Chromatographia最新文献

Ciwujia tablet (CT) is extensively utilized in China to enhance sleep quality and manage cardiovascular and cerebrovascular disorders. This study presents a comprehensive strategy for evaluating the quality of CT from various manufacturers by integrating qualitative identification, quantitative analysis, and multivariate statistics. When identifying small molecules, traditional manual methods should be transformed into more efficient approaches that leverage software to facilitate complex analyses. Among the fragmentation software evaluated, MS-Finder distinguished itself as particularly effective. Following data acquisition through UHPLC-Orbitrap Fusion Tribrid mass spectrometry, the chemical characterization of the CT was performed using MS-DIAL, MS-Finder, and GNPS molecular networking techniques. In total, 80 compounds were identified in positive ion mode and 92 compounds in negative ion mode. Subsequently, parallel reaction monitoring (PRM) was used to analyze the eight key compounds identified in CT quantitatively. All eight components exhibited good linearity within their respective mass concentration ranges (r ≥ 0.99) and met the relevant requirements for precision, repeatability, and stability. Recovery rates ranged from 99.16% to 101.07%. Finally, multivariate statistical methods, such as hierarchical cluster analysis (HCA), principal component analysis (PCA), and orthogonal partial least squares discriminant analysis (OPLS-DA), were conducted using SIMCA 14.1 software to elucidate the differences among CT samples from ten manufacturers. The results indicate that the method established in this study can perform sensitive and efficient qualitative and quantitative analysis of the chemical components in CT. It is a promising approach for exploring compounds and provides new research directions and scientific support for future studies on quality control measures for CT.

Graphical Abstract

The sorption of the light saturated hydrocarbons (C1–C4) and CO₂ on a divinylbenzene and 4-vinylbenzyl chloride copolymer was studied using inverse gas chromatography in the temperature range 323.15–383.15 K. The values of the specific retention volume (V_g), as well as the enthalpy of adsorption change (– ∆H_CH4 = 20.74 kJ mol⁻¹; – ∆H_CO2 = 24.53 kJ mol⁻¹; – ∆H_C2H6 = 27.40 kJ mol⁻¹; – ∆H_C3H8 = 33.78 kJ mol⁻¹; – ∆H_C4H10(i) = 37.04 kJ mol⁻¹; – ∆H_C4H10(n) = 39.27 kJ mol⁻¹), entropy of adsorption change (– ∆S_CH4 = 77.16 J mol⁻¹ K⁻¹; – ∆S_CO2 = 73.12 J mol⁻¹ K⁻¹; – ∆S_C2H6 = 77.45 J mol⁻¹ K⁻¹; – ∆S_C3H8 = 85.34 J mol⁻¹ K⁻¹; – ∆S_C4H10(i) = 88.71 J mol⁻¹ K⁻¹; – ∆S_C4H10(n) = 91.77 J mol⁻¹ K⁻¹) and Gibbs free energy of adsorption change (∆G) of the above gases adsorption were determined. The obtained thermodynamic parameters demonstrate the potential for efficiently separating the gases under study, indicating the copolymer’s ability to separate the main components of natural gas.

Ethylene/1-olefin copolymers have held industrial significance for a considerable period. A series of copolymers with identical molar mass and varying 1-hexene levels were synthesized using supported metallocene catalyst. Various analytical techniques were used to characterize the copolymers, focusing on the effect of increasing 1-hexene content on their chemical properties, specifically chemical composition distribution (CCD). Initially, the investigations carried out by differential scanning calorimetry (DSC) revealed broad and asymmetric thermograms with the presence of a distinct shoulder in samples with higher 1-hexene content. Furthermore, HT-GPC with IR5 detector revealed uniform chemical composition (1-hexene concentration) along the molar mass axis. Examination of the chemical composition distribution (CCD) was conducted using two variants of high-temperature liquid adsorption chromatography (HT-LAC), namely solvent gradient interaction chromatography (SGIC) and thermal gradient interaction chromatography (TGIC). Initial testing by employing solvents common to HT-LAC showed that the elution behavior did not correspond with the distinct thermal properties DSC. In the next step, new desorption-promoting solvents were identified using a recent approach that integrates structure retention relationships (SRR), a measure of solvent–stationary phase interactions, with Hansen solubility parameters (HSP), assessing polymer–solvent interactions. The broad and asymmetric CCD in samples with higher SCB, characterized by a main peak and a shoulder, was confirmed by SGIC using newly identified desorption-promoting solvents identified via the SRR–HSP method. This CCD profile was also corroborated by TGIC using a binary solvent mixture as the mobile phase.

