Suleyman Akman

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.

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.

Determination of lead, copper and manganese by graphite furnace atomic absorption spectrometry after separation/concentration using a water-soluble polymer

In this study, a water-soluble polymer, polyvinylpyrrolidinone (PVP) having chelating functionalities was used for the preconcentration and separation of traces of Pb, Cu, Ve and Mn prior to their determination by graphite furnace atomic absorption spectrometry. For this purpose, the sample and the PVP solutions were mixed and the metal bound polymer was precipitated by adding the mixture onto acetone. The precipitate was separated by decantation and dissolved with water. By increasing the ratio of the volumes of sample to water used in dissolving the precipitate, the analyte elements were concentrated as needed. The concentration of trace elements was determined using graphite furnace atomic absorption spectrometry. The analyte elements in matrix free aqueous solutions were quantitatively recovered. The validity of the proposed method was checked with a standard reference material (NIST SRM 1577b bovine liver) and spiked fruit juice, sea water and mineral water samples. The analytical results were found to be in good agreement with certified and added values. Detection limits (3delta) were 1.7, 3.6 and 4.1mugl(-1) for Pb, Cu and Mn, respectively, using 10mul of sample volume. The method is novel and can be characterized by rapidity, simplicity, quantitative recovery and high reproducibility.

Method development for the determination of fluorine in toothpaste via molecular absorption of aluminum mono fluoride using a high-resolution continuum source nitrous oxide/acetylene flame atomic absorption spectrophotometer.

Fluorine was determined via the rotational molecular absorption line of aluminum mono fluoride (AlF) generated in C(2)H(2)/N(2)O flame at 227.4613 nm using a high-resolution continuum source flame atomic absorption spectrophotometer (HR-CS-FAAS). The effects of AlF wavelength, burner height, fuel rate (C(2)H(2)/N(2)O) and amount of Al on the accuracy, precision and sensitivity were investigated and optimized. The Al-F absorption band at 227.4613 nm was found to be the most suitable analytical line with respect to sensitivity and spectral interferences. Maximum sensitivity and a good linearity were obtained in acetylene-nitrous oxide flame at a flow rate of 210 L h(-1) and a burner height of 8mm using 3000 mg L(-1) of Al for 10-1000 mg L(-1)of F. The accuracy and precision of the method were tested by analyzing spiked samples and waste water certified reference material. The results were in good agreement with the certified and spiked amounts as well as the precision of several days during this study was satisfactory (RSD<10%). The limit of detection and characteristic concentration of the method were 5.5 mg L(-1) and 72.8 mg L(-1), respectively. Finally, the fluorine concentrations in several toothpaste samples were determined. The results found and given by the producers were not significantly different. The method was simple, fast, accurate and sensitive.

Investigations of interferences in graphite furnace atomic absorption spectrometry using a dual-cavity platform. Part 2. Influence of sodium chloride and nickel chloride on the atomisation of lead

The interferences from sodium and nickel chlorides on the determination of lead which occur in the absence of a modifier are not due to gas-phase interactions. Some lead chloride is lost in the form of gaseous molecules at temperatures above 500 °C. In the presence of nickel chloride, lead is lost primarily by co-volatilisation with the hydrogen chloride gas, which is generated by the decomposition of the salt. Expulsion of the analyte by matrix vapours was found to be a source of interference with both of the chlorides investigated. Nitric acid had no influence on the interference from sodium chloride but reduced the interference from nickel chloride. The stabilising effect found on the addition of both nitric acid and nickel chloride was due to nickel only. Various interactions between the gas phase and the condensed phase were observed when analyte and interferent were separated on the dual-cavity platform. The determination of lead in the presence of sodium or nickel chlorides was free from interferences when ammonium phosphate-magnesium nitrate was added as a modifier.

A practical method for the determination of sulphur in coal samples by high-resolution continuum source flame atomic absorption spectrometry

Sulphur in coal was determined using a high-resolution continuum source flame atomic absorption spectrophotometer (HR-CS-FAAS) with actylene/air flame. The C-S absorption band at 258.056 nm was found the most suitable analytical line with respect to sensitivity and spectral interferences. The instrumental parameters were optimized. The coal samples were dried and dissolved using microwave-assisted digestion technique. The validity of the method was tested using standard reference material and certified values were found in the limits of 95% confidence level. Since the concentrations of matrix elements of coal other than carbon are low enough not to cause any spectral interferences, the linear calibration method was applied in all quantifications without any problem. The calibration standards were prepared in sulphuric acid. The method was accurate, fast, simple and sensitive. The limit of detection (LOD, 3δ, N=10) and the limit of quantification (LOQ, 10δ, N=10) were found to be 0.01 and 0.03% (w/w), respectively. The sulphur concentrations of various kinds of the coal samples received around Turkey were determined. The sulphur contents of the coal samples were ranged from ≤ LOQ to 1.2%.

