Study of pesticide transformation processes in different wheat varieties and their effects on plant metabolism.

BACKGROUND: This study aims to obtain systematic understanding of the way by which pesticides are metabolized in plants and the influence of this process on plants' metabolism as this process has a key impact on plant-based food safety and quality. The research was conducted under field conditions, which enabled to capture metabolic processes taking place in plants grown under multihectare cultivation conditions. RESULTS: Research was conducted on three wheat varieties cultivated under field conditions and treated by commercially available preparations (fungicides, herbicides, insecticides, and growth regulator). Plant tissues with distinctions in roots, green parts, and ears were collected periodically during spring-summer vegetation period, harvested grains were also investigated. Sample extracts were examined by chromatographic techniques coupled with tandem mass spectrometry for: dissipation kinetics study, identification of pesticide metabolites, and fingerprint-based assessment of metabolic changes. CONCLUSION: Tissue type and wheat varieties influenced pesticide dissipation kinetics and resulting metabolites. Metabolic changes of plants were influenced by type of applied pesticide and its concentration in plants tissues. Despite differences in plant metabolic response to pesticide stress during cultivation, grain metabolomes of all investigated wheat varieties were statistically similar. 4-[cyclopropyl(hydroxy)methylidene]-3,5-dioxocyclo-hexanecarboxylic acid and trans-chrysantemic acid - metabolites of crop-applied trinexapac-ethyl and lambda-cyhalothrin, respectively, were identified in cereal grains. These compounds were not considered to be present in cereal grains up to now. The research was conducted under field conditions, enabling the measurement of metabolic processes taking place in plants grown under large-scale management conditions. © 2024 Society of Chemical Industry.

Non-target metabolomics approach for the investigation of the hidden effects induced by atrazine and its degradation products on plant metabolism.

Japanese radish (Raphanus sativus var. longipinnatus) plants grown under laboratory conditions were individually exposed to the same doses of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine, ATR) or its main degradation products: either 2-amino-4-chloro-6-isopropylamino-1,3,5-triazine (DEA) or 2-amino-4-chloro-6-ethylamino-1,3,5-triazine (DIA) or desethyl-desisopropyl-atrazine (DEDIA) or 4-(ethylamino)-2-hydroxy-6-(isopropylamino)-1,3,5-triazine (HA), respectively. One week after treatment in plants exposed to ATR, DIA, and DEA, their concentrations were 7.8 µg/g, 9.7 µg/g, and 14.5 µg/g, respectively, while those treated with DEDIA and HA did not contain these compounds. These results were correlated with plant amino acid profile obtained by suspect screening analysis and metabolomic "fingerprint" based on non-target analysis, obtained by liquid chromatography coupled with QTRAP triple quadrupole mass spectrometer. In all cases, both ATR and its by-products were found to interfere with the plant's amino acid profile and modify its metabolic "fingerprint". Therefore, we proved that the non-target metabolomics approach is an effective tool for investigating the hidden effects of pesticides and their transformation products, which is particularly important as these compounds may reduce the quality of edible plants.

Comprehensive multiresidue chromatographic methods for monitoring pesticides in agricultural areas and corresponding plant protection zones.

This article reports a comprehensive analytical method for the identification and quantification of a broad range of pesticides in green plant crops. The sample preparation method for pesticides involved an optimization of the QuEChERS-based extraction protocol, with sample mass, volume of added water, and the type of cleanup sorbent as variables. A sorbent combination based on ENVI-Carb and ChloroFiltr was examined. A highly efficient method was developed for the purification of plant extracts with 900 mg MgSO4, 150 mg PSA, and 15 mg ENVI-Carb at the d-SPE stage, combined with gas chromatography and liquid tandem mass spectrometry for the determination of 197 pesticides in crop plants containing chlorophyll. The method was validated in accordance with the requirements of international guidelines SANTE/11312/2021. The method was applied to quantify pesticide residues in 29 pairs of green crop plants and plants from the corresponding crop protection zone to verify whether the zones are effective barriers to prevent pesticides from penetrating outside agricultural areas. The number and types of agrochemical preparations were chosen by farmers. In total, more than 60 one- and several-component pesticide formulations were applied to the crops included in the study. The pesticide residues were detected in 21 crop samples and 3 samples from protection zones. Epoxiconazole, an active substance that was banned for use in 2021, was found in a spring barley sample. Based on the conducted research, the effectiveness of the protection zones has been clearly demonstrated, and it has been proven that environmental migration of pesticides and unauthorized agricultural practices pose a risk to ecosystems.

