NanoPhotometer
®
N120/
NP80/N60/N50/C40
User Manual Version 4.3.1
66
nucleic acid samples can be calculated with or without background correction depending on
enabled/disabled background correction parameter.
Without background correction:
C = A
260
* ε
nuc
* Đ
With background correction:
C =
(
A
260
- A
BKG
)
* ε
nuc
* Đ
C
Concentration in ng/µl
A
260
Absorbance at 260 nm (10 mm path)
A
BKG
Absorbance at selected background wavelength (10 mm path)
Đ
Manual dilution factor
ε
nuc
Extinction coefficient/nucleic acid factor in ng*cm/µl
Table 1. Nucleic acids extinction coefficients (
ε
nuc
)
Type
ε
nuc
dsDNA
50 ng*cm/µl
ssDNA
37 ng*cm/µl
RNA
40 ng*cm/µl
miRNA
33 ng*cm/µl
Oligo
33 ng*cm/µl
miRNA Seq. calculated via extinction coefficient of constituent nucleotides entered
Oligo Seq.
calculated via extinction coefficient of constituent nucleotides entered
Custom
Option to enter any factor between 15 and 150 ng*cm/µl
Dye-labeled Nucleic Acid Concentration
For dye-labeled nucleic acids, the concentration of the nucleic acid is calculated using a
modified form of the Beer-Lambert equation. For these calculations, the instrument
considers the absorption maximum of the dye and a certain dye-specific correction factor at
260 nm (see Table 2 on page 68). The concentration of a dye-labeled nucleic acid is
calculated with or without background/dye correction as follows:
With background and with dye correction:
C =
[(
A
260
−
A
BKG
) −
(
cf
dye
*
(
A
max,
dye
−
A
BKG
))]
* ε
nuc
* Đ
With background and without dye correction:
C =
(
A
260
−
A
BKG
)
* ε
nuc
* Đ
Without background and with dye correction:
C =
[
A
260
−
cf
dye
* A
max,
dye
]
* ε
nuc
* Đ
Without background and without dye correction:
C = A
260
* ε
nuc
* Đ