Looking beyond the Active Substance: Comprehensive Dissipation Study of Myclobutanil-Based Plant Protection Products in Tomatoes and Grapes Using Chromatographic Techniques Coupled to High-Resolution Mass Spectrometry

Tracing the dissipation of difenoconazole, its metabolites and co-formulants in tomato: A comprehensive analysis by chromatography coupled to high resolution mass spectrometry in laboratory and greenhouse trials

The study evaluated Ceremonia 25 EC®, a plant protection product (PPP) containing difenoconazole, in tomato crops, to identify potential risks associated with PPPs, and in addition to this compound, known metabolites from difenoconazole degradation and co-formulants present in the PPP were monitored. An ultra high performance liquid chromatography coupled to quadrupole-Orbitrap mass analyser (UHPLC-Q-Orbitrap-MS) method was validated with a working range of 2 μg/kg (limit of quantification, LOQ) to 200 μg/kg. Difenoconazole degradation followed a biphasic double first-order in parallel (DFOP) kinetic model in laboratory and greenhouse trials, with high accuracy (R2 > 0.9965). CGA-205374, difenoconazole-alcohol, and hydroxy-difenoconazole metabolites were tentatively identified and semi-quantified in laboratory trials by UHPLC-Q-Orbitrap-MS from day 2 to day 30. No metabolites were found in greenhouse trials. Additionally, 13 volatile co-formulants were tentatively identified by gas chromatography (GC) coupled to Q-Orbitrap-MS, detectable up to the 7th day after PPP application. This study provides a comprehensive understanding of difenoconazole dissipation in tomatoes, identification of metabolites, and detection of co-formulants associated with the applied PPP.

Monitoring of Volatile Additives from Plant Protection Products in Tomatoes Using HS-SPME-GC-HRMS: Targeted and Suspect Approaches

Additives present in plant protection products (PPPs) are normally not monitored after sample treatments. In this study, the fate of additives detected by targeted and nontargeted analysis in tomato samples treated with two PPPs was carried out. The study was carried out in a greenhouse for 12 days, in which two applications with each PPP were made. Compounds were extracted by applying a headspace solid phase microextraction (HS-SPME) and analyzed by gas chromatography coupled to high resolution mass spectrometry (GC-HRMS), performing targeted and suspect approaches. Three targeted and 15 nontargeted compounds were identified at concentration levels of up to 150 μg/kg. Compounds detected encompassed benzene, toluene, indene, and naphthalene derivatives, as well as conservatives and flavouring compounds. Most of them degraded in less than 7 days after the second application, following first-order kinetic. This study aims to reduce knowledge gaps regarding additives and their fate under real climatic conditions of greenhouses cultivations.

Residues of pesticide co-formulants in lettuce and parsley: Identification of decline processes using field trials in different cropping systems

BACKGROUND

Although co-formulants constitute a substantial portion of the total plant protection product (PPP) mass applied to crops, data on residue formation and the behaviour of these substances on plants are scarce. In an earlier study we demonstrated that co-formulants commonly used in PPPs can form considerable residues, i.e., in the low to medium mg/kg range, but normally decline rapidly within few days. In the field trial reported here, we aimed to identify the major decline processes of co-formulants. Residues of co-formulants were therefore monitored in parsley and lettuce grown in an open field as well as under foil tunnels equipped with either an overhead or a drip irrigation system.

RESULTS

Dissipation of three anionic surfactants was markedly faster when crops (parsley and lettuce) were exposed to natural rainfall or irrigation from above compared to drip irrigation. In contrast, the decline of three volatile organic solvents was not affected by rain or irrigation, but was dependent on the crop, with much shorter half-lives in lettuce than in parsley. Furthermore, dilution through plant growth contributed significantly to the reduction of residues over time.

CONCLUSION

In this work we substantiate earlier findings on the magnitude and dissipation of residues of anionic surfactants and solvents representing the most important co-formulant classes. The chosen experimental setup allowed differentiation between decline processes and we confirm that foliar wash-off is a major dissipation process for anionic surfactants. For volatile organic solvents, dissipation appears to depend on the properties not only of the substance but also of the plant (surface). © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Uncovering the Dissipation of Chlorantraniliprole in Tomatoes: Identifying Transformation Products (TPs) and Coformulants in Greenhouse and Laboratory Studies by UHPLC-Q-Orbitrap-MS and GC-Q-Orbitrap-MS

The present study addressed the dissipation of the insecticide chlorantraniliprole in tomatoes treated with Altacor 35 WG under laboratory and greenhouse conditions, as well as the identification of transformation products (TPs) and coformulants, performing suspect screening analysis. Analyses were performed by ultra-high-performance liquid and gas chromatography coupled to quadrupole-Orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap-MS and GC-Q-Orbitrap-MS). In all cases, chlorantraniliprole was fitted to a biphasic kinetic model, with R² values greater than 0.99. Dissipation was noticeably faster in greenhouse studies, in which even 96% dissipation was achieved over 53 days. One TP, IN-F6L99, was tentatively identified in both greenhouse and laboratory studies and was semiquantified by using chlorantraniliprole as the analytical standard, yielding a top value of 354 μg/kg for laboratory studies, whereas values for greenhouse studies fell under the limit of quantitation (LOQ). Finally, a total of 15 volatile coformulants were identified by GC-Q-Orbitrap-MS.

Understanding the Metabolism and Dissipation Kinetics of Flutriafol in Vegetables under Laboratory and Greenhouse Scenarios

Flutriafol is a systemic triazole fungicide that is used to control diseases in various crops. A study was developed to evaluate the metabolism and dissipation of flutriafol in two different scenarios: laboratory and greenhouse conditions. Courgette and tomato samples treated with a commercial product (IMPACT^® EVO) at the manufacturer recommended dose were analyzed, and courgette samples were also treated at double dose. Ultra-high-performance liquid chromatography coupled with Q-Orbitrap mass spectrometry (UHPLC-Q-Orbitrap-MS), performing targeted and non-targeted approaches (suspect screening and unknown analysis), were used to analyze the samples. The dissipation of flutriafol was fitted to a biphasic kinetic model, with a persistence, expressed as half-life (t_1/2), lower than 17 days. During suspect screening, three metabolites (triazole alanine, triazole lactic acid and triazole acetic acid) were tentatively identified. Unknown analysis led to the identification of four additional metabolites (C₁₆H₁₄F₂N₄, C₁₆H₁₄F₂N₄, C₁₉H₁₇F₂N₅O₂ and C₂₂H₂₃F₂N₃O₆). The results revealed that the proposed methodology is reliable for the determination of flutriafol and its metabolites in courgette and tomato, and seven metabolites could be detected at low concentration levels. The highest concentration of metabolites was found in the laboratory conditions at 34.5 µg/kg (triazole alanine). The toxicity of flutriafol metabolites was also evaluated, and some of them could be more toxic than the parent compound.