Papers by Vesna Stankov Jovanovic
The aim of this paper is to determine the efficiency of D-µ-SPE with application of novel sorbent... more The aim of this paper is to determine the efficiency of D-µ-SPE with application of novel sorbents as a technique for sample preparation of water samples for the analysis of 16 priority PAHs by GC-MS. The sample preparation technique proved to be very fast, efficient and economical. The results of the proposed method demonstrate that this technique can be applied for routine analysis of PAHs in water. The advantages of this method are characterized by low values of limit of detection (from 0.147 ppb for benzo [a] anthracene to 0.784 ppb for naphthalene) and the limit of quantification (0.717 ppb for naphthalene to 9.459 ppb for benzo [k] fluorantene.Ciljevi istraživanja ovog rada su određivanje efikasnosti disperzivne mikroekstrakcije čvrstom fazom (D-µ-SPE) kao tehnike pripreme uzoraka vode za analizu 16 prioritetnih PAU gasnom hromatografijom sa masenom spektrometrijom, primenom novih sorbenasa. Tehnika pripreme uzoraka pokazala se kao veoma brza, efikasna i ekonomična. Rezultati ...
Metals, whether from natural and anthropogenic sources, can migrate between different parts of th... more Metals, whether from natural and anthropogenic sources, can migrate between different parts of the environment and accumulate in flora and fauna, and in this way can finally reach people through the food chain. The possibility of contamination of plants by metals limits their use both in the pharmaceutical and food industry, because the increased concentration of some metals can have a negative impact on the health of humans and animals. The medicinal herbaceous species Seseli pallasii Besser is used in traditional medicine, but also as a spice in nutrition, so the assessment of the presence of metals is essential to ensure its safe application. For the estimation of the contents of the micro (Al, B, Ba, Co, Cu, Fe, Mn, V, Zn) and macroelenates (Ca, K, Mg and Na) in vegetative parts of plant species Seseli pallasii Besser (root, leaf, flower and fruit) from Southeast Serbia the method of induced coupled plasma with optical emission spectrometry (ISP-OES) was applied. The content of ...
Journal of Applied Polymer Science
Chemical Industry, 2020
Biperiden, an antiparkinsonian anticholinergic drug, has been found to inhibit enzymatic hydrolys... more Biperiden, an antiparkinsonian anticholinergic drug, has been found to inhibit enzymatic hydrolysis of butyrylthiocholine iodide, which is catalyzed by serum cholinesterase. By measuring the difference in the basic and inhibitory hydrolysis reaction rates, in the presence of biperiden as an inhibitor, it is possible to develop a kinetic method for its determination. Both systems, enzyme-substrate-chromogen and enzyme-substrate-chromogen-inhibitor, were characterized by biochemical parameters (KM = 0.326 ? 0.330 mmol dm-3; Vmax = 40 - - 99 ?mol dm-3 min-1), while inhibition was defined as non-competitive with the constant of inhibition Ki = 6.142 ?mol dm-3. The reaction conditions have been optimized followed by determination of the calibration curve, the corresponding equation and the limits of detection and quantification yielding 3.84 and 12.80 nmol dm-3, respectively. Using the calibration chart, it is possible to determine biperiden in different samples in the concentration rang...
Journal of Essential Oil Bearing Plants, 2020
Abstract The essential oil isolated from aerial parts of Hypericum rumeliacum Boiss. was analyzed... more Abstract The essential oil isolated from aerial parts of Hypericum rumeliacum Boiss. was analyzed by GC and GC/MS. Forty three identified compounds accounted for 98.8 % of the total oil. The main components of the oil were: (E)-β-ocimene (18.2 %), β-pinene (14.7 %), (Z)-β-ocimene (13.0 %), dodecanal (7.4 %) germacrene D (5.8 %) and myrcene (5.8 %). The volatile profile of H. rumeliacum was characterized by a large content of monoterpene hydrocarbons (68.2 %), followed by non-terpenoids (14.4 %) and sesqiuterpenoids (11.8 %). Multivariate statistical analyses (agglomerative hierarchical cluster analysis and principal component analysis) were used to compare and discuss interrelationship within the mentioned species based on essential oil profiles. The oil was tested in a broth microdilution assay against five bacterial and two fungal strains and found to have mainly moderate antimicrobial effects.