Metabolic profiling to evaluate the impact of amantadine and rimantadine on the secondary metabolism of a model organism.

Metabolic profiling offers huge potential to highlight markers and mechanisms in support of toxicology and pathology investigations during drug development. The main objective was to modify therapy with adamantane derivatives: amantadine and rimantadine, to increase their bioavailability and evaluate the influence of such therapy on drug metabolism using Saccharomyces cerevisiae as the model organism. In this study, the profile of endogenous metabolites of a model organism was measured and interpreted to provide an opportunity to investigate changes induced by treatment with amantadine and rimantadine. It was found that resveratrol supplementation synergistically enhanced the effects of amantadine treatment and increased rimantadine metabolism, potentially reducing side effects. The fingerprinting strategy was used as an efficient technique for qualitatively evaluating and monitoring changes in the profiles of endogenous components and their contents in a model organism. Chemometric tools were employed to find marker compounds that can be defined as characteristic indicators of a pharmacological response to a therapeutic intervention. An improved understanding of the mechanisms involved in drug effect and an increased ability to predict individual variations in the drug response of organisms will improve the treatment process and the development of new therapies.

The metabolic processes of selected pesticides and their influence on plant metabolism. A case study of two field-cultivated wheat varieties.

Pesticides that are absorbed by plants undergo biotransformation and might affect plant metabolic processes. The metabolisms of two cultivated wheat varieties, Fidelius and Tobak, treated with commercially available fungicides (fluodioxonil, fluxapyroxad, and triticonazole) and herbicides (diflufenican, florasulam, and penoxsulam) were studied under field conditions. The results provide novel insights regarding the effects of these pesticides on plant metabolic processes. Plants (roots and shoots) were sampled six times during the six-week experiment. Pesticides and pesticide metabolites were identified using GC-MS/MS, LC-MS/MS, and LC-HRMS, while root and shoot metabolic fingerprints were determined using non-targeted analysis. Fungicide dissipation kinetics were analyzed according to the quadratic mechanism (R2: 0.8522-0.9164) for Fidelius roots, and zero-order for Tobak roots (R2: 0.8455-0.9194); shoot dissipation kinetics were analyzed according to first-order (R2: 0.9593-0.9807) and quadratic (R2: 0.8415-0.9487) mechanisms for Fidelius and Tobak, respectively. The fungicide degradation kinetics were different compared to reported literature values, most likely due to differences in pesticide application methods. The following metabolites were respectively identified in shoot extracts of both wheat varieties for fluxapyroxad, triticonazole, and penoxsulam: 3-(difluoromethyl)-N-(3',4',5'-trifluorobiphenyl-2-yl)-1H pyrazole-4-carboxamide, 2-chloro-5-{(E)-[2-hydroxy-3,3-dimethyl-2-(1H-1,2,4-triazol-1-ylmethyl)-cyclopentylidene]-methyl}phenol, and N-(5,8-dimethoxy[1,2,4]triazolo[1,5-c]pyrimidin-2-yl)-2,4-dihydroxy-6 (trifluoromethyl)benzene sulfonamide. Metabolite dissipation kinetics varied depending on the wheat variety. These compounds were more persistent than parent compounds. Despite having the same cultivation conditions, the two wheat varieties varied in their metabolic fingerprints. The study revealed that pesticide metabolism has a greater dependence on plant variety and method of administration compared to the physicochemical properties of the active substance. This highlights the necessity of conducting research on pesticide metabolism under field conditions.

Metabolic profiles and fingerprints for the investigation of the influence of nitisinone on the metabolism of the yeast Saccharomyces cerevisiae.

