Chinese Journal of Analytical Chemistry最新文献

Using terephthalic acid (BDC) as the organic ligand and zirconium chloride (ZrCl₄) as the metal source, a lanthanide metal-organic framework (Tb/Zr-UiO-66) with excellent luminescence properties was successfully prepared by introducing the lanthanide ion Tb³⁺ in situ through a simple one-pot hydrothermal reaction, which was designed as an optical biosensor for 2-thiothiazolidine-4-carboxylic acid (TTCA), the urinary biomarker of human exposure to carbon disulfide (CS₂). The fabricated Tb/Zr-UiO-66 exhibits high chemical and luminescent stability, making it competent for recognizing TTCA in aqueous environments. Significantly, its luminescence intensity change shows a good linearity relationship with the concentration of TTCA in the range of 0–110 μM, with a limit of detection (LOD) as low as 0.14 μM. Meanwhile, this sensor exhibits good selectivity and anti-interference ability towards TTCA among the various coexisting components in urine (Na⁺, K⁺, NH₄⁺, SO₄²⁻, Cl ⁻, creatine, creatinine, glucose, urea, etc.), and can quickly respond to TTCA within 2 min. The analysis results of powder X-ray diffraction (PXRD), fluorescence lifetime and ultraviolet–visible (UV–vis) spectrum demonstrate that the sensing mechanism can be ascribed to the competition absorption effect between TCAA and Tb/Zr-UiO-66. This biosensor with simple synthesis, stable framework, high sensitivity and selectivity, and rapid response has potential to become a powerful tool for diagnosing diseases associated with CS₂ exposure.

Microplastics (MPs) in the atmosphere have attracted global concern due to their potential threats to human health. However, the current rapid analytical method for airborne MPs is insufficient, which hinders a comprehensive understanding of their environmental risks. In recent years, the disposable face masks have emerged as a new source of airborne MPs. There are significant knowledge gaps regarding MPs from mask, including detection methods, formation mechanisms, and environmental abundance. This study presented a novel analytical approach for the rapid detection of airborne MPs using the electromagnetic heating-pyrolysis-mass spectrometry (Eh-Py-MS). To validate this method, surgical face masks were employed as an illustrative example. The mass-related quantification of MPs was realized based on the Eh-Py-MS. By employing a conversion model of mass, size, and density, simultaneous assessment of both mass and quantity of MPs was realized. The recovery rates were in the range of 86.6%–111.6% and the precision (RSD) was 8.4%, which was sufficient for rapid quantification. Results showed that the simultaneous tracing of mass and quantity of airborne microplastics could be successfully achieved through the developed method. Furthermore, the formation mechanism of MPs in surgical masks under UV exposure was also investigated to address the knowledge gap of masks MPs. Results indicated that surgical masks could be a neglected source of airborne microplastics in the environment. This study aims to provide valuable insights for the rapid assessment of airborne MPs in the environment.

Developing an effective method for monitoring of tetracycline (TC) concentrations is extremely crucial due to its adverse effects on both ecosystems and human health. In this study, we developed a novel glutathione-protected nickel nanoclusters (GSHNiNCs) fluorescent (FL) sensing platform to detect TC. The GSHNi NCs were synthesized by a facile one-pot route with GSH as a stabilizer and ascorbic acid (AA) as reducing agent. The experimental results confirmed that the FL of GSHNiNCs was quenched in the presence of TC based on both of the inner-filter effect (IFE) and photoinduced electron transfer (PET) mechanisms to achieve high sensitivity. Under the optimal conditions, excellent linear relationships existed between the FL intensities of GSHNiNCs and the logarithmic TC concentrations in the range of 0.5–120.0 and 120.0–300.0 μM. Even in the absence of surface modification or any complex signal amplification techniques, the proposed FL sensing platform for TC detection showed a low limit of detection of 58 nM (3σ/k). Thus, this approach provides considerable simplicity, low-cost, timesaving and flexibility for the construction of a TC sensor. Most remarkably, we could selectively analyze TC in milk samples without the need for tedious or time-consuming pretreatment processes. This work expands the FL analysis platform for TC detection, and facilitates the design and development of NiNC-based FL sensors for the monitoring of antibiotics.

