Performed experiments and simulations of petroleum microbiological degradation may serve for the prediction of the fate of petroleum type pollutants, as well as for definition of conditions for bioremediation of some environmental segments.

The goal of this work was to investigate the relationship between antioxidants' content and the oxidative stabilities of grape seed oils obtained from the Cabernet Sauvignon variety. The samples of grape seed oils were obtained by ultrasound assisted extraction. The time of extraction was varied, while the other relevant parameters: extraction temperature, solvent to solid ratio and sonication power were kept constant. For the sake of comparison, the extraction was also done using the conventional Soxhlet method. For all the oil samples obtained, the contents of total phenolic compounds (TPC), atocopherol and fatty acids were determined using relevant analytic methods. Importantly, in the present study, the modern analytical techniques for estimation of antioxidant capacity (measuring the chemiluminescence intensity of a luminol-hemin solution) and oxidative stability [differential scanning calorimetry (DSC), coupled with thermogravimetry (TG)] were proposed. The obtained results prove that ultrasonic irradiation enables effective extraction of grape seed oil. It was shown that the extractive yields and the amounts of total phenolic compounds and atocopherol increase with time of extraction; the optimum time was determined. Results obtained in this work show that, for both oxidative stability and antioxidant capacity, TPC have a more important role then a-tocopherol.

No abstract

Antioxidant (AO) capacity of various medicinal plants extracts and phenolic compounds was assessed by the most widely used spectrophotometric assays such as ferric reducing antioxidant power (FRAP) and scavenging of 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH). In addition, two direct current (DC) polarographic assays, one based on a decrease of anodic current of [Hg(O2H)(OH)] - HydroxoPerhydroxoMercury(II) Complex (HPMC) formation in alkaline solution of H2O2, at the potential of mercury dissolution and another recently developed Mercury Reduction Antioxidant Power (MRAP), based on a a decrease of cathodic current of Hg(II) reduction were employed. Percentage of both currents decrease was plotted versus the volume of gradually added complex samples or the amount of individual ones and the slopes of these plots were used to express AO capacity. Total phenolic content (TPC) of extracts was determined by Folin- Ciocalteu (FC) assay. Correlations between applied assays were calculated by regression analysis. Relative Antioxidant Capacity Index (RACI), calculated by assigning equal weight to all applied assays and Phenolic Antioxidant Coefficients (PAC), calculated as a ratio between particular AO capacity and TPC, were used to achieve more comprehensive comparison between analyzed samples, as well as applied assays.

The kinetics of the formation of poly(carbosiloxane), as well as of alkylsubstituted poly(siloxane), by Karstedt's catalyst catalyzed hydrosilylation were investigated. Linear poly(carbosiloxane), poly[(1,1,3,3-tetramethyldisiloxanyl)ethylene], (PTMDSE), was obtained by hydrosilylation of 1,3-divinyltetramethyldisiloxane (DVTMDS) and 1,1,3,3-tetramethyldisiloxane (TMDS), while alkyl-substituted poly(siloxane), poly(methyldecylsiloxane), (PMDS), was synthesized by hydrosilylation of poly(methylhydrosiloxane) (PMHS) and 1-decene. To investigate the kinetics of PTMDSE formation, two series of experiments were performed at reaction temperatures ranging from 25 to 56 8C and with catalyst concentrations ranging from 7.0 3 10 À6 to 3.1 3 10 À5 mol Pt/mol CH¼ ¼CH 2 . A series of experiments was performed at reaction temperatures ranging from 28 to 48 8C, with catalyst concentrations of 7.0 3 10 À6 mol of Pt per mol of CH¼ ¼CH 2 , when kinetics of PMDS formation was investigated. All reactions were carried out in bulk, with equimolar amounts of the reacting SiÀ ÀH and CH¼ ¼CH 2 groups. The course of the reactions was monitored by following the disappearance of the SiÀ ÀH bands using quantitative infrared spectroscopy. The results obtained showed typical first order kinetics for the PTMDSE formation, consistent with the proposed reaction mechanism. In the case of PMDS an induction period occurred at lower reaction temperatures, but disappeared at 44 8C and the rate of SiÀ ÀH conversion also started to follow the first-order kinetics.