Nitisinone (2-(2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione, NTBC) is considered a potentially effective drug for the treatment of various metabolic diseases associated with disorders of L-tyrosine metabolism however, side-effects impede its widespread use. This work aimed to broaden the knowledge of the influence of NTBC and its metabolites 2-amino-4-(trifluoromethyl)benzoic acid (ATFA), 2-nitro-4-(trifluoromethyl)benzoic acid (NTFA), and cyclohexane-1,3-dione (CHD) on the catabolism of L-tyrosine and other endogenous compounds in Saccharomyces cerevisiae. Based on a targeted analysis performed by LC-ESI-MS/MS, based on multiple reaction monitoring, it was found that the dissipation kinetics of the parent compound and its metabolites are compatible with a first-order reaction mechanism. Moreover, it has been proven that formed NTBC metabolites, such as CHD, cause a decrease in L-tyrosine, L-tryptophan, and L-phenylalanine concentrations by about 34%, 59% and 51%, respectively, compared to the untreated model organism. The overall changes in the metabolism of yeast exposed to NTBC or its derivatives were evaluated by non-targeted analysis via LC-ESI-MS/MS in the ion trap scanning mode. Based on principal components analysis, a statistically significant similarity between metabolic responses of yeast treated with ATFA or NTFA was observed. These findings facilitate further studies investigating the influence of NTBC on the human body and the mechanism of its action.

Targeted and non-targeted analysis for the investigation of pesticides influence on wheat cultivated under field conditions.

A comprehensive approach was applied to evaluate the effects of pesticides on the metabolism of wheat (Triticum aestivum L). The application of commercially available pesticide formulations under field cultivation conditions provided a source of metabolic data unlimited by model conditions, representing a novel approach to study the effects of pesticides on edible plants. Gas and liquid chromatography coupled to tandem mass spectrometry were employed for targeted and non-targeted analysis of wheat roots and shoots sampled six times during the six-week experiment. The applied pesticides: prothioconazole, tebuconazole, fluoxastrobin, diflufenican, florasulam, and penoxulam were found at concentrations ranging 0.0070-25.20 mg/kg and 0.0020-2.2 mg/kg in the wheat roots and shoots, respectively. The following pesticide metabolites were identified in shoots: prothioconazole-desthio (prothioconazole metabolite), 5-(4-chlorophenyl)-2,2-dimethyl-3-(1,2,4-triazol-1-ylmethyl)pentane-1,3-diol (tebuconazole metabolite), and N-(5,8-dimethoxy[1,2,4]triazolo[1,5-c]pyrimidin-2-yl)-2,4-dihydroxy-6-(trifluoromethyl)benzene sulphonamide (penoxulam metabolite). The metabolic fingerprints and profiles changed during the experiment, reflecting the cumulative response of wheat to both its growth environment and pesticides, as well as their metabolites. Approximately 15 days after the herbicide treatment no further changes in the plant metabolic profiles were observed, despite the presence of pesticide and their metabolites in both roots and shoots. This is the first study to combine the determination of pesticides and their metabolites plant tissues with the evaluation of plant metabolic responses under field conditions. This exhaustive approach contributes to broadening the knowledge of pesticide effects on edible plants, relevant to food safety.

Influence of nitisinone and its metabolites on l-tyrosine metabolism in a model system.

Nitisinone (NTBC) is currently used for the treatment of tyrosinemia type 1, a rare disease. It also exhibits potential in the treatment of other orphan diseases as well as nervous system disorders - this is however limited by its side effects. In all living organisms, NTBC inhibits 4-hydroxyphenylpyruvate dioxygenase activity, thereby affecting l-tyrosine (L-TYR) catabolism, which results in the therapeutic effect. The NTBC metabolites formed in patient's body is one of the causes of its side effects. The influence of NTBC and its metabolites; 2-amino-4-(trifluoromethyl)benzoic acid, 2-nitro-4-(trifluoromethyl)benzoic acid, and cyclohexane-1,3-dione on L-TYR catabolism was investigated in Raphanus sativus var. longipinnatus. Based on targeted LC-MS/MS analysis the concentration of NTBC and its metabolites in exposed plant tissues was determined. Based on non-targeted LC-MS/MS analysis the concentrations of products of L-TYR catabolism: levodopa, epinephrine, norepinephrine, normetanephrine, dopamine, tyramine and vitamins C, B5 and B6, additionally leucine and valine were identified as influenced by the NTBC or its metabolites. NTBC and its metabolites influenced L-TYR catabolism differently. Particularly significant changes were found in the content of epinephrine and normetanephrine: in the plant tissues exposed to NTBC, an increase in the content of these neurotransmitters was found (+42%), whereas in the plant treated with 2-amino-4-(trifluoromethyl)benzoic acid or 2-nitro-4-(trifluoromethyl)benzoic acid a decrease in concentration (-39% and 55%, respectively) was observed. Cyclohexane-1,3-dione does not influence epinephrine and normetanephrine concentration. The conclusions of this study provide a platform for expanded research on the causes of side effects of NTBC treatment.

