UV-Induced fingerprint spectroscopy

Here, we present the potential analytical applications of photochemistry in combination with fluorescence fingerprinting. Our approach analyzes the fluorescence of samples after ultraviolet light (UV) treatment. Especially in presence of metal ions and thiol-containing compounds, the fluorescence behavior changes considerably. The UV-induced reactions (changes) are unique to a given sample composition, resulting in distinct patterns or fingerprints (typically in the 230-600 nm spectral region). This method works without the need for additional chemicals or fluorescent probes, only suitable diluent must be used. The proposed method (UV fingerprinting) suggests the option of recognizing various types of pharmaceuticals, beverages (juices and wines), and other samples within only a few minutes. In some studied samples (e.g. pharmaceuticals), significant changes in fluorescence characteristics (mainly fluorescence intensity) were observed. We believe that the fingerprinting technique can provide an innovative solution for analytical detection.

UV-Induced Nanoparticles-Formation, Properties and Their Potential Role in Origin of Life

Inorganic nanoparticles might have played a vital role in the transition from inorganic chemistry to self-sustaining living systems. Such transition may have been triggered or controlled by processes requiring not only versatile catalysts but also suitable reaction surfaces. Here, experimental results showing that multicolor quantum dots might have been able to participate as catalysts in several specific and nonspecific reactions, relevant to the prebiotic chemistry are demonstrated. A very fast and easy UV-induced formation of ZnCd quantum dots (QDs) with a quantum yield of up to 47% was shown to occur 5 min after UV exposure of the solution containing Zn(II) and Cd(II) in the presence of a thiol capping agent. In addition to QDs formation, xanthine activity was observed in the solution. The role of solar radiation to induce ZnCd QDs formation was replicated during a stratospheric balloon flight.

Analysis of defensive secretion of a milkweed bug Lygaeus equestris by 1D GC-MS and GC×GC-MS: sex differences and host-plant effect

The composition of defensive secretion produced by metathoracic scent glands was analysed in males and females of the milkweed bug Lygaeus equestris (Heteroptera) using gas chromatography with mass spectrometric detection (GC-MS). The bugs were raised either on cardenolide-containing Adonis vernalis or on control sunflower seeds in order to determine whether the possibility to sequester cardenolides from their host plants would affect the composition of defensive scent-gland secretion. Profiles of the composition of defensive secretions of males and females raised on sunflower were closely similar, with predominant presence of (E)-2-octenal, (E)-2-octen-1-ol, decanal and 3-octen-1-ol acetate. The secretion of bugs raised on A. vernalis was more sexually dimorphic, and some chemicals e.g. (E,E)-2,4-hexadienyl acetate and 2-phenylethyl acetate were dominant in males, but absent in females. Compared to bugs from sunflower, the scent-gland secretion of bugs raised on A. vernalis was characterized by lower overall intensity of the peaks obtained for detected chemicals and by absence of some chemicals that have supposedly antipredatory function ((E)-2-hexenal, (E)-4-oxo-hex-2-enal, 2,4-octadienal). The results suggest that there might be a trade-off between the sequestration of defensive chemicals from host plants and their synthesis in metathoracic scent-glands.

Comparative Analysis of Volatile Defensive Secretions of Three Species of Pyrrhocoridae (Insecta: Heteroptera) by Gas Chromatography-Mass Spectrometric Method

The true bugs (Hemiptera: Heteroptera) have evolved a system of well-developed scent glands that produce diverse and frequently strongly odorous compounds that act mainly as chemical protection against predators. A new method of non-lethal sampling with subsequent separation using gas chromatography with mass spectrometric detection was proposed for analysis of these volatile defensive secretions. Separation was performed on Rtx-200 column containing fluorinated polysiloxane stationary phase. Various mechanical irritation methods (ultrasonics, shaking, pressing bugs with plunger of syringe) were tested for secretion sampling with a special focus on non-lethal irritation. The preconcentration step was performed by sorption on solid phase microextraction (SPME) fibers with different polarity. For optimization of sampling procedure, Pyrrhocoris apterus was selected. The entire multi-parameter optimization procedure of secretion sampling was performed using response surface methodology. The irritation of bugs by pressing them with a plunger of syringe was shown to be the most suitable. The developed method was applied to analysis of secretions produced by adult males and females of Pyrrhocoris apterus, Pyrrhocoris tibialis and Scantius aegyptius (all Heteroptera: Pyrrhocoridae). The chemical composition of secretion, particularly that of alcohols, aldehydes and esters, is species-specific in all three pyrrhocorid species studied. The sexual dimorphism in occurrence of particular compounds is largely limited to alcohols and suggests their epigamic intraspecific function. The phenetic overall similarities in composition of secretion do not reflect either relationship of species or similarities in antipredatory color pattern. The similarities of secretions may be linked with antipredatory strategies. The proposed method requires only a few individuals which remain alive after the procedure. Thus secretions of a number of species including even the rare ones can be analyzed and broadly conceived comparative studies can be carried out.

