Chinese Journal of Analytical Chemistry最新文献

For this research, we performed a 2D-QSAR analysis on a set of 34 molecules derived from dimedone with inhibitory activity against human colon cancer (HT-29). The investigation incorporated principal component analysis (PCA), multiple linear regression (MLR), multiple non-linear regression (MNLR), and artificial neural network (ANN). The evaluations of the QSAR models demonstrated high predictive power (R²_MLR = 0.884; R²_CV (MLR) = 0.86), (R²_MNLR = 0.810; R²_CV (MNLR) = 0.879), and (R²_ANN = 0.9; R²_CV (ANN) = 0.89). The reliability of the models was validated through internal, external, Y-randomization, and validation domain applicability assessments. Utilizing the QSAR model predictions, we designed four new molecular structures that exhibited superior inhibitory activity against the HT-29 human colon cancer cell line compared to the 34 previously tested compounds. Subsequently, we examined the ADMET predictions, Molinspiration, and Osiris properties of the four compounds. The results revealed excellent ADMET predictions and Molinspiration for all four compounds, while only one designed compound fulfilled all Osiris properties. Molecular docking was employed to investigate the bindings between the newly designed molecule C and the c-Met protein. The findings indicated that the newly designed compound exhibited high stability in c-Met. Finally, MD simulations were employed to assess the stability and binding modes of compound C. Based on the MD results, compound C shows promise as a potential c-Met agonist candidate. Overall, our results suggest that this investigated compound has the potential to serve as a novel inhibitor against human colon cancer.

Auxin (mainly indole-3-acetic acid, IAA) is one of the most essential phytohormones with various roles for land plants at different evolution stages and its polar transportation in plants suggested the importance of obtaining its amounts in different plant tissues. Because Marchantia polymorpha is at the entry evolution level, the IAA contents in its tissues would be useful for the study of IAA evolution. Although electrochemical detection offers a possible method for the measurement of IAA amounts, the cost for fabrication of electrochemical sensors is still high given the amounts of IAA tests in the future. Herein a low-cost disposable electrochemical analytical platform was constructed for analysis of IAA in tiny plant samples. Specifically, disposable carbon electrodes were prepared by modifying stainless steel wire mesh with inexpensive carbon ink because of less amounts of materials. The electrode was then integrated with a paper-based analytical device to form a disposable and low-cost platform for rapid electrochemical detection of IAA. For the modified electrode, the highest electrochemical responses for IAA could be obtained when the carbon ink was diluted for 3.5 times. The optimized pH value of the buffer solution for testing was 7.0, which is close to the physiological condition. Coupled with sample treatment using zirconium beads, this approach could successfully differentiate IAA in different tissues of Marchantia polymorpha. The obtained results agreed well with previous reports. This study suggested a sustainable electrochemical analytical detection platform for the study of IAA in practical applications.

The artificial nanomaterials with surface modification are promising platform in targeted therapy, but the nanomaterials are easily tracked by the reticuloendothelial system (RES) before reaching the target sites. Here we report a biomimetic camouflage system, macrophage membrane (MM) coated iron-poly(tannic acid) nanoparticels (Fe-PTA NPs) for targeted drug delivery and magnetic resonance imaging (MRI). The MM inherits the surface protein profiles from macrophage (RAW 264.7 cells), which would escape from RES and target the homotypic cells. The anticancer drug doxorubicin (DOX) was loaded into MM-Fe-PTA NPs, and demonstrated pH-responsive release ability. In addition, the MM-Fe-PTA NPs can be used as T₁-weighted MRI contrast agents for targeted MRI. This cell membrane camouflage strategy has great potential and challenge for clinic targeted therapy.

Selective non-catalytic reduction (SNCR) is a proven technique to reduce nitrogen oxide (NO_x) emissions from stationary sources. The process utilizes NH₃ or urea as a reducing agent, which is only effective in a narrow and high temperature range with the maximum NO_x abatement falling with the increase of the O₂ content. In large industrial boilers, the effectiveness of the deNO_x process may be decreased with boiler load variations and excess O₂. This study investigated carbohydrazide as a reagent to improve SNCR performance. NO reduction by carbohydrazide was experimentally investigated in a pilot-scale flow reactor. The effect of reaction temperature, molar ratio of NH₂ to NO (normalized stoichiometric ratio, NSR) on the NO reduction was determined. Moreover, the promotion effect of carbohydrazide on the reactivity of NH₃ and urea was also investigated. The experimental results indicated that NO reduction by carbohydrazide occurred in a relatively low temperature range of 650–850 °C, and the optimum reaction temperature was about 730 °C at NSR of 2.0, the O₂ content of 11.5%–16.6% and the initial NO_x concentration of 635 mg/m³. After adding a small amount of carbohydrazide to an NH₃ or urea solution, the data showed that carbohydrazide could shift the temperature window of NH₃ to the left, but had no positive effect on urea deNO_x and the NO conversion efficiencies of NH₃ deNO_x. Consequently, carbohydrazide is a potential reducing agent for NO_x, but was not adapted to improve the deNO_x performance with NH₃ and urea.

In this work, a self-assembly approach is proposed to bio-functionalize the fully packaged microfluidic biosensors for catalyzing glucose based on the designed and fabricated microfluidic chip with suspending structure by micro-electro-mechanical system technology. Glucose oxidase is successfully immobilized on the surface of microelectrodes to build composite layers by the proposed self-assembly approach, with cysteamine applied as a functional linker. The biological activity and stability of glucose oxidase is optimized by the electrodeposition of chitosan membrane. Experiments results suggest that the fully packaged microfluidic biosensor integrated with self-assembled glucose oxidase can effectively detect the existence of glucose in sample solution. The detection range of glucose concentration is 0–10 mM. With SNR of 3, the detection limit is 51.2 μM and sensitivity is 23.47 ± 1.36 μA·cm⁻²·mM⁻¹ within low concentration range of 0–0.1 mM, while the detection limit is 497 μM and the sensitivity is 10.63 ± 1.28 μA·cm⁻²·mM⁻¹ among high concentration range of 0.1–10 mM. The proposed study provides a straightforward method to construct a microfluidic biosensor, which is promising in miniaturized clinical medical device.

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.