You don't say anything about the nature of your analyte but I'm guessing from your use of the term "counter ion" that your analyte is an anion.  If this is indeed the case then you should be easily able to separate the two via anion exchange since dibutyl ammonium ion will be unretained on such a phase.  Alternatively, you could use a cation-exchange phase to remove the dibutyl ammonium ion.

Thank you for the answer. My compound is organic compound with phosphate group attached on it. I need to get rid of this DBAA buffer from my compound before injecting into the mass machine. As you have suggested, I will try cation-exchange resin. 

Cation-exchange phase might be not a good choice for your purpose, since it is your mobile phase buffer. You can either use ammonium acetate instead of dibutyl ammonium acetate as the buffer, which has less effect on your mass machine. Or as Chris said, you can use anion exchange column to separate them easily, if you have to use DBAA