Agnieszka Zgoła-Grześkowiak

Dispersive liquid–liquid microextraction applied to isolation and concentration of alkylphenols and their short-chained ethoxylates in water samples

Dispersive liquid-liquid microextraction (DLLME) coupled with high-performance liquid chromatography with fluorescence detector was applied for the determination of alkylphenols and their short-chained ethoxylates in water samples. Development of DLLME procedure included optimisation of some important parameters such as kind and volume of extracting and dispersing solvents. Under optimised conditions 50 microL of trichloroethylene in 1.5 mL of acetone were rapidly injected into 5 mL of a water sample. After centrifuging the organic phase containing the analytes was taken for evaporation with a gentle nitrogen purge and reconstituted to 50 microL of acetonitrile. The aliquot of this solution was analysed with the use of HPLC. For octylphenol (OP) and octylphenol ethoxylates (OPEOs) linearity was satisfactory in the range 8-1000 microg L(-1) and for nonylphenol (NP) and nonylphenol ethoxylates (NPEOs) linearity was in the range from 50 to about 3000 microg L(-1). Limit of quantitation was 0.1 microg L(-1) for OP and OPEOs and 0.3 microg L(-1) for NP and NPEOs. Satisfactory recoveries between 66 and 79% were obtained for environmental samples. The results showed that DLLME is a simple, rapid and sensitive analytical method for the preconcentration of trace amounts of alkylphenols and their ethoxylates in environmental water samples.

Differences and dynamic changes in the cell surface properties of three Pseudomonas aeruginosa strains isolated from petroleum-polluted soil as a response to various carbon sources and the external addition of rhamnolipids

Three Pseudomonas aeruginosa strains isolated from petroleum-polluted soil were the subject of studies concerning changes in cell surface properties. Fundamentally different reactions could be observed for each of the studied strains after a cultivation on various carbon sources. The experiments carried out during the logarithmic growth phase showed, that the changes in the cell surface hydrophobocity values were dynamic and substrate dependant. An external addition of rhamnolipids to the tested systems resulted in further shifts in the CSH values. All of the strains displayed miscellaneous phenotypic properties during MATH, sedimentation profile, Zeta potential and surface tension measurements. The obtained results lead to a conclusion, that the presence of rhamnolipids seems to be the key factor to this phenomenon, as all of the studied strains exhibited the ability to produce this biosurfactant in a different degree.

Determination of nonylphenol and short-chained nonylphenol ethoxylates in drain water from an agricultural area.

Water samples from agricultural drains were tested for the presence of nonylphenol and nonylphenol mono- and diethoxylates. The analytes belong to biodegradation products of long-chained nonylphenol ethoxylates, which are used as additives in pesticide formulations. Quantification of these analytes was performed by HPLC with fluorescence detection after isolation by using multi-capillary polytetrafluoroethylene (PTFE) trap extraction. This newly developed technique allowed obtaining about 90% recovery of these analytes in synthetic samples and several percent lower recovery in real samples. Also, no additional sample cleaning was needed before chromatographic analysis. The limit of quantitation for all the analytes was 0.1 microg L(-1). The nonylphenol, nonylphenol mono- and diethoxylates were detected at the concentrations ranging from 0.5 to 6.0 microg L(-1), from 0.2 to 0.7 microg L(-1) and from below 0.02 to 0.4 microg L(-1), respectively. Concentrations of nonylphenol and its derivatives were higher in samples taken in spring than in summer.

In situ metathesis ionic liquid formation dispersive liquid–liquid microextraction for copper determination in water samples by electrothermal atomic absorption spectrometry

In situ synthesis of ionic liquid extractant for dispersive liquid-liquid microextraction (in situ IL DLLME) combined with electrothermal atomic absorption spectrometry (ET AAS) for determination of copper in water samples was developed. Analytical signals were obtained without the back-extraction of copper from the IL phase prior to its determination by AAS. Some essential parameters of the microextraction and detection techniques such as the pH of sample solution, volume of components for in situ synthesis, matrix interferences and main parameters of graphite furnace atomizer have been studied. Under optimal conditions, high extraction efficiency for copper was achieved for the extraction of 0.7 µg L(-1) in 10.0 mL of sample solution employing 8 μL of 1-hexyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide (HmimNTf2) as the extraction solvent. The detection limit was found as 0.004 µg L(-1) with an enrichment factor of 200. The relative standard deviation (RSD) for seven replicate measurements of 0.7 µg L(-1) in sample solution was 4%. The accuracy of the proposed method was evaluated by analysis of the Certified Reference Materials: NIST SRM 2709 (San Joaquin Soil), NBS SRM 2704 (Buffalo River Sediment), NRCC DOLT-2 (Dogfish Liver) and NIST SRM 1643e (Trace Element in Water). The measured copper contents in the reference materials were in satisfactory agreement with the certified values. The method was successfully applied to analysis of the tap, lake and mineral water samples.

