In a chiral hplc analysis of a racemic drug can one take it for granted that the two enantiomeric peaks represent equal concentration. Suppose I inject 80 ng of the racemic drug can I assume that the each peak (area) represent 40 ng?

Thanks for clarifying.

I would approach it the other way round. With a standard detector, there should be no response difference between both forms. If the area of both peaks in a racemate are not equal, I would declare the racemate to be "impure".