QIAGEN Plasmid Plus Midi Kit (100)

The kit from QIAGEN is intended for purifying plasmid DNA from bacterial cultures. According to the protocol documentation, it can be stored at room temperature for up to 24 months and requires the addition of RNase A and ethanol before use. The workflow covers harvesting bacterial cultures, preparing lysates, and purifying plasmid DNA using specific buffers and centrifugation, with optional use of LyseBlue reagent.

The protocol accommodates standard sample volumes of 20–25 ml or 50 ml. Lysate preparation involves adding Buffer P2, gently mixing by inverting, and incubating at room temperature (15–25°C) for 3 min, followed by the addition of Buffer S3 and filtration through a QIAfilter Cartridge. The cleared lysate is mixed with Buffer BB and processed through QIAGEN Plasmid Plus spin columns placed on a QIAvac 24 Plus under approximately –300 mbar vacuum. Wash steps use 0.7 ml Buffer ETR and 0.7 ml Buffer PE. Residual wash buffer is removed by centrifugation at 10,000 x g (9,700 rpm) for 1 min in a tabletop microcentrifuge. DNA is eluted by adding 200 µl Buffer EB or water to the centre of the spin column, letting it stand for ≥1 min, and centrifuging for 1 min.

Further assistance is available through the QIAGEN Plasmid Plus Purification Handbook and Safety Data Sheets online.