Ahmet Ülgen

A solid phase extraction procedure for the determination of Cd(II) and Pb(II) ions in food and water samples by flame atomic absorption spectrometry

A relatively rapid, accurate and precise solid phase extraction method is presented for the determination of cadmium(II) and lead(II) in various food and water samples. Quantitation is carried out by flame atomic absorption spectrometry (FAAS). The method is based on the retention of the trace metal ions on Dowex Marathon C, a strong acid cation exchange resin. Some important parameters affecting the analytical performance of the method such as pH, flow rate and volume of the sample solution; type, concentration, volume, flow rate of the eluent; and matrix effects on the retention of the metal ions were investigated. Common coexisting ions did not interfere on the separation and determination of the analytes. The detection limits (3 σb) for Cd(II) and Pb(II) were found as 0.13 and 0.18 μg L(-1), respectively, while the limit of quantification values (10 σb) were computed as 0.43 and 0.60 μg L(-1) for the same sequence of the analytes. The precision (as relative standard deviation was lower than 4% at 5 μg L(-1) Cd(II) and 10 μg L(-1) Pb(II) levels, and the preconcentration factor was found to be 250. The accuracy of the proposed procedure was verified by analysing the certified reference materials, SPS-WW2 Batch 108 wastewater level 2 and INCT-TL-1 tea leaves, with the satisfactory results. In addition, for the accuracy of the method the recovery studies (⩾ 95%) were carried out. The method was applied to the determination of the analytes in the various natural waters (lake water, tap water, waste water with boric acid, waste water with H2SO4) and food samples (pomegranate flower, organic pear, radish leaf, lamb meat, etc.), and good results were obtained. While the food samples almost do not contain cadmium, they have included lead at low levels of 0.13-1.12 μg g(-1).

An on-line preconcentration/separation system for the determination of bismuth in environmental samples by FAAS

An on-line preconcentration procedure for the determination of bismuth by flame atomic absorption spectrometry (FAAS) has been described. Lewatit TP-207 chelating resin, including iminodiacetate group, packed in a minicolumn was used as adsorbent material. Bi(III) was sorbed on the chelating resin, from which it could be eluted with 3 mol L(-1) HNO(3) and then introduced directly to the nebulizer-burner system of FAAS. Best preconcentration conditions were established by testing different resin quantities, acidity of sample, types of eluent, sample and eluent solution volumes, adsorption and elution flow rates, and effect of interfering ions. The detection limit of the method was 2.75 microg L(-1) while the relative standard deviation was 3.0% for 0.4 microg mL(-1) Bi(III) concentration. The developed method has been applied successfully to the determination of bismuth in pharmaceutical cream, standard reference materials and various natural water samples with satisfactory results.

Development of a new on-line system for the sequential speciation and determination of chromium species in various samples using a combination of chelating and ion exchange resins

A new on-line flow injection (FI) procedure for the sequential separation, preconcentration and speciation of Cr(III)/Cr(VI) species in different matrices is described based on the combining of solid phase extraction and flame atomic absorption spectrometry (FAAS). Poly 2-(5-methylisoxazol)methacrylamide-co-2-acrylamido-2-methyl-1-propanesulfonic acid-co-divinyl-benzene and Dowex 21K resins were used as chelating and ion-exchange materials for the separation/preconcentration of Cr(III) and Cr(VI) ions, respectively. Trace amounts of chromium retained on the resins were eluted sequentially with HNO3 and then introduced directly to the nebulizer-burner system of FAAS. The optimum conditions such as pH of the sample solution, amount of the resin, volume of the sample and interfering ions, which are effective on the quantitative recovery of the analytes, were investigated for sequential determination of Cr(III) and Cr(VI) ions. The preconcentration factors were found to be 48 and 30 for Cr(III) and Cr(VI), and the detection limits corresponding to three times the standard deviation of the blank (3s/b) were 0.05 and 0.3 µg L(-1), respectively. The method was verified by analyzing a certified reference material. The proposed method was applied to the determination based on the speciation of chromium in various real samples with satisfactory results.

