Enhanced cleanup efficiency hydroxy functionalized-magnetic graphene oxide and its comparison with magnetic carboxyl-graphene for PRiME pass-through cleanup of strychnine and brucine in human plasma samples

Preparation and Characterization of Nano-Fe3O4 and Its Application for C18-Functionalized Magnetic Nanomaterials Used as Chromatographic Packing Materials

A new type of magnetic nanomaterial with Fe₃O₄ as the core and organic polymer as the shell was synthesized by seed emulsion polymerization. This material not only overcomes the problem of insufficient mechanical strength of the organic polymer, it also solves the problem that Fe₃O₄ is prone to oxidation and agglomeration. In order to make the particle size of Fe₃O₄ meet the requirement of the seed, the solvothermal method was used to prepare Fe₃O₄. The effects of the reaction time, amount of solvent, pH value, and polyethylene glycol (PEG) on the particle size of Fe₃O₄ were investigated. In addition, in order to accelerate the reaction rate, the feasibility of preparing Fe₃O₄ by microwave was studied. The results showed that under the optimum conditions, the particle size of Fe₃O₄ could reach 400 nm and had good magnetic properties. After three stages of oleic acid coating, seed emulsion polymerization, and C18 modification, the obtained C18-functionalized magnetic nanomaterials were used for the preparation of the chromatographic column. Under optimal conditions, stepwise elution significantly shortened the elution time of sulfamethyldiazine, sulfamethazine, sulfamethoxypyridazine, and sulfamethoxazole while still achieving a baseline separation.

Brucine-Induced Neurotoxicity by Targeting Caspase 3: Involvement of PPARγ/NF-κB/Apoptosis Signaling Pathway

Brucine, a weak alkaline indole alkaloid, is one of the main bioactive and toxic constituents of Strychnos nux-vomica L., which exerts multiple pharmacological activities, such as anti-tumor, anti-inflammatory, and analgesic effect. However, its potential toxic effects limited its clinical application, especially central nervous system toxicity. The present study was designed to investigate the neurotoxicity and mechanism of brucine. Our results showed that brucine significantly induced Neuro-2a cells and primary astrocyte death, as evidenced by MTT assay and LDH release. Moreover, transcriptome analysis indicated that PPAR/NF-κB and apoptosis signaling pathways were involved in the brucine-induced cytotoxicity in Neuro-2a cells. Subsequently, in fact, brucine evidently inhibited PPARγ and promoted phosphorylation of NF-κB. Furthermore, PPARγ inhibitor aggravated the neurotoxicity, while NF-κB inhibitor substantially reversed brucine-induced neurotoxicity. Moreover, brucine also significantly induced neuronal apoptosis and triggered increase in ratio of Bax/Bcl-2 and level of cleaved caspase 3, as well as its activity as evidenced by TUNEL staining and Western blot. Furthermore, molecular docking analysis predicted that brucine directly bound to caspase 3. Intriguingly, a caspase 3 inhibitor (Z-DEVE-FMK) largely abolished the neurotoxicity of brucine. Our results reveal that brucine-induced neurotoxicity via activation of PPARγ/NF-κB/caspase 3-dependent apoptosis pathway. These findings will provide a novel strategy against brucine-induced neurotoxicity.

Nanomaterials with Excellent Adsorption Characteristics for Sample Pretreatment: A Review

Sample pretreatment in analytical chemistry is critical, and the selection of materials for sample pretreatment is a key factor for high enrichment ability, good practicality, and satisfactory recoveries. In this review, the recent progress of the sample pretreatment methods based on various nanomaterials (i.e., carbon nanomaterials, porous nanomaterials, and magnetic nanomaterials) with excellent adsorption efficiency, selectivity, and reproducibility, as well as their applications, are presented. Due to the unique nanoscale physical–chemical properties, magnetic nanomaterials have been used for the extraction of target analytes by easy-to-handle magnetic separation under a magnetic field, which can avoid cumbersome centrifugation and filtration steps. This review also highlights the preparation process and reaction mechanism of nanomaterials used in the sample pretreatment methods, which have been applied for the extraction organophosphorus pesticides, fluoroquinolone antibiotics, phenoxy carboxylic acids, tetracycline antibiotics, hazardous metal ions, and rosmarinic acid. In addition, the remaining challenges and future directions for nanomaterials used as sorbents in the sample pretreatment are discussed.

Nano-titania modified cupric-based metal–organic frameworks for the on-line pass-through cleanup of phenothiazine drugs and metabolites in human plasma

SEM (A) and TEM (B) images of NTMCu-MOFs.

