Pesticide Preparations Research Articles

Respiratory and non-respiratory symptoms associated with pesticide management practices among farmers in Ghana's most important vegetable hub.

The data presented here are from the Offinso North District Farm Health Study (ONFAHS), a population-based cross-sectional study among vegetable farmers in Ghana. The paper addresses knowledge, pesticide handling practices, and protective measures related to pesticide use by self-reported symptoms for 310 adult farmers who completed a comprehensive questionnaire on pesticide management practices and health. In addition, an inventory was prepared using information supplied by pesticide sellers/dealers in this district. We report that cough and wheezing (but not breathlessness) are positively associated with stirring pesticide preparations with bare hands/drinking water while mixing/applying pesticides, and stirring pesticide preparations with bare hands/drinking water/smoking cigarettes while mixing/applying pesticides. There is a significant exposure-response association between the number of precautionary measures practiced while handling pesticides and cough and wheezing but not with breathlessness. We also found unsafe practices to be associated with sexual dysfunction, nervousness, and lack of concentration. The results also suggest a negative association between practice of any precautionary measure when mixing/applying pesticides and sexual dysfunction, nervousness, and lack of concentration. We found that in spite of the fact that farmers have adequate knowledge about the environment and health effects of pesticides, several unhygienic practices are in widespread use, indicating that knowledge is not necessarily always translated in action. Further action is necessary to promote the safe use of pesticides and to replace existing poor management practices among these and other farmers in Ghana.

The improvement of methodical approaches of hygienic regulation of pesticides in water bodies

The article highlights the methodical features of hygienic regulation of pesticide preparation in water bodies, concretizes and supplements (specified) number of positions of the acting current methodical document on hygienic evaluation of new pesticides. From the position of the comprehensive hygienic standardization there are marked principles of the study of MPC for pesticides in water bodies, there is substantiated the expediency of expanding the arsenal of methods for determination of threshold concentrations of pesticides on the impact on organoleptic properties of water and sanitary regime of reservoirs, shows the role and importance of hydrolysis processes of active ingredients ofpesticides in water, which should be considered in the assessment of the impact of drugs on the processes of self-purification of water bodies.

Tailor-Made Specific Recognition of Cyromazine Pesticide Integrated in a Potentiometric Strip Cell for Environmental and Food Analysis.

Screen-printed ion-selective electrodes were designed and characterized for the assessment of cyromazine (CYR) pesticide. A novel approach is to design tailor-made specific recognition sites in polymeric membranes using molecularly imprinted polymers for cyromazine (CR) determination (sensor I). Another sensor (sensor II) is the plasticized PVC membrane incorporating cyromazine/tetraphenyl borate ion association complex. The charge-transfer resistance and water layer reached its minimal by incorporating Polyaniline (PANI) solid-contact ISE. The designed electrodes demonstrated Nernstain response over a linear range 1.0 × 10−2–5.2 × 10−6 and 1.0 × 10−2–5.7 × 10−5 M with a detection limit 2.2 × 10−6 and 8.1 × 10−6 M for sensors I and II, respectively. The obtained slopes were 28.1 ± 2.1 (r2 = 0.9999) and 36.4 ± 1.6 (r2 = 0.9991) mV/decade, respectively. The results showed that the proposed electrodes have a fast and stable response, good reproducibility, and applicability for direct measurement of CYR content in commercial pesticide preparations and soil samples sprayed with CYR pesticide. The results obtained from the proposed method are fairly in accordance with those using the standard official method.

