Study on the enantioselective behaviors, activity, toxicity and mechanism of novel SDHI fungicide benzovindiflupyr to reduce the environmental risks.

Benzovindiflupyr (BEN) has emerged as one of the fastest-growing SDHI fungicides in recent years, but it is considered "very highly toxic" to aquatic fish, invertebrates and crustaceans (EC50 or LC50, 0.0035-0.056 mg/L, acute toxicity). The comprehensive study on bioactivity, toxicity, and degradation behaviors of BEN at the enantiomeric level would facilitate the development of a high-efficiency and low-risk application method. The bioactivities of 1S, 4R-(-)-BEN against five target pathogens (Alternaria alternata, Phoma multirostrata, Selerotium rolfsii, Magnaporthe oryzae, and Rhizoctonia solani) (EC50, 0.00562-0.329 mg/L, high-efficiency) were 6.7-1029 times higher than 1R, 4S-(+)-BEN, demonstrating significant enantioselectivity. For Danio rerio, 1S, 4R-(-)-BEN (LC50, 0.0360 mg/L, "very highly toxic") exhibited higher toxicity than 1 R, 4S-(+)-BEN, but the toxic interaction was concentration addition (TUrac, 0.94), indicating an enhanced toxicity in the presence of 1R, 4S-(+)-BEN. Molecular docking was employed to offer insights at the molecular level and elucidate the factors influencing enantioselectivity. The stronger binding affinity of 1S, 4R-(-)-BEN with SDH was in line with the quantitative experimental findings. The degradation of two BEN enantiomers in four different fruits followed the first-order degradation kinetics equation, and displayed enantioselectivity. The preferential degradation of 1R, 4S-(+)-BEN was found in pears and grapes, while varying enantioselectivity was found at different stages in tomatoes and watermelons. The residual concentrations of BEN in grapes were higher than the EU's MRL, which in the other three fruits were below the MRLs during the sampling. In conclusion, 1S, 4R-(-)-BEN proved to be the more effective monomer. Utilizing the pure monomer could not only reduce the dosage of racemate by about 44-59 %, but also mitigate the risk of introducing inefficient monomer into the environment (especially for fish).

Transfer and risk assessment of fipronil in laying hen tissues and eggs.

Fipronil is a persistent insecticide known to transfer into hen eggs from exposure from animal drinking water and feed, but some questions remain regarding its transfer behavior and distribution characteristics. Therefore, the dynamic metabolism, residue distribution and transfer factor (TF) of fipronil were investigated in 11 edible tissues of laying hens and eggs over 21 days. After a continuous low-dose drinking water exposure scenario, the sum of fipronil and all its metabolites (defined as fipronilT) quickly transferred to each edible tissue and gradually increased with exposure time. FipronilT residue in eggs first appeared at 3 days and then gradually increased. After a single high-dose feed exposure scenario, fipronilT residue in edible tissues first appeared after 2 h, quickly peaked at 1 day, and then gradually decreased. In eggs, fipronilT residue first appeared at 2 days, peaked 6-7 days and then gradually decreased. The TF values followed the order of the skin (0.30-0.73) > egg yolk (0.30-0.71) > bottom (0.21-0.59) after drinking water exposure, and the order of the skin (1.01-1.59) > bottom (0.75-1.1) > egg yolk (0.58-1.10) for feed exposure. Fipronil sulfone, a more toxic compound, was the predominant metabolite with higher levels distributed in the skin and bottom for both exposure pathways. FipronilT was distributed in egg yolks rather than in albumen owing to its lipophilicity, and the ratio of egg yolk to albumen may potentially reflect the time of exposure. The distinction is that the residues after feed exposure were much higher than that after drinking water exposure in edible tissues and eggs. The study highlights the residual characteristics of two exposure pathways, which would contribute to the tracing of contamination sources and risk assessment.

6PPD induced cardiac dysfunction in zebrafish associated with mitochondrial damage and inhibition of autophagy processes.

