Tomasz Grześkowiak

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.

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.

Investigations on the biodegradation of alkylpolyglucosides by means of liquid chromatography–electrospray mass spectrometry

The biodegradation of alkylpolyglucosides (APGs) was studied under the conditions of the OECD Screening Test with activated sludge as an inoculum. An influence of alkyl and sugar chain length on the biodegradation rate and a central scission pathway of the biodegradation were investigated. The liquid chromatography–electrospray mass spectrometry technique was used for alkylpolyglucoside analysis and for identification and semiquantitative determination of metabolites. It was found that APGs with a longer alkyl chain were biodegraded faster than those with a shorter one. However, a longer sugar chain caused slower biodegradation of APGs. The central scission pathway of biodegradation was also confirmed.

Application of dispersive liquid-liquid microextraction followed by HPLC-MS/MS for the trace determination of clotrimazole in environmental water samples.

A method for the analysis of clotrimazole was developed with dispersive liquid-liquid microextraction for sample pre-concentration and HPLC-MS/MS for analysis. A linear ion trap was used for the confirmation of clotrimazole identity in the samples. The developed method enables the analysis of clotrimazole in river water and sewage effluent from wastewater treatment plants with a LOQ of 0.7 ng/L. Environmental monitoring of clotrimazole was undertaken. Samples from river water and sewage effluents were analysed over a one-year period. Clotrimazole was found in every tested sample with concentration range from 1 to 31 ng/L. The amount of clotrimazole in tested samples was highly dependent on sampling season. The highest results were obtained in summer and autumn.

Determination of alkylphenols and their short-chained ethoxylates in Polish river waters

A simple and robust analytical method for analysis of octyl- and nonylphenol as well as their short-chained ethoxylates in river water was proposed. Quantification of these analytes was performed by high-performance liquid chromatography with fluorescence detection after isolation using solid phase extraction with polytetrafluoroethylene sorbent. The method allowed one to obtain about 80–100% recovery for octylphenol and its ethoxylates and 70–80% for nonylphenol and its ethoxylates. Also, there was no need for additional sample cleaning before chromatographic analysis. The limit of detection was 0.01 µg L−1 for octylphenol and its ethoxylates and 0.03 µg L−1 for nonylphenol and its ethoxylates. The proposed method was used for quantitation of octyl- and nonylphenol together with their short-chained ethoxylates. Nonylphenol, nonylphenol mono- and diethoxylates were detected at concentrations ranging from 0.12 to 0.53 µg L−1. Octylphenol, octylphenol mono- and diethoxylates were detected in four out of eleven samples at concentrations ranging from 0.03 to 0.17 µg L−1. High concentrations of nonylphenol and its ethoxylates were found in the samples, despite the fact that their use in European countries was forbidden several years ago.

Determination of Glutamic Acid and Aspartic Acid in Tomato Juice by Capillary Isotachophoresis

A capillary isotachophoresis method was developed and applied for determination of glutamic acid and aspartic acid in tomato juice samples. The leading electrolyte was 10 mmol L−1 L-histidine monohydrochloride including 1% poly (vinylpyrrolidone) adjusted with histidine to pH 5.5. The terminating electrolyte was 5 mmol L−1 2-morpholineethanesulfonic acid adjusted to pH 6.0 with tris(hydroxymethyl)aminomethane. It was proved that the developed method is suitable for a routine analysis of glutamic and aspartic acid in tomato juice. The simplicity and low cost of this analytical procedure makes the technique a good alternative to high performance liquid chromatography. Usefulness of the method was tested on different varieties of tomatoes as well as different ripeness stages of the fruits. Moreover, commercial tomato juices were also analysed.

Determination of Parabens in Polish River and Lake Water as a Function of Season

ABSTRACT A method for the determination of methylparaben, ethylparaben, propylparaben, butylparaben, and benzylparaben is reported. A polymeric cartridge containing ultra-pure polystyrene cross-linked with 50% divinylbenzene and 50% poly(methyl methacrylate) was employed for the isolation of parabens from water samples. The extracted samples were analyzed by high-performance liquid chromatography coupled with tandem mass spectrometry. The limits of detection for the method were from 0.3 to 2.9 ng L−1 that allowed the determination of parabens in river and lake water samples with suitable precision and accuracy. There was high variability in the results depending on time of sample collection. The highest concentrations were obtained for samples collected in July – up to 466 ng L−1 of methylparaben and 144 ng L−1 of propylparaben.

The use of a triple quadrupole linear ion trap mass spectrometer with electrospray ionisation for fragmentation studies of selected antifungal drugs

Fragmentation studies of three antifungal drugs, clotrimazole, fluconazole and clioquinol ,were performed. A triple quadrupole linear ion trap mass spectrometer was used for this purpose. This type of equipment enables MS(3) spectra to be obtained which lead to better understanding of fragmentation pathways. Nevertheless, it is rarely used for fragmentation studies. The results obtained here for the antifungal drugs gave further insight into fragmentation pathways of clotrimazole and fluconazole. Moreover, fragmentation of clioquinol was investigated which had not been presented before.

Surface properties of titanate-modified silica gel as measured by inverse gas chromatography

Silica gel was modified at three temperatures by five titanium coupling agents: tris(isooctadecanoato-O)(2-propanolato)titanium, [2-[2-(methoxy-O)ethoxy-O]ethanolato-O]tris(2-methyl-2-propenoato-O)titanium, (isooctadecanoato-O)bis(2-methyl-2-propenoato-O)(2-propanolato)titanium, (4-aminobenzenesulfonato-O)bis(dodecylbenzenesulfonato-O)(2-propanolato)titanium and tris(dodecylbenzenesulfonato-O)(2-propanolato)titanium. Surface properties of these modified materials were measured by inverse gas chromatography and expressed by surface parameters (γds, KA, KD). The influence of the modifier structure and modification temperature on surface parameters is presented and discussed. Relationships between surface parameters and solubility parameters used earlier for the description of the physico-chemical state of the modifier monolayer are also shown.