Determination of some metal ions in various meat and baby food samples by atomic spectrometry.

In this paper, we report a simple and rapid solid phase extraction system for the separation/preconcentration and determination of Cd(II), Co(II), Cu(II), Fe(III), Cr(III), Pb(II), and Zn(II) ions by flame atomic absorption spectrometry (FAAS). This method is based upon the retention of metal ions on a column packed with poly[N-(3-methyl-1H-indole-1-yl)]-2-methacrylamide-co-2-acrylamido-2-methyl-1-propane sulphonic acid-co divinylbenzene] (MMAD) resin as a solid-phase extraction (SPE) sorbent at pH 8. At the optimized conditions, the limits of detection (3 s/b) between 0.12 and 1.6 μg L(-1), preconcentration factor of 100, and the relative standard deviation of ⩽1.8% were achieved (n=10). The accuracy of the method was verified by analyzing certified reference materials (CRMs) and performing recovery experiments. The developed method was successfully applied to the various natural water, meat products and baby food samples. The recoveries of analyte ions were found in added real samples and CRMs from 95% to 102%.

Synthesis, characterization and application of a new chelating resin for on-line separation, preconcentration and determination of Ag(I) by flame atomic absorption spectrometry.

A simple and reliable on-line separation/preconcentration procedure was developed for the determination of trace levels of Ag(I) by flame atomic absorption spectrometry. Poly[N-(3-methyl-1H-indol-1-yl)-2-methacrylamide-co-2-acrylamido-2-methyl-1-propane sulfonic acid-co-divinylbenzene] was synthesized and characterized as a new chelating resin for the first time. Ag(I) was sorbed on the chelating resin, from which it could be eluted with 3 mol L(-1) HCl and then introduced directly to the nebulizer-burner system for flame atomic absorption spectrometry. The parameters influential on the determination of Ag(I) ions such as the pH of the sample solution, amount of resin, eluent type, interfering ions and flow variables were studied. Under the optimum conditions, the calibration graph obtained was linear over the concentration range of 2-20 μg L(-1). The detection limit of the method (3σ) was 0.3 μg L(-1) while precision was 1.5% (n=25) at the level of 10 μg L(-1) Ag(I). The limit of quantification for the method, based on 20 σ, was 2.0 μg L(-1). The enrichment factor was found to be 65 while the optimized sample volume was 13.6 mL. The accuracy of the method was performed by analyzing certified reference materials. The developed method was applied successfully for the determination of silver in different water samples with satisfactory results.

On-line preconcentration/determination of zinc from water, biological and food samples using synthesized chelating resin and flame atomic absorption spectrometry

An on-line flow injection pre-concentration-flame atomic absorption spectrometry method was developed to determine trace zinc in water (tap, dam, and well water), biological (hair and nail), and liver samples. As a solid phase extractant, a synthesized new chelating resin, poly(2-thiozylmethacrylamide-co-divinylbenzene-co-2-acrylamido-2-methyl-1-propane sulfonic acid) was used. The resin was characterized by Fourier transform infrared spectroscopy, elemental analysis, and surface area by nitrogen sorption. A pre-concentration factor of 40-fold for a sample volume of 12.6 mL was obtained by using the time-based technique. The detection limit for the pre-concentration method was found to be 2.2 μg L(-1). The precision (as RSD,%) for 10 replicate determinations at the 0.04 μg mL(-1) Zn concentration was 1.2%. The calibration graph using the pre-concentration system for zinc was linear with a correlation coefficient of 0.998 in the concentration range from 0.005 to 0.05 μg mL(-1). The applicability and accuracy of the developed method were estimated by the analysis spiked water, biological, liver samples (83-105%), and also certified reference material TMDA-70 (fortified lake water) and SPS-WW1 Batch 111-Wastewater. The results were in agreement with the certified values.