Isoprenaline (IPN) HCl is a nonselective β‐adrenergic agonist used in treating heart block and low heart rate. To determine the right percentage of isoprenaline HCl in a pharmaceutical the injectable solution, an RP-HPLC method was designed in the scope of this study. Chromatographic separation was carried out on an Inertsil C18 column (150 × 4.6 mm, 2.7 µm) at 40 °C using methanol/0.1% o-phosphoric acid (v/v) (5:95) as the mobile phase at a flow rate of 1.0 mL/min. A UV detector was operated at 280 nm and the calibration curves were linear over a concentration range of 2.50–7.50 µg/mL. The recovery values were calculated to be 99.13–100.34%. This method was successfully applied to quantify IPN HCl in injectable solutions. In addition, the method was validated according to the requirements of ICH guidelines. The proposed method for the determination of IPN was applied to pure and pharmaceutical preparations. Optimized geometric structures were drawn with GaussView 5. Then, the optimum geometric structures with the lowest energy were found with the Gaussian 09 program. These results will determine the most appropriate reaction pathways. Fragmentation patterns and degradation mechanisms initiated by hydroxyl radical attacks were evaluated in both gas and aqueous phases, incorporating solvation effects using the COSMO model. The molecular interactions of isoprenaline with β-adrenergic receptors were studied by molecular docking calculations and MD minimization in comparison with the natural ligands of these receptors, epinephrine and norepinephrine.

Natural antibodies are antibodies present in the sera of all individuals in the absence of any immunization. Carbohydrate-binding antibodies are a very important part of such antibodies and are considered molecules for the recognition and removal of dysfunctional or malignant cells. In this regard, carbohydrate-specific antibodies in donor plasma can be considered a source for the preparation of such antibodies as potential therapeutic agents for the prevention of tumor and viral diseases. A new approach in affinity chromatography was used to purify carbohydrate-specific antibodies from the IgG fraction of human plasma. The affinity carrier was prepared by attaching milk glycoproteins to a P10 polyacrylamide matrix using glutaric dialdehyde. In contrast to methods using the direct binding of different sugars, this approach is simpler and does not lead to the disruption of antigenic determinants as a result of their covalent binding. Using this approach, 3–4 mg of specific antibodies were obtained from 150 mg of the IgG fraction.

Chemotaxonomy, based on pigment markers, has significantly enhanced the monitoring efficiency of phytoplankton assemblages. The quality of the results from chemotaxonomy based on pigment profiles is directly related to the performance achieved in the chromatographic process. HPLC methods described in the literature differ in resolution, sensitivity, and rapidity on the basis of the type of stationary phase and mobile phase used. The objective of this work is to compare the chromatographic performance of a column with porous shell technology particles with a column with totally porous particles, in the separation of phytoplankton pigments by HPLC. To evaluate the efficiency of the chromatographic column, analyses were carried out using a mixed standard containing 26 pigments and revealed greater resolution and peak shape than those obtained with a column made up of totally porous particles. The efficiency of a column with porous shell particles in separating phytopigments was higher than that of a column with totally porous particles, showing greater resolution and symmetry of the chromatographic peaks, especially for the pairs diadinoxanthin/dinoxanthin, divinyl chlorophyll b/chlorophyll b and divinyl chlorophyll a/chlorophyll a. Studies of the reproducibility of the method were carried out using oceanic samples. The resolution of the pair divinyl chlorophyll a/chlorophyll a, an important cyanobacterial marker, was two times higher in the porous shell column, reducing errors in the quantification of important taxonomic markers and securing the success of pigment-based chemotaxonomy.

New polymeric modifiers of electrophoretic systems have been synthesized. These are cationic polyelectrolytes with micellar properties: poly-11-acryloyloxyundecyl-1,4-diazobicyclo[2.2.2]octanium bromide and a chiral copolymer based on acylated quinine and N-(11-acryloyloxydecyl)-N-methylpiperidinium bromide. The electrophoretic capabilities of these polymers have been studied in the separation of model mixtures of steroid hormones and biogenic amines by capillary micellar electrokinetic chromatography and capillary electrochromatography methods. It has been found that the new polyelectrolytes serve as multifunctional modifiers of the bare fused silica capillary wall and background electrolyte, allow for the implementation of various mechanisms of electrophoretic and chromatographic separation, generate an anodic electroosmotic flow, and influence the separation efficiency and selectivity. It was discovered that the copolymer with quinine acting as a chiral label in the composition of two-phase chiral systems promotes the separation of the enantiomers of β-blockers propranolol and carvedilol.

