Chinese Journal of Analytical Chemistry最新文献

Solid-phase extraction (SPE) is an effective method for detecting trace metals. Mg-Al-layered double hydroxide (Mg-Al LDH) materials as an effective adsorbent for SPE because of its large anion exchange capacity, high yield and low cost. A new method was developed for detecting Sb(V) with SPE coupled with inductively coupled plasma mass spectrometry. Mg-Al LDH was synthesized via a simple coprecipitation method and characterized using scanning electron microscopy, Fourier transform infrared spectrometry, X-ray diffractometry, and X-ray photoelectron spectroscopy. Factors affecting the Sb(V) extraction efficiency, such as the eluent type and volume, solution pH, loading flow rate, sample volume, adsorbent weight, and salt concentration, were optimized. Under optimal conditions, the SPE method exhibited good linearity (R² ≥ 0.999) in the range of 0.1–100 μg L⁻¹ with a limit of detection equal to 0.017 μg L⁻¹, good repeatability and reproducibility, and intraday and interday relative standard deviations of 1.84% and 1.48%, respectively. Furthermore, the method was applied to determine traces of antimony in drinking water and bottled water, and findings revealed recoveries between 82.7%–92.1%.

This work investigates the dynamics of supramolecular complexes Calix[n]arenes that are formed by weak forces. These interactions are important for the structure and function of biological molecules and for the design of synthetic host-guest systems. Molecular dynamics simulations are used to explore the reversible binding under of these complexes external force at the atomic level and to complement experimental methods.

The study was carried out to determine the possible bioactive compounds from Ethanol, Methanol, Petroleum ether, and Dichloromethane fractions of Glycosmic cyanocarpa (G. cyanocarpa). Analysis of these extracts was performed using a mass spectrometer detector installed with gas chromatography (GC–MS/MS) utilizing a method named electron impact ionization (EI). The mass spectrum of each extract was compared against the information incorporated in the library (NIST and Wiley) which provides the chemical structure with the name and molecular masses of the identified compounds. A total of 73 compounds (25 from ethanol, 19 from methanol and 5 from dichloromethane (DCM), and 24 from petroleum ether fractions) were identified from various fractions of the plants. Fourier Transform infrared spectroscopy (FTIR) analysis of the crude extracts was done to identify the functional groups of the plant derived compounds. The isolated compounds were subjected to comparison with the standard drugs towards the active binding sites of epidermal growth factor receptor (EGFR) and dihydrofolate reductase (DHFR) proteins for further evaluation of their cytotoxic and antimicrobial activity, respectively. Stigmasterol, beta-Sitosterol, Pyrazol-5-amine, 3-methyl-1,4-diphenyl-, 1,2-Benzenediol,4-(2-aminopropyl)-18,19-Secoyohimban-19-oic acid, and Phenol, 2,4-bis(1,1-dimethylethyl)-, phosphite (3:1) showed maximum binding affinity towards EGFR and 16,17,20,21-tetradehydro-16-(hydroxymethyl)-, methyl ester, (15 beta.,16E)-, Stigmasterol, beta-Sitosterol, Pyrazol-5-amine, 3-methyl-1,4-diphenyl- revealed highest binding affinity towards DHFR receptor. According to the current research, G. cyanocarpa may be a useful natural source for controlling antibacterial and anticancer activity. For thorough phytochemical screening and determining precise mechanisms of action, additional research is required.

In this work, bright blue fluorescent carbon dots (CDs) were synthesized through a hydrothermal method by using l-phenylephrine as carbon source. Under exciting at 363 nm, the prepared CDs emitted bright blue fluorescence at 457 nm. The fabricated CDs showed outstanding salt tolerance, temperature stability and good resistance to photobleaching. Interestingly, the fluorescence of CDs could be distinctly quenched by chlorogenic acid (CGA). By using CDs as fluorescent probe, a novel fluorescence method for highly sensitive detection of CGA was established with a wide linear range of 0.1–220 μM and a limit of detection (LOD) as low as 33 nM. The response mechanism was also studied. The method has been successfully applied for the detection of CGA content in three samples of honeysuckle, coffee beans and Eucommia ulmoides leaves with satisfactory recoveries.

