Analytica Chimica Acta最新文献

{"title":"Detailed impurity profiling of graphene oxide fractions by robust inductively coupled plasma optical emission spectrometry monitoring","authors":"Iuliia A. Poimenova ,&nbsp;Elizaveta Yu. Zhukova ,&nbsp;Svetlana T. Ovseenko ,&nbsp;Nikita S. Saratovsky ,&nbsp;Ivan K. Kiryukhin ,&nbsp;Daria-Mariia V. Ratova ,&nbsp;Dmitrii M. Filatov ,&nbsp;Anastasia M. Alekseeva ,&nbsp;Svetlana V. Smirnova ,&nbsp;Mikhail A. Proskurnin ,&nbsp;Ivan V. Mikheev","doi":"10.1016/j.aca.2026.345140","DOIUrl":"10.1016/j.aca.2026.345140","url":null,"abstract":"<div><h3>Background</h3><div>Graphene oxide (GO) is widely used in biomedicine and biotechnology due to its aqueous dispersibility and potential nanozyme activity. However, it remains analytically challenging because of structural heterogeneity and metallic inclusions, which affect its functional performance. GO therefore requires precise trace metal analysis, as even minor compositional variations can be critical. Modern multi-element analysis demands results that are both reliable and accurate, yet sound laboratory practice is not always followed. Although ICP-OES offers high sensitivity and precision, metrological rigor is often lacking. This work addresses the need for validated and robust elemental analysis of GO bulk material and particle-size fractions.</div></div><div><h3>Results</h3><div>ICP-OES was employed to quantify metals in bulk GO and to characterize Mn and Ti distribution in GO fractions. A fast algorithm was developed to identify robust plasma conditions by mapping the Mermet coefficient (Mg II/Mg I intensity ratio) across a range of flow rates and RF power levels. Concentrations for selected elements in the bulk material ranged from 10⁻¹ to 10³ mg kg⁻¹; in aqueous dispersions, values reached up to 10³ mg L⁻¹. Validation parameters for Mn, Ti, and Fe included recoveries of 85–115 %, detection limits of 0.1–0.3 ng kg⁻¹ (for used weight ca. 50 mg), and intra-/inter-day RSDs not exceeding 7 %. The Mermet coefficient exhibited an RSD of ∼0.6 %, indicating minimal matrix interference. Fraction analysis revealed a monotonic decrease in Mn toward fractions with smaller lateral-size cut-offs. ATR-FTIR spectra were obtained for stirred, purified, and ultrasound-treated GO fractions to assess whether purification altered the surface functional groups.</div></div><div><h3>Significance</h3><div>This study provides a validated approach for trace metal analysis in GO, combining sensitivity, robustness, and reproducibility across both bulk solid and aqueous dispersion forms. By experimentally examining the influence of plasma conditions on analytical performance, it offers the first systematic assessment of GO-specific ICP-OES parameter optimization. The results support more reliable characterization of GO materials and enable improved quality control in applications where elemental composition critically affects functionality.</div></div>","PeriodicalId":240,"journal":{"name":"Analytica Chimica Acta","volume":"1392 ","pages":"Article 345140"},"PeriodicalIF":6.0,"publicationDate":"2026-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146072876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Post-esterification preparation of carboxyl groups enriched magnetic microporous organic network for the efficient enrichment and determination of quaternary ammonium alkaloids","authors":"Jian-Ming Liu ,&nbsp;Jian Liu ,&nbsp;Tian-Tian Ma ,&nbsp;Cheng-Xiong Yang","doi":"10.1016/j.aca.2026.345173","DOIUrl":"10.1016/j.aca.2026.345173","url":null,"abstract":"<div><h3>Background</h3><div>Microporous organic networks (MONs) are an emerging class of porous materials characterized by extremely large surface area, tunable topology, and superior stabilities, which have received increasing attention in sample pretreatment. However, their superhydrophobic nature has largely limited their application scope. The synthesis of functionalized MONs has proved to be a feasible strategy to broaden their utility. Nevertheless, this approach remains constrained by the limited variety and availability of functionalized monomers. Therefore, developing novel post-synthetic modification strategies is crucial for expanding the functionality and applications of MONs, particularly in trace analyte enrichment.