hi

[rajkumarkutani]

In method development, which column is polar,nonpolar c18 or c8. tell me how polarity of a product determined

[DR]

::moved to more appropriate spot::

C18 is a bit less polar than C8. Polarity is a function of the dipole moment of the (active portion of the) stationary phase. For more detail, please see the following:
http://www.lcresources.com/resources/reslinks.html - or, if this is too deep a starting place, look at:
http://www.itsjustabox.com/