Breast cancer is one of the most common cancers and topmost cause of mortality among women in both developed and developing countries. Currently available potent drugs for breast cancer exhibit adverse effects, which may be caused as a result why breast cancer-specific drugs are found to be ineffective for patients. In this study, we exploited the interaction of six potential drug compounds (Bazedoxifene, Exemestane, Fulvestrant, Raloxifene, Tryprostatin A, and Vorinostat) with three breast cancer associated proteins such as poly (ADP-ribose) polymerase-1; PARP1 (PDB ID: 5HA9) cyclin-dependent kinase 2; CDK2 (PDB ID: 6GUE), and phosphatidylinositol 3-kinases alpha; PI3Kα (PDB ID: 7K6O) using molecular docking studies. Docking results indicate that Raloxifene was shown to be the most potent inhibitor of 5HA9 protein with two hydrogen bond interactions and possesses best binding affinity of −12.3 kcal/mol. The compound Fulvestrant shows three hydrogen bond interactions and has the best binding affinity of −10.2 kcal/mol and exhibits to be the most potent inhibitor of 6GUE protein. Raloxifene indicated best binding affinity of −10.6 kcal/mol and showed to be the most potent inhibitor of 7K6O protein with two hydrogen bond interactions. Molecular dynamics simulations of 5HA9-Raloxifene, 6GUE-Fulvestrant, and 7K6O-Raloxifene were executed for 100 ns through which root mean square deviation (RMSD), root mean square fluctuation (RMSF), the number of hydrogen bonds, radius of gyration, and interaction energy was computed. The obtained results indicate that the compounds Raloxifene, and Fulvestrant can be useful for treatment of breast cancer.

Background

The novel coronavirus disease (COVID-19) outbreak has become a serious global public health crisis, particularly the newly emerged Omicron variant. Although most of the clinical symptoms of Omicron infection are mild, it spreads rapidly and the physiological changes associated with this variant are difficult to understand. This study investigates the possibility of treating renal metabolism in patients with COVID-19.

Methods

High-resolution mass spectrometry was used to detect non-targeted metabolomes in patients with COVID-19 (n = 8) and healthy subjects (n = 12). The main inclusion criteria were that the recovered omicron patients diagnosed as negative, met the discharge criteria and provided information consents. In this study, univariate and multivariate statistical methods were used to analyze the data between the two groups to screen different urinary metabolites associated with Omicron infection. Altered metabolic pathways related to omicron infection were also identified by examining the Kyoto Encyclopedia of Genes and Genomes database.

Results

The single-factor and multi-factor statistics showed that the changes in renal metabolism after treatment were significantly different from those in the control group. Approximately 3500 urinary metabolites were detected in patients recovered of the omicron variant of COVID-19 through bioinformatics methods with 296 metabolites in high confidence level. Different urinary metabolomes were also analysed to inform signal transduction pathways and prognosis prediction; some of these differential metabolites have important biological roles. Compared with the control group, the patients recovered of the omicron variant of COVID-19 exhibited dramatic changes in renal metabolism, including amino acid metabolism, ketone bodies and prolactin metabolic pathways.

Conclusions

Patients with the omicron variant of COVID-19 may have metabolic abnormalities in their urinary system during infection and treatment; thus, follow-up and observation should be strengthened. Thus, this study can provide a certain reference basis for further exploring the pathogenic mechanism and the metabolic indicators of COVID-19.

High-field asymmetric waveform ion mobility spectrometry (FAIMS) enables precise identification of substances through fingerprint spectra obtained by multi-cycle scans at different separation voltages (DV) and nonlinear functions. To improve the scan speed of compensating voltage (CV) in multi-cycle scanning, the challenge arises in peak position shifts. This article proposes a method to accurately determine peak positions regardless of scan speed by exploiting the symmetric features of spectra obtained through positive and negative CV scans. The proposed method enables extremely fast scan speeds. A custom-built FAIMS system was used to verify the correlation between peak shifts and scan speed, the symmetry of spectra peaks under positive and negative CV scan modes, and the peak positions and solution errors of nonlinear functions by using benzene, styrene, acetone, toluene, m-xylene, and hydrogen sulfide as experimental samples. The results demonstrate the widespread occurrence of peak shifts, with peak deviations reaching as high as 2.49% even in slow scans of 0.75 V/s. As scan speed increases, peak position deviations gradually increase, with the maximum deviation reaching 46.83% at a scan speed of 30 V/s. By applying the proposed averaging method, peak positions of the six substances were obtained within the scan speed range of 30 to 0.75 V/s. Compared to traditional methods, the maximum peak position error using the averaging method was reduced by approximately 87.5%, and the spectrum acquisition time was reduced by 85%. The use of the averaging method reduced the calculation error of the alpha function by 88% and decreased the acquisition time by 80%. The research findings of this study offer a solution for the accurate determination of peak positions in FAIMS under fast scanning.

