5. Operating the Instrument
2016-04
IFU for Infinite 200 PRO No. 30052730 Rev. No. 1.6
87
5.5
Optimizing Fluorescence Measurements
Fluorescence measurement results may be optimized by tuning instrument
parameters on the one hand, and by selecting appropriate materials on the other
hand.
5.5.1
Instrument Parameters
Gain Settings
The Infinite 200 PRO fluorescence detection system uses an analog to digital
(ADC: Analog Digital Converter) conversion of PMT signal. The gain setting
controls the amplification of the PMT when converting fluorescence light into
electrical current. The ADC needs a suitable input range of PMT current to
provide a proper signal to noise ratio (S/N) on the one hand, and linearity on the
other hand. Therefore, the gain should be tuned to make highest concentration
microplate wells give highest possible readings. Then, readings of lower
concentration microplate wells separate from background - as far as the
background noise level allows for that.
Note
If any well of interest is assigned “OVER” (overflow), you may manually
reduce the gain, or select an automatic gain option (see the software
Instructions for Use.
PMT Properties
The Infinite M200 PRO and F200 may be equipped optionally with a ‘standard’
and a ‘spectrally enhanced’ PMT.
The gain for fluorescence intensity is selectable from 1 – 255. The performance
of the PMT depends on the supply voltage. The Infinite 200 PRO PMTs are
specified from 300 to 1250 V. The relationship between the gain settings of the
Infinite 200 PRO and the voltage supply is described in Equation 1. The intended
use of the Infinite 200 PRO PMT is therefore specified for gain settings from 60 to
255. Gain settings below 60 are possible, but the performance of the PMT is not
specified for voltage supply < 300 V. Tecan therefore does not take responsibility
for measurement results of Infinite 200 PRO when using gain settings below 60.