The compound 6PPD is widely acknowledged for its antioxidative properties; however, concerns regarding its impact on aquatic organisms have spurred comprehensive investigations. In our study, we advanced our comprehension by revealing that exposure to 6PPD could induce cardiac dysfunction, myocardial injury and DNA damage in adult zebrafish. Furthermore, our exploration unveiled that the exposure of cardiomyocytes to 6PPD resulted in apoptosis and mitochondrial injury, as corroborated by analyses using transmission electron microscopy and flow cytometry. Significantly, our study demonstrated the activation of the autophagy pathway in both the heart of zebrafish and cardiomyocytes, as substantiated by transmission electron microscopy and immunofluorescent techniques. Importantly, the increased the expression of P62 in the heart and cardiomyocytes suggested an inhibition of the autophagic process. The reduction in autophagy flux was also verified through in vivo experiments involving the infection of mCherry-GFP-LC3. We further identified that the fusion of autophagosomes and lysosomes was impaired in the 6PPD treatment group. In summary, our findings indicated that the impaired fusion of autophagosomes and lysosomes hampered the autophagic degradation process, leading to apoptosis and ultimately resulting in cardiac dysfunction and myocardial injury. This study discovered the crucial role of the autophagy pathway in regulating 6PPD-induced cardiotoxicity. SYNOPSIS: 6PPD exposure inhibited the autophagic degradation process and induced mitochondrial injury and apoptosis in the heart of adult zebrafish.

Toxic mechanisms of imazalil, azoxystrobin and their mixture to hook snout carp (Opsariichthys bidens).

While combinations of pesticides better represent actual conditions within aquatic ecosystems, the specific toxic effects of these combinations have not been determined yet. The objective of this research was to assess the combined impact of imazalil and azoxystrobin on the hook snout carp (Opsariichthys bidens) and delve into the underlying causes. Our findings indicated that the 4-day LC50 value for imazalil (1.85 mg L-1) was greater than that for azoxystrobin (0.90 mg L-1). When imazalil and azoxystrobin were combined, they presented a heightened effect on the species. Enzyme activities like SOD, CAT, GST, and CarE, along with androgen and estrogen levels, displayed marked differences in most single and combined treatments in comparison to the baseline group. Moreover, four genes (mn-sod, cu-sod, il-1, and esr) related to oxidative stress, immunity, and the endocrine system exhibited more pronounced expression changes when exposed to combined pesticides rather than individual ones. Our tests revealed that the combined use of imazalil and azoxystrobin had more detrimental effect on aquatic vertebrates than when evaluated individually. This finding suggested that future ecological hazard analyses based only on individual tests might not sufficiently safeguard our aquatic ecosystems.

Review of fruits flavor deterioration in postharvest storage: Odorants, formation mechanism and quality control.

Fruits flavor deterioration is extremely likely to occur during post-harvest storage, which not only damages quality but also seriously affects its market value. This work focuses on the study of fruits deterioration odorants during storage by describing their chemical compositions (i.e., alcohols, aldehydes, acids, and sulfur-containing compounds). Besides, the specific flavor deterioration mechanisms (i.e., fermentation metabolism, lipid oxidation, and amino acid degradation) inducing by factors (temperature, oxygen, microorganisms, ethylene) are summarized. Moreover, quality control strategies to mitigate fruits flavor deterioration by physical (temperature control, hypobaric treatment, UV-C, CA) and chemical (1-MCP, MT, NO, MeJA) techniques are also proposed. This review will provide useful references for fruits flavor control technologies development.

Potential effects of individual and combined exposure to tetraconazole and cadmium on zebrafish from the perspective of enantioselectivity and intestinal microbiota.

