Biochemical Techniques and Instrumentation

6.1.4. PCR reaction

The PCR reaction is commonly carried out in a reaction volume of 10–200 μl in small reaction PCR tubes of 0.2–0.5 ml volumes in a thermal cycler. The thermal cycler heats and cools the reaction tubes to achieve the temperatures required at each step of the reaction. Most thermal cyclers make use of the Pletier effect which permits both heating and cooling of the block, holding the PCR tubes, simply by reversing the electric current. Thin-walled PCR tubes permit favorable thermal conductivity to allow rapid thermal equilibration. Most thermal cyclers have heated lids to prevent condensation at the top of the tube.