Analytica Chimica Acta最新文献

{"title":"T4 DNA ligase-mediated RAA coupled with RNA aptamer-driven cascade signal amplification for ultra-sensitive monkeypox virus detection","authors":"Chenxi Li ,&nbsp;He Sun ,&nbsp;QingWen Jia ,&nbsp;Zebin Zhang ,&nbsp;Shengjun Bu ,&nbsp;Hongtao Zhou ,&nbsp;Longtao Wang ,&nbsp;Jiayu Wan","doi":"10.1016/j.aca.2026.345116","DOIUrl":"10.1016/j.aca.2026.345116","url":null,"abstract":"<div><h3>Background</h3><div>The global dissemination of monkeypox virus (MPXV) poses a formidable challenge to public health systems worldwide, disrupting surveillance and containment strategies. This crisis underscores the urgent demand for rapid diagnostic technologies that balance high sensitivity for detecting low viral loads and strict specificity to prevent cross-reactivity. To address this unmet need, the present study developed a cascade signal amplification system—named “Monkeypox Fluorescent T4-Ligase Assay (MFTA)”—by integrating recombinase-aided amplification (RAA) and fluorescent RNA aptamer sensing technology, with T4 DNA ligase as the core mediator.</div></div><div><h3>Results</h3><div>MFTA generates single-stranded DNA (ssDNA) templates through 5′-phosphorylated primers combined with Lambda nuclease treatment and employs two specifically designed bifunctional probes: Probe-L, which incorporates a T7 promoter, and Probe-R, which contains a DNA Mango aptamer sequence. In the presence of MPXV, T4 DNA ligase specifically catalyzes probe ligation to form a complete transcription template, further initiating T7 RNA polymerase-mediated in vitro transcription. This process produces abundant RNA Mango aptamers, which specifically bind the TO1 fluorophore to generate a detectable fluorescent signal. The “Identification-Ligation-Transcription-Fluorescence” cascade enables dual verification: RAA ensures target-specific amplification of MPXV sequences, while T4 DNA ligase guarantees precise probe ligation and reduces non-specific background noise. Experiments confirmed MFTA has a detection limit of 1 copy/μL for MPXV, with results consistent with those of qPCR, and effectively discriminates MPXV from other orthopoxviruses.</div></div><div><h3>Significance</h3><div>MFTA innovatively integrates the precise specific recognition of target sequences by T4 DNA ligase with the efficient signal amplification capability of RNA aptamers, successfully establishing a novel technical platform for pathogen detection. Its high sensitivity, strong specificity, and favorable scalability make it a valuable tool for MPXV diagnostics, supporting targeted public health responses to outbreaks and aiding in curbing virus spread.</div></div>","PeriodicalId":240,"journal":{"name":"Analytica Chimica Acta","volume":"1389 ","pages":"Article 345116"},"PeriodicalIF":6.0,"publicationDate":"2026-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995961","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 high-throughput detection platform for dried blood spots constructed with DESI-MS/MS","authors":"Siqi Gao ,&nbsp;Jinhui Zhao ,&nbsp;Yue Guan ,&nbsp;Liyan Liu","doi":"10.1016/j.aca.2026.345109","DOIUrl":"10.1016/j.aca.2026.345109","url":null,"abstract":"<div><h3>Background</h3><div>Dried blood spot (DBS) technology, as a method of blood collection and preservation, has the advantages of small blood collection, convenient transportation and avoiding the degradation of metabolites. In particular, it has broad clinical application prospects in newborn screening and therapeutic drug monitoring. Desorption electrospray mass spectrometry (DESI-MS) is a simple, rapid and in situ spatial metabolomics detection technique, but its throughput, accuracy and coverage for DBS remain to be investigated compared with traditional methods.</div></div><div><h3>Results</h3><div>In the UPLC-MS/MS platform, the optimal extraction solvent, extraction solvent volume and extraction method were ACN: H₂O (v:v/3:1), 300 μL and ultrasonic extraction, respectively. Based on the DESI-MS/MS platform, the best spray solvent was MeOH: H₂O (v:v/3:1), the spray velocity was set at 2 μL/min, the spray needle angle was set at 55°, and the capillary voltage was set at 4.5 kv (DESI⁺), respectively. The approach delivered consistent data assurance, broad metabolite coverage, and acceptable reproducibility. Finally, these methods were applied to detect the metabolic profiles of subjects before and after drinking sugar-sweetened soy milk, and the metabolic map was well isolated, and the difference metabolites were successfully found.