Journal of Chromatography B最新文献

Liquid chromatography coupled with mass spectrometry (LC-MS) has been tremendously used for screening purposes in forensic toxicology, because of their great adaptability and reasonable time/resource consumption. Herein, a fully validated method based on liquid-liquid extraction (LLE) in human whole blood, by a multiple reaction monitoring (MRM) analysis through LC-MS/MS, is described. The proposed method simultaneously detects 100 analytes (plus three deuterated internal standard compounds) belonging to many different classes, including drugs of abuse, prescription and over-the-counter drugs commonly involved in poisoning and medical malpractice cases in our territory, as well as certain new psychoactive substances (NPS) and toxic substances potentially associated with adverse effects. The optimised LLE employs one extraction step of 200 μL blood using 0.1 M HCl methyl-tert-butyl-ether (MTBE) (acidified with concentrated HCl) proved to be suitable for the extraction of basic and neutral substances; as a reconstitution solvent a mixture of 88:12v/v, 0.1 % formic acid in 10 mM aqueous ammonium acetate, pH 3.5: 0.1 % formic acid in acetonitrile was used, yielding satisfactory recoveries for all analytes. The method was sensitive, showing low LOD/ LOQ for all substances ranging from 0.01 to 5/ 0.05–20 ng/mL, respectively. Linearity ranged between 0.05–500 ng/mL (R² = 0.9811–0.9995), and the inter- and intra-day precisions ranged between 3–15 % and 7–18 %, respectively. Accuracy was evaluated in terms of percentage recovery, lying within acceptable range. The matrix effect expressed as ion suppression/enhancement of each analyte was in the range ±25 % for all analytes. Post-preparative stability of analytes was higher than 85 %, while no carryover between runs was observed. The developed method has been successfully applied in routine toxicological analyses for the analysis of biological samples from clinical and autopsy cases.

In this work, an imidazolium-based poly(ionic liquid) (poly(1-dodecyl-3-vinyl-imidazolium bromide) functionalized magnetic three-dimensional graphene oxide (Fe₃O₄@3D-GO@poly(ImC₁₂⁺Br⁻)) was synthesized via a vacuum freezing-drying method and used as a magnetic solid phase extraction (MSPE) adsorbent for the efficient extraction of pyrethroid pesticides from tea samples. The prepared Fe₃O₄@3D-GO@poly(ImC₁₂⁺Br⁻) was confirmed by scanning electron microscopy (SEM), Fourier transform infrared spectrometry (FT-IR), vibrating sample magnetometer (VSM) and X-ray photoelectron spectrogram (XPS). Due to its large specific surface area and the ability to offer multiple intermolecular interactions, including π-π stacking, hydrophobic and hydrogen bond interactions, the prepared Fe₃O₄@3D-GO@poly(ImC₁₂⁺Br⁻) showed high extraction efficiency for pyrethroids. The experimental parameters were optimized by a combination of single-factor method and Box-Behnken design to improve the extraction efficiency. Under the optimum conditions, coupled with high performance liquid chromatography (HPLC), a sensitive analytical method was developed for the determination of pyrethroids, and the proposed method showed wide linear ranges (1.00–100 μg L⁻¹) with correlation coefficients (R) ranging from 0.9980 to 0.9994, low limits of detection (0.100 μg L⁻¹) and good repeatability with intra-day relative standard deviations (RSDs) in the range of 2.90–5.53 % and inter-day RSDs in the range of 1.83–7.76 %. Moreover, the developed method was successfully applied to the determination of pyrethroids in tea samples and satisfactory recoveries ranging from 82.37 % to 114.34 % were obtained. The results showed that the developed Fe₃O₄@3D-GO@poly(ImC₁₂⁺Br⁻) was an ideal, effective and selective material for the extraction and enrichment of pyrethroids from tea samples.

