Electrochemical determination of selected pesticides in environmental water samples

Electrochemical detection of various contaminants has been widely used as a powerful tool in quality control of food and analysis of environmental samples. In this work, electrochemical procedures for determination of pesticides imidacloprid, metribuzin and metamitron are presented. Thin film layer electrode is used as a working electrode, while chronopotentiometry is applied as an electroanalytical technique. For all analysed pesticides, several solution conditions and instrumental parameters influencing the electroanalytical response of the analytes are examined and optimised in respect to the height of the analytical signals. The obtained analytical signals for the investigated pesticides are the result of irreversible reduction of the analyte on the working electrode surface, and for each analyte one reduction wave is obtained. Under the optimal experimental conditions, proposed chronopotentiometric methods are validated with the respect to linearity, limit of detection, limit of quantification, precision, selectivity, recovery and accuracy. Validated chronopotentiometric methods are applied for analysis of selected pesticides in spiked tap and river water samples. In the analysis of real samples, proposed methods showed to be sensitive and reproducible, fast (1-5 s analysis time), and simple since no complicated sample preparation is needed, and therefore are suitable for routine analysis of pesticides in water samples

Simple and rapid method for chronopotentiometric determination of metamitron in water samples and pesticide formulations

This paper describes chronopotentiontetrit method for determination of herbicide metamitron tising thin film mercury electrode and glassy carbon electrode as working electrodes. At both e working electrodes one well defined reductive peak appeared im Britton-Robinson butler

The influence of adding of flaxseed oil to sunflower oil on the content of tocopherols and carotenoids in blended edible oils

Blending vegetable oils of different composition and properties is one of the simplest methods for creating new specific products with the desired properties, which increases their commercial application and improves their nutritional quality. The effect of blending vegetable oils on tocopherols and carotenoids content was examined. Refined sunflower seed oil (S) and cold pressed flaxseed oil (F) were used in the experiment. These oils are blended in three different content of mass: sample 70S:30F (70% S and 30% F), sample 50S:50F (50% S and 50% F) and sample 30S:70F (30% S and 70% F). The results showed significant differences in the content of total tocopherols and total carotenoids between the two oils used for the preparation of three blended oils. Refined sunflower seed oil contains higher amounts of tocopherols and fewer amounts of carotenoids compared to cold pressed flaxseed oil in which the content of tocopherols is lower and the content of carotenoids is higher. In the obtained blends of edible vegetable oils, the content of total tocopherols ranged from 387.96 to 447.83 mg/kg while the determined total carotenoids content (as B-caroten) ranged from 3.11 to 5.63 mg/kg. By blending refined oil of sunflower seed and cold pressed oil of flax-seed, the balance of the parameters studied is contributed. The research in the work showed that the blending of vegetable oils provides the possibility of modulating their composition, and therefore of nutritive quality

Investigation of content of primary and secondary oxidation products in sunflower oils with a different content of oleic acid

Oxidative stability, i.c. shelf life of oil is related to the degree of the oxidative changes in the amount of the resulting primary and secondary oxidation products of unsaturated fatty acids. In order to improve oxidative stability, i.e. oil shelf life, sunflower hybrids with altered fatty acid composition have been created, i.e. significantly higher oleic acid (C18:1) content, even over 90% w/w, relative to the linoleic type with 25-30% w/w of oleic and 60-65% w/w of linoleic acid (C18:2). In order to examine the oxidative stability of the oil, three samples of sunflower seed oil NS hybrids (NS Oliva, NS Horizont and NS Romeo) of different fatty acid composition were analyzed. Samples were exposed to moderate temperatures (6342°C) over a period of 8 days. Changes in the content of primary and secondary oxidation products based on changes in peroxide (PV) and anisidine (p-AnV) values, as well as changes in the content of conjugated dienes and trienes, were observed. The highest oxidative stability was observed in the oleic type oil sample. In this sample the determined values of the tested parameters of oxidative stability, after 8 days, were PV=4.85 mmol/kg and p-AnV=0.65, compared to the initial sample (PV=0.36 mmol/kg and p-AnV=0.57). The greatest oxidative changes occurred in the oil sample with the lowest content of oleic and the highest content of linoleic acid, as indicated by the PV=73.22 mmol/kg and p-AnV=3.60, after 8 days, in relation to PV=2.16 mmol/kg and p-AnV=0.50 in the initial linoleic type oil sample

