Unified Method for Target and Non-Target Monitoring of Pesticide Residues in Fruits and Fruit Juices by Gas Chromatography-High Resolution Mass Spectrometry.

A new polyvalent wide-scope analytical method, valid for both raw and processed (juices) fruits, combining target and non-target strategies, has been developed and validated to determine low concentrations of 260 pesticides, as well as many potential non-target substances and metabolites. The target approach has been validated according to SANTE Guide requirements. Trueness, precision, linearity, and robustness values were validated in raw fruit (apple) and juice (apple juice) as representative solid and liquid food commodities. Recoveries were between 70-120% and two ranges of linearity were observed: 0.5-20 µg kg-1 (0.5-20 µg L-1 apple juice) and 20-100 µg kg-1 (20-100 µg L-1 apple juice). The limits of quantification (LOQs) reached were lower than 0.2 µg kg-1 in apple (0.2 µg L-1 apple juice) in most cases. The developed method, based on QuEChERS extraction followed by gas chromatography-high resolution mass spectrometry (GC-HRMS), achieves part-per-trillions lower limits, which allowed the detection of 18 pesticides in commercial samples. The non-target approach is based on a retrospective analysis of suspect compounds, which has been optimized to detect up to 25 additional compounds, increasing the scope of the method. This made it possible to confirm the presence of two pesticide metabolites which were not considered in the target screening, phtamlimide and tetrahydrophthalimide.

Dissipation and residue determination of fluopyram and its metabolites in greenhouse crops.

BACKGROUND: Fluopyram is a pesticide widely used in tomato and cucumber crops cultivation to control fungal diseases that develop especially in environments with moderate temperatures and high humidity, such as in a greenhouse. The pathway of fluopyram dissipation has been monitored in cucumber and cherry tomato under greenhouse conditions. RESULTS: In the greenhouse trials, cherry tomato and cucumber were treated by irrigation water with the commercial product at the manufacturer's recommended dose and double dose. High-resolution mass spectrometry (HRMS) coupled to ultra-high-performance liquid chromatography (UHPLC) has been selected as the technique to obtain the identification of fluopyram and metabolites. The fate of fluopyram in greenhouse tomato and cucumber was investigated over 44 days. The metabolic pathway of fluopyram was: in a first step there was a primary transformation to fluopyram-7-hydroxy and fluopyram-8-hydroxy, isomeric compounds, and in a second phase to fluopyram-benzamide and fluopyram-pyridyl-carboxylic acid. The behavior of fluopyram does not fit any type of kinetic classical model of degradation. CONCLUSIONS: Greenhouse trials revealed that the fluopyram is a very persistent compound, and their terminal residues do not exceed maximum residue level (MRL) at the end of the study. © 2020 Society of Chemical Industry.

Optimization and establishment of QuEChERS based method for determination of propoxycarbazone and its metabolite in food commodities by liquid chromatography coupled to tandem mass spectrometry.

This study reports a method for propoxycarbazone pesticide determination including its metabolite in food commodities (lettuce, beetroot, soybean meal and honey). Both compounds were extracted, and samples cleaned using a buffered QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method based on the AOAC Official Method, followed by ultra high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). Both matrix-matched calibration curves showed good linearity (R2 = 0.99) within the tested ranges. Method performance was assessed on the basis of recovery and intra/inter-day precision studies at spiked concentrations of 10 (25) and 50 µg/kg (n = 5). Mean recovery rates were between 73 and 110%, while precision studies, assessed by relative standard deviation (RSD), were ≤20%. The limits of quantification (LOQ) were established as 10 or 25 µg/kg, depending on the matrix, which are low enough for monitoring residues at regulated maximum residue levels.

Screening of drugs and homeopathic products from Atropa belladonna seed extracts: Tropane alkaloids determination and untargeted analysis.

Homeopathic products are still a controversial issue in modern medicine, understood as complementary or alternative medicine (CAM). In this particular case, homeopathic products prepared from Atropa belladonna extracts may present specific problems due to the effects derived from its components. This article applies a simple, rapid, reliable method to the analysis of different homeopathic products obtained from Atropa belladonna; drugs containing high concentration of plant extracts; and Atropa belladonna seeds. The method was based on a simple solid-phase preconcentration method followed by ultra-high pressure liquid chromatography (UHPLC) coupled to high resolution mass spectrometry using Exactive-Orbitrap as an analyser. An in-house database was set and atropine and scopolamine were the compounds detected at highest concentrations in homeopathic products from Atropa belladonna extracts (4.57 and 2.56 µg/kg, respectively), in Belladonna ointment (4007 and 1139 µg/kg, respectively) and Belladonna seeds (338 and 32.1 mg/kg, respectively). Other tropane alkaloids such as tropine, apoatropine, aposcopolamine, tropinone, homatropine, and anisodamine were detected at lower concentrations (0.04-1.36 µg/kg). When untargeted analysis was performed, other tropane alkaloids were identified in the tested samples, such as ecgonine (0.003 µg/kg), benzoylecgonine (0.56 µg/kg), calystegines A (19.6 µg/kg), B (33.1 µg/kg), and C (1.01 µg/kg). Finally other compounds present in the homeopathic products, such as sugars (fructose, glucose, and lactose) or amino acids (valine, ornithine, leucine, and phenylalanine), were identified.