Hypericum japonicum is a traditional folk medicine with various bioactivities such as hepatoprotective, antioxidant, and anti-tumorous. The antioxidant effect of H. japonicum is one of the most prominent effects due to its responsibility for many of its activities. To clarify active natural substance, the antioxidant properties of H. japonicum were preliminarily assessed by ferric reducing–antioxidant power (FRAP), 2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) and Oxygen radical absorbance capacity (ORAC), as well as superoxide dismutase (SOD). Then, a straightforward and effective method named online liquid extraction-high performance liquid chromatography combined with ABTS antioxidant assay and mass spectrometry (OLE-HPLC-ABTS/Q-TOF-MS) was developed to swiftly and directly discover the antioxidants in H. japonicum. Using mobile phase as extraction and separation reagent, coupled with online activity analysis and compounds identification by high-resolution MS, the online system enables rapid screening of natural antioxidant bioactives from complex mixture. By using it, a total of 9 compounds including flavonoids and phenolic acids characterized by retention time, precise mass, and fragmentation ions in MS/MS spectra showed antioxidant action. Finally, the antioxidant and SOD activity of main found active compounds were validated by in vitro experiment assay and molecular docking. In summary, these results suggested that H. japonicum could be considered as a potential source of natural antioxidants, and the online integrated system might become a promising candidate for the natural antioxidants discovery in the future.

Herein, we describe the utilization of an ionic liquid (IL)/Carbowax 20 M−functionalized sol–gel sorbent for the capsule phase microextraction of doxycycline in authentic human urine samples. This green sample preparation method combines stirring and filtration in a single, standalone sample preparation device, streamlining the sample preparation process. Additionally, it provides rapid extraction kinetics and high extraction efficiency. The experimental conditions (i.e. sorbent type, sample pH and volume, extraction time, ionic strength, elution solvent, and volume) affecting the extraction efficiency of the analyte were studied and optimized. The method was linear in the range of 0.1 – 5.0 μg/mL with a coefficient of determination higher than 0.995. The achieved LOD was found to be 0.02 μg/mL while the lower limit of quantitation (LLOQ) was 0.1 μg/mL. The IL/Carbowax 20 M−functionalized microextraction capsules were reusable at least 30 times for urine samples. The relative recoveries (% RR) ranged between 93.4 – 115.9 % while the precision (expressed as % RSD) was better than 8.1 % in all cases. The robustness of the microextraction procedure and the instrumental HPLC method were separately investigated using Plackett-Burman experimental designs. The analytical protocol demonstrated cost-effectiveness, ease of handling, and speed, leading to increased sample throughput. The green character of the developed method was evaluated using the Green Analytical Procedure Index (GAPI) and Blue Applicability Grade Index (BAGI). Finally, the method’s applicability was demonstrated by analyzing authentic human urine samples after oral administration of a doxycycline-containing pharmaceutical formulation.

Taletrectinib is a potent selective ROS and pan-NTRK tyrosine kinase inhibitor (TKI) and has been developed to treat non-small cell lung cancer (NSCLC). To facilitate pharmacokinetic and toxicokinetic studies of taletrectinib, we developed a procedure for ultra-high-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) to detect the plasma level of taletrectinib in dogs. This assay procedure was validated in compliance with FDA guidance. The dog plasma samples were spiked with internal standard (IS), followed by protein precipitation, and analyzed using a Waters ACQUITY BEH C₁₈ column coupled to a Thermo triple quadrupole mass spectrometer. Separation was executed using the acetonitrile-0.1 % formic acid solution with gradient elution, at a flow rate of 0.4 mL/min. Taletrectinib and IS were monitored by multiple reaction monitoring (MRM) with m/z 406.2 > 349.2 and m/z 441.2 > 138.1, respectively. The procedure demonstrated excellent linearity with a correlation coefficient greater than 0.999 within the concentration range of 0.2–200 ng/mL. The inter- and intra-day accuracy ranged from −5.25 % to 5.26 %, and the precision was below 6.39 %. Acetonitrile-mediated protein precipitation showed high extraction efficiency and a recovery above 85 %. The procedure was then applied to quantify taletrectinib in beagle dog plasma after oral and intravenous doses and achieved success. The obtained pharmacokinetic parameters indicated high bioavailability of taletrectinib (>85 %) and extensive tissue distribution (>40 L/kg).