</div></div><div><h3>Significance</h3><div>Two protocols of metabolic profiles for DBS were constructed and optimized. The good performance of DESI-MS/MS was obtained when comparing to the UPLC-MS/MS. The application of sweetened soy milk showed that the two protocols developed have the practicability of detecting differential changes in metabolic profiles of DBS.</div></div>","PeriodicalId":240,"journal":{"name":"Analytica Chimica Acta","volume":"1390 ","pages":"Article 345109"},"PeriodicalIF":6.0,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995957","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 comprehensive soil pollution monitoring system based on convolutional recursive sequence network and terahertz spectroscopy","authors":"Ao Feng ,&nbsp;Lijia Xu ,&nbsp;Yuchao Wang,&nbsp;Zhijun Wu","doi":"10.1016/j.aca.2026.345117","DOIUrl":"10.1016/j.aca.2026.345117","url":null,"abstract":"<div><h3>Background</h3><div>Accurate analysis of the total amount of heavy metals and their distribution patterns in soil can aid in determining the extent of soil pollution and iake appropriate remediation measures.Traditional detection methods are inefficient, and standard machine learning approaches are insufficiently sensitive in detecting the range when dealing with several contaminants of heavy metals. In this study, the contents of three heavy metals, cadmium (Cd), nickel (Ni), and zinc (Zn), in soils of different pollution types and concentrations were detected through terahertz spectral curve analysis.</div></div><div><h3>Results</h3><div>A convolutional recursive sequence network (CRST) with cascaded convolutional kernel and cyclic sequence structure was designed to further improve the soil heavy metal detection accuracy by capturing and integrating the sequence dependencies in the continuous terahertz bands. We compared common machine learning models with feature extraction algorithms, and the experimental results show that the CRST method can accurately identify soil heavy metal contamination species under the combined model of all data. The CARS-CRST combination achieved a classification accuracy of 99.54 % when the soil was contaminated with a single heavy metal. The CARS-CRST combination achieved a classification accuracy of 95.26 % when the soil was contaminated with a mixture of heavy metals. The CRST method can also accurately determine the heavy metal content in soil for Cd, Ni, and Zn, achieving optimal R² and RMSE values when the prediction model is constructed for these elements.</div></div><div><h3>Significance</h3><div>Based on terahertz spectroscopy and machine learning technology, this study conducted both qualitative and quantitative research on soil heavy metals, providing robust technical support for the scientific management and precise monitoring of soil.The results show that terahertz technology and machine learning technology can bring new ideas and prospects for soil pollution detection.</div></div>","PeriodicalId":240,"journal":{"name":"Analytica Chimica Acta","volume":"1389 ","pages":"Article 345117"},"PeriodicalIF":6.0,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145993140","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":"Highly sensitive chemiluminescence immunoassay utilizing functionalized magnetic metal-organic framework materials for the detection of CEA and CA199","authors":"Xiaomin Zuo ,&nbsp;Wenxia Chen ,&nbsp;Xianlong Lu ,&nbsp;Rui Yuan ,&nbsp;Shuangyi Hu ,&nbsp;Yangyang Xue ,&nbsp;Wei Chen ,&nbsp;Rui Yang","doi":"10.1016/j.aca.2026.345114","DOIUrl":"10.1016/j.aca.2026.345114","url":null,"abstract":"<div><h3>Background</h3><div>In response to the urgent need for highly sensitive and rapid combined detection of multiple tumor markers for the early diagnosis of colorectal cancer, this work innovatively constructs a magnetically-driven chemiluminescence (CL) immunosensing platform (CoFe₂O₄@ZIF-8/luminol-Au NPs).