Efficient Sequestration and Sensitive Detection of Cd(II) in Food Using a Two-dimensional Imine-linked Covalent Organic Framework: Performance, Modeling, and Mechanism

Efficient Sequestration and Sensitive Detection of Cd(II) in Food Using a Two-dimensional Imine-linked Covalent Organic Framework: Performance, Modeling, and Mechanism | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Efficient Sequestration and Sensitive Detection of Cd(II) in Food Using a Two-dimensional Imine-linked Covalent Organic Framework: Performance, Modeling, and Mechanism Jing Pang, Fangyuhe Meng, Yiyun Song, Hongmei Yu, Guosong Chen, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8696171/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 10 You are reading this latest preprint version Abstract A two-dimensional imine-linked covalent organic framework, named COF-LZU1, was strategically utilized as a high-performance solid-phase extraction (SPE) adsorbent for the ultratrace sequestration of Cd(II) from complex food matrices. Systematic investigations into adsorption kinetics and isotherms revealed that the uptake of Cd(II) follows a pseudo-second-order model and aligns with the Langmuir isotherm, suggesting a monolayer chemisorption process. The maximum theoretical adsorption capacity reached 114.94 mg g − 1 , significantly outperforming many traditional adsorbents. Structural and spectroscopic characterizations (SEM-EDS, BET, FT-IR, and XPS) confirmed that the robust performance of COF-LZU1 originates from its high specific surface area and the abundance of nucleophilic imine linkages (-C = N-) which serve as primary coordination sites. According to the Hard and Soft Acids and Bases principle and DFT simulations, the adsorption mechanism involves a synergistic interplay of electrostatic attraction, chelation, and pore-channel effects. Under optimized conditions, the integrated SPE-GFAAS platform achieved a remarkable limit of detection (3.34 ng L − 1 ) and excellent precision (RSD = 1.0%). The methodology was rigorously validated using various Standard Reference Materials and real food samples, yielding satisfactory recoveries (94.0-104.0%). These findings underscore the immense potential of COFs as specialized scaffolds for the sensitive enrichment and quantification of heavy metals in food safety and environmental monitoring. Covalent organic framework Solid-phase extraction Trace Cd(II) Sensitive detection Food Full Text Additional Declarations No competing interests reported. Supplementary Files Supplementarymaterial.docx Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 04 Mar, 2026 Reviews received at journal 25 Feb, 2026 Reviews received at journal 15 Feb, 2026 Reviewers agreed at journal 10 Feb, 2026 Reviewers agreed at journal 08 Feb, 2026 Reviewers agreed at journal 06 Feb, 2026 Reviewers invited by journal 05 Feb, 2026 Editor assigned by journal 05 Feb, 2026 Submission checks completed at journal 02 Feb, 2026 First submitted to journal 25 Jan, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8696171","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":587617971,"identity":"48291c12-96da-4fca-86fe-033d04e4071e","order_by":0,"name":"Jing Pang","email":"","orcid":"","institution":"University of Science and Technology Liaoning","correspondingAuthor":false,"prefix":"","firstName":"Jing","middleName":"","lastName":"Pang","suffix":""},{"id":587617972,"identity":"754b923b-0b0f-4e47-906f-8e7193423161","order_by":1,"name":"Fangyuhe Meng","email":"","orcid":"","institution":"University of Science and Technology 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Systematic investigations into adsorption kinetics and isotherms revealed that the uptake of Cd(II) follows a pseudo-second-order model and aligns with the Langmuir isotherm, suggesting a monolayer chemisorption process. The maximum theoretical adsorption capacity reached 114.94 mg g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, significantly outperforming many traditional adsorbents. Structural and spectroscopic characterizations (SEM-EDS, BET, FT-IR, and XPS) confirmed that the robust performance of COF-LZU1 originates from its high specific surface area and the abundance of nucleophilic imine linkages (-C\u0026thinsp;=\u0026thinsp;N-) which serve as primary coordination sites. According to the Hard and Soft Acids and Bases principle and DFT simulations, the adsorption mechanism involves a synergistic interplay of electrostatic attraction, chelation, and pore-channel effects. Under optimized conditions, the integrated SPE-GFAAS platform achieved a remarkable limit of detection (3.34 ng L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) and excellent precision (RSD\u0026thinsp;=\u0026thinsp;1.0%). The methodology was rigorously validated using various Standard Reference Materials and real food samples, yielding satisfactory recoveries (94.0-104.0%). 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