Analytical and Bioanalytical Chemistry最新文献

This study developed a nanozyme-SERS dual-function sensor that exhibits both highly efficient peroxidase (POD)-like activity and superior surface-enhanced Raman spectroscopy (SERS) enhancement, designed for detecting homocysteine (Hcy) in serum from colorectal cancer (CRC) patients. Bimetallic Au@Pt nanoparticles (Au@Pt NPs) exhibited exceptional nanozyme catalysis and SERS performance, enabling the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to oxidized TMB (oxTMB) with a pronounced SERS signal generation. Au@Pt NPs were assembled into aminated capillaries via electrostatic adsorption and subsequently modified with Hcy aptamers to create the nanozyme-SERS dual-function sensor. When Hcy was present, the reducing thiol groups (-SH) consumed the hydroxyl radicals (·OH) produced by the decomposition of H₂O₂. This inhibited the oxidation of TMB, resulting in a weaker SERS signal. The SERS sensor demonstrated a remarkably low detection limit (LOD) for Hcy, reaching as low as 0.14 × 10⁻¹² mol/L. Furthermore, within the concentration range of 10⁻¹² to 10⁻⁴ mol/L, there was a linear relationship between the logarithm of Hcy concentration and the SERS signal intensity. Serum samples from both healthy individuals and CRC patients were tested with the SERS sensor. The results demonstrated a high degree of concordance with those obtained by the enzyme-linked immunosorbent assay (ELISA), showing significantly higher Hcy levels in CRC patient serum compared to healthy controls. Unlike traditional methods such as colorimetric assays, fluorescence analysis, and the SERS "sandwich" strategy, which often involve complex procedures and have low sensitivity, this approach offers a simple, highly sensitive, and specific method for detecting Hcy. It holds promise as an effective tool for early CRC diagnosis.

Comprehensive profiling of impurities in organophosphorus pesticides, such as dimethoate, remains challenging due to their structural diversity, trace abundance, and analytical constraints. This can be overcome by integrating multiple analytical techniques to enhance impurity profiling of pesticides, particularly dimethoate, but little has so far been carried out in this field. Herein, a novel integrated analytical platform, synergizing high-performance liquid chromatography-diode array/charged aerosol detection (HPLC-DAD-CAD) with Orbitrap high-resolution mass spectrometry, empowered by MS-DIAL/SIRIUS artificial intelligence-driven annotation, was developed. The chromatographic conditions (column, mobile phase additive, organic phase, sample solvent, and gradient program) were optimized. The dual-detector synergy strategy simultaneously captured chromophoric and attenuated chromophoric species. Innovatively coupling MS-DIAL and SIRIUS identified three known impurities and 15 novel structures by a workflow leveraging spectral deconvolution, sub-ppm molecular formula prediction, and fragmentation modeling. Under the optimized setting, the method achieved a detection limit of 0.03 µg g⁻¹ and trace level sensitivity ≥0.01%. The fragmentation pathways were also demonstrated for a total of three key impurity classes (phosphorothioate esters, disulfide-linked compounds, and alkyl-modified derivatives), linking their formation with synthetic routes and storage degradation. Overall, the proposed extensible analytical framework establishes the foundation for pesticide impurity surveillance, strengthening reference material certification, production optimization, and agrochemical safety governance.

In time-of-flight secondary ion mass spectrometry (ToF-SIMS), analysis of frozen biological specimens at cryogenic temperatures is often necessary to maintain the native 3D structure of the specimen. Frozen hydrated analysis results in interferences from sputtered water cluster peaks that extend over the full spectral mass range. In this study, we have investigated the influence of the analysis temperature from 98 to 183 K on the water cluster spectrum from a frozen hydrated cell-free model biofilm system which contained the antibiotic ciprofloxacin. Below 163 K, the spectrum was dominated by sequences of water cluster ions of the form (H₂O)_nX⁺, where X⁺ is either H⁺, NH₄⁺, or one of at least 16 other small cations. These sequences repeat every 18 mass units. These sequences of water cluster ions begin at m/z 19 and extend to over m/z 2000. Different temperature trends were observed for each cationized water cluster sequence. At a temperature of 153 K, just below the onset of freeze-drying, the (H₂O)H⁺ cluster signals decline, and many cationized cluster signals go through a local minimum. In this same temperature region, an increase in proton mobility was observed in experiments using D₂O. The decline in water cluster ion signals at 153 K was accompanied by an increase in the [ciprofloxacin+H]⁺ signal as well as an increase in signals from other organic molecules. Based on these results, 153 K is recommended as the optimum temperature for analysis of ciprofloxacin in frozen hydrated specimens.

