Techne TC-3000G - Manual (Page 36)

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A B C D E F G H
Set
temperature
Highest
temperature
Lowest
temperature
Gradient
TO PROGRAM A GRADIENT
A gradient of temperatures across the block can be useful in optimising the annealing conditions for
primers; a gradient can be set around a temperature in any step of a program. The set temperature is the
temperature required in the middle columns of the block and the gradient is the variation at the two
extremes of the block; the left hand columns being the coolest and the right hand columns the hottest.
The maximum temperature gradient which can be set in the TC-3000G is 15°C; the lowest temperature
is 20°C and the hottest temperature is 80°C. The minimum gradient is 1°C. Examples are given in the
table below:
Lowest temperature Set temperature Highest temperature Gradient
(°C) (°C) (°C) (°C)
20.0 27.5 35.0 15
52.5 60.0 67.5 15
70.0 75.0 80.0 10
52.5 55.0 57.5 5
59.5 60.0 60.5 1
It is important to remember that the greater the gradient, the poorer the uniformity across the block,
therefore fine-tuning may be required to establish the optimum temperature. While the gradient is
mainly linear there are small variations at the extremes of the gradient due to a loss of heat from the
hottest part of the block and a gain of heat from the adjacent column on the coldest. This is the reason
why the first column does not reach the lowest ideal temperature of the gradient and the last column
cannot reach the highest temperature.