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Page 17 of 25 SPEX SamplePrep LLC 9.24.07
Accessory Packs can be placed in an insulated container to hold the vials upright during chilling.
At the same time, chill an impactor separately. As soon as the submerged end of the vial is
chilled, drop in the cold sample and then the chilled impactor. (Always wear insulated gloves
when handling chilled vial components directly!) Now carefully insert the other end-plug, still
warm, into the warm end of the cylinder. The vial can now be carefully placed in the mill, or
submerged in a liquid nitrogen bath outside the mill, as long as you are careful not to let the
sample touch the warm end plug before it has cooled down.
Very important: never force an end plug (warm or cold) into a cold polycarbonate cylinder.
Polycarbonate shrinks when chilled, and can crack if stressed. When you follow this procedure
for loading cold samples, if the cylinder has cooled to the point where the end-plug fit is too
tight, warm the end of the cylinder before inserting the end-plug.
6.25 Putting a Very Small Sample in the Vial and Keeping it Cold
A variant of the loading technique in 6.24 can be used to grind very small samples with the open
pre-chilled vial upright. Place the sample on the chilled end-plug and add a small amount of fluid
such as an extraction medium or water. The frozen fluid will bulk up the sample enough so it
will circulate in the vial during grinding. To speed up this process with Small-sized vials like the
6751, some users first prepare small “ice cubes” of the sample frozen together with 0.5 ml to 1
ml of fluid.
6.26 Placing Vials in the Freezer/Mill Coil
Before placing a vial or vials in the 6870 Freezer/Mill, put on cryogenic gloves. Unlatch and lift
the lid of the mill, and open the coil gate. If you are running Small or Mid-Size vials make sure
the proper Adapter is in the coil. Pick up the vial(s) with your gloved hand or an Extractor/Vial
Opener and insert the vial(s) in the coil. Close the coil gate and tighten it against the vials(s) by
turning the gate handle clockwise, but do not overtighten the gate. Lock the gate by folding
down the handle.
If you have additional vials you wish to pre-cool, pick them up the same way and insert them in
the pre-cooling compartment of the coil housing. Check the liquid nitrogen (LN) level and top it
off if necessary. Gently close the Freezer/Mill lid, and latch it. Latch the lid shut. You are now
ready to run a grinding program, as described in Section 5.
6.3 Removing, Opening, Emptying, and Cleaning Freezer/Mill Vials
6.31 Removing Vials from the Freezer/Mill
At the conclusion of the grinding cycle, unlatch the lid and let the gas cylinders lift it. Do not
force the lid, but allow it to rise at its own speed. If the gas cylinders are too worn or chilled to
lift the lid, lift the lid gently.
Remove the vial or vials from the coil, using gloves or an Extractor/Vial Opener. At this point
you may want to shut the lid to conserve LN or insert another vial and begin another grinding
cycle.