Sylwia Studzińska

Study of toxicity of imidazolium ionic liquids to watercress (Lepidium sativum L.)

AbstractThe sensitivity of Lepidium sativum L. germination to three imidazolium ionic liquids was investigated in solutions and soils artificially contaminated with mixtures of those compounds. In case of aquatic solutions, the toxic character of analyzed compounds is connected with their hydrophobicity. The seedling growth is increasing with the decrease in ionic liquid hydrophobicity. The novelty of those studies is the application of high-performance liquid chromatography, which was used for the determination of ionic liquid quantity absorbed by cress. There was almost linear relationship between decrease in root germination and amount of ionic liquid uptaken by cress. Furthermore, the systematic studies on the influence of total organic carbon content in soil on the toxicity of ionic liquids to cress were performed for the first time. Hazardous effects appeared to be closely connected with organic matter: with the decrease of total organic carbon quantity, the inhibition of plant growth was more significant. Visual effects of ionic liquid toxic activity to garden cress are similar as in the case of nutrient deficit in plants. FigureVisual phytotoxicity effects observed during the test; leaf chromatosis: light green and yellow (up photos), violet (lower photos)

Study of sorption kinetics of some ionic liquids on different soil types

In the present contribution sorption kinetics experiments under static conditions were utilized in three selected ionic liquids cations (1-ethyl-3-methylimidazolium, 1-butyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium chlorides) study with five type of soil, differing in total organic carbon (TOC) content. The experimental results indicate the sorption capacity growth with increase in TOC content and hydrophobicity of ionic liquid cation. The obtained kinetic sorption parameters as well as distribution coefficients (K(d)) were used to estimate the sorption properties of the soil types towards the ionic liquids in question. The Gibbs free energy values indicate that ionic liquid cations sorption on soils could be generally considered as a physical adsorption with exothermic effect. But the values of -dG for studied cations sorption on soil with very high of TOC content in soil (45%) may testify to nature of chemical adsorption. Sorption of the analyzed compounds occurs probably by means of hydrogen bonds, electrostatic and pi three dots pi interaction with the organic matter and the clay minerals of the soils.

Study of ionic liquid cations transport in soil

Ionic liquids are a form of organic or inorganic molten salts consisting positive and negative ions. There have been several attempts of their utilization in industry. These substances can be released from industrial sites into water and soils thus causing contamination. The most significant chemical processes affecting the behavior of ionic liquid cations in soils are related to their transport. The major aim of this work was to investigate the transport process of imidazolium ionic liquids in soils by column leaching experiments. Five types of soil with varying total organic carbon (TOC) content (<0.1%, 0.5%, 4%, 9.9%, 44.8%), were utilized in the study of transportation of three ionic liquid chlorides namely: 1-ethyl-3-methylimidazolium (EMIM), 1-n-butyl-3-methylimidazolium (BMIM), 1-n-hexyl-3-methylimidazolium (HMIM). The results obtained indicated significant ability to immobilize ionic liquid cations by soils with higher organic carbon content. The higher TOC value in soil results in lower amounts of solutes migrating through the soil. Factorial regression has been applied to modeling of the results. It relates soil and the ionic liquid cation properties to the retardation of this cation in soil profile.

Functionalized anion exchange stationary phase for separation of anionic compounds.

Synthesis of the multilayered stationary phases containing quaternary ammonium functional groups on the silica support was described. Bonded phases were characterized by elemental analysis, solid state (13)C NMR spectroscopy and chromatographic methods. The surface of silica support was coated with different number of polymeric layers formed by condensation polymerization of primary amine (methylamine) with diepoxide (1,4-butanedioldiglycidyl ether). A series of stationary phases with different number of polymerized layers were tested. Separation of an inorganic anions sample (F(-), Cl(-), NO2(-), Br(-), NO3(-)) and nucleotides was performed.

Corona-Charged Aerosol Detection: An Analytical Approach

An alternative to other universal detection methods like refractive index (RI), low wavelength or ultraviolet (UV), and evaporative light scattering detection (ELSD), chemiluminescent nitrogen detection is a relatively new method based upon aerosol charging and involves Corona-charged aerosol detection (Corona-CAD). Some reports show that the sensitivity of this method is lower than that of fluorescence detection. Others confirm approximately five times higher sensitivity than conventional UV absorbance detection for selected analytes. This is the reason that Corona-CAD can be widely used for the determination of nonvolatile or semivolatile compounds, including: lipids, oligosaccharides, carbohydrates, proteins, steroids, surfactants, polymers, peptides, and others. The response of Corona-CAD is independent of chemical properties of the analyte. This article reviews applications of Corona-CAD and principles of the aerosol charging method as well as advantages and disadvantages of the method. The modern solution using an ultra detector, which brings charged aerosol detection to UHPLC, is also discussed.

