Measure Oligo DNA or Oligo RNA
50 NanoDrop One User Guide Thermo Scientific
Calculated nucleic acid concentrations are based on the
absorbance value at 260 nm, the factor used and the
sample pathlength. A single-point baseline correction (or
analysis correction) may also be applied.
Concentration is reported in mass units. Calculators are
available on the Internet to convert concentration from
mass to molar units based on sample sequence.
Absorbance values at 260 nm, 280 nm and sometimes
230 nm are used to calculate purity ratios for the
measured nucleic acid samples. Purity ratios are
sensitive to the presence of contaminants in the sample,
such as residual solvents and reagents typically used
during sample purification.
Measured Values
A260 absorbance
Note: For micro-volume absorbance measurements and measurements
taken with nonstandard (other than 10 mm) cuvettes, the spectra are
normalized to a 10 mm pathlength equivalent.
• Nucleic acid absorbance values are measured at 260 nm using the
normalized spectrum. This is the reported A260 value if Baseline
Correction is not selected.
•If Baseline Correction is selected, the absorbance value at the
correction wavelength is subtracted from the sample absorbance at
260 nm. The corrected absorbance at 260 nm is reported and used to
calculate nucleic acid concentration.
A230, A280 absorbance
• Normalized absorbance values at 230 nm, 260 nm and 280 nm are
used to calculate A260/A230 and A260/A280 ratios.
Sample Pathlength
• For micro-volume measurements, the software selects the optimal
pathlength (between 1.0 mm and 0.03 mm) based on sample
absorbance at the analysis wavelength.
• For cuvette measurements, pathlength is determined by the cuvette
Pathlength setting in the software (see General Settings).
• Displayed spectra and absorbance values are normalized to a 10 mm
pathlength equivalent.
•
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