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This work summarizes our research on synthesis, characterization and toxicity of selected UV-A filters and their antioxidant shield in commercial formulation - resveratrol. Benzophenone type of UV filters react under disinfection conditions with chlorine and form different mono- and dichlorinated products, while dibenzoylmethane derivatives, such as avobenzone, react with chlorine and form two main bridge chlorinated products followed by numerous chlorinated species at the advanced stages of the process. Resveratrol showed three main susceptible centers to chlorination, starting from the electrophilic addition to the double bond and continuing with the chlorination of the phenolic moieties. Several experiments conducted under different disinfection conditions (pool/sea water, addition of salts, irradiation) showed basically similar chlorination patterns with some variations in terms of product formation. The results of toxicity assessment using different test organisms (Vibrio fischeri, microalgae, daphnids) have shown different sensitivity of testing organisms to the parent UV filters in comparison with chlorinated products as well as different toxicity for specific UV filter in comparison to the others. As the closing loop of all experiments in the laboratory, an up-scaling to the real human skin is presented. [ABSTRACT FROM AUTHOR]

This document discusses the use of solid-phase microextraction (SPME) as a sample preparation technique for analyzing pollutants in various matrices, including food, plants, and the environment. SPME is a cost-effective and efficient method, often coupled with gas chromatography, for detecting volatile organic compounds (VOCs) in different substances. The document highlights the application of SPME in studying the aroma profiles of cheese, identifying microplastics, and analyzing flavors in tobacco products. The authors emphasize the need for standardized methods to compare different smoking products for regulatory purposes. [Extracted from the article]

"Raw food" diets are controversially accepted, but have been fashionable for a while and this trend seems to continue in the near future. Since the "raw food" diets are based on fruits, vegetables, nuts, seeds, sprouted grains and beans, higher daily intakes of this kind of food present a risk of higher intake of aflatoxins and oxalates, which consequently poses a health risk. The effect of the maximal temperature allowed at processing (46 ± 1 °C) has not yet been studied on aflatoxins and oxalates. In our study, their presence was determined by employing high pressure liquid chromatography with UV detection at the wavelength of 365 nm and 210 nm, respectively. A regression analysis was used to examine the changing of the content of oxalic acid and aflatoxin B1 over time. The content of "naturally" present aflatoxin B1 in selected dried fruits remained the same during 3 h of experiment at 46 ± 1 °C. On the contrary, the oxalate content in vegetables with low oxalic acid (tomatoes and chicory) decreased, whereas the temperature (46 ± 1 °C) had no effect on oxalic acid in spinach (higher oxalic content) and in pure solutions of oxalic acid in deionized water. [ABSTRACT FROM AUTHOR]

Volatile compounds (VCs) analysis was performed by solid-phase microextraction-gas chromatography-mass spectrometry. Main groups that define typical cheese flavour formed as a result of the addition of a starter culture (SC). The cheesemaking environment, the type of milk (cow, ewe, goat), and the heat treatment of milk were observed. The SC had influenced the total amount of some fatty acids and ketones. Compared to cow and ewe cheeses, goat cheese had higher values of hexanoic and octanoic acids, however, two alcohols, 1-hexanol, 2-ethyl- and hexanol, were only present in cow cheeses. We confirmed that the cheesemaking environment is also an important parameter influencing VC profiles of cheese. Higher amount of esters and the absence of 2-phenylethanol were observed in raw milk cheese, compared to thermised milk cheese where δ-octalactone was present. [ABSTRACT FROM AUTHOR]

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Nanos cheese is a hard type of cheese produced from milk obtained from cows grazing in a limited specific geographic area (Vipava valley, Slovenia). This study is the first report about the influence of certain technological parameters and their impact on the Nanos cheese flavour, which can be meant as a model of hard-type cheeses. Apart from collecting the milk from different geographic areas, ripening location, ripening method (classical vs in grape marc), ripening temperature (12 °C, 18 °C) and the amount of starter culture were changed and evaluated. For the determination of the profile of volatile organic compounds (VOCs) in the cheese, solid phase micro extraction (SPME) coupled to gas chromatography - mass spectrometry (GC-MS) was used. Doubling the addition of the starter culture contributed to higher levels of certain VOCs (e.g. benzaldehyde responsible for nutty flavour). Higher temperature during ripening increased the content of some ethyl esters and alcohols from 2 to 10-fold and it had an effect on appearance of the cheese. It was also observed that cheeses ripened in grape marc had a higher content of most esters. The differences in VOCs profile were not significant in cheeses from different geographic areas and ripening locations. [ABSTRACT FROM AUTHOR]

