Journal of Analytical Methods in Chemistry最新文献

The diverse industrial use of chlorinated paraffins (CPs) have led to their environmental dispersion, and special attention has been paid to their ecotoxicology. Among them, short-chain chlorinated paraffins (SCCPs) have been listed as potential persistent organic pollutants (POPs). However, currently, technical CPs produced by manufacturers are usually labeled by their chlorination degree, but such structural label is not enough to reflect CPs' environmental fate and toxicity. Ecotoxicology research suggested that the chain length, chlorination degree and the chlorine distribution pattern are all factors that can determine CPs' environmental fate and toxicity. Herein, we present a cost-effective method for the structure characterization of technical CPs. By using direct injection mass spectrometry with data deconvolution, chain length distribution and homologous distribution in technical CPs mixture can be delineated. By using ¹H NMR with chemometrics tools, the chlorine distribution pattern can be elaborated. Combining the abovementioned two analytical strategies, structural information at different levels that related to CPs' environmental fate and toxicities were revealed. This method is expected to be easily applied in both industry and academia, aiming for quality control of technical CPs, by permitting only nontoxic or noncarcinogenic CPs into industrial use.

Dopamine (DA) is a catecholamine neurotransmitter secreted by the human adrenal medulla and is related to many medical diseases. The rapid and sensitive detection of DA levels in physiological media is attracting attention. This paper has developed a fluorescence paper-based sensor using CdTe quantum dots (QDs)-rod nanozinc 5, 10, 15, 20-tetra (4-pyridyl)-21H-23H-porphine (nanoZnTPyP) for sensitive and visual detection of DA. After adding DA, the original quenching fluorescence of the CdTe QDs-rod nanoZnTPyP sensor was effectively restored. The detection mechanism may be that the oxidation of DA to the alkaline CdTe QDs-rod nanoZnTPyP solution produced DA-quinine, and the recovery of fluorescence was caused by the electronic effect of DA-quinine and rod-shaped nanoZnTPyP. The detection range is 0.5∼10 nmol/L, and the limit of detection (LOD) is 0.38 nmol/L (S/N = 3). The sensor system was used on paper device to detect significant changes in the fluorescent color of DA at different concentrations. In addition, this method has been successfully used for the determination of DA in human plasma. The sensor system is simple, easy to operate, and has high selectivity for possible DA interfering substances, which provided new ideas for detecting DA and Parkinson's disease, Alzheimer's disease, and other DA-related diseases.

Despite the availability of current resources, the development of medical countermeasures remains crucial in combatting the threat posed by chemical warfare agents, such as organophosphorus compounds (OPs), which are toxic nerve agents requiring rapid medical intervention. Within the available therapeutic arsenal, muscarinic antagonists such as atropine are administered to mitigate the effects of excessive cholinergic system stimulation, which leads to respiratory tract obstruction due to hypersecretions and bronchoconstriction. Tiotropium, an FDA-approved bronchodilator, acts as a muscarinic receptor antagonist and could, therefore, serve as a potential alternative. To assess its potential efficacy in attenuating OP-induced respiratory effects in a murine intoxication model, it was necessary to first characterize its pharmacokinetic properties. A liquid chromatography-mass spectrometry method was developed and validated following ICH M10 guidelines for the quantification of atropine and tiotropium in 10 μL of plasma. The sample pretreatment procedure involved solid-phase extraction. Chromatographic separation was achieved using a fully porous sub 2 μm C18 column. The analysis was completed in just 4 min, with analytes identified and quantified using two selected reaction monitoring transitions. The mean extraction recoveries exceeded 90% for both drugs, and no matrix effect was observed. The lower limits of quantification were 0.5 ng/mL for tiotropium and 1.0 ng/mL for atropine, with an upper limit of 1000 ng/mL. The signal-to-concentration ratio demonstrated recoveries of back-calculated concentrations ranging from 94% to 108% (relative standard deviation (RSD) < 9.0%). Within-run and between-run precisions were both below 8% with accuracies ranging from 87% to 110%. This highly specific and sensitive method has proven useful for analyzing samples from pharmacokinetic studies conducted in mice. Following intraperitoneal administration, the AUC for tiotropium was approximately twice that of atropine, while its Tmax was half as long (4.9 vs. 8.2 min). The terminal half-lives were approximately 7.5 min for tiotropium and 9.8 min for atropine.

