Volume 66, Issue 10

Disposable screen-printed electrodes (SPCE) were modified using a cosmetic product to partially block the electrode surface in order to obtain a microelectrode array. The microarrays formed were electropolymerized with aniline. Scanning electron microscopy was used to evaluate the modified and polymerized electrode surface. Electrochemical characteristics of the constructed sensor for cadmium analysis were evaluated by cyclic and square-wave voltammetry. Optimized stripping procedure in which the preconcentration of cadmium was achieved by depositing at −1.20 V (vs. Ag/AgCl) resulted in a well defined anodic peak at approximately −0.7 V at pH 4.6. The achieved limit of detection was 4 × 10−9 mol dm−3. Spray modified and polymerized microarray electrodes were successfully applied to quantify cadmium in fish sample digests.

This paper deals with multielement profiling of microlements in the form of their isotopes 9Be, 51V, 59Co, 60Ni, 89Y, 111Cd, 208Pb, 232Th, and 238U. After their complexation by 4-(2-pyridylazo)resorcinol (PAR), 3,4-dihydroxy-9,10-dioxo-2-anthracenesulfonic acid sodium salt (ALS), 8-hydroxyquinoline-5-sulphonic acid (8-HQS), and ammonium pyrrolidinedithiocarbamate (APDC), the elements were preconcentrated and separated on Amberlite XAD-16 and Amberlite SDB-L prior to their analysis by inductively coupled plasma mass spectrometry. Various parameters such as pH, eluent type and volume, presence of surfactants and volume, and matrix effects on the retention of analytes were examined. Relative standard deviation and recovery values for four replicate determinations under optimal condition were in the range of 0.2–3.6 % and 59–98 %. The proposed method was applied to the determination of elements in lake water sample and industrial water. Recovery experiments with spiked water samples were performed.

The simple and rapid solid-phase micro-extraction method using gas chromatography was used for the identification and quantification of volatile aroma compounds in various types of processed cheese analogues produced from different types of fat (butter, butter oil, coconut oil, palm oil, and sunflower oil). In total, 31 organic compounds belonging to five chemical groups were identified, with the alcohols and fatty acids quantitatively predominant. The contents of the aroma compounds (the so-called aroma profiles) of the analogues and corresponding fats used as raw materials were compared. Significant differences (p < 0.05) were found between samples. The highest total content of aroma compounds was found in coconut oil analogue ((547.30 ± 9.82) mg kg−1), the lowest in palm oil analogue ((372.01 ± 16.16) mg kg−1). The concentrations of aroma compounds in fats were substantially lower (p < 0.05) than in analogues. Hence, the largest number of aroma analogues came from Edam cheese used for production as a protein source.

A speciation approach based on orthogonal chromatographic systems coupled to inductively coupled plasma mass spectrometry (ICP-MS) was used to characterise the biological response of free-living mice Mus spretus to environmental pollution caused by arsenic in different areas of the Doñana National Park (south-west Spain). The relative presence of inorganic and organic forms of arsenic was studied in cytosolic extracts from high metabolic activity organs of Mus spretus mice: kidneys, liver, and brain. An instrumental coupling of size-exclusion chromatography with UV and collision/reaction cell-ICP-MS detectors (SEC-UV-ICP-ORC-MS) both in analytical and preparative scale was used for this purpose. The results showed the presence of low molecular mass (LMM) molecules linked to arsenic in these tissues especially in the kidneys, where the presence of these arsenic metabolites was higher. On the other hand, the presence of these arsenicals varied from one area to the other, which can be related to a different occurrence of contaminants. These low molecular mass fractions were collected by preparative SEC chromatography for later study with ion exchange chromatography and detection by ICP-ORC-MS, using both anionic and cationic columns. The results showed the higher presence of MMA and DMA in kidneys of mice caught in contaminated areas and the existence of small amounts of unidentified arsenicals when cation-exchange chromatography was used, which could be related to the presence of dimethylarsinoylethanol (DMAE), thioarsenic species, or arsenocholine (AsC).

