Lab Protocols

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Purification & buffer exchange

Phenol/chloroform extraction

Complete removal of protein, doesn't change buffer. Typically followed by ethanol precipitation. Has to be handle carefully in order not to get phenol contamination, which will inhibit any enzymatic reaction.

Ethanol Precipitation

The most robust purification method. Works for samples of any volume. Good for single-standed and double-stranded DNA across a wide range of size. Can not be used to remove short oligos. Purification takes longer (~1 hour) than column-based method. Difficult to quantify the precipitated DNA with spectrophotometer if co-precipitants (Glycogen, linear acrylamide) are used.

Column purification

Qiagen's Qiaquick column

Complete removal of protein and buffer. Good for both single stranded and double stranded DNA. Elution volume is slightly larger than MinElute column. Good for general purpose purification. More expensive than Bioneer's AccuPrep column.

Qiagen's MinElute column

Complete removal of protein and buffer. Small elution volume (10ul), great to obtain highly concentrated DNA. Yield is slightly lower than Qiaquick.

Bioneer's AccuPrep column

Complete removal of protein and buffer. Low cost, good for double stranded DNA. Questionable for single-stranded DNA.

Size exclusion purification

  • Sephadex G25, G50

Size selection column

  • Millipore: YM-10, YM-30, YM-50, YM-100