Monitoring of phytochemicals in fresh and fresh-cut vegetables: a comparison.

Bearing in mind that fresh-cut market is currently the fastest growing subsector in the food industry, a comparison of the levels of phytochemicals in fresh and fresh-cut vegetables has been carried out. Thus, several families of phytochemicals, such as phenolic acids, isoflavones, flavones, flavonols and glucosinolates were determined in fresh and fresh-cut samples including tomato, carrot, grape, eggplant and broccoli. Both type of products have potential and similar beneficial properties, regarding its content as phytochemicals, except tomato, which should be consumed as fresh. Other factors such as commercial presentation (sliced, grated, diced) and storage conditions (temperature and light) were evaluated observing that in eggplant, the content of phenolic acids is statistically different depending on the presentation. On the other hand, the content of phytochemicals was higher when fresh-cut carrots were stored at 4°C regardless of the presence or absence of light. Multivariate analysis, based on cluster analysis was used as a first approach to distinguish between fresh and fresh-cut samples, obtaining good results except for eggplant and carrot.

DNA damage in horticultural farmers: a pilot study showing an association with organophosphate pesticide exposure.

A study of horticultural farmers exposed to organophosphate pesticides (OPs) and controls investigated the relationships between OP exposure, DNA damage and oxidative stress. Blood acetylcholinesterase (AChE) and urinary dialkylphosphate (DAP) levels determined exposure and 8-hydroxy-29- deoxyguanosine (8OHdG) indicated oxidative stress status. The farmers had approximately 30% lower AChE activity and increased DAP levels compared with the controls, reflecting moderate OP exposure. They had higher DNA damage than the controls and there was a significant positive relationship between DAP and DNA damage with greater than 95% power. The farmers also had a significant positive relationship between urinary DAP and 8OHdG levels.

Determination of polychlorinated biphenyls in ambient air by gas chromatography coupled to triple quadrupole tandem mass spectrometry.

A multiresidue method for determining 22 polychlorinated biphenyls (PCBs) in air has been developed and validated by gas chromatography (GC) coupled to tandem mass spectrometry (MS/MS) using a triple quadrupole analyzer (QqQ). The method was validated in terms of both steps of sampling and analysis. The sampling method, which is based on active sampling using polyurethane foam (PUF) as adsorbent, was validated by generating standard atmospheres. The retention capacity of this sampling sorbent allows up to 5 m3 of air to be sampled without any breakthrough for most compounds. Two solvent extraction methods were compared: sonication and Soxhlet extraction with a mixture of n-hexane:diethyl ether (95:5 v/v). Both extraction methods yielded similar results, but the first one required less solvent and time. The method exhibited good accuracy (80.3-99.8%), precision (2.2-15.2%) and lower limits that allowed quantification and confirmation at levels as low as 0.008 ng/m3. Finally, the method was applied to the analysis of PCBs in the air in areas near to a municipal solid-waste landfill and directly above the refuse in the landfill, where it indicated the presence of some of the target compounds.

Assessment of relevant factors and relationships concerning human dermal exposure to pesticides in greenhouse applications.

Principal component analysis (PCA) was applied to the gas chromatographic data obtained from 23 different greenhouse trials. This was used to establish which factors, including application technique (very small, small, medium and large drop-size), crop characteristics (short/tall, thin/dense) and pattern application of the operator (walking towards or away from the treated area) are relevant to the dermal exposure levels of greenhouse applicators. The results showed that the highest exposure by pesticides during field applications in greenhouses, in the climatic conditions and in the crop conditions typical of a southern European country, occurs on the lower legs and front thighs of the applicators. Similar results were obtained by hierarchical cluster analysis (HCA). Drop-size seems to be very important in determining total exposure, while height and density of crops have little influence on total exposure under the conditions of the present study. No pesticide type is a major factor in total exposure. The application of multiple regression analysis (MRA) allowed assessment of the relationships between the pesticide exposure of the less affected parts of the body with the most affected parts.

Quality control criteria for analysis of organic traces in water.

The aim of this paper is the discussion of quality control (QC) criteria for environmental monitoring of organic contaminants at trace levels in water. In addition, QC criteria in the identification and confirmation of target analytes have been considered.