Amyloid-beta (Aβ) oligomers are key contributors to the pathology and progression of Alzheimer's disease (AD), making their characterization essential for understanding aggregation processes and developing potential therapeutic strategies. This study provides a systematic framework for analyzing Aβ(1-42) oligomers in vitro using cyclic ion mobility-mass spectrometry (cIMS). Compared to previous generations of traveling wave ion mobility (TWIM) devices, the cIMS platform offers superior resolution through its scalable ion mobility path length. However, the multistage character of the cIMS platform requires thorough investigation of parameters affecting oligomer transmission and activation to ensure reliable analysis of labile and dynamic systems such as Aβ oligomers. Our findings highlight the critical influence of cone voltage (CV) on in-source ion activation, subsequent structural changes, and oligomer detection. By balancing CV, we achieved detection of a broad range of oligomeric species while limiting their activation and maximizing signal intensity. Moreover, we present the first comprehensive set of optimized ion optics and ion mobility parameters that enable effective transmission and separation of oligomer Aβ(1-42) ions. Using the optimized method, we successfully detected a spectrum of Aβ(1-42) oligomers ranging from dimers to dodecamers. Additionally, the method was applied in collision-induced unfolding experiments, revealing size-dependent conformational transitions proving its applicability. This optimized cIMS methodology establishes a foundation for future studies on Aβ(1-42) aggregation mechanisms, AD pathogenesis, and therapeutic applications. Furthermore, our results offer valuable insights into cIMS instrument tuning, with potential applications in the analysis of other complex biological systems.

The accurate and rapid detection of fluoroquinolone antibiotics (FQs) is crucial, yet their structural homology often leads to cross-reactivity that compromise accuracy. Herein, we designed a poly(3,4-ethylenedioxythiophene) doped with a poly(styrenesulfonate) (PEDOT:PSS)-based dual-channel organic electrochemical transistor (OECT) array on a flexible, low-cost polyimide substrate. By leveraging the synergistic catalysis of single-walled carbon nanotubes (SWCNTs) and gold nanoparticles (AuNPs), effective discrimination of three FQs was achieved using gate electrodes modified with only two Nafion/SWCNTs/AuNPs composites, differing solely in AuNP mass fraction-this significantly simplifies fabrication for an electronic tongue system (ETS). Aided by principal component analysis (PCA), the system discriminates and quantifies ofloxacin (OFL), levofloxacin (LEV), and ciprofloxacin (CIP) across a wide concentration range of 0.4-1000 μM, with limits of detection (LODs) of 0.32-0.40 μM, while exhibiting excellent selectivity, anti-interference, consistency, stability, and rapid response. The comprehensive performance of this platform establishes a practical foundation for portable FQ sensing in environmental and clinical applications.

The development of feasible, low-cost, and long-persistent chemiluminescence (CL) systems is highly desirable for enhancing detection reproducibility and accuracy. Here, we present a space-confined CL system based on the LHC@G capsules, which are prepared via a one-pot ultrasound-assisted method to co-encapsulate glucose oxidase (GOx), hemin (a peroxidase mimic), and luminol within an oil-in-water structure. The LHC@G capsules are used for producing glow-type CL emission. Specifically, glucose is catalyzed by GOx on the capsule surface, yielding H₂O₂. The H₂O₂ then diffuses into the oil core and undergoes hemin-catalyzed in situ blue emission of luminol. The LHC@G capsule-based CL system exhibits intensive and prolonged blue emission for over 1500 s, with a nearly threefold enhancement in CL intensity compared to that of luminol solution. Mechanistic studies reveal that the excellent CL performance stems from a highly efficient cascade reaction and regulated diffusion. The proposed capsule CL system exhibits excellent reproducibility and storage stability, and has been successfully developed for simple, fast, and sensitive visual glucose detection with a LOD of 1.21 μM. This work provides a convenient strategy for constructing long-persistent and accurate CL systems in the field of point-of-care testing (POCT).

