break the emulsion. Optimization included variation of the test portion size, the type and concentration of the surfactant, the concentration of nitric acid in the aqueous solution, the emulsion agitation time, heating temperature, and the time required to break the emulsion. Results: Mean element concentrations of 11 margarine samples were in the following ranges: Cu 0.031-0.131 mu g/g, Fe 5.7-24.9 mu g/g, Mn 0.542-1.11 mu g/g, and Ni 0.108-0.134 mu g/g. Under the optimized extraction conditions, the detection limits (mu g/kg) were 4.8, 13, 1.5, and 23 for Cu, Fe, Mn, and Ni, respectively. The accuracy of the extraction procedure was determined by comparison to commonly used microwave digestion procedure. The EIEB results were not statistically different from the microwave digestion results when analyzed by GFAAS as determined by the statistical tests. Conclusions: The EIEB procedure was shown to be equivalent to the commonly used microwave digestion procedure for extraction of analytes from margarine samples. Highlights: The optimized EIEB extraction procedure is simple, rapid, low cost, and environmentally friendly. It has improved detection limits and allows calibration with aqueous standards.
ICP-OES Determination of Some Trace Elements in Herbal Oils Using a Three-Phase Emulsion Method and Comparison with Conventional Methods
(Atomic Spectroscopy Press Ltd, 2018) Bakircioglu, Dilek; Topraksever, Nukte; Yurtsever, Selcuk; Kurtulus, Yasemin Bakircioglu
The concentrations of cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn) were determined in five (Nettle, Linseed, Pumpkin seed, Sesame, and Chamomile) herbal oil samples, using inductively coupled plasma atomic emission spectrometry (ICP OES) after ultrasonic extraction (UE), wet digestion (WD), and the threephase emulsion method (TPE). The concentrations for Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn were found to be 0.037-0.063, 0.014-0.085, 0.735-1.243, 2.105-19.487, 0.104-0.592, 0.105-1.582, 0.025-0.125, and 1.024-2.583 mg kg(-1), respectively. The highest concentrations in the herbal oils were Cr, Fe, Mn, and Zn, in linseed oil, Cd and Pb in sesame oil, Cu in nettle oil, and Ni in chamomile oil, respectively. The three sample preparation methods investigated were compared and it was found that the results of TPE and WD are comparable. The statistical results show that the TPE and WD methods usually give similar results.
Investigation of aflatoxin and metal concentrations in animal feeds and feed ingredients from Turkey
(Acg Publications, 2021) Kurtulus, Yasemin Bakircioglu; Bakircioglu, Dilek; Kuscu, Muhammet; Topraksever, Nukte; Destanoglu, Orhan
The contents of aflatoxin B-1 (AFB(1)), aflatoxin B-2 (AFB(2)), aflatoxin G(1) (AFG(1)) aflatoxin G(2) (AFG(2)), aluminium (Al), arsenic (As), barium (Ba), calcium (Ca), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), mercury (Hg), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), nickel (Ni), phosphorus (P), lead (Pb), selenium (Se), tin (Sn) and zinc (Zn) in animal feed samples in Turkey were screened. Eighty animal feeds and feed ingredients were collected from different cities in Turkey. Aflatoxins were determined using the HPLC instrument after pre-separation using immuno affinity column, and also the instrument of ICP-MS was used for metal determinations. All types of animal feed samples have led concentrations lower than the maximum EU and Turkey regulation limit, while 1.25% and 11.8 of mixed and feed additive samples had AFB(1) and Hg concentrations higher than the maximum limits, respectively. A single correlation analysis was used to determine the relationship between AFB(1) and total AFs and metal contents in mixed animal feed samples (p<0.05). A strong positive correlation was found between As and AFB(1) and total AFs contents; whereas Cr was correlated negatively to AFB(1) and total AFs, using single correlation analyses.
