Ali Rehber Türker

Separation and speciation of Cr(III) and Cr(VI) with Saccharomyces cerevisiae immobilized on sepiolite and determination of both species in water by FAAS

A rapid, sensitive and accurate method for the separation, preconcentration and determination of Cr(III) and Cr(VI) in water samples is described. Chromium species can be separated by biosorption on Saccharomyces cerevisiae immobilized on sepiolite and determined by flame atomic absorption spectrometry (FAAS). The optimum conditions for separation and preconcentration (pH, bed height, flow rate and volume of sample solution) were evaluated. Recovery of the chromium was 96.3+/-0.2% at 95% confidence level. The breakthrough capacity of the adsorbent was found as 228 mumol g(-1) for Cr(III). The proposed method was applied successfully to the determination of Cr(III) and Cr(VI) in spiked and river water samples.

Synthesis of nano B2O3/TiO2 composite material as a new solid phase extractor and its application to preconcentration and separation of cadmium

A new solid phase extractor, nano-scale diboron trioxide/titanium dioxide composite material, was synthesized and used for separation and/or preconcentration of trace cadmium ion from various samples. The characterization of the synthesized material was performed by scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffractometer methods (XRD). The specific surface area of the material was also determined and found as 3.4m(2)/g. Analytical parameters including pH of sample solution, sample volume, flow rate of sample solution, volume and concentration of eluent for the column solid phase extraction (SPE) procedure were examined. The effect of common matrix ions on the recovery of the cadmium has also been investigated and found that they did not interfere on cadmium preconcentration. Under the optimum experimental conditions, preconcentration factor and analytical detection limit were determined as 50 and 1.44 microg/L, respectively. The reusability (stabile up to 100 run) and adsorption capacity (49 mg/g) of the sorbent were excellent. The accuracy of the method was confirmed by analyzing certified reference materials (Tea leaves GBW-07605). The results demonstrated good agreement with the certified values (relative error <10%). The precision of the method was also satisfactory. The recovery of cadmium under the optimum conditions was found to be 96+/-3% at 95% confidence level. The method was applied for the determination of cadmium in tap water and tea leaves.

Determination of iron and nickel by flame atomic absorption spectrophotometry after preconcentration on Saccharomyces cerevisiae immobilized sepiolite.

Iron and nickel have been preconcentrated on Saccharomyces cerevisiae immobilized sepiolite and determined by flame atomic absorption spectrophotometry (FAAS). Preconcentration studies were conducted by the column method. Effect of pH, amount of adsorbent, elution solution, flow rate and interfering ions on the recovery of the analytes have been investigated. Recoveries of Fe and Ni were 95+/-1 and 99.5+/-0.1%, respectively, at 95% confidence level. The breakthrough capacities of analytes were also investigated and found to be 0.042 mmol g(-1) for Fe and 0.055 mmol g(-1) for Ni. The proposed method was applied to the determination of iron and nickel in brass (NBS SRM 37e). The detection limit of iron and nickel were found as 0.065 and 0.087 mug ml(-1), respectively. The direct determination of trace metals by flame atomic absorption spectrometry (FAAS) is limited and difficult because of low concentration and/or matrix interferences. The proposed method is excellent for the determination of trace metal in matrixes, such as metal alloys.

Flame atomic absorption spectrometric determination of silver after preconcentration on Amberlite XAD-16 resin from thiocyanate solution.

A method of silver preconcentration by using a column containing Amberlite XAD-16 resin and this future determination by a flame AAS after elution is proposed. The effect of the factors such as pH, the nature of complexing agent, sample volume, flow rate, the type and concentration of elution solution on the preconcentration efficiency have been investigated. The influence of some matrix elements on the recovery of silver were also examined. It was found, that the quantitative recovery of thiocyanate complex of silver was obtained from nitric acid solution (pH 2) as 99.20+/-0.07% at the 95% confidence level. A preconcentration factor up to 75 could be obtained. The detection limit of silver was 0.047 mg l(-1). The adsorption of silver onto Amberlite XAD-16 can be formally described by a Langmuir equation with maximum adsorption capacity 4.66 mg g(-1) (0.043 mmol g(-1)). The proposed method was applied to determination of silver in standard alloy with relative error 6.25%.

Determination of Cu, Zn, Fe, Ni and Cd by flame atomic absorption spectrophotometry after preconcentration by Escherichia coli immobilized on sepiolite.

A method for the determination of Cu, Zn, Fe, Ni and Cd by flame atomic absorption spectrophotometry (FAAS) after preconcentrating on a column containing Escherichia coli immobilized on sepiolite has been developed. Optimum pH values, amount of adsorbent, elution solution and flow rate have been obtained for the elements studied. The effect of interfering ions on the recovery of the analytes has also been investigated. Recoveries of Cu, Zn, Fe, Ni and Cd by E. coli immobilized on sepiolite were 99.1+/-0.6, 98.2+/-0.6, 98.1+/-0.5, 97.2+/-0.8 and 98.2+/-0.4% at 95% confidence level, respectively. The adsorption capacity of E. coli immobilized on sepiolite was found as 0.148, 0.064, 0.098, 0.134 and 0.088 mmol/g for Cu, Zn, Fe, Ni and Cd, respectively. The proposed method was applied to the determination of trace metals in alloys (NBS SRM 85b). Trace metals have been determined with relative error lower than 10%.

