11
Table 2.10 lists potential causes, confirmation methods, and methods for dealing
with shortening retention times.
Table 2.10 Dealing with Shortening Retention Times
Cause
Confirmation Method
What to Do
Column deterioration
Replace the column
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
2.3.3 Poor reproducibility for retention time
Table 2.11 lists potential causes, confirmation methods, and methods for dealing
with poor reproducibility in retention times.
Table 2.11 Dealing with Poor Reproducibility for Retention Time
Cause
Confirmation Method
What to Do
Variations in pump flow rate Check pressure variation
See Section 2.1.3
Use of improper eluent
Examine the eluent
conditions
Variations in ambient
temperature
Is a breeze from the air
conditioner striking the
column?
Protect the column
using thermal
insulation
2.3.4 Poor reproducibility for peak areas or peak heights
(reproducibility for retention times is good)
When retention time reproducibility is normal, the pump is most likely not the cause,
and the source of the problem is likely to be found in the sample injection section
(manual injector or autosampler) or may be due to deterioration of the sample itself.
2.3.5 Peak waveform problems (peak broadening, peak splitting)
Peak waveform problems indicate the use of an improper eluent solvent, a
deteriorated column, a failed fitting, or excessive injection of sample.
2.4 Pump section leaks
This section describes how to isolate and deal with solvent leaks occurring in the
pump section. Refer to Chapter 5 for instructions on how to replace parts.
Figure 2.2 indicates locations at which leakage can potentially occur. When a leak
has been found, refer to Sections 2.4.1 ~ 2.4.6 for information regarding methods for
dealing with solvent leaks that occur in the pump section.