Nucleic Acid Concentration (A260)
DNA/RNA concentration from a 260 nm read, plus the 260/280 purity ratio.
Example
You enter
- A260 (absorbance at 260 nm) 0.6
- Nucleic-acid type dsDNA
- Dilution factor 50
- A280 (optional, for 260/280 purity) 0.324
You get
- Concentration 1500
- Purity 260 280 1.85
Checked against published worked examples from: Standard spectrophotometric nucleic-acid quantitation (A260).
Details, formula, and sources
ScopeDNA/RNA concentration from a 260 nm read using the mass extinction factor (50 dsDNA, 33 ssDNA/oligo, 40 RNA) and dilution, plus the 260/280 purity ratio that flags protein or phenol carryover. Off every NanoDrop or cuvette read.
Formula or tableconcentration = A260 x factor x dilution (factor 50 dsDNA, 33 ssDNA/oligo, 40 RNA, ug/mL per A260); purity_260_280 = A260 / A280.
Source and editionA260 nucleic-acid quantitation (Beer-Lambert at 260 nm; standard spectrophotometric mass factors), by name.
Free accessStandard molecular-biology spectrophotometry; the mass factors are established practice. The sample and instrument govern.
What governsEstimate. AHJ and licensed professional govern.
API field namesa260, na_type, dilution_factor, a280, concentration_ng_ul, purity_260_280
- Mass extinction factor 50 dsDNA / 33 ssDNA, oligo / 40 RNA ug/mL per A260; empirical, not molarstandard spectrophotometry