</div></div><div><h3>Results</h3><div>Herein, we present a novel post-esterification strategy to synthesize a new carboxyl groups enriched magnetic MON (MMON-2COOH) for the highly efficient magnetic solid-phase extraction (MSPE) of four quaternary ammonium alkaloids (QAAs) from complex urine samples. The resulting MMON-2COOH not only retains the porous structure, excellent solvent and thermal stability, and rapid magnetic responsiveness of its precursor (hydroxyl-functionalized magnetic MON) but also incorporates conjugated networks and abundant carboxyl groups. This enables efficient extraction of QAAs through multiple interactions, including π-π stacking, hydrogen bonding, and electrostatic attraction. After optimization of extraction factors, an analytical method integrating MMON-2COOH-based extraction with HPLC-UV detection was established, achieving sensitive and selective determination of QAAs with low limits of detection of 0.05–0.5 μg L⁻¹ and limits of quantification of 0.5–1.0 μg L⁻¹, wide linear range of 0.5–1000 μg L⁻¹, negligible matrix effect of 0.88–1.09, rapid extraction of 2 min, and less adsorbent consumption of 2 mg.</div></div><div><h3>Significance</h3><div>This is the first example of post-esterification preparation of carboxyl groups functionalized MON. The results demonstrate that MMON-2COOH is a highly effective adsorbent, and the developed method is suitable for accurate determination of QAAs in biological samples. This work highlights the significant potential of post-esterification as a versatile approach for designing high-performance adsorbents in sample pretreatment.</div></div>","PeriodicalId":240,"journal":{"name":"Analytica Chimica Acta","volume":"1392 ","pages":"Article 345173"},"PeriodicalIF":6.0,"publicationDate":"2026-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146072869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Establishment of a rapid colorimetric sensor for Microcystin-LR based on specific aptamer and positively charged gold nanoparticles","authors":"Xueting Cui ,&nbsp;Jun Wang ,&nbsp;Tingyu Hou ,&nbsp;Ming Cai ,&nbsp;Luozhao Wang ,&nbsp;Yanna Liu ,&nbsp;Jinhua Li","doi":"10.1016/j.aca.2026.345139","DOIUrl":"10.1016/j.aca.2026.345139","url":null,"abstract":"<div><div>Eutrophication of surface freshwater drinking sources intensifies, leading blue-green algae to release massive microcystins. Microcystin-LR (MC-LR), the most toxic variant, poses severe threats to public health and environmental safety. Conventional MC-LR detection methods rely on bulky, expensive equipment and involve complex, time-consuming sample pretreatment, making them unsuitable for on-site testing. This study developed a colorimetric sensing platform based on the binding of positively charged gold nanoparticles (AuNPs) to MC-LR aptamers for simple and rapid MC-LR detection. Without MC-LR, positively charged gold nanoparticles bind to negatively charged aptamers, aggregate, and turn the solution from yellow to white. This method exhibits high sensitivity (detection limit: 0.1 μg/L) and good specificity (insensitive to interferents like MC-YR and MC-RR), with a total assay time of 55 min, providing a rapid alternative to conventional laboratory-based methods like ELISA. Tests on actual water samples showed recoveries of 96.1–119.8% with relative standard deviations &lt;10%, demonstrating good accuracy and precision for real environmental water analysis. The method's performance suggests its potential for on-site screening, although some variability was observed in complex matrices. This visualized assay eliminates reliance on large instruments, shortens detection time, and holds great potential for environmental water sample testing.</div></div>","PeriodicalId":240,"journal":{"name":"Analytica Chimica Acta","volume":"1392 ","pages":"Article 345139"},"PeriodicalIF":6.0,"publicationDate":"2026-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146072867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CuAg NCs with AIE Effect Coordinated by Ce3+ as a Novel Fluorescent Probe for the screening of ATP inhibiting drugs","authors":"Jinwen Chen,&nbsp;Huixiao Tong,&nbsp;Yuqing Wang,&nbsp;Yinghui Dang,&nbsp;Ziheng Gu,&nbsp;Ruijue Liu,&nbsp;Shenghua Liao","doi":"10.1016/j.aca.2026.345170","DOIUrl":"10.1016/j.aca.2026.345170","url":null,"abstract":"<div><h3>Background</h3><div>In recent years, bimetallic nanoclusters (NCs) have emerged as promising functional materials, particularly those exhibiting aggregation-induced emission (AIE) properties. Compared to single-metal systems or organic AIE fluorophores, they offer enhanced fluorescence, superior stability, straightforward synthesis, and excellent biocompatibility. This has enabled them to attract considerable attention in the field of chemical sensing and bioimaging. Specifically, adenosine triphosphate (ATP) serves as a critical biomarker, and the development of sensitive fluorescent probes for its detection is of significant importance in biomedical research and clinical diagnostics.