picoxystrobin and pyrachlostrobin

In this study, a simple, efficient, and green effervescence tablet-assisted microextraction method based on the solidification of deep eutectic solvent (ETA-ME-SDES) was developed to determine picoxystrobin, pyraclostrobin, and trifloxystrobin in water, juice, wine, and vinegar samples by HPLC. An eco-friendly, hydrophobic, deep eutectic solvent (DES, acting as the extraction solvent) was synthesized by thymol and octanoic acid in the molar ratio of 1:5. The extraction solvent dispersed in sample solutions with the assistance of pH adjustment and effervescence reaction, and was collected after solidification in an ice bath. Several essential conditions, including the type and the volume of DESs, the amount of ammonia hydroxide, and the components of effervescence tablets were optimized. The limits of detection ranged from 0.15 to 0.38 μg L

Topics: Acetates; Acetic Acid; Chromatography, High Pressure Liquid; Fruit and Vegetable Juices; Fungicides, Industrial; Hydrogen-Ion Concentration; Imines; Limit of Detection; Liquid Phase Microextraction; Salts; Strobilurins; Water Pollutants, Chemical; Wine

Pyraclostrobin and picoxystrobin are two representative pesticides of strobilurins used to treat cucumber downy mildew, which have raised issues of food safety and human health. A new formulation containing these two compounds is being prepared for marketing in China.. The dissipation and residual levels of pyraclostrobin and picoxystrobin in cucumbers under field conditions were determined simultaneously by a validated method via liquid chromatography-tandem mass spectrometry (LC-MS/MS). The dissipation rules were described by first-order kinetics and the half-lives of pyraclostrobin and picoxystrobin were less than 8.2 days and 3.4 days. The highest terminal residue of pyraclostrobin was 0.014 mg kg. Pyraclostrobin and picoxystrobin degraded easily in cucumbers under open field conditions. The long-term and short-term risks caused by final residues of pyraclostrobin and picoxystrobin were insignificant. The recommended pre-harvest interval of 3 days was safe. The article will be helpful in rational use of these pesticides and MRL formulation of picoxystrobin on cucumber. © 2020 Society of Chemical Industry.

Topics: China; Chromatography, Liquid; Cucumis sativus; Drug Residues; Food Contamination; Fruit; Fungicides, Industrial; Half-Life; Kinetics; Risk Assessment; Strobilurins; Tandem Mass Spectrometry

Topics: Agriculture; Chromatography, Liquid; Fruit; Fungicides, Industrial; Pesticide Residues; Strobilurins; Tandem Mass Spectrometry; Vegetables

Strobilurins have been reported highly toxic to non-target aquatic organisms but few illustrated how they cause toxic effects on algae. This study investigated the acute toxicity of Kresoxim-methy (KRE), Pyraclostrobin (PYR), Trifloxystrobin (TRI) and Picoxystrobin (PIC) on two algae and their toxicity mechanisms. Four strobilurins showed lower toxic effects on Chlorella pyrenoidsa but higher on Chlorella vulgaris. bc1 complex activities in C. vulgaris were significantly inhibited by all strobilurins, suggesting bc 1 complex might be the target of strobilurin toxicity in algae. Moreover, SOD, CAT and POD activities were significantly up-regulated by all doses of KRE, PYR and PIC. In contrast, low concentrations of TRI stimulated SOD and POD activities but highest concentration significantly inhibited those activities. Comet assays showed damaged DNA in C. vulgaris by four strobulirins, suggesting their potential genotoxic threats to algae. The results illustrated acute toxicity by strobulirins on algae and their possible toxicity mechanisms.

Topics: Acetates; Algal Proteins; Catalase; Chlorella; Chlorella vulgaris; Gene Expression Regulation; Gene Expression Regulation, Enzymologic; Imines; Peroxidase; Strobilurins; Superoxide Dismutase; Water Pollutants, Chemical

Topics: Acetates; Animals; Antioxidants; Fungicides, Industrial; Imines; Oxidative Stress; Reactive Oxygen Species; Strobilurins; Zebrafish

