Automatised liquid chromatography buffer blending method for log P and weak electrolyte pKa determination

Automatised liquid chromatography buffer blending method for log P and weak electrolyte pKa determination | 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 Automatised liquid chromatography buffer blending method for log P and weak electrolyte pKa determination Tímea Dérerová, Kveta Kalikova This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9278626/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 4 You are reading this latest preprint version Abstract Determination of a compound’s log P and p K a is advantageous in early stages of drug discovery. High pressure liquid chromatography (HPLC) is a viable, high throughput tool that is well-suited for such applications. The advantages stem from the minimal required analyte quantity and the ability to analyse samples of low purity and low water solubility. Determination of log P and p K a via HPLC often utilises reversed phase mode, leveraging the fact that the analyte’s ionisation state affects its hydrophobicity and therefore retention. Estimation of both parameters can be performed under either isocratic or gradient elution, applying linear solvent strength theory. Hereby, we present a novel mobile phase blending method aimed to fully automatise the log P and p K a determination process. The method uses buffer blending by pumps to produce mobile phases in the range of pH 2.5–8.6 within the liquid chromatography system. The results for commonly used classes of drugs show good correlation between experimental log P found in literature and our obtained values. The p K a estimation shows satisfying results in isocratic measurements and solely aqueous mobile phase. The method enables a linear pH gradient generation, likewise applicable for p K a determination. High pressure liquid chromatography Weak electrolytes Acidity Semiempirical calculation Linear solvent strength theory Full Text Supplementary Files Supportingmaterial.docx Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 09 Apr, 2026 Reviewers invited by journal 07 Apr, 2026 Editor assigned by journal 01 Apr, 2026 First submitted to journal 31 Mar, 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. 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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-9278626","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":619112662,"identity":"75343b4d-0ece-4bd7-bd04-3c8cd0e3c6d5","order_by":0,"name":"Tímea Dérerová","email":"","orcid":"","institution":"Univerzita Karlova Přírodovědecká fakulta: Univerzita Karlova Prirodovedecka fakulta","correspondingAuthor":false,"prefix":"","firstName":"Tímea","middleName":"","lastName":"Dérerová","suffix":""},{"id":619112663,"identity":"2e46aa4f-74d2-42eb-a092-c19f545071a3","order_by":1,"name":"Kveta Kalikova","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA50lEQVRIiWNgGAWjYBACCQbmhoMNQAY/QoyxgYAWRogWyQa4UiK0gJUYHCCkFAYk2w82HpxRcVje+Hbz88e8exjkDW43NzD8+INbizRPYsPBDWcOG267c8ywmecZg+GGOwcbGHt4cGuRYwBqediWxrjtRgJQywGGBIMbiQ3MQAfj1sL/EKzFfvOM9I9IWgzwOEwCaMvGNpvEDRI5yLYk4PH+DKAtM87YJM+4kVM4c84BCcOZQC0Hew7g1iJxPvnwx54KCdv+GekbPrw5YCPPdyP94QN8IYZhBJjEY8coGAWjYBSMAmIAAOT9W23mkZ77AAAAAElFTkSuQmCC","orcid":"https://orcid.org/0000-0003-4988-8322","institution":"Univerzita Karlova Prirodovedecka fakulta","correspondingAuthor":true,"prefix":"","firstName":"Kveta","middleName":"","lastName":"Kalikova","suffix":""}],"badges":[],"createdAt":"2026-03-31 10:50:54","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9278626/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9278626/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":106961724,"identity":"99fd552c-89d3-4a5a-984c-c395211febd1","added_by":"auto","created_at":"2026-04-15 09:26:37","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":703671,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9278626/v1_covered_0b9ef0e0-03e1-4df2-9313-6c54adf9ae67.pdf"},{"id":106918002,"identity":"9e1ec3cb-9dd9-4990-94bd-3ef04db55fd8","added_by":"auto","created_at":"2026-04-14 18:48:14","extension":"docx","order_by":10,"title":"","display":"","copyAsset":false,"role":"supplement","size":20970,"visible":true,"origin":"","legend":"","description":"","filename":"Supportingmaterial.docx","url":"https://assets-eu.researchsquare.com/files/rs-9278626/v1/76ff3ff5ed5831b6cf198655.docx"}],"financialInterests":"","formattedTitle":"Automatised liquid chromatography buffer blending method for log P and weak electrolyte pKa determination","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"monatshefte-fur-chemie-chemical-monthly","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"mccm","sideBox":"Learn more about [Monatshefte für Chemie - Chemical Monthly](https://www.springer.com/journal/706)","snPcode":"706","submissionUrl":"https://www.editorialmanager.com/mccm/","title":"Monatshefte für Chemie - Chemical Monthly","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"High pressure liquid chromatography, Weak electrolytes, Acidity, Semiempirical calculation, Linear solvent strength theory","lastPublishedDoi":"10.21203/rs.3.rs-9278626/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9278626/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eDetermination of a compound\u0026rsquo;s log \u003cem\u003eP\u003c/em\u003e and p\u003cem\u003eK\u003c/em\u003e\u003csub\u003ea\u003c/sub\u003e is advantageous in early stages of drug discovery. High pressure liquid chromatography (HPLC) is a viable, high throughput tool that is well-suited for such applications. The advantages stem from the minimal required analyte quantity and the ability to analyse samples of low purity and low water solubility. Determination of log \u003cem\u003eP\u003c/em\u003e and p\u003cem\u003eK\u003c/em\u003e\u003csub\u003ea\u003c/sub\u003e via HPLC often utilises reversed phase mode, leveraging the fact that the analyte\u0026rsquo;s ionisation state affects its hydrophobicity and therefore retention. Estimation of both parameters can be performed under either isocratic or gradient elution, applying linear solvent strength theory. Hereby, we present a novel mobile phase blending method aimed to fully automatise the log \u003cem\u003eP\u003c/em\u003e and \u003cem\u003ep\u003c/em\u003eK\u003csub\u003ea\u003c/sub\u003e determination process. The method uses buffer blending by pumps to produce mobile phases in the range of pH 2.5\u0026ndash;8.6 within the liquid chromatography system. The results for commonly used classes of drugs show good correlation between experimental log \u003cem\u003eP\u003c/em\u003e found in literature and our obtained values. The p\u003cem\u003eK\u003c/em\u003e\u003csub\u003ea\u003c/sub\u003e estimation shows satisfying results in isocratic measurements and solely aqueous mobile phase. The method enables a linear pH gradient generation, likewise applicable for p\u003cem\u003eK\u003c/em\u003e\u003csub\u003ea\u003c/sub\u003e determination.\u003c/p\u003e","manuscriptTitle":"Automatised liquid chromatography buffer blending method for log P and weak electrolyte pKa determination","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-14 18:48:05","doi":"10.21203/rs.3.rs-9278626/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2026-04-09T10:32:41+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-04-07T16:49:40+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-04-01T14:16:03+00:00","index":"","fulltext":""},{"type":"submitted","content":"Monatshefte für Chemie - Chemical Monthly","date":"2026-03-31T08:29:50+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"monatshefte-fur-chemie-chemical-monthly","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"mccm","sideBox":"Learn more about [Monatshefte für Chemie - Chemical Monthly](https://www.springer.com/journal/706)","snPcode":"706","submissionUrl":"https://www.editorialmanager.com/mccm/","title":"Monatshefte für Chemie - Chemical Monthly","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"43d08c28-82a0-499e-bd0c-37563829838a","owner":[],"postedDate":"April 14th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-04-14T18:48:06+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-14 18:48:05","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9278626","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9278626","identity":"rs-9278626","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}