Chirality, also known as handedness, is one of the most widespread and intriguing properties in nature, touching upon various fields including physics, chemistry, biology, medicine and beyond. Chiral interface is the place where chirality related process occurs. The development of synthetic chiral interface not only deepens the understanding of chiral mechanism, but also provides the basis for the application of chiral phenomenon. In this review, we provide a summary of the various types of chiral interfaces, their construction methods, and the recent process of their application in chiral recognition, chiral separation, and chiral catalysis, as well as a prospect for further direction.

Wastewater contaminated with antibiotics requires innovative solutions to remove such pollutants efficiently. In this work, Zn-Al layered double hydroxide (LDH) adsorbent supported on polyurethane (PU) (Zn-Al LDH/PU) was synthesized using a simple co-precipitation method. The synthesized material was characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), zeta potential, and hydrodynamic size. This adsorbent was investigated for the removal of cefixime (CFX), which is a model third-generation cephalosporin antibiotic. The LDH phase showed a typical hexagonal layered morphology with layer sizes larger than 200 nm in diameter. CFX adsorption on PU, Zn-Al LDH and Zn-Al LDH/PU showed a maximum adsorption capacity of 94.43, 57.17, and 115.69 mg/g, respectively. The Redlich-Peterson and Baudu isotherm models were found to be the best fit models for CFX adsorption of Zn-Al LDH and Zn-Al/PU, respectively. The equilibrium time was found to be 175 and 250 min for CFX adsorption of Zn-Al LDH and Zn-Al/PU, respectively. CFX adsorption kinetics on Zn-Al LDH/PU best fitted the pseudo-second order model indicating chemisorption and diffusion limited adsorption process. Numerous types of bonding between functional groups of CFX and both Zn-Al LDH and PU could explain the adsorption mechanism. The selectivity study of CFX adsorption on Zn-Al LDH/PU using Sulfamethoxazole and Ciprofloxacin with different concentrations was investigated and discussed. The recyclability of this Zn-Al LDH/PU was also studied. Also, the effect of temperature was investigated at (23, 35, 45, 55 °C) and the thermodynamic parameters (∆H°, ∆S° and ∆G°) were calculated showing exothermic and spontaneous adsorption process.The methyl thiazolyl tetrazolium (MTT) assay indicated that the biocompatibility of Zn-Al LDH nanostructures was enhanced following modification with PU, demonstrating regulated and minimal cytotoxic effects towards normal liver cell line (WRL-68). The Zn-Al LDH/PU can be considered as a promising low-cost adsorbent for CFX antibiotic from wastewater streams.

In this work, silver-carbon composite semitransparent hollow spheres (Ag/HCSs) have been successfully synthesized via hydrothermal carbonization (HTC) with trioctylamine (TOA) as a stabilizer and soft template. Furthermore, silver-carbon composites with core-shell structure (Ag@CSs) and carbon films loaded with silver nanoparticles composites with lamellar structure (Ag/CFs) were prepared by adjusting the amount of TOA. The Ag/HCSs were composed of a matrix of ultrathin translucent hydrothermal hollow carbon microspheres with Ag nanoclusters embedded, and numbers of Ag@CSs inside and outside of the hollow carbon microspheres. We further investigated the growth mechanism and morphology evolution, on the basis of the properties of Ag and HCSs, explored the application of the Ag/HCSs for surface-enhanced Raman scattering (SERS). SERS activity was investigated using Rhodamine 6 G (R6G) and crystal violet (CV) as the SERS probe molecules. Ag/HCSs exhibit the best SERS performance among three products. The semitranslucent carbon shell, localized surface plasmon resonances of AgNPs and the effect of charge transfer arising from oxygen-containing moieties make the Ag/HCSs to exhibit good SERS performance, which may give a little inspiration to prepare novel SERS substrates.