The extreme specificity of immunoaffinity chromatography (IAC) columns coupled to the high sensitivity of ion mobility spectrometry (IMS) measurements makes this combination really useful for rapid, selective, and sensitive determination of a high variety of analytes in different samples. The capabilities of the IAC-IMS coupling have been highlighted under three different scenarios: (i) multiclass residue analysis using a single IAC column, (ii) multiclass residue analysis using stacked IAC columns, and (iii) isomer analysis. In the first case, the determination of three strobilurin fungicides - azoxystrobin, picoxystrobin, and pyraclostrobin - in water and strawberry juice was considered, obtaining limits of quantification (LOQs) from 11 to 63μgL(-1). Recoveries from 96 to 106% for water, and from 67 to 104% for strawberry juice were obtained. In the second case, anilinopyrimidine compounds, including two analytes with similar drift time, were selectively retained in different IAC columns and analyzed after independent elution in commercial wine samples by IMS. LOQ values of 16, 14 and 12μgL(-1) were obtained for pyrimethanil, mepanipyrim, and cyprodinil, respectively. The obtained recoveries for wine samples spiked with 25 and 100μgL(-1) were from 82 to 123%. Additionally, the stacked IAC columns concept was applied to the separation of Z and E isomers of azoxystrobin that were selectively retained in specific IAC columns and quantified by IMS. Recoveries between 91 and 94% were obtained for both isomers in water samples.

Topics: Acrylates; Carbamates; Chromatography, Affinity; Fragaria; Fruit and Vegetable Juices; Fungicides, Industrial; Methacrylates; Pyrazoles; Pyridines; Pyrimidines; Sensitivity and Specificity; Stereoisomerism; Strobilurins; Water; Wine

A novel method, ultrasound-assisted surfactant-enhanced emulsification microextraction with solidification of floating organic droplet (UASEME-SFOD), has been developed for the extraction of four strobilurin fungicides (kresoxim-methyl, picoxystrobin, pyraclostrobin and trifloxystrobin) in fruit juices. In the UASEME-SFOD technique, Tween 80 was used as emulsifier, and 1-undecanol was used as extraction solvent without using any organic dispersive solvent. Several parameters that affect the extraction efficiency, such as the kind and volume of extraction solvent, the type and concentration of the surfactant, extraction time, extraction temperature and salt addition were investigated and optimized. Under the optimum extraction condition, the method yields a linear calibration curve in the concentration range from 5 to 10,000 ng mL(-1) for the targeted analytes with the correlation coefficient ranging from 0.9991 to 0.9998. The enrichment factors were in the range between 95 and 135, and the limits of detection of the method were 2-4 ng mL(-1). The fruit juice samples were successfully analyzed using the proposed method, and the relative recoveries at fortified levels of 50 and 100 ng mL(-1) were in the range of 82.6-97.5%.

Topics: Acetates; Acrylates; Beverages; Carbamates; Chromatography, High Pressure Liquid; Emulsions; Fruit; Fungicides, Industrial; Imines; Limit of Detection; Methacrylates; Phenylacetates; Pyrazoles; Pyridines; Strobilurins; Surface-Active Agents; Temperature; Ultrasonics

An LC-MS/MS method was developed for the simultaneously determination of seven strobilurin fungicide residues in Chinese herbs. The strobilurin fungicides include Z-metominostrobin, kresoxim-methyl, dimoxystrobin, picoxystrobin, pyraclostrobin, azoxystrobin and trifloxystrobin. The sample was extracted with ethyl acetate and cleaned-up by an amino SPE column. The seven strobilurin fungicide residues were separated on a C18 column with gradient elution of 1.0 per thousand formic acid and methanol as mobile phases, and detected by ESI-MS in positive ion and selective reaction monitoring (SRM) mode. External standard method was used to the quantification with good linear relationships (r > or = 0. 996). The LOQs were 2 micro g/kg for dimoxystrobin, picoxystrobin and trifloxystrobin, 4 mciro g/kg for pyraclostrobin and azoxystrobin, 10 micro g/kg for Z-metominostrobin and kresoxim-methyl. The recoveries were from 60.4% to 110% with the RSDs between 1.2% and 17%. The developed method is suitable for the determination and confirmation of the seven strobilurin fungicide residues in the three of Eight Zhes ( Ophiopogon japonicus (Thunb.), Scrophularia ningpoensis Hemsl. and Corydalis yanhusuo W T Wang).

Topics: Acetates; Acrylates; Carbamates; Chromatography, Liquid; Drug Contamination; Drug Residues; Drugs, Chinese Herbal; Fungicides, Industrial; Imines; Methacrylates; Phenylacetates; Pyrazoles; Pyridines; Pyrimidines; Strobilurins; Tandem Mass Spectrometry