The edge effect of PCR instruments may occur during experiments, which usually means that during the PCR amplification, the reaction of samples near the wall or edge of the tube may be different from the reaction of samples in the center, leading to inconsistency in experimental results. This effect can be caused by a variety of factors, including uneven temperature distribution, different evaporation rates, etc.

Methods to eliminate edge effects of PCR instruments:

1. Optimize the hot cover temperature of the thermal cycler

Hot covers can help reduce sample evaporation during PCR and ensure uniform temperature throughout the PCR tube.

2. Use thermal insulation plates

Placing a thermal insulation plate under a PCR tube or plate can reduce the temperature gradient from the edge to the center of the instrument, thus reducing edge effects.

3. Optimize reaction volume

Working with the instrument's recommended reaction volume can reduce edge effects because the appropriate volume helps transfer heat more evenly.

4. Optimize tube cover or plate cover

Make sure to use appropriate PCR tube covers or plate covers to reduce heat loss and evaporation.

5. Uniformly distribute samples

Distribute samples evenly in the PCR machine and avoid concentrating all samples in one area to reduce local overheating or over-cooling.

6. Preheat the reaction mixture

Preheating the PCR reaction mixture to the initial denaturation temperature before adding template DNA will reduce temperature differences before starting the cycle.

7. Use reagents with stable quality

Using high-quality PCR reagents can improve reaction consistency and reduce edge effects.

8. Regular maintenance and upkeep

Ensure that the PCR machine is regularly maintained, and is used correctly to keep its optimal performance.