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Amplified DNA Product Separation for Forensic Analysts

Alternate Methods

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Reports of replacing formamide with water have been published.03, 04 The studies have shown that using water to denature the DNA produces results concordant with those processed with formamide.03 While water alleviates the risk of working with formamide, a known teratogen, there are drawbacks. For example, when samples are left in the autosampler tray of the instrument for several hours, the water rapidly evaporates and the DNA forms secondary structures. Formamide is effective in maintaining the DNA in a denatured state, whereas DNA stored in water will eventually renature.

Safety Note:

Formamide is a known teratogen and must be handled with care.


Reasons For Using Formamide Instead of Water

  • Formamide and water are good denaturing solvents; however, water can lead to the decomposition of DNA.
  • Formamide is more effective when working with larger DNA fragments and higher concentrations of DNA.
  • Formamide, an oily liquid with low volatility, is less likely to evaporate than water.
  • Formamide, unlike water, maintains the DNA in a denatured state, even under these circumstances:
    • In the presence of the alkaline stabilizer EDTA
    • When the sample remains at room temperature for extended time periods on the instrument

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