Effect of mobile phase pH on the retention of nucleotides on different stationary phases for high-performance liquid chromatography.

The main aim of the present investigation was to study the retention and separation of eight nucleotides with the use of seven stationary phases in RP HPLC mode. Two octadecyl columns were used; however, aminopropyl, alkylamide, cholesterol, alkyl-phosphate, and phenyl were also studied. Special attention was paid to the mobile phase buffer pH, since it appears that this factor is very influential in the case of chromatographic separation of nucleotides. The retention of nucleotides was greater for mobile phase pH 4.0 in comparison with pH 7.0 (except for octadecyl and phenyl packing). This is a consequence of protonization of polar groups present on the stationary phase surface. It was proved that aminopropyl, alkyl phosphate, alkylamide packing materials are not suitable for the resolution of nucleotides. On the other hand, cholesterol and phenyl stationary phases are alternatives for conventional octadecyl phases. Application of cholesterol packing allows separation of small, polar nucleotides, which is impossible to achieve in the case of octadecyl phase. Moreover, a phenyl support allows separation of nucleotides in a shorter time in comparison with octadecyl packing.

Study of retention mechanism of imidazolium-based ionic liquids in HPLC.

Retention mechanism of ionic compounds is still not fully known and investigated. It concerns especially ionic liquids (ILs) and HPLC. In the present study, interactions between imidazolium ILs and stationary phases were investigated in complex manner. For that purpose, five ILs, eight packing materials (with different functional groups bonded to silica surface) and three different pH of mobile phases were chosen. A great variety of applied chromatographic columns, as well as the changes made in mobile phase, allows for the description of retention mechanism. The main interactions responsible for retention process appear to be electrostatic, pi-pi and hydrophobic. Such complex results are presented for the first time.

Study of the Interactions of Ionic Liquids in IC by QSRR

The nature of ionic liquids (ILs) facilitates their analysis by ion chromatography which, unlike conventional high-performance liquid chromatography, enables analysis both of cations and anions. This paper describes a pioneering ion-chromatographic investigation of IL cations and statistical evaluation of quantitative structure–retention relationships with the objective of predicting the molecular mechanism responsible for retention. Eleven ionic liquid imidazolium and pyridinium cations were analyzed on a CS15 cation-exchange column by isocratic elution with acetonitrile–methanesulfonic acid mixtures. Structural descriptors of the cations obtained from molecular modeling were used to describe their hydrophobicity as determined by chromatography. The most statistically significant were three-term QSRR regression equations relating log kw to analyte n-octanol–water partition coefficient (log P), dipole moment (μ), solvent accessible surface area (ASAS), and hydration energy (HE). They indicate the important role of both hydrophobic and polar the retention of ILs on the CS15 column.

Fast method for the resolution and determination of sex steroids in urine

The main aim of the study was to develop a simple, fast, sensitive and inexpensive method for the separation and quantification of various steroid hormones in urine. Ultra high performance liquid chromatography was used to analyze estrone, estriol, 17-α-estradiol, 17-β-estradiol, progesterone, pregnenolone, and testosterone. Three columns were chosen for the present study: two octadecyl columns and one octyl column. The best results of separation were obtained for the octadecyl columns. Complete separation of all sex steroids was impossible when methanol was used during the chromatographic studies. The most interesting and valuable result was obtained with regard to the complete separation of isomers. All seven steroids were successfully separated in 10min, next the time of single analysis was reduced to 5.5min with gradient elution. Linearity was evaluated over a range of concentrations of 0.08-12.11ngml(-1). The correlation coefficient ranged from 0.9987 to 0.9998. The LOD values were between 0.02 and 0.33ngml(-1) and LOQ ranged between 0.10 and 1.10ngml(-1). The developed method is suitable for routine analysis of these compounds in urine.

A new way to fast and high resolution determination of modified nucleosides

The abnormal concentration of several modified nucleosides in the urine is supposed to be marker of carcinogenesis. For this reason analytical methods useful in the determination of these compounds in biological samples are of great importance. Present study concerns the application of Ultra High Performance Liquid Chromatography for fast, precise, high resolution separation and quantification of eight modified nucleosides in the synthetic serum and urine samples. The systematic study concerning the retention behavior of analyzed nucleosides on various stationary and mobile phases was performed. The attempt to apply four different column packings (octedecyl, octyl, phenyl, siliga gel) of different particle sizes and various mobile phases was made. On the basis of obtained results Kinetex C18 column and methanol/water mixtures were chosen for the utilization in biological samples. Developed method allows separation and quantification of eight modified nucleosides in serum or urine during 4min with good linearity, accuracy and low LOQ values.