Selection Of Mobile Phase And Cautions On Handling - Hitachi CHROMASTER 5160 Instruction Manual

3.6.1 Selection of Mobile Phase and Cautions on Handling

(1) Be careful about restriction on use due to characteristics
and temperature of mobile phase to be used. (See Table
3-10 Characteristics of Organic Solvents)
(2) When performing high sensitivity analysis with a UV
detector, use solvents whose UV absorption characteristics
are especially small. Use solvents for liquid
chromatograph commercially available.
Absorption characteristics of special grade reagents such
as methanol, ethanol and acetonitrile generally and widely
used are greatly different in the short wavelength range,
depending on the manufacturing lot and the manufacturer.
Be careful especially when performing high sensitivity
analysis.
(3) Degas the mobile phase before use without fail.
(a) It is recommended to use a degassing unit because
organic solvents have a specially high content of air,
and the baselines may be fluctuated by bubbles.
Malfunction of check valve and loss of column
efficiency may also be caused. Degassing unit is
especially required for mixing solvents for gradient use.
Degas the solvents before use seeing 3.7.2 Degassing
Mobile Phase.
(b) When performing analysis with a UV detector in the
short wavelength range or highly sensitive analysis
with an RI detector, degassing the mobile phase
before use is not enough, and the baselines may be
fluctuated by the bubbles. In such a case, use
degassing unit which can degas mobile phase on-line.
(4) Mobile Phase
When using mobile phase for liquid chromatograph, since
the connections of pipings of pump and separation column
use stainless steel (SUS316), solvents or reagents that
may corrode stainless steel may be restricted.
Especially, solvents or solutions which contain halogen
ions such as HCl, KCl, NaCl, NH
Reagents which may be restricted are shown in Table 3-9
use the table as a rough standard.
3 - 66
Cl are typical reagents.
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