Magnetic Persimmon Leaf Composite: Preparation and Application in Magnetic Solid-Phase Extraction of Pesticides in Water Samples.

In recent years, the utilization of biomass materials for the removal and detection of water pollutants has garnered considerable attention. This study introduces, for the first time, the preparation of Fe3O4/persimmon leaf magnetic biomass composites. The magnetic composites were employed in a magnetic solid-phase extraction method, coupled with gas chromatography-electron capture detection (GC-ECD), for the analysis of four pesticides (trifluralin, triadimefon, permethrin, and fenvalerate) in environmental water samples. The innovative magnetic persimmon leaf composites were synthesized by in situ generation of Fe3O4 nanoparticles through coprecipitation and loaded onto persimmon leaves. These composites exhibit superparamagnetism with a saturation magnetization of 12.8 emu g-1, facilitating rapid phase separation using a magnetic field and reducing the extraction time to 10 min. Desorption can be achieved within 30 s by aspirating 20 times, eliminating the need for time-consuming and labor-intensive experimental steps like filtration and centrifugation. The specific surface area of the magnetic composite adsorbent increased from 1.3279 m2 g-1 for the original persimmon leaf to 5.4688 m2 g-1. The abundant hydroxyl and carboxyl groups on the composites provide ample adsorption sites, resulting in adsorption capacities ranging from 55.056 mg g-1 to 73.095 mg g-1 for the studied pesticides. The composites exhibited extraction recoveries ranging from 80% to 90% for the studied pesticides. Compared to certain previously reported MSPE methods, this approach achieves equivalent or higher extraction recoveries in a shorter operation time, demonstrating enhanced efficiency and convenience. Good linearity of the target analytes was obtained within the range of 0.75-1500 µg L-1, with a determination of coefficient (R2) greater than 0.999. These findings contribute to the use of magnetic persimmon leaf biomass materials as effective and environmentally friendly adsorbents for pollutant determination in water samples.

Switchable hydrophilic solvent-based dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography for the determination of four types of sulfonylurea herbicides in soils.

In this study, switchable hydrophilic solvent-based dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography was developed for the determination of four sulfonylurea herbicides in soils. For the first time, the sample pretreatment was achieved due to the similar acid-base status of sulfonylurea herbicides and switchable hydrophilic solvent. In the extraction step, sulfonylurea herbicides were extracted as anions and transferred to an alkaline solution with switchable hydrophilic solvent anions. In the concentration step, two types of anions were transformed to their molecular state after the aqueous solution was acidified. In addition, the dispersion and microextraction processes were completed efficiently with the simultaneous formation of analytes and extractants. The factors affecting the extraction performance were optimized. Under the optimized conditions, good linearity was observed for each herbicide with correlation coefficients ranging from 0.9952 to 0.9978. The limits of detection were in the range of 0.1-0.2 µg/g. Moreover, the relative recoveries of the sulfonylurea herbicides at spiking levels of 0.5, 1, and 1.5 µg/g in soil samples were between 75 and 111% (relative standard deviations: 0.4-11.4%). Therefore, the proposed method in this study could be successfully applied to the analysis of four types of sulfonylurea herbicides in soil samples.

Magnetic cork composites as biosorbents in dispersive solid-phase extraction of pesticides in water samples.

This study assessed the use of magnetic biosorbents in dispersive solid-phase extraction with a gas chromatograph-electron capture detector for the determination of trifluralin, chlorothalonil, transfluthrin, bromopropylate, and bifenthrin in water samples. To our knowledge, this is the first time that magnetic cork composites are used as an adsorbent in dispersive solid-phase extraction. The advantages of magnetic cork composites include their density regulation and high surface areas. The magnetic composites can be recovered using a magnetic field for desorption purposes, which can improve the operation process and reduce the extraction time. Moreover, the parameters affecting the extraction performances were optimized. The method has a limit of detection between 0.30 and 2.02 µg L-1. Good linearities (R2 > 0.99) were obtained in the linear range of 1.00 to 2000 µg L-1. The relative recoveries of the analytes in tap water, river, and lake water samples spiked at different concentrations ranged between 90% and 104%, and the relative standard deviations were less than 7.1%. Therefore, this study showed that Fe3O4/cork magnetic composites can be used as efficient and eco-friendly biosorbents in dispersive solid-phase extraction for the determination of pesticides in water samples. The use of these composites contributes to the current trend of green chemistry.

Combining multi-isotope technology, hydrochemical information, and MixSIAR model to identify and quantify nitrate sources of groundwater and surface water in a multi-land use region.

Accurate identification of nitrate (NO3-) sources is the premise of non-point source pollution control in watersheds. The multiple isotope techniques (δ15N-NO3-, δ18O-NO3-, δ2H-H2O, δ18O-H2O), combined with hydrochemistry characteristics, land use information, and Bayesian stable isotope mixing model (MixSIAR), were used to identify the sources and contributions of NO3- in the agricultural watershed of the upper Zihe River, China. A total of 43 groundwater (GW) and 7 surface water (SFW) samples were collected. The results showed that NO3- concentrations of 30.23% GW samples exceeded the WHO maximum permissible limit level, whereas SFW samples did not exceed the standard. The NO3- content of GW varied significantly among different land uses. The averaged GW NO3- content in livestock farms (LF) was the highest, followed by vegetable plots (VP), kiwifruit orchards (KF), croplands (CL), and woodlands (WL). Nitrification was the main transformation process of nitrogen, while denitrification was not significant. Hydrochemical analysis results combined with NO isotopes biplot showed that manure and sewage (M&S), NH4+ fertilizers (NHF), and soil organic nitrogen (SON) were the mixed sources of NO3-. The MixSIAR model summarized that M&S was the main NO3- contributor for the entire watershed, SFW, and GW. For contribution rates of sources in GW of different land use patterns, the main contributor in KF was M&S (contributing 59.00% on average), while M&S (46.70%) and SON (33.50%) contributed significantly to NO3- in CL. Combined with the traceability results and the situation that land use patterns are changing from CL to KF in this area, improving fertilization patterns and increasing manure use efficiency are necessary to reduce NO3- input. These research results will serve as a theoretical foundation for controlling NO3- pollution in the watershed and adjusting agricultural planting structures.

