Wiesław Wasiak

Hair analysis. Part 1: Differential pulse anodic stripping voltammetric determination of lead, cadmium, zinc and copper in human hair samples of persons in permanent contact with a polluted workplace environment

Prior to determination of Pb, Cd, Zn and Cu by differential pulse anodic stripping voltammetry microwave digestion has been evaluated for the decomposition of human hair samples using a HNO3H2O2 mixture. The efficiency of the decomposition, and the accuracy and precision of the proposed procedure was studied using a human hair standard. Hair samples were collected from the vertex of the scalps of donors who were employed in factories manufacturing lead-acid batteries, nickel-cadmium batteries and gas (petroleum) vending station workers. The results show that, in all cases, permanent contact with the polluted environment makes it possible to absorb very large amounts of lead or cadmium, simultaneously depressing zinc absorption. Results of a study on the content of the above elements in human hair of persons who had had no work place contact with these elements are also presented.

Hair analysis. Part 2. Differential pulse anodic stripping voltammetric determination of thallium in human hair samples of persons in permanent contact with lead in their workplace

Abstract The determination of thallium in human hair samples by differential pulse anodic stripping voltammetry after microwave digestion has been presented. Hair samples were collected from the vertex of the scalps of donors who were employed in factories manufacturing lead-acid batteries. The results show that permanent contact with an environment polluted by lead makes it possible to absorb very large amounts of thallium, which is present in this environment only as an impurity of lead. The study also shows that absorption of thallium by workers is a few times ‘better’ than that of lead.

Iminoketonate complexes of Cu(II) chemically bonded to silica in gas chromatography

Abstract Complexes of Cu(II) chemically bonded to silica surface are studied and used in gas chromatography. Copper(II) chloride in a tetrahydrofuran solution was bonded to the support via iminoketonate groups. The packing obtained in such a way was investigated to evaluate its usefulness in the analysis of aliphatic and aromatic halogenated hydrocarbons as well as ethers and thioethers. A number of retention parameters was determined (retention factor – k , specific retention volume – V g , molecular retention index – Δ M e ) which enabled to characterize specific interactions between bonded metal and adsorbate molecules. A packing containing no bonded metal was also investigated and served as a reference. Attempts were also made to separate some mixtures of the nucleophilic compounds.

Chemically modified silica gel for selective solid-phase extraction and preconcentration of heavy metal ions

This paper describes our research on the synthesis of the sorbent with chemically bonded ketoimine groups, and, furthermore, using this sorbent in the SPE technique to extract and preconcentrate trace amounts of metal ions in water samples. Surface characteristics of the sorbent were determined by elemental analysis, NMR spectra for the solid phases (29Si CP MAS NMR), and analysis of pore size distribution of the sorbent and nitrogen adsorption-desorption. The newly proposed sorbent with ketoimine groups was applied for the extraction and preconcentration of trace amounts of Cu (II), Cr (III) and Zn (II) ions from the water from a lake, post-industrial water and purified water unburdened back to the lake. The determination of the transition-metal ions was performed on an emission spectroscope with inductively coupled plasma ICP-OES. For the batch method, the optimum pH range for Cu (II) and Cr (III) extraction was equal to 5, and Zn(II)–to 8. All the metal ions can be desorbed from SPE columns with 10 mL of 0.5 mol HNO3. The detection limits of the method were found to be 0.7 µg L−1 for Cu (II), 0.08 µg L−1 for Cr (III), and 0.2 µg L−1 for Zn (II), respectively.

Recent advances in gas chromatography for solid and liquid stationary phases containing metal ions

This review is devoted to the application of metal complexes as column packings and liquid stationary phases in gas chromatography. Particular attention is paid to the stationary phases with nitrogen-containing functional groups (e.g., amine and ketoimine) and beta-diketonates on the modified silica surface. The review also concerns the results of the research on metallomesogenes and chiral stationary phases. The factors influencing the retention mechanism in complexation gas chromatography are discussed. Practical application of the metal chelate-containing chromatographic packings for analytical separation of organic substances is considered.

Ketoimino groups as silica surface modifiers

The presented work is devoted to Porasil C silica, with organic compounds bonded to its surface and capable of electron-donor-acceptor (EDA) interactions. These packings are a good base for studying interactions among stationary phases and the adsorbate molecules showing electron-donor properties. The presented work concentrates on the phases containing ketoimino groups at their surface. Copper and chromium chlorides were bonded through these to the surface. Physicochemical characteristics of the obtained packings were determined by the use of elemental analysis, differential scanning calorimetry (DSC) and inverse gas chromatography. We examined the influence of the surface modification on the retention parameters of the nucleophilic compounds.

Chemically bonded chelates as selective complexing sorbents for gas chromatography IV. Silica surfaces modified with Co(II) and Ni(II) complexes

The synthesis of some new packings for complexation gas chromatography (CGC) is proposed in this article. These packings contain acetylacetonates and hexafluoroacetylacetonates of nickel(II) and cobalt(II), which are chemically bonded to a silica gel via β-diketonate groups. The effect of the structure and the configuration of some adsorbates (olefins, cyclic and aromatic hydrocarbons) on the retention of these compounds is determined. Moreover, the usefulness of the packings in the analysis of hydrocarbons is described. The results show the good applicability of the tested packings as well as their high selectivity towards compounds which contain π-electrons.

Chemically bonded chelates as selective complexing sorbents for gas chromatography: II. Ketones, ethers and nitroalkanes

Abstract Specific interactions of ketones, ethers and nitroalkanes with Cu(II) and Ni(II) acetyloacetonates chemically bonded to silica surfaces were investigat

Gas chromatography silica packings with chemically bonded complexes of Cu(II) and Cr(III)

In the presented work, copper(II) and chromium(III) complexes chemically bonded to silica surface were prepared and used in gas chromatography. Chlorides of these metals were bonded to the silica surface by the use of the ketoimine group originally from 2-(3-triethoxysililpropylimino)-3-(n-butyl)-pentanone-4. Packings obtained in such way were investigated to evaluate their usefulness in the analysis of aliphatic and aromatic halogenated hydrocarbons as well as ethers, thioethers and ketones. Moreover, packings were subjected to elemental analysis and differential scanning calorimetry (DSC), thus some retention parameters were determined to characterize specific interactions between bonded metal and adsorbate molecules. Attempts were also made to separate some mixtures of the nucleophilic compounds.

Chemically bonded chelates as selective complexing sorbents for gas chromatography: VI. Modification of silica with NiCl2 and CoCl2 via β-diketonate groups

Results are presented of studies of new types of packings for gas chromatography which contain nickel(II) and cobalt(II) chlorides and nickel(II) acetylacetonate chemically bonded via β-diketonate groups to a silica surface. Taking into account the ability of the metals in the chlorides and acetylacetonate to interact with compounds showing electron-donor properties, the study was performed using such adsorbates as aliphatic linear and branched hydrocarbons. The study allowed the determination of the influence of structure and configuration of adsorbate molecules on their retention and the definition of the usefulness of thus prepared packings in chromatographic analysis. The obtained results point to selectivity of the packings to the compounds which contain π electrons. Moreover, to determine the influence of the type of functional group bonded with hydrocarbon chain of a given silane on charge-transfer interactions, the obtained results were compared with those for the packings in which nickel(II), cobalt(II) chlorides and nickel(II) acetylacetonate were bonded with silica via diphenylphosphine groups.