As the wide use of pesticides, they could form combined pollution with heavy metals, which would affect their environmental behaviors and toxic effects. Particularly, the effects would be more intricate for chiral pesticides. In this study, the accumulation and dissipation trends of tetraconazole enantiomers in zebrafish were investigated by individual and combined exposure of cadmium (Cd) and tetraconazole (including racemate and enantiomers) after confirming the absolute configuration of tetraconazole enantiomer. For the enantiomer treatments, Cd enhanced the accumulation of S-(+)-tetraconazole, but declined the concentrations of R-(-)-tetraconazole in zebrafish. The dissipation half-lives of tetraconazole enantiomers were extended by 1.65-1.44 times after the combined exposure of Cd and enantiomers. The community richness and diversity of intestinal microbiota were reduced in all treatments, and there were significant differences in R + Cd treatment. There was synergistic effect between Cd and S-(+)-tetraconazole for the effects on the relative abundances of Fusobacteria, Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes. For R-(-)-tetraconazole, Cd mainly exhibited antagonistic effects. In the combined exposure of Cd and S-(+)-tetraconazole, the relative abundance changes of Cetobacterium (Fusobacteria, increase) and Edwardsiella (Proteobacteria, decrease) might affect the carbohydrate metabolism and energy metabolism, and led to the increase of S-(+)-tetraconazole bioaccumulation concentration. In the combined exposure of Cd and R-(-)-tetraconazole, Cd could increase the relative abundance of Edwardsiella (Proteobacteria), and affect the amino acid metabolism, which might reduce the bioaccumulation concentration of R-(-)-tetraconazole. This study reported for the first time that the abundance of intestinal microbiota in zebrafish might affect the bioaccumulation and dissipation of tetraconazole enantiomers, and would provide new insight for the study of combined pollutions.

Development and comprehensive SBSE-GC/Q-TOF-MS analysis optimization, comparison, and evaluation of different mulberry varieties volatile flavor.

Optimization of seven parameters of stir bar sorptive extraction (SBSE) on mulberry volatile components for the first time. A total of 347 volatile components were identified and quantified in 14 mulberry varieties, predominantly encompassing esters, aldehydes, terpenoids, hydrocarbons, ketones, alcohols, heterocyclics, acids, and phenols. Hexanal and (E)-2-hexenal were the dominant volatiles. Furthermore, 79 volatile compounds characterized by odor activity values (OAVs) > 1 were identified, making a significant contribution to the distinctive mulberry flavor. "Green" notes were the most intense, followed by "fatty" and "fruity". Utilizing odor ring charts, the volatile flavor characteristics of the 14 mulberry varieties could be intuitively distinguished. This study not only established a viable methodology for differentiating mulberry varieties but also laid a theoretical foundation for the quality evaluation and variety breeding of mulberry flavor.

Enzymatic and transcriptional level changes induced by the co-presence of lead and procymidone in hook snout carp (Opsariichthys bidens).

Understanding the interactions between different environmental pollutants is necessary in ecotoxicology since environmental contaminants never appear as single components but rather in combination with other substances. Heavy metals and pesticides are commonly detected in the environment, but the characterization of their mixture toxicity has been inadequately explored. This research aimed to elucidate the mixture impacts of the heavy metal lead (Pb) and the pesticide procymidone (PCM) on the hook snout carp (Opsariichthys bidens) using an array of biomarkers. The data showed that Pb and PCM possessed almost equivalent acute toxicity to the animals, with 4-days LC50 values of 120.9 and 85.15 mg L-1, respectively. Combinations of Pb and PCM generated acute synergistic effects on O. bidens. The contents of malondialdehyde (MDA), antioxidative (SOD), apoptotic (caspase-9), and detoxifying enzymes glutathione S-transferase (GST) and cytochrome P450 (CYP450) significantly changed after most of the mixture exposures compared with the baseline level and the corresponding individual exposures. This suggests the induction of oxidative stress, cell damage, and detoxification dysfunction. The expressions of eight genes (mn-sod, cu-sod, p53, cas3, erß1, esr, ap, and klf2α) associated with oxidative stress, cell apoptosis, immune response, and hormonal functions exhibited pronounced changes when challenged with the mixture compared to the individual treatments. This indicates the occurrence of immune dysregulation and endocrine disorder. These findings provide an overall understanding of fish upon the challenge of sublethal toxicity between Pb and PCM and can be adopted to evaluate the complicated toxic mechanisms in aquatic vertebrates when exposed to heavy metal and pesticide mixtures. Additionally, these results might guide environmental regulation tactics to protect the population of aquatic vertebrates in natural ecosystems.

