When setting the temperature control mode of PCR system, there are generally three options, block, tube and probe. If it is a normal PCR reaction, the tube mode is generally selected. If you want to keep warm for a long time and have high requirements for temperature overshoot, you can use block mode.

Temperature control mode of PCR machine:

The temperature sensor of PCR machine is generally under the module, which means that the instrument can actually control the temperature of the module. Block mode means that the instrument aims to control the temperature of the block. That is to say, if input 95 degrees for 5 minutes, the module will start timing when the temperature reaches 95 degrees, and finish after 5 minutes. This is the basic temperature control mode.

However, actually inputting 95 degrees for 5 minutes is to start timing for 5 minutes after the temperature in the PCR tube reaches 95. You can control the temperature of the module to 97 degrees first, and after a few seconds, wait until the temperature in the tube reaches 95 degrees, and then lower the temperature of the module to 95 degrees. In this way, the temperature in the tube reached 95 degrees at a faster speed. And the overshoot temperature is related to time, the thermal conductivity of the PCR tube, and the volume of the PCR reaction solution. This temperature control method is called tube mode.

If a temperature sensor is directly added to the PCR tube to directly measure the temperature in it, this is the probe mode. That is, put a temperature probe in a tube that does not carry out PCR reaction, and the instrument controls the temperature in the PCR tube according to the temperature measured by the temperature probe.