Hi Abhishek,

You'll need a vacuum manifold setup: the cheapest / easiest way to do this is to use a standard mechanical vacuum pump and to make your own vacuum manifold out of copper tubing (1/4" works well) and valves (Swagelok). Ideally, you'll want to isolate your Stopcocked NMR tube from the pump in stages so that (initially) you don't open your frozen sample directly to the pump, but rather to a pre-evacuated intermediary stage. After one or two degassing rounds, you may then be able to open the NMR tube directly to the pump. For cooling, chose whichever solution gives you the relevant cooling power (usually liquid nitrogen, or dry ice/acetone slurry). You'll want to use a stopcocked NMR tube (attached using a Swagelok union or Ultratorr), and go through at least 3 rounds of freeze/pump/thaw. Warm the NMR tube between rounds gently using warm water; depending on what is in the tube, it may 'jump' up in the tube upon warming. I've attached a rough schematic (for a single); you can also expand this into multiple 'bays' by adding more valves and places to attach additional NMR tubes. Outside of copper, these can also be made out of stainless steel or blown glass. I'm not sure if any commercial products are on the market (fairly easy to make yourself). The copper tubing can be mounted to a rack, and a lab-jack can be used to slowly raise the level of the coolant (be sure to cool slowly--prevents gases from getting trapped in the solids, and allows aqueous solution time to expand "up" instead of "out"). Best of luck.

Hi Abhishek,

You'll need a vacuum manifold setup: the cheapest / easiest way to do this is to use a standard mechanical vacuum pump and to make your own vacuum manifold out of copper tubing (1/4" works well) and valves (Swagelok). Ideally, you'll want to isolate your Stopcocked NMR tube from the pump in stages so that (initially) you don't open your frozen sample directly to the pump, but rather to a pre-evacuated intermediary stage. After one or two degassing rounds, you may then be able to open the NMR tube directly to the pump. For cooling, chose whichever solution gives you the relevant cooling power (usually liquid nitrogen, or dry ice/acetone slurry). You'll want to use a stopcocked NMR tube (attached using a Swagelok union or Ultratorr), and go through at least 3 rounds of freeze/pump/thaw. Warm the NMR tube between rounds gently using warm water; depending on what is in the tube, it may 'jump' up in the tube upon warming. I've attached a rough schematic (for a single); you can also expand this into multiple 'bays' by adding more valves and places to attach additional NMR tubes. Outside of copper, these can also be made out of stainless steel or blown glass. I'm not sure if any commercial products are on the market (fairly easy to make yourself). The copper tubing can be mounted to a rack, and a lab-jack can be used to slowly raise the level of the coolant (be sure to cool slowly--prevents gases from getting trapped in the solids, and allows aqueous solution time to expand "up" instead of "out"). Best of luck.

Thanks a lot Nicholas. Actually I am using very small dia tube ~2 mm for my DNP experiments. I will try the way you described.