UV absorbance DNA quantitation

Franka Ganske BMG LABTECH 12/2014

One of the most common methods for nucleic acid detection is the measurement of solution absorbance at 260 nm (A260) due to the fact that nucleic acids have an absorption maximum at this UV wavelength. Furthermore, compounds commonly used in the preparation of nucleic acids absorb at 260 nm leading to abnormally high quantitation levels. However, interfering compounds absorb at 280 nm or 230 nm. DNA purity is estimated by ratio calculations of 260/280 or 260/230.


Because of its spectrometer, BMG LABTECH microplate readers offer easy handling for DNA absorbance measurements by measuring a spectrum which covers the absorbance maximum. The MARS Data Analysis Software calculates nucleic acid concentrations depending on the extinction coefficient. The ratio of A260/A280 indicates purity of the DNA and it can be measured in parallel with A260. A full absorbance spectrum in the range of 220-1000 nm helps to identify impurities and it can be measured within one second per well.

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