Analytical Methods最新文献

As a metallurgical bulk solid waste, stockpiled steel slag risks land occupation, as well as soil and groundwater pollution. Its low-activity T₁-C₃S (Ca₃SiO₅) changes to high-activity M₃-C₃S boosted hydration activity and reduces harmful releases via lattice solidification, thereby meeting environmental and industrial needs. To fit "green" metallurgical processes, we achieved T₁-C₃S-to-M₃-C₃S transformation in steel slag by optimizing cooling parameters and preparing and characterizing pure-phase C₃S and studying cooling-induced crystal forms. Meanwhile, first-principles calculations explored the reactivity-electronic structure relationship of C₃S polymorphs. Results indicated increased cooling rate weakened pure-phase C₃S lattice amplitude, and water cooling at the synthesis temperature led to relatively high T₁-C₃S mass fraction. For steel slag under a specific water-cooling temperature, MgO solid solution effectively promoted the conversion of T₁-C₃S to M₃-C₃S to maximize M₃-C₃S content. Also, rapid cooling accelerated steel slag particle cracking, significantly increased pore parameters, and optimized compatibility with construction material feedstock. We optimized the cooling process to achieve T₁-C₃S-to-M₃-C₃S transformation in steel slag, mitigated solid waste secondary pollution, clarified mechanisms, and supported steel slag high-value utilization and upgrading of metallurgical green processes.

Omipalisib (OMP) is a powerful dual inhibitor of the mTOR and PI3K enzymes, demonstrating anti-tumor effectiveness in multiple cancer types. No reported UPLC-MS/MS method with in silico metabolism analysis and combined green metrics has been reported for OMP; hence, an ultra-fast, dependable, and eco-friendly UPLC-MS/MS approach was developed for quantifying OMP in human liver microsomes (HLMs) and assessing in vitro OMP metabolic stability. The UPLC-MS/MS method validation conformed to the US-FDA guidelines for bioanalytical approach validation. The StarDrop software package (DEREK and WhichP450 modules) was utilized to identify in silico alerts on the OMP chemical structure and its metabolic lability. The developed UPLC-MS/MS method showed linearity over a concentration range of 1–3000 ng mL⁻¹, accomplished ultra-rapid analysis in 1 minute, and exhibited accuracy and repeatability devoid of HLM effects. OMP and duvelisib (internal standard) were evaluated using an SB-C18 column. The intra- and inter-day evaluations for the precision and accuracy of the UPLC-MS/MS method ranged from −1.05% to 6.67% and −2.04% to 7.67%, respectively. The in vitro half-life (t_1/2) of OMP was 21.07 minutes, and its intrinsic clearance (Cl_int) was 38.48 mL min⁻¹ kg⁻¹. In silico analysis indicates that slight structural modifications to the methoxy group or the pyridazine ring in the process of drug design may increase the safety profile and metabolic stability of new derivatives compared with those of OMP. The integrated in vitro/in silico approach provides a resource-efficient strategy for preliminary metabolic screening and advancing new therapeutic developments aimed at enhancing metabolic stability.

The potential accumulation of copper ions (Cu²⁺) in the food chain poses significant risks, making it imperative to develop efficient tools for real-time monitoring of Cu²⁺ levels in food, plants, and biological systems. In this study, two novel fluorescent probes, RC-1 and RC-2, were synthesized using triphenylamine derivatives through a condensation reaction for the detection of Cu²⁺. Among the two probes, probe RC-2, which contains 4-aminobenzamide, exhibited excellent selectivity, ultra-fast response (<30 s), a low detection limit of 26.8 nM, high water solubility, and ease of synthesis. Probe RC-2 demonstrated effective quantitative monitoring of Cu²⁺ in various food and water samples. The analytical performance showed satisfactory accuracy (80.0–118.9%) and good precision, as evidenced by relative standard deviation (RSD) values below 10%. The accuracy of the method was further substantiated via inductively coupled plasma mass spectrometry (ICP-MS). A Mini Program based on WeChat was designed for Cu²⁺ quantification in food samples, simultaneously enhancing public awareness of food safety. This study highlighted the significant potential of integrating smartphones with fluorescent probes for enhanced monitoring of food safety. Finally, RC-2 was successfully applied for imaging Cu²⁺ in HeLa cells and plant tissues, highlighting its potential for selective detection of Cu²⁺ in complex matrices.

