Sample Files

DsDNA Quantification Blank Plate

November 20, 2012


Related Products: Gen5 for Detection

Gen5 version required: 1.0 or higher

Basis for the Assay:

The aromatic ring structure of the purine and pyrimidine moieties that make up the nucleoside bases of DNA and RNA are responsible for absorbance of UV light at 260 nm. Although each specific base has a maximal absorbance at a slightly different wavelength, on average, nucleic acids as a macromolecule will absorb maximally very near 260 nm. In terms of quantitation, different nucleic acid species have different average extinction coefficients. By converting these known extinction coefficients to a specific concentration for a particular absorbance value at a defined wavelength, the nucleic acid concentration of solutions can be determined by a simple absorbance measurement. For example, the extinction coefficient for dsDNA (1 mg/ml) at 260 nm is 20 ODs for a 1 cm pathlength; this can be recalculated to mean 1.0 OD has a concentration of 50 μg/ml.

The protocol calls for a pre-read of the microplate to subtract the background absorbance of the microplate at 260 nm, followed by an absorbance measurement at 260 nm. Pathlength correction is selected to correct the absorbance value to reflect a pathlength of 1 cm. The corrected absorbance is then used in a single plate transformation to calculate DNA concentration. The experiment file contains all of the absorbance determinations necessary including the pre-read plate (260 blank), the absorbance determinations at 977 nm (Test) and 900 nm (Reference), which are utilized to correct for pathlength, as well as the 260 nm experimental determination.

Plate Configuration:

Plate configuration includes samples in duplicate. There are no blanks or controls.


The report contains a matrix with: 1. Raw absorbance values 2. Absorbance corrected to 1 cm pathlength 3. Calculated DNA concentration. The report also contains a table with the corrected ODs, calculated concentrations and standard deviation and % CV of the replicate sets.