Mustafa Ozcan

Solid-phase extraction of bismuth, lead and nickel from seawater using silica gel modified with 3-aminopropyltriethoxysilane filled in a syringe prior to their determination by graphite furnace atomic absorption spectrometry.

In this study, the use of syringe filled with sorbent for the separation and enrichment of bismuth, lead and nickel prior to their analysis by graphite furnace atomic absorption spectrometry was described to substitute for batch and column techniques. The method proposed in this paper was compared with column technique with respect to easiness, fastness, simplicity, recovery and risk of contamination. The syringe was filled with 0.5 g of sorbent and in order to retain the analyte elements, 5 ml of sample solution (pH>/=5) was drawn into the syringe to 15 s and discharged again in 15 s. Then, 2.0 M of HCl, as the eluent, was drawn into the syringe and ejected back to desorb the analyte elements. At optimum conditions, the recoveries of Bi, Pb and Ni were 95-99% with relative standard deviations (RSDs) of around +/-2%. Detection limit (delta) was 0.5 mug l(-1) for Bi, Pb and Ni, respectively. The elements could be concentrated by drawing and discharging several portions of sample successively but eluting only one time. Bi, Pb and Ni added to a seawater sample were quantitatively recovered (>95%) with low RSD values of around +/-2-3%. The risk of contamination is less than that with the column technique. In addition, it is much faster, simpler, easier, more practical and handy compared with column technique.

Chromatographic profiles and identification of new phenolic components of Ginkgo biloba leaves and selected products.

Ginkgo biloba leaves and their extracts are one of the most widely used herbal products and/or dietary supplements in the world. A systematic study of the phenolic compounds is necessary to establish quality parameters. A modified LC-DAD-ESI/MS method was used to obtain chromatographic profiles for the flavonoids and terpene lactones of Ginkgo biloba leaves. The method was used to identify 45 glycosylated flavonols and flavones, 3 flavonol aglycones, catechin, 10 biflavones, a dihydroxybenzoic acid, and 4 terpene lactones in an aqueous methanol extract of the leaves. The extracted G. biloba leaf products contained the same flavonoids as the raw leaves except for the lack of biflavones. The detected glycosylated flavonol contents were equal to or more than 0.0008% of the dry plant material. This is the first report of the presence of more than 20 of these flavonoids in G. biloba.

A rapid method for the determination of Pb, Cu and Sn in dried tomato sauces with solid sampling electrothermal atomic absorption spectrometry

In this work, lead, copper and tin were determined in tomato sauces by solid sampling graphite furnace atomic absorption spectrometry (SS-GFAAS) and the results were compared with those obtained after sample digestion. The tomato sauce samples were dried at 90 °C for 12 h and directly introduced into the graphite furnace by means of solid auto sampler. Alternatively the dried samples were digested with concentrated HNO(3) (65%) and pipetted into the graphite furnace. After the optimization of the experimental parameters, the average lead, copper and tin concentrations found by the solid sampling and digestion methods in 10 different kinds of tomato sauce samples were not significantly different at 95% confidence level. For solid sampling technique, the limits of detection (LOD) for Cu, Sn and Pb were 10.4, 3.2 and 0.4 ng/g, respectively. Whereas for digestion method, for Cu, Sn and Pb were 6.7, 2.7 and 0.3 ng/g, respectively. The proposed solid sampling technique was fast, simple, the risks of contamination and analyte loss were low.