The total oil content and composition of fatty acids and phytosterols of five Transylvanian (Romania) pomaces of wild and cultivated blueberries (Vaccinium myrtillus), wild cowberry (Vaccinium vitis-idaea) and raspberry (Rubus idaeus), and cultivated black chokeberry (Aronia melanocarpa), were determined by capillary gas chromatography. Out of the five pomace oils, the percentages of polyunsaturated fatty acids (PUFAs) ranged from 37 % to 69 %. The lipid classes analysed (PLs — polar lipids, TGs — triacylglycerols, SEs — sterol esters) were separated and identified using thin-layer chromatography. TGs showed the highest PUFAs content (ranging from 41.9 % to 72.5 %) and PUFAs/SFAs (saturated fatty acids) ratios (in the range of 5.8–33.1 %). In the case of PL and SE fractions, the levels of SFA were significantly higher than in TGs. The total amount of sterols was in the range of 101.6–168.2 mg per 100 g of lipids of the pomaces analysed. The predominant phytosterols were β-sitosterol, stigmastanol + isofucosterol, and campesterol. The results indicated that the investigated pomace oils, due to their good balance between n-6 and n-3 fatty acids (except for chokeberry) and high β-sitosterol content, could be excellent sources of PUFAs and phytosterols, thus suggesting potential value-added utilisation of berry waste oils for preparing functional foods or food supplements.

The worldwide consumption of blueberries has increased due to their potential health effects. They contain micronutrients, various phytochemicals and anti-oxidant pigments, represented especially by anthocyanins. In addition to these, carotenoids and fatty acids are also present. The aim of this study was the identification and quantification of carotenoids (by HPLC) and fatty acids (by GC with flame ionisation detection) in two bilberry genotypes (Wild 1 and 2) and three cultivars (BlueCrop, Elliot, and Duke). The main carotenoids identified were lutein, β-cryptoxanthin, and β-carotene, with the average total carotenoid content of 266 μg per 100 g of fruit. The ratio of saturated fatty acids (SFAs) to polyunsaturated fatty acids (PUFAs) was 0.098 for Wild 1 and 0.11 for Wild 2 genotypes and ranged from 0.14 to 0.28 for cultivars. The main fatty acids identified were linoleic (18:2) and linolenic (18:3) acids in all the samples analysed. In Vaccinium myrtillus the amount of carotenoids and fatty acids was higher than in Vaccinium corymbosum species.

Apples are the most frequently consumed fruit and about 90 % of apple production is stored. Fatty acids and lipids are important constituents of plant cells. Disturbances in the lipid composition of fruit may lead to various stress processes, resulting in some storage disorders. This work is focused on an analysis of surface lipids of different varieties of apples stored in a normal atmosphere and a modified atmosphere with ultra-low oxygen content, for 4 months and 6 months. The major fatty acids in apple surface layers are palmitic acid, stearic acid, linoleic acid, and oleic acid. During the 6-months storage period, a variety-specific decrease in the total fatty acids content and an increase in saturation degree was observed in all the varieties tested, when compared with the 4-months storage. The greatest differences in saturation degree were observed in the Golden Delicious variety, in which the highest content of unsaturated fatty acids was also found. Microbial contamination of apple surfaces increased gradually over the storage process. Higher fungi levels were found in apples stored in the regular atmosphere than in the modified atmosphere, which can be attributed to changes observed in the total lipid content and saturation degree of the surface fatty acids and also to the sensitivity of microorganisms to the oxygen content in the storage room.

The aim of this work was to study the effect of various spices (cloves, cinnamon, allspice, white pepper, anise, star anise, coriander, fennel, nutmeg, cardamom, vanilla, and ginger) on acrylamide formation in buckwheat ginger cakes. The spices were characterised by their free radical scavenging activity and applied to formulation of the buckwheat ginger cakes in the same portions. After baking, the acrylamide content was determined by LC/ESI-MS-MS. The results showed a reduction in acrylamide content of up to 23 % in the buckwheat ginger cakes with the addition of nutmeg, fennel, anise, or cloves. A decrease in acrylamide content from 5 % to 11 % was found in the buckwheat ginger cakes with vanilla, cardamom, white pepper, or ginger. By contrast, the acrylamide content in the buckwheat ginger cakes with cinnamon or coriander increased by up to 29 %. No change in the acrylamide content was observed in the buckwheat ginger cakes with star anise or allspice. Only a slight correlation between the di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium (DPPH·) free radical scavenging activity of the added spices and the final acrylamide content in the buckwheat ginger cakes (0.68) was observed. The final acrylamide content was probably influenced not only by the free radical scavenging activity of the spices added, but also by their chemical composition and the reactiveness of particular constituents with synergistic/antagonistic effect in the matrix studied.

