Beata Godlewska-Żyłkiewicz

Biosorption of platinum and palladium for their separation/preconcentration prior to graphite furnace atomic absorption spectrometric determination☆

Inexpensive bakers yeast Saccharomyces cerevisiae and green algae Chlorella vulgaris, either free or immobilized on silica gel have been shown to selectively accumulate platinum and palladium from water samples in acidic medium (pH 1.6–1.8). Optimization of conditions of metals biosorption (sample pH, algae and yeast masses, adsorption time, temperature) was performed in batch mode. The procedure of matrix separation based on biosorption of platinum and palladium on algae C. vulgaris covalently immobilized on silica gel in flow mode was developed. The use of algae in flow procedure offers several advantages compared with its use in the batch mode. The procedure shows better reproducibility (<2%), improved efficiency of platinum retention on the column (93.3±1.6%), is less laborious and less time consuming. The best recovery of biosorbed metals from column (87.7±3.3% for platinum and 96.8±1.1 for palladium) was obtained with solution of 0.3 mol l−1 thiourea in 1 mol l−1 hydrochloric acid. The influence of thiourea on analytical signals of examined metals during GFAAS determination is discussed. The procedure has been applied for separation of noble metals from tap and waste water samples spiked with platinum and palladium.

Ion-Exchange Preconcentration and Separation of Trace mounts of Platinum and Palladium

ABSTRACT The preconcentration and separation of platinum and palladium from weakly acidic solution (pH=4) were done on microcolumn packed with Cellex-T resin. Selective platinum elution from the column was performed with 0.01 mol/l glycine solution at pH=12, while for palladium elution 1.2 mol/l thiourea (pH=0.5) or 4.0 mol/l potassium thiocyanate (pH=1) may be used. As the detection technique was used either FAAS or GFAAS, depending on the concentration of studied metals in the eluate.

The Use of Algae Chlorella vulgaris Immobilized on Cellex‐T Support for Separation/Preconcentration of Trace Amounts of Platinum and Palladium before GFAAS Determination

Abstract The ability of green algae Chlorella vulgaris, immobilized on Cellex‐T support, for selective binding of platinum (Pt) and palladium (Pd) from acidic solutions (at pH range 1.5–1.8) has been demonstrated. The use of immobilized algae packed into a microcolumn (150 mg) in a flow mode provides good efficiency and reproducibility of the biosorption process (95.2 ± 0.4% for Pt and 99.3 ± 0.9% for Pd). The presence of seven interfering ions up to their 100 µg mL−1 concentration does not influence Pt and Pd retention on the column. The best efficiency of elution for both metals from the column was obtained with 0.3 mol L−1 thiourea (TU) in 1 mol L−1 hydrochloric acid used as a stripping reagent The detection limits obtained by the optimized method, followed by graphite furnace atomic absorption spectrometric detection for Pt and Pd, were 0.2 and 0.096 ng mL−1, respectively. The proposed method was applied for matrix separation and determination of Pt and Pd by graphite furnace atomic absorption spectrometry (GFAAS) in spiked tap water, wastewater, and grass samples.

Analytical Applications of Living Organisms for Preconcentration of Trace Metals and Their Speciation

Living organisms, naturally occurring in human environment, gained in the last decade, increasing interest in analytical chemistry. This review presents the application of bacteria, yeast, algae, and fungi for the preconcentration of heavy metals from environmental samples. The specific bonding sites on cell walls are responsible for the selective binding of different species of studied metals that permit the use of them as sorbents for speciation analysis purposes.

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 flow-injection method for the determination of Pt(IV) in environmental samples based on chemiluminescence reaction of lucigenin and biosorption.

A new flow-injection chemiluminescence method (FI-CL) was developed for the determination of trace amounts of Pt(IV). The method is based on the quenching effect of the analyte on CL emission generated by lucigenin in alkaline solution. Application of a column filled with an algae Chlorella vulgaris immobilized on Cellex-T resin allowed to preconcentrate and separate the Pt(IV) ions from complex environmental samples, such as road dust. The developed method is simple and does not require sophisticated instrumentation. It is also characterized by a very low limit of detection (0.1ngmL(-1)), good sensitivity and precision (RSD<3%). The accuracy of the presented method was confirmed by analysis of a certified reference material of tunnel dust (BCR-723). The content of Pt in road dust samples collected in Białystok (Poland) in 2009 determined by the evaluated method was 351.8+/-54.6ngg(-1) and was higher than in samples collected in years 2000 and 2003.

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.

Evaluation of ion imprinted polymers for the solid phase extraction and electrothermal atomic absorption spectrometric determination of palladium in environmental samples

The complexes of Pd(II) with ammonium pyrrolidinedithiocarbamate (APDC), N,N′-diethylthiourea (DET) and dimethylglyoxime (DMG) were prepared and imprinted into a polymeric network. The ion-imprinted polymers (IIPs) were synthesized by copolymerization of 4-vinylpyridine (VP) and styrene as functional monomers and divinylbenzene as a cross-linking agent in the presence of 2,2-azo-bis-isobutyronitrile as an initiator. The influence of sample volume, pH and flow rate on the extraction efficiency of Pd was studied under dynamic conditions. Pd(II) could be quantitatively retained on each of the studied sorbents at the pH range of 0.5 to 1.0, and eluted with an acidic solution of thiourea. The polymer with the imprinted Pd-DET-VP complex offered the highest selectivity for Pd(II) over certain matrix components, such as Pt(IV), Ni(II) and Cu(II). The low sample pH is an important advantage of the separation procedure, as it allows an effective separation of Pd(II) from complex environmental matrices. The developed separation method was successfully applied to the electrothermal atomic absorption spectrometric (ETAAS) determination of trace amounts of Pd in tap and river water, grass, and certified platinum ore (CRM SARM 7 and SARM 76) samples with reproducibility below 6.5%. The detection limit for Pd(II) obtained by ETAAS after the pre-concentration on Pd-DET-VP polymer was 0.012 ng mL−1 for 75 mL sample volume.

Recent Advances in On-Line Methods Based on Extraction for Speciation Analysis of Chromium in Environmental Matrices.

The biological activity of Cr(III) and Cr(VI) species, their chemical behavior, and toxic effects are dissimilar. The speciation analysis of Cr(III) and Cr(VI) in environmental matrices is then of great importance and much research has been devoted to this area. This review presents recent developments in on-line speciation analysis of chromium in such samples. Flow systems have proved to be excellent tools for automation of sample pretreatment, separation/preconcentration of chromium species, and their detection by various instrumental techniques. Analytical strategies used in chromium speciation analysis discussed in this review are divided into categories based on selective extraction/separation of chromium species on solid sorbents and liquid-liquid extraction of chromium species. The most popular strategy is that based on solid-phase extraction. Therefore, this review shows the potential of novel materials designed and used for selective binding of chromium species. The progress in miniaturization of measurement systems is also presented.