Chinese Journal of Analytical Chemistry最新文献

In this study, by conducting simulated in vitro digestion experiments on samples, the extraction rates of several essential metal elements in some common food ingredients were determined to guide a rational and balanced diet. At the same time, taking vegetables as an example, the research investigated the impact of food preprocessing on the extraction rates of metal elements within them, demonstrating that the influence of heat treatment varies for different element extraction rates. A wet digestion system using nitric acid-hydrogen peroxide was established for seafood and vegetable samples, and an analytical method for determining Ca, Cu, Fe, Mn and Zn using inductively coupled plasma optical emission spectrometry (ICP-OES) was developed. The detection limits of the method ranged from 0.0003 mg L⁻¹ to 0.1567 mg L⁻¹, with RSDs between 0.004% and 7.161%. The measured contents of several important metal elements in standard substances were largely consistent with national standards, confirming the accuracy and precision of the method. Based on wet digestion, the contents of various metal elements in simulated digestive fluids were determined. The detection limits for the simulated digestion method ranged from 0.0005 mg L⁻¹ to 0.0077 mg L⁻¹, with RSDs between 0.001% and 8.839%, verifying the precision of the method. Consequently, the extraction rates of metal elements in the two types of samples were obtained, leading to the conclusion that vegetable samples are more easily digested compared to seafood, releasing their metal elements. Moreover, the extraction rates of different elements vary within the same type of sample, and the extraction rates of the same element also differ across different samples. For dried fruit samples, a dry ashing digestion system was established, and an analytical method for determining Ca, Cu, Fe, Mn and Zn using ICP was developed. The detection limits of this method ranged from 0.0003 mg L⁻¹ to 0.0073 mg L⁻¹, with RSDs between 0.001% and 1.076%, and the spiked recovery rates were between 85.43% and 105.96%, confirming the accuracy and precision of the method. Based on dry ashing digestion, the contents of various metal elements in simulated digestive fluids were measured, which led to the determination of the element extraction rates. Among these, the extraction rates for Ca, Cu, and Mn were relatively high.

α2-macroglobulin (α2-M) have crucial clinical significance as a potent biomarker for diabetes nephropathy (DN). There is an increasing demand for rapid detection of α2-M. Herein, a magnetoelastic (ME) biosensor with a layered composite structure is developed for α2-M detection. Based on 3D printing, the basal layer of the biosensor is prepared as a grid structure fabricated by polylactic acid (PLA) doped with NiFe₂O₄. The conductivity of the biosensor was improved significantly due to the addition of multi-walled carbon nanotubes (MWCNTs). The biological site for capturing α2-M antigen was provided by the carbon quantum dots (CDs) coupled with anti-α-2M (anti-α2-M@CDs) in the nitrocellulose filter (NC) membrane. Meanwhile, the distribution of antibodies on the biosensor surface can be observed more directly due to the fluorescence characteristics of CDs. The biosensor in this work can realize multi-pattern recognition of fluorescent signal and electromagnetic signal. The results show that the limit of detection (LOD) was 0.506 ng/mL in the linear range from 10 ng/mL to 100 µg/mL and the linear equation of fitting curve is: y = 0.21 x - 0.15. The ME biosensors with a simple preparation method have advantages of high sensitivity, good stability and low LOD, showing the great potential for α2-M detection.

The electrochemical sensor has been considered an efficient and portable platform for the rapid quantification of nitrate ions in industrial wastewater and natural water bodies. Albeit of the high sensitivity to NO₃⁻, the electron-deficient copper sites (Cu^δ+) were unstable under the negative working potentials for detection (Cu^δ+ was readily reduced to Cu⁰). Herein, the Schiff base was grafted on MIL-125 (Ti) via covalent binding to stabilize the Cu^δ+, leading to a composite Cu^δ+/Schiff base/MIL-125 (Ti) material (abbreviated as CuSM) for NO₃⁻ sensing. Moreover, the unique porous structure of CuSM can speed up the diffusion rate of NO₃⁻ from the bulk solution to the surface of the modified electrode, enhancing the sensitivity of NO₃⁻ assay. As a result, the CuSM-based sensor not only exhibited a wide linear range from 1.18 μM to 58.8 mM and a low detection limit (S/N = 3) of 0.253 μM but also possesses high specificity, excellent reproducibility (the RSD of the five inter-batch sensors was 1.138%) and the ability to detect real water samples.

Objective

To investigate the effects of water extract of the spleen-brain-related mineral drug Shehanshi on mouse sleep.

Methods

Shehanshi water extract was subjected to component analysis via X-ray photoelectron spectroscopy. Then, the effects of low-dose (50 mg kg^-1) and high-dose (100 mg kg^-1) Shehanshi water extract on mouse sleep were evaluated through behavioral tests such as pentobarbital sodium subthreshold and above-threshold sleep experiments and autonomic activity experiments. Furthermore, transcriptome sequencing and nontarget metabolomics analysis were performed on the spleen and brain tissues of the mice.