Enantioselective fate and risk assessment of chiral fungicide pydiflumetofen in rice-fish and wheat farming systems.

Fungicides have been widely used for reducing the losses caused by plant diseases. Rice and wheat are the most basic food crops, and the potential risks after applying fungicides are worthy of attention. Especially rice-fish farming system is an ecological symbiosis system that is beneficial to both environmental and ecological protection. However, the application of pesticides will stress the ecosystem, and the pesticide residues in rice and fish would be transmitted along the food chain, which is harmful to human health. Here, the enantioselective behaviors of chiral pydiflumetofen in rice-fish and wheat farming systems were clarified. In the rice-fish farming system, pydiflumetofen enantiomers were preferentially attached to the plants, entering the paddy water and settling into the paddy soil, and then accumulating and dissipating in the fish. With the growth of rice, it was transported to rice fruits. The wheat farming system was similar. Enantioselective dissipation occurred in carp (Cyprinus carpio), brown rice and wheat soil, and S-(+)-pydiflumetofen was preferentially dissipated. In other words, R-(-)-pydiflumetofen showed higher concentrations, especially in carp, which meant R-(-)-pydiflumetofen was more easily accumulated in the environment, and posed a greater potential risk to the farming system. The pydiflumetofen residues in brown rice and wheat were lower than MRLs from the EFSA (0.02 mg/kg) and eCFR (0.3 mg/kg), respectively. What deserves attention is that the MRL of pydiflumetofen in fish is not clear. Meanwhile, pydiflumetofen in paddy soil and wheat soil had a persistent residual effect, and the risks could not be ignored. Combined with the previous research, developing S-(+)-pydiflumetofen products will help to reduce the dosage and reduce the risks to environment and people. This study evaluated the environmental fate and risk of chiral pydiflumetofen from the perspective of farming system, and would provide data support for its rational use and risk assessment.

Integrated QuEChERS combined with LC-MS/MS for high-throughput analysis of per- and polyfluoroalkyl substances in milk.

In this study, an integrated QuEChERS method was developed for the rapid determination of 22 per- and polyfluoroalkyl substances (PFASs) in milk by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The extraction and purification processes were combined into one step with this method. Meanwhile, the solid-liquid separation was carried out by magnetic suction (Fe3O4-SiO2) instead of the centrifugal process. The primary experimental parameters were optimized, including the type of extraction solvent, the amounts of magnetic nanomaterials (Fe3O4-SiO2), and the purification materials (ZrO2 and C18). The developed method exhibits high precision (RSDs < 9.9%), low limits of detection (0.004-0.079 µg/kg) and limits of quantitation (0.01-0.26 µg/kg), and acceptable recovery (71.7-116%) under optimized conditions. The developed integrated QuEChERS method had clear superiority in terms of sample pretreatment time, operating procedures, reagent amount, and recovery. This makes it an excellent alternative analytical technique for PFAS residue measurement at low micrograms-per-kilogram ranges with desirable sensitivity.

Stereoselective study on chiral fungicide metconazole in four kinds of fruits: Absolute configuration, SFC-MS/MS enantioseparation, degradation and risk assessment.

Metconazole is a novel chiral fungicide with two chiral carbon atoms, but the research on its stereoselective behavior is limited. Therefore, the stereoselective behaviors of metconazole in four fruits, including grape, peach, pear and jujube, were summarized in this study. After determining the absolute configuration of metconazole stereoisomers, a chiral separation method through supercritical fluid chromatography/tandem triple quadrupole mass spectrometry was first developed, which combined an improved QuEChERS method obtained the recoveries of 71.6-113 % with RSD ≤ 19.8 %. The LOD and LOQ were 4.30-95.9 and 10.5-143.2 ng/kg, respectively. Different stereoselective and diastereoselective behaviors were observed in four fruits. Dietary risk assessments of rac-metconazole were performed in populations with different ages and genders. Both acute (RQa, 0.0124-0.140 %) and chronic (HQ, 0.0234-0.0794 %) intake risks were acceptable. The results of this study would contribute to more complete risk assessments of metconazole and provide data for chiral studies.