ß-Cyclodextrin Derivative Grafted on Silica Gel Represents a New Polymeric Sorbent for Extracting Nitisinone from Model Physiological Fluids.

Nitisinone (NTBC) is used in the treatment of disorders affecting the tyrosine pathway, including hereditary tyrosinemia type I, alkaptonuria, and neuroblastoma. An inappropriate dosage of this therapeutic drug causes side effects; therefore, it is necessary to develop a rapid and sensitive method to monitor the content of NTBC in patients' blood. This study aimed to develop anew polymeric sorbent containing ß-cyclodextrin (ß-CD) derivatives grafted on silica gel to effectively extract NTBC from model physiological fluids. The inclusion complex formed between ß-CD and NTBC was examined by proton nuclear magnetic resonance spectroscopy. The novel sorbents with derivatives of ß-CD were prepared on modified silica gel using styrene as a comonomer, ethylene glycol dimethacrylate as a crosslinking agent, and 2,2'-azo-bis-isobutyronitrile as a polymerization initiator. The obtained products were characterized via Fourier transform infrared spectroscopy and then used as sorbents as part of a solid phase extraction technique. High NTBC recovery (70%indicated that the developed polymeric sorbent may be suitable for extracting this compound from patients' blood samples.

Metabolic profiles and non-targeted LC-MS/MS approach as a complementary tool to targeted analysis in assessment of plant exposure to pesticides.

Liquid chromatography coupled with tandem mass spectrometry was employed for the detection of pesticides (thiamethoxam, lambda-cyhalothrin, deltamethrin, and metalaxyl) and their metabolites in Raphanus sativus var. longipinnatus exposed to these compounds under experimental conditions. Metalaxyl (0.008 mg/kg), metalaxyl acid (0.009 mg/kg), and (+)-trans-chrysanthemic acid (0.098 mg/kg) were identified in the plants exposed to the individual pesticides and their metabolites. Non-targeted analysis revealed the presence of thiamethoxam, lambda-cyhalothrin, and deltamethrin metabolites in plants exposed to these substances, despite the fact that the pesticide concentrations were below the analytical method's limit of quantification (0.005-0.006 mg/kg). Based on the non-targeted screening, non-specific (leucine and tyramine) and specific (epinephrine, dopamine, tryptamine, and serotonin) markers of plant exposure to the mentioned stress-inducing compounds were detected. These findings prove that non-targeted analysis is an indispensable tool for determining plants' exposure to pesticides, even when the parent compound has been completely metabolized.

Profiling and fingerprinting strategies to assess exposure of edible plants to herbicides.

Raphanus sativus var. longipinnatus, was exposed under experimental conditions to herbicides: rimsulfuron (RIM), administrated as (1) pure substance, (2) in commercially available formulation (RIMEL), (3) its degradation product: 4,6-dimethoxypyrimidin-2-amine (2ADP), (4) mesotrione (MES), (5) sulcotrione (SUL). Profiling and fingerprinting strategies, conducted by LC-MS/MS-FL, were employed to find markers of plant exposure to herbicide stress. The presence ofRIM metabolite in the tissues of plant exposed to this herbicide proved that it is necessary to determine both parent compound and its by-products to obtain reliable information on plant exposure to agrochemicals. A higher content of normetanephrine (NMN) (18-175%) and lower content of tyramine (TYR) (49-75%) and epinephrine (E) (75-83%) was observed in plant tissues exposed to RIM and 2ADP in comparison to blank sample. Therefore, NMN, TRY and E may be considered as markers of plant response to RIM. Non-target analysis enables to recognize the type of herbicide used during cultivation.

