Dopamine Measurment in PC12

[Federico Corti]

Dear members,

I am measuring Dopamine release from NGF-differentiated PC12. I am using
HPLC with C18 reverse phase column in 10 % methanol isocratic elution.
It seem that after 3-4 times the column get clotted, the pressure go high
and we need to wash a lot with metanol (much more than regular
wash).  Sometimes the injection needle is  blocked and it takes time to
clean it.
Is anyone knows a better way to wash  the  column after meausiring dopamine
from PC12 supernatant?
In my lab. some people measure norepinephrine  from synaptosomes and after
measurment HPLC works well without  problems.

Thanks

Fede