4
Nucleic Acid Applications
Measure dsDNA, ssDNA or RNA
Thermo Scientific
NanoDrop Eight User Guide 21
Calculations for Nucleic Acid Measurements
The Nucleic Acid applications use a
modification of the Beer-Lambert equation
(shown at right) to calculate sample
concentration where the extinction
coefficient and pathlength are combined
and referred to as a “factor.”
Extinction Coefficients vs Factors
Using the terms in the Beer-Lambert equation, factor (f) is
defined as:
factor (f) = 1/(
* b)
where:
= wavelength-dependent molar extinction coefficient in
ng-cm/µL
b =
sample pathlength
in cm
As a result, analyte concentration (c) is calculated as:
c = A * [1/(
* b)]
or
c = A * f
where:
c = analyte concentration in ng/µL
A = absorbance in absorbance units (A)
f
= factor in ng-cm/µL (see below)
For the dsDNA, ssDNA and RNA
applications, the generally accepted factors
for nucleic acids are used in conjunction
with Beer’s Law to calculate sample
concentration. For the Custom Factor
application, the user-specified factor is
used.
Factors Used
•
dsDNA
(factor = 50 ng-cm/µL)
•
ssDNA
(factor = 33 ng-cm/µL)
•
RNA
(factor = 40 ng-cm/µL)
•
Custom Factor
(user entered factor between
15 ng-cm/µL and 150 ng-cm/µL
Summary of Contents for NanoDrop Eight
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