One of the most common methods for nucleic acid detection
is the measurement of solution absorbance at 260nm
(A260) due to the fact that nucleic acids have an absorption
maximum at this UV wavelength. Although a relatively simple
and time-honored method, A260 suffers from low sensitivity
and interference from nucleotides and single-stranded
nucleic acids. Furthermore, compounds commonly used in
the preparation of nucleic acids absorb at 260nm leading to
abnormally high quantitation levels.
However, these interference and preparation compounds also absorb at 280nm leading to the calculation of DNA purity by performing ratio absorbance measurements at A260/ A280.
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