QIAquick PCR Purification Kit
For purification of up to 10 μg PCR products, 100 bp to 10 kb
- Up to 95% recovery of ready-to-use DNA
- Cleanup of DNA up to 10 kb in three easy steps
- Gel loading dye for convenient sample analysis
Cat. No. / ID: 28104
The QIAquick PCR Purification Kit provides spin columns, buffers, and collection tubes for silica-membrane-based purification of PCR products >100 bp. DNA of up to 10 kb is purified using a simple and fast bind-wash-elute procedure and an elution volume of 30–50 μl. An optional pH indicator allows easy determination of the optimal pH for DNA binding to the spin column. The procedure can be fully automated on the QIAcube Connect.
For optimal results it is recommended to use this product together with QIAvac 24 Plus.
QIAquick Kits contain a silica membrane assembly for binding of DNA in high-salt buffer and elution with low-salt buffer or water. The purification procedure removes primers, nucleotides, enzymes, mineral oil, salts, agarose, ethidium bromide, and other impurities from DNA samples (see figure " Complete primer removal after PCR"). Silica-membrane technology eliminates the problems and inconvenience associated with loose resins and slurries. Specialized binding buffers are optimized for specific applications and promote selective adsorption of DNA molecules within particular size ranges.
To enable faster and more convenient sample processing and analysis, gel loading dye is provided. GelPilot Loading Dye contains three tracking dyes (xylene cyanol, bromophenol blue, and orange G) to facilitate the optimization of agarose gel run time and prevent smaller DNA fragments migrating too far (see figure " GelPilot Loading Dye").
The QIAquick system uses a simple bind-wash-elute procedure (see flowchart " QIAquick and MinElute procedure"). Binding buffer is added directly to the PCR sample or other enzymatic reaction, and the mixture is applied to the QIAquick spin column. The binding buffer contains a pH indicator, allowing easy determination of the optimal pH for DNA binding (see figure "pH Indicator Dye"). Nucleic acids adsorb to the silica membrane in the high-salt conditions provided by the buffer. Impurities are washed away and pure DNA is eluted with a small volume of low-salt buffer provided or water, ready to use in all subsequent applications.
QIAquick spin columns are designed to provide two convenient handling options. The spin columns fit into a conventional table-top microcentrifuge or onto any vacuum manifold with luer connectors, such as QIAvac 24 Plus with QIAvac Luer Adapters. The QIAquick PCR Purification Kit, in addition to other QIAGEN spin-column-based kits, can be fully automated on the QIAcube, enabling increased productivity and standardization of results (see figures "Spin column handling options A, B, C, D, and E").
DNA fragments purified with the QIAquick system are ready for direct use in all applications, including sequencing, microarray analysis, ligation and transformation, restriction digestion, labeling, microinjection, PCR, and in vitro transcription.
|Binding capacity||10 µg|
|Sample type: applications||ssDNA or dsDNA from PCR and other enzymatic reactions|
|Fragments removed||< 40mers|
|Elution volume||> 30 µl|
|Fragment size||100 bp – 10 kb|
|Type(s) of DNA recovered||ss DNA and dsDNA|
Larger DNA fragments bind more tightly to the QIAquick columns. It is difficult to predict whether a DNA fragment larger than 10 kb can be efficiently recovered, because this depends on base composition as well as fragment size. If the fragment is only a few kb larger than the 10 kb limit, it can be helpful to heat the elution buffer EB to 60°C and let it incubate on the column for a few minutes before centrifuging. However, please note that it will become less likely to recover your sample the larger the fragment size is. As we cannot guarantee recovery of fragments larger than the maximum cutoff size, we do not recommend to purify such fragments using QIAquick Kits.
The QIAEX II Kit can be used to extract DNA fragments up to 50 kb from agarose or polyacrylamide gels.
Buffer PB of the QIAquick PCR Purification Kit cannot be used to extract DNA from agarose gels. However, Buffer QG of the QIAquick Gel Extraction Kit can be used to remove salt and proteins from enzymatic reactions by adding 3 volumes of Buffer QG and 1 volume of isopropanol to the reaction and proceeding with step 6 of the Gel Extraction Spin Protocol in the QIAquick Spin Handbook. See the QIAquick Spin Handbook for a list of reactions which can be cleaned up with the various QIAquick kits.
