To avoid RNA contamination in your DNA samples when using the new Monarch® Spin Plasmid Miniprep Kit (NEB #T1110), it is important to use RNase A as directed in the protocol. RNase A should be added to the Monarch Buffer B1 (Resuspension buffer, pink) ensuring the correct concentration. Store the buffer at 4°C after adding RNase A.
During the plasmid purification process, at the step where Buffer B3 (neutralization buffer, yellow) is added, ensure the sample is well mixed and allow it to incubate for the recommended amount of time to allow RNA degradation. For bacterial culture volumes exceeding 3 ml, increase the centrifugation time after adding the neutralization buffer to 5 minutes to allow more time for the RNase to digest RNA.