5. Operating the INFINITE M1000 PRO
2011-09
Instructions for Use for INFINITE M1000 PRO No. 30064852 Rev. No. 1.0
65
5.4.2 Absorbance
Ratio
Mode
Ratio Mode
When using the “Standard” tab in i-control, up to 5 labels can be measured well-
wise. This measurement mode is called ‘ratio mode’. Be aware that no ‘ratio’
calculation is performed after this measurement. The Excel result sheet shows
the raw data; further calculations must be performed by the user.
When using the “Applications” tab in i-control together with the NanoQuant Plate,
the raw data for “Quantifying Nucleic Acids” and “Labeling Efficiency” are all
automatically calculated for concentration or ratio-calculation by Excel software.
The values can be used for further calculation if preferred.
5.4.3 Measurement
Accessories
Recommended Types of Microplates
Generally, for absorbance measurements, transparent or UV-transparent
microplates are used. For high OD values, black microplates with transparent
bottoms seem superior.
Note
For absorbance measurements of nucleic acids in small volumes (2 µl),
use Tecan’s NanoQuant Plate
TM
. With this device it is possible to
measure 16 different samples in one measurement.
For further information, please contact your local Tecan distributor or
5.5
Optimize Luminescence Measurements
5.5.1 Integration
Time
At very low light levels, a PMT does not yield a continuous output current, which
is necessary for a reliable analog to digital conversion, but instead a sequence of
pulses are produced, the average rate of which can be measured using a
counter. The advantage of using the photon counting technique at such low light
levels is that pulse height selection criteria allow much of the electronic noise to
be filtered out.
At very low light levels, the measured counts per second are proportional to the
light intensity. Increasing the measurement time per well yields more accurate
values because of the irregular photon impact (photon statistics). The photonic
noise (shot noise) cannot be reduced further by technical means.
Note
The relevant signal to (shot) noise ratio can be improved by a factor
when measurement time is multiplied with the square of the desired
factor.
Note
If a luminescence measurement results in an INVALID
in one or more wells because the measured signal was too high,
the Luminescence PMT may need a certain amount of time
to return to the equilibrium baseline count level.
