Iwona Rykowska

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.

Extraction of copper ions using silica gel with chemically modified surface

The applicability of silica gels for the application in solid-phase extraction was tested. Silica was modified with ketoimine groups. Surface characteristics of the modified silica were determined by elemental analysis, NMR spectra of solid phases (29Si CP MAS NMR), analysis of pore size distribution of the silica support, and nitrogen adsorption-desorption. Newly proposed sorbents with ketoimine groups were applied in the preconcentration of trace amounts of the Cu (II) ions from lake water, post-industrial water, and demineralized water unburdened back to the lake.

Retention indices and quantum-chemical descriptors of aromatic compounds on stationary phases with chemically bonded copper complexes.

In this paper, Kováts retention indices determined on stationary phases with chemically bonded copper complexes were correlated with molecular structural parameters for aromatic compounds. Principal component regression (PCR) was applied to extract principal components from the set of 13 descriptors compiled in 5 theoretical models. Extracted components were used to model theoretical retention indices. Significant correlations were found among the retention indices of these compounds and, among others: molecular surface and molecule area, boiling point, HOMO and LUMO energies, dipole moment, dielectric energy, and double bond count. These correlations provide insights into the mechanism of chromatographic retention at the molecular level for the packings and the compounds under study.

Chemically bonded chelates as selective complexing sorbents for gas chromatography. VII. N-[3-(trimethoxysilyl)propyl]diethylenetriamine complexes with CuCl2 and CrCl3

Abstract The study reported in this work concerns the use of copper and chromium complexes, chemically bonded to silica, in gas chromatography. Chlorides of these metals were bonded to the support through amino groups from [3-(trimethoxysilyl)propyl]diethylenetriamine. The packings were tested in order to verify their usefulness in the analysis of aliphatic and aromatic nucleophilic compounds. The retention parameters characterising specific interactions of the bonded metal with adsorbate molecules, such as: retention factor (k), retention index (I), specific retention volume (Vg), and molecular retention index (ΔMe), were determined. For comparison, similar measurements were conditioned on a packing with no bonded metal.

In vitro determination of titanium and other metals released from intra-osseous dental implants into the mucosa

The main goal of the study was to determine the compounds released from titanium into the overlying oral mucosa and the other metals found in two-stage dental intra-osseous implants. The determined concentration of the metals was as follows: titanium from 1.7 to 13.1 μg g−1, nickel 10.0–0.8 μg g−1, aluminum 5.3–100.5 μg g−1, zinc 16.1–118.8 μg g−1, and copper 0.3–13.6 μg g−1, respectively. Additionally, we also present the results of experiments carried out to determine the release of metal ions from two implant systems (Astra and Dentium) into a solution of lactic acid (1%). The quantitative analysis of the metal ions was performed by means of an emission spectroscope by inductively coupled plasma ICP-OES. Studies were also carried out on the surfaces of different implant systems, including: Osteoplant, Astra, Dentium, SKY, Neoss as well as Biomet. The research involved the use of scanning electron microscopy to determine the chemical composition and quality of these systems.

Chemically Bonded Phases for the Analysis of Trace Amounts of Organic Pollutants

ABSTRACT This work describes some results of identification and determination of bisphenol A (BPA) in powdered milk by applying the gas chromatography. To determine BPA contents in the milk and to reduce the matrix interference associated with the constituents of the powdered milk, we performed the following activities. First, we ultra-centrifuged the dissolved milk solutions. Next, we preconcentrated the analyte in the supernatant using a C18 and new sorbent with chemically bonded ketoimine group solid phase extraction column. Finally, we used gas chromatography for the determination of BPA in the samples under study. A recovery of bisphenol A from spiked milk samples was also performed, with recovery result located at 91% ± 3%/94% ± 2%.

SPE and GC methods of preconcentration and determination of phenol, o-chlorophenol, and benzene by means of chemically modified silica

SPE and GC methods of preconcentration and determination of phenol, o-chlorophenol, and benzene by means of chemically modified silica In the paper preparation, characteristics and potential applications of two new sorbents with chemically bonded transition metal complexes have been presented. The sorbents have been synthesized by attaching copper (II) chlorides to the silica surface through ketoimine groups. The suggested application area of the proposed sorbents is related with solid-phase extraction (SPE) of aromatic compounds of different structure, e.g., phenol, 2-chlorophenol, and benzene from water matrix. The experiments proved high efficiency of the sorbents, the ranging recovery rates from 88% to 96% and the LOD values from 0.2 for phenol, and 1.0 for o-chlorophenol. Basic characteristics of the sorbents synthesized were determined by the use of elemental analysis and UV-VIS spectroscopy.

Complexes of transition metals bonded to silica via β -diketonate groups — synthesis, structure, and catalytic activity

Transition metal complexes bonded to silica via silanes with β-diketonate groups can be used as packings for complexation gas chromatography or as immobilized homogenous metal complex catalysts. On basis of elemental analysis and the determination of surface area, possible structures of the complexes formed on the silica surface have been proposed. The possibility of using the immobilized complexes as catalysts has been indicated. Especially nickel complexes were taken into consideration. These immobilized complexes were used previously as packings for complexation gas chromatography.