Sorption and preconcentration of copper and cadmium on silica gel modified with 3-aminopropyltriethoxysilane

Summary3-Aminopropyltriethoxysilane, (C2H5O)3 Si(CH2)3NH2, loaded on silica gel was used as a pre-concentration sorbent for copper and cadmium prior to their determination by flame atomic absorption spectrometry (FAAS). Both batch and column methods were used for the separation of the above metals. The analytes are quantitatively retained on the proposed adsorbent at pH 6.5. The complexation capacity of the collector is 0.032 mmol Cu/g silica. In the batch method, the effects of shaking time and the ratio of metal/silica on the retention by the asorbent were investigated. Columns filled with the collector provided quantitative recovery of the above metals from standardized samples as well as from sodium chloride solutions.

A novel slurry sampling analysis of lead in different water samples by electrothermal atomic absorption spectrometry after coprecipitated with cobalt/pyrrolidine dithiocarbamate complex

A preconcentration/separation technique based on the coprecipitation of lead with cobalt/pyrrolidine dithiocarbamate complex (Co(PDC)(2)) and subsequently its direct slurry sampling determination by electrothermal atomic absorption spectrometry (AAS) was described. For this purpose, at first, lead was coprecipitated with cobalt/pyrrolidine dithiocarbamate complex formed using ammonium pyrrolidine dithiocarbamate (APDC) as a chelating agent and cobalt as a carrier element. The supernatant was then separated and the slurry of the precipitate prepared in Triton X-100 was directly analyzed by electrothermal atomic absorption spectrometry with respect to lead concentration. The effects of experimental conditions on coprecipitation of lead with gathering precipitate as well as homogeneity and stability of the slurry were investigated. After the optimization of experimental parameters, a 100-fold enrichment of the analyte with quantitative recovery (>90%) and high precision (<10% R.S.D.) were obtained. By using the proposed technique, the lead concentrations in heavy matrices of Certified Sea-water and wastewater samples could be practically and rapidly determined in the range of 95% confidence level. The detection limit of the described method for lead using sample-matching blanks was 1.5 ng/L (3 sigma, N=10).

Concentration of cadmium, copper and zinc using water soluble polyacrylic acid polymer

Abstract In this study, a simple method was developed to use water soluble polymer, polyacrylic acid, for the separation and pre-concentration of trace Cd, Cu and Zn prior to their analysis by flame atomic absorption spectrometry. For this purpose, the sample and poly-acrylic acid were mixed and the metal-bound polymer was precipitated by the addition of acetone. The precipitate was separated and dissolved in a minimum amount of water and aspirated into a flame AAS. The method was compared with traditional water insoluble sorbents in all aspects. The technique described is fast, simple, precise and inexpensive. Blank values were low and recoveries were 96.5% for Cd, 99.7% for Cu and 98.0% for Zn. Detection limits (3σ) were 1.8 μg l−1 for Cd, 2.5 μg l−1 for Cu, and 2.2 μg l−1 for Zn.

Determination of total sulfur in food samples by solid sampling high-resolution continuum source graphite furnace molecular absorption spectrometry.

The determination of sulfur in food samples via the rotational molecular absorption of carbon monosulfide (CS) was performed using a solid sampling high-resolution continuum source electrothermal atomic absorption spectrophotometer (SS-HR-CS-ETAAS). In the presence of plenty of carbon in the graphite furnace as well as in food samples, CS was formed in the gas phase without the addition of any molecule forming element externally. The effects of the wavelength selected to detect CS, graphite furnace program, amount of sample, coating of the graphite tube and platform with Ir, and the use of a Pd modifier on the accuracy, precision, and sensitivity were investigated and optimized. Sulfur was determined in an iridium-coated graphite tube/platform at 258.056 nm by applying a pyrolysis temperature of 1000 °C and a molecule forming temperature of 2400 °C. The calibration curve prepared from Na2S was linear between 0.01 μg (LOQ) and 10 μg of S. The accuracy of the method was tested by analyzing certified reference spinach and milk powder samples by applying a linear calibration technique prepared from aqueous standard. The results were in good agreement with certified values. The limit of detection and characteristic mass of the method were 3.5 and 8.1 ng of S, respectively. By applying the optimized parameters, the concentrations of S in onion and garlic samples were determined.