</div></div><div><h3>Results</h3><div>CoFe₂O₄ NPs were firstly aminated via solvothermal method and lysine modification to provide specific binding sites. ZIF-8 was then grown in situ to form a core-shell structure with high specific surface area for efficient luminol loading. Finally, Au NPs were generated in situ within ZIF-8, simultaneously immobilizing luminol to form composite signal units. This design integrates magnetic separation, confinement effects, and signal amplification, generating an ideal microenvironment for enhanced CL reactions. The label-free CL immunoassay achieves an impressive limit of detection (LOD) of 22 fg/mL for CEA and 5.4 fg/mL for CA199, with broad linear ranges spanning over 5 orders of magnitude. The entire detection process is completed within 30 min, and the analysis of real serum samples demonstrates good recoveries.</div></div>","PeriodicalId":240,"journal":{"name":"Analytica Chimica Acta","volume":"1389 ","pages":"Article 345114"},"PeriodicalIF":6.0,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995955","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":"Specific lysine guanidination and long alkyl chain tagging-assisted negative enrichment strategy enables comprehensive profiling of protein N-terminal acetylome","authors":"Yang Li ,&nbsp;Yu He ,&nbsp;Weijie Zhang ,&nbsp;Mengqing Yang ,&nbsp;Wei Yu ,&nbsp;Zhenbin Zhang","doi":"10.1016/j.aca.2026.345112","DOIUrl":"10.1016/j.aca.2026.345112","url":null,"abstract":"<div><h3>Background</h3><div>Protein N-terminal acetylation (Nt-acetylation) is a widespread and essential modification in both eukaryotes and prokaryotes. To achieve in-depth profiling of Nt-acetylome, enrichment of Nt-acetylated peptides prior to mass spectrometry (MS) analysis is crucial, as their inherently low ionization efficiency is further suppressed in complex peptide mixtures. However, current methods are constrained by low enrichment selectivity and insufficient proteolytic digestion efficiency toward Nt-acetylated peptides.</div></div><div><h3>Results</h3><div>Herein, we present a novel and effective enrichment method involving the specific blocking of lysine ε-amino groups by guanidination and long alkyl chain tagging to N-terminal/internal peptides with free α-amino groups. Due to their enhanced hydrophobicity, the alkylated N-terminal/internal peptides could be efficiently depleted via a C18 column, thus achieving the negative enrichment of Nt-acetylated peptides. Specific guanidination of lysine residues ensures high enrichment selectivity and efficient tryptic digestion of Nt-acetylated peptides. In a single-shot analysis of HeLa cells, our method yielded a significant 4-fold increase in the identification number of Nt-acetylated peptides compared to direct analysis. When coupled with high-pH C18 fractionation, this approach identified 4957 unique Nt-acetylated peptides, corresponding to 3042 acetylated N-termini and 902 putatively neo-acetylated N-termini, markedly expanding the identification coverage of current Nt-acetylation dataset. Furthermore, this method was successfully applied to the quantification of N-terminal acetylome in hippocampal tissues from Alzheimer's disease (AD) mice modeled by amyloid-beta (Aβ) hippocampal injection.</div></div><div><h3>Significance</h3><div>Our method exhibits high enrichment selectivity, efficient proteolytic efficiency and minimal bias toward Nt-acetylated peptides in complex samples. This robust and versatile strategy offers an efficient alternative for comprehensive profiling of Nt-acetylome, thereby facilitating deeper insights into the physiological and pathological functions of Nt-acetylation across diverse biological systems.</div></div>","PeriodicalId":240,"journal":{"name":"Analytica Chimica Acta","volume":"1388 ","pages":"Article 345112"},"PeriodicalIF":6.0,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145972580","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":"On-exosome-membrane DNA polymerization-powered magneto-electrochemical aptasensing for osteosarcoma","authors":"Guang-Xian Zhong ,&nbsp;Huang-Feng Lin ,&nbsp;Fei-Huan Fu ,&nbsp;Jing-Wei Zhou ,&nbsp;Chong-Yu Chen ,&nbsp;Chao-Yang Wu ,&nbsp;Jian-Ping Lin ,&nbsp;Xiong-Wei Xu ,&nbsp;Jian-Hua Lin ,&nbsp;Jin-Yuan Chen","doi":"10.1016/j.aca.2026.345093","DOIUrl":"10.1016/j.aca.2026.345093","url":null,"abstract":"<div><h3>Background</h3><div>The development of exosomes-based non-invasive liquid biopsy method is essential for an early diagnosis of cancers such as osteosarcoma (OS). The emerging isothermal nucleic acid amplification (NAA)-integrated electrochemical aptasensor (E-aptasensor) holds a great promise due to its affordability, rapid response, high sensitivity, and multiplexing capability. However, these aptasensors often require a challenging and complicated integration of signal trigger sequences into the parent aptamers that regulates the NAA. Thus, it is highly desirable to develop a template-free and universal isothermal NAA-intergrated E-aptasensor for OS-derived exosome detection.