© Thermo Hybaid. Issue 1.0, January 2002
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Advanced Edit – Gradient (optional)
For rapid optimisation of primer annealing parameters the Px2 gradient feature should be used. A
maximum temperature gradient of 15
°
C can be programmed across the 96 well block.
Calibration of your Px2
Every machine is calibrated using miniature thermistor probes located in tubes or attached to
microscope slides. These are placed at several block positions simultaneously, ensuring the required
temperatures and incubation times achieved are identical in all samples.
1.3 The Heated Lid
The heated lid enables the running of temperature cycling protocols without the need for paraffin or
mineral oil overlays. Such vapour barriers are normally required to prevent evaporation before thermal
cycling is complete. This system is designed to be compatible with most reaction sample formats, i.e.
0.5ml, 0.3ml, 0.2ml tubes and 96/384 well plates. In most cases, the experimental protocol is largely
unchanged when switching to an oil-free format.
The heated lid operates by positioning a heated plate in contact with the top of the reaction tubes or
wells. This heated plate then heats the air temperature at the top of each reaction mixture to a
temperature that is permanently higher than the sample temperature. This elevated air temperature,
relative to the sample temperature, minimises evaporation so reducing condensation of the reaction
mixture as it is repeatedly heated and cooled. Condensation on the walls of the reaction vessels below
the level of the block is a feature of block based thermal cyclers. The level of this condensation is very
small and will not affect the reaction in most cases. In very small volume reactions it may however be
necessary to use an oil overlay.
Operating the Lid
Opening the Lid
The lid is opened by turning the knob so that the 'open lid' icon is aligned to the front of the unit (see
Figure 1.1). This releases the catches to raise the lid and expose the block recess.
Closing the Lid
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