</div></div><div><h3>Results</h3><div>This study developed a mitochondrial-targeted fluorescent probe based on Ce³⁺- coordinated copper–silver bimetallic nanoclusters (CuAg NCs), designed for selective ATP recognition and ATP-inhibiting drugs screening. The AIE-active CuAg NCs were synthesized via a facile approach using <span>l</span>-glutathione (GSH) as both reducing agent and stabilizing ligand. Upon addition of Ce³⁺, the quantum yields (QYs) increased from 0.60% to 22.64%. This attributed to the suppression of non-radiative relaxation pathways in the excited states through coordination interaction between Ce³⁺ and carboxyl groups (-COOH) of surface-anchored GSH ligands. Leveraging the coordination between Ce³⁺ and the triphosphate moiety of ATP, a turn-off fluorescent probe was constructed, demonstrating a linear response within 1–30 μM and a detection limit of 0.105 μM. Owing to its biocompatibility and inherent mitochondrial-targeting ability, it enabled effective intracellular ATP monitoring. In HepG2 cells, fluorescence intensity showed clear dose-dependence upon treatment with ATP-activator (Glimepiride) and ATP-inhibitor (Imatinib).</div></div><div><h3>Significance and novelty</h3><div>This work not only presents a sensitive and selective probe for ATP determination but also establishes a versatile platform for real-time tracking of intracellular ATP levels and screening of ATP-modulating drugs. The proposed design strategy based on metal-coordination enhanced bimetallic NCs offers a novel pathway for developing organelle-targeted functional probes, highlighting its potential in biomedical sensing and pharmacological research.</div></div>","PeriodicalId":240,"journal":{"name":"Analytica Chimica Acta","volume":"1392 ","pages":"Article 345170"},"PeriodicalIF":6.0,"publicationDate":"2026-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146095662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-performance liquid chromatography enables purification of red-emitting carbon dots for cellular imaging","authors":"Manivannan Madhu ,&nbsp;Sih-Ying Chen ,&nbsp;Po-Chiao Lin ,&nbsp;Wei-Lung Tseng","doi":"10.1016/j.aca.2026.345176","DOIUrl":"10.1016/j.aca.2026.345176","url":null,"abstract":"<div><h3>Background</h3><div>The hydrothermal method is widely employed for the synthesis of carbon dots (CDs); however, the resulting products often contain complex compositions, leading to inaccurate morphological and photophysical characterization and reducing their reliability in applications. In this study, reversed-phase high-performance liquid chromatography (RP-HPLC) was employed to fractionate the heterogeneous products generated from the hydrothermal treatment of resorcinol.</div></div><div><h3>Results</h3><div>Ten distinct fractions were well-separated by RP-HPLC, followed by comprehensive characterization through spectroscopic and electron microscopy-related techniques. Among these fractions, the CDs in fraction 7 (designated F7-CDs) exhibit the highest quantum yield (50%), excellent photostability, and abundant hydroxyl and carboxylic acid groups. Transmission electron microscopy further reveals, the F7-CDs behave as crosslinked polymer-encapsulated CDs. To enable the F7-CDs to image specific organelles, they were functionalized with cysteine via 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-sulfohydroxysuccinimide coupling, followed by conjugation with a maleimide–poly(ethylene glycol)–succinimidyl carbonate linker, and subsequently attached to amine-terminated triphenylphosphonium (TPP) or morpholine (MP). The TPP- and MP-conjugated F7-CDs exhibited strong colocalization with MitoView and LysoView 488, respectively, confirming their ability to target mitochondrial and lysosomal compartments. In contrast, their negligible overlap with nuclear stains and a relatively poor colocalization with non-targeting organic dyes demonstrate that the high organelle-targeting selectivity is highly connected with the surface ligands of the F7-CDs.</div></div><div><h3>Significance</h3><div>Collectively, RP-HPLC is a powerful purification method for producing high-quality CDs, well-suited for surface ligand engineering in cellular imaging. Notably, this work reports the very first example of red-emitting CDs that retain strong luminescence and biocompatibility after chromatographic purification, demonstrating their potential for cellular imaging.