MJ Research PTC-0200, Operation Manual

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DNA Engine & DNA Engine Tetrad Operations Manual
can be solidified at the end of a run. A pipette can then be used to pierce
the wax in the tubes and remove the samples. The wax is dyed red to
assist in monitoring its use. The dye has no adverse effects on fluorescent
gel analysis of reaction products.
Sealing with the Hot Bonnet and Caps or Film Sheets
The Hot Bonnet’s heated inner lid maintains the air in the upper part of
sample vessels at a higher temperature than the reaction mixture. This
prevents condensation of evaporated water vapor onto the vessel walls,
so that solution concentrations are unchanged by thermal cycling. The
Hot Bonnet also exerts pressure on the tops of vessels loaded into the
block, helping to maintain a vapor-tight seal and to firmly seat tubes or
the plate in the block.
Caps, film, or mats must be used along with the Hot Bonnet to prevent
evaporative losses. Tight-fitting caps do the best job of preventing vapor
loss (and should be used for long-term storage of reaction products).
Microseal ‘A’ film is a quick way to seal Multiplate and “Concord”
microplates or large arrays of tubes. This film is specially designed to
seal tightly during cycling yet release smoothly, which minimizes the risk
of aerosol formation and cross-contamination of samples. Microseal ‘A’
is easily cut for use with fewer than 96 wells.
Microseal ‘M’ rubber sealing mats are an economical means to seal 96-
well microplates. An array of 96 dimples on the mat helps orient it on the
microplate and prevents the mat from sticking to the Hot Bonnet’s heated
lid. The mats may be cleaned with sodium hypochlorite for reuse and are
autoclavable.
Note: Note:
Note: Note:
Note: After a hold at below-ambient temperatures, a ring of condensa-
tion may form in tubes above the liquid level but below the top of the
sample block. This is not a cause for concern since it occurs only at the
final cool-down step, when thermal cycling is finished.
Adjusting the Hot Bonnet’s Lid Pressure
The pressure exerted by the inner lid of the Hot Bonnet must be manually
adjusted to fit the sample vessels being used in a given reaction. Once set,
the Hot Bonnet can be opened and closed repeatedly without readjustment
as long as neither the tube or microplate type nor the sealing method
changes. Any change in vessel type or sealing method requires readjust-
ment of the Hot Bonnet’s lid.
Follow these steps to adjust the pressure exerted by the Hot Bonnet’s
inner lid:
1. Make sure the block’s wells are clean. Even tiny amounts of extraneous