June 11, 2015, 715004754 Rev. A
Page 112
7.3.4 Incorrect qualitative or quantitative results
If a peak is incorrectly identified by a data system or integrator, ensure that the
retention times are correct.
If retention times are correct and peak resolution is good, the cause of qualitative and
quantitative errors is not likely to be chromatographic. It is more likely to the result of
inadequate sample preparation or incorrect data processing (integration).
Table 7–5: Resolution troubleshooting
Symptom Possible cause Corrective action
Straight baseline, no
peaks
No pump flow Set pump flow rate.
LED not on Call Waters Technical
Service.
Detector not zeroed
Improper connection
between detector and
recorder
Autozero detector baseline.
Inspect cabling between
unit and recorder.
Solvent and sample have
similar refractive indices
Select a different solvent.
Sensitivity too low Select higher sensitivity.
No sample injected Inspect injector.
Leak in solvent path Inspect fittings and drip
tray.
Bad flow cell Inspect and clean or flush
flow cell.
Call Waters Technical
Service.
Bad column Inspect and clean, flush, or
replace column.
Call Waters Technical
Service.
Flat-topped peaks Detector not zeroed Autozero detector baseline.
Incorrect recorder input
voltage
Adjust recorder input
voltage, or adjust detector
output cable to correct
position.
Sensitivity too high Select a lower sensitivity.
Sample concentration or
injection volume exceeds
voltage output of detector
Decrease sample
concentration or injection
volume.
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