Dilek Bakircioglu

Determination of some traces metal levels in cheese samples packaged in plastic and tin containers by ICP-OES after dry, wet and microwave digestion.

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.

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.

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 mgkg(-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%.

Biosorption of lead by filamentous fungal biomass-loaded TiO2 nanoparticles.

In this study filamentous fungal biomass-loaded TiO(2) nanoparticles were used for the biosorption of lead(II) ions by flow-injection system coupled to flame atomic absorption spectrometry. The effects of pH, sample volume, loading and elution flow rates, eluent type and volume on the recovery of lead were investigated. Lead ions were sorbed on a biosorbent minicolumn at pH 4.0 followed by an elution step using 288 microL of 1.0 mol/L hydrochloric acid solution. The limit of detection was 0.78 microg/L. The validation of the described procedure was performed by the analysis of certified reference material (NRC-CNRC NASS-5 seawater). Finally, the presented biosorption procedure was applied to the determination of lead in tap water and seawater samples.

Investigation of trace elements in agricultural soils by BCR sequential extraction method and its transfer to wheat plants

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.

Determination of zinc in edible oils by flow injection FAAS after extraction induced by emulsion breaking procedure.

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 μg 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.

Solid Phase Extraction of Bismuth and Chromium by Rice Husk

Abstract A major agricultural waste, rice husk and its ash were used for the preconcentration and separation of bismuth and chromium prior to their determination by flame atomic absorption spectrometry (FAAS) and their sorption properties with respect to bismuth and chromium from water samples were investigated. For this purpose, rice husk was thermally treated at 300°C for one hour and 600°C for ten hours in a muffle furnace. The effects of various experimental conditions on retention and elution efficiencies of studied elements for untreated rice with husk, untreated and thermally treated rice husk were investigated by applying batch and column methods. The analyte elements were quantitatively collected on rice with husk, the untreated and thermally treated rice husk at 300°C if the pH is above 3. The analyte elements retained on the rice with husk, rice husk or its ash were completely recovered by means of 2.0 M hydrochloric acid. Maximum chromium adsorption capacities of untreated rice with husk (URH), rice husk (RH), rice husk ash heated at 300°C (RHA-300) and 600°C (RHA-600) are 0.12, 0.50, 19.09 and 6.49 mg Cr/g adsorbent, respectively and 0.47, 294, 18.34 and 4.90 mg Bi/g adsorbent, respectively. When RHA-300 was used which is the most suitable adsorbent of all, detection limits (3 δ) were 1.3 µg/L for Bi and 1.5 µg/L for Cr. The relative standard deviations for the determinations were found to be 1.0–7.9%. The results showed that RHA especially heated at 300°C could be used as an efficient and cheap adsorbent for the removal of some heavy metals from the natural water samples and for the preconcentration and separation of bismuth and chromium prior to their determination by flame atomic absorption spectrometry.

Determination of metal ions in water and tea samples by flame-AAS after preconcentration using sorghum in nature form and chemically activated

Sorghum-agricultural waste in nature (SAWN) and chemically activated with phosphoric acid (SAWAC) was used as a solid phase extraction material for determination of cadmium, copper, manganese and lead ions in aqueous solutions by flame atomic absorption spectrometry (FAAS). The effect of pH, sample flow rate and volume, eluent type, volume and flow rate, and the effects of potentially interfering ions on the recovery of the analytes were investigated. Adsorption capacity of SAWN and SAWAC was determined by batch method under the optimized conditions. Adsorption capacity of SAWAC was found to be 9.53, 11.77, 11.64, and 15.01 mg/L for Cd, Cu, and Mn and Pb ions, respectively. The limit of detection (LOD) for the analytes was found in the range of 0.16–1.21 μg/L with a theoretical preconcentration factor of 50. The method was validated by analyzing certified material (GBW 07605-Tea) and the results were in a good agreement with the certified value. In addition, the proposed method was applied to the determination of analytes in tea and river water samples.

Evaluation of Syringe‐Connected Minicolumn Technique for Preconcentration of Some Trace Elements Using Chromosorb‐103 and Determination by Flame Atomic Absorption Spectrometry

Abstract A syringe‐connected minicolumn (SCM) technique has been developed for preconcentration and enrichment of cobalt, iron, and lead in river‐water samples prior to their determination by flame atomic absorption spectrometry (FAAS). The proposed technique is substituted for the classical batch and column techniques all of which are off‐line methods. The method proposed was compared with the column technique with respect to easiness, rapidness, simplicity and some analytic performances such as recovery, precision, accuracy and risk of contamination. The minicolumn was filled with Chromosorb‐103 as a sorbent. In order to retain the analyte elements, the sample solution was drawn into the syringe and discharged back passing through the sorbent in the minicolumn. The analyte elements were quantitatively retained at pH ≥4 if they were complexed with ammonium pyrrolidine dithiocarbamate (APDC) prior to passing through to the sorbent. The analytes sorbed on the minicolumn was then eluted with 1.0 mol L−1 HNO3 in acetone again drawing and discharging the eluent. Optimum flow rates of sample or eluent for sorption and elution procedure were 20 mL min−1 for both drawing and discharging cases. The proposed technique was successfully applied to the determination of analytes in certified reference material and spiked river‐water samples. The recoveries of analytes from certified reference material (Bovine liver) and river‐water samples were quantitative and reproducible (>96%, with relative standard deviation (RSD) of 1–5%). The developed technique is simple, fast, and accurate. Detection limits (3σ) were 4.8 µg L−1 for Co, 14 µg L−1 for Fe, and 15 µg L−1 for Pb. Very high preconcentration factors up to 200‐fold could be achieved.

Online solid phase preconcentration using EGDMA–MAA copolymer for lead determination by FAAS

A Ethylene glycol dimethacrylate (EGDMA) methacrylic acid (MAA) resin was used for preconcentration of lead at trace levels in water samples. For this purpose, a flow-injection, solid phase extraction method was developed for the determination of lead by flame atomic absorption spectrometry. Lead ions were sorbed on a EGDMA–MAA column at pH 4, followed by an elution step using 288 µL of 4.0 M nitric acid solution and determination by flame atomic absorption spectrometry. Optimum conditions for quantitative sorption involving the pH, sample volume, loading and elution flow rates, eluent type, and volume were investigated. A 868-fold enrichment factor could be reached. The detection limit for the water samples, estimated from the noise on the signal obtained for 250 mL of 10 µg L−1 loaded at 4.9 mL min−1 was 1.04 µg L−1. The method was applied for lead determination in river water samples collected in Edirne, Turkey. Recoveries of spiked solutions (10 µg L−1) to river water samples were quantitative. Finally, the method was validated by the analysis of certified reference material SRM 2704 (Buffalo River Sediment).

Determination of Several Element Levels in Hardaliye Beverages Using Flame Atomic Absorption Spectrometry After Ultrasound-Probe Extraction

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.