Objectives: To establish and validate a sensitive and robust gas chromatography-mass spectrometry (GC-MS) method for the quantification of β-elemene in human plasma and assess the correlation between antitumor effect and β-elemene concentration in vivo. Methods: The chromatographic column was HP-5 ms (30 m × 0.25 mm, 0.25 μm, Agilent, United States of America). The carrier gas was helium (purity > 99.5%). The flow rate was 1.0 mL/min and the total run time was 11.0 min. The plasma sample was pretreated with protein precipitation plus liquid-liquid extraction. Cancer patients were enrolled and their samples were collected for analysis. Results: Calibration range of β-elemene was 200.0-20,000.0 ng/mL, with correlation coefficients > 0.99. The intra- and interday precision and accuracy were less than 5.8% and within the range of -10.4%-6.6%. The exposure level of β-elemene in the responder group ranged from 278.13 to 11,886.27 ng/mL, with a median of 3568.91 ng/mL, while in the nonresponder group, the range was from 675.92 to 9716.52 ng/mL, with a median of 3351.94 ng/mL. No difference was found in the β-elemene exposure level between the two groups (p > 0.05). Conclusions: This method was effectively developed, validated, and utilized to quantify β-elemene in cancer patients. The initial findings indicated no significant relationship between therapeutic efficacy and the concentration of β-elemene.

Headspace-gas chromatography-ion migration spectrometry (HS-GC-IMS) combined with chemometrics was used to analyze the changes in volatile aroma compounds (VOCs) at different production stages of steaming Polygonatum cyrtonema Hua. Fifty-seven representative compounds in the process of steaming were identified, including 17 aldehydes, 15 alcohols, 15 ketones, 5 esters, 3 furans, and 2 acids. After steaming, the content of 21 compounds decreased. Among them, 3 compounds gradually decreased along with an increase in steaming times; they were 1-hexanol dimer, 1-hexanol monomer, and 3-methylbutan-1-ol dimer. The content of 14 compounds increased than before, and that of three, 1-(2-furanyl)ethanone monomer, 2-furaldehyde, and 3-methyl butanal, increased significantly in the steaming times. The VOCs of the different samples can be classified by GC-IMS data combined with principal component analysis (PCA) and heatmap cluster analysis. A reliable prediction set was established by orthogonal partial least squares discriminant analysis (OPLS-DA), and 18 different VOCs with projected variable importance (VIP) greater than 1.0 were screened out, which could be used as differentiating markers. Therefore, HS-GC-IMS and PCA were used to rapidly identify and classify the VOCs in different production stages of steaming P. cyrtonema Hua.

Information about sea surface temperature (SST) allows both local and global climate reconstructions dating back centuries to millennia. To determine SST variations over time, including the deep past, a number of proxies are used. Li/Mg, Mg/Ca, Sr/Ca, and U/Ca ratios in coral skeletons are the most commonly used high-resolution temperature proxies. Various methods, using different types of instrumentation, are employed to obtain high-precision data on the variation of these ratios in coral skeletons. Generally, each method has its own advantages and disadvantages; however, a common drawback of most is that they are time-consuming. This article presents a quick, simple, and high-throughput method for determining mentioned ratios in coral skeletons using quadrupole ICP-MS. The reduction of calcium concentration to 3 ppm in the analytical solutions, combined with optimized operating conditions and quasi-simultaneous measurement of each element pair, ensures excellent signal sensitivity and stability of ratio values during sample runs. The drift of ratio values was investigated using the in-house coral secondary standard NEP-3b. During some runs, the drift of ratios during the analysis was so low that it provided excellent repeatability of results without off-line mathematical correction of the obtained data. Due to the selected ICP-MS operating conditions, this high-sensitivity method enables for the analysis of all studied isotopes in a single measurement, whereas typical procedures require two sample preparations and separate measurements. As a result, this method doubles the throughput compared to the previous procedures while demonstrating comparable short- and long-term precisions, both of which were assessed using the international standard sample JCp-1.