Оцінка екотоксичності пестицидів з використанням тваринних тест-організмів

The following article is the result of biotesting of ecotoxicological danger of pesticides, which are used in gardening. Ten pesticide preparations were selected for the research, six of them are fungicides: flint-star, chorus, score, stroby, topsin-M and median-extra and four of them are insecticides: bi-58, calypso, mospilan and actara. Toxicity of pesticides was identified through analyzing ten times dilution (1:10) of the recommended solution specified by the manufacturer. Not less than three days old tap water served as control. Daphnia, Ostracoda and Danio were selected as test objects. After 1, 2, 3, 4, 5, 24 and 72 hours of exposure the number of dead animals was visually determined and the percentage of survival of testers was calculated. The toxicity of the pesticide preparations was considered as proven if the percentage of test organisms mortality rate was ≥50%. The scale of pesticide toxicity degree was developed, including the percentage of test organisms mortality during certain exposure time (up to 24 or 48 hours). It can be used to define its acute and toxic effect. According to the biotesting results, flint-star and score are the most toxic among the examined pesticide preparations fungicides for aquatic ecosystems, as they showed ultrahigh and high levels of toxicity for zootests. Carp fishes of the genus Danio showed greater sensitivity to the influence of fungicides and lower to insecticides, while for aquatic crustaceous Daphnia and Ostracoda these features were not detected. The sensitivity of the tested test objects to insecticides decreased in an order: Ostracoda sp.→Daphnia sp.→Danio sp. Comparing the sensitivity of aquatic crustaceous in the process of the pesticides biotesting, it was found out that Ostracoda sp. is more sensitive test object than Daphnia sp. Under the same conditions of biotesting, an absolute immobilization of ostracods is two times higher than the immobilization of Branchiopoda.

The mutagenicity and carcinogenicity of pesticides and hazards for human health: A systematic review

The article presents concise review of data obtained during last years at studying mutagenic and carcinogenic activity of pesticides in test-systems in vitro and in vivo Also, are covered the results of epidemiological surveys carried out in Russia and abroad related to discovery of association of effect of pesticides and development of oncological diseases in workers involved into agricultural manufacturing and in population of rural regions. The publications search was implemented using databases of Scopus, Medline, Google Scholar, RINTC. The issues are discussed concerning evaluation of mutagenic characteristics of effecting substances and preparative forms ofpesticides, application of short-term tests for evaluating carcinogenicity, possible synergy effects in case of combination of two and more effecting substances of various pesticide preparations.

Reduction behavior of insecticide azoxystrobin and its voltammetric determination using silver solid amalgam electrode

Electrochemical reduction of systemic fungicide azoxystrobin, used to protect a wide variety of crops, was investigated using cyclic voltammetry with a mercury meniscus-modified silver solid amalgam electrode (m-AgSAE). The mechanism of the electrochemical reduction was proposed and supported with high-performance liquid chromatography/mass spectrometry analysis of azoxystrobin solutions electrolyzed on mercury pool electrode. An analytical method for the determination of azoxystrobin by differential pulse voltammetry with m-AgSAE was developed. A wide linear dynamic range (2.0 × 10−6–5.0 × 10−5 mol dm−3) and low limit of detection (7 × 10−7 mol dm−3) were obtained. The accuracy and repeatability of the proposed method were evaluated by the analysis of model solutions with recovery from 96.0 to 104.0% and relative standard deviation of 5 repeated determinations < 3.5%. Finally, a new voltammetric method using m-AgSAE was successfully applied for azoxystrobin determination in real samples, concretely in spiked river water and pesticide preparations.

Green pesticides based on cinnamate anion incorporated in layered double hydroxides and dispersed in pectin matrix

This paper reports the preparation of green pesticides based on nano-hybrids composed of a Layered Double Hydroxide (LDH) with cinnamate anion. The dispersion into a pectin matrix was obtained using high energy ball milling in wet conditions. Structure and physical properties of the fillers and the composites films were evaluated. Controlled release of cinnamate was followed using UV spectrophotometry and the release kinetics were found to be dependent on the filler loading. The experimental results were analyzed by the Gallagher-Corrigan model. Antimicrobial activity was evaluated on different bacterial strains, as well as plant pathogens belonging to the genus Phytophthora using modified agar diffusion, broth microdilution and dual culture methods, respectively. Experimental results suggested the possibility to use the analyzed composites as green protective coatings for crops’ protection.