Separation, Preconcentration and Speciation of Metal Ions by Solid Phase Extraction

This review presents the most recent applications of solid phase extraction for the separation, preconcentration and speciation of metals, metalloids, and organometals. The review focuses on solid phase, column treatments and on the applications of this technique to various samples. This review also intends to discuss some applications and limitations associated to solid phase extraction techniques due to the necessity on limited selectivity. Nevertheless, the solid phase extraction is still an efficient, sensitive and inexpensive technique to perform removal of metal ions from environmental samples, preconcentration of metal ions for analytical purposes and speciation of the metal and metalloids as shown by the variety of applications presented and discussed in this review. A literature survey of the last three years (2008–2010) offering a critical review of solid phase extraction for separation, preconcentration and speciation of metal ions from various sample matrices is provided.

Chelating agent free-solid phase extraction (CAF-SPE) of Co(II), Cu(II) and Cd(II) by new nano hybrid material (ZrO2/B2O3)

New nano hybrid material (ZrO(2)/B(2)O(3)) was synthesized and applied as a sorbent for the separation and/or preconcentration of Co(II), Cu(II) and Cd(II) in water and tea leaves prior to their determination by flame atomic absorption spectrometry. Synthesized nano material was characterized by scanning electron microscope, transmission electron microscope and X-ray diffraction. The optimum conditions for the quantitative recovery of the analytes, including pH, eluent type and volume, flow rate of sample solution were examined. The effect of interfering ions was also investigated. Under the optimum conditions, adsorption isotherms and adsorption capacities have been examined. The recoveries of Co(II), Cu(II) and Cd(II) were 96 ± 3%, 95 ± 3%, 98 ± 4% at 95% confidence level, respectively. The analytical detection limits for Co(II), Cu(II), and Cd(II) were 3.8, 3.3, and 3.1 μg L(-1), respectively. The reusability and adsorption capacities (32.2 mg g(-1) for Co, 46.5 mg g(-1) for Cu and 109.9 mg g(-1) for Cd) of the sorbent were found as satisfactory. The accuracy of the method was confirmed by analyzing certified reference material (GBW-07605 Tea leaves) and spiked real samples. The method was applied for the determination of analytes in tap water and tea leaves.

Atomic absorption spectrometric determination of Fe(III) and Cr(III) in various samples after preconcentration by solid-phase extraction with pyridine-2-carbaldehyde thiosemicarbazone

An atomic absorption spectrometric method for the determination of Fe(III) and Cr(III) after solid-phase extraction of their Schiff-base chelates by a column procedure with Amberlite XAD-4 was developed. A Schiff base, pyridine-2-carbaldehyde thiosemicarbazone (PCTSC), was synthesized and used as a chromogenic reagent for solid-phase extraction of Fe(III) and Cr(III) ions in the column procedure. The influence of various analytical parameters including the amount of solid phase, pH, type of elution solution, volume of sample solution, and flow rate of sample solution on the extraction efficiency of analytes were investigated. The recoveries of Fe(III) and Cr(III) were 99 ± 1 and 98 ± 2%, respectively, at the 95% confidence level under the optimum conditions. Fe(III) and Cr(III) were preconcentrated up to 25-fold. The limit of detection of Fe(III) and Cr(III) are 4.1 and 3.72 µg/L, respectively. The proposed method was applied to the determination of these metal ions in tap water, river water, Atatürk Dam water, and alloy samples. The relative standard deviation and the relative error are lower than 6%.

Determination of lead in cookies by electrothermal atomic absorption spectrometry with various chemical modifiers.

Abstract The determination of lead in some Turkish cookies has been studied in the presence of some chemical modifiers. In order to decrease the interferences of sample matrix and to stabilize the atomic absorption signal of lead, W, Pd, W+Pd and W+Pd+tartaric acid (TA) have been tested as matrix modifier. Modifiers have been compared in terms of pyrolysis temperature, atomization and background profiles, precision and accuracy. The W+Pd+TA modifier mixture was found to be preferable for the determination of lead in cookies. The recovery and limit of detection of lead were about 99% and 1.2 μg/l, respectively.

Preconcentration, Speciation, and Determination of Mercury by Solid Phase Extraction with Cold Vapor Atomic Absorption Spectrometry

In this study, inorganic mercury [iHg (Hg2+)] and monomethylmercury [MeHg (CH3Hg+)] ions have been preconcentrated and determined by a column solid phase extraction method. Cold vapor atomic absorption spectrometry was used for the determination of mercury species. Optimum retention and elution parameters were determined for both mercury species separately. For this purpose, the effect of pH, flow rate and volume of sample solution, type, and concentration of eluent on the recovery of mercury species were investigated. Effects of possible interfering ions were also studied. Optimum values of flow rate, pH, and volume of sample solution were found to be 3 mL min−1, 4.0 and 50 mL, respectively, for both iHg and MeHg ions. Although the both species were retained at pH 4, the elution could be performed only with different eluents. While MeHg ions were eluted with 10 mL of 0.1 mol/L HCl solution, iHg ions were eluted with 10 mL of 0.2 mol L−1 thioureasolution in 3 mol L−1HCl. Limits of detection for iHg and MeHg were 0.44 µg L−1 and 0.56 µg L−1, respectively. To validate the proposed speciation and/or preconcentration method, a certified reference material (ERM-CE464) was analyzed and MeHg was determined with a relative error of 7.3%. The accuracy was also checked by analyzing spiked water and fish samples for both species.