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GC-MS studies to map mechanistic aspects of photolytic decomposition of pesticides
11-16Views:99Transformation of pesticides in the environment is a highly complex process affected by different factors. Both biological and physical-chemical factors may play a role in the degradation, whose ratio depends on the actual environmental conditions.
Our study aims to reveal specific details of photolytic degradation of pesticides as important soil contaminants. Significance of these studies is enhanced by the fact that pesticide decomposition may contribute to soil degradation, and have harmful biological effects by degrading to toxic products. The toxicity of the examined pesticides is well known, however very little information is available regarding their natural degradation processes, the quality, structure and biological impact of the degradation products.
The photolytic degradation of frequently applied pesticides of distinctive types (acetochlor – acetanilide, simazine – triazine, chlorpyrifos – organophosphate, carbendazim – benzimidazole) was investigated. A special, immerseable UV-light source was applied in order to carry out photodegradation. The degradation processes were followed by thin layer chromatography (TLC) and mass spectrometry coupled with gas chromatography (GC/MS). EI mass spectrometry was used to identify the degradation species.
Each of the studied pesticides underwent photolytic decomposition, and the detailed mechanism of photolytic transformation was established. At least four degradation species were detected and identified in each case. Loss of alkyl, alkyloxy, amino-alkyl and chloro groups might be regarded as typical decomposition patterns. Deamination occurred at the last stage of decomposition. -
The effect of collecting area on the element content of Hungarian acacia honeys
129-138Views:225Six macroelements and twelve microelements were identified in thirty-six Hungarian acacia honeys collected from ten counties by inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS). One-Way ANOVA (LSD and Dunnett T3 test) and linear discriminant analysis (LDA) were used to determine the statistically verified differences among the honey samples with different geographical origin.
Significant differences were established among the samples from different counties in Na, P, S, Fe, Ni, Cu and Sr concentrations. Based on the macroelement content of honeys, the separation of samples with different geographical origin was not successful because the percent of correctly categorised cases was only 64.9%. However, examining the As, B, Ba, Cu, Fe Mn, Ni and Sr concentration, the separation of different groups was convincing since the percent of correctly classified cases was 97.2%. Thus, the examination of microelement concentration may be able to determine the geographical origin of acacia honeys.
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Parameter optimization of an inductively coupled plasma mass spectrometer for measuring arsenic and selenium
81-85Views:185In the last decades, an increased interest has evolved in arsenic and selenium. The aim is to understand the environmental, agricultural and biological roles of these elements. In the case of arsenic, the major reasons are the relatively high concentration of arsenic in marine biota (mg kg-1) and the arsenic contaminated drinking water bases of some Asian countries, as well as Hungary. The toxicity of higher level selenium content is also known; nevertheless, selenium is essential for several biological functions. Considering its essentialness, in our country, the insufficient selenium intake rate causes a lack of selenium. Measuring the concentrations of these elements provides crucial, but unsatisfactory information, as the speciation, i.e. the form of an element presented in a sample is also required.
In both cases, the most suitable method to determine concentration is inductively coupled plasma mass spectrometry (ICP-MS). Our objective was to optimize the variable parameters of the ICP-MS to attain the lowest (the best) detection limit. For this purpose, we investigated the effect of parameter change on net signal intensity and relative signal intensity. With the optimized parameter settings, the limits of detection for arsenic and selenium were determined, which are 0,032 ng dm-3 for arsenic, and 0,097 ng dm-3 for selenium. -
Selenium-speciation experiments from soil samples by accept of ionchromatography-inductively coupled plasma mass spectrometry (IC-ICP-MS) method
106-111Views:212In these days, selenium is one of the most investigated microelements. It has an important proven role in many vital processes. Selenium deficiency can play a role in the contraction of many diseases (e.g. cancer, heart diseases, etc.) and in the aggravation of their clinical aspect directly or indirectly. In this paper, we study the soil samples of an outdoor experiment for the conversion of the inorganic selenium salt that was spread out in different doses. The danger of the wash-out effect was also investigated. Our experiments showed, that most of the inorganic selenite transforms to selenate form during the years, and in this selenate form it moves to the deeper layers of soil.
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Selenium speciation analysis of selenium-enriched food sprouts
23-28Views:218In this present study, we prepared selenium-enriched pea and wheat sprouts. During our research we aimed not only to measure the total selenium content of the sprouts but to identify different selenium species.