Combined toxicity of aflatoxin B1 and tebuconazole to the embryo development of zebrafish (Danio rerio).

Mycotoxins and pesticides are pervasive elements within the natural ecosystem. Furthermore, many environmental samples frequently exhibit simultaneous contamination by multiple mycotoxins and pesticides. Nevertheless, a significant portion of previous investigations has solely reported the occurrence and toxicological effects of individual chemicals. Global regulations have yet to consider the collective impacts of mycotoxins and pesticides. In our present study, we undertook a comprehensive analysis of multi-level endpoints to elucidate the combined toxicity of aflatoxin B1 (AFB1) and tebuconazole (TCZ) on zebrafish (Danio rerio). Our findings indicated that AFB1 (with a 10-day LC50 value of 0.018 mg L-1) exhibits higher toxicity compared to TCZ (with a 10-day LC50 value of 2.1 mg L-1) toward D. rerio. The co-exposure of AFB1 and TCZ elicited synergistic acute responses in zebrafish. The levels of GST, CYP450, SOD, and Casp-9 exhibited significant variations upon exposure to AFB1, TCZ, and their combined mixture, in contrast to the control group. Additionally, eight genes, namely cat, cxcl-cic, il-1ß, bax, apaf-1, trß, ugtlab, and vtg1, displayed marked alterations when exposed to the chemical mixture as opposed to individual substances. Therefore, further exploration of the underlying mechanisms governing joint toxicity is imperative to establish a scientific basis for evaluating the risk associated with the combined effects of AFB1 and TCZ. Moreover, it is essential to thoroughly elucidate the organ system toxicity triggered by the co-occurrence of mycotoxins and pesticides.

Stereoselective, Diastereoselective Dissipation and Risk Assessment of Chiral Metconazole in Soybean, Peanut, Cabbage, Celery, Tomato, and Soil.

The stereoselective behaviors and dietary risks of metconazole (MZE) in soil and five vegetables were investigated. The results showed that there was species-specific stereoselective and diastereoselective dissipation, and the half-lives ranged from 0.69 to 8.17 days. cis-(+)-1S,5R-MZE was preferentially dissipated in soybean pods, cabbages, celeries, and tomatoes, which was contrary to soybean plants and soil. trans-(+)-1R,5R-MZE was preferentially dissipated in peanut plants, peanut shells, celeries, and tomatoes, while trans-(-)-1S,5S-MZE was preferentially dissipated in soybean plants. cis-MZE was preferentially dissipated in the test vegetables and soil, except celery. The stereoisomeric excess changes were higher than 10%, indicating that the stereoselectivity and diastereoselectivity should be considered in the risk assessment of MZE in soybean plants, pods, and peanut plants. The acute and chronic dietary intake risks of rac-MZE for different groups of people were acceptable. The preferentially dissipated and high activity cis-(+)-1S,5R-MZE with lower toxicity might be suitable for application as monocase.

Fabrication of poly-dopamine-modified magnetic nanomaterial and development of integrated QuEChERS method for 122 pesticides residue analysis in fruits.

A rapid and accurate integrated QuEChERS method was established for the determination of multi-pesticide residues in fruits. Poly-dopamine-modified magnetic nanomaterial (Fe3O4-pDA) was homemade and characterized. The prepared Fe3O4-pDA has the functional group of absorbing the saccharides, and can be used as co-adsorbent with 3-(N, n­diethyl amino) propyl trimethoxy-silane (PSA) in the developed integrated QuEChERS method to purify the fruit matrix, thus achieve the accurate determination of multi-pesticides residue. Grape was used as the representative sample to explore the influence of the salting out agent and each purification adsorbent on the pesticide recoveries. Under the optimized conditions, the proposed method showed good linearity for 92.6% of pesticides in the concentration range of 1-150 µg L-1 with method limit of quantitative (mLOQs) ranged from 10 to 18 µg kg-1. Spiked recoveries experiments were performed on four kinds of grapes and other fruits (apple, watermelon, pear, jujube and peach), in which satisfactory recoveries and precision were obtained for most of the pesticides. Meanwhile, comparison experiments also verified this method was superior to the traditional QuEChERS method in terms of convenient operation, high efficiency and low reagent consumption. The further real sample analysis was performed using this method, and the overall detection rate was 52%, while 2% of samples were exceeding the maximum residue limits. All results confirmed that the proposed method could be used for the rapid, simple, low-costing and effective analyses of trace multi-pesticides residue in fruit samples.