Manual Reduction and Plaster External Fixation for the Treatment of Closed Total Talus Dislocation: Case Report and Literature Review.

BACKGROUND: Total dislocation of the talus from all its surrounding joints (talonavicular, tibiotalar, subtalar) is one kind of serious injury of the lower extremity with rare occurrence. It is usually accompanied by fractures of the talus and its periphery, as well as severe soft tissue injury, which is difficult to reset. Complications such as skin necrosis and infection are prone to occur in the early stage, and talus necrosis are prone to occur in the late stage, all of which aggravate disease severity and increase difficulties for its treatment. CASE PRESENTATION: Herein, we reported a case of right talus total dislocation accompanied by medial malleolus fracture and posterior tubercle fracture caused by traffic accident. One hour after injury, the doctor tried to perform manual reduction but failed. Then, we successfully performed manual reduction and plaster external fixation on this patient under anesthesia 6 h after injury, followed by the oral administration of Chinese medicine for 3 months. Twenty months of follow-up investigations revealed that no skin necrosis, talus dislocation, talus necrosis, or other complications occurred; no obvious joint degeneration was observed and the fractures of medial malleolus and talus healed well. MRI of ankle joint indicated the disappearance of ankle effusion caused by injury, and the bone marrow edema had also subsided at talus, medial malleolus, and lateral malleolus and calcaneus. Patient presented with no ligament relaxation, ankle instability, pain, swelling, or functional limitation of the injured limb. AOFAS score reached 100. Daily functions and recreation activities were recovered back to the normal level. CONCLUSION: For patients with closed total dislocation of the talus, fine therapeutic effects can be achieved by early closed manual reduction and plaster external fixation under anesthesia, in combination with oral Chinese herbal medicine afterwards. It is worthy of reference for clinicians.

On-site sample pretreatment: Natural deep eutectic solvent-based multiple air-assisted liquid-liquid microextraction.

Chemical protection is one of the most important methods to control forest pests. Since pesticides used in chemical protection might have significant adverse effects on aquatic organisms, it is essential to monitor and detect trace pesticides in environmental water. In this study, an on-site natural deep eutectic solvent-based multiple air-assisted liquid-liquid microextraction coupled with gas chromatography-electron capture detection was developed for determining triadimefon, bifenthrin, bromopropylate, and permethrin in water samples in the forest. A series of menthol-based deep eutectic solvents were synthesized for the first time to find green and efficient extractants. Moreover, a deep eutectic solvent with a 1:2 molar ratio of DL-menthol to citric acid was selected as the extractant due to its high stability and extraction performance. A portable modular array device based on air-assisted liquid-liquid microextraction was designed and manufactured to enable the simultaneous pretreatment of several samples. Although no electric equipment is required throughout the process, up to six samples were pretreated on-site within 20 min. Moreover, the average sample pretreatment time was less than 3.5 min, and the process was substantially simplified and enhanced. In addition, the parameters affecting the extraction performance were optimized. The extraction recoveries were in the range of 92-95% by using the optimized conditions, and the relative standard deviations of the intra-device, inter-device, intra-day, and inter-day factors were all less than 4.9%. The detection limits of the method ranged from 0.34 to 3.3 µg L-1. Good linearities (R2>0.999) were shown in the linear range of 1.13 to 2500 µg L-1 for the studied pesticides. Moreover, the proposed method was proved to be highly environmentally friendly by the Analytical Eco-Scale and Green Analytical Procedure Index. In summary, the proposed method is green, efficient, and flexible for on-site water sample pretreatment. The fact that tedious operations can be converted into standard operations provides a new perspective for on-site sample processing.

Effects of different fertilization modes on rice yield and quality under a rice-crab culture system.

Rice-crab culture is the characteristic rice ecological breeding model used in the Panjin area of Liaohe River Basin, China, and it can improve the ecological environment and create increased economic benefits. From a food perspective, both rice yield and quality, which are closely related to the fertilization mode, should be considered. However, the effect of different fertilization modes on rice quality has not been comprehensively investigated in this co-culture system. This study investigated the effects of three fertilization modes(FP1, FP2, and OPT) divided according to different fertilization types and methods on rice yield and quality, and set up a non-fertilized control group. In the rice-crab culture system, FP2 used fewer fertilizers and had a lower economic cost, and the yield was only slightly less than that of OPT(highest yield) but there was no statistical difference. FP2 elicited the best appearance quality and better cooking and eating quality among all treatment modes. Compared with CK, three fertilization modes significantly increased the protein content in rice and decreased the amylose content, which would lead to the deterioration of rice eating quality. However FP2 had the least protein increase and the least amylose reduction. There was no significant change in crude fat and starch content. Therefore, the FP2 fertilization mode was the best choice for the rice-crab culture system, as it significantly improved rice yield and increased rice quality at a relatively low cost.