ThermoFisher Scientific NanoDrop Eight, User Manual

Page: 38 / 152

4 Nucleic Acid Applications
Measure Oligo DNA or Oligo RNA
38 NanoDrop Eight 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
0.1 mm) based on sample absorbance at the
analysis wavelength.
• Displayed spectra and absorbance values are
normalized to a 10 mm pathlength equivalent.