Journal of Food and Nutrition Research, Jan 23, 2013
Effect of food preparation technique on antioxidant activity and plant pigment content in broccol... more Effect of food preparation technique on antioxidant activity and plant pigment content in broccoli, Brussels sprouts, white cabbage, kale, chard, spinach and garden patience were studied. The highest content of chlorophyll a was detected in garden patience (0.837 mg/g f.v.) and the lowest was in brussels sprout (0.047 mg/g f.v.), while chlorophyll b and carotenoid content was lower. Boiling had influence on pigment content in selected vegetables. Different food preparation technique showed influence on antioxidant activity of vegetables extracts. Boiled vegetables extracts showed highest antioxidant activity, which indicates that valuable phytochemicals remains in water during cooking process. Highest reducing power is detected for frozen garden patience extract (16.775 AAE/10 g f.v.), while DPPH, ABTS and FRAP assays showed highest antioxidant activities for boiled and microwave cooked vegetables. Correlations among antioxidant activities based on ABTS, DPPH, FRAP and TRP assays were positively high and r ranged between 0.68 and 0.99.
A possibility of a new application (chemically and thermally modified natural zeolites-clinoptilo... more A possibility of a new application (chemically and thermally modified natural zeolites-clinoptilolit) as potential adsorbers of organic material from waste water (which was a result of dying wool with acid dyes) was investigated. It has been concluded that the best results were obtained by using the zeolite modification (in which the ratio Si/Al=5,02, thermally treated at 573 K) at pH 5. The content of organic substances in waste water was reduced by 69% for that modification.
Journal of pharmaceutical and biomedical analysis, Jan 27, 2015
Extracts of different polarity obtained from various plant parts (root, leaf, flower and fruit) o... more Extracts of different polarity obtained from various plant parts (root, leaf, flower and fruit) of Seseli rigidum were studied by different antioxidant assays: DPPH and ABTS radical scavenging activity, by total reducing power method as well as via total content of flavonoids and polyphenols. Essential oils of all plant parts showed weak antioxidant characteristics. The inhibitory concentration range of the tested extracts, against bacteria Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, and fungi Candida albicans and Aspergillus niger was 0.01-1.50mg/mL and of a microbicidal 0.02-3.00mg/mL. In the interaction with cholinesterase, all essential oils proved effective as inhibitors. The highest percentage of inhibition versus human and horse cholinesterase was shown by root essential oil (38.20% and 48.30%, respectively) among oils, and root hexane extract (40.56% and 50.65% respectively). Essential oils and volatile components of all plant parts were...
Acta chimica Slovenica, 2012
In vitro antioxidant activity of two cyclodidepsipeptides, 3-(2-methylpropyl)-6-(propan-2-yl)-4-m... more In vitro antioxidant activity of two cyclodidepsipeptides, 3-(2-methylpropyl)-6-(propan-2-yl)-4-methyl-morpholine-2,5-dione and 3,6-di(propan-2-yl)-4-methyl-morpholine-2,5-dione, was investigated. Our data indicate moderate antioxidant potentials of the two studied cyclodepsipeptides. A high correlation between 2,2-diphenyl-1-picrylhydrazyl (DPPH)-radical scavenging capacity and total reducing power were found. According to the density functional theory (DFT) calculations, the most probable mechanism of antioxidant action is hydrogen atom abstraction from the activated C-H group at 3-position in the morpholinedione ring. To the best of our knowledge this is the first report about the antioxidant properties of morpholine-2,5-diones derivatives.
Analytical Letters, 2015
ABSTRACT The elemental composition of four wild edible mushroom species were determined by induct... more ABSTRACT The elemental composition of four wild edible mushroom species were determined by inductively coupled plasma optical emission spectrometry (ICP OES): scotch bonnet (Marasmius oreades), chanterelle (Cantarellus cibarius), porcini (Boletus edulis) and peppery milk-cap (Lactarius piperatus). Mushrooms are a potassium-rich food, which was confirmed in this study. M. oreades contained the highest concentration of almost all elements, except for cadmium, potassium, phosphorus, and lead. Lead and cadmium were present but at concentrations that are not hazardous to human health. A principal component analysis loading plot for elemental composition demonstrated that 95.51 percent of the total variance was present in the first two principal components. Cluster analysis separated the elements into three statistical significant clusters.