A capillary high-performance liquid chromatography (HPLC) system equipped with a dual-electrode detector utilizing track-etched membrane electrodes (TEMEs) was combined with a microdialysis sampling setup. The electrochemical detector benefits from the high electrolysis efficiency of TEMEs, allowing for calibration-free coulometric detection and simplifying data analysis to determine the dopamine recovery through a dialysis probe. Additionally, this system was used for in vivo monitoring of dopamine in the right striatum of a mouse brain. Temporal changes in dopamine levels, including an exponential decay immediately after the dialysis probe insertion and an excess release of dopamine induced by a high concentration of potassium ions, confirmed the system’s proper operation. Furthermore, subsequent measurements following the intraperitoneal injection of mirtazapine showed no increase in dopamine levels in the right dorsal striatum. The dual-electrode system displayed characteristic dopamine detection behavior, with anodic and cathodic peak pairs indicative of reversible electrochemical reactions. This capability facilitated the identification of the dopamine peak within the complex chromatogram of the mouse brain dialysate. The consistency between dopamine collection efficiency from standard solutions and dialysate indicated the absence of interfering electroactive substances overlapping with the dopamine peak in the chromatogram. This integrated analysis system successfully tracked temporal fluctuations in dopamine concentration within the mouse brain.

Background

Rheumatoid arthritis (RA) is an autoimmune disease characterized by synovitis, which can lead to joint deformity. Acupuncture treatment stimulates specific acupoints to adjust qi and blood function, relieving joint inflammation and pain.

Methods

Ultra-high performance liquid chromatography-mass spectrometry (UPLC-QTOF-MS) was utilized for non-targeted metabolomics analysis of plasma samples from the blank group, Adjuvant-Induced Arthritis (AIA) model mice model mice group, and acupuncture group. Metabolite hierarchical clustering analysis, multivariate statistical analysis, standardized processing, principal component analysis (PCA), partial least squares-discriminant analysis (PLS-DA), and other methods were employed to identify targeted metabolites affected by acupuncture treatment in AIA mice. The related metabolic pathways were analyzed using KEGG pathway.

Results

Histopathological results demonstrated that acupuncture at Zusanli point (ST 36) significantly improved the inflammatory response in AIA mice. The PCA score plot indicated relatively close sample clustering within each group with significant differences observed between the four groups, confirming successful establishment of the AIA animal model with metabolic disorders occurring. Acupuncture treatment effectively corrected these metabolic disorders. Plasma metabolomics identified a total of 10 differential metabolites primarily associated with arachidonic acid and pentose phosphate metabolic pathways.

Conclusions

Acupuncture at ST36 can significantly improve the inflammatory response in AIA mice through modulation of arachidonic acid and pentose phosphate metabolic pathways.

Upadacitinib is an oral Janus Kinase inhibitor used for the treatment of rheumatoid arthritis. This research focuses on the forced degradation study of upadacitinib and the characterization of its degradation impurities. Upadacitinib was subjected to various degradation conditions such as hydrolysis (acid, base, neutral), oxidation, thermal, and photolysis according to International Council for Harmonisation guidelines. Twelve degradation impurities of upadacitinib were observed under oxidation (H₂O₂, AIBN, Fenton’s reagent) and photolysis (UV light). Zeneth software was used to predict the in silico degradation profile. High-performance liquid chromatography was used to separate the observed degradation impurities with ammonium formate (pH 3.63) and acetonitrile as mobile phases on an Agilent Zorbax Eclipse plus C18 column (4.6 × 250 mm, 5 µm). The separated degradation impurities were characterized by using high resolution mass spectrometry. The accurate masses obtained from LC-HRMS/MS were used to determine the structures of all the degradation impurities. A suitable mechanism for the formation of degradation impurities was proposed. DEREK Nexus and SARAH Nexus were used for the in silico toxicity and mutagenicity assessments.