Development of S-penthiopyrad for bioactivity improvement and risk reduction from the systemic evaluation at the enantiomeric level.

For the purpose of screening high-efficiency and low-risk green pesticides, a systematic study on fungicide penthiopyrad was conducted at the enantiomeric level. The bioactivity of S-(+)-penthiopyrad (median effective concentration (EC50), 0.035 mg/L) against Rhizoctonia solani was 988 times higher than R-(-)-penthiopyrad (EC50, 34.6 mg/L), which would reduce 75% usage of rac-penthiopyrad under the same efficacy. Furthermore, their antagonistic interaction (toxic unit (TUrac), 2.07) indicated the existence of R-(-)-penthiopyrad would reduce the fungicidal activity of S-(+)-penthiopyrad. AlphaFold2 modeling and molecular docking illustrated that S-(+)-penthiopyrad had the higher binding ability with the target protein than R-(-)-penthiopyrad, showing higher bioactivity. For model organism Danio rerio, S-(+)-penthiopyrad (median lethal concentrations (LC50), 3.02 mg/L) and R-(-)-penthiopyrad (LC50, 4.89 mg/L) were both less toxic than rac-penthiopyrad (LC50, 2.73 mg/L), and the existence of R-(-)-penthiopyrad could synergistically enhance the toxicity of S-(+)-penthiopyrad (TUrac, 0.73), using S-(+)-penthiopyrad would reduce at least 23% toxicity to fish. The enantioselective dissipation and residues of rac-penthiopyrad were tested in three kinds of fruits, and their dissipation half-lives ranged from 1.91 to 23.7 d. S-(+)-penthiopyrad was dissipated preferentially in grapes, which was R-(-)-penthiopyrad in pears. On the 60th d, the residue concentrations of rac-penthiopyrad in grapes were still higher than its maximum residue limit (MRL), but the initial concentrations were lower than their MRL values in watermelons and pears. Thus, more tests in different cultivars of grapes and planting environments should be encouraged. Based on the acute and chronic dietary intake risk assessments, the risks in the three fruits were all acceptable. In conclusion, S-(+)-penthiopyrad is a high-efficiency and low-risk alternative to rac-penthiopyrad.

Enantioselective Behaviors of Chiral Fungicide Penthiopyrad in Five Kinds of Crops and Whole-Age Dietary Risk Assessments.

Penthiopyrad is a widely used succinic dehydrogenase inhibitor fungicide with two enantiomers, while the data on its enantioselective behaviors in crops are limited. The enantioselective dissipation may directly or indirectly expose people to the preferentially residual enantiomer, which may affect the dietary risks of chiral penthiopyrad. In this study, the enantioselective behaviors of chiral penthiopyrad in five kinds of crops and whole-age dietary risk assessments were conducted. The dissipation half-lives of penthiopyrad enantiomers were in the range of 0.48-13.7 days. S-(+)-Penthiopyrad was preferentially dissipated in soybean plants, soybean, peanut kernel, peanut shell, celery, tomato, and soil, which was opposite in cabbage. The opposite enantioselective residue might expose people to different enantiomer, which bring more complex risks. On the 35th day (the harvest time), the residue concentrations of penthiopyrad were all lower than MRLs except celery. For acute dietary intake risks, the children aged 2-7 suffered the highest risks, especially for cabbage (RQa, 138%) and celery (RQa, 140%), which were unacceptable. For other people, the acute dietary intake risks of rac-penthiopyrad in cabbage and celery were also very high and in the range of 88.6-94.8%, which should raise concern. The chronic dietary intake risks of rac-penthiopyrad in the all crops for groups of Chinese population with different ages and genders were acceptable (HQ, 0.0006-29.1%), and the risks were the highest in celery, especially for children aged 2-7. This study could provide data support for the environmental behaviors and risk assessments of penthiopyrad at the enantiomeric level.

