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Unformatted text preview: Name Benzene n-Decane n-Heptane n-Hexane n-Octane n-Pentane o-Xylene Structures Boiling Points 80.1 C 174.1 C 98.42 C 69 C 125.52 C 36.1 C 144.4 C Retention times (min) 1.4660 2.8983 1.6022 1.277 2.0105 1.0700 2.4268- The retention time has a positive relationship with the boiling points. Since the stationary phase, methylsilicone based phsed, is non-polar, and all of the components are non-polar, the retention time increases with the increase of boiling point.- The molecule-column interactions are non-polar and non-polar intermolecular attraction. The principal determinant of retention in this case is the volatility of the component. As the column temperature increases, solute with lower boiling point turns into gas sooner than solute with higher boiling point. Therefore, component with lower boiling point is swept along the column by the helium carrier gas more than the component with higher boiling point and was eluted out sooner. On the other hand, solute with higher boiling point stayed in the liquid state component with higher boiling point and was eluted out sooner....
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This note was uploaded on 02/11/2012 for the course CHEMISTRY 15 taught by Professor Bordel during the Fall '11 term at University of California, Berkeley.
- Fall '11