Hens’ eggs represent a rich source of important nutrients, including lipids and carotenoids. The lipid composition of hens’ eggs is influenced by genetic factors, age, and diet. The aim of this study was to compare the fatty acids, cholesterol, and carotenoids content of the egg yolk of ISA Brown and Araucana hens grown in free-range housing systems. Fatty acids and cholesterol were analysed by GC-FID and GC-MS and carotenoids were quantified by RP-HPLC-PDA. The Araucana egg yolk has a higher lipid content and higher egg-to-albumen ratio than the ISA Brown yolk, while the total cholesterol, carotenoids content and profile are not significantly different. The lipids of the Araucana egg yolk have a higher content of mono-unsaturated fatty acids (MUFAs), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) and a better n-6/n-3 ratio than the ISA Brown egg yolk lipids. The major carotenoids were lutein and zeaxanthin, which account for more than 83 % in egg yolk. Eggs of both breeds, when raised organically, represent very good sources of highly bio-available lutein and zeaxanthin, pigments which are related to lower risk of age-related macular degeneration. We report for the first time on the fatty acids composition in lipid fractions and the profile and content of carotenoids of the Araucana egg yolk.

The aim of this study was to modify or replace the PEVA foil (polyethylenevinylacetate) currently used in the Czech Army as a construction material for the NBC protective disposable suit JP-90 (a part of the OM-90 protective mask set). This material shows inadequate protective properties; therefore, barrier coatings based on melamine, Parylene (polyparaxylylene) and various types of SiOx were applied to its surface by vacuum technologies. The selected samples coated with polymer matrix barrier nanocoatings were continuously evaluated for resistance to permeation by highly toxic chemicals warfare agents (CWAs) and industrial pollutants at the Military Technical Institute of Protection (MTIP) in Brno. In addition, the microstructure of selected samples was assessed before and after the exposure to pollutants. The nanocoatings thus prepared were characterised in terms of surface morphology (SEM), chemical structure (FTIR), and oxygen transmission rate (OTR) at the Faculty of Chemistry, Brno University of Technology. Sulphur mustard (HD) was used to test the sample resistance to permeation. Cyclohexane and subsequently 1,6-dichlorhexane were used as substitute testing substances for HD; however, the latter proved to be more advantageous. The resulting OTR values are presented, along with the permeation by toxic substances, both for the initial uncoated and the barrier-layers-coated PEVA foil. The results show a difference in the mechanism of vapour permeation of CWAs and toxic volatile organic solvents (VOCs).

The aim of our work was to characterize linseed (Linum usitatissimum L.) genotypes divided into groups with high and low content of alpha-linolenic acid (ALA). Out of 32 linseed genotypes, 68.75 % represented high alpha-linolenic genotypes and 31.25 % were genotypes with low ALA content. Proportional representation of fatty acids was realized according to the norm (Czech Office for Standards, Metrology and Testing, 1994). Oil content was analyzed according to the internal methodology of Agritec Ltd., based on the norm (Czech Office for Standards, Metrology and Testing, 2011). The content of total fat ranged from 36.22 % to 46.35 %, that of ALA from 1.10 % to 65.20 %, and that of linoleic acid (LA) from 11.10 % to 75.00 % in the analyzed seed samples within all groups. The genotypes were divided also according to the seed color and a linear correlation between all three parameters within these groups was observed. Negative linear dependence was confirmed between parameters; ALA and LA content in the groups: high ALA brown seed (p < 0.0001; correlation coefficient (r) = −0.70), and high ALA yellow seed (p < 0.001; r = −0.36). Also, positive linear dependence between the total fat and the LA content in the groups: low ALA brown seed (p < 0.001; r = 0.34); low ALA yellow seed (p < 0.0001; r = 0.62), was found.

Functionalised triblock copolymers based on poly((lactic acid)-co-(glycolic acid)) and poly(ethylene glycol) (PLGA-PEG-PLGA) further modified with 3-methylenetetrahydrofuran-2,5-dione (itaconic anhydride; ITA) exhibited sol-gel transition induced by increasing temperature. Rheological properties of a series of ITA/PLGA-PEG-PLGA/ITA copolymer concentrations (6–24 mass %) in deionised Milli-Q water were studied by both the test tube inverting method (TTIM) and rheometer. The gel stiffness increased with the polymer concentration shifting the gel point of the copolymer to the lower temperature. The present study demonstrates that each method describes a sol-gel transition, but the combined method gives comprehensive information about changes in colour, viscosity, elastic and loss moduli. Characterisation of such a gel is necessary for its further use, in order to determine whether the material is appropriate as an injectable biomedical hydrogel.