Oxidation Behavior of Insecticide Azoxystrobin and its Voltammetric Determination Using Boron‐doped Diamond Electrode

AbstractElectrochemical oxidation of azoxystrobin, a systemic fungicide commonly used in agriculture to protect a wide variety of crops, was investigated using cyclic voltammetry with a boron‐doped diamond electrode (BDDE) in aqueous buffer solutions. Two pH independent irreversible anodic current peaks controlled mostly by diffusion were observed in wide pH range (2 to 12) at potentials +1600 mV and +2150 mV vs. saturated silver‐silver chloride electrode. Mechanism of the electrochemical oxidation was proposed and supported with high performance liquid chromatography/mass spectrometry analysis of azoxystrobin solutions electrolyzed on carbon fiber brush electrode. The main product of the first two‐electron oxidation step was identified as methyl 2‐(2‐{[6‐(2‐cyanophenoxy)pyrimidin‐4‐yl]oxy}phenyl)‐2‐hydroxy‐3‐oxopropanoate. An analytical method for the determination of azoxystrobin in water samples and pesticide preparation by differential pulse voltammetry with BDDE was developed. The method provides a wide linear dynamic range (3.0×10−7 to 2.0×10−4 mol L−1) with limit of detection 8×10−8 mol L−1. Accuracy of the method was evaluated by the addition and recovery method with recoveries ranging from 96.0 to 105.8 %. Interference study proved sufficient selectivity of the developed voltammetric method for the azoxystrobin determination in presence of azole fungicides as well as pesticides used to prevent the same crops.

ENVIRONMENTAL SAFETY MANAGEMENT OF SUBSTANDARD PESTICIDE RESIDUES AND REMEDIATION AND RECLAMATION OF CONTAMINATED SOIL

In Ukraine, there is still a great number of unused, unidentified and substandard pesticide preparations (PPs) and other toxic substances which have an extremely dangerous impact on humans and other living ecosystems and the environment. Besides, more than 75 thousand tons of pesticides are imported and produced annually in Ukraine, but some of them are not used during the period of their suitability. Consequently, when stored mostly in dilapidated warehouses and repositories of agrochemicals, as well as in the open areas, they fall into underground and ground water, and then through trophic chains into the organisms of living systems, causing severe poisoning and diseases. We note that till now, the problem of unsuitable PPs was solved only in the context of their utilization or export for processing outside the state, while the rest of this ecological problem – the restoration of soils and the remediation of contaminated lands at the state level, is not virtually solved. Therefore, the substantiation of the scientific and practical aspects of environmental safety management of such remediation processes is on time.

Comparison of QuEChERS with Traditional Sample Preparation Methods in the Determination of Multiclass Pesticides in Soil.

Background: The increased use of pesticides leads to permanent pollution of soil, and there is a need for continuous monitoring of these agrochemicals in soil. Objective: Three methods for the simultaneous determination of 12 pesticides belonging to eight chemical groups in soil samples were tested and compared based on analytical parameters. Methods: The quick, easy, cheap, effective, rugged, and safe (QuEChERS); traditional solid-liquid extraction (SLE); and Soxhlet extraction were used for soil sample preparation, while detection and quantification of pesticides were performed using gas chromatography-mass spectrometry (GC-MS). Results: The tested methods featured good sensitivity, and with the exception for carbofuran (Soxhlet method, LOD = 29 μg/kg), for the rest of the pesticides, the studied LODs were less than 12 μg/kg. Except for simazine and carbofuran, LODs obtained by Soxhlet extraction were lower than values obtained by other two methods, whereas QuEChERS gave lower LODs than the traditional SLE method for all compounds except atrazine and acetochlor. The recoveries obtained applying QuEChERS, traditional SLE, and Soxhlet methods for multiple analyses of soil samples fortified at 10, 75, and 200 μg/kg of each pesticide were in the ranges 54-103, 40-91, and 12-92%, respectively. Except for chlorothalonil, the highest recoveries were obtained by the QuEChERS method. Soxhlet was better than traditional SLE method for chlorothalonil, heptachlor, and aldrin; organophosphorus pesticides (fenitrothion and diazinon) and trifluralin, gave similar recoveries for both methods. All three methods were proven to be repeatable, with RSDs lower than 19%. Conclusions: Although all tested methods showed as satisfactory regarding most analytical parameters, QuEChERS method showed much better results in terms of confidence, indicating that traditional SLE and Soxhlet extraction still need improvements for determination of multiclass pesticides in soil samples.