Investigation of macro, micro and toxic element concentrations of milk and fermented milks products by using an inductively coupled plasma optical emission spectrometer, to improve food safety in Turkey
(Elsevier Science Bv, 2018) Bakircioglu, Dilek; Topraksever, Nukte; Yurtsever, Selcuk; Kizildere, Meltem; Kurtulus, Yasemin Bakircioglu
In this study, the quantification of macro, micro and toxic elements in milk and its products was carried out using inductively coupled plasma optical emission spectrometry (ICP-OES) after using sample preparation procedures (wet digestion, dry digestion, and microwave digestion). Samples were collected from farms and markets in Edirne, Turkey. Ca, Mg, Na, K, Cu, Fe, Mn, Zn, Al, and Ba concentrations in the farm milk and its products ranged from 823 to 1499,109-476, 218-1498, 905-1694, 0.094-0.26, 2.0-3.7, 0.014-0.105,12-5.2, 0.192-0.35 and 0.075-0.191 mg kg(-1) respectively. The results in commercial milk and milk based products (minimum-maximum in mg. kg(-1)) were: Ca 791-1518, Mg 107-518, Na 221-1594, K 901-1692, Cu 0.068-0.23, Fe 2.2-4, Mn 0.019-0.087, Zn 2-5, Al 0.124-0.40 and 0.080-0.197. Macro, micro and toxic element contents of the commercial milk and its products in this study generally were higher than that of the natural samples. However, a tolerable daily diet of these elements by the Trakya region is well below the Turkish Food Codex (TFC) levels of macro, micro and toxic elements. (C) 2016 Elsevier B.V. All rights reserved.
Investigation of trace elements in agricultural soils by BCR sequential extraction method and its transfer to wheat plants
(Springer, 2011) Bakircioglu, Dilek; Kurtulus, Yasemin Bakircioglu; Ibar, Hilmi
In this study, soil samples were collected from Edirne, Turkey in both summer and winter seasons and subjected to the modified Community Bureau of Reference (BCR) sequential extraction procedure in order to investigate the chemical partitioning of metals in soils and to predict heavy metals uptake by wheat grains which grown at the same soils. The samples were subjected to a three stage extraction procedure proposed by the BCR. The three phases that were separated out in the following order: (1) carbonate, exchangeable, (2) Fe-Mn oxides, and (3) organic matter. Metal concentrations of soil fractions and grain samples were determined by inductively coupled plasma atomic emission spectroscopy. The wheat samples were prepared to analysis using microwave acid digestion procedure. The pseudo-total concentrations of metals were determined after aqua regia digestion. The analytical accuracy of the method was evaluated by using the Standard Reference Materials (BCR 142R Light Sandy Soil, NIST 2711 Montana Soil, and NIST 2704 Buffalo River Sediment). The sum of the metal contents obtained from the modified BCR sequential extraction procedure and pseudo-total metal contents for soil samples were used to calculate recovery values. In order to evaluate the bioavailability of metals, the relationships between the wheat-metal and soil-extractable metal concentrations were compared.
Separation/Preconcentration System Based on Emulsion-Induced Breaking Procedure for Determination of Cadmium in Edible Oil Samples by Flow Injection-Flame Atomic Absorption Spectrometry
(Springer, 2015) Bakircioglu, Dilek; Topraksever, Nukte; Kurtulus, Yasemin Bakircioglu
In this work, a new procedure using extraction induced by emulsion breaking (EIEB) procedure has been developed for extraction/preconcentration of cadmium in various edible oils (canola, corn, hazelnut, olive, and sunflower oil) prior to its determination by flow injection (FI) flame atomic absorption spectrometry (FAAS). Five chemical variables (surfactant type, concentration of the surfactant, concentration of the nitric acid, emulsion breaking time, and temperature) were selected as the main factors affecting extraction efficiency, and two variables (sample flow rate and sample volume) were studied for optimizing flow injection conditions. The limits of detection of 1.53 and 1.55 mu g L-1 were observed for cadmium when aqueous standard and oil-based standards were added to the samples for calibration, respectively. The linear range of cadmium in aqueous standard was varied in the range of 5.994 mu g L-1. The precision of the EIEB procedure was obtained as 4.1 % by determination of ten replicates of 2.5 mu g L-1 of cadmium, and the preconcentration factor 13.8 was obtained from only 4 mL of edible oil samples. The accuracy of the procedure was performed by comparison with the reference method based on the digestion of samples in a closed-vessel microwave oven and by spiking the samples with the known amounts of the cadmium in the form of oil-based standards. There were no statistical differences between the results obtained with the EIEB procedure and the reference microwave digestion method, and the recoveries were in the range of 97-104 %.

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