MinElute Reaction Cleanup Kit

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.

The MinElute spin columns included in the following kits should be stored at 2–8°C upon arrival: AllPrep DNA/RNA Micro, EpiTect Fast DNA Bisulfite, EpiTect Fast FFPE Bisulfite, EpiTect Fast LyseAll Bisulfite, EpiTect Plus DNA Bisulfite, EpiTect Plus FFPE Bisulfite, EpiTect Plus LyseAll Bisulfite, exoRNeasy Serum/plasma Maxi, exoRNeasy Serum/Plasma Midi, GeneRead DNA FFPE, GeneRead rRNA Depletion, GeneRead Size Selection, MinElute Gel Extraction, MinElute PCR Purification, MinElute Reaction Cleanup, miRNeasy FFPE, miRNeasy Micro, miRNeasy Serum/Plasma, QIAamp DNA FFPE, QIAamp DNA Investigator, QIAamp DNA Micro, QIAamp MinElute Media, QIAamp MinElute Virus Spin, QIAamp MinElute Virus Vacuum, RNeasy FFPE, RNeasy Micro, RNeasy Plus Micro.

Short-term storage (up to 4 weeks) at room temperature (15–25°C) does not affect the performance. However, for optimal performance and quality, storage temperature should not exceed 25°C.

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:

• re-purify the sample using a QIAquick-, or MinElute column, or QIAEX II resin
• incubate the eluate at 56°C for 10 min to evaporate the ethanol
• dry down the sample in a vacuum centrifuge, and resuspend the pellet in a small volume of sterile water

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.