</div></div><div><h3>Results</h3><div>Herein, via terminal deoxynucleotidyl transferase (TdTase)-mediated DNA polymerization on exosome membrane, we firstly proposed a membrane-initiated enzymatic polymerization (MIEP)-based magneto-driven E-aptasensor for an ultrasensitive detection of OS cell-derived exosomes. Specifically, the LC09 aptamers-modified magnetic microbeads (MMBs) efficiently captured the specific exosomes. Afterwards, the direct on-exosome membrane DNA polymerization was performed by TdTase and then large amounts of horseradish peroxidases were bound via immunoreaction, leading to a strong catalytic current in the substrate of 3,3′,5,5′-tetramethylbenzidine/hydrogen peroxide on the surface of a magnetic glassy carbon electrode. This MIEP-based E-aptasensor reported a satisfactory detection result, displaying a broad linear range (6 × 10⁷∼6 × 10¹⁰ particles/mL), a low detection limit (60 particles/μL), a good specificity toward other tumor cell-derived exosomes, and a good recovery (87.9 %–98.3 % in human plasma). Finally, this method was applied to different clinical samples of micro-volume plasma and distinguished them successfully.</div></div><div><h3>Significance</h3><div>The proposed aptasensor can serve as a powerful and potential tool for liquid biopsy of OS, owing to its high generality, low sample demand, and high practicability. Furthermore, the innovative design strategy established in this work provides a new and versatile avenue for the construction of advanced exosome biosensors, thereby broadening their application in clinical research and precision medicine.</div></div>","PeriodicalId":240,"journal":{"name":"Analytica Chimica Acta","volume":"1390 ","pages":"Article 345093"},"PeriodicalIF":6.0,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145993296","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 novel pyrazine-based Eu-MOFs AIECL immunosensor with antenna effect and Au@Sn3O4 as co-reaction accelerator for ultrasensitive detection of deoxynivalenol","authors":"Jiayuan Nie ,&nbsp;Jing Shi ,&nbsp;Chunyan He ,&nbsp;Huiling Jiang ,&nbsp;Kang Wu ,&nbsp;Anping Deng ,&nbsp;Xinjian Feng ,&nbsp;Jianguo Li","doi":"10.1016/j.aca.2026.345115","DOIUrl":"10.1016/j.aca.2026.345115","url":null,"abstract":"<div><h3>Background</h3><div>Deoxynivalenol (DON), a widespread mycotoxin produced by Fusarium fungi, contaminates grains like wheat and corn, its thermal/chemical resistance prevents full decomposition during food processing. The severe toxicological impacts of DON have instigated scientific vigilance and elevated public apprehension. The International Agency for Research on Cancer (IARC) assigned deoxynivalenol to its Group 3 classification within its chemical carcinogen taxonomy in 2017. Therefore, it is crucial to detect the content of DON contaminants in grains. In this paper we developed a novel electrochemical luminescence immunoassay based on pyrazine ligands for the detection of DON in grains.</div></div><div><h3>Results</h3><div>This work presents a significant conceptual and methodological advancement in the field of electrochemiluminescence biosensing. The synthesized Eu-MOF, utilizing 2,3,5,6-tetrakis(4-carboxyphenyl) pyrazine as an AIE (aggregation-induced electrochemiluminescence) ligand and Eu³⁺ as the metal center, exhibited a significantly enhanced and stable ECL emission compared to the ligand alone, which is attributed to the effective \"antenna effect\". When integrated with Au@Sn₃O₄ nanoflowers as a co-reaction accelerator, the ECL intensity was further amplified due to improved electron transfer and catalytic efficiency. After optimizing all parameters, the optimal experimental conditions were determined. The constructed immunosensor demonstrated an excellent wide-range linear response to DON concentrations from 0.007 ng mL⁻¹ to 1000 ng mL⁻¹, with an ultra-low detection limit of 2.3 pg mL⁻¹ (S/N = 3). The sensor also showed high selectivity against other common mycotoxins and satisfactory stability.