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Microplastics (MPs) can act as carriers of environmental arsenic species into the stomach with food and release arsenic species during digestion, which threatens human health. Herein, an integrated dynamic stomach model (DSM)-capillary electrophoresis-inductively coupled plasma mass spectrometry (CE-ICPMS) is developed for online monitoring of the release and transformation behaviors of arsenic species loaded on MPs (As-MPs) in the simulated human stomach. The 3D-printed DSM with a soft stomach chamber enables the behaviors of gastric peristalsis, gastric and salivary fluid addition, pH adjustment, and gastric emptying (GE) to be controlled by a self-written program after oral ingestion of food with As-MPs. The gastric extract during digestion is introduced into the spiral channel to remove the large particulate impurity and online filtered to obtain the clarified arsenic-containing solution for subsequent speciation analysis of arsenic by CE-ICPMS. The digestion conditions and pretreatment processes of DSM are tracked and validated, and the release rates of As-MPs digested by DSM are compared with those digested by the static stomach model and DSM without GE. The release rate of inorganic arsenic on MPs is higher than that of organic arsenic throughout the gastric digestion process, and 8% of As(V) is reduced to As(III). The detection limits for As(III), DMA, MMA, and As(V) are 0.5–0.9 µg L–1using DSM-CE-ICPMS, along with precisions of =8%. This present method provides an integrated and convenient tool for evaluating the release and transformation of As-MPs during human gastric digestion and provides a reference for exploring the interactions between MPs and metals/metalloids in the human body.

Using phenyliodine diacetate as an oxidant and nickel acetate as a promoter, a wide range of unsymmetric thiosulfonates could be furnished easily in moderate to excellent yields starting from N-substituted O-thiocarbamates and sodium sulfinates. This protocol features mild conditions, short reaction times, and high atomic utilization, which can provide an alternative method for the synthesis of unsymmetric thiosulfonates. In addition, the reaction could be scaled up on a gram scale, showing potential application value in industry.

Speciation analysis of arsenic in urine is essential for the studies of arsenic metabolism and biological effects, but the unstable arsenic species represented by MMAIIIand DMAIIIpose a huge challenge to analytical accuracy. Herein, a novel urine self-sampling (USS) kit combined with an automated preparation-sampler (APS) device is rationally designed and used for convenient analysis of arsenic metabolites by high-performance liquid chromatography–inductively coupled plasma mass spectrometry (HPLC–ICPMS). The subject can collect urine into a sampling vial at home and use a homemade syringe to pump argon to displace oxygen in the vial, thereby inhibiting the oxidation of MMAIIIand DMAIII. After USS and transportation, the sampling vial is loaded directly onto the APS device, where the urine sample can be automatically mixed with diluent, filtered, and loaded into HPLC–ICPMS for arsenic speciation analysis under anaerobic conditions. For a single sample, the sampling time and the analysis time are <8 and <18 min, respectively. The recoveries of MMAIIIand DMAIIIin urine over 24 h at 4 °C are 86 and 67%, surpassing the conventional sampling method by 28 and 67%, respectively. When the APS is coupled to HPLC–ICPMS, the detection limits of AsC, iAsIII, MMAIII, DMAV, MMAV, DMAIII, and iAsVare 0.03–0.10 μg L–1with precisions of <10%. The present method provides a convenient and reliable tool for the storage and analysis of unstable arsenic species in urine and lays the foundation for studying the metabolic and biological effects of methylated trivalent arsenicals.

A simple and efficient method for the synthesis of unsymmetrical disulfides is reported. Using sodium sulfites and 2-mercaptobenzo heterocyclic compounds as starting materials, the unsymmetrical sulfur–sulfur bonds could be quickly constructed in the PPh3/I2reaction system under transition–metal-free conditions. This protocol has the advantages of mild reaction conditions, easily available starting materials, and wide substrate scope, showing potential synthetic value for the synthesis of a diversity of biologically or pharmaceutically active compounds.

Dried blood spot (DBS) detection has the advantages of small blood collection, convenience, and reliability, which provides a possibility for large-scale evaluation of arsenic exposure in human population. Herein, a facile Lego-spinner pretreatment device is rationally designed for speciation analysis of arsenic in DBSs by ion chromatography-inductively coupled plasma-mass spectrometry (IC-ICP-MS). In the mixing mode of the Lego-spinner, the magnetic stir bar in the centrifuge tube rotates under a magnetic field to assist the dispersive extraction of arsenic species in the DBS with reagents. In the centrifugation mode of the Lego-spinner, the arsenic extract is separated from the blood matrix for the subsequent IC-ICP-MS analysis. For the DBS prepared from 80 μL of whole blood, the whole pretreatment operation can be completed within 25 min. The detection limits of arsenobetaine, arsenite, dimethylarsenate, monomethylarsonate, and arsenate in the DBS are 0.09–0.15 μg L–1, and precisions are <11%. The concentrations of these five arsenic species are highly correlated between whole blood and the DBS (r2> 0.97), and Bland–Altman analysis indicates that the concentration difference of arsenic species between whole blood and the DBS is within ±20%. The DBS sampling approach can effectively preserve arsenic species for at least 30 days at 4 °C, and the contents of arsenic species in the DBS prepared from capillary blood are in a reasonable agreement with those of venous whole blood (gold standard). This Lego-spinner provides a handy and efficient tool for fast extraction of arsenic species in DBSs, facilitating the in-depth study of arsenic migration and transformation in the human body.

In order to ensure the safe operation of the ship in the medium-voltage grid, transformer protection is particularly important. Using Matlab/Simulink, this paper established transformer and its differential protection simulation model of the medium-voltage ship. To achieve differential protection function, this paper uses the M-file to program the differential protection S-function. The simulation results indicate that the differential protection models can achieve their protection functions and have better quick-acting and stability.

A novel gem-difluoromethylenated castanospermine analogue was designed and synthesized. The key steps involve substitution cyclization reaction and RCM reaction to construct the aza fused bicyclic framework.