Drug (Fenbufen, FBF)-loaded poly( d , l -lactide-co-glycolide) (PLGA) and PLGA/gelatin nanofibrous scaffolds were fabricated via electrospinning technique. The influences of gelatin content, fiber arrangement, crosslinking time and pH value of the buffer solution on FBF release behavior of the resulting nanofibrous scaffolds were investigated, with the corresponding FBF-loaded PLGA and PLGA/gelatin solvent-cast films as controls. The release rate of FBF was found to be increased with the increment of gelatin content for all the composite samples, and the FBF release rate of aligned nanofibrous scaffold was lower than that of randomly oriented scaffold. Moreover, the crosslinking treatment depressed effectively the burst release of FBF at initial release stage of PLGA/gelatin (9/1) nanofibrous scaffold. In addition, the pH value of the buffer solution could change the physical state of the polymer and affect the FBF release rate.
Zhiwei Wang,Junhui Chen,Tianrong Zhan,Xiuping He,Baodong Wang
Neonicotinoids (NEOs) and fipronil (FIP) are insecticides that are widely used in modern agriculture and have received considerable attention in recent years due to their adverse effects on non-target organisms in the environment. In the present study, a new method to simultaneously detect eight common NEO insecticides and FIP and its three transformation products (FIPs) in sediments was developed using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) based on a combined pretreatment of continuous solvent extraction (CSE) and solid phase extraction (SPE). Under optimized conditions, 5.0 g of freeze-dried sediment samples were initially extracted with methanol (20 mL)–methanol (15 mL)–water (20 mL) in sequence, and then the extract was cleaned with hydrophilic–lypophilic balance SPE cartridges, and HPLC-MS/MS analysis was conducted. The established method was validated to be sensitive, linear, accurate, and precise. The limits of detection (LOD) and limits of quantification (LOQ) of target compounds were 0.012–0.055 μg/kg d.w and 0.031–0.091 μg/kg d.w, respectively. Good linearity ( R 2 > 0.990) was observed between 4.0 × 10 −2 and 20.0 μg/kg d.w. The recovery rates of all target insecticides were between 75.5% and 98.5%, and the relative standard deviations (RSD) were all less than 15.0% at the low, medium, and high spiked levels. Finally, the optimized method was applied to analyze 12 target insecticides in the sediments obtained from Jiaozhou Bay of China and its main inflow rivers. Acetamiprid, thiamethoxam , fipronil sulfide, and fipronil sulfone were detected in the river sediment samples at the concentration from
In this work, Friedel-Crafts alkylation was successfully applied to prepare a magnetic ionic liquid hypercrosslinked polymer composite (Fe 3 O 4 @IL-HCP), which was subsequently employed as magnetic solid-phase extraction (MSPE) adsorbent for the isolation and enrichment of trace non-steroidal anti-inflammatory drugs (NSAIDs). The developed composite was comprehensively characterized using various techniques, with the results indicating that it possessed high saturation magnetization (39.44 em g − 1 ), large specific surface area (175 m 2 g − 1 ), and high adsorption capacity for NSAIDs. The adsorption behavior and mechanisms were also investigated in detail. NSAIDs were adsorbed onto the Fe 3 O 4 @IL-HCP sorbent via a heterogeneous multilayer process consisting of hydrogen bonding and π-π and electrostatic interactions. Additionally, the composite's large surface area and multiple active sites enabled extraction equilibrium within 6 min. By coupling with high performance liquid chromatography (HPLC), the developed MSPE/HPLC method was applied for the determination of selected NSAIDs in water and urine samples. The developed method displayed wide linear ranges, low limits of detection (0.12–0.30 ng mL −1 and 0.15–1.5 ng mL −1 in water and urine samples, respectively), sufficient recoveries (92.8–109%), and good precision (relative standard deviations ≤ 4.6%). Thus, the findings of this work provide an appealing alternative for the extraction and determination of trace NSAIDs in environmental water and biological samples.
危险品化学品经营许可证（带存储）