In this work, novel cobalt-doped carbon dots (Co-CDs) were constructed via a facile single-step hydrothermal synthesis approach utilizing vitamin B12 (VB12) and L-tryptophan (L-Try) as precursors. Co-CDs illustrated exceptional peroxidase-like (POD) reactivity. A dual-mode analytical platform integrating fluorescence and UV-vis colorimetry was established based on the catalytic properties of Co-CDs, which can specifically quantify NO₂⁻ across diverse environmental matrices with high accuracy and low detection limit (123.1 nM). Additionally, a smartphone-assisted colorimetric analytical method was established for on-site monitoring of NO₂⁻ with satisfactory recoveries (92.905–106.2%) in real water samples. More importantly, the antimicrobial applications of Co-CDs were explored, and strong antibacterial performances were observed against E. coli and S. aureus. This research not only presents a novel strategy for constructing a highly catalytic nanozyme for highly sensitive detection of NO₂⁻ but also provides a versatile platform bridging advanced nanomaterials with point-of-care detection technologies.

Quantification of biofouling is a complex task that often involves counting both isolated and tightly packed groups of organisms on a test surface. Mussel larvae, which settle as both individuals and as clumps, are an important fouling organism because adult mussel colonies form via the settlement of larvae, making the settlement or repellence of mussel larvae a good indicator of a surface's antifouling performance. Manual quantification methods are time-consuming, and existing automatic machine learning-based methods are poorly suited for use by coding non-experts and often lack the ability to detect both isolated and grouped organisms in one workflow. The objective of this work was to develop a machine learning-based application that is user-friendly and well-suited to the quantification of biofouling. We developed M-Count, an application that combines a neural network object detection model for individual organism detection and a color thresholding algorithm for grouped organism detection. M-Count was demonstrated on the quantification of mussel larvae on sample surface images obtained from a previously developed mussel larvae fouling assay. This study revealed three important characteristics of M-Count: speed, consistency, and accuracy. The primary benefit of M-Count is its speed, being 60× faster than manual counting. The secondary benefit of M-Count is consistency, as it performs the same task repeatedly without bias. Finally, these benefits are obtained while maintaining good accuracy, with the normalized average maximum residual being 0.220 for M-Count and 0.209 for manual counting.

Ensuring the accuracy and reliability of liquid chromatography–mass spectrometry (LC–MS/MS)-based proteomic analysis requires robust quality control (QC) strategies. However, widely used cell line-based QC materials present challenges in reproducibility, scalability, and ethical compliance. In this study, we developed a microalgae-derived QC material based on Synechocystis sp. PCC6803 and evaluated its suitability for LC–MS/MS system performance monitoring. The Synechocystis-based QC samples demonstrated high identification reproducibility, with 76% of the protein groups being consistently detected across five replicates and maintaining a median coefficient of variation (CV) of 6.7% in quantitative precision. Furthermore, QC peptides exhibited excellent linearity (R² ≥ 0.98) and reproducibility (CV ≤ 12.06%) across varying injection amounts. These results indicate that Synechocystis-derived QC materials provide a reproducible and scalable approach that complements conventional QC workflows. They are particularly well suited for routine LC–MS/MS system performance monitoring in proteomics workflows involving non-human or mixed biological samples.

Effective monitoring of chloramphenicol (CAP), a banned antibiotic in food-producing animals due to serious human health risks, demands highly sensitive and cost-efficient analytical methods suitable for complex matrices. This study presents a novel hybrid approach integrating modified QuEChERS extraction, molecularly imprinted polymer solid-phase extraction (MIP-SPE) clean-up, and derivatization-free chrome azurol S (CAS)/Fe(III) spectrophotometric detection for CAP quantification in beef, milk, and eggs. Key innovations include (1) optimization of QuEChERS using a ternary solvent system (acetonitrile : acetone : water, 75 : 20 : 5, v/v/v), significantly enhancing CAP solubility (15.8 mg mL⁻¹) and recovery (94 ± 3%) while suppressing matrix effects (9%); (2) implementation of SupelMIP®SEP cartridges for highly selective CAP isolation, eliminating >90% of interferents with minimal cross-reactivity (e.g., thiamphenicol: 2.1%); and (3) exploitation of a pH-dependent (5.0–5.5) coordination reaction between CAP's hydroxyl groups and the Fe(III)–CAS complex, inducing a distinct bathochromic shift (480 nm → 545 nm) for specific quantification. Rigorously validated per ICH guidelines, the method demonstrates exceptional performance: high sensitivity (LOD: 0.1 µg kg⁻¹; LOQ: 0.3–0.4 µg kg⁻¹, meeting the stringent EU MRL of 0.3 µg kg⁻¹), excellent accuracy (recoveries: 85.2–103.6%; RSD ≤ 7.8%, n = 6), and superior specificity (negligible interference from endogenous components and structural analogs, <5% signal deviation). This rapid 45-minute workflow achieves HPLC-MS/MS-level sensitivity at minimal cost ($0.50–$1.00 per sample) using standard UV-Vis instrumentation. It outperforms immunoassays by reducing cross-reactivity and conventional colorimetry by eliminating derivatization, offering a robust, field-deployable solution for reliable CAP screening and quantification in resource-limited settings.