Effect of chitosan coating with the addition of caraway essential oil and beeswax on oxidative stability of petrovská klobása sausage

The aim of this paper was to examine the effect of chitosan coating with the addition of caraway essential oil and beeswax on lipid oxidation protection, as well as aroma and water content preservation of traditional dry fermented Petrovská klobása sausage. During the entire storage period, TBARS index value in coated sausage was lower compared to the control (P–1 and 0.66±0.03 mg kg–1, while after seven months of storage, these values were 0.82±0.05 mg kg–1 and 0.67±0.02 mg kg–1, respectively. While content of saturated aliphatic aldehydes increased in control sausage (P<0.05), it remained unchanged in coated sausage during 7 months of storage. Lipid oxidation protective effect could be correlated to higher marks for aroma of coated sausage during the entire storage period (P<0.05). Coating slowed moisture loss of coated sausage compared to the control (P<0.05)

Investigation of oxidative characteristics, fatty acid composition and bioactive compounds content in cold pressed oils of sunflower grown in Serbia and Argentina

In this work, the chemical composition analysis was performed for cold pressed oils obtained from the 15 sunflower hybrids grown in Serbia and Argentina, as well as the determination of their oxidative quality. The fatty acid composition and bioactive compounds including total tocopherols, phenols, carotenoids, and chlorophyll contents were investigated. The oxidation products were monitored through the peroxide value (PV), anisidine value (AnV), conjugated dienes (CD) and conjugated trienes (CT) content, and total oxidation index (TOTOX) under accelerated oxidation conditions by the oven method. Results: Linoleic acid was the most abundant fatty acid in investigated oil samples, followed by oleic and palmitic acids. The mean contents of total tocopherols, phenols, carotenoids, and chlorophyll were 518.24, 9.42, 7.54 and 0.99 mg/kg, respectively. In order to obtain an overview of sample variations according to the tested parameters Principal Component Analysis (PCA) was applied. Conclusion: PCA indicated that phenols, chlorophyll, linoleic and oleic acid were the most effective variables for the differentiation of sunflower hybrids grown in Serbia and Argentina. Furthermore, based on the fatty acid composition and bioactive compounds content in the oils, a new Artificial Neural Network (ANN) model was developed to predict the oxidative stability parameters of cold pressed sunflower oil

Comparative Study of the Nutritional and Chemical Composition of New Oil Rape, Safflower and Mustard Seed Varieties Developed and Grown in Serbia

Oilseed crops are widely cultivated and are related to nutrition and human health as valuable nutraceutical sources with valuable biological properties. The growing demand for oil plants used in human and animal nutrition or for the processing industry has contributed to the diversification and development of a new variety of oil crops. Increased oil crop diversity, besides ensuring reduced sensitivity to pests and climate conditions, has also led to improved nutritional values. In order to enable oil crop cultivation to become commercially sustainable, a comprehensive characterization of newly created varieties of oilseeds, including their nutritional and chemical composition, is required. In this study, two varieties of safflower and white and black mustard were investigated as alternative oil species for nutritional parameters, mainly protein, fat, carbohydrate, moisture, ash, polyphenols, flavonoids, chlorophylls contents, acids and mineral composition, and compared with those of two different genotypes of rapeseeds as a traditional oil crop plant. The proximate analysis found that the highest oil content was found in the oil rape NS Svetlana genotype (33.23%), while the lowest was in black mustard (25.37%). The protein content varies from around 26% in safflower samples to 34.63%, determined in white mustard. High content of unsaturated fatty acids and low content of saturated fatty acid was observed in the analyzed samples. In mineral analysis, the dominant elements were phosphorus, potassium, calcium and magnesium, in descending order. The observed oil crops are also good sources of microelements, including iron, copper, manganese and zinc, accompanied by high antioxidant activity due to the presence of significant amounts of polyphenolic and flavonoid compound