This paper presents transformations of saturated hydrocarbons of petroleum type pollutants during ex situ bioremediation of soil on the pilot heap (halde), during a period of 6 months, within the grounds of Petroleum Refinery Pančevo (Serbia). Samples for analysis were taken in time intervals of 2 weeks (P 1 -P 12 samples). Organic substance was extracted by Soxhlet's method and quantified. Isoprenoid aliphatics, in particular pristane and phytane, and polycyclic aliphatics of sterane and triterpane types in saturated hydrocarbon fractions were analysed by GC-MS (SIM method). Significant amounts of n-alkanes have not been detected. The MSchromatogram revealed only marginal amounts of pristane and phytane in sample P 1 . Pristane and phytane occurred in sample P 8 , and in even higher quantities in the final sample P 12. The proceeding bioremediation process was accompanied by the decrease of the relative amounts of pentacyclic terpanes of hopane type, compared to tri-and tetracyclic terpanes. In the initial sample P 1 the distribution of steranes and hopanes follows a pattern, which is characteristic for crude oils. However, their identification by SIM method was not possible in samples P 8 and P 12 because of the reduced concentration. The observed changes in the alkane fractions' compositions may be considered as atypical, referring to the fact that during oil biodegradation under natural conditions, decomposition of isoprenoids occurs much easier and faster than decomposition of polycyclic alkanes of tri-, tetra-and pentacyclic terpane, sterane and diasterane types, after the decomposition of n-alkanes has been almost completed.

Basil essential oil (BEO) contains a wide range of chemical compounds whose content may vary depending on chemotypes, environmental conditions, agronomic techniques and particularly the origin of the plant. In our present study, essential oils (EOs) were isolated by hydrodistillation method from dry herbs of three basil cultivars and analyzed by GC-FID and GC-MS. Two of the tested cultivars belong to sweet basil group (B1 and B2) while the third one was large leafed ʽGenovese’ basil (B3). EO content in the dry herb was 0.65%, 0.41% and 0.62% respectively. The main classes of compounds of B1EO and B3EO were sesquiterpene hydrocarbons (38.39% and 37.95%), oxygenated monoterpenes (25.44% and 28.04%) and phenylpropanoids (17.43% and 15.71%). The main constituents of both EOs were monoterpene alcohol linalool (13.68% and 15.38%), phenoyl derivate eugenol (10.83% and 8.97%) and sesquiterpene hydrocarbon α-bergamotene (8.12% and 9.25%). In both EOs, epi-bicyclosesquiphellandrene was detected in considerable amount (7.03% and 8.07%). The most abundant compound classes in B2EO were oxygenated monoterpenes (52.07%), sesquiterpene hydrocarbons (24.27%) and phenylpropanoids (10.95%). Linalool was the dominant compound (40.97%), followed by epi-bicyclosesquiphellandrene (8.70%) and methyl chavicol (7.92%). The results showed complex chemical composition of BEOs and pointed out the presence of biologically active compounds of importance for different branches of the pharmaceutical, chemical and food industry. Although there are differences in the chemical composition of the BEOs, the obtained results show that all of the tested cultivars are rich in compounds which are responsible for biological activities.

Belgrade, capital city of Serbia, has over 1,600,000 inhabitants and over 400,000 vehicles trafficking every day on its streets. The investigation of soil pollution was performed by sequential extraction analysis to investigate the availability of potentially toxic metals (Zn, Cd, Pb, Co, Ni, Cu, Cr and Mn) under different oxidation and pH conditions. All investigated metals were mainly extracted from soils with neutral or acidic extractants. Serious pollution was observed along roads and streets with high traffic frequency, but Pb and Ni pollution was the highest since their concentrations exceed both soil Serbian standard and Canadian guidance values and is characteristic for all investigated sites. Cd, Cu, Cr and Zn concentrations are moderately high since they are between Canadian guideline and Serbian standard.