Pure DNA refers to DNA that is free from contaminants, such as proteins, RNA, and other molecules. The purity of DNA is typically assessed using a spectrophotometer, which measures the absorbance of light at different wavelengths. The ratio of absorbance at 260 nm to 280 nm (A260/A280) is a common indicator of DNA purity. A ratio of approximately 1.8 is generally considered "pure" for DNA.
Here are some additional points to consider:
- Contaminants: Contaminants can affect downstream applications, such as PCR, sequencing, and cloning.
- Other Purity Indicators: The absorbance at 230 nm can also be used to assess DNA purity, as it indicates the presence of contaminants such as salts, phenol, and other organic compounds.
- Methods for DNA Purification: Various methods are used to purify DNA, including phenol-chloroform extraction, silica-based purification, and column chromatography.