Objective: Aconitine alkaloids, as the principal bioactive constituents of Fuzi, pose a significant challenge to its clinical application due to their toxicity. This study aimed to establish a rapid, efficient, and stable method for quantifying monoester-type and diester-type alkaloids in raw Fuzi using zeolitic imidazolate framework-8 (ZIF-8). The method was subsequently applied to pharmacokinetic studies in rats, offering valuable insights into the safe clinical use of Fuzi. Methods: Synthetic ZIF-8 was employed as the microextraction adsorbent, with optimization of extraction parameters such as ZIF-8 content, shaker speed, extraction time, and sodium ion concentration to maximize enrichment efficiency. A dispersive solid-phase extraction-liquid chromatography-tandem mass spectrometry (d-SPE-LC-MS/MS) method, based on ZIF-8, was developed and validated for method performance. The pharmacokinetics of five aconitine alkaloids in Fuzi were investigated, ensuring efficient extraction and analysis. Results: Under the optimized conditions, the d-SPE method demonstrated robust enrichment of aconitine alkaloids. A strong linear relationship was established for aconitine, hypaconitine, mesaconitine, lappaconitine, and benzoylaconitine within the concentration range of 0.3125-1000 ng/mL, with correlation coefficients exceeding 0.99. The LC-MS/MS assay achieved a detection limit as low as 0.104 ng/mL. Additionally, the pharmacokinetic analysis revealed rapid absorption of the five alkaloids, with benzoylaconitine exhibiting a T_max of 0.25 h. Conclusion: This study introduces a novel d-SPE-LC-MS/MS method based on ZIF-8 for the analysis of aconitine alkaloids in plasma, facilitating pharmacokinetic studies of Fuzi. These findings substantially contribute to a deeper understanding of the in vivo pharmacokinetics of aconitine alkaloids.

To fully comprehend each pesticide's behavior and interactions with soil and the environment, a thorough and nuanced analysis of each one is thought necessary. In this study, 10 randomly selected heterogeneous soil samples, each with distinct characteristics, were subjected to sorption trials as well as disintegration tests using biodegradation, hydrolysis, and photolysis. For sorption tests, the batch equilibrium approach was used, which revealed a dependence on the soils' physicochemical characteristics. Bifenthrin's distribution coefficient (K _d ) varied from 7.27 to 25.89 μg·ml^-1, with R ² values varying from 0.92 to 0.99. Each soil physicochemical characteristic was associated with the various sorptive outcomes, which suggested an exothermic adsorptive reaction based on the negative thermodynamic values. The hydrolysis, soil-induced biodegradation, and photolysis processes had the shortest half-lives of bifenthrin, measuring 13.5 days, 12 days, and 121.5 days, respectively. According to these findings, bifenthrin has a moderate amount of binding and stability in soil, which makes partial decomposition of parent and daughter molecules challenging. This research advances our knowledge of bifenthrin's deteriorating processes and aids in the creation of cutting-edge strategies for ecological restoration using natural processes.

Baicalin concentration is concerned in manufacture of scutellaria spray drying powder as a traditional Chinese medicine, and the quality control based on high-performance liquid chromatography is inconvenience. In this study, terahertz time domain spectroscopy was employed to achieve quality control of scutellaria spray drying powder; however, an acute difficulty was found that terahertz spectra overlapped due to the disturbance in both content matrix and measurement error. In this study, similar terahertz spectra of scutellaria spray drying powder were classified with the help of Gaussian mixture model and built a classifier based on probability feature instead of spectral features conventionally employed in previous investigations. To explore the feasibility of GMM, principal component analysis was given, indicating that it is possible to train GMM with original features and proper principal components. Probable advantage of training GMM based on PCA feature was discussed and so it was with the capacity of the model to identify the linear combined spectra by comparing the performance of GMM and a decision tree model. Above all, the reason why GMM shows potential in the analysis of TCM terahertz spectra was illustrated by comparing the thought of discriminative model and generative model. This study implied that generative model may have natural advantage of overcoming the inherent disturbance of terahertz spectroscopy, which would be promising in future studies.

In this study, high-performance liquid chromatography-evaporative light scattering detection (HPLC-ELSD) and HPLC-mass spectrometry (HPLC-MS) were employed for the quantitative analysis of steroidal saponins of Semen Allii Fistulosi. The HPLC-ELSD method was simple, accurate, and repeatable, and the recoveries were 97.91%∼99.77%. Similarly, the HPLC-MS method was rapid, sensitive, accurate, and reproducible, and the recoveries ranging from 95.61% to 99.70% in the control samples. The sensitivity of the HPLC-MS method was several times higher than that of the HPLC-ELSD method. These results collectively demonstrated that these methods are suitable for the content determination of steroidal saponins of Semen Allii Fistulosi and the identification of its plant source.