chemistry

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1. In standard column chromatography, it is better to change from a nonpolar solvent to more polar solvent. What are some disadvantages if the reverse is done?

2. what would happen if air bubbles were trapped in the adsorbent in column chromatography?


is it loss in resolution?

3. Why does chlorophyll have a smaller Rf value than carotenoid?

  • chemistry -

    1. The main disadvantage is that there is no separation. The material travels straight through the column. Another possibility is that it is possible to contaminate your sample with compounds that are on the stationary phase, small amounts of grease for example.

    2. Yes, loss of resolution is the main problem.

    3. Have a look at the structures of the two

    http://en.wikipedia.org/wiki/Chlorophyll

    There are a number of carotenoid structures here

    http://en.wikipedia.org/wiki/Carotenoid

    The carotenoids are mostly large hydocarbons with a smal number of functional groups such as a single OH, double bonds, aldehyde.

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