PL-GPC 220 User Manual 95
Maintenance
7
Differential Refractive Index Detector
Flush the DRI Cell with a Cleaning Agent
Flush the sample side of the cell
1 Connect the inlet tubing of the DRI directly to the injection valve outlet
using the wide bore Parker barrel connector provided.
2 Switch on the pump and set the flow rate at 1.0 mL/min.
Flush the reference side of the cell
1 Remove the purge column and replace it with a wide bore barrel connector.
2 Blank off the outlet of the injection valve and open the purge valve.
3 Switch on the pump and set the flow rate at 1.0 mL/min.
Alternatively both sides of the cell could be continually flushed by changing
the plumbing from the conventional arrangement (Figure 17 on page 96) to
sample and reference in series (Figure 18 on page 96).
When • Purging the reference side of the DRI cell does not cure the baseline noise or lack of sensitivity.
• Back pressure across the DRI is determined to be higher than normal
If no flow is achieved through the DRI system, this exercise would prove ineffective and the problem
should be reported to Agilent.
The backpressure across the DRI system in THF at ambient temperature and at 1.0 mL/min
is typically ≤3bar.
The wettable parts in the DRI system are stainless steel, Hastalloy and quartz and thus the
most effective cleaning is achieved by pumping a dilute solution of nitric acid (20 %)
through the system.
Damage to the tubing
Some instruments contain nickel tubing in the DRI flow path.
➔ Do not flush instrument tubings containing nickel with nitric acid.
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