Buffer PE did not contain ethanol
Ethanol must be added to Buffer PE (concentrate) before use. Repeat procedure with correctly prepared Buffer PE.
Inappropriate elution buffer
DNA will only be eluted efficiently in the presence of low-salt buffer (e.g., Buffer EB: 10 mM Tris·Cl, pH 8.5) or water. Elution efficiency is strongly dependent on the salt concentration and pH of the elution buffer. Contrary to adsorption, elution is most efficient under basic conditions and low salt concentrations. DNA is eluted with 50 or 30 µl of the provided Buffer EB (10 mM Tris·Cl, pH 8.5), or water. The maximum elution efficiency is achieved between pH 7.0 and 8.5. When using water to elute, make sure that the pH is within this range. In addition, DNA must be stored at –20°C when eluted with water since DNA may degrade in the absence of a buffering agent. Elution with TE (10 mM Tris·Cl, 1 mM EDTA, pH 8.0) is possible, but not recommended because EDTA may inhibit subsequent enzymatic reactions.
Elution buffer incorrectly dispensed
Add elution buffer to the center of the QIAquick membrane to ensure that the buffer completely covers the membrane. This is particularly important when using small elution volumes (30 µl).
Based on our experience, the QIAquick PCR Purification Kit removes SYBR Green dye efficiently from PCR reactions.
We strongly assume that the QIAquick Gel Extraction Kit will be equally efficient in removing this dye, however, we recommend a 5 min incubation with wash Buffer PE on the QIAquick spin column at step 10 of the QIAquick Gel Extraction Kit Protocol. Efficiency of SYBR Green dye removal has to be validated by the enduser.
Yes. The QIAquick PCR Purification Kit has been used to clean up fragments between 100 bp and 10 kb from a wide range of enzymatic reactions, removing salts, buffers, enzymes, nucleotides, and primers smaller than 40 nucleotides. Reactions that can be cleaned up with the QIAquick PCR Purification Kit include restriction digests, random priming, ligase, kinase, phosphatase, nuclease, nick translation, and cDNA synthesis reactions.
For data and additional information, please see QIAGEN News article Issue No. 5, 1998 "Fast and efficient enzyme removal with QIAquick Spin kits."
DNA fragments purified with the QIAGEN DNA Cleanup Systems, i.e., the QIAquick PCR Purification Kit, the MinElute Reaction Cleanup Kit, the QIAEX II Gel Extraction Kit etc. may float out of the loading wells of agarose gels due to residual ethanol carried over from the wash step with Buffer PE (despite the addtition of glycerol-containing loading buffer).
Use either of the following options to remove residual ethanol from the eluate:
As a rule of thumb, single-stranded DNA binds to silica with approximately half the affinity of a double-stranded DNA fragment of the same length under the buffer conditions used in the QIAquick and MinElute Kits. Even though no systematic experimental data exists, we expect that recovery of ssDNA fragments of approximately 200 nucleotides and below will not be very efficient after cleanup using the QIAquick PCR Purification Kit or MinElute PCR Purification Kit. By comparison, it should be possible to purify fragments longer than 140 nucleotides using the QIAquick Gel Extraction Kit.
Note that recovery of single strand DNA is influenced to some degree also by factors such as base composition and secondary structure. It has to be determined empirically by the researcher if cleanup of single-stranded DNA with QIAquick columns yields satisfactory results.
The composition of Buffer EB is:
Buffer EB is the elution buffer used in the QIAquick PCR, Gel Extraction, Nucleotide Removal Kits, and MinElute Kits for DNA cleanup, and the QIAprep Miniprep Kits for small-scale plasmid purification. The purified DNA can also be eluted in TE (10 mM Tris-Cl, 1 mM EDTA, pH 8.0), but the EDTA may inhibit subsequent enzymatic reactions.
Occasionally, DNA fragments eluted from the silica matrix of QIAquick, MinElute or QIAEX II Kits will contain denatured single-stranded DNA (ssDNA), appearing as a smaller band on an analytical gel. Under certain conditions, chaotropic agents (present in all silica-based DNA purification methods) can denature DNA fragments. This is a rare event that may be influenced by sequence characteristics such as the presence of inverted repeats or A–T-rich stretches.
Because salt and buffering agents promote renaturation of DNA strands, the following tips are recommended:
We always provide extra buffers in our kits so you can scale up reactions, add extra washes or allow for spillage.