Fabrication of magnetic magnesium oxide cleanup adsorbent for high-throughput pesticides residue analysis coupled with supercritical fluid chromatography-tandem mass spectrometry.

A rapid and accurate analytical method was established for multiple pesticide residues in complex matrices based on magnetic dispersive solid phase extraction (d-SPE) and supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS). To develop an efficient magnetic d-SPE method, magnetic adsorbent modified with magnesium oxide (Fe3O4-MgO) was prepared via layer-by-layer modification and used as cleanup adsorbent for removal of interferences that contain a large number of hydroxyl or carboxyl groups in the complex matrix. The obtained Fe3O4-MgO coupled with 3-(N,N-Diethylamino)-propyltrimethoxysilane (PSA) and octadecyl (C18) were used as d-SPE purification adsorbents and their dosages were systematically optimized with Paeoniae radix alba as the matrix model. Combined with SFC-MS/MS, rapid and accurate determination of 126 pesticide residues in the complex matrix was achieved. Further systematic method validation showed good linearity, satisfactory recovery, and wide applicability. The average recoveries of the pesticides at 20, 50, 80, and 200 µg kg-1 were 110, 105, 108, and 109%, respectively. The proposed method was applied to complex medicinal and edible root plants, such as Puerariae lobate radix, Platycodonis radix, Polygonati odorati rhizoma, Glycyrrhizae radix, and Codonopsis radix. The average recoveries of the pesticides at 80 µg kg-1 in these matrices were 106, 106, 105, 103, and 105%, respectively with an average relative standard deviation range of 8.24-10.2%. The results demonstrated the feasibility and wide matrix applicability of the proposed method, which is promising for pesticide residue analysis in complex samples.

[QuEChERS-liquid chromatography-tandem mass spectrometry for determination of 22 triazole pesticide residues in Chinese herbal medicines].

Eight well-known herbals in Zhejiang Province, Zhebawei, are commonly used as traditional Chinese herbal medicines owing to their rich active ingredients. However, the unavoidable use of pesticides during agricultural production has led to pesticide residue problems in these herbs. In this study, a simple, rapid, and accurate method was established to determine 22 triazole pesticide residues in Zhebawei. An improved QuEChERS method was used for sample pretreatment, and Rhizoma Atractylodis Macrocephalae was used as a representative sample. The sample was extracted with acetonitrile to eliminate some polar and nonpolar compounds, pigments, and other impurities, and the purification effects of multiwalled carbon nanotubes (MWCNTs), amino-modified multiwalled carbon nanotubes (MWCNTs-NH2), carboxylated multiwalled carbon nanotubes (MWCNTs-COOH), crosslinked polyvinylpyrrolidone (PVPP), zirconium dioxide (ZrO2), 3-(N,N-diethylamino)-propyltrimethoxysilane (PSA), octadecyl (C18), and graphitized carbon black (GCB) were compared. MWCNTs-COOH and C18 were selected as the purification adsorbents, and their dosages were systematically optimized. The combination of 10 mg of MWCNTs-COOH and 20 mg of C18 was eventually selected as the purification adsorbents. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used for analysis, and box graphs were plotted to present the dispersion of each group of recoveries, thus enabling the identification of the data outliers, dispersion distribution, and data symmetry. The established method was systematically verified and showed good linearity over the concentration range of 1-200 µg/L (except for bromuconazole, epoxiconazole, and etaconazole) with correlation coefficients >0.99. The average recoveries of the 22 pesticides at spiked levels of 10, 20, 100, and 200 µg/kg were in the range of 77.0%-115% with relative standard deviations (RSDs) <9.4%. The limits of detection and quantification were 1-2.5 µg/kg and 10-20 µg/kg, respectively. The applicability of the developed method to other herbals was investigated at 100 µg/kg, and the average recoveries of the target pesticides in different matrices ranged from 76.4% to 123% with RSDs <12.2%. Finally, the method established was used to detect triazole pesticide residues in 30 actual Zhebawei samples. The results showed that triazole pesticides were present in Bulbus Fritillariae Thunbergii and Dendranthema Morifolium. Difenoconazole was detected in Bulbus Fritillariae Thunbergii at contents ranging from 41.4 µg/kg to 110 µg/kg, while difenoconazole, myclobutanil, triadimenol and propiconazole were detected in Dendranthema Morifolium at contents ranging from 16.1 µg/kg to 250 µg/kg. The established method can meet the requirements for the accurate quantitative analysis of triazole fungicides in Zhebawei.

