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GENESYS 30 User Guide
Thermo Scientific
OD600
Measurement wavelength:
Default is 600 nm, but some users make cell count measurements
at different wavelengths and may wish to change it.
Factors in OD600:
When measuring the “absorbance” of a suspension of cells, you are really
measuring the attenuation of the beam due to scattering. It is not the same as colorimetry.
The impact of scattering on the measured amount of transmitted light depends on a number
of factors, including the overall optical design of the spectrophotometer. Differences in the
designs of different spectrophotometers mean that the measured “absorbance” of a cell
suspension is not expected to be the same on all instruments. The difference can be accounted
for by multiplying data by a uniform factor. If you want to display the results obtained on
your GENESYS 30 on the same scale reported by another instrument, simply measure the
same sample on both instruments and calculate the number by which you would need to
multiply the GENESYS 30 result to yield the value on the other instrument. It is best to do
this over a range of cell concentrations and use an average number as your factor because you
may see some variation from data point to data point.
Enter the result of your calculation as the factor when you run the OD600 application on the
GENESYS 30 and the result shown in the Value field will be scaled to your old or other
instrument. The “raw” absorbance value is also shown on the screen.
Measurement wavelength
Enter factor if desired
Baseline status
indicator
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instructions and reports