On-line determination of palladium by flame atomic absorption spectrometry coupled with a separation/preconcentration minicolumn containing a new sorbent

A method was developed for the on-line determination of palladium in complex matrices with flame atomic absorption spectrometry (FAAS) using Amberlite XAD-16 resin functionalized with 2-[2-(5-thiol-1,3,4-thiadiazolyl)]-azonaphthol (TTAN) reagent. Optimum experimental conditions such as pH of sample, type of eluent, amount of resin, volumes of sample and eluent solution, flow rates of sample and eluent, and effect of interfering ions were established. A 0.1 mol L−1 thiourea solution in 0.5 mol L−1 HCl was used as the eluent and subsequently transportation the analyte ions into the nebulizer–burner system for atomization. The synthesized chelating resin material showed excellent chemical and mechanical resistance, fast adsorption kinetics permitting the use of high sample flow rates without significant losses of retention efficiency. The detection limit of the method was 1.5 µg L−1 while the relative standard deviation (RSD%) was 2.4% at 0.1 mg L−1 Pd(II) level. The developed method was successfully applied to the determination of palladium in the catalytic converter and water samples.

On-line solid-phase separation/preconcentration for the determination of copper in urine by flame atomic absorption spectrometry

A new on-line separation/preconcentration system was developed for the determination of Cu(II) ions by flame atomic absorption spectrometry in urine samples. A newly synthesized chelating resin, by anchoring eriochrome blue black R reagent to Amberlite XAD-16 resin, was used as a packing material for the selective separation/preconcentration of Cu(II) ions. The influence of the parameters on the determination of Cu(II) ions such as pH of sample solution, amount of the resin, eluent type, interfering ions and flow variables was studied. The detection limit of the method was 1.0 μg L(-1) while precision was 2.3% (n=15) at 50 μg L(-1) Cu(II) level. The adsorption capacity of the resin was 217 μg g(-1) Cu(II). The accuracy of the method was proven using TMDA-64 standard lake water and synthetic urine sample. The developed method has been applied successfully to the determination of copper in urine with satisfactory results.

Real-Time Monitoring of Indigo Concentrations in the Dyebath with a Laser Diode Spectrometer

A laser diode absorption spectrometer is coupled with a continuous dilution system for real-time monitoring of indigo dyeing of denim yarn. The reduced form of indigo in the dyebath is continuously pumped by a peristaltic pump into a mixing cuvette, where it is diluted by a factor of 80 with aerated water and oxidized into its stable form. This solution is then pumped into the sampling cell of the laser diode spectrometer for absorption measurements. Monochromatic radiation emitted from the laser diode at 635 nm is used to measure indigo absorption at the shoulder of a broad absorption peak. A linear calibration curve is obtained in a concentration range between 10 and 150 mg/L with a linear regression coefficient of r2 = 0.9993, which corresponds to indigo concentrations in the dyebath covering the range between 0.8-12 g/L. This range exceeds indigo concentrations typically used in industry, which range between 1-3 g/L. The reproduc ibility of measurements is 0.5%. In this technique, there is no interference due to sulfur compounds present in the dyebath, which is a problem with electrochemical titration methods commonly used for indigo determinations.

An on-line separation and preconcentration system coupled with flame atomic absorption spectrometry for the determination of lead

A simple on-line separation/preconcentration procedure is described for the determination of trace levels of Pb(II) by flame atomic absorption spectrometry (FAAS). A mini-column packed with Dowex Marathon C (DMC) ion-exchange resin was used for the on-line preconcentration of Pb(II) at pH 3.5. Pb(II) was sorbed on the resin, from which it could be eluted with 3 mol L−1 HCl and then introduced directly to the nebulizer–burner system of FAAS. The parameters influential on the determination of Pb(II) ions such as the pH of sample solution, eluent type, interfering ions and flow variables were studied. Under the optimum conditions, the calibration graph obtained was linear over the concentration range of 0.01–0.1 mg L−1. The detection limit of the method was 1.3 μg L−1 while precision was 1.1% (n = 15) at a 0.05 mg L−1 Pb(II) level. The accuracy of the method was proven using standard reference materials. The developed method has been applied successfully to the determination of lead in water and various environmental samples with satisfactory results.