THE APPLICATION OF THE MATHEMATICAL MODEL FOR PREDICTING THE THRESHOLD CONCENTRATIONS OF THE INFLUENCE OF PESTICIDES ON THE SANITARY STATUS OF WATERS

Introduction. The rapid growth in the production and use of pesticides poses a real risk of the possible contamination of water bodies, which determines the urgency of the improving the methods of hygienic rating of pesticide preparations in water bodies, as well as the search for screening methods for establishing threshold concentrations.The issues of the need to improve the methodological approaches to the hygienic regulation of pesticide products in water of water bodies are considered, the need for further scientific study of this issue is shown. Material and methods. There are presented results of ourselves laboratory studies on the effect of herbicides of the sulfonylurea class on the processes of self-purification of reservoirs according to the Biological Oxygen Demand (BOD) index. In the work there were used substances of the sulfonylureas derivatives with a multi-directional mechanism of action that exerts both a stimulating and inhibitory effect on the course of processes of the biochemical oxygen consumption. With the use of the formula (Gotovtsev A.V., 2016), the total biochemical oxygen consumption for sulfonylurea derivatives was calculated from the two experimentally measured BOD values. Results. The data of biochemical oxygen consumption for two substances, obtained as a result of experimental studies, are presented. Selected substances have a multi-directional effect on the course of biochemical processes: stimulation - deviation of BOD from the control (%); inhibition - deviation of BOD from the control (%). There was made an estimation of the possible use of the formula for calculating the total biochemical oxygen consumption obtained in the solution of the modified Streeter-Phelps equation system for pesticides of the sulfonylurea class. The formula was applied as a mathematical model for the predictive assessment of the establishment of threshold concentrations of pesticides on the effect on the sanitary regime of water bodies (accordingly to BOD index). Discussion. In the paper, experimental and calculated values of biochemical oxygen consumption were compared, which shows the possibility of using this mathematical method for predicting the effect of pesticidal preparations of this class on the processes of self-purification of water reservoirs. Conclusion. There was shown the possibility of using mathematical modeling methods, in particular, the modified Streeter-Phelps system of equations in the practice of sanitary and hygienic investigations.

Проблема оцінки гематотоксичності пестицидів

Introduction. The article presents the results of studies of hematoxicity of pesticides, which at the present stage acquire special significance in connection with the widespread use of pesticides. The obtained data testify to the need for laboratory monitoring of the effectiveness and safety of the use and accumulation of pesticides in the environment and in humans and animals, therefore they justify the urgency of preventing side effects of pesticide preparations. The author came to the conclusion that when carrying out hematological studies with a diagnostic purpose, it is necessary to take into account the changes that arise in the blood system under the influence of potential toxicants, including drugs. In order to prevent hematotoxic effects, pharmacotherapy should strictly adhere to metered regimens and regimens.The need to study the state of the blood system is dictated, first of all, by its importance for maintaining the constancy of the internal environment of the organism and the risk of the emergence of various pathological conditions when the functioning of the blood system is disturbed. It is especially important to note the relevance of differential diagnosis of blood damage and diseases that occur with lymphoproliferative and autoimmune syndromes. Taking this into account, it is necessary to note the importance of differential diagnosis of leukemoid reactions arising from exposure to potential toxicants.The current state of control of the side effects of pesticides does not provide an opportunity to objectively assess the significance of the problem of medicinal and pesticidaltoxicoses and the post-toxication complications caused by them, including the risk of hematotoxic effects. The potential risk of hematotoxic complications is the violation of the basic functions of the blood.The aim of the study – to note the importance of research and a deeper study of the processes that arise when the blood system is exposed to potentially dangerous chemicals (XP) and leads to the development of hematological dysfunctions.Conclusions. The effect of substances of various groups of pesticides on the blood system was established, violations of hematological parameters of peripheral blood and their connection with morphological indices under conditions of exposure to potential toxicants were revealed, which is of fundamental importance in the diagnosis of hematotoxic effects.