Isolation, preconcentration and determination of rhamnolipids in aqueous samples by dispersive liquid-liquid microextraction and liquid chromatography with tandem mass spectrometry.

An analytical method based on liquid chromatography-tandem mass spectrometry (LC-MS-MS) was developed for the determination of rhamnolipids. A dispersive liquid-liquid microextraction (DLLME) procedure was used to isolate and concentrate target compounds from aqueous samples collected from surface water, sewage treatment plant effluent and cultivation of microbial culture. Development of the DLLME procedure included optimization of several important parameters such as kind and volume of extracting and dispersing solvents as well as sample pH. Under optimized conditions a two-step extraction with sonication was used. Chloroform was applied as the extracting and acetone as the dispersing solvent. The recoveries of the analytes were 70-87%. Matrix effects investigated for the analytes revealed existence of ionization enhancement for both mono- and dirhamnolipids.

Analytical methods applied for the characterization and the determination of bioactive compounds in coffee

Coffee, the one of the most popular beverages in the world, contains many bioactive compounds especially caffeine—the natural stimulant and chlorogenic acids with antioxidative properties. Other chemicals such as diterpenes may influence human serum lipids and protect from the risk of some types of cancer. All these compounds are widely determined in Coffea arabica and robusta green and roasted coffee beans, coffee brews and instant coffees to increase food quality standards. The most important analytical methods are reviewed, including these using high-performance liquid chromatography, ultraviolet spectrophotometry and voltammetry techniques, that have been applied to quantify the major bioactive compounds of coffee samples: phenols—inter alia chlorogenic acids and derivatives; methylxanthines—caffeine; trigonelline; nicotinic acid; diterpenes; and short-chain carboxylic acids. Usage of hyphenated techniques such as liquid chromatography–mass spectrometry and gas chromatography–mass spectrometry for identification and determination of coffee constituents is also presented.

Solid-phase extraction combined with dispersive liquid-liquid microextraction, fast derivatisation and high performance liquid chromatography-tandem mass spectrometry analysis for trace determination of short-chained dodecyl alcohol ethoxylates and dodecyl alcohol in environmental water samples.

A new method was developed for preconcentration, derivatisation and analysis of short-chained dodecyl alcohol ethoxylates and dodecyl alcohol. Solid-phase extraction combined with dispersive liquid-liquid microextraction was used for preconcentration of target compounds. Several parameters were optimised including different solid phase extraction sorbents, type and volume of both extracting and dispersive solvents. As a result fast and relatively simple preconcentration method was developed. The analytes were preconcentrated 700 times with the use of small sample volume. The target compounds were derivatised before analysis with the use of newly developed procedure. The derivatisation procedure was made in vial insert and was performed at room temperature with the use of 1-naphthoyl chloride as the derivatisation agent. The developed method was used for the analysis of short-chained dodecyl alcohol ethoxylates and dodecyl alcohol in both sewage effluent from sewage treatment plants and river water samples.

Ionic liquids with dual pesticidal function

Ionic liquids with dual pesticidal function were obtained using cheap, well known and commonly employed fungicides and herbicides. High activity was maintained for both the fungicide (cation) and the herbicide (anion). The obtained salts are novel phytopharmaceuticals, which may be successfully used as an alternative to conventional pesticides.

Modification of surface and enzymatic properties of Achromobacter denitrificans and Stenotrophomonas maltophilia in association with diesel oil biodegradation enhanced with alkyl polyglucosides

The article concerns the influence of selected alkyl polyglucosides on biodegradation, cell surface and enzymatic properties of Stenotrophomonas maltophilia and Achromobacter denitrificans. The biodegradation of diesel oil depends on several factors including type and the amount of surfactant as well as bacterial genera used in the process. Nevertheless, a careful selection of these variables must be made as some bacterial strains prefer to use surfactants as their carbon source. This leads to the lowered biodegradation of diesel oil as can be observed for the tested S. maltophilia strain. Alkyl polyglucosides influenced the cell surface properties of both of the tested strains in slightly different ways. Especially for A. denitrificans, for which the hydrophobicity increased with concentration of both--Lutensol GD 70 and Glucopon 215 in diesel oil-surfactant systems. Moreover, judging by the efficiency of biodegradation, the most effective process was observed in the presence of Lutensol GD 70 (240 and 360 mg L(-1)) with biodegradation rising from 32% (without surfactant) to 68%. No such relation was observed for S. maltophilia.

Ionic liquids with a theophyllinate anion

Ammonium and piperidinium theophyllinate-based ILs were synthesized and characterized. Physicochemical properties, such as thermal stability, phase transition temperatures, viscosity, density, refractive index, as well as surface activity, feeding deterrence, antifungal activity and also biodegradability were determined. The synthesized theophyllinate-based ILs were surface active compounds. They exhibited insect-feeding deterrent activities. At the same time, the studied salts are also efficient fungicides and potential pesticidal ionic liquids. The obtained data suggest that certain structural modifications may increase their biodegradability in order to provide an environmentally friendly product.