Urszula Kotowska

HS-SPME/GC–MS analysis of volatile and semi-volatile organic compounds emitted from municipal sewage sludge

The aim of the research involved identification and semi-quantitative determination of unknown volatile and semi-volatile organic compounds emitted to air by sewage sludge formed in the process of municipal wastewater treatment in a sewage treatment plant. Samples taken directly after completion of the technological process as well as the sludge stored on the premise of the sewage treatment plant were analyzed. A simple method using off-line headspace solid-phase microextraction combined with gas chromatography–mass spectrometry has been proposed for extraction and detection of organic pollutants. For reliable identification of compounds, combination of two independent parameters: mass spectra and linear temperature programmed retention indices were employed. Over 170 compounds of different structure were identified including aliphatic and aromatic hydrocarbons, alcohols, esters, carbonyls, as well as sulfur, nitrogen, and chlorine containing compounds. The prevailing substances included: ethyl ether, n-hexane, p-xylene, o-xylene, mesitylene, m-ethylbenzene, limonene, n-decane, n-undecane, and n-dodecane. A few compounds such as methanetiol, dimethyl polisulfide, octaatomic sulfur, phthalic anhydride, and indoles were identified in the sludge for the first time.

Studies on photodegradation of levomepromazine and olanzapine under simulated environmental conditions

The present study discusses the influence of sunlight on the photostability of levomepromazine (LV) and olanzapine (OLA) hydrochlorides in river water. Four samples of water from different rivers were used in the research. In their course, it turned out that levomepromazine easily underwent photooxidation under simulated environmental conditions, resulting in the generation of its sulphoxide. Olanzapine, on the other hand, appeared to be more resistant to sunlight, as its photodecomposition proceeded slowly, and only one product of its decomposition was detected spectrophotometrically during the process. The photodegradation was analyzed in detail using principal component analysis (PCA) and multivariate curve resolution alternating least squares (MCR-ALS) chemometric methods, and the outcomes verified by HPLC and GC-MS analysis. It can be stated that the rates of the observed processes heavily depended on the chemical composition of the fresh water used in the experiments.

Partition coefficients of ketones, phenols, aliphatic and aromatic acids, and esters in n-hexane/nitromethane

AbstractLiquid-liquid partition is used in sample preparation and in countercurrent and liquid-liquid chromatographic separations. Partition coefficients are widely used in toxicology, environmental, and analytical chemistry. The Khn determination procedure for the n-hexane/nitromethane system was optimized and partition coefficients for 99 ketones, esters and trimethylsilyl derivatives of phenols, aliphatic and aromatic acids were determined. For 130 compounds, Khn values were predicted using mathematical relationships between Khn and other physicochemical and structural parameters.

Gas chromatographic-mass spectrometric investigation of the chemical composition of the aquatic plant Wolffia arrhiza (Lemnaceae)

The ether and methanol extracts of Wolffia arrhiza (Lemnaceae) were analyzed using high resolution capillary gas chromatography coupled with mass spectrometry (GC-MS). The ether extract contains 32 compounds, mostly lipids and sterols, among which β-sitosterol is most prevalent. This is the first evidence of β-sitosterol detection in W. arrhiza. The most representative group of polar compounds of the methanol fraction is formed by 18 free amino acids. In addition, in the methanol extract there are a number of other nitrogen containing compounds: nucleobase and nucleosides. The third significant group in the total ion current in the methanol extract is formed by glycerol and glycerides. At the same time, the content of free sugar is very low.

Use of direct immersion solid-phase microextraction on polyacrylate and polydimethylsiloxane stationary phases for simultaneous determination of the neutral and basic pharmaceuticals in wastewater

AbstractDirect immersion solid-phase microextraction has been optimized and applied to the simultaneous determination of the neutral and basic pharmaceuticals: caffeine, carbamazepine, clomipramine, chlorprothixene and clotrimazole at low concentrations in municipal wastewater. Two absorption type stationary phases: polydimethylsiloxane (PDMS) and polyacrylate (PA) have been found to be most effective for extraction of target analytes. The separation and detection were carried out by gas chromatograph coupled with mass spectrometer working in the selected ion monitoring mode. The method was validated for linearity, detection and quantitation limits, selectivity and precision. The average correlation coefficient of the calibration curves was 0.9933. The LOD values in influent and effluent wastewater were in the range of 10–145 ng L−1 and 4–111 ng L−1, respectively, which were a bit higher than those in the deionized water due to matrix effect. The high values of distribution coefficient (Kfs) in PDMS/water and PA/water systems (log Kfs between 3.05 and 4.23) indicates the very high applicability of these stationary phases for determination of carbamazepine, clomipramine, chlorprothixene and clotrimazole in water samples.