It's not a big problem to leave PCR products at room temperature for one or two days, but this is not a long-term solution. If it's just a temporary one or two hours, don't worry, DNA is very stable and won't degrade.

However, it should be noted that after being left at room temperature for a long time (such as more than 24 hours), the bands may begin to blur, and the risk of degradation will gradually increase. If the ambient temperature is high, degradation will occur faster.

Short term storage (such as within one or two days), stored in a refrigerator at 4 ℃, can effectively inhibit enzyme activity and maintain stability. For long-term storage (several months or even longer), it is standard practice to freeze at -20 ℃ or -80 ℃. If conditions permit, purifying with a specialized reagent kit and then freezing for better results can avoid damage caused by repeated freezing and thawing. If further extension of the storage time of PCR products is required, it is recommended to adopt a strategy of packaging and freezing. Pack the product into multiple sterile EP tubes, with each tube storing a single use amount, to avoid the risk of DNA breakage caused by repeated freeze-thaw cycles. During packaging, it is important to briefly centrifuge the tube opening to prevent contamination caused by residual liquid droplets. For high-value samples, an appropriate amount of glycerol (final concentration of 5% -10%) can be added to the buffer solution. This cryoprotectant can reduce the physical damage caused by ice crystal formation to DNA.

If laboratory conditions are limited, the 'salt ethanol precipitation method' can be used for temporary storage: add 1/10 volume of 3M sodium acetate and 2.5 times the volume of pre cooled anhydrous ethanol, mix and place at -20 ℃. Although this method is not as stable as professional cryopreservation, it can maintain DNA integrity for 1-2 weeks in emergency situations such as power outages. To use, simply centrifuge and discard the supernatant, rinse with 70% ethanol, and resuspend.

It is worth noting that products containing fluorescent labels are sensitive to light and should be stored in light shielded tubes, even at 4 ℃, wrapped in aluminum foil. For samples that require cross-border transportation, it is recommended to use DNA stabilization cards. This specially designed filter paper, the size of a glass slide, can store nucleic acids at room temperature for several months, making it particularly suitable for field sampling scenarios.