</div></div>","PeriodicalId":240,"journal":{"name":"Analytica Chimica Acta","volume":"1392 ","pages":"Article 345176"},"PeriodicalIF":6.0,"publicationDate":"2026-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146095759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"DPPH Rf-shift assay to overcome spectral interference: A rapid, portable TLC-based approach for semi-quantitative antioxidant evaluation","authors":"Garima Singh,&nbsp;Perinkulam Ravi Deepa,&nbsp;Prabhat Nath Jha","doi":"10.1016/j.aca.2026.345160","DOIUrl":"10.1016/j.aca.2026.345160","url":null,"abstract":"<div><div>Accurate assessment of antioxidant activity is essential for evaluating compounds in food, pharmaceutical, and biomedical research. Conventional methods, such as the DPPH spectrophotometric assay, are widely used due to their simplicity but are limited by false-negative responses, spectral interference from coloured compounds, relatively higher sample usage, and dependence on costly instrumentation. Alternative approaches, including TLC/HPTLC-DPPH and HPLC-based assays, only partially overcome these limitations and often face challenges in quantification or accessibility. Therefore, there is a need for a rapid, reliable, and colour-independent method to quantify antioxidant activity in both coloured and non-coloured compounds.</div><div>We developed the DPPH R_f–Shift Assay, a TLC-based method that quantifies antioxidant activity by separating the oxidized DPPH radical (DPPH∗) from its reduced form (DPPH-H) based on polarity differences, producing a measurable shift in R_f values. Antioxidant activity was quantified using a TLC Documentation System as the ratio of R_f_DPPH-H/R_f_DPPH∗, with values ≥ 1 indicating significant activity. Validation with five reference antioxidants (BHT, α-tocopherol, ascorbic acid, pyrogallol red, β-carotene) and a coloured non-antioxidant control (synthetic azo dye, amaranth) revealed that the DPPH R_f–Shift Assay accurately captured concentration-dependent responses. In contrast, conventional spectrophotometric based DPPH assay overestimated activity for coloured compounds due to spectral interference, producing misleading &gt;100 % scavenging values. The DPPH R_f–Shift Assay resolved these discrepancies, providing clear and reproducible quantification of radical scavenging.</div><div>The DPPH R_f–Shift Assay is a novel, portable, and cost-effective method that overcomes colour interference limitations in antioxidant measurement. By directly resolving DPPH redox states on TLC and enabling image-based quantification, it allows accurate assessment of antioxidant activity in coloured compounds and complex pigment extracts, expanding analytical capabilities for food, pharmaceutical, and natural product research.</div></div>","PeriodicalId":240,"journal":{"name":"Analytica Chimica Acta","volume":"1392 ","pages":"Article 345160"},"PeriodicalIF":6.0,"publicationDate":"2026-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146072874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiplexed potentiometric sensing of nitrite in environmental waters","authors":"Renato L. Gil,&nbsp;Samuel Silva,&nbsp;Marília Barreiros dos Santos,&nbsp;Álvaro Geraldes,&nbsp;Begoña Espiña,&nbsp;Raquel B. Queirós","doi":"10.1016/j.aca.2026.345190","DOIUrl":"10.1016/j.aca.2026.345190","url":null,"abstract":"<div><div>Nitrite is a key water quality indicator whose monitoring is essential for environmental and human safety protection, yet conventional methods such as chromatography and spectrophotometry require expensive instrumentation and centralised laboratory infrastructure. Potentiometric solid-contact ion-selective electrodes, particularly in screen-printed formats, offer a promising cost-effective and miniaturised alternative, but their use in real scenarios still demands versatile operation modes and affordable multiplexed readout to increase throughput and statistical robustness. In this context, a potentiometric nitrite sensor based on commercial screen-printed electrodes (SPEs) modified with graphene oxide and functionalised with an optimised polymeric membrane containing Nitrite Ionophore VI, was developed and characterised for batch, drop, and flow analysis using a custom open-source multiplexer that extends a single-channel EmStat4M potentiostat (PalmSens BV) to eight pseudo-parallel channels. The NO₂–SPEs exhibited a Nernstian response over the linear range from 3.0 × 10⁻⁶ to 1.0 × 10⁻² M under batch, drop, and flow analytical modes, covering nitrite's regulated contaminant level in freshwater. The potentiometric response was additionally characterised by a fast response time (&lt;40 s), good reversibility, reproducibility (RSD &lt;4.3% for slope between identical sensor units, <em>n = 16</em>), and potential stability (medium-term drift of 32.8 ± 15.3 μV min⁻¹) under batch mode. The proposed potentiometric systems were applied to nitrite determination in spiked river and groundwater samples, yielding recovery values from 83.5 to 108.9% across all three operational modes. Beyond these analytical figures of merit, the combined sensor-multiplexer platform provides a practical route toward decentralised measurements, enabling sensing automation, increased statistical sample size, and multianalyte detection capabilities.