A reminder: wear cryogenic gloves when handling chilled vials.
Remove the vial from the coil, using gloves or the 6754 Extractor. At this point you may want to
shut the lid to conserve liquid nitrogen, or begin another grinding cycle. If the next vial is not
pre-cooled, place it in the coil, shut the lid, confirm that a pre-cooling period is programmed, and
press RUN to begin the grinding cycle. If you are moving a pre-cooled vial into the coil, shut the
lid, program T3 to zero (eliminating the pre-cooling period) and press RUN; grinding will begin
immediately.
To open the vial, slip the open end of the 6754 Extractor over the flanged end-plug, align the
pegs in the end-plug with the slots in the Extractor, and turn the knob clockwise until the end-
plug is drawn out. Always be careful when you do this that the vial does not fall and spill its
contents.
Note: ensure that the extractor is clean and dry, especially the threaded end, before using.
If the extractor sticks when removing a cold end plug, this is probably due to water on the
extractor screw, which freezes when it contacts the end plug. If this happens, make a habit of
wiping off the screw with a paper towel before each use. Note that the end of the screw is tooled
with an “X” cut to help remove any ice that forms on the end plug, but this is not always
effective. Chilled vials can also be opened easily and quickly with the 6814 Auto-Extractor (page
22), an optional accessory for the 6750 and 6850 Freezer/Mills.
Empty the contents of the vial into a suitable container, the quicker the better as condensation on
a cold sample occurs rapidly. Often it is helpful to tap the blunt end of the vial to release the
ground sample. Remember that the impactor may slide out ahead of the contents or with them,
and that the longer the sample is exposed to air, the more water it will acquire by way of
condensation. Samples which were tacky, squishy, etc., at room temperature will also return to
that state as they warm up, and may agglomerate.
The impactor will have to be separated from the sample and can be handled with gloved fingers,
a strong magnet, tongs, or pliers. Tools without a good gripping surface are likely to slip off the
impactor.
If some condensation on a cold sample is unacceptable, you can either wait for the sample vial to
warm up before opening and emptying it, or open and empty a chilled vial in a glove box filled
with dry nitrogen gas.
Small amounts of sample usually adhere to the vial’s impactor, end plugs, and plastic cylinder.
Brushing or scraping these surfaces of the vial can often recover this fraction of the sample.
Again, speed is important to minimize condensation and other effects of warming.
5.0 OPERATION
5.08
Removing, Emptying, and Cleaning the Grinding Vial
(Cont’d)
The 6751 Vial may be cleaned quickly and easily by running hot water over it. If it is cold a
coating of ice can form on the steel parts, but will melt quickly as the water runs. If sample
adheres to the steel parts of the vial, they can be further cleaned with water and soap or
detergent, or even with organic solvents. The steel components can also be autoclaved, but if
they are to be stored they should be carefully dried first. They are made of magnetic stainless
steel, which is corrosion-resistant but will rust if left in contact with water for long periods.
The plastic center cylinder (see page 20) is made of polycarbonate. While this polymer is very
tough at low temperatures, it is sensitive to alcohol and organic solvents, and should be cleaned
only with soap and water. A mild bleach solution will control organic contamination.
Polycarbonate can also be autoclaved, but may be weakened over time by this procedure. While
these cylinders are remarkably durable, always inspect them for cracks before use.
Page 17 of 28
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