Oxidation Communications
Cited By (since 1996):2, Export Date: 18 October 2014
Hemijska industrija, 2013
Primary role of peroxidase enzyme is to decompose endogenous hydrogen peroxide, when oxygen radic... more Primary role of peroxidase enzyme is to decompose endogenous hydrogen peroxide, when oxygen radical is being replaced by a less potent radical, which is its cosubstrates oxidized form. During this study, catalytic activity of horseradish peroxidase has been observed in the presence of antioxidants from vitamin group, such as C, E and A, i.e. their water-soluble forms. It was found that vitamin E showed no effect on the enzyme activity and fate of cosubstrate radicals from the group of benzidine derivatives. Vitamin C proceeds enzymatic reaction showing its antioxidative character, and absorbs electrons from radicals, bringing cosubstrate back to its relaxed state. On the other hand, vitamin A plays a role of uncompetitive peroxidase inhibitor, which is visible through decreasing initial rate of catalytic reaction, and is reflected as virtual decrease of enzyme concentration. Furthermore, it prolongs life of endogenous hydrogen peroxide, which could potentially lead to oxidative stre...
Hemijska industrija, 2015
The aim of this study was to evaluate heavy metal content in carrots (Daucus carota) from the dif... more The aim of this study was to evaluate heavy metal content in carrots (Daucus carota) from the different localities in Serbia and to assess by the cluster analysis (CA) and principal components analysis (PCA) the heavy metal contamination of carrots from these areas. Carrots were collected at 13 locations in five districts. Chemometric methods (CA and PCA) were applied to classify localities according to heavy metal content in carrots. CA separated localities into two statistical significant clusters. PCA permitted the reduction of 12 variables to four principal components explaining 79.94% of the total variance. The first most important principal component was strongly associated with the value of Cu, Sb, Pb and Tl. This study revealed that CA and PCA appear as useful tools for differentiation of localities in different districts using the profile of heavy metal in carrot samples.
Chemical Industry, 2012
Propranolol, a widely used beta-blocker, inhibits the reaction of enzyme cholinesterase hydrolysi... more Propranolol, a widely used beta-blocker, inhibits the reaction of enzyme cholinesterase hydrolysis. Measurements of the hydrolysis rate differences between and inhibited reactions, allows the development of a kinetic method for its determination. Both systems, enzyme-substrate-chromogen and enzyme-substrate-chromogen-inhibitor, were characterized through biochemical kinetic parameters (KM = 0.326-0.330 mmol/L; Vmax = 40-42.99 ?mol/Lmin), inhibition type was recognized as competitive, and inhibition constant, Ki, was determined to be 22.60 ?mol/L. The detection and quantification limits were calculated as 0.004 and 0.0136 ?mol/L, respectively. Accuracy and precision of proposed methods were tested. Proposed method is characterized with good sensitivity, selectivity, simplicity and rapidity, thus it is convenient for clinical applications.
Environmental Earth Sciences, 2014
The aim of this work was to examine the consequences of the wildfire on the differences in qualit... more The aim of this work was to examine the consequences of the wildfire on the differences in qualitative and quantitative composition of the soil, and Cu, Pb, Cd, and Zn levels in the soils and plant species of Geraniaceae family at Vidlic Mountain, Serbia. Main soil characteristics organic matter content, conductivity, redox potential, pH (H 2 O), pH (KCl), and chloride content in soil samples from post-fire areas and from fire non-disturbed areas were studied. The optimized three-step sequential extraction procedure was applied to the analysis of Cu, Pb, Cd, and Zn levels in the soils. Distribution of heavy metals in aerial parts and roots of examined species was investigated too. For some characteristic parameters of soil, like conductivity, redox potential, chloride content, the impact of fire on the soil habitats followed the same trend for all plants species. Content of copper, lead, and zinc in plant material derived from post-fire areas was generally greater than their content in the plants that grew on the area not exposed to fire. Although the content of cadmium was generally higher in all fractions of the samples from the locality not exposed to the fire, content of that metal in the plant parts was reversed. Most characteristics of soil are significantly altered as a consequence of fire. Majority of soil samples from the post-fire area had increased content of analyzed metals, except cadmium. Fire caused slightly increased bioavailability of the examined metals. The biggest difference in the content of the studied metals in the soil from the post-fire areas and the area not exposed to fire was in the fraction which includes metals associated with organic matter.
