Thermo NanoDrop One, User Manual, Page: 27 / 312

Measure dsDNA, ssDNA or RNA
Thermo Scientific NanoDrop One User Guide 21
Reported Values
• Nucleic acid concentration . Reported in selected unit (i.e., ng/μL,
μg/uL or μg/mL). Calculations are based on modified Beer’s Law
equation using corrected nucleic acid absorbance value.
• A260/A280 purity ratio . Ratio of corrected absorbance at 260 nm to
corrected absorbance at 280 nm. An A260/A280 purity ratio of ~1.8 is
generally accepted as “pure” for DNA (~2.0 for RNA). Acidic solutions
may under represent the reported value by 0.2-0.3; the opposite is true
for basic solutions.
• A260/A230 purity ratio . Ratio of corrected absorbance at 260 nm to
corrected absorbance at 230 nm. An A260/A230 purity ratio between
1.8 and 2.2 is generally accepted as “pure” for DNA and RNA.
Note : Although purity ratios are important indicators of sample quality,
the best quality indicator quality is functionality in the downstream
application of interest (e.g., real-time PCR).