Rapid MSPD-LC-MS/MS Procedure for Determination of Pesticides in Potato Tubers.

The program of potato protection recommended by the producers of agrochemicals requires application: thiamethoxam, lambda-cyhalothrin, deltamethrin, rimsulfuron and metalaxyl. Therefore, there is a risk that these pesticides are present in tubers, thus posing a toxicological risk to the consumer. In this respect, it is necessary to monitor the presence of these compounds in edible plants. Therefore, the aim of this paper was to develop a novel, simple and robust analytical procedure for simultaneous determination of above-mentioned pesticides in potato tubers. To develop an analytical procedure that fulfills SANTE demands, quick, easy, cheap, effective, rugged and safe method and matrix solid phase dispersion technique were investigated. The final determination was conducted by liquid chromatography with tandem mass spectrometry. The obtained experimental data were analyzed by analysis of variance. For the extraction of analytes, matrix solid phase dispersion with octadecyl sorbent and methanol as eluent was chosen, since it provides the validation parameters according to SANTE requirements (recovery: 77-111%, relative standard deviation: 1-10%, limit of quantification: 0.9-5.0 µg/kg). This innovative analytical procedure is a practical analytical tool, which was successfully proven by applying it for target pesticides determination in potato tuber samples of different varieties randomly chosen at local markets.

Metabolic profiles in the course of the shikimic acid pathway of Raphanus sativus var. longipinnatus exposed to mesotrione and its degradation products.

The influence of pesticides on the metabolism of edible plants has not been fully investigated. Moreover, once introduced into the environment, pesticides are degraded to many compounds with undefined bioactivity. In presented work, under experimental conditions, model edible plant (Raphanus sativus var. longipinnatus) was exposed to herbicide stress by application of a herbicide (mesotrione, 2-(4-methanesulfonyl-2-nitrobenzoyl)cyclohexane-1,3-dione, MES) or its degradation products (amino-4-(methylsulfonyl)benzoic acid, AMBA; 4-(methylsulfonyl)-2-nitrobenzoic acid MNBA; cyclohexane-1,3-dione, CHD). Metabolic profiles of plants were employed to estimate the plant's defence response to MES and its metabolites. The intensity of herbicide stress was determined by measuring the changes in chlorophyll and catecholamines concentration formed in the shikimic acid pathway. Non-target analysis was conducted by LC-MS/MS, determination of catecholamines by LC-FL, chlorophyll by spectrophotometry. The highest phytotoxicity is characterized by MES (2000%-fold increase in the content of herbicide stress marker (normetanephrine) compared to a blank), followed by CHD (500%) combined with 15% increase in chlorophyll concentration. AMBA and MNBA as stress factors caused the increase in the content of catecholamines in the plant (86-160%). Simultaneously, an increase in chlorophyll content was observed (26-50%). Such diversity of the organism's defence response, also visible on metabolic profiles, can be associated with the chemical structure of compounds that are stress factors. MES and CHD, in contrast to AMBA and MNBA, have cyclohexano-1,3-moiety in their structure, which seems to be responsible for herbicidal properties.

Potential application of Pistia stratiotes for the phytoremediation of mesotrione and its degradation products from water.

The aim of the present work is to estimate remediation potential of Pistia stratiotes, its ability to uptake mesotrione (MES) - one of the most frequently used herbicides, and its main degradation products: 2-amino-4-methylsulfonyl benzoic acid (AMBA) and 4-methylsulfonyl-2-nitrobenzoic acid (MNBA). This research focuses on model experiments performed under laboratory conditions. The results show that Pistia stratiotes can uptake up to 75% of degradation products from 1 L of surface water samples polluted with 0.4 µg/L of each analyte during 7 days without significant phytotoxic effect. Under the same experimental conditions, the effectiveness of mesotrione sorption is in the range of 42-58%. The phytotoxicity of this compound is higher in comparison to its degradation products (decrease of chlorophyll concentration in plant tissues exposed to MES 27-32% vs 4-13% in case of exposition to AMBA and MNBA). The adequate nutrition of the plants is crucial to their well-being and thus the sorption of pollutants.

LC-MS/MS study of the degradation processes of nitisinone and its by-products.

