Dionex ASE 150, Руководство оператора

Страница: 34 / 176

ASE 150 Operator’s Manual
26
Doc. 065207-02 9/08
Guidelines for Selecting and Preparing Solvents
•
When developing a new method, select a solvent or solvent mixture
that has a high solubility for the analytes of interest, but not for the
sample matrix. If you have been using another method (Soxhlet, for
example), use the same solvent with the ASE 150 that you used with
the other method.
•
Before running a preprogrammed method, refer to Section 2.5 for the
recommended solvent.
•
Use HPLC-grade or pesticide-grade solvents.
•
Use organic or aqueous solvents.
•
Use single-component or multiple-component solvents.
•
Solvents do not generally need to be degassed. Degas solvents only if
the analyte of interest oxidizes easily.
•
If Viton external O-rings are installed on the cell end caps, do not use
acetone and other ketones.
•
Although the zirconium components in the ASE 150 flow path are
more resistant to acids and bases at elevated temperatures than other
metallic materials, follow these guidelines to prevent degradation and
ensure optimum performance:
a. As a general rule, strong mineral acids such as hydrochloric acid
should not be used (at any concentration) as extraction solvents.
This is because there are components in the flow path of the
system (for example, the pump head) that are constructed of
stainless steel and will corrode when used with strong acids.
Sulfuric acid or nitric acid can be pumped as a solvent at
concentrations less than 0.1% by volume. For additional details
about acids that can be pumped as solvents, see
Table 3-1 .
b. Weak bases such as ammonia can be used at small percentages
(<5% by volume). Strong bases such as sodium hydroxide or
potassium hydroxide can be pumped as extraction solvents at
concentrations less than 0.1% by volume. For additional details
about bases that can be pumped as solvents, see
Table 3-1 .
Using corrosive acids or bases can damage stainless steel cells and
will void the product warranty.