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Dionex PDA Operator's Manual
Without the column, backpressure is usually less than 0.34 MPa (50 psi),
depending on the flow rate and tubing ID. Note that the semi-micro flow
cell will develop approximately 1.03 MPa (150 psi) backpressure at
1.0 mL/min.
If the backpressure remains high, remove the fittings and tubing from part
of the flow path, section by section; starting at the waste line, work back
"upstream" until you identify the section causing the substantial
backpressure. Replace tubing and fittings as necessary.
•
Periodically check the flow cell tubing connections for leaks or restrictions.
Replace tubing and fittings as necessary.
•
Periodically repassivate stainless steel systems. This is especially important
when operating with extreme pH levels (which will shorten the life of the
passivation finish) or after a major disassembly. For instructions, see
Passivation of Stainless Steel Systems and Components (Document No.
031152).
•
Monitor baseline noise. If the noise increases above an acceptable level,
especially after a lamp(s) has been in service for an extended length of time,
replace the lamp.
To check the lamp lifetime:
1. Open the Chromeleon 7 Command window (see
Chromeleon 6.8 Commands dialog box (see
2. Select UV, and then select UVLampAge and VisLampAge. If a lamp has
been in service for more than 2000 hours, replace it. See
Section 5.8
lamp, respectively.
•
Check the deuterium lamp intensity approximately every 6 months:
1. Open the Chromeleon 7 Command window (see
Chromeleon 6.8 Commands dialog box (see
2. Select UV, and then select LampIntensity. The reading should be above
10 million counts for a standard or semi-preparative cell or above 3
million counts for a semi-micro cell.
3. If the lamp intensity reading is too low, calibrate the intensity: In the
Command window or Commands dialog box, select UV_Calibration,
select Intensity, and execute the command.
56
for instructions on replacing the deuterium lamp or tungsten
page
31) or the
page
32).
Section 5.7
page
31) or the
page
32).
Doc. 065378-01 1/12
or
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