StarPure Plasmid Miniprep Kit (Membrane Column Method)

1. High plasmid extraction efficiency and good quality;
2. High purity, no RNA residue;

1. The extraction volume is higher than that of competing products on the market

The DH5α strain containing plasmids of different sizes, 5 kb, 3 kb, and 2 kb, was cultured in LB medium until OD ₆₀₀ ≈2.5, and were extracted using plasmid extraction kits from different manufacturers, with each sample being 1 mL of bacterial solution.
The final plasmid elution volume was 50 μL. The concentration and yield of plasmids extracted by Qihengxing were higher than those of other manufacturers.

2. The extracted product is of high purity and free of genomic and RNA contamination.

The DH5α strain containing plasmids of different sizes, 5 kb, 3 kb, and 2 kb, was cultured in LB medium until OD ₆₀₀ ≈2.5, and were extracted using plasmid extraction kits from different manufacturers, with each sample being 1 mL of bacterial solution.
The plasmid elution volume was 50 μL. The extracted product was subjected to electrophoresis and showed high purity with no genomic and RNA contamination.

Product ingredients:

Self-prepared reagents: Isopropanol, 75% ethanol.

Steps:

The following operation process is based on OD ₆₀₀ Take 1~2 mL of E. coli culture solution ≤4 as an example. If OD ₆₀₀ If the concentration is too high or the amount of bacterial solution increases, the reagent volume can be increased as appropriate, but the ratio of Resuspension Buffer, Lysis Buffer and Extraction Buffer must be kept unchanged to avoid affecting the extraction effect.

1. Take 1-2 mL of bacterial culture medium and place it in a centrifuge tube. Centrifuge it at 12000 rpm for 2 min or 4000 rpm for 10 min, and discard the supernatant completely.
2. Remove the centrifuge tube from the centrifuge, add 250 μL Resuspension Buffer (P1) and 5 μL RNase A, and vortex until the precipitate is completely suspended and the solution becomes white and turbid.
3. Add 250 μL Lysis Buffer (P2), invert the tube several times without vortexing, and let it stand for 1 min (the fragmentation state can be observed. If the bacterial concentration is too high, the lysis time can be extended to a maximum of 10 min).
4. Add 250 μL of Extension Buffer (P3), invert the tube several times, and let it stand for 5 minutes.
5. Centrifuge at 12,000 rpm for 10 min or 4,000 rpm for 20 min at 4°C. Transfer approximately 550 μL of the supernatant to a clean centrifuge tube for later use. Be careful to avoid any remaining foam in the supernatant (excessive foam can be removed by further centrifugation). A small amount of impurities remaining during transfer will be removed by washing in subsequent steps and will not affect product purity.
6. Add 250 μL of isopropanol to the centrifuge tube (containing the supernatant) in step 5, vortex and mix thoroughly, then transfer the liquid to the DNA adsorption column (the DNA adsorption column is placed in the collection tube) and incubate at room temperature for 10 minutes.
7. Centrifuge at 12,000 rpm for 1 min, discard the waste liquid in the collection tube, and put the adsorption column back into the collection tube.
8. Add 600 μL of 75% ethanol, centrifuge at 12,000 rpm for 1 min, and discard the waste liquid in the collection tube.
9. Repeat step 8 once.
10. Place the adsorption column back into the collection tube and centrifuge at 12,000 rpm for 1 minute. Note: This step is to remove any residual ethanol in the adsorption column, as residual ethanol may affect subsequent enzymatic reactions (enzyme digestion, PCR, etc.).
11. Place the adsorption column in a new collection tube. Add 50-100 μL of Elution Buffer to the center of the adsorption membrane. Incubate at room temperature for 2-5 minutes. Centrifuge at 12,000 rpm for 2 minutes to collect the plasmid solution in a centrifuge tube. Store the plasmid at -20°C.