Supramolecular structures based on regioisomers of cinnamyl-α-cyclodextrins - new media for capillary separation techniques

This work focuses on the preparation and application of supramolecular structures based on mono-cinnamyl-α-cyclodextrins (Cin-α-CD). Pure regioisomers of Cin-α-CD having the cinnamyl moiety at the 2-O- or at the 3-O-position, respectively, were prepared, characterized and applied in capillary electrophoresis as additives to the background electrolyte. These new monomer units with a potential to self-organize into supramolecular structures were synthesized via a straightforward one-step synthetic procedure and purified using preparative reversed-phase chromatography allowing a large scale separation of the regioisomers. The ability of the monomers to self-assemble was proved by various methods including NMR spectroscopy and dynamic light scattering (DLS). The light scattering experiments showed that the monomer units have distinguishable ability to form supramolecular structures in different solvents and the size distribution of the aggregates in water can be easily modulated using different external stimuli, such as temperature or competitive guest molecules. The obtained results indicated that the two regioisomers of Cin-α-CD formed different supramolecular assemblies highlighting the fact that the position of the cinnamyl group plays an important role in the intermolecular complex formation.

Use of 6-O-mono-substituted derivatives of β-cyclodextrin-bearing substituent with two permanent positive charges in capillary electrophoresis

This study details the use of two permanently positively charged mono-substituted

Reducing environmental impact of dairy cattle: a Czech case study

We analyze options to reduce the future environmental impact of dairy cattle production, using an optimization model (DAIRY) applied to the Czech Republic. The DAIRY model can be used to calculate the overall environmental impact (OEI). We show that aquatic eutrophication and global warming are the 2 most important problems caused by dairy cattle. These problems are largely caused by nitrate leaching and emissions from animal housing. The DAIRY model indicates that the costs of reducing the OEI in 2020 by 20% are 12 MEuro. It is most cost effective to achieve this reduction by improving the efficiency of animal manure used as fertilizer. We tested the sensitivity of the model to assumptions about the following: 1) the relative importance of environmental problems as expressed in weighting factors, and 2) future cattle numbers and milk yield per milking cow. The first case indicates that disagreement on which problem is most urgent need not lead to disagreement about policies to be undertaken. Regardless of the weighting factors used, aquatic eutrophication and global warming are the most important problems. However, the overall costs of reducing the OEI differ with alternative sets of weighting factors, because the costs of emission reduction differ among pollutants. The second case shows that the DAIRY model results are more sensitive to changes in cattle numbers than to changes in milk yield. This study is the first integrated assessment of dairy cattle production for a Central European country and illustrates how systematic analyses may help to find optimal solutions.

Environmental and health impact by dairy cattle livestock and manure management in the Czech Republic

In this study we evaluate the potential environmental and health impact of dairy cattle livestock and manure management in the Czech Republic. We present a new approach for national assessments of the environmental impact of an agricultural sector. Emission estimates are combined with a country-specific set of indicators to assess the environmental impact in nine regions with specific environmental characteristics. We estimate the contribution of emissions of ammonia (NH3) and nitrogen oxides (NO) to acidification and terrestrial eutrophication, nitrate (NO3) and phosphate (PO4) to aquatic eutrophication, nitrogen oxides (NO), particulate matter (PM10) and (PM2.5) to human toxicity and methane (CH4) and nitrous oxide (NO) to global warming. We present large regional differences in the environmental and health impact per unit of agricultural production. The regional acidifying, eutrophying and global warming impact of dairy cattle is calculated to be up to three times the national average, depending on the dairy cattle intensity. Aquatic eutrophication is found to be a problem in regions with relatively high eutrophying emissions per hectare of so-called nitrate vulnerable zones. Human toxicity problems caused by dairy cattle livestock and manure management are problematic in regions with a high population density in rural areas. The strength of our approach is the use of country-specific characterisation factors to assess the potential environmental and health impact of agriculture at the sub-national scale. We were able to analyse the potential environmental impact without explicit quantification of specific effects on humans and ecosystems. The results can be used to identify the most polluted areas as well as appropriate targets for emission reduction.

Evaluation of methods for quantifying agricultural emissions of air, water and soil pollutants

Integrated assessments that analyze global warming, acidification, eutrophication and ozone related problems simultaneously, need complete, detailed and consistent emission estimates that consider possible interrelations between different pollutants. We discuss three types of emission estimation methods: emission factor, regression analyses and process-based methods. Selected examples of these are reviewed to illustrate the large variety in methods available. We present an approach for the evaluation of emission estimation methods which follows three steps: (1) Comparison, (2) Scoring and (3) Multi-Criteria Analysis (MCA). We demonstrate the usefulness of this approach by applying it to a case study for the Czech Republic. Firstly we compare selected methods with respect to characteristics which we consider as requirements to quantify emissions of air, water and soil pollutants in an integrated way. We observe that none of the selected methods fully meet our defined characteristics. Secondly, we score the methods with respect to three types of criteria. This evaluation reveals large differences between the methods. We conclude that the following methods best meet our criteria: the IPCC Guidelines, methods from INITIATOR, and the detailed method of the EMEP/CORINAIR Guidebook. Finally, we perform a Multi-Criteria Analysis to analyze how our conclusions change if one considers certain criteria as more important than others. Based on this analysis we suggest that combining parts of each of the three methods forms a sound basis for a new emission estimation method for quantifying agricultural emissions of air, water and soil pollution simultaneously.