</div></div><div><h3>Significance</h3><div>The successful implementation of this \"AIE-antenna\" dual-effect strategy provides a new and general paradigm for designing high-performance ECL materials. Furthermore, the constructed immunosensor demonstrates its practical utility for the ultrasensitive monitoring of mycotoxins in food safety. The outstanding analytical performance, as evidenced by the ultra-low detection limit, underscores the reliability of this platform and its great potential for the detection of various trace-level contaminants in complex sample.</div></div>","PeriodicalId":240,"journal":{"name":"Analytica Chimica Acta","volume":"1389 ","pages":"Article 345115"},"PeriodicalIF":6.0,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995962","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":"Smartphone-integrated colorimetric and ratiometric fluorescence sensor for visual detection of HSO4−","authors":"Yu Ding ,&nbsp;Guoxing Zhang ,&nbsp;Lishan Chen ,&nbsp;Shengwen Yang ,&nbsp;Ning Liu ,&nbsp;Hao Zhang","doi":"10.1016/j.aca.2026.345118","DOIUrl":"10.1016/j.aca.2026.345118","url":null,"abstract":"<div><h3>Background</h3><div>The detection of bisulfate (HSO₄⁻) is critical in food preservation and pharmaceutical quality control, as it is a common additive with potential health risks. Existing detection methods often lack the portability for on-site analysis or the capability for cross-validation to ensure accuracy. Establishing a rapid and reliable quantitative method for HSO₄⁻ is the prerequisite and core step for precisely controlling related food and pharmaceutical additives.</div></div><div><h3>Results</h3><div>To address the need for a rapid, reliable, and field-deployable sensing platform that provides intuitive visual feedback and quantitative data for HSO₄⁻ detection in complex real-world samples, we engineered a novel Schiff base probe (<strong>KF</strong>) integrating aggregation-induced emission (AIE), excited-state intramolecular proton transfer (ESIPT), and intramolecular charge transfer (ICT) properties. HSO₄⁻ triggers a specific cleavage of the probe's imine bond, inducing a distinct colorimetric change (yellow to colorless) and a ratiometric fluorescence shift (yellow-green to blue). This dual-signal response enables visual qualitative analysis and provides an internal reference for quantitative measurement, with a fluorescence detection limit down to 72.9 nM. We integrated the probe with a smartphone-based RGB analysis platform (ColorPicker App), creating a portable device for on-site, quantitative determination. The platform's efficacy was successfully demonstrated by accurately detecting HSO₄⁻ in spiked vegetable and pharmaceutical samples with satisfactory recovery rates (83.1 %–114.4 %).</div></div><div><h3>Significance</h3><div>This work presents the first multifunctional probe combining AIE, ESIPT, and ICT for HSO₄⁻-triggered cleavage, enabling a dual-mode response. This study is significant for establishing a robust, smartphone-integrated sensor that transcends laboratory confines, offering a practical solution for on-site monitoring in food safety and pharmaceutical analysis.</div></div>","PeriodicalId":240,"journal":{"name":"Analytica Chimica Acta","volume":"1389 ","pages":"Article 345118"},"PeriodicalIF":6.0,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995954","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":"Implications of specific ion effects on salt-induced proteome precipitation in organic solvent","authors":"Ziheng Dang,&nbsp;Jessica L. Nickerson ,&nbsp;Alan A. Doucette","doi":"10.1016/j.aca.2026.345111","DOIUrl":"10.1016/j.aca.2026.345111","url":null,"abstract":"<div><h3>Background</h3><div>Solvent-based protein precipitation is an integral component of the proteomics workflow, as a means of concentrating and purifying proteins ahead of digestion and mass spectrometry. We previously disclosed the critical importance of ionic species above a minimal concentration to maximize protein precipitation in 80 % acetone; however, the type of salt was not varied. Specific ion effects have been examined for decades, with many exceptions to the classic Hofmeister series reported. Specifically, the relative influence of various salts has been ranked for their capacity to enhance or reverse protein solubility, but the relevance in proteome sample preparation has yet to be characterized.