Thermo Scientific NanoDrop One User Manual page 95

Calculated protein concentrations are
based on the absorbance value at 280 nm,
the selected (or entered) extinction
coefficient and the sample pathlength. A
single-point baseline correction (or analysis
correction) may 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.
Dye concentrations are calculated from the
absorbance value at the dye's analysis
wavelength, the dye's extinction coefficient,
and the sample pathlength. A sloped-line
dye correction may also be used.
Thermo Scientific
Measured Values
A280 absorbance
Note: The absorbance value at 750 nm is subtracted from all
wavelengths in the spectrum. As a result, the absorbance at
750 nm is zero in the displayed spectra. Also, 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.
• Protein absorbance values are measured at 280 nm
using the 750 nm-corrected and normalized spectrum. If
Analysis Correction and Dye Correction are not selected,
this is the reported A280 value and the value used to
calculate protein concentration.
• If Analysis Correction
normalized and analysis-corrected absorbance value at
280 nm is reported and used to calculate protein
concentration.
• If a Dye is used, the 750-corrected, normalized,
analysis-corrected and
at 280 nm is reported and used to calculate protein
concentration.
Dye absorbance
• Dye absorbance values are measured at specific
wavelengths. See
wavelengths used.
• If Sloping Dye Correction is selected, a linear baseline is
drawn between 400 nm and 750 nm and, for each dye,
the absorbance value of the sloping baseline is
subtracted from the absorbance value at each dye's
analysis wavelength. Baseline-corrected dye absorbance
values are reported and used to calculate dye
concentrations.
Dye correction
• Pre-defined dyes have known correction values for A260
and A280. See Dye/Chromophore Editor
values used.
• A280 dye correction is subtracted from
value used to calculate protein concentration.
5
Protein Applications
Measure Proteins and Labels
is selected, the 750-corrected,
dye-corrected absorbance value
Dye/Chromophore Editor
A280 absorbance
NanoDrop One User Guide
for analysis
for correction
93