The species of Theobroma grandiflorum, commonly known as cupuassu, is widely used in the production of various cosmetic and food products. However, cupuassu seed shell (CSS), a major agro-industrial residue generated during the processing of its seeds, remains largely underexplored. In this study, a dual-extraction strategy was developed to valorize CSS using green chemistry principles, emphasizing waste recovery, reduced solvent consumption, and lower environmental impact. This methodology was applied to the extraction of theobromine, a methylxanthine of growing interest in the development of nutraceuticals and functional foods. In the first step, lipids were extracted using the energized dispersive guided extraction (EDGE) system, an automated and sustainable alternative to conventional methods. Fatty acids analysis revealed an oil profile like that of commercial cupuassu seed oil, reinforcing the potential of CSS oil as a functional ingredient in food, pharmaceutical, or cosmetic applications. In the second step, defatted CSS solid residue was subjected to theobromine extraction using the same EDGE system, this time employing a natural deep eutectic solvent (NADES) composed of choline chloride and glycerol (1:3). Extraction conditions were optimized using a BBD (Box-Behnken Design), with the best results achieved at 150 °C, 15 min, and 80% NADES, yielding 0.62 mg g^-1 in dry basis (d.b.) of theobromine. This study demonstrates a sustainable and efficient approach to convert a low-value byproduct into high-value bio-based compounds, highlighting the versatility of the EDGE system and reinforcing the principles of a circular economy and green analytical chemistry.

Herbal remedies contain various phenolic compounds. However, it remains difficult to identify the most important bioactive components and compare their effectiveness in different plant species. In this study, effect-directed analysis has been applied to five European medicinal plants. Angelica archangelica, Angelica sylvestris, Agrimonia eupatoria, Sambucus ebulus, and Sambucus nigra have been analyzed to unravel and compare their phenolic profiles and antioxidant potential. Plant extracts obtained by a sustainable microwave-assisted extraction method were fractionated using semi-preparative liquid chromatography to yield continuous fractions, and a miniaturized ABTS radical scavenging assay of the fractions was used to screen for antioxidant activity. Highly active fractions were selected for a second HPLC fractionation and analyzed with a quadrupole time-of-flight mass spectrometer using a non-targeted workflow that successfully linked antioxidant effects to specific compounds or compound classes. In the richest antioxidant fractions, flavan-3-ol oligomers such as procyanidin C1 were found in A. eupatoria, the flavonol glycoside rutin and other co-eluting phenolics in S. nigra. In contrast, A. archangelica showed a distinct metabolite profile rich in coumarins (e.g., bergapten, umbelliferone), but they contributed less to antioxidant activity compared to the flavonoid-dominated profiles of the other species. Overall, leaves and flowers contained the highest diversity and quantity of phenolic antioxidants among the plants studied. The effect-directed analysis of multiple European medicinal plants demonstrated its utility in exploring the major antioxidant compounds and highlighted significant differences in phenolic composition and antioxidant activity between species and plant parts.

Mass spectrometry combined with stable isotope labeling is a powerful technique for detecting disease-related changes in glycosylation patterns and identifying potential biomarkers. However, stable isotope labeling reagents that simultaneously offer high sensitivity, low cost, and stable sialic acid modifications remain scarce. In this study, we developed a convenient and cost-effective microwave-assisted method for synthesizing a stable isotopic quaternary phosphonium hydrazide labeling reagent pair, ¹⁴N/¹⁵N-P₄HZD, for the quantitation difference analysis of N-glycans using HPLC-ESI-HRMS with high sensitivity and convenience. This strategy features high labeling efficiency, excellent reproducibility, and strong linearity (R² = 0.9984) within a dynamic range spanning two orders of magnitude. The reagent pair is compatible with multiple ion source mass spectrometers and front-end chromatographic separation technologies. In particular, it enhances the ionization efficiency of sialylated N-glycans and facilitates their detection. The relative quantification method has been effectively applied to analyze the variations in N-glycomic profiles from two muscular atrophy models induced by simulated microgravity, specifically the C2C12 cell and hindlimb unloading mouse serum. We discover that these variations display characteristic relevance in both models. N-Glycans Man₃GlcNAc₃Fuc₁ and Man₃GlcNAc₄Gal₁Fuc₁Sia₁ exhibit their potential as biomarkers for the early diagnosis of muscular atrophy. The mass spectrometry method based on the ¹⁴N/¹⁵N-P₄HZD reagent pair offers a convenient and feasible strategy for the difference analysis of N-glycomics, demonstrating significant potential for application in the discovery of clinical biomarkers.