Elżbieta Zambrzycka

Separation of ruthenium from environmental samples on polymeric sorbent based on imprinted Ru(III)-allyl acetoacetate complex

A new ion imprinted polymer (IIP) for ruthenium recognition/pre-concentration was prepared via bulk polymerization using methacrylic acid as the functional monomer and ethylene glycol dimethacrylate as the cross-linking agent in the presence of Ru(III)-allyl acetoacetate complex as a template. The synthesized IIP was used as a new support for solid phase extraction (SPE) of ruthenium from environmental samples before electrothermal atomic absorption spectrometric determination. Variables affecting the SPE process, such as pH, load and elution flow rates, as well as concentration and volume of the eluting solution, were evaluated. The optimized procedure consists of a sample loading (sample pH of 6.5 ± 0.5) through IIP-SPE columns containing 200mg of the synthesized IIP at a flow rate of 1.0 mL min(-1). Elution was performed by passing 0.3 mol L(-1) thiourea in 0.1 mol L(-1) HCl at a flow rate of 1.0 mL min(-1). For 10 mL of sample pre-concentration factor of 20 was achieved. The limit of detection of the method was 0.32 ng mL(-1), while the relative standard deviation for six replicated separation processes was 2.5%. Good selectivity of the synthesized material for Ru(III) ions against other transition metal ions assures efficient removal of matrix of analyzed samples (tap and river water, municipal and road sewages, and grass) by the proposed IIP-SPE procedure.

Multi-commutation flow system with on-line solid phase extraction exploiting the ion-imprinted polymer and FAAS detection for chromium speciation analysis in sewage samples

A multi-commutation flow analysis system using on-line solid phase extraction and flame atomic absorption spectrometric detection (MCFA-FAAS) was developed for the study of chromium speciation in sewage samples. A new chromium imprinted polymer was prepared and applied as a selective sorbent for the separation and preconcentration of Cr(III) ions. The polymer was prepared using a Cr(III)-8-hydroxyquinoline complex as a template, styrene as a functional monomer, and divinylbenzene as a crosslinking monomer using 2,2′- azobisisobutyronitrile as an radical initiator for bulk polymerization. The chromium imprinted polymer exhibits good chemical and mechanical stability, sorption capacity and selectivity towards Cr(III) ions. The analyte, Cr(III) ions, was quantitatively retained on the sorbent at pH 9, eluted with 0.3 mL of 0.1 mol L−1 nitric acid and determined by FAAS with a detection limit of 2.1 ng mL−1 and a 33-fold preconcentration factor obtained with a 10 min loading time. The MCFA-FAAS system is fully automated and enables analysis of 1 mL of sample in 4.5 min, which gives a throughput of 12 samples per hour. The accuracy of the proposed method was proved by analysis of a reference material of wastewater RES 10.2 (ielab). The method was successfully applied to the determination of trace amounts of Cr(III) in municipal sewage samples.

A novel ion imprinted polymer as a highly selective sorbent for separation of ruthenium ions from environmental samples

A complex of Ru(III) with benzaldehyde thiosemicarbazone was used for the preparation of new ruthenium ion imprinted polymers. The polymers were synthesized using 4-vinylpyridine and styrene as functional monomers, divinylbenzene as a cross-linking agent, and ethanol or chloroform as a porogen in the presence of 2,2′-azobisisobutyronitrile as an initiator via the bulk polymerization technique. The polymers were used in dynamic mode as a selective sorbent for solid phase extraction of Ru(III) ions. The analyte was efficiently retained on the polymers at pH 8.0 ± 0.1 and eluted with 2 mL of 0.3 mol L−1 thiourea in 0.3 mol L−1 HCl. The influence of the type of porogen (ethanol and chloroform) and column size on the separation of analyte on the prepared material was also studied. The efficiency of retention and elution and sample flow rates were higher on columns of smaller diameter and the polymer prepared in ethanol. The analytical performance of the polymer prepared in ethanol such as the recovery of the Ru(III) ions, the reproducibility of the results (<3%), the limit of detection (0.26 ng mL−1), the selectivity in the presence of Pt(IV), Pd(II), Rh(III), Co(II) ions and the sorption capacity (237.4 μg g−1) was superior in comparison to other ruthenium imprinted polymers. The developed separation procedure was successfully applied to electrothermal atomic absorption spectrometric determination of trace amounts of ruthenium in tap and river water, municipal sewage, road runoff, and grass.

Stability of core-shell magnetite nanoparticles.

In the paper, we present three different types of magnetite nanoparticles which were prepared from co-percipitation of iron (II) and (III) chlorides in aqueous solution with and without SiO2 and from thermal decomposition of iron (III) acetylacetonate in nonaqeous solutions. The obtained core-shell nanoparticles were tested in respect of their stability in distilled water, 10% acetic acid, 0.01 M citric acid, 0.9% NaCl and commercial white wine (12% of alcohol). Changes of the nanoparticles were examined by infrared spectroscopy, atomic absorption spectroscopy, transmission electron microscopy, X-ray diffraction and differential scanning calorimetry methods. Modification of magnetic properties was measured by Mössbauer spectroscopy.