A rapid method for the simultaneous stereoselective determination of the triazole fungicides in tobacco by supercritical fluid chromatography-tandem mass spectrometry combined with pass-through cleanup

This work presents a simple, rapid and green chiral analysis method for five triazole fungicides (penconazole, tebuconazole, triadimefon, myclobutanil, and triadimenol) in tobacco, by which the samples were cleaned up by the novel pass-through solid phase extraction and subsequently the stereoisomers were separated and determined by the supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS). Optimized separation of the stereoisomers was achieved on an ACQUITY UPC2 Trefoil AMY 1 column within 6 min. Under fortified concentration levels of 0.1, 0.5 and 2.0 mg/kg, the mean recoveries were 82.8-106.6%, the intra-day relative standard deviations (RSDs) were 1.1-6.6%, and the inter-day RSDs were 2.5-5.6%. The correlation coefficient was greater than 0.9926 for all studied analytes within the range of 10-500 ng/mL. The limits of detection (LODs) for all stereoisomers ranged from 0.26 μg/kg to 3.24 μg/kg. The established method was subsequently successfully applied to analyze authentic samples, confirming that this method is a novel, rapid and environmentally friendly method for the stereoselective separation of triazole fungicides in tobacco.

Recent applications of magnetic solid phase extraction in sample preparation for phytochemical analysis

Sample preparation such as isolation and pre-concentration is a crucial step for the phytochemical analysis. Magnetic solid-phase extraction (MSPE) has received considerable attention, mainly due to its phase separation more conveniently by facile magnetic decantation as compared to traditional SPE. This review focused on the recent applications of MSPE in sample preparation for the analysis of phytochemical compounds in plants, biological samples and Chinese herbal preparations. In addition, the enzymes immobilized on the magnetic materials and used for the biospecific extraction of enzyme inhibitors were also discussed. The information summarized in this article may provide a reference to the further applications of MSPE in phytochemical analysis.

Rapid Analysis of Four Amphetamines in Urine by Self-Made Pipette-Tip Solid-Phase Extraction Followed by GC-MS/MS

A simple and rapid pipette-tip solid-phase extraction (PT-SPE) procedure with derivatization prior to gas chromatography triple quadrupole mass spectrometry analysis is developed for the simultaneous determination of amphetamine (AMP), methamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA) and 3,4-methylenedioxymethamphetamine (MDMA) in urine samples. The PT-SPE procedure using self-made sorbent could extract drugs within 6 min from 100-μL urine samples, requiring low solvent-consumption (<2.0 mL). Besides, the self-made pipette tip could be reused at least five times. Under optimized conditions, the recoveries of four amphetamines at spiked levels (low, medium and high) ranged from 87.7 to 110.4%, with relative standard deviations < 9.5%. The limit of detections and limit of quantifications for AMP, MA, MDA and MDMA were in the range of 2.52–8.25 ng⋅mL−1 and 8.4–27.5 ng⋅mL−1, respectively. Validation results show that the proposed method is suitable for the quantitation of amphetamines and has been successfully applied in the urine samples of suspected drug abusers.

Application of petal-shaped ionic liquids modified covalent organic frameworks for one step cleanup and extraction of general anesthetics in human plasma samples

Here, the novel petal-shaped ionic liquids modified covalent organic frameworks (PS-IL-COFs) particles have been synthesized by using ionic liquids as modifying agent, which could be beneficial to avoid the aggregation of COFs during the preparation and improve its dispersing performance. The novel PS-IL-COFs particles have been used and evaluated in the one step cleanup and extraction (OSCE) procedure for human plasma prior to the analysis of 3 general anesthetics by liquid chromatography-tandem quadrupole mass spectrometry (LC-MS/MS). In the OSCE procedure, human plasma samples are directly mixed with extraction solvent and PS-IL-COFs particles, and the extraction and cleanup procedure have been carried out simultaneously. Compared with the Oasis PRiME HLB cartridge method, the OSCE procedure using PS-IL-COFs particles as sorbents is much more effective for the minimization of ion suppression resulted from blood phospholipids. Under optimal conditions, the PS-IL-COFs particles show higher cleanup efficiency of 3 general anesthetics with recoveries in the range of 82.5%-115%. The limits of quantification (LOQs) for propofol, ketamine and etomidate are 0.18 μg/L, 0.15 μg/L and 0.016 μg/L, respectively. Validation results on linearity, specificity, precision and trueness, as well as on the application to analysis of general anesthetics in a case of a 54-year-old female suffered gallstone demonstrate the applicability to clinical studies.