</div></div>","PeriodicalId":240,"journal":{"name":"Analytica Chimica Acta","volume":"1392 ","pages":"Article 345190"},"PeriodicalIF":6.0,"publicationDate":"2026-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-way data modelling for enhancing classification performance: Fluorescence data as a case of study","authors":"Jorgelina Zaldarriaga-Heredia ,&nbsp;Antonella E. Montemerlo ,&nbsp;José M. Camiña ,&nbsp;Mirta R. Alcaraz ,&nbsp;Silvana M. Azcarate ,&nbsp;Héctor C. Goicoechea","doi":"10.1016/j.aca.2026.345159","DOIUrl":"10.1016/j.aca.2026.345159","url":null,"abstract":"<div><h3>Background</h3><div>The exploitation of multidimensional information represents a key challenge in analytical chemistry, particularly for classification tasks involving complex systems. This study systematically investigates the influence of data structure—ranging from first-to third-order—on classification performance using simulated and experimental fluorescence datasets. Chemometric models based on partial least squares–discriminant analysis (PLS-DA), multi-way PLS-DA (N-PLS-DA), and parallel factor analysis combined with discriminant analysis (PARAFAC-DA) were evaluated under varying conditions of class balance, noise, and sample size. Simulated and experimental datasets based on excitation–emission fluorescence spectroscopy were used.</div></div><div><h3>Results</h3><div>Simulated results demonstrated that increasing data dimensionality markedly enhanced discrimination ability, yielding higher accuracy and reduced error rates. Third-order models achieved average accuracies above 93 %, improving by up to 20 % and 10 % compared to the first- and second-order models, respectively. The methodology was further validated using excitation–emission fluorescence data from extra virgin and virgin olive oils subjected to infrared heating. Both N-PLS-DA and PARAFAC-DA provided successful discrimination, with PARAFAC-DA offering superior interpretability through chemically meaningful component profiles describing degradation and oxidation processes. Overall, the findings confirm that third-order chemometric models effectively integrate structural, spectral, and kinetic information, thereby improving classification reliability and interpretability. Even under conditions of class imbalance and limited sample availability, third-order models maintained low error rates and consistently high accuracy values, confirming their robustness and generalizability.</div></div><div><h3>Significance</h3><div>This study provides a comprehensive evaluation of how data structure influences multivariate classification performance. The proposed approach highlights the analytical potential of higher-order data modelling as a powerful and versatile strategy for classifying complex matrices. The findings firmly establish third-order modelling as a versatile and compelling tool for analytical applications where data complexity and real-world variability are unavoidable.</div></div>","PeriodicalId":240,"journal":{"name":"Analytica Chimica Acta","volume":"1391 ","pages":"Article 345159"},"PeriodicalIF":6.0,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146056528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A peptide-functionalized quantum Dots/MOF nanosheets fluorescence biosensor for glutathione sensing and cellular imaging","authors":"Tongfang Chen ,&nbsp;Jingjie Liang ,&nbsp;Weiqing Liu ,&nbsp;Fengxia Zhou ,&nbsp;Chanci Qiu ,&nbsp;Yuhui Peng ,&nbsp;Xie Zhou","doi":"10.1016/j.aca.2026.345120","DOIUrl":"10.1016/j.aca.2026.345120","url":null,"abstract":"<div><h3>Background</h3><div>Glutathione (GSH), the most abundant cellular non-protein thiol and a central antioxidant, plays essential roles in regulating redox homeostasis, signal transduction, and detoxification processes. Altered GSH levels are closely associated with various pathological conditions, including neurodegenerative disorders, and liver injury. Notably, tumor tissues exhibit markedly elevated GSH concentrations (up to 4–10 times higher than in normal cells), where it promotes tumor proliferation, invasion, and chemoresistance by sustaining a reduced microenvironment, these characteristics make GSH an important biomarker and therapeutic target in oncology.