A ratiometric fluorescence resonance energy transfer (R-FRET) sensor based on two-dimensional Ti₃C₂T_x MXene nanosheets has been developed for intracellular miRNA-21 detection. The sensor comprises MXene nanosheets and two hairpin probes labeled with FAM (H1) and TAMRA (H2). MXene functions as a fluorescence quencher to suppress background noise, while FAM and TAMRA serve as the donor-acceptor FRET pair. Upon introduction of target miRNA-21, a catalyzed hairpin assembly (CHA) reaction is initiated, leading to the formation of an H1-H2 hybrid duplex. This brings the FAM and TAMRA fluorophores into proximity, facilitating efficient FRET. Quantitative detection of miRNA-21 is achieved by recording fluorescence spectra and calculating the intensity ratio (F_TAMRA/F_FAM). In vitro experiments demonstrated a linear response range from 100 pM to 20 nM with a limit of detection (LOD) of 40 pM. Furthermore, the sensor successfully quantified miRNA-21 expression levels within HeLa cells, indicating its potential as a promising platform for early cancer diagnosis.

Methazolamide, a carbonic anhydrase inhibitor, is widely used in the treatment of acute angle-closure glaucoma, chronic open-angle glaucoma, secondary glaucoma, and for reducing intraocular pressure during ophthalmic surgeries. This study established and validated a highly selective and sensitive ultra-high-performance liquid chromatography coupled with quadrupole-orbitrap mass spectrometry (UHPLC-Q-Orbitrap MS) analytical method for quantifying methazolamide in plasma. The separation of methazolamide and acetazolamide (internal standard) was conducted using a BEH Shield RP18 column. The mobile phase employed a gradient elution with acetonitrile (solvent A) and water containing 0.1% formic acid (solvent B). Data collection was executed in the positive ionization mode, employing comprehensive full MS/dd-MS2 on a Q-Orbitrap mass spectrometer. Methazolamide and acetazolamide (internal standard) were well resolved, with retention times of 2.63 min and 1.52 min, respectively. Methazolamide exhibited a robust linear correlation over a plasma concentration range of 10–5000 µg L⁻¹, with a lower limit of quantification established at 10 µg L⁻¹. The precision and accuracy were maintained below 8%, with methazolamide extraction recovery from plasma ranging between 86.16% and 96.06%. This research introduces an efficient method for the quantification of methazolamide. The validated method effectively assessed methazolamide pharmacokinetics in rat plasma following a 2 mg kg⁻¹ oral dose.

In the field of global health, the quality of Traditional Chinese Medicine (TCM) holds pivotal significance. Ensuring the clinical efficacy and medication safety of TCM not only enhances international trust in TCM, injecting strong impetus into the process of TCM globalization, but also promotes the dissemination of traditional medical culture, strengthens cultural exchanges between China and foreign countries, enriches the global medical system, and realizes complementary advantages with modern medicine. In recent years, the application of fingerprinting combined with chemometrics in TCM quality evaluation has attracted increasing attention from both academic and industrial circles. Among them, fingerprinting technology can intuitively display the overall characteristics and internal correlations of chemical components in TCM, while chemometrics, by means of multivariate statistical analysis, pattern recognition and other methods, performs dimensionality reduction on fingerprint data, constructs new models, and thus deeply excavates the potential effective information hidden in the data. The synergistic application of these two technologies in TCM quality evaluation shows significant advantages: in terms of TCM origin tracing, it can accurately analyze the differences in TCM components under different producing areas and growth environments, realizing precise traceability of medicinal materials; in the work of authenticity identification, it can effectively identify counterfeits by comparing characteristic fingerprints and data differences, ensuring the authenticity of medicinal materials; in the content determination link, combined with chemometric algorithms, it can realize simultaneous quantitative analysis of multiple components, improving detection efficiency and accuracy; for compound TCM, this technology combination can comprehensively consider the interactions among various components to conduct comprehensive quality evaluation. This article systematically reviews the research progress of the integration of this technology in the field of TCM quality evaluation in recent years, elaborates on the research overview in various key links and the specific methods of compound medicine quality evaluation, and looks forward to its future development trends and application prospects. It aims to provide strong support for constructing a standardized, standardized and comprehensive theoretical research system of TCM, and help realize the goals of precision, clarity, predictability and controllability of TCM quality.