Dissolved Gas Chamber Construction

INTRODUCTION

This protocol outlines the basic construction of dissolved gas chamber bottles, affectionately known as “Shaky Bottles.” These bottles may be used to collect dissolved greenhouse gas samples in the field, which would later be run on a gas chromatograph.

SAFETY

None.

MATERIALS

  • 1 liter polycarbonate bottle
  • Silicone stoppers (size 31D)
  • Rigid CO2-impermeable plastic tubing (5/16” diameter)
    • Suggested: Cole-Parmer, PTFE 3/16” x 5/16” tubing, item #: EW-06605-33
  • Flexible plastic tubing (5/16” and 7/16” diameter)
    • Suggested: Cole-Parmer, PVC, 3/16” x 5/16”, item #EW-96605-02
  • 2 one-way stopcocks (Cole-Parmer: 30600-06)
  • Small zip-ties (8 per bottle)
  • 60 mL syringe
  • Corer or drill press (~17/64” diameter, 0.265 cm)

SHAKY BOTTLE CONSTRUCTION

  1. Cut a piece of rigid tubing that spans the height of the bottle ~12 inches and extends ~1 inch above the mouth of the bottle. Cut a second piece ~2.5-3 inches long.
  2. Use the corer to bore 2 holes (same size as the rigid tubing) next to each other in a silicone stopper. Be careful not to merge the holes together. If using a drill press, be sure to use a drill bit about the diameter of the rigid tubing. If conducting manually, Arni Litt (Schindler lab) has a nice manual borer. You want a snug fit, such that gas collected will not escape during sample collection.
  3. Insert the 3-inch piece of rigid tubing into one of the holes and position it so that there is ~1 inch of tubing above the stopper’s top. You will want the tubing to be flush with the bottom of the stopper. Use a razor blade to cut the tubing at both ends to meet these size requirements.
  4. Insert the long section of tubing into the second hole, such that the tubing touches the bottom of the polycarbonate bottle. Insert two ~1/4” section of the 5/16” flexi tubing over the ridge of the two stopcocks.
  5. Cut two ~3/4” sections of the 7/16” flexi tubing and slip one section over each rigid length of tubing sticking out from the top of the silicone stopper. Insert each stopcock inside the rigid tubing and slide the 7/16” tubing sleeve over the stopcock for a snug fit, then zip-tie tight with two zip-ties at the top and bottom of the 7/16” sections.
  6. Once the shaky bottle is constructed, test the bottle’s ability to retain gas by injecting air into one of the stopcocks using a 60-mL syringe. To do this, begin with both stopcocks closed and fill your syringe with room air. Attach the syringe to one of the stopcocks, open the stopcock, and inject air sample into the bottle. Close your stopcock and remove the syringe. Submerge your chamber in a bucket of water to check for leaks. If there are bubbles, you should check your construction.

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Author: Sydney Clark

Revisions By: Julia Hart

Revisions Date: 9 August 2018