Analytical Methods最新文献

To ensure the effectiveness of traditional Chinese medicine (TCM) and drive the advancement of high-quality Chinese medicine, the establishment of a scientifically sound quality evaluation system is particularly important. The objective of this study was to develop a straightforward and practical comprehensive evaluation method for quality control of Xiaohuoluo Pills (XHLP) by employing diverse fingerprint technologies. Firstly, Fourier transform infrared spectroscopy fingerprint (FT-IRFP), ultraviolet spectral fingerprint (UVFP) and fusion fingerprints based on five-wavelength matched average fusion fingerprint (FWFFP) were established for 21 samples. Secondly, the Comprehensive Quantified Ratio Fingerprinting Method (CQRFM) was used to conduct a comprehensive evaluation of the fingerprint profiles of 21 batches of samples and the results showed that all samples met the quality requirements. Then to further evaluate the samples, the External Standard Method (ESM) was employed to measure the content of three indicator components in XHLP, and this was done with the intention of enhancing the quality control system of the samples. Furthermore, antioxidant activity was also measured, and a model for analyzing the relationship between antioxidant data and fingerprint information from the three spectra was established using Orthogonal Projection to Latent Structures (OPLS), resulting in an accurate spectral efficacy relationship diagram. In conclusion, this study utilized spectral and chromatography techniques to comprehensively assess the quality of XHLP, incorporating qualitative and quantitative aspects. Additionally, a correlation between spectral profiles and efficacy was established by evaluating the antioxidant capacity of the samples. This method offers valuable insights for quality control not only of XHLP but also for other TCM.

A simple turn-off fluorescent probe, 5-(diethylamino)-2-(hydrazonomethyl)phenol (DHP), is designed and synthesized for the sensitive and selective detection of Cu²⁺. The bright green fluorescence of DHP is quenched after the addition of Cu²⁺. The probe DHP exhibits good anti-interference performance against Cu²⁺ in the presence of multiple metal ions. The fluorescence intensity of DHP (10 μM) at 522 nm is well linearized with the Cu²⁺ concentration at 0-5 μM, and it has a detection limit of 0.29 nM (R² = 0.9949). The complexation ratio of the probe DHP to Cu²⁺ is 2 : 1 and the complexation constant is 3.44 × 10⁴ M^-1 (R² = 0.9974). In addition, the probe DHP can be recovered using EDTA and Cu²⁺ can be effectively monitored at pH 5-11, with good results in dipstick experiments and actual water samples. HepG-2 cells remained viable in excess of 90% after being exposed to DHP (50 μM) for 24 h, which demonstrates the extremely low toxicity of DHP, and it can be used for in vivo cell imaging.

Covalent organic frameworks (COFs) can be rationally designed with functional organic ligands to improve the electrochemical responsiveness of the electrode toward certain medicinal compounds. In this study, we synthesized a COF-Ni electrocatalyst material, which is formed by covalent coupling of electron-rich 2,3,6,7-tetrakis (4-formylphenyl) tetrakis (4-imidazolyl) (TTF-4CHO) and hole-rich 5,10,15,20-tetrakis (4-aminophenyl) porphyrin nickel(II) (TAPP-Ni). The reasonable electron transfer path design, the large specific surface area of the COF and the physical properties of ordered nanopores, as well as the Ni–N₄ bond as a highly active catalytic center, allow the COF-Ni material modified electrode to exhibit excellent sensing performance for acetaminophen (ACOP). The detection limit for ACOP is as low as 47.6 nM, with a linear range of 1–1500 μM, which is better than for most of the reported sensors. With superior interference resistance and good stability performance, COF-Ni is a highly suited electrode modification material for real-world sample detection, which provided a new perspective for application of COF materials in drug analysis.

In this review, we explore the electroanalytical determination of mycophenolate mofetil and mycophenolic acid. Mycophenolate mofetil is a prodrug of mycophenolic acid, which is an immunosuppressive agent used to lower the body's natural immunity in patients who receive organ transplants as well as to treat autoimmune conditions. Laboratory based analytical instrumentation provide a routine methodology to measure mycophenolate mofetil and its metabolites, but there is scope to develop in-the-field analytical measurements that are comparable to those from laboratory equipment. Electroanalysis provides an opportunity to provide highly selective and sensitive outputs but are cost-efficient and can support on-site analysis. In this review, we provide an electroanalytical overview of the current research directed toward the measurement of mycophenolate mofetil and mycophenolic acid, offering insights to future research.

In the last few decades, pharmaceuticals have emerged as a new class of serious environmental pollutants. The presence of these emerging contaminants even in minimal amounts (micro- to nanograms) has side effects, and they can cause chronic toxicity to health and the environment. Furthermore, the presence of pharmaceutical contaminants in water resources leads to significant antibiotic resistance in bacteria. Hence, the removal of antibiotics from water resources is essential. Thus far, a wide range of methods, including adsorption, photodegradation, oxidation, photolysis, micro-/nanofiltration, and reverse osmosis, has been used to remove pharmaceutical contaminants from water systems. In this article, research related to the processes for the removal of metronidazole antibiotics from water and wastewater, including adsorption (carbon nanotubes (CNTs), magnetic nanocomposites, magnetic molecularly imprinted polymer (MMIP), and metal–organic frameworks), filtration, advanced oxidation processes (photocatalytic process, electrochemical advanced oxidation processes, sonolysis and sonocatalysis) and aqueous two-phase systems (ATPSs), was reviewed. Results reveal that advanced oxidation processes, especially photocatalytic and sonolysis processes, have high potential in removing MNZ (more than 90%).

