10
Table 2.7 Dealing with Periodic Baseline Drift
Cause
Confirmation Method
What to Do
Variations in ambient
temperature
Is a breeze from the air
conditioner striking a
column or detector?
Protect the column
using thermal
insulation or a
windbreak
2.2.5 Appearance of ghost peaks
Table 2.8 lists potential causes, confirmation methods, and methods for dealing with
ghost peaks.
Table 2.8 Dealing with Ghost Peaks
Cause Confirmation
Method
What to Do
Contamination of pump or
equipment upstream from the
pump
Clean using an acid or
an alkaline solution
(See Section 4.3)
Eluent contamination
Use a higher grade
eluent
Contamination in sample
injection section (manual
injector or autosampler)
Watch the ghost
peaks while injecting
eluent in the sample
injection section
Clean any equipment
that has been
determined to be
contaminated
2.3 Chromatogram
problems
2.3.1 Lengthening retention time
Table 2.9 lists potential causes, confirmation methods, and methods for dealing with
lengthening retention times.
Table 2.9 Dealing with Lengthening Retention Times
Cause
Confirmation Method
What to Do
Decrease in actual flow
rate
See Section 2.1.2
Insufficient column
equilibration
Increase the column re-
equilibration time
Variation in ambient
temperature
Is a breeze from the air
conditioner striking the
column?
Protect the column
using thermal insulation
Variation in eluent
composition
Prepare the eluent
again
2.3.2 Shortening retention time