Abstract: This research focused on photocatalytic degradation of imidacloprid, thiamethoxam and clothianidin employing a tailor-made photoreactor with six polychromatic fluorescent UVA (broad maximum at 355nm) lamps and immobilised titanium dioxide (TiO2) on glass slides. The disappearance was followed by high pressure liquid chromatography (HPLC–DAD) analyses, wherein the efficiency of mineralization was monitored by measurements of total organic carbon (TOC). Within 2h of photocatalysis, all three neonicotinoids were degraded following first order kinetics with rate constants k =0.035±0.001min−1 for imidacloprid, k =0.019±0.001min−1 for thiamethoxam and k =0.021±0.000min−1 for clothianidin. However, the rate of mineralization was low, i.e. 19.1±0.2% for imidacloprid, 14.4±2.9% for thiamethoxam and 14.1±0.4% for clothianidin. This indicates that several transformation products were formed instead. Some of them were observed within HPLC–DAD analyses and structures were proposed according to the liquid chromatography–electro spray ionization tandem mass spectrometry analyses (LC–ESI–MS/MS). The formation of clothianidin, as thiamethoxam transformation product, was reported for the first time. [Copyright &y& Elsevier]

Inhibition of bovine erythrocyte acetylcholinesterase (free and immobilized on controlled pore glass) by separate and simultaneous exposure to malathion and malathion transformation products which are generally formed during storage or through natural or photochemical degradation was investigated. Increasing concentrations of malathion, its oxidation product malaoxon, and its isomerisation product isomalathion inhibited free and immobilized AChE in a concentration-dependent manner. KI, the dissociation constant for the initial reversible enzyme inhibitor-complex, and k3, the first order rate constant for the conversion of the reversible complex into the irreversibly inhibited enzyme, were determined from the progressive development of inhibition produced by reaction of native AChE with malathion, malaoxon and isomalathion. KI values of 1.3 x 10(-4) M(-1), 5.6 x 10(-6) M(-1) and 7.2 x 10(-6)M(-1) were obtained for malathion, malaoxon and isomalathion, respectively. The IC50 values for free/immobilized AChE, (3.7 +/- 0.2) x 10(-4) M/(1.6 +/-0.1) x 10(-4), (2.4 +/- 0.3) x 10(-6)/(3.4 +/- 0.1) x 10(-6)M and (3.2 +/- 0.3) x 10(-6) M/(2.7 +/- 0.2) x 10(-6) M, were obtained from the inhibition curves induced by malathion, malaoxon and isomalathion, respectively. However, the products formed due to photoinduced degradation, phosphorodithioic O,O,S-trimethyl ester and O,O-dimethyl thiophosphate, did not noticeably affect enzymatic activity, while diethyl maleate inhibited AChE activity at concentrations > 10mM. Inhibition of acetylcholinesterase increased with the time of exposure to malathion and its inhibiting by-products within the interval from 0 to 5 minutes. Through simultaneous exposure of the enzyme to malaoxon and isomalathion, an additive effect was achieved for lower concentrations of the inhibitors (in the presence of malaoxon/isomalathion at concentrations 2 x 10(-7) M/2 x 10(-7) M, 2 x 10(-7) M/3 x 10(-7)M and 2 x 10(-7) M/4.5 x 109-7) M), while an antagonistic effect was obtained for all higher concentrations of inhibitors. The presence of a non-inhibitory degradation product (phosphorodithioic O,O,S-trimethyl ester) did not affect the inhibition efficiencies of the malathion by-products, malaoxon and isomalathion.