Is gage r&r what I want???

I would like to figure out the repeatability and reproducability of my
laboratory testing.  I thought I wanted to run a gage r&r study, but
after doing a little bit of reading i'm not so sure.  Hopefully
someone can help me out.

One of the tests that we run is % ammonia.  It involves weighing out a
sample and placing it under an automatic titrator where a known
concentration of acid is titrated into the solution to a set endpoint.
 From what I have read about gage r&r only one instrument is ever used
for the analysis.  In my case there are obviously two (balance and
automatic titrator), both of which may be providing its own error into
the results.

Is there a way to do a gage r&r study on such a procedure or should I
be looking at something else?

Thank you in advance.