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DNA Extraction and Quantitation for Forensic Analysts

Absorption Spectrophotometry

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Image of Absorption Spectrophotometry graph showing Absorbence on y axis and Wavelength on x axis
National Institute of Justice (NIJ) (see reuse policy).

Absorption spectrophotometry is a widely used technique in analytical chemistry based on the property of molecules to absorb light at specific wavelengths. The optical density (O.D.) of a solution containing 50 µg/mL of double-stranded DNA or 40 µg/µl of single-stranded DNA is 1.00 at a wavelength of 260nm.04The quality or purity of the sample can be determined by comparing the measurements at 260 and at 280 nm (the wavelengths for which DNA and protein absorb).

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