</div></div><div><h3>Results</h3><div>We developed a novel “switch-on” near-infrared (NIR) fluorescence nanoprobe, Ag₂S–CH@Cu-TCPP, for the highly sensitive and selective detection and imaging of GSH. The nanoprobe was constructed by conjugating histidine-rich CH peptides to carboxyl-capped Ag₂S quantum dots (Ag₂S QDs), which were then self-assembled onto two-dimensional Cu-TCPP metal-organic framework (MOF) nanosheets via coordination between Cu²⁺ and imidazole groups. In this design, Cu-TCPP acts as an efficient quencher for the Ag₂S–CH fluorescence via a fluorescence resonance energy transfer (FRET) mechanism. Upon encountering GSH, the reduction of Cu²⁺ to Cu ⁺ disrupts the FRET process, leading to the recovery of the NIR fluorescence signal. This nanoprobe demonstrated a low detection limit of 5.33 μM and a wide linear range from 0.625 to 10 mM for GSH quantification, with excellent selectivity, high reproducibility, and favorable biocompatibility. We successfully applied the platform for monitoring intracellular GSH levels and distinguishing between cancer cells and normal cells based on their differential GSH expression.</div></div><div><h3>Significance and novelty</h3><div>The “switch-on” probe demonstrates excellent biocompatibility and is applicable for cellular imaging. It enables discrimination between normal and cancer cells while supporting semi-quantitative analysis of both endogenous and exogenous GSH. This work provides a novel and reliable strategy for tumor diagnosis and advanced investigations into GSH-related biological processes.</div></div>","PeriodicalId":240,"journal":{"name":"Analytica Chimica Acta","volume":"1391 ","pages":"Article 345120"},"PeriodicalIF":6.0,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146042957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synthesis, characterization, and application of sorbents for the mixed-mode extraction of antisense oligonucleotides from cerebrospinal fluid samples","authors":"Karolina Ostrowska ,&nbsp;Maria Mazurkiewicz-Bełdzińska ,&nbsp;Jakub Szymarek ,&nbsp;Sylwia Studzińska","doi":"10.1016/j.aca.2026.345156","DOIUrl":"10.1016/j.aca.2026.345156","url":null,"abstract":"<div><h3>Background</h3><div>Antisense oligonucleotides are synthetic nucleic acid molecules capable of selectively modulating gene expression. As the number of approved antisense oligonucleotide therapies grows, reliable analytical procedures are needed to monitor their pharmacokinetics, metabolism, and safety. Current solid phase extraction strategies often suffer from limited recovery or poor reproducibility. Methods using non-polar, hydrophilic or anion-exchange sorbents, require application of ion-pair reagents, or high concentration of salts or long conditioning. On the other hand, the potential of sorbents with hydrophobic-hydrophilic properties used for mixed-mode extraction remains unexplored. Our study presents the first application of newly synthesized materials for the isolation of therapeutic antisense oligonucleotides from cerebrospinal fluid samples.</div></div><div><h3>Results</h3><div>Five silica-based sorbents modified with aminopropyl, aliphatic, aromatic, and dicarboxylic groups were designed, synthesized, and characterized. The functionalization of sorbents enables various interactions with oligonucleotides, namely electrostatic, hydrophobic, π … π interactions, and hydrogen bonding. A new, mixed-mode dispersive solid phase extraction procedure was developed using a central composite design, enabling a systematic evaluation of the factors governing antisense oligonucleotide desorption. The effectiveness of the procedure was assessed for oligonucleotides varying in chemical modification and length. Recoveries depended on both factors and were the highest for shortmers with 2′-O-methyl modification. This effect is advantageous for the extraction of antisense oligonucleotide metabolites. The developed method was successfully used for the extraction of antisense oligonucleotides from cerebrospinal fluid, enabling reproducible recoveries (40–93 %). The matrix effects ranged from 89 % to 100 %. The highest recoveries were obtained for an oligonucleotide modified at two structural elements, making the method advantageous for the extraction of oligonucleotides used in therapy.</div></div><div><h3>Significance</h3><div>The proposed mixed-mode dispersive solid-phase extraction procedure provides a simple, fast, and reproducible approach for isolating of antisense oligonucleotides from cerebrospinal fluid. The method significantly simplifies sample preparation, since the procedure may be straightforwardly applied without additional purification steps. These results for the first time demonstrate the suitability and high analytical potential of hydrophobic-hydrophilic sorbents for the extraction of antisense oligonucleotides from biological samples.</div></div>","PeriodicalId":240,"journal":{"name":"Analytica Chimica Acta","volume":"1391 ","pages":"Article 345156"},"PeriodicalIF":6.0,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146048634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}