ACS Spring 2005 Seminar Omni San Diego Hotel, 675 L Street, San Diego, CA, USA Sunday, March 13, 2005   Poster Schedule   Title:   Accelerating Reversed-Phase Chromatographic Method Development Using Structure-based pKa Prediction Authors:   Scott MacDonald, Michael McBrien, Eduard Kolovanov, Vadim Tashlitsky - ACD/Labs Date:   Sunday, March 13, 2005 from 7:00 PM - 9:00 PM Abstract #:   ANYL 156 Abstract:   Selectivity in high performance liquid chromatography may be tuned by changing the mobile phase pH. Even small changes in mobile phase pH can alter the selectivity by an order of magnitude (or more), which could have a major impact on the robustness of the chromatographic method. Absolute retention times may also be affected by a change in mobile phase pH, which could affect the reproducibility of separations. Therefore, selection of an appropriate mobile phase pH is critical to chromatographic method development when developing stable, reproducible separations. Mobile phase pH levels may be optimized experimentally, but this process can be time consuming. However, prior knowledge of the expected chemical structure(s) and/or functional groups may be used to estimate pKa values, which can then be used to select a range of appropriate mobile phase pH. This paper will describe the practical application of pKa prediction prior to, and during method development. Measurements, databases, and prediction systems are primarily based on aqueous pKa values (predicted or experimental), but reversed-phase chromatography often uses organic solvents. The adaptation of aqueous pKa values to the organic mobile phases will also be discussed.   Title:   Enterprise Level Databasing for Chromatographic Method Development Authors:   Scott MacDonald, Mike McBrien, Margaret Antler - ACD/Labs Date:   Sunday, March 13, 2005 from 7:00 PM - 9:00 PM Abstract #:   ANYL 154 Abstract:   Chromatographic method development can be streamlined a great deal by the use of previous knowledge of samples of similar type. Access to previous results can significantly speed chromatographic method development by pointing to an optimal starting point for similar separations. Unfortunately, previous results are not always easily accessible to the analyst. Enterprise-wide application databasing can accelerate chromatographic method development by providing easy access to previous separations to all chemists within the organization. This poster will describe how a customized, enterprise-wide separations database can accelerate method development. Deployment of the database via thin or thick client installations will be discussed. Accessing results in the database by chemical structure, substructure and text searching will be described. Automated updates of the database using macros and fully automated workflows of the will be demonstrated. The use of external content databases will also be discussed.

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