Nitisinone (2-(2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione, NTBC) was the first synthetically produced triketone herbicide. However, its unsatisfactory herbicidal properties, negative impact on the natural environment and the high cost of synthesis have hindered its commercialization as a plant protection agent. Nevertheless, NTBC has become the medical treatment of choice for a rare hereditary metabolic disease -hepatorenal tyrosinemia. Literature review shows that most research on nitisinone focuses on its medical applications, while there are neither in-depth studies of its stability nor its degradation pathways. Therefore, the aim of our study was to employ liquid chromatography coupled with mass spectrometry (LC-MS/MS) to determine the stability of NTBC in different experimental conditions (pH of solution, temperature, time of incubation, ultraviolet radiation), identify its degradation products and determine the stability of the latter. Electrospray ionization (ESI) in the negative ion mode was used as an ionization method and the analytes were detected by multiple reaction monitoring. We show that nitisinone stability increases with increasing pH of the solution. At pH similar to that of gastric juice in the human stomach, two major products of NTBC degradation are formed: 2-amino-4-(trifluoromethyl)benzoic acid (ATFA) and 2-nitro-4-(trifluoromethyl)benzoic acid (NTFA), which show considerable stability under studied conditions. The results of these studies shed new light on the properties of NTBC, therefore contributing to better understanding of possible risks and benefits of its medical application.

Review of Sample Preparation Techniques for the Analysis of Selected Classes of Pesticides in Plant Matrices.

The aim of this article is to present the trends in extraction techniques applied for the isolation of pesticides from plant matrix. To fully compare the effectiveness of different extraction techniques, it was required to analyze compounds with possibly wide spectrum of physicochemical properties. Hence, compounds representing neonicotinoids, pyrethroids, sulfonylureas and phenylamides were selected. Based on literature studies, it may be concluded that there are three main approaches to make the analytical procedures for pesticides determination more effective: (i) the optimization of extraction conditions, however, according to ANOVA conducted on the collected literature data, not all parameters influence the extraction process equally; chemometric studies based on literature reports may lead to the conclusion that the most favorable conditions (criterion: analyte recovery, repeatability) for neonicotinoid, pyrethroid and sulfonylurea herbicide extraction from plant tissues are provided by QuEChERS - extraction with acetonitrile, while the mixtures of PSA and GCB (for neonicotinoids), and PSA, GCB, C18 (for pyrethroids) should be used in d-SPE step. For sulfonylurea compounds and metalaxyl it was impossible to identify a sorbent(s) that cleans up the extract more effectively than the others; (ii) to develop a new generation of sorbents; however, the range of their applicability is limited, mainly due to difficulties in their synthesis; (iii) to develop the new extraction techniques with as few "trouble spots" as possible.

Atrazine, triketone herbicides, and their degradation products in sediment, soil and surface water samples in Poland.

The aim of this study was to monitor the sediment, soil and surface water contamination with selected popular triketone herbicides (mesotrione (MES) and sulcotrione(SUL)), atrazine (ATR) classified as a possible carcinogen and endocrine disrupting chemical, as well as their degradation products, in Silesia (Poland). Seventeen sediment samples, 24 soil samples, and 64 surface water samples collected in 2014 were studied. After solid-liquid extraction (SLE) and solid phase extraction (SPE), analytes were determined by high-performance liquid chromatography (HPLC) with diode array detection (DAD). Ten years after the withdrawal from the use, ATR was not detected in any of the collected samples; however, its degradation products are still present in 41 % of sediment, 71 % of soil, and 8 % of surface water samples. SUL was determined in 85 % of soil samples; its degradation product (2-chloro-4-(methylosulfonyl) benzoic acid (CMBA)) was present in 43 % of soil samples. In 17 % of sediment samples, CMBA was detected. Triketones were detected occasionally in surface water samples. The chemometric analysis (clustering analysis (CA), single-factor analysis of variance (ANOVA), N-Way ANOVA) was applied to find relations between selected soil and sediment parameters and herbicides concentration. In neither of the studied cases a statistically significant relationship between the concentrations of examined herbicides, their degradation products and soil parameters (organic carbon (OC), pH) was observed.