In this study, a new technique was developed which combines magnetic solid phase extraction (MSPE) and gas chromatography-mass spectrometer (GC–MS), for the analysis of 17 phthalate esters (PAEs). First, a composite of iron (used as the magnetic part) and graphene oxide (GO) was synthesized for application in MSPE. Scanning electron microscop, X-ray diffraction and infrared spectroscopy were used to characterize this material. Finally, magnetic graphene oxide (Fe₃O₄@GO) was used to extract PAEs from water samples. Various parameters relevant to the extraction were optimized, such as the amount of adsorbent employed, adsorption time, luent solvent types and volume, and sample pH. These optimum conditions resulted in calibration curves for the 17 PAEs, showing linear relationships between concentration and response at concentrations of 25 to 2500 µg L⁻¹ with correlation coefficients from 0.9983 to 1.000. Limit of detection and limit of quantitationfor the PAEs ranged from 0.030 to 0.12 µg L⁻¹ and 0.10–0.40 µg L⁻¹, respectively. The recovery rates for these compounds in spiked samples were ranging from 81.5% to 109% with relative standard deviation less than 6.12%. The effectiveness of method was further demonstrated by its use in detecting 17 PAEs in samples of drinking and bottled water. Compounds such as DEP, DIBP, DBP, and DCHP were identified. These results thus highlight the suitability of Fe₃O₄@GO as an adsorbent for concentrating and purifying PAEs in water samples.

Rapid and nondestructive prediction of component content is the key to improve industrial production efficiency. However, limited data sets also result in low generalization capabilities of the model, and it is time-consuming to obtain a large amount of content reference values and costly. Here, near infrared (NIR) spectroscopy technique combined with deep convolutional generated countermeasure network (DCGAN) was used to predict the trinitrotoluene (TNT) content of the melt-cast explosive. DCGAN was used to simultaneously extend its spectral data and content data. After several iterations, fake data were produced, which was very similar to the experimental data. The partial least squares (PLS) regression model was established and the performance was compared before and after data enhancement. The results showed that this method not only improved the performance of regression model, but also solved the problem of requiring large number of training data.

Tao-He-Cheng-Qi granule (THCQ) was derived from Tao-He-Cheng-Qi Decoction, which has been proved to be one of the effective traditional Chinese medicines (TCMs) applied in the treatment of Intracerebral Hemorrhage (ICH). The objective of this investigation was to study the quality control of THCQ and explore its potential mechanism in treating ICH. According to the results, 20 batches of THCQ had similar chromatographic fingerprints. The similarities of chromatograms of the 20 batches were 0.937–0.998 and 15 major chromatographic peaks were identified as the common peaks for the quality control of THCQ. Subsequently, four analytical methods were successfully established to determine 7 index components of THCQ, respectively, which then were applied in 20 batches of THCQ to determine the content of these index components. Besides, animal experiments were conducted to explore the mechanism of THCQ in the treatment of ICH. After a three-day treatment, behavioral changes and brain histopathological evaluations of SD rats showed that THCQ dose-dependently improved the symptoms of rats with ICH. The results of immunohistochemical evaluations showed that THCQ reduced the expressions of TNF-α and IL-1β. The results of protein expressions detected by ELISA revealed that THCQ dose-dependently reduced Notch1 level and increased the expression of VEGFR. Collectively, the mechanisms of THCQ for treating ICH might be closely relevant to the downregulation of Notch and NF-κB and the upregulation of VEGFR. These findings provided insight for studies in investigating the quality control and further clinical application of THCQ.

An outstanding fluorescent probe for adenosine 5′-triphosphate (ATP) in the millimolar range will shed deep light on the physiological role of ATP. Many fluorescentprobes based on rhodamine spirolactam derivatives have been developed for this purpose and claimed to detect millimolar ATP excellently, where ATP or adenosine 5′-triphosphate disodium salt (ATP-2Na) is employed to examine their response to ATP. However, in this work, it was found that both millimolar ATP and ATP-2Na could significantly decrease the pH of the common buffer solution even for several units. Considering the dependence of the rhodamine spirolactam fluorescence on pH, a series of rhodamine spirolactam-based probes was synthesized to investigate their fluorescence response to pH and ATP-2Na. The results demonstrated that the fluorescence response of the probes to millimolar ATP-2Na indeed resulted from both ATP-2Na itself and the pH decrease induced by ATP-2Na. Furthermore, it was evidenced that acidic pH was crucial for the probes to produce fluorescence response to millimolar ATP-2Na itself, and the rhodamine spirolactam-based probes would show poor sensitivity to millimolar ATP-2Na at near-natural pH. Accordingly, the previous conclusion that the rhodamine spirolactam-based probes could detect millimolar ATP excellently was almost erroneous, and might mislead the design and practice of intracellular ATP probe in the future. This work notes that attention should be paid to the physiochemical properties of the analyte and the environmental changes produced by the target analyte.