Dionex ICS-90 - Peak Ghosting

4 • Troubleshooting
Doc. 031851-05 12/04 4-7
• Plugged or damaged fitting
Isolate the faulty fitting by loosening fittings, one by one, until the pressure
returns to normal. Repair or replace the fitting (see Section 5.2
).
• Flow rate through the columns too high
Measure the pump flow rate and set it to the correct rate (see Section B.14
).
• Clogged column bed supports
Refer to the instructions in the column manual for troubleshooting guidance.
The column manual is included on the Dionex Reference Library CD-ROM
(P/N 055405), located in the ICS-90 Ship Kit.
• Contaminated columns
Clean the columns as instructed in the column manual.
• Plugged Rheodyne valve passages
Rebuild the injection valve (see Section 5.9
).
4.8 Peak “Ghosting”
Ghosting is the appearance of extraneous peaks in a chromatogram. These may be
late-eluting peaks from a previous injection or they may result from a
contaminated, malfunctioning, or incorrectly installed injection valve. These
peaks may co-elute with peaks of interest, resulting in nonreproducible peak
heights/areas.
• Insufficient time between sample injections
Wait until the previous sample has been completely eluted before making
another injection.
• Insufficient flush between samples
Flush the sample loop with at least 10 loop volumes of deionized water or
sample between sample injections.
• Incorrect or contaminated standards
Remake standards.
• Incorrect or contaminated eluent
Remake the eluent (see Section 3.1
).