TOXICOLOGICAL CHARACTERISTICS OF MODERN PESTICIDES USED IN THE SYSTEM OF STRAWBERRIES CHEMICAL PROTECTION. REVIEW

Relevance. The strawberries are consumed mostly fresh, that is why the toxicological assessment of chemical protection formulations applied on strawberries is compulsory before its entering the market.&#x0D; Objective: toxicological characteristics of modern pesticides used in the system of strawberries chemical protection.&#x0D; Materials and methods. Aktara 25 WG, inc., Switch 62.5 WG, Force 1.5 G, G, Nuprid 600 TN, and Torero SC pesticide preparations containing thiamethoxam, cyprodinil, fludioxonil, tefluthrin, imidacloprid, methamitron, and ethofumezate were the materials of the toxicological evaluation conducted according to the data of literary and official Internet sources.&#x0D; Results. A analysis of the literature on the toxic properties of the studied pesticides and its active ingredients used to protect strawberries has been carried out and the classes of hazard were established according to the current Ukrainian hygienic classification of pesticides.&#x0D; Conclusion. Switch 62.5 WG, Force 1.5 G, G, Nuprid 600 TN, and Torero SC pesticide preparations and fludioxonil, cyprodinil and metamitron active ingredients are classified according to acute inhalation toxicity as limiting criterion to the second integral hazard class (moderately hazardous), and Aktara 25 WG, preparation and thiamethoxam – to third integral hazard class (hazardous), active substances imidacloprid, tefluthrin, ethofumezate – to the first integral hazard class (extremely hazardous).

Bazı Sık Kullanılan Organofosfatlı Pestisitlerin Anne Sütünde Kalıntılarının Belirlenmesi

Objectives: There is limited data on levels of organophosphorus pesticides (OPPs) in humans, but no previous reports from Turkey on chemically determined levels of OPP residues in human milk are present. The aim of this study is to determinate and to report the presence of residues of OPPs, which are frequently used in fruit production in the study area (chlorpyrifos, diazinon, ethion, parathion methyl and dichlorvos) in breast milk. Materials and Methods: In this cross-sectional study, breast milk samples were collected from 100 women living in intense fruit production area (agricultural area, n:50), and resided in provincial center (urban area, n:50), selected by random sampling method. High resolution analyses were performed by a gas chromatography (GC). Results: Dichlorvos residue was detected in breast milk of 17% of study group. The rate of pesticide residue detection was especially high in breast milk of women with a farmer spouse; always/frequently applying pesticides to the plants, actively working in agriculture pesticide preparation and pesticide application (p<0.05). Conclusion: Pesticide residues were detected in breast milk and this showed the necessity of raising consciousness among women living in the study area and near areas of pesticide application about avoiding exposure to pesticides, especially during pregnancy and breast feeding periods.

Knowledge, awareness and practices of workers exposed to pesticides in Qatar

Background: Pesticide poisoning is a global public health problem. With growing population and rapid industrialisation in Qatar, there has been a natural increase in pesticide usage and hence, exposure amongst the workers handling them. It is therefore vital to understand existing knowledge, attitudes and practices about handling pesticides. Methods: 100 municipality employees in Qatar who work with pesticides, were interviewed in person by trained bilingual staff using a structured questionnaire model. Results: The mean age of the workers was 37.4 (SD-9.9) Of the interviewed workers, 81% did not know the contents or the name of the pesticides they were handling at work. Unsafe behaviours such as preparation of pesticides at the site of its usage rather than in a specified preparation room (29.6%), non-compliance with wearing protective clothing (38.8%), handling of drinking water (22%) and food (10%) on site where pesticides are used and not washing clothes every day after work (45.9%) were observed. Workers who received training in pesticides usage were more likely to be aware of its effects on the environment (61.6%) (OR-3.9), less likely to eat or drink while handling pesticides (83.6%) (OR-4.3) and more likely to give household members appropriate instructions prior to application of pesticides (90.4%) (OR-5.0). Workers who did not wear special protective clothes at work were found to be, more than twice as likely to visit hospitals per year, than those who wore (RR-2.2). Conclusion: Unsafe practices were found to be significantly common amongst the personnel using pesticides. Workers who received prior training handled pesticides in a safer way.

