Performing An Array Calibration - Thermo Scientific Surveyor PDA Plus Hardware Manual

Performing an Array Calibration

Thermo Scientific
The function of the array calibration is to measure and correct for the dark current produced
by the diodes of the photodiode array. The dark current is the small amount of background
signal that is produced by the diodes of the array even when both lamps are turned off. Typical
dark current values range from 1500 to 3000 counts.
Because the environmental conditions of your laboratory can cause the dark current of the
diode array to increase over time, Thermo Fisher Scientific recommends that you perform an
array calibration (dark current) after 100 hours of use or monthly, whichever comes first;
whenever a significant temperature change occurs; after you move the detector; after you
replace the lamps; and after you download a new firmware file.
Because the dark current produced by the diodes rises as the temperature within the detector
rises, it is important to warm up the lamps for 1 hour before you perform a dark current
calibration. Warming up the lamps for 1 hour allows the detector to equilibrate to its normal
operating temperature.
ChromQuest briefly turns the lamps off as it performs the dark current calibration routine.
After it completes the dark current calibration routine, ChromQuest turns the lamps back on.
Note The dark current calibration program does not run when data collection is enabled
on the Display page.
 To perform a dark current calibration of the diode array
1. Pump HPLC grade water or methanol at 1 mL/min through the flow cell for at least one
hour.
2. Place the filter wheel of the Surveyor PDA Plus Detector in position 1 (Open).
3. Turn on both lamps and wait one hour for the D
a. In the menu bar of the online Instrument window, choose Control > Instrument
Status to open the Instrument Status window.
b. Click the Surveyor PDA Plus tab to open the Surveyor PDA Plus page (see
Figure 57).
c. Under D2 Lamp, click On. Under W Lamp, click On.
Equilibrating the lamps for one hour allows the detector to reach its normal operating
temperature.
4. Click Diagnostics.
The PDA Plus Diagnostics dialog box appears.
5. Click the Calibration tab to display the Calibration page (see
5
ChromQuest Diagnostics for the PDA Detector
Calibrating the Detector with ChromQuest
lamp to equilibrate:
2
Figure 60
Surveyor PDA Plus Detector Hardware Manual
on page 66).
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