Accurately quantifying hydrogen peroxide (H₂O₂) is essential for elucidating its role across diverse environments. Spectrophotometry is widely employed in laboratories for this purpose due to its convenience, cost-effectiveness, and low detection limits for micromolar H₂O₂ concentrations. However, accurate measurement of H₂O₂ in iron-containing solutions presents challenges due to the interference of iron ions. In this study, we propose a modified spectrophotometric method for H₂O₂ determination in iron-containing solutions by adding two types of iron ion chelators and selecting leuco crystal violet (LCV) as a chromogenic reagent due to its stability. By sequentially adding 1,10-phenanthroline and EDTA, and using a phosphate buffer at pH 4.2 to provide the optimal chromogenic pH condition, this modified method effectively mitigates the interference of iron ions in the LCV chromogenic reaction. The applicability of this method under aerobic and anaerobic conditions was confirmed by comparing the experimental results with theoretical simulations. Under optimal chromogenic conditions, this method achieves a detection limit of 300 nM. This improved method allows better detection of H₂O₂ in iron-containing systems and investigation of its significance in various environmental processes.

A review with 93 references describing various 3D printing approaches that have been used to create microfluidic devices containing electrodes for electrochemical detection. The use of 3D printing to fabricate microfluidic devices is a rapidly growing area. One significant research area is how to detect analytes in the devices for quantitation purposes. This review article is focused on methods used to integrate electrodes into the devices for electrochemical detection. The review is organized in terms of the methodology for integrating the electrode within the device. This includes (1) external coupling of traditional electrode materials with 3D printed devices; (2) printing conductive electrode materials as part of device printing; and (3) integrating traditional electrodes into the device as part of the print process. Example applications are given and some future directions are also outlined.

A retention time (RT)-independent strategy for nontargeted screening of pesticide residues in herbs was exploited using liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF MS). The core of this strategy is a fingerprint database coupled with a data-independent acquisition (DIA) scan mode of all ion fragmentation (AIF). In the fingerprint database, a total of 150 pesticides with quasimolecular ions and fragment ions at five-level collision energies were collected as qualified ions for screening. During the data acquisition, the AIF scan was performed via real unbiased full-spectrum MS/MS acquisition. Six herb matrices spiked with 30 banned pesticides were used to evaluate the applicability of the strategy in real samples. The use of the narrow ion mass extraction window (10 mDa) and the narrow RT window (0.1 min) enabled the effective extraction of spectra from noisy backgrounds and the discovery of suspected pesticides via similarity matching of filtered qualified ions. On average, more than 11/30 of pesticides at 1 ng mL⁻¹ and more than 23/30 of pesticides at 10 ng mL⁻¹ or lower could be screened out in each matrix using at least two qualified ions. In addition, the AIF mode exhibited superior anti-interference capability compared to data-dependent acquisition (DDA) and sequential window acquisition of all theoretical mass spectra (SWATH), as determined by comparing the limits of screening (LOSs) of 30 banned pesticides spiked into Isatidis Folium. Finally, the developed strategy was applied to screen pesticide residues in extracts of Ganoderma and Foeniculi Fructus. Phorate-sulfone and phorate-sulfoxide were found in Ganoderma, as well as terbufos-sulfone and terbufos-sulfoxide were found in Foeniculi Fructus. In conclusion, the developed RT-independent strategy based on a fingerprint database and AIF acquisition with LC-QTOF MS seems to be one of the most efficient tools for the analysis of nontargeted pesticide residues in complicated matrices.

Gas chromatography-ion mobility spectrometry (GC-IMS) is an advanced technique used for detecting trace compounds, due to its non-destructive, straightforward, and rapid analytical capabilities. However, the application of GC-IMS in human disease screening is barely reported. This review summarizes the application and related parameters of GC-IMS in human disease diagnosis. GC-IMS detects volatile organic compounds in human breath, feces, urine, bile, etc. It can be applied to diagnose diseases, such as respiratory diseases, cancer, enteropathy, Alzheimer's disease, bacterial infection, and metabolic diseases. Several potential disease markers have been identified by GC-IMS, including ethanal (COVID-19), 2-heptanone (lung cancer) and 3-pentanone (pulmonary cryptococcosis). In conclusion, GC-IMS offers a non-invasive approach to monitor and diagnose human diseases with broad applications.

Cotton fabric was used as a substrate for smartphone-based image analysis of Cu(II) in drinking water. To enhance its selective and specific binding sites on the cotton surface, a molecularly imprinted polymer (MIP) was introduced using color complexes of 4-(2-pyridylazo)resorcinol–Cu(II) (PAR–Cu(II)) as the template molecule, 3-aminopropyltriethoxysilane (APTES) as the functional monomer, tetraethoxysilane (TEOS) as the crosslinker and NH₃ as the catalyst. After achieving optimum conditions, the obtained CF-MIP/PAR–Cu(II) presented a red color, which was changed to yellow upon the removal of Cu(II) with 1.5 M HCl. After using CF-MIP/PAR to detect Cu(II), the red, green and blue intensities of the images captured using a smartphone were analyzed using the ImageJ program. For the calibration curve plotted between Δgreen intensity and Cu concentration, the linear range was 0.10–1.0 mg L⁻¹ with the best correlation coefficient (R²) of 0.999. The limit of detection (LOD) and the limit of quantification (LOQ) were found to be 0.038 and 0.11 mg L⁻¹, respectively. To obtain a distance-based device, MIP-modified cotton thread (CT-MIP/PAR) with a four-channel design was used as an alternative device. The distance of red color development was measured after using CT-MIP/PAR to detect Cu(II). The linear range was 0.50–3.0 mg L⁻¹ with an R² of 0.997. The LOD and LOQ were 0.18 and 0.56 mg L⁻¹, respectively. The proposed methods provide simple, portable and inexpensive devices with high accuracy and precision for the detection of Cu(II) in drinking water.