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INPUT   DATA

♥ EXAMPLE Of Input/Output

Title

Sample Absorbance, A260
Dilution factor (undiluted = 1.)

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OUTPUT   VARIABLES   &   GRAPHS

Stock	Values	Units
♦  Concentration, if DNA		μg/ml
♦  Concentration, if ssDNA		μg/ml
♦  Concentration, if RNA		μg/ml
♦  Concentration, if ss Oligo		μg/ml

Quantification Of Nucleic Acids

With the aid of spectroscopy, the quantitative analysis of nucleic acids and proteins is now an established method in many laboratories. Nucleic acids absorb Ultraviolet light of 250 to 270nm wavelength, with a maximum at 260nm. The reading at 260nm allows calculation of the concentration of nucleic acid in the sample and in the original stock.

The absorbance A₂₆₀ (also referred to as: optical density, OD) of 1 corresponds to approximately 50μg/ml for double-stranded DNA [DeoxyriboNucleic Acid], 33μg/ml for single-stranded DNA, 40 for RNA [RiboNucleic Acid], and 20 - 30 for Oligonucleotides. Thus the conversion factor for dsDNA can be considered to be 50, 40 for RNA and 25 for the oligos.

The applicable equation is:

Stock Concentration = [A₂₆₀ reading] x [Dilution factor] x [Conversion factor for Nucleic acid type]

Tips

    ◊ Use link EXAMPLE Of Input/Output  to demo data entry expectations and results; you may edit & use it as starting point

BIBLIOGRAPHY

• Stephenson FH; Calculations For Molecular Biology And Biotechnology: A guide to mathematics in the laboratory; Academic Press, An Imprint of Elsevier, Amsterdam, 2003
• QIAGEN Inc., Valencia, CA, USA; Techical Information: Spectrophotometric Quantitation of Nucleic Acids, 2006