Oxime reactivators are a part of the standard treatment for chemical warfare nerve agent exposure. Evaluating oxime candidates of interest in biological samples requires analytical detection methods, but oximes as a class of compounds have historically been difficult to isolate, detect, and analyze using conventional analytical techniques. Our lab previously developed novel extraction and liquid chromatography-tandem mass spectrometry (LC–MS/MS) methods to detect and quantitate 2-PAM, HI-6, HLö-7, and MMB-4 in human acetylcholinesterase knock-in, mouse carboxylesterase knock-out (KIKO) mouse plasma. These methods were validated to meet the Food and Drug Administration bioanalytical method validation requirements under Good Laboratory Practice conditions and then were utilized to analyze pharmacokinetic samples from KIKO mice. However, the future utility of these methods has been limited by the lack of reproducibly filled liquid chromatography (LC) columns. Herein we present an alternative LC column for the analysis of these oximes. Previously validated assay methods for oxime extraction from KIKO mouse plasma were evaluated for performance when analyzed by the new LC–MS/MS methodologies. Assays were evaluated for sensitivity, linearity, precision, accuracy, selectivity, and specificity. The results demonstrate that for 2-PAM, HI-6, and HLö-7, there was no change in assay performance when analyzed with the new LC–MS/MS methodologies. However, while MMB-4 was able to be retained on the new column, the sensitivity and linear range were not maintained from the original method. This study evaluates the potential of this alternative column to address inter-lot variability challenges, ensuring the robustness of oxime analytical methods.

Parkinson's disease (PD) causes dopaminergic neuron loss and metabolic and epigenetic abnormalities. DNMT inhibitor decitabine (DB) promotes neuroprotective genes repressed by methylation. Repaglinide (RP), an insulin secretagogue used in T2DM, a PD comorbidity, reduces oxidative stress and inflammation by improving insulin signaling and regulating SIRT1 and HDACs. Bioavailability and half-life are issues for both drugs. Our innovative RP-HPLC technology and solid lipid nanoparticle (SLN) system for dual-drug administration enable prolonged release, brain targeting, and better pharmacokinetics for effective PD treatment. DB and RP were separated using a Waters™ e2695 HPLC system with a PDA detector and a Phenomenex Luna PFP column (250 × 4.6 mm, 5 µm) for enhanced selectivity. A 40:60 isocratic mobile phase (Solvent A:B) was optimized for peak shape and resolution. DB and RP were eluted at 2.7 and 3.6 min, respectively, throughout a 6-min run. The approach enabled precise, consistent, contemporaneous detection of both analytes for high-throughput analysis. Following conventional recommendations, the technique was validated for appropriateness, specificity, linearity, precision, accuracy, and robustness. The validated approach determined 53.26% and 76.68% drug entrapment efficiency in DB and RP SLN formulations. The MTT assay showed that DB and RP preserved N2A cell viability, signifying neuroprotective effects. The results confirmed the method's reliability, making it suitable for other applications, such as the simultaneous detection and quantification of these drugs in liposomal systems, polymer–lipid hybrid nanoparticles, and lipid–drug conjugates for in vitro and in vivo release and entrapment studies.

This study presents the development and optimization of a robust high-performance liquid chromatography (HPLC) method for the separation and detection of vitamin A acetate (VAA) isomers. The analytical strategy is based on stationary phase optimized selectivity liquid chromatography (SOSLC), utilizing a modular reversed-phase (RP) column setup. A range of stationary phases (SPs), including C18 strong hydrophobic (SH), C18 enhanced polar selectivity (EPS), C30, phenyl, and cyano columns were systematically evaluated to construct an optimized composite column with enhanced selectivity. Method development was guided by an existing chiral RP-HPLC gradient method, which served as a conceptual foundation and was adapted into an isocratic format to better accommodate differences in retention behavior and improve robustness. The resulting SOSLC-based HPLC method offers improved selectivity and robustness for the qualitative analysis of VAA isomers, supported by a gentle gradient program to decrease runtimes and sharpen late eluting analyte bands. This approach enables more reliable monitoring of supplement composition and lays the groundwork for future identification and structural elucidation of largely unexplored VAA oxidation products, with initial MS/MS results indicating further potential for analyte characterization.