Extraction procedures for the study of phytotoxicity and degradation processes of selected triketones in a water ecosystem.

Simple and effective extraction methods based on matrix solid-phase dispersion (MSPD), dispersive liquid-liquid microextraction (DLLME), and solid-phase extraction (SPE) coupled with high-performance liquid chromatography with diode array detector (HPLC-DAD) were developed to determine triketone herbicides-sulcotrione (SUL), mesotrione (MES), tembotrione (TEMB), and their degradation products-in plant tissues and water samples. The extraction procedures were employed to enable quantification of the accumulation of selected triketone herbicides and their degradation products in a model aquatic plant, Egeria densa. To obtain comprehensive information about the triketones' influence on an aquatic plant, changes in chlorophyll concentration in plants exposed to these triketones were monitored. The average recovery ranged from 58 to 115 % (coefficients of variation 7-12 %) for plant tissues and from 52 to 96 % (coefficients of variation 8-20 %) for water samples. The limit of detection (LOD) for the MSPD-HPLC-DAD procedure was in the range of 0.06-0.23 µg/g, whereas for DLLME-HPLC-DAD and SPE-HPLC-DAD, LOD was in the range of 0.06-0.26 µg/mL. Symptoms of the phytotoxicity of sulcotrione, mesotrione, tembotrione, and their degradation products (decrease of chlorophyll concentration in plant sprouts) were observed for E. densa cultivated in water with herbicide concentrations of 100 µg/L. Moreover, the tembotrione degradation product exhibited a high level of accumulation and low metabolism in plant tissues in comparison to the other triketones and their degradation products.

Monitoring of atrazine in milk using a rapid tube-based ELISA and validation with HPLC.

Although atrazine has been banned in the European Union since 2007 it still persists in soil from where it can enter the food chain. Milk-producing animals accumulate atrazine from contaminated feed and water and since large quantities of milk and milk products are consumed its quality should be constantly monitored. The objective of this investigation was to develop a simple tube ELISA procedure suitable for use in non-specialised laboratories and in the field. A polyclonal antibody raised in sheep and the hapten-gelatine conjugate was immobilised onto polystyrene tubes. This enables the colour produced to be read on a basic spectrophotometer. Milk samples were collected from three farms in different regions of Poland and diluted before immunoassay was performed. Samples were extracted with hexane-acetone for HPLC analysis. The amount of fat in the milk samples interferes with the dose response so it essential that the standards are prepared in the same samples matrix. A good correlation between 1% and 2% was found between the two methods in the analysis of real samples. However the ELISA procedure was more sensitive that the HPLC method since atrazine was detected in some samples by the ELISA but was not confirmed by the HPLC method. The study demonstrated that the simple antigen-coated tube assay provides a cost effective and valuable screening test that can be easily modified for direct use as a screening tool in the field.

New procedures for simultaneous determination of mesotrione and atrazine in water and soil. Comparison of the degradation processes of mesotrione and atrazine.

A method for the determination of residues of mesotrione, atrazine and its degradation products: deethylatrazine, hydroxyatrazine, deisopropylatrazine, desethyldesisopropylatrazine in a variety of water and soil matrices has been developed. Mesotrione is a new selective herbicide for use in corn, which has been substituted for atrazine, which has been banned in European Union countries since 2007. Although atrazine has not been used for three vegetative periods, it is still detected in the environment. The analysis was conducted by means of ultra-high-pressure liquid chromatography with ultraviolet detection and liquid chromatography with diode array detection. The procedures for analyte separation from water and soil matrices were also established. The optimal conditions for solid-phase extraction (SPE) were determined. The recoveries were compared with that obtained by means of SPE. Method fortification recoveries from water samples averaged 78-97% and for soil 80-97% depending on the analyte and type of sample. The limits of detection were 0.04-0.61 µg/L for water samples and for soil samples 0.02-0.88 µg/g. The soil samples were collected in spring 2009 from three different fields with water samples being made from effluents from these fields. Samples collection was conducted in the day of mesotrione (Callisto 100SC) application and then done weekly, until the mesotrione concentration was below the limit of quantification. The results enabled the monitoring of mesotrione degradation in soil and its permeability into surface waters; simultaneously, the same studies were conducted for atrazine.