Hello:
       Here is one way to move small samples of reference gas.
      A simple arrangement in a vacuum line is to secure the sample bottle to
the frame on which the line is built. Attach a short metal line with a valve
at the end, both rated for the pressure in the bottle, of known and small
volume to the outlet valve of the bottle. The second valve is at the end of that
line. (I use Swedgelok fittings.) That is all then attached to the vacuum line.
       In use, with the second valve open vacuum down the line to the outlet
valve of the bottle, close the second valve. Open the bottle outlet valve and
let gas equilibrate in the metal line for a moment. Close the bottle outlet
valve (IMPORTANT)!
       Now you have a small sample, at bottle pressure, of reference gas
ready to carefully bleed into your vacuum line, watching the pressure on a
manometer or gauge.
Best regards,
Martin Cassidy
University of Houston