Use of a syringe-mountable filter resin technique for the separation and enrichment of lead and cadmium prior to their determination by flame atomic absorption spectrometry

The use of a syringe-mountable filter resin (SMFR) technique for the separation and enrichment of lead and cadmium prior to their determination by flame atomic absorption spectrometry is described as a substitute for batch and column techniques. The proposed method was compared with the column technique with respect to ease of use, speed, reproducibility, simplicity, recovery and risk of contamination. The housing of a syringe-mountable membrane filter was filled with Dowex HCR cationic resin and mounted on to the tip of a plastic syringe. The sample solution was drawn into the syringe, passing through the resin and discharged manually. The elements sorbed by the resin were then quantitatively eluted by drawing and discharging 2.5 M HCl as the eluent. Under the optimum conditions, the recoveries of Pb and Cd were 98–99% with relative standard deviations (RSDs) of around 2%. Detection limits (3σ) were 14 µg l−1 for Pb and 10 µg l−1 for Cd. The elements could be concentrated by drawing and discharging several portions of sample successively but eluting only once. Pb and Cd added to a sea-water sample were quantitatively recovered (>95%) with low RSD values of around 2–3%. The proposed method is inexpensive, simple and precise. The risk of contamination is less than with the column technique. In addition, the method is much faster, easier and more practical than the column technique.

Investigation of the effect of some inorganic salts on the determination of tin in graphite furnace atomic absorption spectrometry

Abstract The interference mechanisms of sulfate and chloride salts of sodium, potassium and nickel on tin in graphite furnace atomic absorption spectrometry were studied by using a dual cavity platform. For this purpose, different sets of experiments such as pyrolysis curves for mixed and separated solutions of analyte and interferent, background signals in the pyrolysis stage, and atomization from tube wall and platform were investigated. It was found that sodium and potassium chlorides and sulfates cause gas phase reactions between the analyte and decomposition products of the interferent and/or expulsion of analyte vapor from the furnace together with rapidly expanding matrix gases in the atomization step. The interference effects of nickel chloride and sulfate depend on the pyrolysis temperature. At low pyrolysis temperatures interferents do not change their chemical form, and cause gas phase and/or expulsion interferences in the atomization step. At elevated temperatures both salts are converted to NiO which does not cause interferences any more, and even acts as a modifier for tin. When the sample is atomized from the wall, interferences were always more pronounced than for atomization from the platform because of the more extensive gas-phase and/or expulsion interferences.

The spatial distribution and photometric and analytical accuracy of Sn determined by graphite furnace atomic absorption spectrometry in the presence of sulfates and palladium

The vertical spatial distribution of Sn in the graphite furnace was determined in the presence of 0.5% HCl (standards) and 10 µg of KCl, K2SO4, and NiSO4, with and without 5 µg of Pd, using a spectrometer capable of measuring spatially resolved absorbance. A normal gradient (decreasing concentration with increasing height in the furnace) was observed for Sn in HCl and KCl. This gradient was dramatically reversed in the presence of K2SO4 (at all pyrolysis temperatures) and NiSO4 (at pyrolysis temperatures below 900 °C) and was accompanied by poor analytical recoveries. Accurate analytical recoveries and a normal gradient were obtained for NiSO4 when a pyrolysis temperature of 900 °C was used. Pd yielded normal gradients statistically different (steeper) than those obtained with Sn Standards in HCl. The gradient for Sn in the presence of Pd was not affected by 10 µg of KCl, K2SO4, and NiSO4. Accurate analytical recoveries were obtained for Sn in Pd in all the matrices tested in this study and at all pyrolysis temperatures. The change in the Sn gradient induced by KCl, K2SO4, and NiSO4 resulted in photometric errors that are problematic for conventional, line-source AAS. Selection of the height of the viewing region within the furnace can exacerbate or improve the analytical recoveries. The constant Sn gradient established by Pd removed photometric error as an error source in the determination of Sn.

