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SECTION 6 – STEP BY STEP GUIDE TO MAKING A DNA MEASUREMENT
The DNA measurement mode of the Genova Nano allows the user to select a method from a list of
common nucleic acid measurement tests, including single wavelength concentration
measurements for dsDNA, ssDNA, RNA and Oligonucleotides and methods that use absorbance
ratios for estimating nucleic acid purity, such as 260nm/280nm and 260nm/230nm. Section 14 of
the Genova Plus manual gives further details of the DNA measurement modes.
6.1
dsDNA Mode
This mode simply multiplies the A260 reading by a factor of 50 for dsDNA to calculate the
concentration in µg/ml. An additional factor for the path length is also included automatically by the
instrument.
1. From the
Life Science
screen select the
DNA mode:
, followed by
dsDNA
.
2. Press the button next to the
Settings Menu
icon:
and check that the wavelength is set to
260nm, the units are µg/ml and F1 = 50.
3. Lift the lid of the Genova Nano and pipette 2µl of water onto the read head. Close the lid.
Perform the
Blank Reading
:
4. Lift the lid and wipe the water from both the upper and lower read heads.
5. Pipette 2µl of the DNA sample onto the read head. Close the lid and perform the
Sample
Reading
:
. Record the results.
6.2 A260/280 Mode
This method uses the equation:
Concentration (
µ
g/ml) = (Abs@260nm x 62.9) - (Abs@280nm x 36.0).
This equation takes into account any contamination present which may absorb at 280nm (e.g.
protein).
1. From the
Life Science
screen select the
DNA mode:
, followed by
260/280
.
2. Press the button next to the
Settings Menu
icon:
. Check that the settings are as follows:
Wavelength 1: 260; Wavelength 2: 280; Wavelength 3: 230; units, µg/ml.
3. Touch the button next to the
Calculation Factors
icon:
and check that Factor 1 = 62.9;
Factor 2 = 36.0; Sum,=(xF1*A1)-(xF2*A2).
4. Press the button next to the
Tick
icon twice to return to the measurement screen.
