Anuradha,
SLS is fairly straightforward to characterize and quantitate by way of several different methods. You find more about this separation using a column designed for separating surfactants from Dionex at the following link (sodium dodecyl sulfate, the main component in SLS is analyte 6 in the chromatogram):
http://www1.dionex.com/en-us/columns_ac ... 25924.html If you are really working with a mixture rather than a pure compound, you will need to obtain a standard for each of the components (normally there are only four components: the C10, C12, C14 and C16 sulfates and all can be purchased as pure materials from Fluka).