Evaluation of Isotopic Abundance Ratio in Biofield Energy Treated Nitrophenol Derivatives Using Gas Chromatography-Mass Spectrometry

Nitrophenols are the synthetic organic chemicals used for the preparation of synthetic intermediates, organophosphorus pesticides, and pharmaceuticals. The objective of the present study was to evaluate the effect of biofield energy treatment on the isotopic abundance ratios of PM+1/PM, and PM+2/PM in o- and m-nitrophenol using the gas chromatography-mass spectrometry. The o- and m-nitrophenol were divided into two parts - one part was control sample, and another part was considered as biofield energy treated sample, which received Mr. Trivedi’s biofield energy treatment (The Trivedi Effect® ). The biofield energy treated nitrophenols having analyzed at different time intervals were designated as T1, T2, T3, and T4. The GCMS analysis of both the control and biofield treated samples indicated the presence of the parent molecular ion peak of o- and mnitrophenol (C6H5NO3 + ) at m/z 139 along with major fragmentation peaks at m/z 122, 109, 93, 81, 65, and 39. The relative peak intensities of the fragmented ions in the biofield treated o- and m-nitrophenol were notably changed as compared to the control sample with respect to the time. The isotopic abundance ratio analysis using GC-MS revealed that the isotopic abundance ratio of PM+1/PM in the biofield energy treated o-nitrophenol at T2 and T3 was significantly increased by 14.48 and 86.49%, respectively as compared to the control sample. Consequently, the isotopic abundance ratio of PM+2/PM in the biofield energy treated sample at T2 and T3 was increased by 11.36, and 82.95%, respectively as compared to the control sample. Similarly, in m-nitrophenol, the isotopic abundance ratio of PM+1/PM in the biofield energy treated sample at T1, T3, and T4 was increased by 5.82, 5.09, and 6.40%, respectively as compared to the control sample. Subsequently, the isotopic abundance ratio of PM+2/PM at T1, T2, T3 and T4 in the biofield energy treated m-nitrophenol was increased by 6.33, 3.80, 16.46, and 16.46%, respectively as compared to the control sample. Overall, the isotopic abundance ratios of PM+1/PM (2H/1H or 13C/12C or 15N/14N or 17O/16O), and PM+2/PM (18O/16O) were altered in the biofield energy treated o- and m-nitrophenol as compared to the control increased in most of the cases. The biofield treated o- and m-nitrophenol that have improved isotopic abundance ratios might have altered the physicochemical properties and could be useful in pharmaceutical and chemical industries as an intermediate in the manufacturing of pharmaceuticals and other useful chemicals for the industrial application.

Evaluation of Isotopic Abundance Ratio in Biofield Energy Treated Nitrophenol Derivatives Using Gas Chromatography-Mass Spectrometry

Nitrophenols are the synthetic organic chemicals used for the preparation of synthetic intermediates, organophosphorus pesticides, and pharmaceuticals. The objective of the present study was to evaluate the effect of biofield energy treatment on the isotopic abundance ratios of PM+1/PM, and PM+2/PM in o- and m-nitrophenol using the gas chromatography-mass spectrometry. The o- and m-nitrophenol were divided into two parts - one part was control sample, and another part was considered as biofield energy treated sample, which received Mr. Trivedi’s biofield energy treatment (The Trivedi Effect®). The biofield energy treated nitrophenols having analyzed at different time intervals were designated as T1, T2, T3, and T4. The GC-MS analysis of both the control and biofield treated samples indicated the presence of the parent molecular ion peak of o- and m-nitrophenol (C6H5NO3+) at m/z 139 along with major fragmentation peaks at m/z 122, 109, 93, 81, 65, and 39. The relative peak intensities of the fragmented ions in the biofield treated o- and m-nitrophenol were notably changed as compared to the control sample with respect to the time. The isotopic abundance ratio analysis using GC-MS revealed that the isotopic abundance ratio of PM+1/PM in the biofield energy treated o-nitrophenol at T2 and T3 was significantly increased by 14.48 and 86.49%, respectively as compared to the control sample. Consequently, the isotopic abundance ratio of PM+2/PM in the biofield energy treated sample at T2 and T3 was increased by 11.36, and 82.95%, respectively as compared to the control sample. Similarly, in m-nitrophenol, the isotopic abundance ratio of PM+1/PM in the biofield energy treated sample at T1, T3, and T4 was increased by 5.82, 5.09, and 6.40%, respectively as compared to the control sample. Subsequently, the isotopic abundance ratio of PM+2/PM at T1, T2, T3 and T4 in the biofield energy treated m-nitrophenol was increased by 6.33, 3.80, 16.46, and 16.46%, respectively as compared to the control sample. Overall, the isotopic abundance ratios of PM+1/PM (2H/1H or 13C/12C or 15N/14N or 17O/16O), and PM+2/PM (18O/16O) were altered in the biofield energy treated o- and m-nitrophenol as compared to the control increased in most of the cases. The biofield treated o- and m-nitrophenol that have improved isotopic abundance ratios might have altered the physicochemical properties and could be useful in pharmaceutical and chemical industries as an intermediate in the manufacturing of pharmaceuticals and other useful chemicals for the industrial application.

