Hitachi CHROMASTER 5160 Instruction Manual page 332

3.6 Before Analysis
(3) Be sure to degas the mobile phase before its use.
(a) Because an organic solvent has a particularly high air
content, fluctuations of the baseline, malfunction of the
check valve and a fall in column efficiency may be
caused by air bubbles. Therefore, use of a degassing
unit is recommended. It is indispensable when mixing
solvents for gradient elution. Organic solvents should
be used after degassing, referring to "Degassing of
Mobile Phase" in 3.7.2.
(b) For analysis in the shorter wavelength region with the
UV detector or high sensitivity analysis with an RI
detector, degassing before using the mobile phase
may not suffice, so the baseline may fluctuate due to
bubbles, etc. In this case, use a degassing unit
capable of degassing the mobile phase online.
(4) On Mobile Phase
The wetted parts of the liquid delivery line consisting of
pump, separation column, etc. are made of stainless steel
(SUS 316). Therefore, use of the solvents and reagents
which can corrode this material may be somewhat
restricted. The typical example of such reagents are
solvents and solutions containing halogen ions of HCl, KCl,
NaCl, NH Cl, etc. The reagents whose use may be
4
restricted are listed in Table 3-1. Utilize it as a referential
table.
NOTE: If an undesirable but indispensable reagent was
used unavoidably for constituent separation,
reaction, etc. or the mobile phase which will cause
precipitation of salt was used, be sure to wash the
entire flow path adequately with distilled water
after analysis. If this washing is neglected, the
plunger will be worn. Before using the mobile
phase which may cause precipitation of salt, be
sure to fill the plunger washing mechanism with
pure water in order to prevent salt precipitation on
the plunger and plunger seal. And, after
analysis, inject water into the plunger washing
mechanism at the rear of pump head for washing.
For details of washing method, refer to "3.1.6
Washing after Use."
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