Characterization of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD)-induced cardiotoxicity in larval zebrafish (Danio rerio).

N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) is a type of p-phenylenediamine (PPD), which is widely used in the manufacture of rubber tires owing to its excellent antiozonant properties. In this study, the developmental cardiotoxicity of 6PPD was evaluated in zebrafish larvae, and the LC50 was approximately 737 µg/L for the larvae at 96 h post fertilization (hpf). In the 6PPD treatment of 100 µg/L, the accumulation concentrations of 6PPD were up to 2658 ng/g in zebrafish larvae, and 6PPD induced significant oxidative stress and cell apoptosis in the early developmental stages of zebrafish. Transcriptome analysis showed that 6PPD exposure could potentially cause cardiotoxicity in larval zebrafish by affecting the transcription of the genes related to the calcium signal pathway and cardiac muscle contraction. The genes related to calcium signaling pathway (slc8a2b, cacna1ab, cacna1da, and pln) were verified by qRT-PCR, which were significantly downregulated in larval zebrafish after exposing to 100 µg/L of 6PPD. Simultaneously, the mRNA levels of the genes related to cardiac functions (myl7, sox9, bmp10, and myh71) also respond accordingly. H&E staining and heart morphology investigation indicated that cardiac malformation occurred in zebrafish larvae exposed to 100 µg/L of 6PPD. Furthermore, the phenotypic observation of transgenic Tg (myl7: EGFP) zebrafish also confirmed that 100 µg/L of 6PPD exposure could change the distance of atria and ventricles of the heart and inhibit some key genes (cacnb3a, ATP2a1l, ryr1b) related to cardiac function in larval zebrafish. These results revealed the toxic effects of 6PPD on the cardiac system of zebrafish larvae.

Green synthesis of Fe3O4@SiO2@Salg particles for organophosphorus pesticides removal: Mechanisms, biosafety, and application.

A biosafe magnetic Fe3O4@SiO2@Salg (GMS) was successfully developed via a simple and economic method. Fe3O4@SiO2 particles were selected as the magnetic core, and they directly interacted with sodium alginate, thus mitigating the use of cross-linking agents. The microstructure, properties, and formation mechanism of GMS were examined using FE-SEM, TEM, VSM, TGA, zeta potential, and FT-IR. The as-developed GMS was used as a desirable adsorbent to remove organophosphorus pesticides (OPPs) from water bodies, and the influence of different factors on the removal efficiencies of OPPs was investigated. Optimal preparation conditions were determined, and the excellent removal efficiencies of the 18 OPPs were achieved in this study (80.5%-100% for tap, river, and seawater). After the GMS was recycled eight times, the removal efficiencies of 18 OPPs were maintained at >80%. Adsorption kinetics and isotherm models showed that the adsorption process was accurately fitted with the Langmuir isotherm and pseudo-second-order models. The values of ΔG, ΔH, and ΔS were negative, indicating that the OPPs were adsorbed on the GMS spontaneously via an exothermal reaction, and chemisorption was the dominant adsorption mechanism. Overall, the as-developed GMS was biosafe as revealed by cytotoxicity experiments. GMS had good environmental security, stability, and reusability, and it exhibited excellent potential for removing OPPs from aqueous solutions without causing secondary pollution.