Journal of the Serbian Chemical Society, 2005
Anew sensitive kinetic method has been developed for the determination of trace amounts of phenyl... more Anew sensitive kinetic method has been developed for the determination of trace amounts of phenylhydrazine in the range of 1.08x10-7 to 1.08x10-6 g/cm3. The detection limit of this method is 0.008 ?g/cm3, based on the 3Sb criterion. Themethod is based on the inhibitory effect of phenylhydrazine on the oxidation of Victoria Blue 4-R by KBrO3. The reaction was monitored spectrophotometrically at 596.3 nm. The method development includes the optimization of the reagent concentration and temperature. The kinetic parameters of the reaction are reported and a rate equation is suggested. The effects of certain foreign ions upon the reaction rate were determined for the assessment of the selectivity of the method. The new developed method was found to have fairly good selectivity, sensitivity, simplicity and rapidity.
Journal of Mass Spectrometry, 2012
Azaphilones represent numerous groups of wild fungal secondary metabolites that exhibit exception... more Azaphilones represent numerous groups of wild fungal secondary metabolites that exhibit exceptional tendency to bind to nitrogen atoms in various molecules, especially those containing the amine group. Nitrogenized analogues of mitorubrin azaphilones, natural secondary metabolites of Hypoxylon fragiforme fungus, have been detected in the fungal methanol extract in very low concentrations. Positive electrospray ionization interfaced with high-resolution mass spectrometry was applied for confirmation of the elemental composition of protonated species. Collision-induced dissociation (CID) experiments have been performed, and fragmentation mechanisms have been proposed. Additional information regarding both secondary metabolite analogue families has been reached by application of gas-phase proton/deuterium (H/D) exchanges performed in the collision cell of a triple quadrupole mass spectrometer. An incomplete H/D exchange with one proton less than expected was observed for both protonated mitorubrin azaphilones and their nitrogenized analogues. By means of the density functional theory, an appropriate explanation of this behavior was provided, and it revealed some information concerning gas-phase H/D exchange mechanism and protonation sites.
Journal of Essential Oil Research, 2011
Journal of Clinical Laboratory Analysis, 2007
A modification of the existing spectrophotometric kinetic method for the determination of pancuro... more A modification of the existing spectrophotometric kinetic method for the determination of pancuronium bromide (PCBr), based on pooled human serum cholinesterase (ChE, EC 3.1.1.8 acylcholine acylhydrolase) inhibition, was developed. Butyrylthiocholine iodide (concentration 1.667 mmol/L) was used as substrate and determination was performed at pH 7.6. Essential basic kinetic parameters were also determined: Michaelis-Menten's constant K M 5 0.33 mmol/L, maximal reaction rate V max 5 42.29 mmol/ L min, inhibition constant K I 5 0.34 mmol/L, and IC 50 5 0.235 mmol/L. Linear dependence between the reaction rate and the inhibitor concentration exists in PCBr concentration range 8.29-265.28 nmol/L, which corresponds to the real sample concentrations from 0.166 to 5.306 mmol/L. The method detection limit was established to be 1.86 nmol/L and the quantification limit was 6.18 nmol/L. Precision of the method was tested for three pancuronium concentrations (16.58, 99.48, and 198.96 nmol/L). The relative standard deviation (RSD) was in the range 0.78-5.13%. Accuracy was examined by the standard addition method. The influence of substances usually present in serum and urine on the reaction rate was determined. The method developed was applied for PCBr determination in spiked serum and urine samples and in the urine taken during surgery. The method was proven to have good sensitivity, accuracy, and precision and can be considered suitable for clinical practice.
Uploads
Papers by Vesna Stankov Jovanovic