Simultaneous determination of Co, Al and Fe by HR CS-GFAAS

In this study, simultaneous determination of Al, Co and Fe by high resolution continuum source graphite furnace atomic absorption spectrometer (HR-CS GFAAS) was performed satisfactorily. For this purpose, the spectral area between 237.148 and 237.403 was monitored and Al, Co and Fe absorbances were detected at absorption lines, 237.312 nm, 237.185+237.283+237.386 nm and 237.362 nm, respectively. The characteristic concentrations and LOD values for the working wavelengths of Co, Al, and Fe were 48.0, 6.00, 54.0 µg L(-1), and 12.0, 14.0, 16.0 µg L(-1), respectively. The linear working ranges were spread over 0.01-10, 0.05-2.5 and 0.05-10 mg L(-1) for Co, Al, and Fe, respectively. In the end, Al, Co and Fe in several certificated reference materials and waste water samples were determined satisfactorily by HR-CS GFAAS. With this proposed method a fast and straightforward simultaneous determination by HR CS AAS shown as possible.

Atomic Absorption Spectrometric Determination of Lead and Cadmium in Waste Water Samples After Enrichment and Separation Using Purolite C-100 E Resin Filled in a Syringe-Mountable Filter

Abstract In this study a new hopeful enrichment/separation technique to substitute for batch and column techniques is described. Lead and cadmium were selected as analyte elements. The housing of a syringe mountable membrane filter was filled with Purolite C-100 E cationic resin and mounted to the tip of a plastic syringe. If the sample solution was drawn into the syringe in about 30 s passing through the resin and discharged again for the same length of time, the analyte elements were quantitatively retained at pH ≥ 2. The elements sorbed by the resin were then quantitatively eluted by drawing and discharging 2.5 M HCl as eluent, again at the same flow rates as those used in retention. The recoveries of Pb and Cd were 98.2 and 99%, respectively, with relative standard deviations of around ± 2%. Detection limits (3δ) were 15 µgL−1 for Pb and 10 µgL−1 for Cd. The elements could be concentrated by drawing and discharging several portions of sample successively but eluting only once. Pb and Cd in spiked waste water were recovered quantitatively (>95) with low RSD values of around ±2%. The method proposed is cheaper, simpler, faster and more practical than the column technique. The recoveries and reproducibilities of the method are at the same level as those of the column technique.

Starch coated titanium dioxide nanoparticles as a challenging sorbent to separate and preconcentrate some heavy metals using graphite furnace atomic absorption spectrometry

ABSTRACT In this study, a challenging nanosorbent was described for preconcentration/separation method based on the sorption of cadmium, cobalt, copper, nickel, lead on starch coated titanium dioxide nanoparticles and its analysis by graphite furnace atomic absorption spectrometry. Optimum conditions were investigated for quantitative sorption. By using the proposed technique, the analyte elements were determined in spiked tap-water samples in the range of 95% confidence level. Limit of detection (3δ) was 0.05, 0.28, 1.90, 3.10 and 0.11 µg/L (3σ, N = 10) for cadmium, cobalt, copper, nickel and lead, respectively. The optimised technique is fast, easy handled, simple and environmental friendly.

Elemental Analysis of Tarhana by Microwave Induced Plasma Atomic Emission Spectrometry

ABSTRACT Elemental analysis of tarhana, a traditional Turkish cereal soup, has been conducted. A new method was developed for the determination of calcium, iron, magnesium, manganese, potassium, and sodium, in tarhana by microwave induced plasma atomic emission spectrometry. A sample of 0.1 g were mineralized by microwave digestion in 10 mL of 65% HNO3. A wheat flour standard reference material (GBW 08503) was used for validation. Linear calibration using standards prepared in acid was conducted for all determinations. The limits of detection were 1.21 µg g−1 for Ca at 393.366 nm, 0.43 µg g−1 for Fe at 259.940 nm, 11.5 µg g−1 for K at 766.491 nm, 0.12 µg g−1 for Mg at 285.213 nm, 0.04 µg g−1 for Mn at 403.076 nm, and 0.04 µg g−1 for Na at 588.995 nm. Ca, K, Fe, Mg, Mn, and Na were determined in tarhana with values from 0.73 to 1.61, 0.016 to 0.061, 2.02 to 4.09, 0.473 to 1.414, 0.019 to 0.043, and 0.26 to 1.83 mg g−1, respectively.