</div></div><div><h3>Results</h3><div>We hereby demonstrate that specific ion effects have a controlling influence on modulating protein aggregation efficiency in 80 % acetone. Distinct salts facilitate aggregation of proteins from a proteomic mixture to varying degrees in organic solvent. Moreover, we reveal a salt-specific systematic precipitation efficiency bias correlating to intrinsic protein properties. Sodium salts of chloride and sulfate were shown to strongly correlate with the protein's molecular weight and degree of aromaticity, with higher MW and aromaticity enhancing aggregation. Zinc salts of chloride and sulfate, on the other hand favored aggregation of low MW proteins. Proteins with a higher fraction of basic amino acids also showed higher precipitation efficiency for zinc salts, while higher histidine content favored precipitation with ZnCl₂ but not with ZnSO₄.</div></div><div><h3>Significance</h3><div>These results point to a combination of protein-ion, protein-solvent, and ion-solvent interactions influencing their solubility in organic solvent, with differing mechanisms of precipitation being strongly salt dependent, and provide a greater understanding of salt-mediated protein precipitation in organic solvent.</div></div>","PeriodicalId":240,"journal":{"name":"Analytica Chimica Acta","volume":"1390 ","pages":"Article 345111"},"PeriodicalIF":6.0,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145968468","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 covalent conjugation enrichment strategy for analysis of dimethyllysine sites in the proteome","authors":"Lufeng Yan ,&nbsp;Manqian Zheng ,&nbsp;Mingxuan Wu","doi":"10.1016/j.aca.2026.345108","DOIUrl":"10.1016/j.aca.2026.345108","url":null,"abstract":"<div><div>Lysine methylation is a common protein post-translational modification, and it has three forms as monomethyllysine (Kme1), dimethyllysine (Kme2) and trimethyllysine (Kme3). All of them have exhibited significant roles in many biological processes. Thus, development of methods for analysis of methyllysine sites is essential to further explore their biological functions. In a previous study, we found that covalent conjugation enrichment strategy has exhibited much more significant advantages in the analysis of cellular Kme1 sites than affinity-based or strong cation-exchange method. It encouraged us to develop a covalent conjugation enrichment strategy for deep exploration of Kme2 sites in the proteome. Here, we reported a Kme2 enrichment strategy including transforming Kme2 peptides into Kme1 peptides and using an aryl diazonium resin to enrich those newly produced Kme1 peptides. First, Kme2 peptides could be efficiently converted into Kme1 peptides through two steps including oxidization and elimination, and the only significant and complete side reaction on 20 natural amino acids is the oxidation on methionine. Meanwhile, propionylation could be utilized to block the original Kme1 residues for distinction with new produced ones. By this strategy, we could enrich Kme2 peptides in a complex mixture of peptides and finally identify 32 common Kme2 sites in HeLa cells by three replicates. 24 of them were unreported according to PhosphoSitePlus and 8 of them were known, including K561me2 of heat shock 70 kDa protein (HSP70), K55me2 and K165me2 of elongation factor 1-alpha 1 (EF1A1). Kme2 is an intermediate state of lysine methylation and plays significant roles in various biological processes especially on epigenetic regulation. Identification on Kme2 sites is basic for further understanding of their biological significance for both histone and nonhistone proteins. Our covalent conjugation enrichment strategy realized broad analysis of Kme2 sites in the proteome and provided great potential for exploring significant biological functions of Kme2 sites.</div></div>","PeriodicalId":240,"journal":{"name":"Analytica Chimica Acta","volume":"1388 ","pages":"Article 345108"},"PeriodicalIF":6.0,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145968469","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}