ОЦІНКА ЯКОСТІ ВИРОБНИЧОГО СЕРЕДОВИЩА ПРИ ЗАСТОСУВАННІ НОВИХ ПЕСТИЦИДНИХ ПРЕПАРАТІВ

ОЦІНКА ЯКОСТІ ВИРОБНИЧОГО СЕРЕДОВИЩА ПРИ ЗАСТОСУВАННІ НОВИХ ПЕСТИЦИДНИХ ПРЕПАРАТІВ

Sensitive voltammetric method for determination of herbicide metribuzin using silver solid amalgam electrode

New sensitive voltammetric method for determination of triazinone herbicide metribuzin (MTZ) was developed employing polished and mercury meniscus-modified silver solid amalgam electrode (p-, m-AgSAE). MTZ yielded two reduction signals on both used working electrodes in acidic and slightly acidic media and the positively situated peak [at about −650 mV vs. Ag|AgCl|KCl (sat.)] was found suitable for further analytical measurements. The highest responses were recorded in Britton–Robinson buffer of pH 2 (p-AgSAE) or 3 (m-AgSAE). Various voltammetric techniques like cyclic, linear sweep, and differential pulse voltammetry were used for examination of the voltammetric behavior of MTZ. Parameters of differential pulse voltammetry were optimized and low detection limits were reached (LODm-AgSAE = 6.0 × 10−8 mol dm−3 and LODp-AgSAE = 7.5 × 10−8 mol dm−3). Moreover, excellent repeatability of determination and measurements as well was confirmed by low values of relative standard deviations of five repeated determinations [RSD (5) ≤ 6.0 %] and of 11 repeated measurements [RSD (11) ≤ 4.5 %], respectively. Finally, practical applicability of newly proposed methods was verified by the analysis of spiked tap and river water and by determination of MTZ in pesticide preparation with excellent results. All the obtained results were compared with those gained for classic mercury electrode.

Voltammetric Behavior of the Insecticide Pymetrozine on a Mercury Meniscus Modified Silver Solid Amalgam Electrode

ABSTRACTA novel sensitive voltammetric method for the determination of the insecticide pymetrozine was designed using a solid working electrode. A mercury meniscus modified silver solid amalgam electrode in connection with differential pulse voltammetry was found to be appropriate for the determination of the insecticide. Pymetrozine provided one well-developed reduction peak suitable for analytical purposes at approximately −800 millivolts (vs. the Ag/AgCl electrode) in an acidic medium. The voltammetric behavior of pymetrozine as a function of the pH of the supporting electrolyte and scan rate was investigated using cyclic voltammetry and direct current voltammetry, respectively. The optimum conditions for determination using differential pulse voltammetry were in a Britton-Robinson buffer at pH 3.0 with a limit of detection of 5.4 × 10−8 moles per liter and a linear dynamic range from 2 × 10−7 to 1 × 10−4 moles per liter. The relative standard deviations of repeated determinations (n = 5) at various concentrations of pymetrozine did not exceed 3%. The results obtained using a silver solid amalgam electrode were compared with those achieved on hanging mercury drop electrode. The influence of possible interfering agents was also studied. The practical application of the method was verified by analysis of pesticide preparations and fortified river water.