The preparation technology of Dushen decoction solid dispersion (SD) was determined by analyzing the preparation method, carrier type, and carrier ratio. The quality evaluation method was established by infrared analysis spectrometry and differential scanning calorimetry. By using poloxamer 188 as the carrier material and a 1:8 optimal loading ratio, the Dushen decoction SD prepared by the melting method had a better dissolution, and the preparation process was reproducible. The Dushen decoction SD was also highly uniformly dispersed in the carrier material (poloxamer 188), and the mixing mode of Dushen decoction and poloxamer 188 was physical rather than chemical. The dissolution rate of the Dushen decoction SD was nearly 16 times higher than that in the traditional dosage form of Dushen decoction. Therefore, by preparing new formulations of Dushen decoction and establishing quality evaluation methods, a scientific basis can be obtained for follow-up in vivo and preclinical investigation.

Gadolinium (Gd) nanoparticles (NPs) are increasingly considered as a viable alternative to clinically employed Gd chelates in magnetic resonance imaging (MRI). The utilisation of these materials as contrast agents offers several advantages including lower toxicity, prolonged circulation time, and a sufficiently high Gd content, thereby enhancing disease imaging during MRI diagnosis. Therefore, this study synthesised Gd NPs using the hydrothermal method based on the response surface methodology Box-Behnken design (RSM-BBD) to determine the optimal conditions. In this experimental design, three independent variables, the mass of Gd₂O₃ (g), the synthesis temperature (°C) and time (h), were optimised to obtain sufficiently sized nanoparticles for further biomedical applications. In addition, polyethene glycol-6000 (PEG-6000) was used as a stabiliser to form uniformly sized nanoparticles. The optimal conditions were 0.4910 g of Gd₂O₃, a temperature of 180 °C, and a synthesis time of 7 h. Characterisation by scanning electron microscope-energy dispersive X-ray (SEM-EDX) and transmission electron microscope (TEM) demonstrated that the Gd NPs were spherical with a size range below 20 nm. Fourier transform infrared (FTIR) spectroscopy identified PEG molecules with low intensity on the Gd NPs and the obtained zeta potential value was +36.7±0.802 mV. The RSM-BBD analysis applied in this study facilitated the determination of the optimal synthesis conditions.

Activatable phototheranostic probes may become novel option for tumor diagnosis and treatment due to their abilities to accurately detect cancer and guide therapeutic intervention through imaging. In this study, a hyaluronidase (HAase)-responsive near-infrared phototheranostic probe (HA-ICG-PDA) has been developed by covalently coating indocyanine green (ICG)-decorated hyaluronic acid (HA) onto the surface of polydopamine (PDA) for the imaging and therapy of triple negative breast cancer (TNBC). The probe exhibits sensitive and selective fluorescence enhancement to HAase, enabling the detection of HAase and activatable near-infrared fluorescence imaging of HAase-overexpressed tumor cells. Moreover, the combination of ICG and PDA equips HA-ICG-PDA with outstanding photodynamic and enhanced photothermal effects upon 808 nm laser irradiation. Both in vitro and in vivo experiments have confirmed that HA-ICG-PDA is capable of realizing imaging diagnosis of TNBC through HAase-activated fluorescence signal. With the guidance of fluorescence imaging, the probe displays synergistic photothermal and photodynamic therapy effects against TNBC, with minimal damage to the normal tissues. Therefore, the proposed phototheranostic probe paves a new avenue for HAase detection, and subsequently, diagnosis and imaging-guided treatment of TNBC.