FAQ-310
Can Buffers N3 and P3 be used interchangeably?
No. Although both Buffers N3 of the QIAprep Spin Miniprep and P3 of the QIAGEN Plasmid Kits perform the neutralization step in an alkaline lysis procedure, they are completely different. Buffer N3 contains a proprietary formula that sets up binding conditions for the QIAprep Miniprep column's silica-gel-membrane. Buffer P3 sets up binding conditions for QIAGEN anion-exchange columns. Our website explains QIAGEN's nucleic acid purification technologies in more detail.
Related products
QIAprep Spin Miniprep Kit
The QIAprep Spin Miniprep Kit is designed for isolating high-purity plasmid or cosmid DNA, offering up to 20 µg yields for various molecular biology applications like sequencing and cloning. Higher yields (up to 30 µg) can be achieved using the High-Yield Supplementary Protocol. The kit is automatable on the QIAcube Connect.
Want to try the QIAprep Spin Miniprep Kit for the first time? Request a quote for a trial kit.
For optimal results, we recommend pairing this kit with the QIAvac 24 Plus system.
QIAGEN Plasmid Kits
QIAGEN Plasmid Kits provide gravity-flow, anion-exchange tips for purification of transfection-grade plasmid DNA. Lysate clearing and isopropanol precipitation are achieved by centrifugation.
The QIAGEN Plasmid Mega Kit (cat. no. 12181) and the QIAGEN Plasmid Giga Kit (cat. no. 12191) can be used with the QIAfilter Mega-Giga Cartridges (cat. no. 19781) as an optional protocol step for rapid clearing of bacterial lysates by filtration instead of centrifugation. See more information regarding principle below.
QIAfilter Plasmid Kits
QIAfilter Plasmid Kits provide anion-exchange-based plasmid purification with bacterial lysate clearing by filtration. Purified DNA is equivalent to that obtained by 2 x CsCl gradient centrifugation and is suitable for transfection-grade applications.
The QIAfilter Plasmid Mega Kit (cat. no. 12281) and the QIAfilter Plasmid Giga Kit (cat. no. 12291) will be discontinued on June 30, 2021. They remain available as long as stocks last.The QIAGEN Plasmid Mega Kit (cat. no. 12181) and the QIAGEN Plasmid Giga Kit (cat. no. 12191) can be used with the QIAfilter Mega-Giga Cartridges (cat. no. 19781) as an optional protocol step for rapid clearing of bacterial lysates by filtration instead of centrifugation. Visit the QIAGEN plasmid kits web page to learn more.
HiSpeed Plasmid Kits
HiSpeed Plasmid Kits provide fast, large-scale, anion-exchange-based plasmid DNA preparation without centrifugation. The purified DNA is equivalent to that obtained by 2 x CsCl gradient centrifugation and is suitable for transfection-grade applications.
EndoFree Plasmid Kits
EndoFree Plasmid Kits provide anion-exchange-based endotoxin-free plasmid DNA purification. QIAfilter Cartridges enable fast lysate clearing by filtration. The purified DNA exceeds the purity obtained by 2 x CsCl gradient centrifugation and is suitable for advanced transfection-grade applications. The EndoFree Plasmid Buffer Set can be used for preparations of 10 mega or 5 giga transfection-grade plasmid or cosmid DNA preparations.
The Buffer ER in EndoFree Plasmid Kits has been updated to exclude Triton™ X-114, ensuring REACH compliance and even lower endotoxin levels (<0.04 EU/μg) in line with FDA vaccine standards. The improved buffer reduces incubation time from 30 minutes on ice to just 5 minutes at room temperature.*
*Please note: This update includes adjusted Buffer ER volumes and revised incubation times in the protocol.
Plasmid Buffers
Plasmid Buffers are used in plasmid DNA purification procedures. They include Buffer P1 (resuspension buffer), Buffer P2 (lysis buffer), Buffer N3 and Buffer P3 (neutralization buffers), Buffer QC (wash buffer) Buffer QBT (equilibration buffer) and Buffer QF (elution buffer).

