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The widespread use of pesticides poses significant risks to food and environmental safety. Imidacloprid is one of the most effective neuroactive neonicotinoid insecticides and is effective against a broad spectrum of piercing–sucking pests. A rapid, efficient, and high-throughput analysis method for the determination of imidacloprid was developed in four minor crops with six matrices (bamboo shoot, winter jujube, fresh and dry D. officinale, and fresh and dry Fritillaria) by solid-phase extraction and HPLC-MS/MS. The procedure showed satisfying recoveries (72~111%) and RSDs (1~13%). A total of 288 samples were tested in China (Aba and Luan). Imidacloprid residues were 100% detected in fresh and dry D. officinale and winter jujube, with concentrations ranging from 0.048 to 1.550 mg·kg−1. Imidacloprid residues were also abundant in fresh and dry Fritillaria (maximal concentration of 0.021 and 0.063 mg·kg−1, respectively), followed by bamboo shoot, which had the lowest detection rate of imidacloprid (6%). Using the risk quotient (RQ) method, the long-term (RQc) and short-term (RQa) dietary risks of imidacloprid in bamboo shoot, winter jujube, fresh and dry D. officinale, and fresh and dry Fritillaria were further monitored. Based on the imidacloprid residues in this paper, the RQc and RQa were 15.03% and 0.0008~1.7604%, respectively. The RQ values were far less than 100%, showing that Chinese consumers face little health risk as a result of imidacloprid intake.

In this study, nanoindentation tests at three different strain rates within 100 nm indentation depth were conducted on an a-plane (112¯0) ZnO single crystal to investigate the effect of strain rate on its nano-scale mechanical behavior. The load–indentation-depth curves, pop-in events, hardness and Young’s moduli of an a-plane (112¯0) ZnO single crystal at different strain rates were investigated at the nano-scale level. The results indicated that, with the indentation depth increasing, the load increased gradually at each maximum indentation depth, hma, during the loading process. A distinct pop-in event occurred on each loading curve except that corresponding to the hmax of 10 nm. The applied load at the same indentation depth increased with the increasing strain rate during the nanoindentation of the a-plane (112¯0) ZnO single crystal. The higher strain rate deferred the pop-in event to a higher load and deeper indentation depth, and made the pop-in extension width larger. The hardness showed reverse indentation size effect (ISE) before the pop-in, and exhibited normal ISE after the pop-in. Both the hardness and the Young’s modulus of the a-plane (112¯0) ZnO single crystal increased with the increasing strain rate, exhibiting the positive strain-rate sensitivity.

Metalaxyl is frequently used to protect a variety of crops from fungal diseases. This study aims to establish a method for the determination of metalaxyl in Chinese bayberry, fresh Dendrobium officinale (D. officinale), and dried D. officinale by gas chromatography-tandem mass spectrometry (GC-MS/MS) and further assess dietary risk. The samples were extracted with acetonitrile and purified by the dispersed solid phase extraction method. Chinese bayberry, fresh D. officinale, and dried D. officinale samples were collected from Hangzhou and Zhangzhou in 2021 to clarify metalaxyl residue levels. The metalaxyl was quantitated by the external standard method. In the range of 0.001–0.1 mg L−1, there was good linearity under the optimal conditions. The recoveries ranged from 83.90% to 110.47%, with relative standard deviations ranging from 0.86% to 5.81%. The detection rates in Chinese bayberry, fresh D. officinale, and dried D. officinale were 97.92%, 49.29%, and 50.71%, respectively. The dietary risk of metalaxyl residues in Chinese bayberry, fresh D. officinale, and dried D. officinale was acceptable for consumers.

A rapid, efficient, simple, and high-throughput method for the simultaneous determination of 108 pesticide residues in three traditional Chinese medicines (TCMs) was established, comprising an improved QuEChERS method in combination with HPLC-MS/MS based on mixed samples. A quantity of 10 mL of acetonitrile was used as extraction solvent, and 10 mg of amino-modified multi-walled carbon nanotubes (MWCNTs-NH2) and 150 mg of anhydrous magnesium sulfate (MgSO4) were selected as sorbents for dispersive solid phase extraction. The performance of the method was verified according to the analytical quality control standards of SANTE/11813/2017 guidelines. With good linearity (R2 > 0.9984) in the range of 2–200 μg/L for all pesticides in the selected matrices, and good accuracy, precision, and high sensitivity, the recoveries were in the range of 70–120% for more than 95% of the pesticides, with a relative standard deviation (RSD) of less than 16.82% for all. The limit of detection (LOD) and limit of quantification (LOQ) of the method were 0.01–3.87 μg/kg and 0.07–12.90 μg/kg, respectively, for Fritillaria thunbergii Miq (F. thunbergii), Chrysanthemum Morifolium Ramat (C. morifolium), and Dendrobium officinale Kimura et Migo (D. officinale). The method was successfully applied to 60 batches of actual samples from different regions.

The massive use of pesticides has brought great risks to food and environmental safety. It is necessary to develop reliable analytical methods and evaluate risks through monitoring studies. Here, a method was used for the simultaneous determination of flupyradifurone (FPF) and its two metabolites in fresh ginseng, dried ginseng, ginseng plants, and soil. The method exhibited good accuracy (recoveries of 72.8–97.5%) and precision (relative standard deviations of 1.1–8.5%). The field experiments demonstrated that FPF had half-lives of 4.5–7.9 d and 10.0–16.9 d in ginseng plants and soil, respectively. The concentrations of total terminal residues in soil, ginseng plants, dried ginseng, and ginseng were less than 0.516, 2.623, 2.363, and 0.641 mg/kg, respectively. Based on these results, the soil environmental risk assessment shows that the environmental risk of FPF to soil organisms is acceptable. The processing factors for FPF residues in ginseng were 3.82–4.59, indicating that the concentration of residues increased in ginseng after drying. A dietary risk assessment showed that the risk of FPF residues from long-term and short-term dietary exposures to global consumers were 0.1–0.4% and 12.07–13.16%, respectively, indicating that the application of FPF to ginseng at the recommended dose does not pose a significant risk to consumers.

Pesticides are one of the abiotic stresses that have had an impact on the quality of agricultural products, especially in China. This study was the first to explore the soluble protein (SP) accumulation, peroxidase (POD) activity, and superoxide dismutase (SOD) activity variations in the stem and leaf of celery plants in the field after 2 h, 1, 3, 5, 8, 10, 14, 21, 28-day of spraying imidacloprid (IMI) and fenpyroximate (FEN) at various doses. The findings demonstrated that there was no notable difference in ultimate residues between 1 F and 10 F, and even with the 10 F treatment, the residues were not a concern. The SP accumulation alterations were mainly provoked by residues, which dramatically boosted in stem and eventually declined in leaf. The POD activity in celery was a dynamic process with a marked shift (enhanced and declined) when compared with non-pesticide treatment after 28 days. The field trial exhibited that the SOD was principally positioned in leaf whether pesticides were applied or not, which might be due to the distinctive structure of the celery leaf compared with the stem. No obvious linear relation between application dose and SOD activity was observed.