Scientifical researches show why the analytical examination of different selenium (Se) species is necessary: consumption of all kind of Se-species is useful for a person who suffers in selenium deficit, while there is significant difference between effects of different Se-species on person, in whose body the Se-level is just satisfactory. Biological availability, capitalization, accumulation, toxicity of Se-species are different, but the main difference was manifested in the anti-cancer effect of selenium.
During our research selenium was used in form of sodium selenite and sodium selenate, the concentration of the solutions used for germination was 10 mg dm-3. Control treatment meant germination in distilled water. Total selenium content of sprout samples was measured after microwave digestion by inductively coupled plasma mass spectrometry (ICP-MS). Different extraction solvents were applied during sample preparation in order to separate different Se-species (0.1 M and 0.2 M HCl or 10 mM citric acid buffer). We wanted the following question to be answered: Which extraction solvent resulted the best extraction efficiency? Selenium speciation analysis of sprout sample extracts was performed by high performance liquid chromatography with anion exchange column, detection of selenium species was performed by ICP-MS.
Evaluating our experimental results we have been found that significant amount of selenium of inorganic forms used during germination transformed into organic selenium compounds. There was difference between the amount of Se-species in pea and wheat sprouts and selenium uptake and repartition of selenium species were depended on Se-form used during germination. In addition the chromatogram analysis made us clear as well, that the citric acid solvent proved to be the most effective extraction solvent during sample preparation int he view of organic Se species.
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HPLC-MS analysis of the active ingredients of chamomile (Matricaria chamomilla) bee feeding syrup
61-65Views:300Apiarists let prepare by bee honey products containing medicinal drugs. Our aim was to prove that the active ingredients originated from the herbs are also present in the bee products. This publication focuses only to the chamomile (Matricaria chamomilla) containing feeding syrup and the difference between the various syrup phases. To fulfil this task, we developed a method analysing the non-volatile components of the syrup using the flowers of chamomile. The method involves a filtration followed by HPLC-MS analysis. The analyses and the data evaluations proved that the non-volatile components of the herb were transferred to syrup. As the characteristic components of certain herbs could be identified also in the syrup, it is obvious that the components responsible for the medicinal effects are also transferred.
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Ragweed components in honey
65-68Views:189The aim of this research was to prove that the syrup containing ragweed used for feeding the bees was transferred to the honey. To reach this goal we developed a method to analyse the volatile components of the samples. We applied two sample preparation methods. The first one was SPME (Solid Phase Micro Extraction) preparation from the headspace of all of the samples. In the second case only the raw leaves of the ragweed were extracted with n-hexane and dichloromethane to complete the SPME results. The measurements were performed on GC-MS equipment. Chromatograms and data evolution showed that the components of the ragweed were also present in honey so they were transferred by bees.
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Comparative analysis of sample preparation methods to determine the concentration of arsenic in soil- and plant-samples
167-170Views:200Arsenic contamination of the fields and groundwater is a global problem. Alföld is the most affected area in Hungary. Irrigation witharsenic contaminated water, and crop production on the contaminated soil can cause a food safety problem, because arsenic is easy taken up by the cell of the plant roots. To prevent this, very important to monitoring the arsenic content of soils and plants. Inductively coupled plasma mass spectrometry (ICP-MS) is a fast, easy method to determined the concentration of minerals in the case of plant and soil samples The analytical methods can give reliable, results if the analytical process, including the sample preparation method, is the best. The objective of this study was to compare 3 type of sample preparation method which was dry ashing, wet digestion in open system, and microwave digestion. As a result of our experiement shows the microwave digestion is the appropriate method to determined the arsenic content of soil samples. In the case of plant samples we can use wet digestion in open system or microwave digestion as a samle preparation method.
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Effect of selenium supplement on proteome of chicken liver
9-13Views:161The aims of the present study were to optimize a two dimensional polyacrylamide gel electrophoresis method to chicken liver proteome and to determine the changes of protein expression caused by selenium. Twelve broiler chicken were used in this experiment. The selenium intake was 0,2 mg/kg in the control group (6 chicken) and 4,25 mg/kg in the experimental group (6 chicken). Using the optimized proteomic approach, we have succesfully separated 747 proteins in the experimental group and 741 proteins in the control group. We found six proteins, wich expressed only in the samples of experimental group. Further investigations need to determine these six proteins with mass spectrometry (MS) and look for the correlation between the physiological effects of selenium and the expression of these proteins.