Results

The Shehanshi water extract contains a total of 30 elements and can reduce sleep latency, increase sleep time, and increase the sleep rate of mice. In the open field experiment, the movement distance of the mice decreased, and the central residence time and rest time increased. Immunoinfiltration analysis and immunohistochemical verification of spleen tissue showed that compared with those in the control group, the immune abundance of neutrophils in the administration groups increased (P < 0.05). Transcriptome data analysis revealed that the Atp1b2 gene was located at the intersection of the spleen and brain and was positively correlated with neutrophil expression but negatively correlated with the expression of the metabolite oleic acid in brain tissue. Immunohistochemical results showed that Atp2a3 protein expression decreased and Plcg1 protein expression increased in the high-dose group, and the difference was statistically significant (P < 0.05). The Atp1b2 protein level in the spleen tissue was positively correlated with that in the brain tissue of the mice (R = 0.829, P = 0.038). Western blotting revealed that Atp1b2 protein levels in the brain and spleen increased significantly in the high-dose group (P < 0.05).

Conclusion

The mechanism by which Shehanshi water extract influences sleep may be associated with the expression of genes related to the spleen-brain axis and calcium signaling pathways in brain tissues.

In graph theory, topological indices are numerical metrics that give information about a graph’s structural traits. The face index is one such topological index that describes planar networks. Since the discovery of graphene, the genealogy of two-dimensional 2D crystals has expanded and currently contains a large variety that has all logical electrical properties required for nano electronics. Nanotechnology benefits from the use of materials that resemble Dirac, such as silicon, graphite, semiconductors, and germanene, as well as TMDC (phosporene), a transition metal dichalcogenide. In contrast with standard topological descriptors, which are numerical values utilised to characterise molecular structures, the face index presents a potentially more comprehensive method for obtaining structural details. In investigations involving quantitative structure-property relationships (QSPR), this may result in more precise predictions. We calculated the recently created face index of Germanium Phosphide (GeP) and its many shapes, including triangle, rhombus, hourglass, and concentric circles.

Cigarette smoke contains various harmful substances, including heavy metals, that pose significant health risks. Tobacco smoking is the leading cause of lung cancer, accounting for approximately 90 % of lung cancer-related deaths worldwide. However, limited information is available on the health hazards posed by heavy metals in cigarettes commonly consumed in Tanzania. This study aims to assess the potential health risks associated with heavy metal exposure from eight most commonly consumed cigarette products in Tanzania using atomic absorption spectrometry. The concentrations (mg kg⁻¹) of copper (Cu), zinc (Zn), cadmium (Cd), chromium (Cr), and nickel (Ni) ranged from 6.94 to 16.31, 0.6–1.93, 0.4–0.66, 0.69–2.86, and 0.11–2.69, respectively, with mean concentrations of 9.35, 0.92, 0.52, 1.82, and 1.24 mg kg⁻¹. The mean concentrations of Cu and Zn are within the permissible limits set by FAO/WHO while Cd, Cr, and Ni exceeded these limits, raising concerns. A high positive correlation is observed between Cu and Zn ($r=0.988$, $p=0.01$). The non-carcinogenic hazard quotient (HQ) for ingestion is below 1, indicating minimal risk, whereas HQ for inhalation is above 1, indicating considerable health risk. The carcinogenic risk assessment for ingestion is within acceptable limits for all metals. However, Cd, Cr, and Ni present higher risks than the acceptable limit set by USEPA (1E-06 to 1E-04), suggesting significant cancer risk associated with these metals. This study highlights the need for stringent regulation and monitoring of heavy metal content in cigarettes to mitigate health risks.

Halogenated polycyclic aromatic hydrocarbons (H-PAHs) are the emerging organic pollutants in environment, which are ubiquitous in the atmosphere, soil and water. Some H-PAH congeners have been proven to have dioxin-like toxicity. However, the research on the human internal exposure of H-PAHs is still limited. A simple and efficient analytical method is essential for the study of human internal exposure, so a method for the rapid and simultaneous determination of 16 polycyclic aromatic hydrocarbons (PAHs) and 33 H-PAHs in human serum was established in this study. After 1.0 mL serum was extracted with ethyl acetate/acetonitrile (1:4) solution containing 1 % formic acid, samples were purified by Captiva EMR-Lipid solid phase extraction column, and then determined by gas chromatography tandem triple quadrupole mass spectrometer (GC-MS/MS). The results showed that the recoveries of PAHs and H-PAHs ranged from 71.2 % to 119 % and 68.8 % to 121 %, respectively. When 1.0 mL of serum sample is used, the method detection limit of PAHs and H-PAHs is 0.001–0.314 ng/mL. The method is simple and efficient, and suitable for the simultaneous determination of trace PAHs and H-PAHs in human serum. High concentrations of chlorinated polycyclic aromatic hydrocarbons were detected in pooled serum, of which 1,5-dichloranthracene was the main contributor congener, with a concentration of 204–328 ng/g lipid, which deserved more attention.

In this work, the process of forming PF4/heparin complex was described based on their sizes measured with PCS. PF4/heparin complexes formed when a small amount of heparin was added to PF4, and they grew to bigger particles when more heparin was added, but they started to decompose after a certain amount of heparin was added. The larger the molecular weight of heparin has, the less amount of heparin is required to form the complex with PF4. This process was verified by the results of the complex surface charge. This method was used to compare the immunogenicity among the different batches of nadroparin after its specificity and stability were validated.