Nilgun Tokman

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.

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.

Determination of lead and nickel in Apple-Leaves and sea-water by electrothermal atomic absorption spectrometry after solid-phase extraction using Chromosorb-107 filled in a syringe.

Lead and nickel were concentrated and separated after sorbing on Chromosorb-107 filled in a syringe prior to their determination by electrothermal atomic absorption spectrometry. To retain the analytes, the sample solution treated with or without ammonium pyrolidine dithiocarbamate (APDC) was drawn into the syringe filled with Chromosorb-107 and discharged back manually. Then the analyte elements were eluted by drawing and discharging the suitable eluent. The optimum experimental conditions for quantitative recoveries of analytes (amount of sorbent, pH of sample, concentration and kind of eluent, flow rates of sample and eluent and adding of the effect of complexing agent) were investigated. Nickel was quantitatively retained at pH6 irrespective of whether it was complexed with APDC while the quantitative sorption of lead was achieved at pH8 only if it was treated with APDC prior to passing through the sorbent. The lead and nickel retained on the sorbent were eluted drawing and discharging 4.5 M HNO(3), respectively. If the concentration of analyte elements in the sample were too low to be detected, then they were concentrated by increasing the ratio of sample value to eluent volume as needed. The lead and nickel in spiked sea-water samples and in certified reference Apple-Leaves (NIST SRM 1515) standards were quantitatively (95%) recovered with R.S.D. of around +/-2%.

The use of solid-phase extraction and direct injection of a copolymer sorbent as slurry into the graphite furnace prior to determination of cadmium by ETAAS

Cadmium in different certified materials was determined by direct injection of sorbent loaded with the analyte into the graphite furnace of electrothermal atomic absorption spectrophotometer. For this purpose, cadmium was collected on ethylene glycol dimethacrylatemethacrylic acid copolymer treated with ammonium pyrolidine dithiocarbamate by the batch technique. After separation of liquid phase, slurry of the sorbent was prepared for the direct injection of the sorbent into graphite furnace. Optimum conditions for quantitative sorption and those for preparing homogeneous and durable slurry were investigated. A 100-fold enrichment factor could be reached. Cadmium in certified sea water and bovine liver samples was determined within the 95% confidence limits. The proposed technique is fast and simple, and the risk of contamination is low. The calculated detection limit for cadmium using sample-matching blanks was 0.09 µg L−1 according to the 3σ concept for the described method.

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.