Ludmila Mravcová

Application of comprehensive two-dimensional gas chromatography with mass spectrometric detection for the analysis of selected drug residues in wastewater and surface water

Pharmaceutical residues have become tightly controlled environmental contaminants in recent years, due to their increasing concentration in environmental components. This is mainly caused by their high level of production and everyday consumption. Therefore there is a need to apply new and sufficiently sensitive analytical methods, which can detect the presence of these contaminants even in very low concentrations. This study is focused on the application of a reliable analytical method for the analysis of 10 selected drug residues, mainly from the group of non-steroidal anti-inflammatory drugs (salicylic acid, acetylsalicylic acid, clofibric acid, ibuprofen, acetaminophen, caffeine, naproxen, mefenamic acid, ketoprofen, and dicofenac), in wastewaters and surface waters. This analytical method is based on solid phase extraction, derivatization by N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) and finally analysis by comprehensive two-dimensional gas chromatography with Time-of-Flight mass spectrometric detection (GCxGC-TOF MS). Detection limits ranged from 0.18 to 5 ng/L depending on the compound and selected matrix. The method was successfully applied for detection of the presence of selected pharmaceuticals in the Svratka River and in wastewater from the wastewater treatment plant in Brno-Modrice, Czech Republic. The concentration of pharmaceuticals varied from one to several hundreds of ng/L in surface water and from one to several tens of isg/L in wastewater.

Effect of ethanol and hydrogen peroxide on poly(3-hydroxybutyrate) biosynthetic pathway in Cupriavidus necator H16

Exposition of Cupriavidus necator to ethanol or hydrogen peroxide at the beginning of the stationary phase increases poly(3-hydroxybutyrate) (PHB) yields about 30%. Hydrogen peroxide enhances activity of pentose phosphate pathway that probably consequently increases intracellular ratio NADPH/NADP+. This effect leads to stimulation of the flux of acetyl-CoA into PHB biosynthetic pathway and to an increase of enzymatic activities of β-ketothiolase and acetoacetyl-CoA reductase while activity of PHB synthase remains uninfluenced. During ethanol metabolisation, in which alcohol dehydrogenase is involved, acetyl-CoA and reduced coenzymes NAD(P)H are formed. These metabolites could again slightly inhibit TCA cycle while flux of acetyl-CoA into PHB biosynthetic pathway is likely to be supported. As a consequence of TCA cycle inhibition also less free CoA is formed. Similarly with hydrogen peroxide, activities of β-ketothiolase and acetoacetyl-CoA reductase are increased which results in over-production of PHB. Molecular weight of PHB produced under stress conditions was significantly higher as compared to control cultivation. Particular molecular weight values were dependent on stress factor concentrations. This could indicate some interconnection among activities of β-ketothiolase, acetoacetyl-CoA reductase and PHB molecular weight control in vivo.

Comparison of extraction techniques for the isolation of explosives and their degradation products from soil

A comparison of four extraction techniques used for the isolation of 14 explosive compounds (Method 8330-Explosives) from spiked soil samples is described. Soxhlet warm extraction (SWE), pressurized solvent extraction (PSE), microwave assisted extraction (MAE) and supercritical fluid extraction (SFE) were included. The effects of basic extraction conditions – i.e. type of extraction solvent, temperature, pressure, and extraction time – were investigated. The best extraction recovery of the monitored compounds from spiked soil was obtained using pressurized solvent extraction. Recoveries of explosives using the PSE technique were in the range from 65 to 112%. Extraction recoveries by Soxhlet warm extraction and supercritical fluid extraction reached 65–99% and 52–75%, respectively. The lowest extraction recoveries (28–65%) were obtained using microwave assisted extraction. A very low extraction recovery for tetryl was observed in all cases but the best results were achieved by pressurized solvent extraction (58%).

The Effect of Processing of Polycaprolactone Films on Degradation Process Initiated by Aspergillus Oryzae Lipase

Poly(ϵ-caprolactone) (PCL) films with Mn = 18 kDa obtained by compression molding (CM) or solution casting (SC) were subjected to Aspergillus oryzae (AO) lipase action in a phosphate buffer at pH 7 at 37°C. The appearance of randomly oriented cracks on the surface of incubated PCL films accompanied by a decrease of the weight-average molecular weight (Mw) by 10% was observed after 42 days. The increase of crystallinity and surface morphology pattern of PCL samples exposed to AO lipase action supported the fact that the degradation proceeded in the amorphous phase of the aged films. SC films were degraded faster, probably due to better accessibility of ester bonds in the amorphous phase of spherulites.

The Use of Methods of Environmental Analysis and Ecotoxicological Tests in the Evaluation of Wastewater

The term “new” environmental pollutant covers all anthropogenic contaminants that have been released in the environment over the last few decades. Research into their fate and impact on the environment has started relatively recently. The group of new environmental pollutants consists of persistent organic pollutants (POPs) including DDT, polychlorinated biphenyls, polycyclic aromatic hydrocarbons and a wide range of organic pesticides. This group has recently been expanded with polybrominated flame retardants, drugs, detergents, and personal hygiene products. Chemicals, used everyday in homes, industry and agriculture, can enter the environment in wastewater. According to the United Nations Organization 884 million people do not have access to safe drinking water, and over 2.6 billion people do not have access to proper sanitation systems. On July 28, 2010, the UN General Assembly passed a resolution supporting water as a human right and urging governments and international organizations to address this important human right. Interest in the presence of pharmaceuticals, personal care products, and endocrine disruptors in the environment has increased significantly over the last decade. Pharmaceuticals and synthetic musk compounds in personal care products (PPCPs), are groups of organic micropollutants which are routinely detected in surface water, ground water and even in drinking water (McClellan and Halde, 2010). Hundreds of tons of these compounds are dispensed in communities every year. PPCPs are regarded as being potentially hazardous compounds as some are ubiquitous, persistent and biologically active compounds with recognised endocrine disruption functions (Kasprzyk-Hordern et. al., 2002). Many pharmaceuticals, upon administration, are degraded in the body and may even become inactive, but others, often those applied externally, excreted or not absorbed fully, can leave the body in their active forms. (Roberts &Thomas, 2006). The others only slightly transformed or even unchanged often conjugated to endogenous substrate (e.g. glucuronic acid, sulfuric acid, acetic acid to polar molecules. (Roberts and Thomas, 2006). These conjugates are easily cleaved during sewage treatment and, thus, several pharmaceutically active compounds (PhACs) are discharged almost unchanged from municipal sewage treatment plants (STPs) into the receiving waters (Heberer, 2002). The wide range of trace chemical contaminants persisting in municipal wastewater after conventional treatment