Invitrogen Qubit 2.0 - Page 35

35
Critical Qubit
™
Assay Considerations, Continued
Photobleaching
of Qubit
™
Reagents
The Qubit
™
reagents exhibit high photostability in the Qubit
®
2.0
Fluorometer, showing <0.3% drop in fluorescence after 9 readings
and <2.5% drop in fluorescence after 40 readings. It is important
to remember, however, that if the assay tube remains in the
Qubit
®
2.0 Fluorometer for multiple readings, a temporary
reduction in fluorescence will be observed as the solution
increases in temperature (see Figure 2 in Assay Temperature,
previous page). Note that the temperature inside the Qubit
®
2.0
Fluorometer may be as much as 3°C above room temperature
after 1 hour. For this reason, if you want to perform multiple
readings of a single tube, remove the tube from the instrument
and let it equilibrate to room temperature for 30 seconds before
taking another reading.
Calibrating the
Qubit
®
2.0
Fluorometer
For each assay, you have the choice to run a new calibration or to
use the values from the previous calibration. As you first use the
instrument, you should perform a new calibration each time. As
you become familiar with the assays, the instrument, your
pipetting accuracy, and significant temperature fluctuations
within your laboratory, you should determine the level of
comfort you have using the calibration data stored from the last
time the instrument was calibrated. Remember also that the
fluorescence signal in the tubes containing the standards and the
samples is stable for not longer than 3 hours. See Figure 1 in How
the Qubit
®
2.0 Fluorometer Calculates Concentration (page 33)
for an example of the calibration curve used to generate the
quantitation results.