Reply to the Comment ``On the thermodynamics of inhomogeneous perfect   fluid mixtures''
  We show that the analysis presented in a recent comment by Coll and Ferrando \cite{comment} (qr-qc/0312058) is based on the erroneous assumption that the chemical potential and fractional concentration of a {\it mixture} of perfect fluids are unknown variables. 
Hernando Quevedo and Ruben D. Zarate